The feature-weighted receptive field: an interpretable encoding model for complex feature spaces.

PubMed

St-Yves, Ghislain; Naselaris, Thomas

2017-06-20

We introduce the feature-weighted receptive field (fwRF), an encoding model designed to balance expressiveness, interpretability and scalability. The fwRF is organized around the notion of a feature map-a transformation of visual stimuli into visual features that preserves the topology of visual space (but not necessarily the native resolution of the stimulus). The key assumption of the fwRF model is that activity in each voxel encodes variation in a spatially localized region across multiple feature maps. This region is fixed for all feature maps; however, the contribution of each feature map to voxel activity is weighted. Thus, the model has two separable sets of parameters: "where" parameters that characterize the location and extent of pooling over visual features, and "what" parameters that characterize tuning to visual features. The "where" parameters are analogous to classical receptive fields, while "what" parameters are analogous to classical tuning functions. By treating these as separable parameters, the fwRF model complexity is independent of the resolution of the underlying feature maps. This makes it possible to estimate models with thousands of high-resolution feature maps from relatively small amounts of data. Once a fwRF model has been estimated from data, spatial pooling and feature tuning can be read-off directly with no (or very little) additional post-processing or in-silico experimentation. We describe an optimization algorithm for estimating fwRF models from data acquired during standard visual neuroimaging experiments. We then demonstrate the model's application to two distinct sets of features: Gabor wavelets and features supplied by a deep convolutional neural network. We show that when Gabor feature maps are used, the fwRF model recovers receptive fields and spatial frequency tuning functions consistent with known organizational principles of the visual cortex. We also show that a fwRF model can be used to regress entire deep convolutional networks against brain activity. The ability to use whole networks in a single encoding model yields state-of-the-art prediction accuracy. Our results suggest a wide variety of uses for the feature-weighted receptive field model, from retinotopic mapping with natural scenes, to regressing the activities of whole deep neural networks onto measured brain activity. Copyright © 2017. Published by Elsevier Inc.

The Anatomical and Functional Organization of the Human Visual Pulvinar

PubMed Central

Pinsk, Mark A.; Kastner, Sabine

2015-01-01

The pulvinar is the largest nucleus in the primate thalamus and contains extensive, reciprocal connections with visual cortex. Although the anatomical and functional organization of the pulvinar has been extensively studied in old and new world monkeys, little is known about the organization of the human pulvinar. Using high-resolution functional magnetic resonance imaging at 3 T, we identified two visual field maps within the ventral pulvinar, referred to as vPul1 and vPul2. Both maps contain an inversion of contralateral visual space with the upper visual field represented ventrally and the lower visual field represented dorsally. vPul1 and vPul2 border each other at the vertical meridian and share a representation of foveal space with iso-eccentricity lines extending across areal borders. Additional, coarse representations of contralateral visual space were identified within ventral medial and dorsal lateral portions of the pulvinar. Connectivity analyses on functional and diffusion imaging data revealed a strong distinction in thalamocortical connectivity between the dorsal and ventral pulvinar. The two maps in the ventral pulvinar were most strongly connected with early and extrastriate visual areas. Given the shared eccentricity representation and similarity in cortical connectivity, we propose that these two maps form a distinct visual field map cluster and perform related functions. The dorsal pulvinar was most strongly connected with parietal and frontal areas. The functional and anatomical organization observed within the human pulvinar was similar to the organization of the pulvinar in other primate species. SIGNIFICANCE STATEMENT The anatomical organization and basic response properties of the visual pulvinar have been extensively studied in nonhuman primates. Yet, relatively little is known about the functional and anatomical organization of the human pulvinar. Using neuroimaging, we found multiple representations of visual space within the ventral human pulvinar and extensive topographically organized connectivity with visual cortex. This organization is similar to other nonhuman primates and provides additional support that the general organization of the pulvinar is consistent across the primate phylogenetic tree. These results suggest that the human pulvinar, like other primates, is well positioned to regulate corticocortical communication. PMID:26156987

Cosmography and Data Visualization

NASA Astrophysics Data System (ADS)

Pomarède, Daniel; Courtois, Hélène M.; Hoffman, Yehuda; Tully, R. Brent

2017-05-01

Cosmography, the study and making of maps of the universe or cosmos, is a field where visual representation benefits from modern three-dimensional visualization techniques and media. At the extragalactic distance scales, visualization is contributing to our understanding of the complex structure of the local universe in terms of spatial distribution and flows of galaxies and dark matter. In this paper, we report advances in the field of extragalactic cosmography obtained using the SDvision visualization software in the context of the Cosmicflows Project. Here, multiple visualization techniques are applied to a variety of data products: catalogs of galaxy positions and galaxy peculiar velocities, reconstructed velocity field, density field, gravitational potential field, velocity shear tensor viewed in terms of its eigenvalues and eigenvectors, envelope surfaces enclosing basins of attraction. These visualizations, implemented as high-resolution images, videos, and interactive viewers, have contributed to a number of studies: the cosmography of the local part of the universe, the nature of the Great Attractor, the discovery of the boundaries of our home supercluster of galaxies Laniakea, the mapping of the cosmic web, and the study of attractors and repellers.

The role of awake craniotomy in reducing intraoperative visual field deficits during tumor surgery

PubMed Central

Wolfson, Racheal; Soni, Neil; Shah, Ashish H.; Hosein, Khadil; Sastry, Ananth; Bregy, Amade; Komotar, Ricardo J.

2015-01-01

Objective: Homonymous hemianopia due to damage to the optic radiations or visual cortex is a possible consequence of tumor resection involving the temporal or occipital lobes. The purpose of this review is to present and analyze a series of studies regarding the use of awake craniotomy (AC) to decrease visual field deficits following neurosurgery. Materials and Methods: A literature search was performed using the Medline and PubMed databases from 1970 and 2014 that compared various uses of AC other than intraoperative motor/somatosensory/language mapping with a focus on visual field mapping. Results: For the 17 patients analyzed in this study, 14 surgeries resulted in quadrantanopia, 1 in hemianopia, and 2 without visual deficits. Overall, patient satisfaction with AC was high, and AC was a means to reduce surgery-related complications and cost related with the procedure. Conclusion AC is a safe and tolerable procedure that can be used effectively to map optic radiations and the visual cortices in order to preserve visual function during resection of tumors infiltrating the temporal and occipital lobes. In the majority of cases, a homonymous hemianopia was prevented and patients were left with a quadrantanopia that did not interfere with daily function. PMID:26396597

BoreholeAR: A mobile tablet application for effective borehole database visualization using an augmented reality technology

NASA Astrophysics Data System (ADS)

Lee, Sangho; Suh, Jangwon; Park, Hyeong-Dong

2015-03-01

Boring logs are widely used in geological field studies since the data describes various attributes of underground and surface environments. However, it is difficult to manage multiple boring logs in the field as the conventional management and visualization methods are not suitable for integrating and combining large data sets. We developed an iPad application to enable its user to search the boring log rapidly and visualize them using the augmented reality (AR) technique. For the development of the application, a standard borehole database appropriate for a mobile-based borehole database management system was designed. The application consists of three modules: an AR module, a map module, and a database module. The AR module superimposes borehole data on camera imagery as viewed by the user and provides intuitive visualization of borehole locations. The map module shows the locations of corresponding borehole data on a 2D map with additional map layers. The database module provides data management functions for large borehole databases for other modules. Field survey was also carried out using more than 100,000 borehole data.

A visual salience map in the primate frontal eye field.

PubMed

Thompson, Kirk G; Bichot, Narcisse P

2005-01-01

Models of attention and saccade target selection propose that within the brain there is a topographic map of visual salience that combines bottom-up and top-down influences to identify locations for further processing. The results of a series of experiments with monkeys performing visual search tasks have identified a population of frontal eye field (FEF) visually responsive neurons that exhibit all of the characteristics of a visual salience map. The activity of these FEF neurons is not sensitive to specific features of visual stimuli; but instead, their activity evolves over time to select the target of the search array. This selective activation reflects both the bottom-up intrinsic conspicuousness of the stimuli and the top-down knowledge and goals of the viewer. The peak response within FEF specifies the target for the overt gaze shift. However, the selective activity in FEF is not in itself a motor command because the magnitude of activation reflects the relative behavioral significance of the different stimuli in the visual scene and occurs even when no saccade is made. Identifying a visual salience map in FEF validates the theoretical concept of a salience map in many models of attention. In addition, it strengthens the emerging view that FEF is not only involved in producing overt gaze shifts, but is also important for directing covert spatial attention.

NOTE: The feasibility of an infrared system for real-time visualization and mapping of ultrasound fields

NASA Astrophysics Data System (ADS)

Shaw, Adam; Nunn, John

2010-06-01

In treatment planning for ultrasound therapy, it is desirable to know the 3D structure of the ultrasound field. However, mapping an ultrasound field in 3D is very slow, with even a single planar raster scan taking typically several hours. Additionally, hydrophones that are used for field mapping are expensive and can be damaged in some therapy fields. So there is value in rapid methods which enable visualization and mapping of the ultrasound field in about 1 min. In this note we explore the feasibility of mapping the intensity distribution by measuring the temperature distribution produced in a thin sheet of absorbing material. A 0.2 mm thick acetate sheet forms a window in the wall of a water tank containing the transducer. The window is oriented at 45° to the beam axis, and the distance from the transducer to the window can be varied. The temperature distribution is measured with an infrared camera; thermal images of the inclined plane could be viewed in real time or images could be captured for later analysis and 3D field reconstruction. We conclude that infrared thermography can be used to gain qualitative information about ultrasound fields. Thermal images are easily visualized with good spatial and thermal resolutions (0.044 mm and 0.05 °C in our system). The focus and field structure such as side lobes can be identified in real time from the direct video output. 3D maps and image planes at arbitrary orientations to the beam axis can be obtained and reconstructed within a few minutes. In this note we are primarily interested in the technique for characterization of high intensity focused ultrasound (HIFU) fields, but other applications such as physiotherapy fields are also possible.

The feasibility of an infrared system for real-time visualization and mapping of ultrasound fields.

PubMed

Shaw, Adam; Nunn, John

2010-06-07

In treatment planning for ultrasound therapy, it is desirable to know the 3D structure of the ultrasound field. However, mapping an ultrasound field in 3D is very slow, with even a single planar raster scan taking typically several hours. Additionally, hydrophones that are used for field mapping are expensive and can be damaged in some therapy fields. So there is value in rapid methods which enable visualization and mapping of the ultrasound field in about 1 min. In this note we explore the feasibility of mapping the intensity distribution by measuring the temperature distribution produced in a thin sheet of absorbing material. A 0.2 mm thick acetate sheet forms a window in the wall of a water tank containing the transducer. The window is oriented at 45 degrees to the beam axis, and the distance from the transducer to the window can be varied. The temperature distribution is measured with an infrared camera; thermal images of the inclined plane could be viewed in real time or images could be captured for later analysis and 3D field reconstruction. We conclude that infrared thermography can be used to gain qualitative information about ultrasound fields. Thermal images are easily visualized with good spatial and thermal resolutions (0.044 mm and 0.05 degrees C in our system). The focus and field structure such as side lobes can be identified in real time from the direct video output. 3D maps and image planes at arbitrary orientations to the beam axis can be obtained and reconstructed within a few minutes. In this note we are primarily interested in the technique for characterization of high intensity focused ultrasound (HIFU) fields, but other applications such as physiotherapy fields are also possible.

Spatial attention improves reliability of fMRI retinotopic mapping signals in occipital and parietal cortex

PubMed Central

Bressler, David W.; Silver, Michael A.

2010-01-01

Spatial attention improves visual perception and increases the amplitude of neural responses in visual cortex. In addition, spatial attention tasks and fMRI have been used to discover topographic visual field representations in regions outside visual cortex. We therefore hypothesized that requiring subjects to attend to a retinotopic mapping stimulus would facilitate the characterization of visual field representations in a number of cortical areas. In our study, subjects attended either a central fixation point or a wedge-shaped stimulus that rotated about the fixation point. Response reliability was assessed by computing coherence between the fMRI time series and a sinusoid with the same frequency as the rotating wedge stimulus. When subjects attended to the rotating wedge instead of ignoring it, the reliability of retinotopic mapping signals increased by approximately 50% in early visual cortical areas (V1, V2, V3, V3A/B, V4) and ventral occipital cortex (VO1) and by approximately 75% in lateral occipital (LO1, LO2) and posterior parietal (IPS0, IPS1 and IPS2) cortical areas. Additionally, one 5-minute run of retinotopic mapping in the attention-to-wedge condition produced responses as reliable as the average of three to five (early visual cortex) or more than five (lateral occipital, ventral occipital, and posterior parietal cortex) attention-to-fixation runs. These results demonstrate that allocating attention to the retinotopic mapping stimulus substantially reduces the amount of scanning time needed to determine the visual field representations in occipital and parietal topographic cortical areas. Attention significantly increased response reliability in every cortical area we examined and may therefore be a general mechanism for improving the fidelity of neural representations of sensory stimuli at multiple levels of the cortical processing hierarchy. PMID:20600961

Cross-disciplinary Undergraduate Research: A Case Study in Digital Mapping, western Ireland

NASA Astrophysics Data System (ADS)

Whitmeyer, S. J.; de Paor, D. G.; Nicoletti, J.; Rivera, M.; Santangelo, B.; Daniels, J.

2008-12-01

As digital mapping technology becomes ever more advanced, field geologists spend a greater proportion of time learning digital methods relative to analyzing rocks and structures. To explore potential solutions to the time commitment implicit in learning digital field methods, we paired James Madison University (JMU) geology majors (experienced in traditional field techniques) with Worcester Polytechnic Institute (WPI) engineering students (experienced in computer applications) during a four week summer mapping project in Connemara, western Ireland. The project consisted of approximately equal parts digital field mapping (directed by the geology students), and lab-based map assembly, evaluation and formatting for virtual 3D terrains (directed by the engineering students). Students collected geologic data in the field using ruggedized handheld computers (Trimble GeoExplorer® series) with ArcPAD® software. Lab work initially focused on building geologic maps in ArcGIS® from the digital field data and then progressed to developing Google Earth-based visualizations of field data and maps. Challenges included exporting GIS data, such as locations and attributes, to KML tags for viewing in Google Earth, which we accomplished using a Linux bash script written by one of our engineers - a task outside the comfort zone of the average geology major. We also attempted to expand the scope of Google Earth by using DEMs of present-day geologically-induced landforms as representative models for paleo-geographic reconstructions of the western Ireland field area. As our integrated approach to digital field work progressed, we found that our digital field mapping produced data at a faster rate than could be effectively managed during our allotted time for lab work. This likely reflected the more developed methodology for digital field data collection, as compared with our lab-based attempts to develop new methods for 3D visualization of geologic maps. However, this experiment in cross-disciplinary undergraduate research was a big success, with an enthusiastic interchange of expertise between undergraduate geology and engineering students that produced new, cutting-edge methods for visualizing geologic data and maps.

Spatial and Global Sensory Suppression Mapping Encompassing the Central 10° Field in Anisometropic Amblyopia.

PubMed

Li, Jingjing; Li, Jinrong; Chen, Zidong; Liu, Jing; Yuan, Junpeng; Cai, Xiaoxiao; Deng, Daming; Yu, Minbin

2017-01-01

We investigate the efficacy of a novel dichoptic mapping paradigm in evaluating visual function of anisometropic amblyopes. Using standard clinical measures of visual function (visual acuity, stereo acuity, Bagolini lenses, and neutral density filters) and a novel quantitative mapping technique, 26 patients with anisometropic amblyopia (mean age = 19.15 ± 4.42 years) were assessed. Two additional psychophysical interocular suppression measurements were tested with dichoptic global motion coherence and binocular phase combination tasks. Luminance reduction was achieved by placing neutral density filters in front of the normal eye. Our study revealed that suppression changes across the central 10° visual field by mean luminance modulation in amblyopes as well as normal controls. Using simulation and an elimination of interocular suppression, we identified a novel method to effectively reflect the distribution of suppression in anisometropic amblyopia. Additionally, the new quantitative mapping technique was in good agreement with conventional clinical measures, such as interocular acuity difference (P < 0.001) and stereo acuity (P = 0.005). There was a good consistency between the results of interocular suppression with dichoptic mapping paradigm and the results of the other two psychophysical methods (suppression mapping versus binocular phase combination, P < 0.001; suppression mapping versus global motion coherence, P = 0.005). The dichoptic suppression mapping technique is an effective method to represent impaired visual function in patients with anisometropic amblyopia. It offers a potential in "micro-"antisuppression mapping tests and therapies for amblyopia.

Anosognosia for obvious visual field defects in stroke patients.

PubMed

Baier, Bernhard; Geber, Christian; Müller-Forell, Wiebke; Müller, Notger; Dieterich, Marianne; Karnath, Hans-Otto

2015-01-01

Patients with anosognosia for visual field defect (AVFD) fail to recognize consciously their visual field defect. There is still unclarity whether specific neural correlates are associated with AVFD. We studied AVFD in 54 patients with acute stroke and a visual field defect. Nineteen percent of this unselected sample showed AVFD. By using modern voxelwise lesion-behaviour mapping techniques we found an association between AVFD and parts of the lingual gyrus, the cuneus as well as the posterior cingulate and corpus callosum. Damage to these regions appears to induce unawareness of visual field defects and thus may play a significant role for conscious visual perception.

Mapping the spatial patterns of field traffic and traffic intensity to predict soil compaction risks at the field scale

NASA Astrophysics Data System (ADS)

Duttmann, Rainer; Kuhwald, Michael; Nolde, Michael

2015-04-01

Soil compaction is one of the main threats to cropland soils in present days. In contrast to easily visible phenomena of soil degradation, soil compaction, however, is obscured by other signals such as reduced crop yield, delayed crop growth, and the ponding of water, which makes it difficult to recognize and locate areas impacted by soil compaction directly. Although it is known that trafficking intensity is a key factor for soil compaction, until today only modest work has been concerned with the mapping of the spatially distributed patterns of field traffic and with the visual representation of the loads and pressures applied by farm traffic within single fields. A promising method for for spatial detection and mapping of soil compaction risks of individual fields is to process dGPS data, collected from vehicle-mounted GPS receivers and to compare the soil stress induced by farm machinery to the load bearing capacity derived from given soil map data. The application of position-based machinery data enables the mapping of vehicle movements over time as well as the assessment of trafficking intensity. It also facilitates the calculation of the trafficked area and the modeling of the loads and pressures applied to soil by individual vehicles. This paper focuses on the modeling and mapping of the spatial patterns of traffic intensity in silage maize fields during harvest, considering the spatio-temporal changes in wheel load and ground contact pressure along the loading sections. In addition to scenarios calculated for varying mechanical soil strengths, an example for visualizing the three-dimensional stress propagation inside the soil will be given, using the Visualization Toolkit (VTK) to construct 2D or 3D maps supporting to decision making due to sustainable field traffic management.

Adaptive Kalman filtering for real-time mapping of the visual field

PubMed Central

Ward, B. Douglas; Janik, John; Mazaheri, Yousef; Ma, Yan; DeYoe, Edgar A.

2013-01-01

This paper demonstrates the feasibility of real-time mapping of the visual field for clinical applications. Specifically, three aspects of this problem were considered: (1) experimental design, (2) statistical analysis, and (3) display of results. Proper experimental design is essential to achieving a successful outcome, particularly for real-time applications. A random-block experimental design was shown to have less sensitivity to measurement noise, as well as greater robustness to error in modeling of the hemodynamic impulse response function (IRF) and greater flexibility than common alternatives. In addition, random encoding of the visual field allows for the detection of voxels that are responsive to multiple, not necessarily contiguous, regions of the visual field. Due to its recursive nature, the Kalman filter is ideally suited for real-time statistical analysis of visual field mapping data. An important feature of the Kalman filter is that it can be used for nonstationary time series analysis. The capability of the Kalman filter to adapt, in real time, to abrupt changes in the baseline arising from subject motion inside the scanner and other external system disturbances is important for the success of clinical applications. The clinician needs real-time information to evaluate the success or failure of the imaging run and to decide whether to extend, modify, or terminate the run. Accordingly, the analytical software provides real-time displays of (1) brain activation maps for each stimulus segment, (2) voxel-wise spatial tuning profiles, (3) time plots of the variability of response parameters, and (4) time plots of activated volume. PMID:22100663

The Tölz Temporal Topography Study: mapping the visual field across the life span. Part I: the topography of light detection and temporal-information processing.

PubMed

Poggel, Dorothe A; Treutwein, Bernhard; Calmanti, Claudia; Strasburger, Hans

2012-08-01

Temporal performance parameters vary across the visual field. Their topographical distributions relative to each other and relative to basic visual performance measures and their relative change over the life span are unknown. Our goal was to characterize the topography and age-related change of temporal performance. We acquired visual field maps in 95 healthy participants (age: 10-90 years): perimetric thresholds, double-pulse resolution (DPR), reaction times (RTs), and letter contrast thresholds. DPR and perimetric thresholds increased with eccentricity and age; the periphery showed a more pronounced age-related increase than the center. RT increased only slightly and uniformly with eccentricity. It remained almost constant up to the age of 60, a marked change occurring only above 80. Overall, age was a poor predictor of functionality. Performance decline could be explained only in part by the aging of the retina and optic media. In Part II, we therefore examine higher visual and cognitive functions.

Efficient receptive field tiling in primate V1

PubMed Central

Nauhaus, Ian; Nielsen, Kristina J.; Callaway, Edward M.

2017-01-01

The primary visual cortex (V1) encodes a diverse set of visual features, including orientation, ocular dominance (OD) and spatial frequency (SF), whose joint organization must be precisely structured to optimize coverage within the retinotopic map. Prior experiments have only identified efficient coverage based on orthogonal maps. Here, we used two-photon calcium imaging to reveal an alternative arrangement for OD and SF maps in macaque V1; their gradients run parallel but with unique spatial periods, whereby low SF regions coincide with monocular regions. Next, we mapped receptive fields and find surprisingly precise micro-retinotopy that yields a smaller point-image and requires more efficient inter-map geometry, thus underscoring the significance of map relationships. While smooth retinotopy is constraining, studies suggest that it improves both wiring economy and the V1 population code read downstream. Altogether, these data indicate that connectivity within V1 is finely tuned and precise at the level of individual neurons. PMID:27499086

Bibliometric mapping: eight decades of analytical chemistry, with special focus on the use of mass spectrometry.

PubMed

Waaijer, Cathelijn J F; Palmblad, Magnus

2015-01-01

In this Feature we use automatic bibliometric mapping tools to visualize the history of analytical chemistry from the 1920s until the present. In particular, we have focused on the application of mass spectrometry in different fields. The analysis shows major shifts in research focus and use of mass spectrometry. We conclude by discussing the application of bibliometric mapping and visualization tools in analytical chemists' research.

Visual Field Map Clusters in High-Order Visual Processing: Organization of V3A/V3B and a New Cloverleaf Cluster in the Posterior Superior Temporal Sulcus

PubMed Central

Barton, Brian; Brewer, Alyssa A.

2017-01-01

The cortical hierarchy of the human visual system has been shown to be organized around retinal spatial coordinates throughout much of low- and mid-level visual processing. These regions contain visual field maps (VFMs) that each follows the organization of the retina, with neighboring aspects of the visual field processed in neighboring cortical locations. On a larger, macrostructural scale, groups of such sensory cortical field maps (CFMs) in both the visual and auditory systems are organized into roughly circular cloverleaf clusters. CFMs within clusters tend to share properties such as receptive field distribution, cortical magnification, and processing specialization. Here we use fMRI and population receptive field (pRF) modeling to investigate the extent of VFM and cluster organization with an examination of higher-level visual processing in temporal cortex and compare these measurements to mid-level visual processing in dorsal occipital cortex. In human temporal cortex, the posterior superior temporal sulcus (pSTS) has been implicated in various neuroimaging studies as subserving higher-order vision, including face processing, biological motion perception, and multimodal audiovisual integration. In human dorsal occipital cortex, the transverse occipital sulcus (TOS) contains the V3A/B cluster, which comprises two VFMs subserving mid-level motion perception and visuospatial attention. For the first time, we present the organization of VFMs in pSTS in a cloverleaf cluster. This pSTS cluster contains four VFMs bilaterally: pSTS-1:4. We characterize these pSTS VFMs as relatively small at ∼125 mm2 with relatively large pRF sizes of ∼2–8° of visual angle across the central 10° of the visual field. V3A and V3B are ∼230 mm2 in surface area, with pRF sizes here similarly ∼1–8° of visual angle across the same region. In addition, cortical magnification measurements show that a larger extent of the pSTS VFM surface areas are devoted to the peripheral visual field than those in the V3A/B cluster. Reliability measurements of VFMs in pSTS and V3A/B reveal that these cloverleaf clusters are remarkably consistent and functionally differentiable. Our findings add to the growing number of measurements of widespread sensory CFMs organized into cloverleaf clusters, indicating that CFMs and cloverleaf clusters may both be fundamental organizing principles in cortical sensory processing. PMID:28293182

Localization of MEG human brain responses to retinotopic visual stimuli with contrasting source reconstruction approaches

PubMed Central

Cicmil, Nela; Bridge, Holly; Parker, Andrew J.; Woolrich, Mark W.; Krug, Kristine

2014-01-01

Magnetoencephalography (MEG) allows the physiological recording of human brain activity at high temporal resolution. However, spatial localization of the source of the MEG signal is an ill-posed problem as the signal alone cannot constrain a unique solution and additional prior assumptions must be enforced. An adequate source reconstruction method for investigating the human visual system should place the sources of early visual activity in known locations in the occipital cortex. We localized sources of retinotopic MEG signals from the human brain with contrasting reconstruction approaches (minimum norm, multiple sparse priors, and beamformer) and compared these to the visual retinotopic map obtained with fMRI in the same individuals. When reconstructing brain responses to visual stimuli that differed by angular position, we found reliable localization to the appropriate retinotopic visual field quadrant by a minimum norm approach and by beamforming. Retinotopic map eccentricity in accordance with the fMRI map could not consistently be localized using an annular stimulus with any reconstruction method, but confining eccentricity stimuli to one visual field quadrant resulted in significant improvement with the minimum norm. These results inform the application of source analysis approaches for future MEG studies of the visual system, and indicate some current limits on localization accuracy of MEG signals. PMID:24904268

The Topography Tub Learning Activity

NASA Astrophysics Data System (ADS)

Glesener, G. B.

2014-12-01

Understanding the basic elements of a topographic map (i.e. contour lines and intervals) is just a small part of learning how to use this abstract representational system as a resource in geologic mapping. Interpretation of a topographic map and matching its features with real-world structures requires that the system is utilized for visualizing the shapes of these structures and their spatial orientation. To enrich students' skills in visualizing topography from topographic maps a spatial training activity has been developed that uses 3D objects of various shapes and sizes, a sighting tool, a plastic basin, water, and transparencies. In the first part of the activity, the student is asked to draw a topographic map of one of the 3D objects. Next, the student places the object into a plastic tub in which water is added to specified intervals of height. The shoreline at each interval is used to reference the location of the contour line the student draws on a plastic inkjet transparency directly above the object. A key part of this activity is the use of a sighting tool by the student to assist in keeping the pencil mark directly above the shoreline. It (1) ensures the accurate positioning of the contour line and (2) gives the learner experience with using a sight before going out into the field. Finally, after the student finishes drawing the contour lines onto the transparency, the student can compare and contrast the two maps in order to discover where improvements in their visualization of the contours can be made. The teacher and/or peers can also make suggestions on ways to improve. A number of objects with various shapes and sizes are used in this exercise to produce contour lines representing the different types of topography the student may encounter while field mapping. The intended outcome from using this visualization training activity is improvement in performance of visualizing topography as the student moves between the topographic representation and corresponding topography in the field.

Hemisphere-Dependent Attentional Modulation of Human Parietal Visual Field Representations

PubMed Central

Silver, Michael A.

2015-01-01

Posterior parietal cortex contains several areas defined by topographically organized maps of the contralateral visual field. However, recent studies suggest that ipsilateral stimuli can elicit larger responses in the right than left hemisphere within these areas, depending on task demands. Here we determined the effects of spatial attention on the set of visual field locations (the population receptive field [pRF]) that evoked a response for each voxel in human topographic parietal cortex. A two-dimensional Gaussian was used to model the pRF in each voxel, and we measured the effects of attention on not only the center (preferred visual field location) but also the size (visual field extent) of the pRF. In both hemispheres, larger pRFs were associated with attending to the mapping stimulus compared with attending to a central fixation point. In the left hemisphere, attending to the stimulus also resulted in more peripheral preferred locations of contralateral representations, compared with attending fixation. These effects of attention on both pRF size and preferred location preserved contralateral representations in the left hemisphere. In contrast, attentional modulation of pRF size but not preferred location significantly increased representation of the ipsilateral (right) visual hemifield in right parietal cortex. Thus, attention effects in topographic parietal cortex exhibit hemispheric asymmetries similar to those seen in hemispatial neglect. Our findings suggest potential mechanisms underlying the behavioral deficits associated with this disorder. PMID:25589746

A second-order orientation-contrast stimulus for population-receptive-field-based retinotopic mapping.

PubMed

Yildirim, Funda; Carvalho, Joana; Cornelissen, Frans W

2018-01-01

Visual field or retinotopic mapping is one of the most frequently used paradigms in fMRI. It uses activity evoked by position-varying high luminance contrast visual patterns presented throughout the visual field for determining the spatial organization of cortical visual areas. While the advantage of using high luminance contrast is that it tends to drive a wide range of neural populations - thus resulting in high signal-to-noise BOLD responses - this may also be a limitation, especially for approaches that attempt to squeeze more information out of the BOLD response, such as population receptive field (pRF) mapping. In that case, more selective stimulation of a subset of neurons - despite reduced signals - could result in better characterization of pRF properties. Here, we used a second-order stimulus based on local differences in orientation texture - to which we refer as orientation contrast - to perform retinotopic mapping. Participants in our experiment viewed arrays of Gabor patches composed of a foreground (a bar) and a background. These could only be distinguished on the basis of a difference in patch orientation. In our analyses, we compare the pRF properties obtained using this new orientation contrast-based retinotopy (OCR) to those obtained using classic luminance contrast-based retinotopy (LCR). Specifically, in higher order cortical visual areas such as LO, our novel approach resulted in non-trivial reductions in estimated population receptive field size of around 30%. A set of control experiments confirms that the most plausible cause for this reduction is that OCR mainly drives neurons sensitive to orientation contrast. We discuss how OCR - by limiting receptive field scatter and reducing BOLD displacement - may result in more accurate pRF localization as well. Estimation of neuronal properties is crucial for interpreting cortical function. Therefore, we conclude that using our approach, it is possible to selectively target particular neuronal populations, opening the way to use pRF modeling to dissect the response properties of more clearly-defined neuronal populations in different visual areas. Copyright © 2017 Elsevier Inc. All rights reserved.

Visual saliency in MPEG-4 AVC video stream

NASA Astrophysics Data System (ADS)

Ammar, M.; Mitrea, M.; Hasnaoui, M.; Le Callet, P.

2015-03-01

Visual saliency maps already proved their efficiency in a large variety of image/video communication application fields, covering from selective compression and channel coding to watermarking. Such saliency maps are generally based on different visual characteristics (like color, intensity, orientation, motion,…) computed from the pixel representation of the visual content. This paper resumes and extends our previous work devoted to the definition of a saliency map solely extracted from the MPEG-4 AVC stream syntax elements. The MPEG-4 AVC saliency map thus defined is a fusion of static and dynamic map. The static saliency map is in its turn a combination of intensity, color and orientation features maps. Despite the particular way in which all these elementary maps are computed, the fusion techniques allowing their combination plays a critical role in the final result and makes the object of the proposed study. A total of 48 fusion formulas (6 for combining static features and, for each of them, 8 to combine static to dynamic features) are investigated. The performances of the obtained maps are evaluated on a public database organized at IRCCyN, by computing two objective metrics: the Kullback-Leibler divergence and the area under curve.

Structural and functional correlates of visual field asymmetry in the human brain by diffusion kurtosis MRI and functional MRI.

PubMed

O'Connell, Caitlin; Ho, Leon C; Murphy, Matthew C; Conner, Ian P; Wollstein, Gadi; Cham, Rakie; Chan, Kevin C

2016-11-09

Human visual performance has been observed to show superiority in localized regions of the visual field across many classes of stimuli. However, the underlying neural mechanisms remain unclear. This study aims to determine whether the visual information processing in the human brain is dependent on the location of stimuli in the visual field and the corresponding neuroarchitecture using blood-oxygenation-level-dependent functional MRI (fMRI) and diffusion kurtosis MRI, respectively, in 15 healthy individuals at 3 T. In fMRI, visual stimulation to the lower hemifield showed stronger brain responses and larger brain activation volumes than the upper hemifield, indicative of the differential sensitivity of the human brain across the visual field. In diffusion kurtosis MRI, the brain regions mapping to the lower visual field showed higher mean kurtosis, but not fractional anisotropy or mean diffusivity compared with the upper visual field. These results suggested the different distributions of microstructural organization across visual field brain representations. There was also a strong positive relationship between diffusion kurtosis and fMRI responses in the lower field brain representations. In summary, this study suggested the structural and functional brain involvements in the asymmetry of visual field responses in humans, and is important to the neurophysiological and psychological understanding of human visual information processing.

Pattern recognition neural-net by spatial mapping of biology visual field

NASA Astrophysics Data System (ADS)

Lin, Xin; Mori, Masahiko

2000-05-01

The method of spatial mapping in biology vision field is applied to artificial neural networks for pattern recognition. By the coordinate transform that is called the complex-logarithm mapping and Fourier transform, the input images are transformed into scale- rotation- and shift- invariant patterns, and then fed into a multilayer neural network for learning and recognition. The results of computer simulation and an optical experimental system are described.

Hemispheric specialization for language according to grapho-phonemic transformation and gender. A divided visual field experiment.

PubMed

Cousin, Emilie; Perrone, Marcela; Baciu, Monica

2009-04-01

This behavioral study aimed at assessing the effect of two variables on the degree of hemispheric specialization for language. One of them was the grapho-phonemic translation (transformation) (letter-sound mapping) and the other was the participants'gender. The experiment was conducted with healthy volunteers. A divided visual field procedure has been used to perform a phoneme detection task implying either regular (transparent) grapho-phonemic translation (letter-sound mapping consistency) or irregular (non-transparent) grapho-phonemic translation (letter-sound mapping inconsistency). Our results reveal a significant effect of grapho-phonemic translation on the degree of hemispheric dominance for language. The phoneme detection on items with transparent translation (TT) was performed faster than phoneme detection on items with non-transparent translation (NTT). This effect seems to be due to faster identification of TT than NTT when the items were presented in the left visual field (LVF)-right hemisphere (RH). There was no difference between TT and NTT for stimuli presented in the right visual field (RVF)-left hemisphere (LH). This result suggests that grapho-phonemic translation or the degree of transparency can affect the degree of hemispheric specialization, by modulating the right hemisphere activity. With respect to gender, male participants were significantly more lateralized than female participants but no interaction was observed between gender and degree of transparency.

Attention modulates spatial priority maps in the human occipital, parietal and frontal cortices

PubMed Central

Sprague, Thomas C.; Serences, John T.

2014-01-01

Computational theories propose that attention modulates the topographical landscape of spatial ‘priority’ maps in regions of visual cortex so that the location of an important object is associated with higher activation levels. While single-unit recording studies have demonstrated attention-related increases in the gain of neural responses and changes in the size of spatial receptive fields, the net effect of these modulations on the topography of region-level priority maps has not been investigated. Here, we used fMRI and a multivariate encoding model to reconstruct spatial representations of attended and ignored stimuli using activation patterns across entire visual areas. These reconstructed spatial representations reveal the influence of attention on the amplitude and size of stimulus representations within putative priority maps across the visual hierarchy. Our results suggest that attention increases the amplitude of stimulus representations in these spatial maps, particularly in higher visual areas, but does not substantively change their size. PMID:24212672

Mapping multisensory parietal face and body areas in humans.

PubMed

Huang, Ruey-Song; Chen, Ching-fu; Tran, Alyssa T; Holstein, Katie L; Sereno, Martin I

2012-10-30

Detection and avoidance of impending obstacles is crucial to preventing head and body injuries in daily life. To safely avoid obstacles, locations of objects approaching the body surface are usually detected via the visual system and then used by the motor system to guide defensive movements. Mediating between visual input and motor output, the posterior parietal cortex plays an important role in integrating multisensory information in peripersonal space. We used functional MRI to map parietal areas that see and feel multisensory stimuli near or on the face and body. Tactile experiments using full-body air-puff stimulation suits revealed somatotopic areas of the face and multiple body parts forming a higher-level homunculus in the superior posterior parietal cortex. Visual experiments using wide-field looming stimuli revealed retinotopic maps that overlap with the parietal face and body areas in the postcentral sulcus at the most anterior border of the dorsal visual pathway. Starting at the parietal face area and moving medially and posteriorly into the lower-body areas, the median of visual polar-angle representations in these somatotopic areas gradually shifts from near the horizontal meridian into the lower visual field. These results suggest the parietal face and body areas fuse multisensory information in peripersonal space to guard an individual from head to toe.

Unsupervised spatiotemporal analysis of fMRI data using graph-based visualizations of self-organizing maps.

PubMed

Katwal, Santosh B; Gore, John C; Marois, Rene; Rogers, Baxter P

2013-09-01

We present novel graph-based visualizations of self-organizing maps for unsupervised functional magnetic resonance imaging (fMRI) analysis. A self-organizing map is an artificial neural network model that transforms high-dimensional data into a low-dimensional (often a 2-D) map using unsupervised learning. However, a postprocessing scheme is necessary to correctly interpret similarity between neighboring node prototypes (feature vectors) on the output map and delineate clusters and features of interest in the data. In this paper, we used graph-based visualizations to capture fMRI data features based upon 1) the distribution of data across the receptive fields of the prototypes (density-based connectivity); and 2) temporal similarities (correlations) between the prototypes (correlation-based connectivity). We applied this approach to identify task-related brain areas in an fMRI reaction time experiment involving a visuo-manual response task, and we correlated the time-to-peak of the fMRI responses in these areas with reaction time. Visualization of self-organizing maps outperformed independent component analysis and voxelwise univariate linear regression analysis in identifying and classifying relevant brain regions. We conclude that the graph-based visualizations of self-organizing maps help in advanced visualization of cluster boundaries in fMRI data enabling the separation of regions with small differences in the timings of their brain responses.

Visual analytics as a translational cognitive science.

PubMed

Fisher, Brian; Green, Tera Marie; Arias-Hernández, Richard

2011-07-01

Visual analytics is a new interdisciplinary field of study that calls for a more structured scientific approach to understanding the effects of interaction with complex graphical displays on human cognitive processes. Its primary goal is to support the design and evaluation of graphical information systems that better support cognitive processes in areas as diverse as scientific research and emergency management. The methodologies that make up this new field are as yet ill defined. This paper proposes a pathway for development of visual analytics as a translational cognitive science that bridges fundamental research in human/computer cognitive systems and design and evaluation of information systems in situ. Achieving this goal will require the development of enhanced field methods for conceptual decomposition of human/computer cognitive systems that maps onto laboratory studies, and improved methods for conducting laboratory investigations that might better map onto real-world cognitive processes in technology-rich environments. Copyright © 2011 Cognitive Science Society, Inc.

Hemispheric Specialization for Language According to Grapho-Phonemic Transformation and Gender. A Divided Visual Field Experiment

ERIC Educational Resources Information Center

Cousin, Emilie; Perrone, Marcela; Baciu, Monica

2009-01-01

This behavioral study aimed at assessing the effect of two variables on the degree of hemispheric specialization for language. One of them was the "grapho-phonemic translation (transformation)" (letter-sound mapping) and the other was the participants' "gender". The experiment was conducted with healthy volunteers. A divided visual field procedure…

Mapping the Visual Communication Field.

ERIC Educational Resources Information Center

Moriarty, Sandra E.

This paper discusses visual communication theory. After an examination of the literature, this study built a more extensive bibliography of visual communication in general--theory, research, teaching--as well as a taxonomy that was better grounded. A 95-page bibliography was developed for works from a number of scholarly journals dealing with…

IdentityMap Visualization of the Super Identity Model

ScienceCinema

None

2018-06-08

The Super Identity Model is a collaboration with six United Kingdom universities to develop use cases used to piece together a person's identity across biological, cyber, psychological, and biographical domains. PNNL visualized the model in a web-based application called IdentityMap. This is the first step in a promising new field of research. Interested future collaborators are welcome to find out more by emailing superid@pnnl.gov.

IdentityMap Visualization of the Super Identity Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

The Super Identity Model is a collaboration with six United Kingdom universities to develop use cases used to piece together a person's identity across biological, cyber, psychological, and biographical domains. PNNL visualized the model in a web-based application called IdentityMap. This is the first step in a promising new field of research. Interested future collaborators are welcome to find out more by emailing superid@pnnl.gov.

Structural and Functional Correlates of Visual Field Asymmetry in the Human Brain by Diffusion Kurtosis MRI and Functional MRI

PubMed Central

O’Connell, Caitlin; Ho, Leon C.; Murphy, Matthew C.; Conner, Ian P.; Wollstein, Gadi; Cham, Rakie; Chan, Kevin C.

2016-01-01

Human visual performance has been observed to exhibit superiority in localized regions of the visual field across many classes of stimuli. However, the underlying neural mechanisms remain unclear. This study aims to determine if the visual information processing in the human brain is dependent on the location of stimuli in the visual field and the corresponding neuroarchitecture using blood-oxygenation-level-dependent functional MRI (fMRI) and diffusion kurtosis MRI (DKI), respectively in 15 healthy individuals at 3 Tesla. In fMRI, visual stimulation to the lower hemifield showed stronger brain responses and larger brain activation volumes than the upper hemifield, indicative of the differential sensitivity of the human brain across the visual field. In DKI, the brain regions mapping to the lower visual field exhibited higher mean kurtosis but not fractional anisotropy or mean diffusivity when compared to the upper visual field. These results suggested the different distributions of microstructural organization across visual field brain representations. There was also a strong positive relationship between diffusion kurtosis and fMRI responses in the lower field brain representations. In summary, this study suggested the structural and functional brain involvements in the asymmetry of visual field responses in humans, and is important to the neurophysiological and psychological understanding of human visual information processing. PMID:27631541

Discussion on the 3D visualizing of 1:200 000 geological map

NASA Astrophysics Data System (ADS)

Wang, Xiaopeng

2018-01-01

Using United States National Aeronautics and Space Administration Shuttle Radar Topography Mission (SRTM) terrain data as digital elevation model (DEM), overlap scanned 1:200 000 scale geological map, program using Direct 3D of Microsoft with C# computer language, the author realized the three-dimensional visualization of the standard division geological map. User can inspect the regional geology content with arbitrary angle, rotating, roaming, and can examining the strata synthetical histogram, map section and legend at any moment. This will provide an intuitionistic analyzing tool for the geological practitioner to do structural analysis with the assistant of landform, dispose field exploration route etc.

Mapping scientific frontiers : the quest for knowledge visualization.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boyack, Kevin W.

Visualization of scientific frontiers is a relatively new field, yet it has a long history and many predecessors. The application of science to science itself has been undertaken for decades with notable early contributions by Derek Price, Thomas Kuhn, Diana Crane, Eugene Garfield, and many others. What is new is the field of information visualization and application of its techniques to help us understand the process of science in the making. In his new book, Chaomei Chen takes us on a journey through this history, touching on predecessors, and then leading us firmly into the new world of Mapping Scientificmore » Frontiers. Building on the foundation of his earlier book, Information Visualization and Virtual Environments, Chen's new offering is much less a tutorial in how to do information visualization, and much more a conceptual exploration of why and how the visualization of science can change the way we do science, amplified by real examples. Chen's stated intents for the book are: (1) to focus on principles of visual thinking that enable the identification of scientific frontiers; (2) to introduce a way to systematize the identification of scientific frontiers (or paradigms) through visualization techniques; and (3) to stimulate interdisciplinary research between information visualization and information science researchers. On all these counts, he succeeds. Chen's book can be broken into two parts which focus on the first two purposes stated above. The first, consisting of the initial four chapters, covers history and predecessors. Kuhn's theory of normal science punctuated by periods of revolution, now commonly known as paradigm shifts, motivates the work. Relevant predecessors outside the traditional field of information science such as cartography (both terrestrial and celestial), mapping the mind, and principles of visual association and communication, are given ample coverage. Chen also describes enabling techniques known to information scientists, such as multi-dimensional scaling, advanced dimensional reduction, social network analysis, Pathfinder network scaling, and landscape visualizations. No algorithms are given here; rather, these techniques are described from the point of view of enabling 'visual thinking'. The Generalized Similarity Analysis (GSA) technique used by Chen in his recent published papers is also introduced here. Information and computer science professionals would be wise not to skip through these early chapters. Although principles of gestalt psychology, cartography, thematic maps, and association techniques may be outside their technology comfort zone, or interest, these predecessors lay a groundwork for the 'visual thinking' that is required to create effective visualizations. Indeed, the great challenge in information visualization is to transform the abstract and intangible into something visible, concrete, and meaningful to the user. The second part of the book, covering the final three chapters, extends the mapping metaphor into the realm of scientific discovery through the structuring of literatures in a way that enables us to see scientific frontiers or paradigms. Case studies are used extensively to show the logical progression that has been made in recent years to get us to this point. Homage is paid to giants of the last 20 years including Michel Callon for co-word mapping, Henry Small for document co-citation analysis and specialty narratives (charting a path linking the different sciences), and Kate McCain for author co-citation analysis, whose work has led to the current state-of-the-art. The last two chapters finally answer the question - 'What does a scientific paradigm look like?' The visual answer given is specific to the GSA technique used by Chen, but does satisfy the intent of the book - to introduce a way to visually identify scientific frontiers. A variety of case studies, mostly from Chen's previously published work - supermassive black holes, cross-domain applications of Pathfinder networks, mass extinction debates, impact of Don Swanson's work, and mad cow disease and vCJD in humans - succeed in explaining how visualization can be used to show the development of, competition between, and eventual acceptance (or replacement) of scientific paradigms. Although not addressed specifically, Chen's work nonetheless makes the persuasive argument that visual maps alone are not sufficient to explain 'the making of science' to a non-expert in a particular field. Rather, expert knowledge is still required to interpret these maps and to explain the paradigms. This combination of visual maps and expert knowledge, used jointly to good effect in the book, becomes a potent means for explaining progress in science to the expert and non-expert alike. Work to extend the GSA technique to explore latent domain knowledge (important work that falls below the citation thresholds typically used in GSA) is also explored here.« less

Comparison of Diagnostic Accuracy between Octopus 900 and Goldmann Kinetic Visual Fields

PubMed Central

Rowe, Fiona J.; Rowlands, Alison

2014-01-01

Purpose. To determine diagnostic accuracy of kinetic visual field assessment by Octopus 900 perimetry compared with Goldmann perimetry. Methods. Prospective cross section evaluation of 40 control subjects with full visual fields and 50 patients with known visual field loss. Comparison of test duration and area measurement of isopters for Octopus 3, 5, and 10°/sec stimulus speeds. Comparison of test duration and type of visual field classification for Octopus versus Goldmann perimetry. Results were independently graded for presence/absence of field defect and for type and location of defect. Statistical evaluation comprised of ANOVA and paired t test for evaluation of parametric data with Bonferroni adjustment. Bland Altman and Kappa tests were used for measurement of agreement between data. Results. Octopus 5°/sec perimetry had comparable test duration to Goldmann perimetry. Octopus perimetry reliably detected type and location of visual field loss with visual fields matched to Goldmann results in 88.8% of results (K = 0.775). Conclusions. Kinetic perimetry requires individual tailoring to ensure accuracy. Octopus perimetry was reproducible for presence/absence of visual field defect. Our screening protocol when using Octopus perimetry is 5°/sec for determining boundaries of peripheral isopters and 3°/sec for blind spot mapping with further evaluation of area of field loss for defect depth and size. PMID:24587983

A Web-based Visualization System for Three Dimensional Geological Model using Open GIS

NASA Astrophysics Data System (ADS)

Nemoto, T.; Masumoto, S.; Nonogaki, S.

2017-12-01

A three dimensional geological model is an important information in various fields such as environmental assessment, urban planning, resource development, waste management and disaster mitigation. In this study, we have developed a web-based visualization system for 3D geological model using free and open source software. The system has been successfully implemented by integrating web mapping engine MapServer and geographic information system GRASS. MapServer plays a role of mapping horizontal cross sections of 3D geological model and a topographic map. GRASS provides the core components for management, analysis and image processing of the geological model. Online access to GRASS functions has been enabled using PyWPS that is an implementation of WPS (Web Processing Service) Open Geospatial Consortium (OGC) standard. The system has two main functions. Two dimensional visualization function allows users to generate horizontal and vertical cross sections of 3D geological model. These images are delivered via WMS (Web Map Service) and WPS OGC standards. Horizontal cross sections are overlaid on the topographic map. A vertical cross section is generated by clicking a start point and an end point on the map. Three dimensional visualization function allows users to visualize geological boundary surfaces and a panel diagram. The user can visualize them from various angles by mouse operation. WebGL is utilized for 3D visualization. WebGL is a web technology that brings hardware-accelerated 3D graphics to the browser without installing additional software. The geological boundary surfaces can be downloaded to incorporate the geologic structure in a design on CAD and model for various simulations. This study was supported by JSPS KAKENHI Grant Number JP16K00158.

Arrowland v1.0

DOE Office of Scientific and Technical Information (OSTI.GOV)

BIRKEL, GARRETT; GARCIA MARTIN, HECTOR; MORRELL, WILLIAM

"Arrowland" is a web-based software application primarily for mapping, integrating and visualizing a variety of metabolism data of living organisms, including but not limited to metabolomics, proteomics, transcriptomics and fluxomics. This software application makes multi-omics data analysis intuitive and interactive. It improves data sharing and communication by enabling users to visualize their omics data using a web browser (on a PC or mobile device). It increases user's productivity by simplifying multi-omics data analysis using well developed maps as a guide. Users using this tool can gain insights into their data sets that would be difficult or even impossible to teasemore » out by looking at raw number, or using their currently existing toolchains to generate static single-use maps. Arrowland helps users save time by visualizing relative changes in different conditions or over time, and helps users to produce more significant insights faster. Preexisting maps decrease the learning curve for beginners in the omics field. Sets of multi-omics data are presented in the browser, as a two-dimensional flowchart resembling a map, with varying levels of detail information, based on the scaling of the map. Users can pan and zoom to explore different maps, compare maps, upload their own research data sets onto desired maps, alter map appearance in ways that facilitate interpretation, visualization and analysis of the given data, and export data, reports and actionable items to help the user initiative.« less

A low-cost and versatile system for projecting wide-field visual stimuli within fMRI scanners

PubMed Central

Greco, V.; Frijia, F.; Mikellidou, K.; Montanaro, D.; Farini, A.; D’Uva, M.; Poggi, P.; Pucci, M.; Sordini, A.; Morrone, M. C.; Burr, D. C.

2016-01-01

We have constructed and tested a custom-made magnetic-imaging-compatible visual projection system designed to project on a very wide visual field (~80°). A standard projector was modified with a coupling lens, projecting images into the termination of an image fiber. The other termination of the fiber was placed in the 3-T scanner room with a projection lens, which projected the images relayed by the fiber onto a screen over the head coil, viewed by a participant wearing magnifying goggles. To validate the system, wide-field stimuli were presented in order to identify retinotopic visual areas. The results showed that this low-cost and versatile optical system may be a valuable tool to map visual areas in the brain that process peripheral receptive fields. PMID:26092392

Cortical Cartography and Caret Software

PubMed Central

Van Essen, David C.

2011-01-01

Caret software is widely used for analyzing and visualizing many types of fMRI data, often in conjunction with experimental data from other modalities. This article places Caret’s development in a historical context that spans three decades of brain mapping – from the early days of manually generated flat maps to the nascent field of human connectomics. It also highlights some of Caret’s distinctive capabilities. This includes the ease of visualizing data on surfaces and/or volumes and on atlases as well as individual subjects. Caret can display many types of experimental data using various combinations of overlays (e.g., fMRI activation maps, cortical parcellations, areal boundaries), and it has other features that facilitate the analysis and visualization of complex neuroimaging datasets. PMID:22062192

Correspondence between retinotopic cortical mapping and conventional functional and morphological assessment of retinal disease.

PubMed

Ritter, Markus; Hummer, Allan; Ledolter, Anna A; Holder, Graham E; Windischberger, Christian; Schmidt-Erfurth, Ursula M

2018-04-26

The present study describes retinotopic mapping of the primary visual cortex using functional MRI (fMRI) in patients with retinal disease. It addresses the relationship between fMRI data and data obtained by conventional assessment including microperimetry (MP) and structural imaging. Initial testing involved eight patients with central retinal disease (Stargardt disease, STGD) and eight with peripheral retinal disease (retinitis pigmentosa, RP), who were examined using fMRI and MP (Nidek MP-1). All had a secure clinical diagnosis supported by electrophysiological data. fMRI used population-receptive field (pRF) mapping to provide retinotopic data that were then compared with the results of MP, optical coherence tomography and fundus autofluorescence imaging. Full analysis, following assessment of fMRI data reliability criteria, was performed in five patients with STGD and seven patients with RP; unstable fixation was responsible for unreliable pRF measurements in three patients excluded from final analysis. The macular regions in patients with STGD with central visual field defects and outer retinal atrophy (ORA) at the macula correlated well with pRF coverage maps showing reduced density of activated voxels at the occipital pole. Patients with RP exhibited peripheral ORA and concentric visual field defects both on MP and pRF mapping. Anterior V1 voxels, corresponding to peripheral regions, showed no significant activation. Correspondence between MP and pRF mapping was quantified by calculating the simple matching coefficient. Retinotopic maps acquired by fMRI provide a valuable adjunct in the assessment of retinal dysfunction. The addition of microperimetric data to pRF maps allowed better assessment of macular function than MP alone. Unlike MP, pRF mapping provides objective data independent of psychophysical perception from the patient. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Visual cortex in aging and Alzheimer's disease: changes in visual field maps and population receptive fields

PubMed Central

Brewer, Alyssa A.; Barton, Brian

2012-01-01

Although several studies have suggested that cortical alterations underlie such age-related visual deficits as decreased acuity, little is known about what changes actually occur in visual cortex during healthy aging. Two recent studies showed changes in primary visual cortex (V1) during normal aging; however, no studies have characterized the effects of aging on visual cortex beyond V1, important measurements both for understanding the aging process and for comparison to changes in age-related diseases. Similarly, there is almost no information about changes in visual cortex in Alzheimer's disease (AD), the most common form of dementia. Because visual deficits are often reported as one of the first symptoms of AD, measurements of such changes in the visual cortex of AD patients might improve our understanding of how the visual system is affected by neurodegeneration as well as aid early detection, accurate diagnosis and timely treatment of AD. Here we use fMRI to first compare the visual field map (VFM) organization and population receptive fields (pRFs) between young adults and healthy aging subjects for occipital VFMs V1, V2, V3, and hV4. Healthy aging subjects do not show major VFM organizational deficits, but do have reduced surface area and increased pRF sizes in the foveal representations of V1, V2, and hV4 relative to healthy young control subjects. These measurements are consistent with behavioral deficits seen in healthy aging. We then demonstrate the feasibility and first characterization of these measurements in two patients with mild AD, which reveal potential changes in visual cortex as part of the pathophysiology of AD. Our data aid in our understanding of the changes in the visual processing pathways in normal aging and provide the foundation for future research into earlier and more definitive detection of AD. PMID:24570669

Threshold and variability properties of matrix frequency-doubling technology and standard automated perimetry in glaucoma.

PubMed

Artes, Paul H; Hutchison, Donna M; Nicolela, Marcelo T; LeBlanc, Raymond P; Chauhan, Balwantray C

2005-07-01

To compare test results from second-generation Frequency-Doubling Technology perimetry (FDT2, Humphrey Matrix; Carl-Zeiss Meditec, Dublin, CA) and standard automated perimetry (SAP) in patients with glaucoma. Specifically, to examine the relationship between visual field sensitivity and test-retest variability and to compare total and pattern deviation probability maps between both techniques. Fifteen patients with glaucoma who had early to moderately advanced visual field loss with SAP (mean MD, -4.0 dB; range, +0.2 to -16.1) were enrolled in the study. Patients attended three sessions. During each session, one eye was examined twice with FDT2 (24-2 threshold test) and twice with SAP (Swedish Interactive Threshold Algorithm [SITA] Standard 24-2 test), in random order. We compared threshold values between FDT2 and SAP at test locations with similar visual field coordinates. Test-retest variability, established in terms of test-retest intervals and standard deviations (SDs), was investigated as a function of visual field sensitivity (estimated by baseline threshold and mean threshold, respectively). The magnitude of visual field defects apparent in total and pattern deviation probability maps were compared between both techniques by ordinal scoring. The global visual field indices mean deviation (MD) and pattern standard deviation (PSD) of FDT2 and SAP correlated highly (r > 0.8; P < 0.001). At test locations with high sensitivity (>25 dB with SAP), threshold estimates from FDT2 and SAP exhibited a close, linear relationship, with a slope of approximately 2.0. However, at test locations with lower sensitivity, the relationship was much weaker and ceased to be linear. In comparison with FDT2, SAP showed a slightly larger proportion of test locations with absolute defects (3.0% vs. 2.2% with SAP and FDT2, respectively, P < 0.001). Whereas SAP showed a significant increase in test-retest variability at test locations with lower sensitivity (P < 0.001), there was no relationship between variability and sensitivity with FDT2 (P = 0.46). In comparison with SAP, FDT2 exhibited narrower test-retest intervals at test locations with lower sensitivity (SAP thresholds <25 dB). A comparison of the total and pattern deviation maps between both techniques showed that the total deviation analyses of FDT2 may slightly underestimate the visual field loss apparent with SAP. However, the pattern-deviation maps of both instruments agreed well with each other. The test-retest variability of FDT2 is uniform over the measurement range of the instrument. These properties may provide advantages for the monitoring of patients with glaucoma that should be investigated in longitudinal studies.

Mapping Surface Features Produced by an Active Landslide

NASA Astrophysics Data System (ADS)

Parise, Mario; Gueguen, Erwan; Vennari, Carmela

2016-10-01

A large landslide reactivated on December 2013, at Montescaglioso, southern Italy, after 56 hours of rainfall. The landslide disrupted over 500 m of a freeway, involved a few warehouses, a supermarket, and private homes. After the event, it has been performed field surveys, aided by visual analysis of terrestrial and helicopter photographs, to compile a map of the surface deformations. The geomorphological features mapped included single fractures, sets of fractures, tension cracks, trenches, and pressure ridges. In this paper we present the methodology used, the map obtained through the intensive field work, and discuss the main surface features produced by the landslide.

Geoscience data visualization and analysis using GeoMapApp

NASA Astrophysics Data System (ADS)

Ferrini, Vicki; Carbotte, Suzanne; Ryan, William; Chan, Samantha

2013-04-01

Increased availability of geoscience data resources has resulted in new opportunities for developing visualization and analysis tools that not only promote data integration and synthesis, but also facilitate quantitative cross-disciplinary access to data. Interdisciplinary investigations, in particular, frequently require visualizations and quantitative access to specialized data resources across disciplines, which has historically required specialist knowledge of data formats and software tools. GeoMapApp (www.geomapapp.org) is a free online data visualization and analysis tool that provides direct quantitative access to a wide variety of geoscience data for a broad international interdisciplinary user community. While GeoMapApp provides access to online data resources, it can also be packaged to work offline through the deployment of a small portable hard drive. This mode of operation can be particularly useful during field programs to provide functionality and direct access to data when a network connection is not possible. Hundreds of data sets from a variety of repositories are directly accessible in GeoMapApp, without the need for the user to understand the specifics of file formats or data reduction procedures. Available data include global and regional gridded data, images, as well as tabular and vector datasets. In addition to basic visualization and data discovery functionality, users are provided with simple tools for creating customized maps and visualizations and to quantitatively interrogate data. Specialized data portals with advanced functionality are also provided for power users to further analyze data resources and access underlying component datasets. Users may import and analyze their own geospatial datasets by loading local versions of geospatial data and can access content made available through Web Feature Services (WFS) and Web Map Services (WMS). Once data are loaded in GeoMapApp, a variety options are provided to export data and/or 2D/3D visualizations into common formats including grids, images, text files, spreadsheets, etc. Examples of interdisciplinary investigations that make use of GeoMapApp visualization and analysis functionality will be provided.

Can Probability Maps of Swept-Source Optical Coherence Tomography Predict Visual Field Changes in Preperimetric Glaucoma?

PubMed

Lee, Won June; Kim, Young Kook; Jeoung, Jin Wook; Park, Ki Ho

2017-12-01

To determine the usefulness of swept-source optical coherence tomography (SS-OCT) probability maps in detecting locations with significant reduction in visual field (VF) sensitivity or predicting future VF changes, in patients with classically defined preperimetric glaucoma (PPG). Of 43 PPG patients, 43 eyes were followed-up on every 6 months for at least 2 years were analyzed in this longitudinal study. The patients underwent wide-field SS-OCT scanning and standard automated perimetry (SAP) at the time of enrollment. With this wide-scan protocol, probability maps originating from the corresponding thickness map and overlapped with SAP VF test points could be generated. We evaluated the vulnerable VF points with SS-OCT probability maps as well as the prevalence of locations with significant VF reduction or subsequent VF changes observed in the corresponding damaged areas of the probability maps. The vulnerable VF points were shown in superior and inferior arcuate patterns near the central fixation. In 19 of 43 PPG eyes (44.2%), significant reduction in baseline VF was detected within the areas of structural change on the SS-OCT probability maps. In 16 of 43 PPG eyes (37.2%), subsequent VF changes within the areas of SS-OCT probability map change were observed over the course of the follow-up. Structural changes on SS-OCT probability maps could detect or predict VF changes using SAP, in a considerable number of PPG eyes. Careful comparison of probability maps with SAP results could be useful in diagnosing and monitoring PPG patients in the clinical setting.

Estimation of cortical magnification from positional error in normally sighted and amblyopic subjects

PubMed Central

Hussain, Zahra; Svensson, Carl-Magnus; Besle, Julien; Webb, Ben S.; Barrett, Brendan T.; McGraw, Paul V.

2015-01-01

We describe a method for deriving the linear cortical magnification factor from positional error across the visual field. We compared magnification obtained from this method between normally sighted individuals and amblyopic individuals, who receive atypical visual input during development. The cortical magnification factor was derived for each subject from positional error at 32 locations in the visual field, using an established model of conformal mapping between retinal and cortical coordinates. Magnification of the normally sighted group matched estimates from previous physiological and neuroimaging studies in humans, confirming the validity of the approach. The estimate of magnification for the amblyopic group was significantly lower than the normal group: by 4.4 mm deg−1 at 1° eccentricity, assuming a constant scaling factor for both groups. These estimates, if correct, suggest a role for early visual experience in establishing retinotopic mapping in cortex. We discuss the implications of altered cortical magnification for cortical size, and consider other neural changes that may account for the amblyopic results. PMID:25761341

Attention Priority Map of Face Images in Human Early Visual Cortex.

PubMed

Mo, Ce; He, Dongjun; Fang, Fang

2018-01-03

Attention priority maps are topographic representations that are used for attention selection and guidance of task-related behavior during visual processing. Previous studies have identified attention priority maps of simple artificial stimuli in multiple cortical and subcortical areas, but investigating neural correlates of priority maps of natural stimuli is complicated by the complexity of their spatial structure and the difficulty of behaviorally characterizing their priority map. To overcome these challenges, we reconstructed the topographic representations of upright/inverted face images from fMRI BOLD signals in human early visual areas primary visual cortex (V1) and the extrastriate cortex (V2 and V3) based on a voxelwise population receptive field model. We characterized the priority map behaviorally as the first saccadic eye movement pattern when subjects performed a face-matching task relative to the condition in which subjects performed a phase-scrambled face-matching task. We found that the differential first saccadic eye movement pattern between upright/inverted and scrambled faces could be predicted from the reconstructed topographic representations in V1-V3 in humans of either sex. The coupling between the reconstructed representation and the eye movement pattern increased from V1 to V2/3 for the upright faces, whereas no such effect was found for the inverted faces. Moreover, face inversion modulated the coupling in V2/3, but not in V1. Our findings provide new evidence for priority maps of natural stimuli in early visual areas and extend traditional attention priority map theories by revealing another critical factor that affects priority maps in extrastriate cortex in addition to physical salience and task goal relevance: image configuration. SIGNIFICANCE STATEMENT Prominent theories of attention posit that attention sampling of visual information is mediated by a series of interacting topographic representations of visual space known as attention priority maps. Until now, neural evidence of attention priority maps has been limited to studies involving simple artificial stimuli and much remains unknown about the neural correlates of priority maps of natural stimuli. Here, we show that attention priority maps of face stimuli could be found in primary visual cortex (V1) and the extrastriate cortex (V2 and V3). Moreover, representations in extrastriate visual areas are strongly modulated by image configuration. These findings extend our understanding of attention priority maps significantly by showing that they are modulated, not only by physical salience and task-goal relevance, but also by the configuration of stimuli images. Copyright © 2018 the authors 0270-6474/18/380149-09$15.00/0.

Semantic Data And Visualization Techniques Applied To Geologic Field Mapping

NASA Astrophysics Data System (ADS)

Houser, P. I. Q.; Royo-Leon, M.; Munoz, R.; Estrada, E.; Villanueva-Rosales, N.; Pennington, D. D.

2015-12-01

Geologic field mapping involves the use of technology before, during, and after visiting a site. Geologists utilize hardware such as Global Positioning Systems (GPS) connected to mobile computing platforms such as tablets that include software such as ESRI's ArcPad and other software to produce maps and figures for a final analysis and report. Hand written field notes contain important information and drawings or sketches of specific areas within the field study. Our goal is to collect and geo-tag final and raw field data into a cyber-infrastructure environment with an ontology that allows for large data processing, visualization, sharing, and searching, aiding in connecting field research with prior research in the same area and/or aid with experiment replication. Online searches of a specific field area return results such as weather data from NOAA and QuakeML seismic data from USGS. These results that can then be saved to a field mobile device and searched while in the field where there is no Internet connection. To accomplish this we created the GeoField ontology service using the Web Ontology Language (OWL) and Protégé software. Advanced queries on the dataset can be made using reasoning capabilities can be supported that go beyond a standard database service. These improvements include the automated discovery of data relevant to a specific field site and visualization techniques aimed at enhancing analysis and collaboration while in the field by draping data over mobile views of the site using augmented reality. A case study is being performed at University of Texas at El Paso's Indio Mountains Research Station located near Van Horn, Texas, an active multi-disciplinary field study site. The user can interactively move the camera around the study site and view their data digitally. Geologist's can check their data against the site in real-time and improve collaboration with another person as both parties have the same interactive view of the data.

Dynamic plasticity in coupled avian midbrain maps

NASA Astrophysics Data System (ADS)

Atwal, Gurinder Singh

2004-12-01

Internal mapping of the external environment is carried out using the receptive fields of topographic neurons in the brain, and in a normal barn owl the aural and visual subcortical maps are aligned from early experiences. However, instantaneous misalignment of the aural and visual stimuli has been observed to result in adaptive behavior, manifested by functional and anatomical changes of the auditory processing system. Using methods of information theory and statistical mechanics a model of the adaptive dynamics of the aural receptive field is presented and analyzed. The dynamics is determined by maximizing the mutual information between the neural output and the weighted sensory neural inputs, admixed with noise, subject to biophysical constraints. The reduced costs of neural rewiring, as in the case of young barn owls, reveal two qualitatively different types of receptive field adaptation depending on the magnitude of the audiovisual misalignment. By letting the misalignment increase with time, it is shown that the ability to adapt can be increased even when neural rewiring costs are high, in agreement with recent experimental reports of the increased plasticity of the auditory space map in adult barn owls due to incremental learning. Finally, a critical speed of misalignment is identified, demarcating the crossover from adaptive to nonadaptive behavior.

Interacting Compasses

ERIC Educational Resources Information Center

Riveros, Hector G.; Betancourt, Julian

2009-01-01

The use of multiple compasses to map and visualize magnetic fields is well-known. The magnetic field exerts a torque on the compasses aligning them along the lines of force. Some science museums show the field of a magnet using a table with many compasses in a closely packed arrangement. However, the very interesting interactions that occur…

Semantic bifurcated importance field visualization

NASA Astrophysics Data System (ADS)

Lindahl, Eric; Petrov, Plamen

2007-04-01

While there are many good ways to map sensual reality to two dimensional displays, mapping non-physical and possibilistic information can be challenging. The advent of faster-than-real-time systems allow the predictive and possibilistic exploration of important factors that can affect the decision maker. Visualizing a compressed picture of the past and possible factors can assist the decision maker summarizing information in a cognitive based model thereby reducing clutter and perhaps related decision times. Our proposed semantic bifurcated importance field visualization uses saccadic eye motion models to partition the display into a possibilistic and sensed data vertically and spatial and semantic data horizontally. Saccadic eye movement precedes and prepares decision makers before nearly every directed action. Cognitive models for saccadic eye movement show that people prefer lateral to vertical saccadic movement. Studies have suggested that saccades may be coupled to momentary problem solving strategies. Also, the central 1.5 degrees of the visual field represents 100 times greater resolution that then peripheral field so concentrating factors can reduce unnecessary saccades. By packing information according to saccadic models, we can relate important decision factors reduce factor dimensionality and present the dense summary dimensions of semantic and importance. Inter and intra ballistics of the SBIFV provide important clues on how semantic packing assists in decision making. Future directions of SBIFV are to make the visualization reactive and conformal to saccades specializing targets to ballistics, such as dynamically filtering and highlighting verbal targets for left saccades and spatial targets for right saccades.

Widespread correlation patterns of fMRI signal across visual cortex reflect eccentricity organization.

PubMed

Arcaro, Michael J; Honey, Christopher J; Mruczek, Ryan E B; Kastner, Sabine; Hasson, Uri

2015-02-19

The human visual system can be divided into over two-dozen distinct areas, each of which contains a topographic map of the visual field. A fundamental question in vision neuroscience is how the visual system integrates information from the environment across different areas. Using neuroimaging, we investigated the spatial pattern of correlated BOLD signal across eight visual areas on data collected during rest conditions and during naturalistic movie viewing. The correlation pattern between areas reflected the underlying receptive field organization with higher correlations between cortical sites containing overlapping representations of visual space. In addition, the correlation pattern reflected the underlying widespread eccentricity organization of visual cortex, in which the highest correlations were observed for cortical sites with iso-eccentricity representations including regions with non-overlapping representations of visual space. This eccentricity-based correlation pattern appears to be part of an intrinsic functional architecture that supports the integration of information across functionally specialized visual areas.

Visualizing Vector Fields Using Line Integral Convolution and Dye Advection

NASA Technical Reports Server (NTRS)

Shen, Han-Wei; Johnson, Christopher R.; Ma, Kwan-Liu

1996-01-01

We present local and global techniques to visualize three-dimensional vector field data. Using the Line Integral Convolution (LIC) method to image the global vector field, our new algorithm allows the user to introduce colored 'dye' into the vector field to highlight local flow features. A fast algorithm is proposed that quickly recomputes the dyed LIC images. In addition, we introduce volume rendering methods that can map the LIC texture on any contour surface and/or translucent region defined by additional scalar quantities, and can follow the advection of colored dye throughout the volume.

Hyperspectral image visualization based on a human visual model

NASA Astrophysics Data System (ADS)

Zhang, Hongqin; Peng, Honghong; Fairchild, Mark D.; Montag, Ethan D.

2008-02-01

Hyperspectral image data can provide very fine spectral resolution with more than 200 bands, yet presents challenges for visualization techniques for displaying such rich information on a tristimulus monitor. This study developed a visualization technique by taking advantage of both the consistent natural appearance of a true color image and the feature separation of a PCA image based on a biologically inspired visual attention model. The key part is to extract the informative regions in the scene. The model takes into account human contrast sensitivity functions and generates a topographic saliency map for both images. This is accomplished using a set of linear "center-surround" operations simulating visual receptive fields as the difference between fine and coarse scales. A difference map between the saliency map of the true color image and that of the PCA image is derived and used as a mask on the true color image to select a small number of interesting locations where the PCA image has more salient features than available in the visible bands. The resulting representations preserve hue for vegetation, water, road etc., while the selected attentional locations may be analyzed by more advanced algorithms.

Gamma-Ray imaging for nuclear security and safety: Towards 3-D gamma-ray vision

NASA Astrophysics Data System (ADS)

Vetter, Kai; Barnowksi, Ross; Haefner, Andrew; Joshi, Tenzing H. Y.; Pavlovsky, Ryan; Quiter, Brian J.

2018-01-01

The development of portable gamma-ray imaging instruments in combination with the recent advances in sensor and related computer vision technologies enable unprecedented capabilities in the detection, localization, and mapping of radiological and nuclear materials in complex environments relevant for nuclear security and safety. Though multi-modal imaging has been established in medicine and biomedical imaging for some time, the potential of multi-modal data fusion for radiological localization and mapping problems in complex indoor and outdoor environments remains to be explored in detail. In contrast to the well-defined settings in medical or biological imaging associated with small field-of-view and well-constrained extension of the radiation field, in many radiological search and mapping scenarios, the radiation fields are not constrained and objects and sources are not necessarily known prior to the measurement. The ability to fuse radiological with contextual or scene data in three dimensions, in analog to radiological and functional imaging with anatomical fusion in medicine, provides new capabilities enhancing image clarity, context, quantitative estimates, and visualization of the data products. We have developed new means to register and fuse gamma-ray imaging with contextual data from portable or moving platforms. These developments enhance detection and mapping capabilities as well as provide unprecedented visualization of complex radiation fields, moving us one step closer to the realization of gamma-ray vision in three dimensions.

Visual Receptive Field Heterogeneity and Functional Connectivity of Adjacent Neurons in Primate Frontoparietal Association Cortices.

PubMed

Viswanathan, Pooja; Nieder, Andreas

2017-09-13

The basic organization principles of the primary visual cortex (V1) are commonly assumed to also hold in the association cortex such that neurons within a cortical column share functional connectivity patterns and represent the same region of the visual field. We mapped the visual receptive fields (RFs) of neurons recorded at the same electrode in the ventral intraparietal area (VIP) and the lateral prefrontal cortex (PFC) of rhesus monkeys. We report that the spatial characteristics of visual RFs between adjacent neurons differed considerably, with increasing heterogeneity from VIP to PFC. In addition to RF incongruences, we found differential functional connectivity between putative inhibitory interneurons and pyramidal cells in PFC and VIP. These findings suggest that local RF topography vanishes with hierarchical distance from visual cortical input and argue for increasingly modified functional microcircuits in noncanonical association cortices that contrast V1. SIGNIFICANCE STATEMENT Our visual field is thought to be represented faithfully by the early visual brain areas; all the information from a certain region of the visual field is conveyed to neurons situated close together within a functionally defined cortical column. We examined this principle in the association areas, PFC, and ventral intraparietal area of rhesus monkeys and found that adjacent neurons represent markedly different areas of the visual field. This is the first demonstration of such noncanonical organization of these brain areas. Copyright © 2017 the authors 0270-6474/17/378919-10$15.00/0.

Comparing different stimulus configurations for population receptive field mapping in human fMRI

PubMed Central

Alvarez, Ivan; de Haas, Benjamin; Clark, Chris A.; Rees, Geraint; Schwarzkopf, D. Samuel

2015-01-01

Population receptive field (pRF) mapping is a widely used approach to measuring aggregate human visual receptive field properties by recording non-invasive signals using functional MRI. Despite growing interest, no study to date has systematically investigated the effects of different stimulus configurations on pRF estimates from human visual cortex. Here we compared the effects of three different stimulus configurations on a model-based approach to pRF estimation: size-invariant bars and eccentricity-scaled bars defined in Cartesian coordinates and traveling along the cardinal axes, and a novel simultaneous “wedge and ring” stimulus defined in polar coordinates, systematically covering polar and eccentricity axes. We found that the presence or absence of eccentricity scaling had a significant effect on goodness of fit and pRF size estimates. Further, variability in pRF size estimates was directly influenced by stimulus configuration, particularly for higher visual areas including V5/MT+. Finally, we compared eccentricity estimation between phase-encoded and model-based pRF approaches. We observed a tendency for more peripheral eccentricity estimates using phase-encoded methods, independent of stimulus size. We conclude that both eccentricity scaling and polar rather than Cartesian stimulus configuration are important considerations for optimal experimental design in pRF mapping. While all stimulus configurations produce adequate estimates, simultaneous wedge and ring stimulation produced higher fit reliability, with a significant advantage in reduced acquisition time. PMID:25750620

Venus Quadrangle Geological Mapping: Use of Geoscience Data Visualization Systems in Mapping and Training

NASA Technical Reports Server (NTRS)

Head, James W.; Huffman, J. N.; Forsberg, A. S.; Hurwitz, D. M.; Basilevsky, A. T.; Ivanov, M. A.; Dickson, J. L.; Kumar, P. Senthil

2008-01-01

We are currently investigating new technological developments in computer visualization and analysis in order to assess their importance and utility in planetary geological analysis and mapping [1,2]. Last year we reported on the range of technologies available and on our application of these to various problems in planetary mapping [3]. In this contribution we focus on the application of these techniques and tools to Venus geological mapping at the 1:5M quadrangle scale. In our current Venus mapping projects we have utilized and tested the various platforms to understand their capabilities and assess their usefulness in defining units, establishing stratigraphic relationships, mapping structures, reaching consensus on interpretations and producing map products. We are specifically assessing how computer visualization display qualities (e.g., level of immersion, stereoscopic vs. monoscopic viewing, field of view, large vs. small display size, etc.) influence performance on scientific analysis and geological mapping. We have been exploring four different environments: 1) conventional desktops (DT), 2) semi-immersive Fishtank VR (FT) (i.e., a conventional desktop with head-tracked stereo and 6DOF input), 3) tiled wall displays (TW), and 4) fully immersive virtual reality (IVR) (e.g., "Cave Automatic Virtual Environment," or Cave system). Formal studies demonstrate that fully immersive Cave environments are superior to desktop systems for many tasks [e.g., 4].

Congruent representation of visual and acoustic space in the superior colliculus of the echolocating bat Phyllostomus discolor.

PubMed

Hoffmann, Susanne; Vega-Zuniga, Tomas; Greiter, Wolfgang; Krabichler, Quirin; Bley, Alexandra; Matthes, Mariana; Zimmer, Christiane; Firzlaff, Uwe; Luksch, Harald

2016-11-01

The midbrain superior colliculus (SC) commonly features a retinotopic representation of visual space in its superficial layers, which is congruent with maps formed by multisensory neurons and motor neurons in its deep layers. Information flow between layers is suggested to enable the SC to mediate goal-directed orienting movements. While most mammals strongly rely on vision for orienting, some species such as echolocating bats have developed alternative strategies, which raises the question how sensory maps are organized in these animals. We probed the visual system of the echolocating bat Phyllostomus discolor and found that binocular high acuity vision is frontally oriented and thus aligned with the biosonar system, whereas monocular visual fields cover a large area of peripheral space. For the first time in echolocating bats, we could show that in contrast with other mammals, visual processing is restricted to the superficial layers of the SC. The topographic representation of visual space, however, followed the general mammalian pattern. In addition, we found a clear topographic representation of sound azimuth in the deeper collicular layers, which was congruent with the superficial visual space map and with a previously documented map of orienting movements. Especially for bats navigating at high speed in densely structured environments, it is vitally important to transfer and coordinate spatial information between sensors and motor systems. Here, we demonstrate first evidence for the existence of congruent maps of sensory space in the bat SC that might serve to generate a unified representation of the environment to guide motor actions. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

A visual interface for generic message translation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blattner, M.M.; Kou, L.T.; Carlson, J.W.

1988-06-21

This paper is concerned with the translation of data structures we call messages. Messages are an example of a type of data structure encountered in generic data translation. Our objective is to provide a system that the nonprogrammer can use to specify the nature of translations from one type to another. For this reason we selected a visual interface that uses interaction techniques that do not require a knowledge of programming or command languages. The translator must accomplish two tasks: create a mapping between fields in different message types that specifies which fields have similar semantic content, and reformat ormore » translate data specifications within those fields. The translations are accomplished with appropriate, but different, visual metaphors. 14 refs., 4 figs.« less

Cassini observations of flow-like features in western Tui Regio, Titan

USGS Publications Warehouse

Barnes, J.W.; Brown, R.H.; Radebaugh, J.; Buratti, B.J.; Sotin, Christophe; Le, Mouelic S.; Rodriguez, S.; Turtle, E.P.; Perry, J.; Clark, R.; Baines, K.H.; Nicholson, P.D.

2006-01-01

A large (>3 ?? 104 km2), lobate, 5-??m-bright region seen by Cassini on Titan's leading equatorial region is best explained as a flow field. We discuss observations from the Visual and Infrared Mapping Spectrometer and Imaging Science Subsystem of the feature and present a map of the field. We establish relative ages of flow features and discuss possible formation mechanisms and the implications of this finding for the evolution of Titan's surface. Copyright 2006 by the American Geophysical Union.

Depth estimation and camera calibration of a focused plenoptic camera for visual odometry

NASA Astrophysics Data System (ADS)

Zeller, Niclas; Quint, Franz; Stilla, Uwe

2016-08-01

This paper presents new and improved methods of depth estimation and camera calibration for visual odometry with a focused plenoptic camera. For depth estimation we adapt an algorithm previously used in structure-from-motion approaches to work with images of a focused plenoptic camera. In the raw image of a plenoptic camera, scene patches are recorded in several micro-images under slightly different angles. This leads to a multi-view stereo-problem. To reduce the complexity, we divide this into multiple binocular stereo problems. For each pixel with sufficient gradient we estimate a virtual (uncalibrated) depth based on local intensity error minimization. The estimated depth is characterized by the variance of the estimate and is subsequently updated with the estimates from other micro-images. Updating is performed in a Kalman-like fashion. The result of depth estimation in a single image of the plenoptic camera is a probabilistic depth map, where each depth pixel consists of an estimated virtual depth and a corresponding variance. Since the resulting image of the plenoptic camera contains two plains: the optical image and the depth map, camera calibration is divided into two separate sub-problems. The optical path is calibrated based on a traditional calibration method. For calibrating the depth map we introduce two novel model based methods, which define the relation of the virtual depth, which has been estimated based on the light-field image, and the metric object distance. These two methods are compared to a well known curve fitting approach. Both model based methods show significant advantages compared to the curve fitting method. For visual odometry we fuse the probabilistic depth map gained from one shot of the plenoptic camera with the depth data gained by finding stereo correspondences between subsequent synthesized intensity images of the plenoptic camera. These images can be synthesized totally focused and thus finding stereo correspondences is enhanced. In contrast to monocular visual odometry approaches, due to the calibration of the individual depth maps, the scale of the scene can be observed. Furthermore, due to the light-field information better tracking capabilities compared to the monocular case can be expected. As result, the depth information gained by the plenoptic camera based visual odometry algorithm proposed in this paper has superior accuracy and reliability compared to the depth estimated from a single light-field image.

Widespread correlation patterns of fMRI signal across visual cortex reflect eccentricity organization

PubMed Central

Arcaro, Michael J; Honey, Christopher J; Mruczek, Ryan EB; Kastner, Sabine; Hasson, Uri

2015-01-01

The human visual system can be divided into over two-dozen distinct areas, each of which contains a topographic map of the visual field. A fundamental question in vision neuroscience is how the visual system integrates information from the environment across different areas. Using neuroimaging, we investigated the spatial pattern of correlated BOLD signal across eight visual areas on data collected during rest conditions and during naturalistic movie viewing. The correlation pattern between areas reflected the underlying receptive field organization with higher correlations between cortical sites containing overlapping representations of visual space. In addition, the correlation pattern reflected the underlying widespread eccentricity organization of visual cortex, in which the highest correlations were observed for cortical sites with iso-eccentricity representations including regions with non-overlapping representations of visual space. This eccentricity-based correlation pattern appears to be part of an intrinsic functional architecture that supports the integration of information across functionally specialized visual areas. DOI: http://dx.doi.org/10.7554/eLife.03952.001 PMID:25695154

UVMAS: Venus ultraviolet-visual mapping spectrometer

NASA Astrophysics Data System (ADS)

Bellucci, G.; Zasova, L.; Altieri, F.; Nuccilli, F.; Ignatiev, N.; Moroz, V.; Khatuntsev, I.; Korablev, O.; Rodin, A.

This paper summarizes the capabilities and technical solutions of an Ultraviolet Visual Mapping Spectrometer designed for remote sensing of Venus from a planetary orbiter. The UVMAS consists of a multichannel camera with a spectral range 0.19 << 0.49 μm which acquires data in several spectral channels (up to 400) with a spectral resolution of 0.58 nm. The instantaneous field of view of the instrument is 0.244 × 0.244 mrad. These characteristics allow: a) to study the upper clouds dynamics and chemistry; b) giving constraints on the unknown absorber; c) observation of the night side airglow.

Digital field mapping for stimulating Secondary School students in the recognition of geological features and landforms

NASA Astrophysics Data System (ADS)

Giardino, Marco; Magagna, Alessandra; Ferrero, Elena; Perrone, Gianluigi

2015-04-01

Digital field mapping has certainly provided geoscientists with the opportunity to map and gather data in the field directly using digital tools and software rather than using paper maps, notebooks and analogue devices and then subsequently transferring the data to a digital format for subsequent analysis. But, the same opportunity has to be recognized for Geoscience education, as well as for stimulating and helping students in the recognition of landforms and interpretation of the geological and geomorphological components of a landscape. More, an early exposure to mapping during school and prior to university can optimise the ability to "read" and identify uncertainty in 3d models. During 2014, about 200 Secondary School students (aged 12-15) of the Piedmont region (NW Italy) participated in a research program involving the use of mobile devices (smartphone and tablet) in the field. Students, divided in groups, used the application Trimble Outdoors Navigators for tracking a geological trail in the Sangone Valley and for taking georeferenced pictures and notes. Back to school, students downloaded the digital data in a .kml file for the visualization on Google Earth. This allowed them: to compare the hand tracked trail on a paper map with the digital trail, and to discuss about the functioning and the precision of the tools; to overlap a digital/semitransparent version of the 2D paper map (a Regional Technical Map) used during the field trip on the 2.5D landscape of Google Earth, as to help them in the interpretation of conventional symbols such as contour lines; to perceive the landforms seen during the field trip as a part of a more complex Pleistocene glacial landscape; to understand the classical and innovative contributions from different geoscientific disciplines to the generation of a 3D structural geological model of the Rivoli-Avigliana Morainic Amphitheatre. In 2013 and 2014, some other pilot projects have been carried out in different areas of the Piedmont region, and in the Sesia Val Grande Geopark, for testing the utility of digital field mapping in Geoscience education. Feedback from students are positive: they are stimulated and involved by the use of ICT for learning Geoscience, and they voluntary choose to work with their personal mobile device (more than 90% of them own a smartphone); they are interested in knowing the features of GPS, and of software for the visualization of satellite and aerial images, but they recognize the importance of integrating and comparing traditional and innovative methods in the field.

Designing a visualization system for hydrological data

NASA Astrophysics Data System (ADS)

Fuhrmann, Sven

2000-02-01

The field of hydrology is, as any other scientific field, strongly affected by a massive technological evolution. The spread of modern information and communication technology within the last three decades has led to an increased collection, availability and use of spatial and temporal digital hydrological data. In a two-year research period a working group in Muenster applied and developed methods for the visualization of digital hydrological data and the documentation of hydrological models. A low-cost multimedial, hydrological visualization system (HydroVIS) for the Weser river catchment was developed. The research group designed HydroVIS under freeware constraints and tried to show what kind of multimedia visualization techniques can be effectively used with a nonprofit hydrological visualization system. The system's visual components include features such as electronic maps, temporal and nontemporal cartographic animations, the display of geologic profiles, interactive diagrams and hypertext, including photographs and tables.

Torsional ARC Effectively Expands the Visual Field in Hemianopia

PubMed Central

Satgunam, PremNandhini; Peli, Eli

2012-01-01

Purpose Exotropia in congenital homonymous hemianopia has been reported to provide field expansion that is more useful when accompanied with harmonios anomalous retinal correspondence (HARC). Torsional strabismus with HARC provides a similar functional advantage. In a subject with hemianopia demonstrating a field expansion consistent with torsion we documented torsional strabismus and torsional HARC. Methods Monocular visual fields under binocular fixation conditions were plotted using a custom dichoptic visual field perimeter (DVF). The DVF was also modified to measure perceived visual directions under dissociated and associated conditions across the central 50° diameter field. The field expansion and retinal correspondence of a subject with torsional strabismus (along with exotropia and right hypertropia) with congenital homonymous hemianopia was compared to that of another exotropic subject with acquired homonymous hemianopia without torsion and to a control subject with minimal phoria. Torsional rotations of the eyes were calculated from fundus photographs and perimetry. Results Torsional ARC documented in the subject with congenital homonymous hemianopia provided a functional binocular field expansion up to 18°. Normal retinal correspondence was mapped for the full 50° visual field in the control subject and for the seeing field of the acquired homonymous hemianopia subject, limiting the functional field expansion benefit. Conclusions Torsional strabismus with ARC, when occurring with homonymous hemianopia provides useful field expansion in the lower and upper fields. Dichoptic perimetry permits documentation of ocular alignment (lateral, vertical and torsional) and perceived visual direction under binocular and monocular viewing conditions. Evaluating patients with congenital or early strabismus for HARC is useful when considering surgical correction, particularly in the presence of congenital homonymous hemianopia. PMID:22885782

Visualizing Gyrokinetic Turbulence in a Tokamak

NASA Astrophysics Data System (ADS)

Stantchev, George

2005-10-01

Multi-dimensional data output from gyrokinetic microturbulence codes are often difficult to visualize, in part due to the non-trivial geometry of the underlying grids, in part due to high irregularity of the relevant scalar field structures in turbulent regions. For instance, traditional isosurface extraction methods are likely to fail for the electrostatic potential field whose level sets may exhibit various geometric pathologies. To address these issues we develop an advanced interactive 3D gyrokinetic turbulence visualization framework which we apply in the study of microtearing instabilities calculated with GS2 in the MAST and NSTX geometries. In these simulations GS2 uses field-line-following coordinates such that the computational domain maps in physical space to a long, twisting flux tube with strong cross-sectional shear. Using statistical wavelet analysis we create a sparse multiple-scale volumetric representation of the relevant scalar fields, which we visualize via a variation of the so called splatting technique. To handle the problem of highly anisotropic flux tube configurations we adapt a geometry-driven surface illumination algorithm that places local light sources for effective feature-enhanced visualization.

Multichannel optical mapping: investigation of depth information

NASA Astrophysics Data System (ADS)

Sase, Ichiro; Eda, Hideo; Seiyama, Akitoshi; Tanabe, Hiroki C.; Takatsuki, Akira; Yanagida, Toshio

2001-06-01

Near infrared (NIR) light has become a powerful tool for non-invasive imaging of human brain activity. Many systems have been developed to capture the changes in regional brain blood flow and hemoglobin oxygenation, which occur in the human cortex in response to neural activity. We have developed a multi-channel reflectance imaging system, which can be used as a `mapping device' and also as a `multi-channel spectrophotometer'. In the present study, we visualized changes in the hemodynamics of the human occipital region in multiple ways. (1) Stimulating left and right primary visual cortex independently by showing sector shaped checkerboards sequentially over the contralateral visual field, resulted in corresponding changes in the hemodynamics observed by `mapping' measurement. (2) Simultaneous measurement of functional-MRI and NIR (changes in total hemoglobin) during visual stimulation showed good spatial and temporal correlation with each other. (3) Placing multiple channels densely over the occipital region demonstrated spatial patterns more precisely, and depth information was also acquired by placing each pair of illumination and detection fibers at various distances. These results indicate that optical method can provide data for 3D analysis of human brain functions.

Diagnostic Ability of Wide-field Retinal Nerve Fiber Layer Maps Using Swept-Source Optical Coherence Tomography for Detection of Preperimetric and Early Perimetric Glaucoma.

PubMed

Lee, Won June; Na, Kyeong Ik; Kim, Young Kook; Jeoung, Jin Wook; Park, Ki Ho

2017-06-01

To evaluate the diagnostic ability of wide-field retinal nerve fiber layer (RNFL) maps with swept-source optical coherence tomography (SS-OCT) for detection of preperimetric (PPG) and early perimetric glaucoma (EG). One hundred eighty-four eyes, including 67 healthy eyes, 43 eyes with PPG, and 74 eyes with EG, were analyzed. Patients underwent a comprehensive ocular examination including red-free RNFL photography, visual field testing and wide-field SS-OCT scanning (DRI-OCT-1 Atlantis; Topcon, Tokyo, Japan). SS-OCT provides a wide-field RNFL thickness map and a SuperPixel map, which are composed of the RNFL deviation map of the peripapillary area and the deviation map of the composition of the ganglion cell layer with the inner plexiform layer and RNFL (GC-IPL+RNFL) in the macular area. The ability to discriminate PPG and EG from healthy eyes was assessed using sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) for all parameters and criteria provided by the wide-field SS-OCT scan. The wide-field RNFL thickness map using SS-OCT showed the highest sensitivity of PPG-diagnostic and EG-diagnostic performance compared with the other SS-OCT criteria based on the internal normative base (93.0 and 97.3%, respectively). Among the SS-OCT continuous parameters, the RFNL thickness of the 7 clock-hour, inferior and inferotemporal macular ganglion cell analyses showed the largest AUC of PPG-diagnostic and EG-diagnostic performance (AUC=0.809 to 0.865). The wide-field RNFL thickness map using SS-OCT performed well in distinguishing eyes with PPG and EG from healthy eyes. In the clinical setting, wide-field RNFL maps of SS-OCT can be useful tools for detection of early-stage glaucoma.

Combined 60° Wide-Field Choroidal Thickness Maps and High-Definition En Face Vasculature Visualization Using Swept-Source Megahertz OCT at 1050 nm

PubMed Central

Mohler, Kathrin J.; Draxinger, Wolfgang; Klein, Thomas; Kolb, Jan Philip; Wieser, Wolfgang; Haritoglou, Christos; Kampik, Anselm; Fujimoto, James G.; Neubauer, Aljoscha S.; Huber, Robert; Wolf, Armin

2015-01-01

Purpose To demonstrate ultrahigh-speed swept-source optical coherence tomography (SS-OCT) at 1.68 million A-scans/s for choroidal imaging in normal and diseased eyes over a ∼60° field of view. To investigate and correlate wide-field three-dimensional (3D) choroidal thickness (ChT) and vascular patterns using ChT maps and coregistered high-definition en face images extracted from a single densely sampled Megahertz-OCT (MHz-OCT) dataset. Methods High-definition, ∼60° wide-field 3D datasets consisting of 2088 × 1024 A-scans were acquired using a 1.68 MHz prototype SS-OCT system at 1050 nm based on a Fourier-domain mode-locked laser. Nine subjects (nine eyes) with various chorioretinal diseases or without ocular pathology are presented. Coregistered ChT maps, choroidal summation maps, and depth-resolved en face images referenced to either the retinal pigment epithelium or the choroidal–scleral interface were generated using manual segmentation. Results Wide-field ChT maps showed a large inter- and intraindividual variance in peripheral and central ChT. In only four of the nine eyes, the location with the largest ChT was coincident with the fovea. The anatomy of the large lumen vessels of the outer choroid seems to play a major role in determining the global ChT pattern. Focal ChT changes with large thickness gradients were observed in some eyes. Conclusions Different ChT and vascular patterns could be visualized over ∼60° in patients for the first time using OCT. Due to focal ChT changes, a high density of thickness measurements may be favorable. High-definition depth-resolved en face images are complementary to cross sections and thickness maps and enhance the interpretation of different ChT patterns. PMID:26431482

Combined 60° Wide-Field Choroidal Thickness Maps and High-Definition En Face Vasculature Visualization Using Swept-Source Megahertz OCT at 1050 nm.

PubMed

Mohler, Kathrin J; Draxinger, Wolfgang; Klein, Thomas; Kolb, Jan Philip; Wieser, Wolfgang; Haritoglou, Christos; Kampik, Anselm; Fujimoto, James G; Neubauer, Aljoscha S; Huber, Robert; Wolf, Armin

2015-10-01

To demonstrate ultrahigh-speed swept-source optical coherence tomography (SS-OCT) at 1.68 million A-scans/s for choroidal imaging in normal and diseased eyes over a ∼60° field of view. To investigate and correlate wide-field three-dimensional (3D) choroidal thickness (ChT) and vascular patterns using ChT maps and coregistered high-definition en face images extracted from a single densely sampled Megahertz-OCT (MHz-OCT) dataset. High-definition, ∼60° wide-field 3D datasets consisting of 2088 × 1024 A-scans were acquired using a 1.68 MHz prototype SS-OCT system at 1050 nm based on a Fourier-domain mode-locked laser. Nine subjects (nine eyes) with various chorioretinal diseases or without ocular pathology are presented. Coregistered ChT maps, choroidal summation maps, and depth-resolved en face images referenced to either the retinal pigment epithelium or the choroidal-scleral interface were generated using manual segmentation. Wide-field ChT maps showed a large inter- and intraindividual variance in peripheral and central ChT. In only four of the nine eyes, the location with the largest ChT was coincident with the fovea. The anatomy of the large lumen vessels of the outer choroid seems to play a major role in determining the global ChT pattern. Focal ChT changes with large thickness gradients were observed in some eyes. Different ChT and vascular patterns could be visualized over ∼60° in patients for the first time using OCT. Due to focal ChT changes, a high density of thickness measurements may be favorable. High-definition depth-resolved en face images are complementary to cross sections and thickness maps and enhance the interpretation of different ChT patterns.

Occupancy mapping and surface reconstruction using local Gaussian processes with Kinect sensors.

PubMed

Kim, Soohwan; Kim, Jonghyuk

2013-10-01

Although RGB-D sensors have been successfully applied to visual SLAM and surface reconstruction, most of the applications aim at visualization. In this paper, we propose a noble method of building continuous occupancy maps and reconstructing surfaces in a single framework for both navigation and visualization. Particularly, we apply a Bayesian nonparametric approach, Gaussian process classification, to occupancy mapping. However, it suffers from high-computational complexity of O(n(3))+O(n(2)m), where n and m are the numbers of training and test data, respectively, limiting its use for large-scale mapping with huge training data, which is common with high-resolution RGB-D sensors. Therefore, we partition both training and test data with a coarse-to-fine clustering method and apply Gaussian processes to each local clusters. In addition, we consider Gaussian processes as implicit functions, and thus extract iso-surfaces from the scalar fields, continuous occupancy maps, using marching cubes. By doing that, we are able to build two types of map representations within a single framework of Gaussian processes. Experimental results with 2-D simulated data show that the accuracy of our approximated method is comparable to previous work, while the computational time is dramatically reduced. We also demonstrate our method with 3-D real data to show its feasibility in large-scale environments.

Resting-State Retinotopic Organization in the Absence of Retinal Input and Visual Experience

PubMed Central

Binda, Paola; Benson, Noah C.; Bridge, Holly; Watkins, Kate E.

2015-01-01

Early visual areas have neuronal receptive fields that form a sampling mosaic of visual space, resulting in a series of retinotopic maps in which the same region of space is represented in multiple visual areas. It is not clear to what extent the development and maintenance of this retinotopic organization in humans depend on retinal waves and/or visual experience. We examined the corticocortical receptive field organization of resting-state BOLD data in normally sighted, early blind, and anophthalmic (in which both eyes fail to develop) individuals and found that resting-state correlations between V1 and V2/V3 were retinotopically organized for all subject groups. These results show that the gross retinotopic pattern of resting-state connectivity across V1-V3 requires neither retinal waves nor visual experience to develop and persist into adulthood. SIGNIFICANCE STATEMENT Evidence from resting-state BOLD data suggests that the connections between early visual areas develop and are maintained even in the absence of retinal waves and visual experience. PMID:26354906

Decoding Visual Location From Neural Patterns in the Auditory Cortex of the Congenitally Deaf

PubMed Central

Almeida, Jorge; He, Dongjun; Chen, Quanjing; Mahon, Bradford Z.; Zhang, Fan; Gonçalves, Óscar F.; Fang, Fang; Bi, Yanchao

2016-01-01

Sensory cortices of individuals who are congenitally deprived of a sense can exhibit considerable plasticity and be recruited to process information from the senses that remain intact. Here, we explored whether the auditory cortex of congenitally deaf individuals represents visual field location of a stimulus—a dimension that is represented in early visual areas. We used functional MRI to measure neural activity in auditory and visual cortices of congenitally deaf and hearing humans while they observed stimuli typically used for mapping visual field preferences in visual cortex. We found that the location of a visual stimulus can be successfully decoded from the patterns of neural activity in auditory cortex of congenitally deaf but not hearing individuals. This is particularly true for locations within the horizontal plane and within peripheral vision. These data show that the representations stored within neuroplastically changed auditory cortex can align with dimensions that are typically represented in visual cortex. PMID:26423461

Brain maps, great and small: lessons from comparative studies of primate visual cortical organization

PubMed Central

Rosa, Marcello G.P; Tweedale, Rowan

2005-01-01

In this paper, we review evidence from comparative studies of primate cortical organization, highlighting recent findings and hypotheses that may help us to understand the rules governing evolutionary changes of the cortical map and the process of formation of areas during development. We argue that clear unequivocal views of cortical areas and their homologies are more likely to emerge for ‘core’ fields, including the primary sensory areas, which are specified early in development by precise molecular identification steps. In primates, the middle temporal area is probably one of these primordial cortical fields. Areas that form at progressively later stages of development correspond to progressively more recent evolutionary events, their development being less firmly anchored in molecular specification. The certainty with which areal boundaries can be delimited, and likely homologies can be assigned, becomes increasingly blurred in parallel with this evolutionary/developmental sequence. For example, while current concepts for the definition of cortical areas have been vindicated in allowing a clarification of the organization of the New World monkey ‘third tier’ visual cortex (the third and dorsomedial areas, V3 and DM), our analyses suggest that more flexible mapping criteria may be needed to unravel the organization of higher-order visual association and polysensory areas. PMID:15937007

Visualization maps for the evolution of research hotspots in the field of regional health information networks.

PubMed

Wang, Yanjun; Zheng, Jianzhong; Zhang, Ailian; Zhou, Wei; Dong, Haiyuan

2018-03-01

The aim of this study was to reveal research hotspots in the field of regional health information networks (RHINs) and use visualization techniques to explore their evolution over time and differences between countries. We conducted a literature review for a 50-year period and compared the prevalence of certain index terms during the periods 1963-1993 and 1994-2014 and in six countries. We applied keyword frequency analysis, keyword co-occurrence analysis, multidimensional scaling analysis, and network visualization technology. The total number of keywords was found to increase with time. From 1994 to 2014, the research priorities shifted from hospital planning to community health planning. The number of keywords reflecting information-based research increased. The density of the knowledge network increased significantly, and partial keywords condensed into knowledge groups. All six countries focus on keywords including Information Systems; Telemedicine; Information Service; Medical Records Systems, Computerized; Internet; etc.; however, the level of development and some research priorities are different. RHIN research has generally increased in popularity over the past 50 years. The research hotspots are evolving and are at different levels of development in different countries. Knowledge network mapping and perceptual maps provide useful information for scholars, managers, and policy-makers.

A matter of time: improvement of visual temporal processing during training-induced restoration of light detection performance

PubMed Central

Poggel, Dorothe A.; Treutwein, Bernhard; Sabel, Bernhard A.; Strasburger, Hans

2015-01-01

The issue of how basic sensory and temporal processing are related is still unresolved. We studied temporal processing, as assessed by simple visual reaction times (RT) and double-pulse resolution (DPR), in patients with partial vision loss after visual pathway lesions and investigated whether vision restoration training (VRT), a training program designed to improve light detection performance, would also affect temporal processing. Perimetric and campimetric visual field tests as well as maps of DPR thresholds and RT were acquired before and after a 3 months training period with VRT. Patient performance was compared to that of age-matched healthy subjects. Intact visual field size increased during training. Averaged across the entire visual field, DPR remained constant while RT improved slightly. However, in transition zones between the blind and intact areas (areas of residual vision) where patients had shown between 20 and 80% of stimulus detection probability in pre-training visual field tests, both DPR and RT improved markedly. The magnitude of improvement depended on the defect depth (or degree of intactness) of the respective region at baseline. Inter-individual training outcome variability was very high, with some patients showing little change and others showing performance approaching that of healthy controls. Training-induced improvement of light detection in patients with visual field loss thus generalized to dynamic visual functions. The findings suggest that similar neural mechanisms may underlie the impairment and subsequent training-induced functional recovery of both light detection and temporal processing. PMID:25717307

The Theory-based Influence of Map Features on Risk Beliefs: Self-reports of What is Seen and Understood for Maps Depicting an Environmental Health Hazard

PubMed Central

Vatovec, Christine

2013-01-01

Theory-based research is needed to understand how maps of environmental health risk information influence risk beliefs and protective behavior. Using theoretical concepts from multiple fields of study including visual cognition, semiotics, health behavior, and learning and memory supports a comprehensive assessment of this influence. We report results from thirteen cognitive interviews that provide theory-based insights into how visual features influenced what participants saw and the meaning of what they saw as they viewed three formats of water test results for private wells (choropleth map, dot map, and a table). The unit of perception, color, proximity to hazards, geographic distribution, and visual salience had substantial influences on what participants saw and their resulting risk beliefs. These influences are explained by theoretical factors that shape what is seen, properties of features that shape cognition (pre-attentive, symbolic, visual salience), information processing (top-down and bottom-up), and the strength of concrete compared to abstract information. Personal relevance guided top-down attention to proximal and larger hazards that shaped stronger risk beliefs. Meaning was more local for small perceptual units and global for large units. Three aspects of color were important: pre-attentive “incremental risk” meaning of sequential shading, symbolic safety meaning of stoplight colors, and visual salience that drew attention. The lack of imagery, geographic information, and color diminished interest in table information. Numeracy and prior beliefs influenced comprehension for some participants. Results guided the creation of an integrated conceptual framework for application to future studies. Ethics should guide the selection of map features that support appropriate communication goals. PMID:22715919

The theory-based influence of map features on risk beliefs: self-reports of what is seen and understood for maps depicting an environmental health hazard.

PubMed

Severtson, Dolores J; Vatovec, Christine

2012-08-01

Theory-based research is needed to understand how maps of environmental health risk information influence risk beliefs and protective behavior. Using theoretical concepts from multiple fields of study including visual cognition, semiotics, health behavior, and learning and memory supports a comprehensive assessment of this influence. The authors report results from 13 cognitive interviews that provide theory-based insights into how visual features influenced what participants saw and the meaning of what they saw as they viewed 3 formats of water test results for private wells (choropleth map, dot map, and a table). The unit of perception, color, proximity to hazards, geographic distribution, and visual salience had substantial influences on what participants saw and their resulting risk beliefs. These influences are explained by theoretical factors that shape what is seen, properties of features that shape cognition (preattentive, symbolic, visual salience), information processing (top-down and bottom-up), and the strength of concrete compared with abstract information. Personal relevance guided top-down attention to proximal and larger hazards that shaped stronger risk beliefs. Meaning was more local for small perceptual units and global for large units. Three aspects of color were important: preattentive "incremental risk" meaning of sequential shading, symbolic safety meaning of stoplight colors, and visual salience that drew attention. The lack of imagery, geographic information, and color diminished interest in table information. Numeracy and prior beliefs influenced comprehension for some participants. Results guided the creation of an integrated conceptual framework for application to future studies. Ethics should guide the selection of map features that support appropriate communication goals.

Surface mapping of spike potential fields: experienced EEGers vs. computerized analysis.

PubMed

Koszer, S; Moshé, S L; Legatt, A D; Shinnar, S; Goldensohn, E S

1996-03-01

An EEG epileptiform spike focus recorded with scalp electrodes is clinically localized by visual estimation of the point of maximal voltage and the distribution of its surrounding voltages. We compared such estimated voltage maps, drawn by experienced electroencephalographers (EEGers), with a computerized spline interpolation technique employed in the commercially available software package FOCUS. Twenty-two spikes were recorded from 15 patients during long-term continuous EEG monitoring. Maps of voltage distribution from the 28 electrodes surrounding the points of maximum change in slope (the spike maximum) were constructed by the EEGer. The same points of maximum spike and voltage distributions at the 29 electrodes were mapped by computerized spline interpolation and a comparison between the two methods was made. The findings indicate that the computerized spline mapping techniques employed in FOCUS construct voltage maps with similar maxima and distributions as the maps created by experienced EEGers. The dynamics of spike activity, including correlations, are better visualized using the computerized technique than by manual interpretation alone. Its use as a technique for spike localization is accurate and adds information of potential clinical value.

Parasol cell mosaics are unlikely to drive the formation of structured orientation maps in primary visual cortex.

PubMed

Hore, Victoria R A; Troy, John B; Eglen, Stephen J

2012-11-01

The receptive fields of on- and off-center parasol cell mosaics independently tile the retina to ensure efficient sampling of visual space. A recent theoretical model represented the on- and off-center mosaics by noisy hexagonal lattices of slightly different density. When the two lattices are overlaid, long-range Moiré interference patterns are generated. These Moiré interference patterns have been suggested to drive the formation of highly structured orientation maps in visual cortex. Here, we show that noisy hexagonal lattices do not capture the spatial statistics of parasol cell mosaics. An alternative model based upon local exclusion zones, termed as the pairwise interaction point process (PIPP) model, generates patterns that are statistically indistinguishable from parasol cell mosaics. A key difference between the PIPP model and the hexagonal lattice model is that the PIPP model does not generate Moiré interference patterns, and hence stimulated orientation maps do not show any hexagonal structure. Finally, we estimate the spatial extent of spatial correlations in parasol cell mosaics to be only 200-350 μm, far less than that required to generate Moiré interference. We conclude that parasol cell mosaics are too disordered to drive the formation of highly structured orientation maps in visual cortex.

Visualizing Soil Landscapes on Mobile Devices

NASA Astrophysics Data System (ADS)

Schulze, Darrell; Lindbo, David

2016-04-01

The Integrating Spatial Educational Experiences (Isee) project utilizes the most detailed US soil survey data to create thematic maps of soil properties that are then combined with a highly optimized hillshade basemap for display. The Isee app, currently available for the iPad platform from the Apple App Store, allows the cached maps to be zoomed and panned quickly to any location down to a scale of 1:18,000. Maps currently available for the states of Indiana, Illinois, Kentucky, Ohio, Texas, West Virginia, and Wisconsin include, Dominant Soil Parent Materials, Natural Soil Drainage Classes, Limiting Layers, Surface Soil Colors, and Acid Subsoils. Other thematic maps will be added in the future. The ability to zoom, pan, and change maps quickly allows the user to see and understand soil landscape relationships that are not often apparent using static maps, while the ability to access the maps conveniently in the field allows the user to see how soil landscape features on the maps appear in the field.

Implementation of visual data mining for unsteady blood flow field in an aortic aneurysm.

PubMed

Morizawa, Seiichiro; Shimoyama, Koji; Obayashi, Shigeru; Funamoto, Kenichi; Hayase, Toshiyuki

2011-12-01

This study was performed to determine the relations between the features of wall shear stress and aneurysm rupture. For this purpose, visual data mining was performed in unsteady blood flow simulation data for an aortic aneurysm. The time-series data of wall shear stress given at each grid point were converted to spatial and temporal indices, and the grid points were sorted using a self-organizing map based on the similarity of these indices. Next, the results of cluster analysis were mapped onto the real space of the aortic aneurysm to specify the regions that may lead to aneurysm rupture. With reference to previous reports regarding aneurysm rupture, the visual data mining suggested specific hemodynamic features that cause aneurysm rupture. GRAPHICAL ABSTRACT:

Is the Cortical Deficit in Amblyopia Due to Reduced Cortical Magnification, Loss of Neural Resolution, or Neural Disorganization?

PubMed

Clavagnier, Simon; Dumoulin, Serge O; Hess, Robert F

2015-11-04

The neural basis of amblyopia is a matter of debate. The following possibilities have been suggested: loss of foveal cells, reduced cortical magnification, loss of spatial resolution of foveal cells, and topographical disarray in the cellular map. To resolve this we undertook a population receptive field (pRF) functional magnetic resonance imaging analysis in the central field in humans with moderate-to-severe amblyopia. We measured the relationship between averaged pRF size and retinal eccentricity in retinotopic visual areas. Results showed that cortical magnification is normal in the foveal field of strabismic amblyopes. However, the pRF sizes are enlarged for the amblyopic eye. We speculate that the pRF enlargement reflects loss of cellular resolution or an increased cellular positional disarray within the representation of the amblyopic eye. The neural basis of amblyopia, a visual deficit affecting 3% of the human population, remains a matter of debate. We undertook the first population receptive field functional magnetic resonance imaging analysis in participants with amblyopia and compared the projections from the amblyopic and fellow normal eye in the visual cortex. The projection from the amblyopic eye was found to have a normal cortical magnification factor, enlarged population receptive field sizes, and topographic disorganization in all early visual areas. This is consistent with an explanation of amblyopia as an immature system with a normal complement of cells whose spatial resolution is reduced and whose topographical map is disordered. This bears upon a number of competing theories for the psychophysical defect and affects future treatment therapies. Copyright © 2015 the authors 0270-6474/15/3514740-16$15.00/0.

Being First Matters: Topographical Representational Similarity Analysis of ERP Signals Reveals Separate Networks for Audiovisual Temporal Binding Depending on the Leading Sense.

PubMed

Cecere, Roberto; Gross, Joachim; Willis, Ashleigh; Thut, Gregor

2017-05-24

In multisensory integration, processing in one sensory modality is enhanced by complementary information from other modalities. Intersensory timing is crucial in this process because only inputs reaching the brain within a restricted temporal window are perceptually bound. Previous research in the audiovisual field has investigated various features of the temporal binding window, revealing asymmetries in its size and plasticity depending on the leading input: auditory-visual (AV) or visual-auditory (VA). Here, we tested whether separate neuronal mechanisms underlie this AV-VA dichotomy in humans. We recorded high-density EEG while participants performed an audiovisual simultaneity judgment task including various AV-VA asynchronies and unisensory control conditions (visual-only, auditory-only) and tested whether AV and VA processing generate different patterns of brain activity. After isolating the multisensory components of AV-VA event-related potentials (ERPs) from the sum of their unisensory constituents, we ran a time-resolved topographical representational similarity analysis (tRSA) comparing the AV and VA ERP maps. Spatial cross-correlation matrices were built from real data to index the similarity between the AV and VA maps at each time point (500 ms window after stimulus) and then correlated with two alternative similarity model matrices: AV maps = VA maps versus AV maps ≠ VA maps The tRSA results favored the AV maps ≠ VA maps model across all time points, suggesting that audiovisual temporal binding (indexed by synchrony perception) engages different neural pathways depending on the leading sense. The existence of such dual route supports recent theoretical accounts proposing that multiple binding mechanisms are implemented in the brain to accommodate different information parsing strategies in auditory and visual sensory systems. SIGNIFICANCE STATEMENT Intersensory timing is a crucial aspect of multisensory integration, determining whether and how inputs in one modality enhance stimulus processing in another modality. Our research demonstrates that evaluating synchrony of auditory-leading (AV) versus visual-leading (VA) audiovisual stimulus pairs is characterized by two distinct patterns of brain activity. This suggests that audiovisual integration is not a unitary process and that different binding mechanisms are recruited in the brain based on the leading sense. These mechanisms may be relevant for supporting different classes of multisensory operations, for example, auditory enhancement of visual attention (AV) and visual enhancement of auditory speech (VA). Copyright © 2017 Cecere et al.

New approach to estimating variability in visual field data using an image processing technique.

PubMed Central

Crabb, D P; Edgar, D F; Fitzke, F W; McNaught, A I; Wynn, H P

1995-01-01

AIMS--A new framework for evaluating pointwise sensitivity variation in computerised visual field data is demonstrated. METHODS--A measure of local spatial variability (LSV) is generated using an image processing technique. Fifty five eyes from a sample of normal and glaucomatous subjects, examined on the Humphrey field analyser (HFA), were used to illustrate the method. RESULTS--Significant correlation between LSV and conventional estimates--namely, HFA pattern standard deviation and short term fluctuation, were found. CONCLUSION--LSV is not dependent on normals' reference data or repeated threshold determinations, thus potentially reducing test time. Also, the illustrated pointwise maps of LSV could provide a method for identifying areas of fluctuation commonly found in early glaucomatous field loss. PMID:7703196

Integration of spectral domain optical coherence tomography with microperimetry generates unique datasets for the simultaneous identification of visual function and retinal structure in ophthalmological applications

NASA Astrophysics Data System (ADS)

Koulen, Peter; Gallimore, Gary; Vincent, Ryan D.; Sabates, Nelson R.; Sabates, Felix N.

2011-06-01

Conventional perimeters are used routinely in various eye disease states to evaluate the central visual field and to quantitatively map sensitivity. However, standard automated perimetry proves difficult for retina and specifically macular disease due to the need for central and steady fixation. Advances in instrumentation have led to microperimetry, which incorporates eye tracking for placement of macular sensitivity values onto an image of the macular fundus thus enabling a precise functional and anatomical mapping of the central visual field. Functional sensitivity of the retina can be compared with the observed structural parameters that are acquired with high-resolution spectral domain optical coherence tomography and by integration of scanning laser ophthalmoscope-driven imaging. Findings of the present study generate a basis for age-matched comparison of sensitivity values in patients with macular pathology. Microperimetry registered with detailed structural data performed before and after intervention treatments provides valuable information about macular function, disease progression and treatment success. This approach also allows for the detection of disease or treatment related changes in retinal sensitivity when visual acuity is not affected and can drive the decision making process in choosing different treatment regimens and guiding visual rehabilitation. This has immediate relevance for applications in central retinal vein occlusion, central serous choroidopathy, age-related macular degeneration, familial macular dystrophy and several other forms of retina related visual disability.

Digital Geologic Mapping and Integration with the Geoweb: The Death Knell for Exclusively Paper Geologic Maps

NASA Astrophysics Data System (ADS)

House, P. K.

2008-12-01

The combination of traditional methods of geologic mapping with rapidly developing web-based geospatial applications ('the geoweb') and the various collaborative opportunities of web 2.0 have the potential to change the nature, value, and relevance of geologic maps and related field studies. Parallel advances in basic GPS technology, digital photography, and related integrative applications provide practicing geologic mappers with greatly enhanced methods for collecting, visualizing, interpreting, and disseminating geologic information. Even a cursory application of available tools can make field and office work more enriching and efficient; whereas more advanced and systematic applications provide new avenues for collaboration, outreach, and public education. Moreover, they ensure a much broader audience among an immense number of internet savvy end-users with very specific expectations for geospatial data availability. Perplexingly, the geologic community as a whole is not fully exploring this opportunity despite the inevitable revolution in portends. The slow acceptance follows a broad generational trend wherein seasoned professionals are lagging behind geology students and recent graduates in their grasp of and interest in the capabilities of the geoweb and web 2.0 types of applications. Possible explanations for this include: fear of the unknown, fear of learning curve, lack of interest, lack of academic/professional incentive, and (hopefully not) reluctance toward open collaboration. Although some aspects of the expanding geoweb are cloaked in arcane computer code, others are extremely simple to understand and use. A particularly obvious and simple application to enhance any field study is photo geotagging, the digital documentation of the locations of key outcrops, illustrative vistas, and particularly complicated geologic field relations. Viewing geotagged photos in their appropriate context on a virtual globe with high-resolution imagery can be an extremely useful accompaniment to compilation of field mapping efforts. It can also complement published geologic maps by vastly improving their comprehensibility when field photos, and specific notes can be viewed interactively with them. Other useful applications include GPS tracking/documentation of field traverses; invoking multiple geologic layers; 3-D visualizations of terrain and structure; and online collaboration with colleagues via blogs or wikis. Additional steps towards collaborative geologic mapping on the web may also enhance efficient and open sharing of data and ideas. Geologists are well aware that paper geologic maps can convey tremendous amounts of information. Digital geologic maps linked via a virtual globe with field data, diverse imagery, historical photographs, explanatory diagrams, and 3-D models convey a much greater amount of information and can provide a much richer context for comprehension and interpretation. They can also serve as an efficient, entertaining, and potentially compelling mechanism for fostering inspiration in the minds of budding (and aging) geologists.

Wide-Field Raman Imaging of Dental Lesions

PubMed Central

Yang, Shan; Li, Bolan; Akkus, Anna; Akkus, Ozan; Lang, Lisa

2014-01-01

Detection of dental caries at the onset remains as a great challenge in dentistry. Raman spectroscopy could be successfully applied towards detecting caries since it is sensitive to the amount of the Raman active mineral crystals, the most abundant component of enamel. Effective diagnosis requires full examination of a tooth surface via a Raman mapping. Point-scan Raman mapping is not clinically relevant (feasible) due to lengthy data acquisition time. In this work, a wide-field Raman imaging system was assembled based on a high-sensitivity 2D CCD camera for imaging the mineralization status of teeth with lesions. Wide-field images indicated some lesions to be hypomineralized and others to be hypermineralized. The observations of wide-field Raman imaging were in agreement with point-scan Raman mapping. Therefore, sound enamel and lesions can be discriminated by Raman imaging of the mineral content. In conclusion, wide-field Raman imaging is a potentially useful tool for visualization of dental lesions in the clinic. PMID:24781363

Nerve Fiber Flux Analysis Using Wide-Field Swept-Source Optical Coherence Tomography.

PubMed

Tan, Ou; Liu, Liang; Liu, Li; Huang, David

2018-02-01

To devise a method to quantify nerve fibers over their arcuate courses over an extended peripapillary area using optical coherence tomography (OCT). Participants were imaged with 8 × 8-mm volumetric OCT scans centered at the optic disc. A new quantity, nerve fiber flux (NFF), represents the cross-sectional area transected perpendicular to the nerve fibers. The peripapillary area was divided into 64 tracks with equal flux. An iterative algorithm traced the trajectory of the tracks assuming that the relative distribution of the NFF was conserved with compensation for fiber connections to ganglion cells on the macular side. Average trajectory was averaged from normal eyes and use to calculate the NFF maps for glaucomatous eyes. The NFF maps were divided into eight sectors that correspond to visual field regions. There were 24 healthy and 10 glaucomatous eyes enrolled. The algorithm converged on similar patterns of NFL tracks for all healthy eyes. In glaucomatous eyes, NFF correlated with visual field sensitivity in the arcuate sectors (Spearman ρ = 0.53-0.62). Focal nerve fiber loss in glaucomatous eyes appeared as uniform tracks of NFF defects that followed the expected arcuate fiber trajectory. Using an algorithm based on the conservation of flux, we derived nerve fiber trajectories in the peripapillary area. The NFF map is useful for the visualization of focal defects and quantification of sector nerve fiber loss from wide-area volumetric OCT scans. NFF provides a cumulative measure of volumetric loss along nerve fiber tracks and could improve the detection of focal glaucoma damage.

Hydrothermal Diamond Anvil Cell (HDAC): From Visual Observation to X-ray Absorption Spectroscopy

NASA Astrophysics Data System (ADS)

Bassett, W. A.; Mibe, K.

2006-05-01

A fluid sample contained in a Re gasket between two diamond anvils can be subjected to pressures up to 2.5 GPa and temperatures up to 1200°C in a resistively heated hydrothermal diamond anvil cell (HDAC). Thermocouples are used to measure temperature. The constant-volume sample chamber permits isochoric measurements that can be used to determine pressure from the equation of state of H2O and to map phases and properties in P-T space. A movie of reactions between K-feldspar and water up to 2.5 GPa and 880°C illustrates the use of visual observations for mapping coexisting solution, melt, and solid phases. X-ray absorption spectroscopy of ZnBr2 in solution up to 500°C and 500 MPa shows hydrogen bond breaking in the hydration shells of the ZnBr42- and Br- ions with increasing temperature. In other studies the stability field of ikaite (CaCO3·6H2O) has been mapped by visual observation and Raman spectroscopy; the phases of montmorillonite have been mapped by X-ray diffraction; and the leaching of Pb from zircon has been measured by X-ray microprobe.

Nonretinotopic visual processing in the brain.

PubMed

Melcher, David; Morrone, Maria Concetta

2015-01-01

A basic principle in visual neuroscience is the retinotopic organization of neural receptive fields. Here, we review behavioral, neurophysiological, and neuroimaging evidence for nonretinotopic processing of visual stimuli. A number of behavioral studies have shown perception depending on object or external-space coordinate systems, in addition to retinal coordinates. Both single-cell neurophysiology and neuroimaging have provided evidence for the modulation of neural firing by gaze position and processing of visual information based on craniotopic or spatiotopic coordinates. Transient remapping of the spatial and temporal properties of neurons contingent on saccadic eye movements has been demonstrated in visual cortex, as well as frontal and parietal areas involved in saliency/priority maps, and is a good candidate to mediate some of the spatial invariance demonstrated by perception. Recent studies suggest that spatiotopic selectivity depends on a low spatial resolution system of maps that operates over a longer time frame than retinotopic processing and is strongly modulated by high-level cognitive factors such as attention. The interaction of an initial and rapid retinotopic processing stage, tied to new fixations, and a longer lasting but less precise nonretinotopic level of visual representation could underlie the perception of both a detailed and a stable visual world across saccadic eye movements.

The Trial Software version for DEMETER power spectrum files visualization and mapping

NASA Astrophysics Data System (ADS)

Lozbin, Anatoliy; Inchin, Alexander; Shpadi, Maxim

2010-05-01

In the frame of Kazakhstan's Scientific Space System creation for earthquakes precursors research, the hardware and software of DEMETER satellite was investigated. The data processing Software of DEMETER is based on package SWAN under IDL Virtual machine and realizes many features, but we can't find an important tool for the spectrograms analysis - space-time visualization of power spectrum files from electromagnetic devices as ICE and IMSC. For elimination of this problem we have developed Software which is offered to use. The DeSS (DEMETER Spectrogram Software) - it is Software for visualization, analysis and a mapping of power spectrum data from electromagnetic devices ICE and IMSC. The Software primary goal is to give the researcher friendly tool for the analysis of electromagnetic data from DEMETER Satellite for earthquake precursors and other ionosphere events researches. The Input data for DeSS Software is a power spectrum files: - Power spectrum of 1 component of the electric field in the VLF range (APID 1132); - Power spectrum of 1 component of the electric field in the HF range (APID 1134); - Power spectrum of 1 component of the magnetic field in the VLF range (APID 1137). The main features and operations of the software is possible: - various time and frequency filtration; - visualization of time dependence of signal intensity on fixed frequency; - spectral density visualization for fixed frequency range; - spectrogram autosize and smooth spectrogram; - the information in each point of the spectrogram: time, frequency and intensity; - the spectrum information in the separate window, consisting of 4 blocks; - data mapping with 6 range scale. On the map we can browse next information: - satellite orbit; - conjugate point at the satellite altitude; - north conjugate point at the altitude 110 km; - south conjugate point at the altitude 110 km. This is only trial software version to help the researchers and we always ready collaborate with scientists for software improvement. References: 1. D.Lagoutte, J.Y. Brochot, D. de Carvalho, L.Madrias and M. Parrot. DEMETER Microsatellite. Scientific Mission Center. Data product description. DMT-SP-9-CM-6054-LPC. 2. D.Lagoutte, J.Y. Brochot, P.Latremoliere. SWAN - Software for Waveform Analysis. LPCE/NI/003.E - Part 1 (User's guide), Part 2 (Analysis tools), Part 3 (User's project interface).

A linear model fails to predict orientation selectivity of cells in the cat visual cortex.

PubMed Central

Volgushev, M; Vidyasagar, T R; Pei, X

1996-01-01

1. Postsynaptic potentials (PSPs) evoked by visual stimulation in simple cells in the cat visual cortex were recorded using in vivo whole-cell technique. Responses to small spots of light presented at different positions over the receptive field and responses to elongated bars of different orientations centred on the receptive field were recorded. 2. To test whether a linear model can account for orientation selectivity of cortical neurones, responses to elongated bars were compared with responses predicted by a linear model from the receptive field map obtained from flashing spots. 3. The linear model faithfully predicted the preferred orientation, but not the degree of orientation selectivity or the sharpness of orientation tuning. The ratio of optimal to non-optimal responses was always underestimated by the model. 4. Thus non-linear mechanisms, which can include suppression of non-optimal responses and/or amplification of optimal responses, are involved in the generation of orientation selectivity in the primary visual cortex. PMID:8930828

Image Processor

NASA Technical Reports Server (NTRS)

1989-01-01

Texas Instruments Programmable Remapper is a research tool used to determine how to best utilize the part of a patient's visual field still usable by mapping onto his field of vision with manipulated imagery. It is an offshoot of a NASA program for speeding up, improving the accuracy of pattern recognition in video imagery. The Remapper enables an image to be "pushed around" so more of it falls into the functional portions in the retina of a low vision person. It works at video rates, and researchers hope to significantly reduce its size and cost, creating a wearable prosthesis for visually impaired people.

Overcoming the momentum of anachronism: American geologic mapping in a twenty-first-century world

USGS Publications Warehouse

House, P. Kyle; Clark, Ryan; Kopera, Joe

2013-01-01

The practice of geologic mapping is undergoing conceptual and methodological transformation. Profound changes in digital technology in the past 10 yr have potential to impact all aspects of geologic mapping. The future of geologic mapping as a relevant scientific enterprise depends on widespread adoption of new technology and ideas about the collection, meaning, and utility of geologic map data. It is critical that the geologic community redefine the primary elements of the traditional paper geologic map and improve the integration of the practice of making maps in the field and office with the new ways to record, manage, share, and visualize their underlying data. A modern digital geologic mapping model will enhance scientific discovery, meet elevated expectations of modern geologic map users, and accommodate inevitable future changes in technology.

Fundamentals of Structural Geology

NASA Astrophysics Data System (ADS)

Pollard, David D.; Fletcher, Raymond C.

2005-09-01

Fundamentals of Structural Geology provides a new framework for the investigation of geological structures by integrating field mapping and mechanical analysis. Assuming a basic knowledge of physical geology, introductory calculus and physics, it emphasizes the observational data, modern mapping technology, principles of continuum mechanics, and the mathematical and computational skills, necessary to quantitatively map, describe, model, and explain deformation in Earth's lithosphere. By starting from the fundamental conservation laws of mass and momentum, the constitutive laws of material behavior, and the kinematic relationships for strain and rate of deformation, the authors demonstrate the relevance of solid and fluid mechanics to structural geology. This book offers a modern quantitative approach to structural geology for advanced students and researchers in structural geology and tectonics. It is supported by a website hosting images from the book, additional colour images, student exercises and MATLAB scripts. Solutions to the exercises are available to instructors. The book integrates field mapping using modern technology with the analysis of structures based on a complete mechanics MATLAB is used to visualize physical fields and analytical results and MATLAB scripts can be downloaded from the website to recreate textbook graphics and enable students to explore their choice of parameters and boundary conditions The supplementary website hosts color images of outcrop photographs used in the text, supplementary color images, and images of textbook figures for classroom presentations The textbook website also includes student exercises designed to instill the fundamental relationships, and to encourage the visualization of the evolution of geological structures; solutions are available to instructors

Early Monocular Defocus Disrupts the Normal Development of Receptive-Field Structure in V2 Neurons of Macaque Monkeys

PubMed Central

Tao, Xiaofeng; Zhang, Bin; Shen, Guofu; Wensveen, Janice; Smith, Earl L.; Nishimoto, Shinji; Ohzawa, Izumi

2014-01-01

Experiencing different quality images in the two eyes soon after birth can cause amblyopia, a developmental vision disorder. Amblyopic humans show the reduced capacity for judging the relative position of a visual target in reference to nearby stimulus elements (position uncertainty) and often experience visual image distortion. Although abnormal pooling of local stimulus information by neurons beyond striate cortex (V1) is often suggested as a neural basis of these deficits, extrastriate neurons in the amblyopic brain have rarely been studied using microelectrode recording methods. The receptive field (RF) of neurons in visual area V2 in normal monkeys is made up of multiple subfields that are thought to reflect V1 inputs and are capable of encoding the spatial relationship between local stimulus features. We created primate models of anisometropic amblyopia and analyzed the RF subfield maps for multiple nearby V2 neurons of anesthetized monkeys by using dynamic two-dimensional noise stimuli and reverse correlation methods. Unlike in normal monkeys, the subfield maps of V2 neurons in amblyopic monkeys were severely disorganized: subfield maps showed higher heterogeneity within each neuron as well as across nearby neurons. Amblyopic V2 neurons exhibited robust binocular suppression and the strength of the suppression was positively correlated with the degree of hereogeneity and the severity of amblyopia in individual monkeys. Our results suggest that the disorganized subfield maps and robust binocular suppression of amblyopic V2 neurons are likely to adversely affect the higher stages of cortical processing resulting in position uncertainty and image distortion. PMID:25297110

Individual analysis of inter and intragrain defects in electrically characterized polycrystalline silicon nanowire TFTs by multicomponent dark-field imaging based on nanobeam electron diffraction two-dimensional mapping

NASA Astrophysics Data System (ADS)

Asano, Takanori; Takaishi, Riichiro; Oda, Minoru; Sakuma, Kiwamu; Saitoh, Masumi; Tanaka, Hiroki

2018-04-01

We visualize the grain structures for individual nanosized thin film transistors (TFTs), which are electrically characterized, with an improved data processing technique for the dark-field image reconstruction of nanobeam electron diffraction maps. Our individual crystal analysis gives the one-to-one correspondence of TFTs with different grain boundary structures, such as random and coherent boundaries, to the characteristic degradations of ON-current and threshold voltage. Furthermore, the local crystalline uniformity inside a single grain is detected as the difference in diffraction intensity distribution.

Localized direction selective responses in the dendrites of visual interneurons of the fly

PubMed Central

2010-01-01

Background The various tasks of visual systems, including course control, collision avoidance and the detection of small objects, require at the neuronal level the dendritic integration and subsequent processing of many spatially distributed visual motion inputs. While much is known about the pooled output in these systems, as in the medial superior temporal cortex of monkeys or in the lobula plate of the insect visual system, the motion tuning of the elements that provide the input has yet received little attention. In order to visualize the motion tuning of these inputs we examined the dendritic activation patterns of neurons that are selective for the characteristic patterns of wide-field motion, the lobula-plate tangential cells (LPTCs) of the blowfly. These neurons are known to sample direction-selective motion information from large parts of the visual field and combine these signals into axonal and dendro-dendritic outputs. Results Fluorescence imaging of intracellular calcium concentration allowed us to take a direct look at the local dendritic activity and the resulting local preferred directions in LPTC dendrites during activation by wide-field motion in different directions. These 'calcium response fields' resembled a retinotopic dendritic map of local preferred directions in the receptive field, the layout of which is a distinguishing feature of different LPTCs. Conclusions Our study reveals how neurons acquire selectivity for distinct visual motion patterns by dendritic integration of the local inputs with different preferred directions. With their spatial layout of directional responses, the dendrites of the LPTCs we investigated thus served as matched filters for wide-field motion patterns. PMID:20384983

Limits on perceptual encoding can be predicted from known receptive field properties of human visual cortex.

PubMed

Cohen, Michael A; Rhee, Juliana Y; Alvarez, George A

2016-01-01

Human cognition has a limited capacity that is often attributed to the brain having finite cognitive resources, but the nature of these resources is usually not specified. Here, we show evidence that perceptual interference between items can be predicted by known receptive field properties of the visual cortex, suggesting that competition within representational maps is an important source of the capacity limitations of visual processing. Across the visual hierarchy, receptive fields get larger and represent more complex, high-level features. Thus, when presented simultaneously, high-level items (e.g., faces) will often land within the same receptive fields, while low-level items (e.g., color patches) will often not. Using a perceptual task, we found long-range interference between high-level items, but only short-range interference for low-level items, with both types of interference being weaker across hemifields. Finally, we show that long-range interference between items appears to occur primarily during perceptual encoding and not during working memory maintenance. These results are naturally explained by the distribution of receptive fields and establish a link between perceptual capacity limits and the underlying neural architecture. (c) 2015 APA, all rights reserved).

Preliminary atlas of active shallow tectonic deformation in the Puget Lowland, Washington

USGS Publications Warehouse

Barnett, Elizabeth A.; Haugerud, Ralph A.; Sherrod, Brian L.; Weaver, Craig S.; Pratt, Thomas L.; Blakely, Richard J.

2010-01-01

This atlas presents an up-to-date map compilation of the geological and geophysical observations that underpin interpretations of active, surface-deforming faults in the Puget Lowland, Washington. Shallow lowland faults are mapped where observations of deformation from paleoseismic, seismic-reflection, and potential-field investigations converge. Together, results from these studies strengthen the identification and characterization of regional faults and show that as many as a dozen shallow faults have been active during the Holocene. The suite of maps presented in our atlas identifies sites that have evidence of deformation attributed to these shallow faults. For example, the paleoseismic-investigations map shows where coseismic surface rupture and deformation produced geomorphic scarps and deformed shorelines. Other maps compile results of seismic-reflection and potential-field studies that demonstrate evidence of deformation along suspected fault structures in the subsurface. Summary maps show the fault traces derived from, and draped over, the datasets presented in the preceding maps. Overall, the atlas provides map users with a visual overview of the observations and interpretations that support the existence of active, shallow faults beneath the densely populated Puget Lowland.

Auditory and visual interactions between the superior and inferior colliculi in the ferret.

PubMed

Stitt, Iain; Galindo-Leon, Edgar; Pieper, Florian; Hollensteiner, Karl J; Engler, Gerhard; Engel, Andreas K

2015-05-01

The integration of visual and auditory spatial information is important for building an accurate perception of the external world, but the fundamental mechanisms governing such audiovisual interaction have only partially been resolved. The earliest interface between auditory and visual processing pathways is in the midbrain, where the superior (SC) and inferior colliculi (IC) are reciprocally connected in an audiovisual loop. Here, we investigate the mechanisms of audiovisual interaction in the midbrain by recording neural signals from the SC and IC simultaneously in anesthetized ferrets. Visual stimuli reliably produced band-limited phase locking of IC local field potentials (LFPs) in two distinct frequency bands: 6-10 and 15-30 Hz. These visual LFP responses co-localized with robust auditory responses that were characteristic of the IC. Imaginary coherence analysis confirmed that visual responses in the IC were not volume-conducted signals from the neighboring SC. Visual responses in the IC occurred later than retinally driven superficial SC layers and earlier than deep SC layers that receive indirect visual inputs, suggesting that retinal inputs do not drive visually evoked responses in the IC. In addition, SC and IC recording sites with overlapping visual spatial receptive fields displayed stronger functional connectivity than sites with separate receptive fields, indicating that visual spatial maps are aligned across both midbrain structures. Reciprocal coupling between the IC and SC therefore probably serves the dynamic integration of visual and auditory representations of space. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Mapping and characterization of positive and negative BOLD responses to visual stimulation in multiple brain regions at 7T.

PubMed

Jorge, João; Figueiredo, Patrícia; Gruetter, Rolf; van der Zwaag, Wietske

2018-06-01

External stimuli and tasks often elicit negative BOLD responses in various brain regions, and growing experimental evidence supports that these phenomena are functionally meaningful. In this work, the high sensitivity available at 7T was explored to map and characterize both positive (PBRs) and negative BOLD responses (NBRs) to visual checkerboard stimulation, occurring in various brain regions within and beyond the visual cortex. Recently-proposed accelerated fMRI techniques were employed for data acquisition, and procedures for exclusion of large draining vein contributions, together with ICA-assisted denoising, were included in the analysis to improve response estimation. Besides the visual cortex, significant PBRs were found in the lateral geniculate nucleus and superior colliculus, as well as the pre-central sulcus; in these regions, response durations increased monotonically with stimulus duration, in tight covariation with the visual PBR duration. Significant NBRs were found in the visual cortex, auditory cortex, default-mode network (DMN) and superior parietal lobule; NBR durations also tended to increase with stimulus duration, but were significantly less sustained than the visual PBR, especially for the DMN and superior parietal lobule. Responses in visual and auditory cortex were further studied for checkerboard contrast dependence, and their amplitudes were found to increase monotonically with contrast, linearly correlated with the visual PBR amplitude. Overall, these findings suggest the presence of dynamic neuronal interactions across multiple brain regions, sensitive to stimulus intensity and duration, and demonstrate the richness of information obtainable when jointly mapping positive and negative BOLD responses at a whole-brain scale, with ultra-high field fMRI. © 2018 Wiley Periodicals, Inc.

Comparison of Threshold Saccadic Vector Optokinetic Perimetry (SVOP) and Standard Automated Perimetry (SAP) in Glaucoma. Part II: Patterns of Visual Field Loss and Acceptability.

PubMed

McTrusty, Alice D; Cameron, Lorraine A; Perperidis, Antonios; Brash, Harry M; Tatham, Andrew J; Agarwal, Pankaj K; Murray, Ian C; Fleck, Brian W; Minns, Robert A

2017-09-01

We compared patterns of visual field loss detected by standard automated perimetry (SAP) to saccadic vector optokinetic perimetry (SVOP) and examined patient perceptions of each test. A cross-sectional study was done of 58 healthy subjects and 103 with glaucoma who were tested using SAP and two versions of SVOP (v1 and v2). Visual fields from both devices were categorized by masked graders as: 0, normal; 1, paracentral defect; 2, nasal step; 3, arcuate defect; 4, altitudinal; 5, biarcuate; and 6, end-stage field loss. SVOP and SAP classifications were cross-tabulated. Subjects completed a questionnaire on their opinions of each test. We analyzed 142 (v1) and 111 (v2) SVOP and SAP test pairs. SVOP v2 had a sensitivity of 97.7% and specificity of 77.9% for identifying normal versus abnormal visual fields. SAP and SVOP v2 classifications showed complete agreement in 54% of glaucoma patients, with a further 23% disagreeing by one category. On repeat testing, 86% of SVOP v2 classifications agreed with the previous test, compared to 91% of SAP classifications; 71% of subjects preferred SVOP compared to 20% who preferred SAP. Eye-tracking perimetry can be used to obtain threshold visual field sensitivity values in patients with glaucoma and produce maps of visual field defects, with patterns exhibiting close agreement to SAP. Patients preferred eye-tracking perimetry compared to SAP. This first report of threshold eye tracking perimetry shows good agreement with conventional automated perimetry and provides a benchmark for future iterations.

DeepSurveyCam--A Deep Ocean Optical Mapping System.

PubMed

Kwasnitschka, Tom; Köser, Kevin; Sticklus, Jan; Rothenbeck, Marcel; Weiß, Tim; Wenzlaff, Emanuel; Schoening, Timm; Triebe, Lars; Steinführer, Anja; Devey, Colin; Greinert, Jens

2016-01-28

Underwater photogrammetry and in particular systematic visual surveys of the deep sea are by far less developed than similar techniques on land or in space. The main challenges are the rough conditions with extremely high pressure, the accessibility of target areas (container and ship deployment of robust sensors, then diving for hours to the ocean floor), and the limitations of localization technologies (no GPS). The absence of natural light complicates energy budget considerations for deep diving flash-equipped drones. Refraction effects influence geometric image formation considerations with respect to field of view and focus, while attenuation and scattering degrade the radiometric image quality and limit the effective visibility. As an improvement on the stated issues, we present an AUV-based optical system intended for autonomous visual mapping of large areas of the seafloor (square kilometers) in up to 6000 m water depth. We compare it to existing systems and discuss tradeoffs such as resolution vs. mapped area and show results from a recent deployment with 90,000 mapped square meters of deep ocean floor.

Using Openstreetmap Data to Generate Building Models with Their Inner Structures for 3d Maps

NASA Astrophysics Data System (ADS)

Wang, Z.; Zipf, A.

2017-09-01

With the development of Web 2.0, more and more data related to indoor environments has been collected within the volunteered geographic information (VGI) framework, which creates a need for construction of indoor environments from VGI. In this study, we focus on generating 3D building models from OpenStreetMap (OSM) data, and provide an approach to support construction and visualization of indoor environments on 3D maps. In this paper, we present an algorithm which can extract building information from OSM data, and can construct building structures as well as inner building components (e.g., doors, rooms, and windows). A web application is built to support the processing and visualization of the building models on a 3D map. We test our approach with an indoor dataset collected from the field. The results show the feasibility of our approach and its potentials to provide support for a wide range of applications, such as indoor and outdoor navigation, urban planning, and incident management.

Novice to Expert Cognition During Geologic Bedrock Mapping

NASA Astrophysics Data System (ADS)

Petcovic, H. L.; Libarkin, J.; Hambrick, D. Z.; Baker, K. M.; Elkins, J. T.; Callahan, C. N.; Turner, S.; Rench, T. A.; LaDue, N.

2011-12-01

Bedrock geologic mapping is a complex and cognitively demanding task. Successful mapping requires domain-specific content knowledge, visuospatial ability, navigation through the field area, creating a mental model of the geology that is consistent with field data, and metacognition. Most post-secondary geology students in the United States receive training in geologic mapping, however, not much is known about the cognitive processes that underlie successful bedrock mapping, or about how these processes change with education and experience. To better understand cognition during geologic mapping, we conducted a 2-year research study in which 67 volunteers representing a range from undergraduate sophomore to 20+ years professional experience completed a suite of cognitive measures plus a 1-day bedrock mapping task in the Rocky Mountains, Montana, USA. In addition to participants' geologic maps and field notes, the cognitive suite included tests and questionnaires designed to measure: (1) prior geologic experience, via a self-report survey; (2) geologic content knowledge, via a modified version of the Geoscience Concept Inventory; (3) visuospatial ability, working memory capacity, and perceptual speed, via paper-and-pencil and computerized tests; (4) use of space and time during mapping via GPS tracking; and (5) problem-solving in the field via think-aloud audio logs during mapping and post-mapping semi-structured interviews. Data were examined for correlations between performance on the mapping task and other measures. We found that both geological knowledge and spatial visualization ability correlated positively with accuracy in the field mapping task. More importantly, we found a Visuospatial Ability × Geological Knowledge interaction, such that visuospatial ability positively predicted mapping performance at low, but not high, levels of geological knowledge. In other words, we found evidence to suggest that visuospatial ability mattered for bedrock mapping for the novices in our sample, but not for the experts. For experienced mappers, we found a significant correlation between GCI scores and the thoroughness with which they covered the map area, plus a relationship between speed and map accuracy such that faster mappers produced better maps. However, fast novice mappers tended to produce the worst maps. Successful mappers formed a mental model of the underlying geologic structure immediately to early in the mapping task, then spent field time collecting observations to confirm, disconfirm, or modify their initial model. In contrast, the least successful mappers (all inexperienced) rarely generated explanations or models of the underlying geologic structure in the field.

Visualizing Transcranial Direct Current Stimulation (tDCS) in vivo using Magnetic Resonance Imaging

NASA Astrophysics Data System (ADS)

Jog, Mayank Anant

Transcranial Direct Current Stimulation (tDCS) is a low-cost, non-invasive neuromodulation technique that has been shown to treat clinical symptoms as well as improve cognition. However, no techniques exist at the time of research to visualize tDCS currents in vivo. This dissertation presents the theoretical framework and experimental implementations of a novel MRI technique that enables non-invasive visualization of the tDCS electric current using magnetic field mapping. The first chapter establishes the feasibility of measuring magnetic fields induced by tDCS currents. The following chapter discusses the state of the art implementation that can measure magnetic field changes in individual subjects undergoing concurrent tDCS/MRI. The final chapter discusses how the developed technique was integrated with BOLD fMRI-an established MRI technique for measuring brain function. By enabling a concurrent measurement of the tDCS current induced magnetic field as well as the brain's hemodynamic response to tDCS, our technique opens a new avenue to investigate tDCS mechanisms and improve targeting.

Saccade Generation by the Frontal Eye Fields in Rhesus Monkeys Is Separable from Visual Detection and Bottom-Up Attention Shift

PubMed Central

Lee, Kyoung-Min; Ahn, Kyung-Ha; Keller, Edward L.

2012-01-01

The frontal eye fields (FEF), originally identified as an oculomotor cortex, have also been implicated in perceptual functions, such as constructing a visual saliency map and shifting visual attention. Further dissecting the area’s role in the transformation from visual input to oculomotor command has been difficult because of spatial confounding between stimuli and responses and consequently between intermediate cognitive processes, such as attention shift and saccade preparation. Here we developed two tasks in which the visual stimulus and the saccade response were dissociated in space (the extended memory-guided saccade task), and bottom-up attention shift and saccade target selection were independent (the four-alternative delayed saccade task). Reversible inactivation of the FEF in rhesus monkeys disrupted, as expected, contralateral memory-guided saccades, but visual detection was demonstrated to be intact at the same field. Moreover, saccade behavior was impaired when a bottom-up shift of attention was not a prerequisite for saccade target selection, indicating that the inactivation effect was independent of the previously reported dysfunctions in bottom-up attention control. These findings underscore the motor aspect of the area’s functions, especially in situations where saccades are generated by internal cognitive processes, including visual short-term memory and long-term associative memory. PMID:22761923

Saccade generation by the frontal eye fields in rhesus monkeys is separable from visual detection and bottom-up attention shift.

PubMed

Lee, Kyoung-Min; Ahn, Kyung-Ha; Keller, Edward L

2012-01-01

The frontal eye fields (FEF), originally identified as an oculomotor cortex, have also been implicated in perceptual functions, such as constructing a visual saliency map and shifting visual attention. Further dissecting the area's role in the transformation from visual input to oculomotor command has been difficult because of spatial confounding between stimuli and responses and consequently between intermediate cognitive processes, such as attention shift and saccade preparation. Here we developed two tasks in which the visual stimulus and the saccade response were dissociated in space (the extended memory-guided saccade task), and bottom-up attention shift and saccade target selection were independent (the four-alternative delayed saccade task). Reversible inactivation of the FEF in rhesus monkeys disrupted, as expected, contralateral memory-guided saccades, but visual detection was demonstrated to be intact at the same field. Moreover, saccade behavior was impaired when a bottom-up shift of attention was not a prerequisite for saccade target selection, indicating that the inactivation effect was independent of the previously reported dysfunctions in bottom-up attention control. These findings underscore the motor aspect of the area's functions, especially in situations where saccades are generated by internal cognitive processes, including visual short-term memory and long-term associative memory.

3DView: Space physics data visualizer

NASA Astrophysics Data System (ADS)

Génot, V.; Beigbeder, L.; Popescu, D.; Dufourg, N.; Gangloff, M.; Bouchemit, M.; Caussarieu, S.; Toniutti, J.-P.; Durand, J.; Modolo, R.; André, N.; Cecconi, B.; Jacquey, C.; Pitout, F.; Rouillard, A.; Pinto, R.; Erard, S.; Jourdane, N.; Leclercq, L.; Hess, S.; Khodachenko, M.; Al-Ubaidi, T.; Scherf, M.; Budnik, E.

2018-04-01

3DView creates visualizations of space physics data in their original 3D context. Time series, vectors, dynamic spectra, celestial body maps, magnetic field or flow lines, and 2D cuts in simulation cubes are among the variety of data representation enabled by 3DView. It offers direct connections to several large databases and uses VO standards; it also allows the user to upload data. 3DView's versatility covers a wide range of space physics contexts.

Seeing the soil through the net: an eye-opener on the soil map of the Flemish region (Belgium)

NASA Astrophysics Data System (ADS)

Dondeyne, Stefaan; Vanierschot, Laura; Langohr, Roger; Van Ranst, Eric; Deckers, Jozef; Oorts, Katrien

2017-04-01

A systematic soil survey of Belgium was conducted from 1948 to 1991. Field surveys were done at the detailed scale of 1:5000 with the final maps published at a 1:20,000 scale. The legend of these detailed soil maps (scale 1:20,000) has been converted to the 3rd edition of the international soil classification system 'World Reference Base for Soil Resources' (WRB). Over the last years, the government of the Flemish region made great efforts to make these maps, along with other environmental data, available to the general audience through the internet. The soil maps are widely used and consulted by researchers, teachers, land-use planners, environmental consultancy agencies and archaeologists. The maps can be downloaded and consulted in the viewer 'Visual Soil Explorer' ('Bodemverkenner'). To increase the legibility of the maps, we assembled a collection of photographs from soil profiles representing 923 soil types and 413 photos of related landscape settings. By clicking on a specific location in the 'Visual Soil Explorer', pictures of the corresponding soil type and landscape appear in a pop-up window, with a brief explanation about the soil properties. The collection of photographs of soil profiles cover almost 80% of the total area of the Flemish region, and include the 100 most common soil types. Our own teaching experience shows that these information layers are particular valuable for teaching soil geography and earth sciences in general. Overall, such visual information layers should contribute to a better interpretation of the soil maps and legacy soil data by serving as an eye-opener on the soil map to the wider community.

Use of nontraditional flight displays for the reduction of central visual overload in the cockpit

NASA Technical Reports Server (NTRS)

Weinstein, Lisa F.; Wickens, Christopher D.

1992-01-01

The use of nontraditional flight displays to reduce visual overload in the cockpit was investigated in a dual-task paradigm. Three flight displays (central, peripheral, and ecological) were used between subjects for the primary tasks, and the type of secondary task (object identification or motion judgment) and the presentation of the location of the task in the visual field (central or peripheral) were manipulated with groups. The two visual-spatial tasks were time-shared to study the possibility of a compatibility mapping between task type and task location. The ecological display was found to allow for the most efficient time-sharing.

Random waves in the brain: Symmetries and defect generation in the visual cortex

NASA Astrophysics Data System (ADS)

Schnabel, M.; Kaschube, M.; Löwel, S.; Wolf, F.

2007-06-01

How orientation maps in the visual cortex of the brain develop is a matter of long standing debate. Experimental and theoretical evidence suggests that their development represents an activity-dependent self-organization process. Theoretical analysis [1] exploring this hypothesis predicted that maps at an early developmental stage are realizations of Gaussian random fields exhibiting a rigorous lower bound for their densities of topological defects, called pinwheels. As a consequence, lower pinwheel densities, if observed in adult animals, are predicted to develop through the motion and annihilation of pinwheel pairs. Despite of being valid for a large class of developmental models this result depends on the symmetries of the models and thus of the predicted random field ensembles. In [1] invariance of the orientation map's statistical properties under independent space rotations and orientation shifts was assumed. However, full rotation symmetry appears to be broken by interactions of cortical neurons, e.g. selective couplings between groups of neurons with collinear orientation preferences [2]. A recently proposed new symmetry, called shift-twist symmetry [3], stating that spatial rotations have to occur together with orientation shifts in order to be an appropriate symmetry transformation, is more consistent with this organization. Here we generalize our random field approach to this important symmetry class. We propose a new class of shift-twist symmetric Gaussian random fields and derive the general correlation functions of this ensemble. It turns out that despite strong effects of the shift-twist symmetry on the structure of the correlation functions and on the map layout the lower bound on the pinwheel densities remains unaffected, predicting pinwheel annihilation in systems with low pinwheel densities.

Learning GIS and exploring geolocated data with the all-in-one Geolokit toolbox for Google Earth

NASA Astrophysics Data System (ADS)

Watlet, A.; Triantafyllou, A.; Bastin, C.

2016-12-01

GIS software are today's essential tools to gather and visualize geological data, to apply spatial and temporal analysis and finally, to create and share interactive maps for further investigations in geosciences. Such skills are especially essential to learn for students who go through fieldtrips, samples collections or field experiments. However, time is generally missing to teach in detail all the aspects of visualizing geolocated geoscientific data. For these purposes, we developed Geolokit: a lightweight freeware dedicated to geodata visualization and written in Python, a high-level, cross-platform programming language. Geolokit software is accessible through a graphical user interface, designed to run in parallel with Google Earth, benefitting from the numerous interactive capabilities. It is designed as a very user-friendly toolbox that allows `geo-users' to import their raw data (e.g. GPS, sample locations, structural data, field pictures, maps), to use fast data analysis tools and to visualize these into the Google Earth environment using KML code; with no require of third party software, except Google Earth itself. Geolokit comes with a large number of geosciences labels, symbols, colours and placemarks and is applicable to display several types of geolocated data, including: Multi-points datasets Automatically computed contours of multi-points datasets via several interpolation methods Discrete planar and linear structural geology data in 2D or 3D supporting large range of structures input format Clustered stereonets and rose diagrams 2D cross-sections as vertical sections Georeferenced maps and grids with user defined coordinates Field pictures using either geo-tracking metadata from a camera built-in GPS module, or the same-day track of an external GPS In the end, Geolokit is helpful for quickly visualizing and exploring data without losing too much time in the numerous capabilities of GIS software suites. We are looking for students and teachers to discover all the functionalities of Geolokit. As this project is under development and planned to be open source, we are definitely looking to discussions regarding particular needs or ideas, and to contributions in the Geolokit project.

Landslide inventory maps: New tools for an old problem

NASA Astrophysics Data System (ADS)

Guzzetti, Fausto; Mondini, Alessandro Cesare; Cardinali, Mauro; Fiorucci, Federica; Santangelo, Michele; Chang, Kang-Tsung

2012-04-01

Landslides are present in all continents, and play an important role in the evolution of landscapes. They also represent a serious hazard in many areas of the world. Despite their importance, we estimate that landslide maps cover less than 1% of the slopes in the landmasses, and systematic information on the type, abundance, and distribution of landslides is lacking. Preparing landslide maps is important to document the extent of landslide phenomena in a region, to investigate the distribution, types, pattern, recurrence and statistics of slope failures, to determine landslide susceptibility, hazard, vulnerability and risk, and to study the evolution of landscapes dominated by mass-wasting processes. Conventional methods for the production of landslide maps rely chiefly on the visual interpretation of stereoscopic aerial photography, aided by field surveys. These methods are time consuming and resource intensive. New and emerging techniques based on satellite, airborne, and terrestrial remote sensing technologies, promise to facilitate the production of landslide maps, reducing the time and resources required for their compilation and systematic update. In this work, we first outline the principles for landslide mapping, and we review the conventional methods for the preparation of landslide maps, including geomorphological, event, seasonal, and multi-temporal inventories. Next, we examine recent and new technologies for landslide mapping, considering (i) the exploitation of very-high resolution digital elevation models to analyze surface morphology, (ii) the visual interpretation and semi-automatic analysis of different types of satellite images, including panchromatic, multispectral, and synthetic aperture radar images, and (iii) tools that facilitate landslide field mapping. Next, we discuss the advantages and the limitations of the new remote sensing data and technology for the production of geomorphological, event, seasonal, and multi-temporal inventory maps. We conclude by arguing that the new tools will help to improve the quality of landslide maps, with positive effects on all derivative products and analyses, including erosion studies and landscape modeling, susceptibility and hazard assessments, and risk evaluations.

Visualization of system dynamics using phasegrams

PubMed Central

Herbst, Christian T.; Herzel, Hanspeter; Švec, Jan G.; Wyman, Megan T.; Fitch, W. Tecumseh

2013-01-01

A new tool for visualization and analysis of system dynamics is introduced: the phasegram. Its application is illustrated with both classical nonlinear systems (logistic map and Lorenz system) and with biological voice signals. Phasegrams combine the advantages of sliding-window analysis (such as the spectrogram) with well-established visualization techniques from the domain of nonlinear dynamics. In a phasegram, time is mapped onto the x-axis, and various vibratory regimes, such as periodic oscillation, subharmonics or chaos, are identified within the generated graph by the number and stability of horizontal lines. A phasegram can be interpreted as a bifurcation diagram in time. In contrast to other analysis techniques, it can be automatically constructed from time-series data alone: no additional system parameter needs to be known. Phasegrams show great potential for signal classification and can act as the quantitative basis for further analysis of oscillating systems in many scientific fields, such as physics (particularly acoustics), biology or medicine. PMID:23697715

3D Geo-Structures Visualization Education Project (3dgeostructuresvis.ucdavis.edu)

NASA Astrophysics Data System (ADS)

Billen, M. I.

2014-12-01

Students of field-based geology must master a suite of challenging skills from recognizing rocks, to measuring orientations of features in the field, to finding oneself (and the outcrop) on a map and placing structural information on maps. Students must then synthesize this information to derive meaning from the observations and ultimately to determine the three-dimensional (3D) shape of the deformed structures and their kinematic history. Synthesizing this kind of information requires sophisticated visualizations skills in order to extrapolate observations into the subsurface or missing (eroded) material. The good news is that students can learn 3D visualization skills through practice, and virtual tools can help provide some of that practice. Here I present a suite of learning modules focused at developing students' ability to imagine (visualize) complex 3D structures and their exposure through digital topographic surfaces. Using the software 3DVisualizer, developed by KeckCAVES (keckcaves.org) we have developed visualizations of common geologic structures (e.g., syncline, dipping fold) in which the rock is represented by originally flat-lying layers of sediment, each with a different color, which have been subsequently deformed. The exercises build up in complexity, first focusing on understanding the structure in 3D (penetrative understanding), and then moving to the exposure of the structure at a topographic surface. Individual layers can be rendered as a transparent feature to explore how the layer extends above and below the topographic surface (e.g., to follow an eroded fold limb across a valley). The exercises are provided using either movies of the visualization (which can also be used for examples during lectures), or the data and software can be downloaded to allow for more self-driven exploration and learning. These virtual field models and exercises can be used as "practice runs" before going into the field, as make-up assignments, as a field experience in regions without good geologic outcrops, or for students with disabilities that prevent them from going into the field. These exercises and modules are available from 3dgeostructuresvis.ucdavis.edu. We plan to add several new structures to the site each year. This project was funded by a National Science Foundation CAREER grant to Billen.

Improved method for retinotopy constrained source estimation of visual evoked responses

PubMed Central

Hagler, Donald J.; Dale, Anders M.

2011-01-01

Retinotopy constrained source estimation (RCSE) is a method for non-invasively measuring the time courses of activation in early visual areas using magnetoencephalography (MEG) or electroencephalography (EEG). Unlike conventional equivalent current dipole or distributed source models, the use of multiple, retinotopically-mapped stimulus locations to simultaneously constrain the solutions allows for the estimation of independent waveforms for visual areas V1, V2, and V3, despite their close proximity to each other. We describe modifications that improve the reliability and efficiency of this method. First, we find that increasing the number and size of visual stimuli results in source estimates that are less susceptible to noise. Second, to create a more accurate forward solution, we have explicitly modeled the cortical point spread of individual visual stimuli. Dipoles are represented as extended patches on the cortical surface, which take into account the estimated receptive field size at each location in V1, V2, and V3 as well as the contributions from contralateral, ipsilateral, dorsal, and ventral portions of the visual areas. Third, we implemented a map fitting procedure to deform a template to match individual subject retinotopic maps derived from functional magnetic resonance imaging (fMRI). This improves the efficiency of the overall method by allowing automated dipole selection, and it makes the results less sensitive to physiological noise in fMRI retinotopy data. Finally, the iteratively reweighted least squares (IRLS) method was used to reduce the contribution from stimulus locations with high residual error for robust estimation of visual evoked responses. PMID:22102418

Altering spatial priority maps via reward-based learning.

PubMed

Chelazzi, Leonardo; Eštočinová, Jana; Calletti, Riccardo; Lo Gerfo, Emanuele; Sani, Ilaria; Della Libera, Chiara; Santandrea, Elisa

2014-06-18

Spatial priority maps are real-time representations of the behavioral salience of locations in the visual field, resulting from the combined influence of stimulus driven activity and top-down signals related to the current goals of the individual. They arbitrate which of a number of (potential) targets in the visual scene will win the competition for attentional resources. As a result, deployment of visual attention to a specific spatial location is determined by the current peak of activation (corresponding to the highest behavioral salience) across the map. Here we report a behavioral study performed on healthy human volunteers, where we demonstrate that spatial priority maps can be shaped via reward-based learning, reflecting long-lasting alterations (biases) in the behavioral salience of specific spatial locations. These biases exert an especially strong influence on performance under conditions where multiple potential targets compete for selection, conferring competitive advantage to targets presented in spatial locations associated with greater reward during learning relative to targets presented in locations associated with lesser reward. Such acquired biases of spatial attention are persistent, are nonstrategic in nature, and generalize across stimuli and task contexts. These results suggest that reward-based attentional learning can induce plastic changes in spatial priority maps, endowing these representations with the "intelligent" capacity to learn from experience. Copyright © 2014 the authors 0270-6474/14/348594-11$15.00/0.

Real-Space Mapping of the Chiral Near-Field Distributions in Spiral Antennas and Planar Metasurfaces.

PubMed

Schnell, M; Sarriugarte, P; Neuman, T; Khanikaev, A B; Shvets, G; Aizpurua, J; Hillenbrand, R

2016-01-13

Chiral antennas and metasurfaces can be designed to react differently to left- and right-handed circularly polarized light, which enables novel optical properties such as giant optical activity and negative refraction. Here, we demonstrate that the underlying chiral near-field distributions can be directly mapped with scattering-type scanning near-field optical microscopy employing circularly polarized illumination. We apply our technique to visualize, for the first time, the circular-polarization selective nanofocusing of infrared light in Archimedean spiral antennas, and explain this chiral optical effect by directional launching of traveling waves in analogy to antenna theory. Moreover, we near-field image single-layer rosette and asymmetric dipole-monopole metasurfaces and find negligible and strong chiral optical near-field contrast, respectively. Our technique paves the way for near-field characterization of optical chirality in metal nanostructures, which will be essential for the future development of chiral antennas and metasurfaces and their applications.

Development of orientation tuning in simple cells of primary visual cortex

PubMed Central

Moore, Bartlett D.

2012-01-01

Orientation selectivity and its development are basic features of visual cortex. The original model of orientation selectivity proposes that elongated simple cell receptive fields are constructed from convergent input of an array of lateral geniculate nucleus neurons. However, orientation selectivity of simple cells in the visual cortex is generally greater than the linear contributions based on projections from spatial receptive field profiles. This implies that additional selectivity may arise from intracortical mechanisms. The hierarchical processing idea implies mainly linear connections, whereas cortical contributions are generally considered to be nonlinear. We have explored development of orientation selectivity in visual cortex with a focus on linear and nonlinear factors in a population of anesthetized 4-wk postnatal kittens and adult cats. Linear contributions are estimated from receptive field maps by which orientation tuning curves are generated and bandwidth is quantified. Nonlinear components are estimated as the magnitude of the power function relationship between responses measured from drifting sinusoidal gratings and those predicted from the spatial receptive field. Measured bandwidths for kittens are slightly larger than those in adults, whereas predicted bandwidths are substantially broader. These results suggest that relatively strong nonlinearities in early postnatal stages are substantially involved in the development of orientation tuning in visual cortex. PMID:22323631

Interactive Design and Visualization of Branched Covering Spaces.

PubMed

Roy, Lawrence; Kumar, Prashant; Golbabaei, Sanaz; Zhang, Yue; Zhang, Eugene

2018-01-01

Branched covering spaces are a mathematical concept which originates from complex analysis and topology and has applications in tensor field topology and geometry remeshing. Given a manifold surface and an -way rotational symmetry field, a branched covering space is a manifold surface that has an -to-1 map to the original surface except at the ramification points, which correspond to the singularities in the rotational symmetry field. Understanding the notion and mathematical properties of branched covering spaces is important to researchers in tensor field visualization and geometry processing, and their application areas. In this paper, we provide a framework to interactively design and visualize the branched covering space (BCS) of an input mesh surface and a rotational symmetry field defined on it. In our framework, the user can visualize not only the BCSs but also their construction process. In addition, our system allows the user to design the geometric realization of the BCS using mesh deformation techniques as well as connecting tubes. This enables the user to verify important facts about BCSs such as that they are manifold surfaces around singularities, as well as the Riemann-Hurwitz formula which relates the Euler characteristic of the BCS to that of the original mesh. Our system is evaluated by student researchers in scientific visualization and geometry processing as well as faculty members in mathematics at our university who teach topology. We include their evaluations and feedback in the paper.

Digital Soil Mapping - A platform for enhancing soil learning

NASA Astrophysics Data System (ADS)

Owens, Phillip; Libohova, Zamir; Monger, Curtis; Lindbo, David; Schmidt, Axel

2017-04-01

The expansion of digital infrastructure and tools has generated massive data and information as well as a need for reliable processing and accurate interpretations. Digital Soil Mapping is no exception in that it has provided opportunities for professionals and the public to interact at field and training/workshop levels in order to better understand soils and their benefits. USDA-NRCS National Cooperative Soil Survey regularly conducts training and workshops for soil scientists and other professionals in the US and internationally. A combination of field experiences with workshops conducted in a class environment offers ideal conditions for enhancing soil learning experiences. Examples from US, Haiti and Central America show that Digital Soil Mapping (DSM) tools are very effective for understanding and visualizing soils and their functioning at different scales.

Topographic Organization for Delayed Saccades in Human Posterior Parietal Cortex

PubMed Central

Schluppeck, Denis; Glimcher, Paul; Heeger, David J.

2008-01-01

Posterior parietal cortex (PPC) is thought to play a critical role in decision making, sensory attention, motor intention, and/or working memory. Research on the PPC in non-human primates has focused on the lateral intraparietal area (LIP) in the intraparietal sulcus (IPS). Neurons in LIP respond after the onset of visual targets, just before saccades to those targets, and during the delay period in between. To study the function of posterior parietal cortex in humans, it will be crucial to have a routine and reliable method for localizing specific parietal areas in individual subjects. Here, we show that human PPC contains at least two topographically organized regions, which are candidates for the human homologue of LIP. We mapped the topographic organization of human PPC for delayed (memory guided) saccades using fMRI. Subjects were instructed to fixate centrally while a peripheral target was briefly presented. After a further 3-s delay, subjects made a saccade to the remembered target location followed by a saccade back to fixation and a 1-s inter-trial interval. Targets appeared at successive locations “around the clock” (same eccentricity, ≈30° angular steps), to produce a traveling wave of activity in areas that are topographically organized. PPC exhibited topographic organization for delayed saccades. We defined two areas in each hemisphere that contained topographic maps of the contralateral visual field. These two areas were immediately rostral to V7 as defined by standard retinotopic mapping. The two areas were separated from each other and from V7 by reversals in visual field orientation. However, we leave open the possibility that these two areas will be further subdivided in future studies. Our results demonstrate that topographic maps tile the cortex continuously from V1 well into PPC. PMID:15817644

Early monocular defocus disrupts the normal development of receptive-field structure in V2 neurons of macaque monkeys.

PubMed

Tao, Xiaofeng; Zhang, Bin; Shen, Guofu; Wensveen, Janice; Smith, Earl L; Nishimoto, Shinji; Ohzawa, Izumi; Chino, Yuzo M

2014-10-08

Experiencing different quality images in the two eyes soon after birth can cause amblyopia, a developmental vision disorder. Amblyopic humans show the reduced capacity for judging the relative position of a visual target in reference to nearby stimulus elements (position uncertainty) and often experience visual image distortion. Although abnormal pooling of local stimulus information by neurons beyond striate cortex (V1) is often suggested as a neural basis of these deficits, extrastriate neurons in the amblyopic brain have rarely been studied using microelectrode recording methods. The receptive field (RF) of neurons in visual area V2 in normal monkeys is made up of multiple subfields that are thought to reflect V1 inputs and are capable of encoding the spatial relationship between local stimulus features. We created primate models of anisometropic amblyopia and analyzed the RF subfield maps for multiple nearby V2 neurons of anesthetized monkeys by using dynamic two-dimensional noise stimuli and reverse correlation methods. Unlike in normal monkeys, the subfield maps of V2 neurons in amblyopic monkeys were severely disorganized: subfield maps showed higher heterogeneity within each neuron as well as across nearby neurons. Amblyopic V2 neurons exhibited robust binocular suppression and the strength of the suppression was positively correlated with the degree of hereogeneity and the severity of amblyopia in individual monkeys. Our results suggest that the disorganized subfield maps and robust binocular suppression of amblyopic V2 neurons are likely to adversely affect the higher stages of cortical processing resulting in position uncertainty and image distortion. Copyright © 2014 the authors 0270-6474/14/3413840-15$15.00/0.

DeepFix: A Fully Convolutional Neural Network for Predicting Human Eye Fixations.

PubMed

Kruthiventi, Srinivas S S; Ayush, Kumar; Babu, R Venkatesh

2017-09-01

Understanding and predicting the human visual attention mechanism is an active area of research in the fields of neuroscience and computer vision. In this paper, we propose DeepFix, a fully convolutional neural network, which models the bottom-up mechanism of visual attention via saliency prediction. Unlike classical works, which characterize the saliency map using various hand-crafted features, our model automatically learns features in a hierarchical fashion and predicts the saliency map in an end-to-end manner. DeepFix is designed to capture semantics at multiple scales while taking global context into account, by using network layers with very large receptive fields. Generally, fully convolutional nets are spatially invariant-this prevents them from modeling location-dependent patterns (e.g., centre-bias). Our network handles this by incorporating a novel location-biased convolutional layer. We evaluate our model on multiple challenging saliency data sets and show that it achieves the state-of-the-art results.

Retinotopic mapping with Spin Echo BOLD at 7 Tesla

PubMed Central

Olman, Cheryl A.; Van de Moortele, Pierre-Francois; Schumacher, Jennifer F.; Guy, Joe; Uğurbil, Kâmil; Yacoub, Essa

2010-01-01

For blood oxygenation level-dependent (BOLD) functional MRI experiments, contrast-to-noise ratio (CNR) increases with increasing field strength for both gradient echo (GE) and spin echo (SE) BOLD techniques. However, susceptibility artifacts and non-uniform coil sensitivity profiles complicate large field-of-view fMRI experiments (e.g., experiments covering multiple visual areas instead of focusing on a single cortical region). Here, we use SE BOLD to acquire retinotopic mapping data in early visual areas, testing the feasibility of SE BOLD experiments spanning multiple cortical areas at 7 Tesla. We also use a recently developed method for normalizing signal intensity in T1-weighted anatomical images to enable automated segmentation of the cortical gray matter for scans acquired at 7T with either surface or volume coils. We find that the CNR of the 7T GE data (average single-voxel, single-scan stimulus coherence: 0.41) is almost twice that of the 3T GE BOLD data (average coherence: 0.25), with the CNR of the SE BOLD data (average coherence: 0.23) comparable to that of the 3T GE data. Repeated measurements in individual subjects find that maps acquired with 1.8 mm resolution at 3T and 7T with GE BOLD and at 7T with SE BOLD show no systematic differences in either the area or the boundary locations for V1, V2 and V3, demonstrating the feasibility of high-resolution SE BOLD experiments with good sensitivity throughout multiple visual areas. PMID:20656431

Geometric representation of spin correlations and applications to ultracold systems

NASA Astrophysics Data System (ADS)

Mukherjee, Rick; Mirasola, Anthony E.; Hollingsworth, Jacob; White, Ian G.; Hazzard, Kaden R. A.

2018-04-01

We provide a one-to-one map between the spin correlations and certain three-dimensional shapes, analogous to the map between single spins and Bloch vectors, and demonstrate its utility. Much as one can reason geometrically about dynamics using a Bloch vector—e.g., a magnetic field causes it to precess and dissipation causes it to shrink—one can reason similarly about the shapes we use to visualize correlations. This visualization demonstrates its usefulness by unveiling the hidden structure in the correlations. For example, seemingly complex correlation dynamics can be described as simple motions of the shapes. We demonstrate the simplicity of the dynamics, which is obscured in conventional analyses, by analyzing several physical systems of relevance to cold atoms.

Visual Simultaneous Localization And Mapping (VSLAM) methods applied to indoor 3D topographical and radiological mapping in real-time

NASA Astrophysics Data System (ADS)

Hautot, Felix; Dubart, Philippe; Bacri, Charles-Olivier; Chagneau, Benjamin; Abou-Khalil, Roger

2017-09-01

New developments in the field of robotics and computer vision enables to merge sensors to allow fast realtime localization of radiological measurements in the space/volume with near-real time radioactive sources identification and characterization. These capabilities lead nuclear investigations to a more efficient way for operators' dosimetry evaluation, intervention scenarii and risks mitigation and simulations, such as accidents in unknown potentially contaminated areas or during dismantling operations

Visual receptive field properties of cells in the optic tectum of the archer fish.

PubMed

Ben-Tov, Mor; Kopilevich, Ivgeny; Donchin, Opher; Ben-Shahar, Ohad; Giladi, Chen; Segev, Ronen

2013-08-01

The archer fish is well known for its extreme visual behavior in shooting water jets at prey hanging on vegetation above water. This fish is a promising model in the study of visual system function because it can be trained to respond to artificial targets and thus to provide valuable psychophysical data. Although much behavioral data have indeed been collected over the past two decades, little is known about the functional organization of the main visual area supporting this visual behavior, namely, the fish optic tectum. In this article we focus on a fundamental aspect of this functional organization and provide a detailed analysis of receptive field properties of cells in the archer fish optic tectum. Using extracellular measurements to record activities of single cells, we first measure their retinotectal mapping. We then determine their receptive field properties such as size, selectivity for stimulus direction and orientation, tuning for spatial frequency, and tuning for temporal frequency. Finally, on the basis of all these measurements, we demonstrate that optic tectum cells can be classified into three categories: orientation-tuned cells, direction-tuned cells, and direction-agnostic cells. Our results provide an essential basis for future investigations of information processing in the archer fish visual system.

GEOBIA For Land Use Mapping Using Worldview2 Image In Bengkak Village Coastal, Banyuwangi Regency, East Java

NASA Astrophysics Data System (ADS)

Alrassi, Fitzastri; Salim, Emil; Nina, Anastasia; Alwi, Luthfi; Danoedoro, Projo; Kamal, Muhammad

2016-11-01

The east coast of Banyuwangi regency has a diverse variety of land use such as ponds, mangroves, agricultural fields and settlements. WorldView-2 is a multispectral image with high spatial resolution that can display detailed information of land use. Geographic Object Based Image Analysis (GEOBIA) classification technique uses object segments as the smallest unit of analysis. The segmentation and classification process is not only based on spectral value of the image but also considering other elements of the image interpretation. This gives GEOBIA an opportunities and challenges in the mapping and monitoring of land use. This research aims to assess the GEOBIA classification method for generating the classification of land use in coastal areas of Banyuwangi. The result of this study is land use classification map produced by GEOBIA classification. We verified the accuracy of the resulted land use map by comparing the map with result from visual interpretation of the image that have been validated through field surveys. Variation of land use in most of the east coast of Banyuwangi regency is dominated by mangrove, agricultural fields, mixed farms, settlements and ponds.

In the eye of the beholder: the effect of rater variability and different rating scales on QTL mapping.

PubMed

Poland, Jesse A; Nelson, Rebecca J

2011-02-01

The agronomic importance of developing durably resistant cultivars has led to substantial research in the field of quantitative disease resistance (QDR) and, in particular, mapping quantitative trait loci (QTL) for disease resistance. The assessment of QDR is typically conducted by visual estimation of disease severity, which raises concern over the accuracy and precision of visual estimates. Although previous studies have examined the factors affecting the accuracy and precision of visual disease assessment in relation to the true value of disease severity, the impact of this variability on the identification of disease resistance QTL has not been assessed. In this study, the effects of rater variability and rating scales on mapping QTL for northern leaf blight resistance in maize were evaluated in a recombinant inbred line population grown under field conditions. The population of 191 lines was evaluated by 22 different raters using a direct percentage estimate, a 0-to-9 ordinal rating scale, or both. It was found that more experienced raters had higher precision and that using a direct percentage estimation of diseased leaf area produced higher precision than using an ordinal scale. QTL mapping was then conducted using the disease estimates from each rater using stepwise general linear model selection (GLM) and inclusive composite interval mapping (ICIM). For GLM, the same QTL were largely found across raters, though some QTL were only identified by a subset of raters. The magnitudes of estimated allele effects at identified QTL varied drastically, sometimes by as much as threefold. ICIM produced highly consistent results across raters and for the different rating scales in identifying the location of QTL. We conclude that, despite variability between raters, the identification of QTL was largely consistent among raters, particularly when using ICIM. However, care should be taken in estimating QTL allele effects, because this was highly variable and rater dependent.

Plasticity and stability of visual field maps in adult primary visual cortex

PubMed Central

Wandell, Brian A.; Smirnakis, Stelios M.

2010-01-01

Preface It is important to understand the balance between cortical plasticity and stability in various systems and spatial scales in the adult brain. We review measurements of adult plasticity in primary visual cortex (V1), a structure that has a key role in distributing visual information. There are claims of plasticity at multiple spatial scales in adult V1, but many inconsistencies in the data raise questions about the extent and nature of such plasticity. Understanding is further limited by a lack of quantitative models to guide the interpretation of the data. These problems limit efforts to translate research findings about adult cortical plasticity into significant clinical, educational and policy applications. PMID:19904279

Visualizando el desarrollo de la nanomedicina en México.

PubMed

Robles-Belmont, Eduardo; Gortari-Rabiela, Rebeca de; Galarza-Barrios, Pilar; Siqueiros-García, Jesús Mario; Ruiz-León, Alejandro Arnulfo

2017-01-01

In this article we present a set of different visualizations of Mexico's nanomedicine scientific production data. Visualizations were developed using different methodologies for data analysis and visualization such as social network analysis, geography of science maps, and complex network communities analysis. Results are a multi-dimensional overview of the evolution of nanomedicine in Mexico. Moreover, visualizations allowed to identify trends and patterns of collaboration at the national and international level. Trends are also found in the knowledge structure of themes and disciplines. Finally, we identified the scientific communities in Mexico that are responsible for the new knowledge production in this emergent field of science. Copyright: © 2017 SecretarÍa de Salud

Localization and Classification of Paddy Field Pests using a Saliency Map and Deep Convolutional Neural Network.

PubMed

Liu, Ziyi; Gao, Junfeng; Yang, Guoguo; Zhang, Huan; He, Yong

2016-02-11

We present a pipeline for the visual localization and classification of agricultural pest insects by computing a saliency map and applying deep convolutional neural network (DCNN) learning. First, we used a global contrast region-based approach to compute a saliency map for localizing pest insect objects. Bounding squares containing targets were then extracted, resized to a fixed size, and used to construct a large standard database called Pest ID. This database was then utilized for self-learning of local image features which were, in turn, used for classification by DCNN. DCNN learning optimized the critical parameters, including size, number and convolutional stride of local receptive fields, dropout ratio and the final loss function. To demonstrate the practical utility of using DCNN, we explored different architectures by shrinking depth and width, and found effective sizes that can act as alternatives for practical applications. On the test set of paddy field images, our architectures achieved a mean Accuracy Precision (mAP) of 0.951, a significant improvement over previous methods.

Localization and Classification of Paddy Field Pests using a Saliency Map and Deep Convolutional Neural Network

PubMed Central

Liu, Ziyi; Gao, Junfeng; Yang, Guoguo; Zhang, Huan; He, Yong

2016-01-01

We present a pipeline for the visual localization and classification of agricultural pest insects by computing a saliency map and applying deep convolutional neural network (DCNN) learning. First, we used a global contrast region-based approach to compute a saliency map for localizing pest insect objects. Bounding squares containing targets were then extracted, resized to a fixed size, and used to construct a large standard database called Pest ID. This database was then utilized for self-learning of local image features which were, in turn, used for classification by DCNN. DCNN learning optimized the critical parameters, including size, number and convolutional stride of local receptive fields, dropout ratio and the final loss function. To demonstrate the practical utility of using DCNN, we explored different architectures by shrinking depth and width, and found effective sizes that can act as alternatives for practical applications. On the test set of paddy field images, our architectures achieved a mean Accuracy Precision (mAP) of 0.951, a significant improvement over previous methods. PMID:26864172

A Quantitative Visual Mapping and Visualization Approach for Deep Ocean Floor Research

NASA Astrophysics Data System (ADS)

Hansteen, T. H.; Kwasnitschka, T.

2013-12-01

Geological fieldwork on the sea floor is still impaired by our inability to resolve features on a sub-meter scale resolution in a quantifiable reference frame and over an area large enough to reveal the context of local observations. In order to overcome these issues, we have developed an integrated workflow of visual mapping techniques leading to georeferenced data sets which we examine using state-of-the-art visualization technology to recreate an effective working style of field geology. We demonstrate a microbathymetrical workflow, which is based on photogrammetric reconstruction of ROV imagery referenced to the acoustic vehicle track. The advantage over established acoustical systems lies in the true three-dimensionality of the data as opposed to the perspective projection from above produced by downward looking mapping methods. A full color texture mosaic derived from the imagery allows studies at resolutions beyond the resolved geometry (usually one order of magnitude below the image resolution) while color gives additional clues, which can only be partly resolved in acoustic backscatter. The creation of a three-dimensional model changes the working style from the temporal domain of a video recording back to the spatial domain of a map. We examine these datasets using a custom developed immersive virtual visualization environment. The ARENA (Artificial Research Environment for Networked Analysis) features a (lower) hemispherical screen at a diameter of six meters, accommodating up to four scientists at once thus providing the ability to browse data interactively among a group of researchers. This environment facilitates (1) the development of spatial understanding analogue to on-land outcrop studies, (2) quantitative observations of seafloor morphology and physical parameters of its deposits, (3) more effective formulation and communication of working hypotheses.

Development of new mapping standards for geological surveys in Greenland

NASA Astrophysics Data System (ADS)

Mätzler, Eva; langley, Kirsty; Hollis, Julie; Heide-Jørgensen, Helene

2017-04-01

The current official topographic and geological maps of Greenland are in scale of 1:250:000 and 1:500.000 respectively, allowing only very limited amount of detail. The maps are outdated, and periglacial landscapes have changed significantly since the acquisition date. Hence, new affordable mapping products of high quality are in demand that can be available within a restricted time frame. In order to fulfill those demands a new mapping standard based on satellite imagery was developed, where classifications are mainly carried out with algorithms suitable for automatization. A Digital Elevation Model (ArcticDEM) was applied allowing examination of topographic and geological structures and 3D visualizing. Information on topographic features and lithology was extracted based on analysis of spectral characteristics from different multispectral data sources (Landsat 8, ASTER, WorldView-3) partly combined with the DEM. A first product is completed, and validation was carried out by field surveys. Field and remotely sensed data were integrated into a GIS database, and derived data will be freely available providing a valuable tool for planning and carrying out mineral exploration and other field activities. This study offers a method for generating up-to-date, low-cost and high quality mapping products suitable for Arctic regions, where accessibility is restricted due to remoteness and lack of infrastructure.

Visual Fast Mapping in School-Aged Children with Specific Language Impairment

ERIC Educational Resources Information Center

Alt, Mary

2013-01-01

Purpose: To determine whether children with specific language impairment (SLI) demonstrate impaired visual fast mapping skills compared with unimpaired peers and to test components of visual working memory that may contribute to a visual working memory deficit. Methods: Fifty children (25 SLI) played 2 computer-based visual fast mapping games…

Direct Electric Field Visualization in Semiconductor Planar Structures

DTIC Science & Technology

2006-12-01

electrical signal . The spectral response is determined by the detector characteristics and the operating temperature. The sensitivity of the material used ...to the Office of Management and Budget, Paperwork Reduction Project (0704-0188) Washington DC 20503. 1. AGENCY USE ONLY (Leave blank) 2. REPORT...words) A new technique for imaging the 2D transport of free charge in semiconductor structures is used to directly map electric field distributions

Decoding the cortical transformations for visually guided reaching in 3D space.

PubMed

Blohm, Gunnar; Keith, Gerald P; Crawford, J Douglas

2009-06-01

To explore the possible cortical mechanisms underlying the 3-dimensional (3D) visuomotor transformation for reaching, we trained a 4-layer feed-forward artificial neural network to compute a reach vector (output) from the visual positions of both the hand and target viewed from different eye and head orientations (inputs). The emergent properties of the intermediate layers reflected several known neurophysiological findings, for example, gain field-like modulations and position-dependent shifting of receptive fields (RFs). We performed a reference frame analysis for each individual network unit, simulating standard electrophysiological experiments, that is, RF mapping (unit input), motor field mapping, and microstimulation effects (unit outputs). At the level of individual units (in both intermediate layers), the 3 different electrophysiological approaches identified different reference frames, demonstrating that these techniques reveal different neuronal properties and suggesting that a comparison across these techniques is required to understand the neural code of physiological networks. This analysis showed fixed input-output relationships within each layer and, more importantly, within each unit. These local reference frame transformation modules provide the basic elements for the global transformation; their parallel contributions are combined in a gain field-like fashion at the population level to implement both the linear and nonlinear elements of the 3D visuomotor transformation.

D Modelling and Visualization Based on the Unity Game Engine - Advantages and Challenges

NASA Astrophysics Data System (ADS)

Buyuksalih, I.; Bayburt, S.; Buyuksalih, G.; Baskaraca, A. P.; Karim, H.; Rahman, A. A.

2017-11-01

3D City modelling is increasingly popular and becoming valuable tools in managing big cities. Urban and energy planning, landscape, noise-sewage modelling, underground mapping and navigation are among the applications/fields which really depend on 3D modelling for their effectiveness operations. Several research areas and implementation projects had been carried out to provide the most reliable 3D data format for sharing and functionalities as well as visualization platform and analysis. For instance, BIMTAS company has recently completed a project to estimate potential solar energy on 3D buildings for the whole Istanbul and now focussing on 3D utility underground mapping for a pilot case study. The research and implementation standard on 3D City Model domain (3D data sharing and visualization schema) is based on CityGML schema version 2.0. However, there are some limitations and issues in implementation phase for large dataset. Most of the limitations were due to the visualization, database integration and analysis platform (Unity3D game engine) as highlighted in this paper.

Topographic Independent Component Analysis reveals random scrambling of orientation in visual space

PubMed Central

Martinez-Garcia, Marina; Martinez, Luis M.

2017-01-01

Neurons at primary visual cortex (V1) in humans and other species are edge filters organized in orientation maps. In these maps, neurons with similar orientation preference are clustered together in iso-orientation domains. These maps have two fundamental properties: (1) retinotopy, i.e. correspondence between displacements at the image space and displacements at the cortical surface, and (2) a trade-off between good coverage of the visual field with all orientations and continuity of iso-orientation domains in the cortical space. There is an active debate on the origin of these locally continuous maps. While most of the existing descriptions take purely geometric/mechanistic approaches which disregard the network function, a clear exception to this trend in the literature is the original approach of Hyvärinen and Hoyer based on infomax and Topographic Independent Component Analysis (TICA). Although TICA successfully addresses a number of other properties of V1 simple and complex cells, in this work we question the validity of the orientation maps obtained from TICA. We argue that the maps predicted by TICA can be analyzed in the retinal space, and when doing so, it is apparent that they lack the required continuity and retinotopy. Here we show that in the orientation maps reported in the TICA literature it is easy to find examples of violation of the continuity between similarly tuned mechanisms in the retinal space, which suggest a random scrambling incompatible with the maps in primates. The new experiments in the retinal space presented here confirm this guess: TICA basis vectors actually follow a random salt-and-pepper organization back in the image space. Therefore, the interesting clusters found in the TICA topology cannot be interpreted as the actual cortical orientation maps found in cats, primates or humans. In conclusion, Topographic ICA does not reproduce cortical orientation maps. PMID:28640816

Topographic Independent Component Analysis reveals random scrambling of orientation in visual space.

PubMed

Martinez-Garcia, Marina; Martinez, Luis M; Malo, Jesús

2017-01-01

Neurons at primary visual cortex (V1) in humans and other species are edge filters organized in orientation maps. In these maps, neurons with similar orientation preference are clustered together in iso-orientation domains. These maps have two fundamental properties: (1) retinotopy, i.e. correspondence between displacements at the image space and displacements at the cortical surface, and (2) a trade-off between good coverage of the visual field with all orientations and continuity of iso-orientation domains in the cortical space. There is an active debate on the origin of these locally continuous maps. While most of the existing descriptions take purely geometric/mechanistic approaches which disregard the network function, a clear exception to this trend in the literature is the original approach of Hyvärinen and Hoyer based on infomax and Topographic Independent Component Analysis (TICA). Although TICA successfully addresses a number of other properties of V1 simple and complex cells, in this work we question the validity of the orientation maps obtained from TICA. We argue that the maps predicted by TICA can be analyzed in the retinal space, and when doing so, it is apparent that they lack the required continuity and retinotopy. Here we show that in the orientation maps reported in the TICA literature it is easy to find examples of violation of the continuity between similarly tuned mechanisms in the retinal space, which suggest a random scrambling incompatible with the maps in primates. The new experiments in the retinal space presented here confirm this guess: TICA basis vectors actually follow a random salt-and-pepper organization back in the image space. Therefore, the interesting clusters found in the TICA topology cannot be interpreted as the actual cortical orientation maps found in cats, primates or humans. In conclusion, Topographic ICA does not reproduce cortical orientation maps.

Attentional distribution in the visual field during same-different judgments as assessed by response competition.

PubMed

Pan, K; Eriksen, C W

1993-02-01

Judgments of same and different on a comparison task have been found to be subject to response competition if an irrelevant stimulus is presented in the display along with the target stimuli. For example, the reaction time for judging two letters the same is markedly increased if a different but irrelevant letter is also present in the display (C. W. Eriksen, O'Hara, & B. [A.] Eriksen, 1982). We have made use of this competition effect to map the visual attentional field in two dimensions. In two experiments, we varied the size of the attended area by varying the separation of the comparison stimuli. The boundaries of the attended area were mapped by varying the location of a response-competitive irrelevant noise letter. On this task, the attended area was found to be elliptical in shape, with the location of the target stimuli defining the major axis. The minor axis of the ellipse increased in direct proportion to increases in the major axis. Rather than interpret these field effects in terms of areas of enhanced processing, we propose that instead they represent the limits or failures in inhibition of competing stimulation.

A main path domain map as digital library interface

NASA Astrophysics Data System (ADS)

Demaine, Jeffrey

2009-01-01

The shift to electronic publishing of scientific journals is an opportunity for the digital library to provide non-traditional ways of accessing the literature. One method is to use citation metadata drawn from a collection of electronic journals to generate maps of science. These maps visualize the communication patterns in the collection, giving the user an easy-tograsp view of the semantic structure underlying the scientific literature. For this visualization to be understandable the complexity of the citation network must be reduced through an algorithm. This paper describes the Citation Pathfinder application and its integration into a prototype digital library. This application generates small-scale citation networks that expand upon the search results of the digital library. These domain maps are linked to the collection, creating an interface that is based on the communication patterns in science. The Main Path Analysis technique is employed to simplify these networks into linear, sequential structures. By identifying patterns that characterize the evolution of the research field, Citation Pathfinder uses citations to give users a deeper understanding of the scientific literature.

DeepSurveyCam—A Deep Ocean Optical Mapping System

PubMed Central

Kwasnitschka, Tom; Köser, Kevin; Sticklus, Jan; Rothenbeck, Marcel; Weiß, Tim; Wenzlaff, Emanuel; Schoening, Timm; Triebe, Lars; Steinführer, Anja; Devey, Colin; Greinert, Jens

2016-01-01

Underwater photogrammetry and in particular systematic visual surveys of the deep sea are by far less developed than similar techniques on land or in space. The main challenges are the rough conditions with extremely high pressure, the accessibility of target areas (container and ship deployment of robust sensors, then diving for hours to the ocean floor), and the limitations of localization technologies (no GPS). The absence of natural light complicates energy budget considerations for deep diving flash-equipped drones. Refraction effects influence geometric image formation considerations with respect to field of view and focus, while attenuation and scattering degrade the radiometric image quality and limit the effective visibility. As an improvement on the stated issues, we present an AUV-based optical system intended for autonomous visual mapping of large areas of the seafloor (square kilometers) in up to 6000 m water depth. We compare it to existing systems and discuss tradeoffs such as resolution vs. mapped area and show results from a recent deployment with 90,000 mapped square meters of deep ocean floor. PMID:26828495

Lack of oblique astigmatism in the chicken eye.

PubMed

Maier, Felix M; Howland, Howard C; Ohlendorf, Arne; Wahl, Siegfried; Schaeffel, Frank

2015-04-01

Primate eyes display considerable oblique off-axis astigmatism which could provide information on the sign of defocus that is needed for emmetropization. The pattern of peripheral astigmatism is not known in the chicken eye, a common model of myopia. Peripheral astigmatism was mapped out over the horizontal visual field in three chickens, 43 days old, and in three near emmetropic human subjects, average age 34.7years, using infrared photoretinoscopy. There were no differences in astigmatism between humans and chickens in the central visual field (chicks -0.35D, humans -0.65D, n.s.) but large differences in the periphery (i.e. astigmatism at 40° in the temporal visual field: humans -4.21D, chicks -0.63D, p<0.001, unpaired t-test). The lack of peripheral astigmatism in chicks was not due to differences in corneal shape. Perhaps related to their superior peripheral optics, we found that chickens had excellent visual performance also in the far periphery. Using an automated optokinetic nystagmus paradigm, no difference was observed in spatial visual performance with vision restricted to either the central 67° of the visual field or to the periphery beyond 67°. Accommodation was elicited by stimuli presented far out in the visual field. Transscleral images of single infrared LEDs showed no sign of peripheral astigmatism. The chick may be the first terrestrial vertebrate described to lack oblique astigmatism. Since corneal shape cannot account for the difference in astigmatism in humans and chicks, it must trace back to the design of the crystalline lens. The lack of peripheral astigmatism in chicks also excludes a role in emmetropization. Copyright © 2015 Elsevier Ltd. All rights reserved.

MEG/EEG Source Reconstruction, Statistical Evaluation, and Visualization with NUTMEG

PubMed Central

Dalal, Sarang S.; Zumer, Johanna M.; Guggisberg, Adrian G.; Trumpis, Michael; Wong, Daniel D. E.; Sekihara, Kensuke; Nagarajan, Srikantan S.

2011-01-01

NUTMEG is a source analysis toolbox geared towards cognitive neuroscience researchers using MEG and EEG, including intracranial recordings. Evoked and unaveraged data can be imported to the toolbox for source analysis in either the time or time-frequency domains. NUTMEG offers several variants of adaptive beamformers, probabilistic reconstruction algorithms, as well as minimum-norm techniques to generate functional maps of spatiotemporal neural source activity. Lead fields can be calculated from single and overlapping sphere head models or imported from other software. Group averages and statistics can be calculated as well. In addition to data analysis tools, NUTMEG provides a unique and intuitive graphical interface for visualization of results. Source analyses can be superimposed onto a structural MRI or headshape to provide a convenient visual correspondence to anatomy. These results can also be navigated interactively, with the spatial maps and source time series or spectrogram linked accordingly. Animations can be generated to view the evolution of neural activity over time. NUTMEG can also display brain renderings and perform spatial normalization of functional maps using SPM's engine. As a MATLAB package, the end user may easily link with other toolboxes or add customized functions. PMID:21437174

MEG/EEG source reconstruction, statistical evaluation, and visualization with NUTMEG.

PubMed

Dalal, Sarang S; Zumer, Johanna M; Guggisberg, Adrian G; Trumpis, Michael; Wong, Daniel D E; Sekihara, Kensuke; Nagarajan, Srikantan S

2011-01-01

NUTMEG is a source analysis toolbox geared towards cognitive neuroscience researchers using MEG and EEG, including intracranial recordings. Evoked and unaveraged data can be imported to the toolbox for source analysis in either the time or time-frequency domains. NUTMEG offers several variants of adaptive beamformers, probabilistic reconstruction algorithms, as well as minimum-norm techniques to generate functional maps of spatiotemporal neural source activity. Lead fields can be calculated from single and overlapping sphere head models or imported from other software. Group averages and statistics can be calculated as well. In addition to data analysis tools, NUTMEG provides a unique and intuitive graphical interface for visualization of results. Source analyses can be superimposed onto a structural MRI or headshape to provide a convenient visual correspondence to anatomy. These results can also be navigated interactively, with the spatial maps and source time series or spectrogram linked accordingly. Animations can be generated to view the evolution of neural activity over time. NUTMEG can also display brain renderings and perform spatial normalization of functional maps using SPM's engine. As a MATLAB package, the end user may easily link with other toolboxes or add customized functions.

Combined theory of reflectance and emittance spectroscopy

NASA Technical Reports Server (NTRS)

Hapke, Bruce

1995-01-01

The theory in which either or both reflected sunlight and thermally emitted radiation contribute to the power received by a detector viewing a particulate medium, such as a powder in the laboratory or a planetary regolith, is considered theoretically. This theory is of considerable interest for the interpretation of data from field or spacecraft instruments that are sensitive to the near-infrared region of the spectrum, such as NIMS (near-infrared mapping spectrometer) and VIMS (visual and infrared mapping spectrometer), as well as thermal infrared detectors.

[application of the analytical transmission electron microscopy techniques for detection, identification and visualization of localization of nanoparticles of titanium and cerium oxides in mammalian cells].

PubMed

Shebanova, A S; Bogdanov, A G; Ismagulova, T T; Feofanov, A V; Semenyuk, P I; Muronets, V I; Erokhina, M V; Onishchenko, G E; Kirpichnikov, M P; Shaitan, K V

2014-01-01

This work represents the results of the study on applicability of the modern methods of analytical transmission electron microscopy for detection, identification and visualization of localization of nanoparticles of titanium and cerium oxides in A549 cell, human lung adenocarcinoma cell line. A comparative analysis of images of the nanoparticles in the cells obtained in the bright field mode of transmission electron microscopy, under dark-field scanning transmission electron microscopy and high-angle annular dark field scanning transmission electron was performed. For identification of nanoparticles in the cells the analytical techniques, energy-dispersive X-ray spectroscopy and electron energy loss spectroscopy, were compared when used in the mode of obtaining energy spectrum from different particles and element mapping. It was shown that the method for electron tomography is applicable to confirm that nanoparticles are localized in the sample but not coated by contamination. The possibilities and fields of utilizing different techniques for analytical transmission electron microscopy for detection, visualization and identification of nanoparticles in the biological samples are discussed.

Neurally Constrained Modeling of Perceptual Decision Making

ERIC Educational Resources Information Center

Purcell, Braden A.; Heitz, Richard P.; Cohen, Jeremiah Y.; Schall, Jeffrey D.; Logan, Gordon D.; Palmeri, Thomas J.

2010-01-01

Stochastic accumulator models account for response time in perceptual decision-making tasks by assuming that perceptual evidence accumulates to a threshold. The present investigation mapped the firing rate of frontal eye field (FEF) visual neurons onto perceptual evidence and the firing rate of FEF movement neurons onto evidence accumulation to…

a Model Study of Small-Scale World Map Generalization

NASA Astrophysics Data System (ADS)

Cheng, Y.; Yin, Y.; Li, C. M.; Wu, W.; Guo, P. P.; Ma, X. L.; Hu, F. M.

2018-04-01

With the globalization and rapid development every filed is taking an increasing interest in physical geography and human economics. There is a surging demand for small scale world map in large formats all over the world. Further study of automated mapping technology, especially the realization of small scale production on a large scale global map, is the key of the cartographic field need to solve. In light of this, this paper adopts the improved model (with the map and data separated) in the field of the mapmaking generalization, which can separate geographic data from mapping data from maps, mainly including cross-platform symbols and automatic map-making knowledge engine. With respect to the cross-platform symbol library, the symbol and the physical symbol in the geographic information are configured at all scale levels. With respect to automatic map-making knowledge engine consists 97 types, 1086 subtypes, 21845 basic algorithm and over 2500 relevant functional modules.In order to evaluate the accuracy and visual effect of our model towards topographic maps and thematic maps, we take the world map generalization in small scale as an example. After mapping generalization process, combining and simplifying the scattered islands make the map more explicit at 1 : 2.1 billion scale, and the map features more complete and accurate. Not only it enhance the map generalization of various scales significantly, but achieve the integration among map-makings of various scales, suggesting that this model provide a reference in cartographic generalization for various scales.

Exploring gravitational lensing model variations in the Frontier Fields galaxy clusters

NASA Astrophysics Data System (ADS)

Harris James, Nicholas John; Raney, Catie; Brennan, Sean; Keeton, Charles

2018-01-01

Multiple groups have been working on modeling the mass distributions of the six lensing galaxy clusters in the Hubble Space Telescope Frontier Fields data set. The magnification maps produced from these mass models will be important for the future study of the lensed background galaxies, but there exists significant variation in the different groups’ models and magnification maps. We explore the use of two-dimensional histograms as a tool for visualizing these magnification map variations. Using a number of simple, one- or two-halo singular isothermal sphere models, we explore the features that are produced in 2D histogram model comparisons when parameters such as halo mass, ellipticity, and location are allowed to vary. Our analysis demonstrates the potential of 2D histograms as a means of observing the full range of differences between the Frontier Fields groups’ models.This work has been supported by funding from National Science Foundation grants PHY-1560077 and AST-1211385, and from the Space Telescope Science Institute.

From Open Geographical Data to Tangible Maps: Improving the Accessibility of Maps for Visually Impaired People

NASA Astrophysics Data System (ADS)

Ducasse, J.; Macé, M.; Jouffrais, C.

2015-08-01

Visual maps must be transcribed into (interactive) raised-line maps to be accessible for visually impaired people. However, these tactile maps suffer from several shortcomings: they are long and expensive to produce, they cannot display a large amount of information, and they are not dynamically modifiable. A number of methods have been developed to automate the production of raised-line maps, but there is not yet any tactile map editor on the market. Tangible interactions proved to be an efficient way to help a visually impaired user manipulate spatial representations. Contrary to raised-line maps, tangible maps can be autonomously constructed and edited. In this paper, we present the scenarios and the main expected contributions of the AccessiMap project, which is based on the availability of many sources of open spatial data: 1/ facilitating the production of interactive tactile maps with the development of an open-source web-based editor; 2/ investigating the use of tangible interfaces for the autonomous construction and exploration of a map by a visually impaired user.

Brain electric microstates and momentary conscious mind states as building blocks of spontaneous thinking: I. Visual imagery and abstract thoughts.

PubMed

Lehmann, D; Strik, W K; Henggeler, B; Koenig, T; Koukkou, M

1998-06-01

Prompted reports of recall of spontaneous, conscious experiences were collected in a no-input, no-task, no-response paradigm (30 random prompts to each of 13 healthy volunteers). The mentation reports were classified into visual imagery and abstract thought. Spontaneous 19-channel brain electric activity (EEG) was continuously recorded, viewed as series of momentary spatial distributions (maps) of the brain electric field and segmented into microstates, i.e. into time segments characterized by quasi-stable landscapes of potential distribution maps which showed varying durations in the sub-second range. Microstate segmentation used a data-driven strategy. Different microstates, i.e. different brain electric landscapes must have been generated by activity of different neural assemblies and therefore are hypothesized to constitute different functions. The two types of reported experiences were associated with significantly different microstates (mean duration 121 ms) immediately preceding the prompts; these microstates showed, across subjects, for abstract thought (compared to visual imagery) a shift of the electric gravity center to the left and a clockwise rotation of the field axis. Contrariwise, the microstates 2 s before the prompt did not differ between the two types of experiences. The results support the hypothesis that different microstates of the brain as recognized in its electric field implement different conscious, reportable mind states, i.e. different classes (types) of thoughts (mentations); thus, the microstates might be candidates for the 'atoms of thought'.

DBMap: a TreeMap-based framework for data navigation and visualization of brain research registry

NASA Astrophysics Data System (ADS)

Zhang, Ming; Zhang, Hong; Tjandra, Donny; Wong, Stephen T. C.

2003-05-01

The purpose of this study is to investigate and apply a new, intuitive and space-conscious visualization framework to facilitate efficient data presentation and exploration of large-scale data warehouses. We have implemented the DBMap framework for the UCSF Brain Research Registry. Such a novel utility would facilitate medical specialists and clinical researchers in better exploring and evaluating a number of attributes organized in the brain research registry. The current UCSF Brain Research Registry consists of a federation of disease-oriented database modules, including Epilepsy, Brain Tumor, Intracerebral Hemorrphage, and CJD (Creuzfeld-Jacob disease). These database modules organize large volumes of imaging and non-imaging data to support Web-based clinical research. While the data warehouse supports general information retrieval and analysis, there lacks an effective way to visualize and present the voluminous and complex data stored. This study investigates whether the TreeMap algorithm can be adapted to display and navigate categorical biomedical data warehouse or registry. TreeMap is a space constrained graphical representation of large hierarchical data sets, mapped to a matrix of rectangles, whose size and color represent interested database fields. It allows the display of a large amount of numerical and categorical information in limited real estate of computer screen with an intuitive user interface. The paper will describe, DBMap, the proposed new data visualization framework for large biomedical databases. Built upon XML, Java and JDBC technologies, the prototype system includes a set of software modules that reside in the application server tier and provide interface to backend database tier and front-end Web tier of the brain registry.

Cross-modal metaphorical mapping of spoken emotion words onto vertical space.

PubMed

Montoro, Pedro R; Contreras, María José; Elosúa, María Rosa; Marmolejo-Ramos, Fernando

2015-01-01

From the field of embodied cognition, previous studies have reported evidence of metaphorical mapping of emotion concepts onto a vertical spatial axis. Most of the work on this topic has used visual words as the typical experimental stimuli. However, to our knowledge, no previous study has examined the association between affect and vertical space using a cross-modal procedure. The current research is a first step toward the study of the metaphorical mapping of emotions onto vertical space by means of an auditory to visual cross-modal paradigm. In the present study, we examined whether auditory words with an emotional valence can interact with the vertical visual space according to a 'positive-up/negative-down' embodied metaphor. The general method consisted in the presentation of a spoken word denoting a positive/negative emotion prior to the spatial localization of a visual target in an upper or lower position. In Experiment 1, the spoken words were passively heard by the participants and no reliable interaction between emotion concepts and bodily simulated space was found. In contrast, Experiment 2 required more active listening of the auditory stimuli. A metaphorical mapping of affect and space was evident but limited to the participants engaged in an emotion-focused task. Our results suggest that the association of affective valence and vertical space is not activated automatically during speech processing since an explicit semantic and/or emotional evaluation of the emotionally valenced stimuli was necessary to obtain an embodied effect. The results are discussed within the framework of the embodiment hypothesis.

Cross-modal metaphorical mapping of spoken emotion words onto vertical space

PubMed Central

Montoro, Pedro R.; Contreras, María José; Elosúa, María Rosa; Marmolejo-Ramos, Fernando

2015-01-01

From the field of embodied cognition, previous studies have reported evidence of metaphorical mapping of emotion concepts onto a vertical spatial axis. Most of the work on this topic has used visual words as the typical experimental stimuli. However, to our knowledge, no previous study has examined the association between affect and vertical space using a cross-modal procedure. The current research is a first step toward the study of the metaphorical mapping of emotions onto vertical space by means of an auditory to visual cross-modal paradigm. In the present study, we examined whether auditory words with an emotional valence can interact with the vertical visual space according to a ‘positive-up/negative-down’ embodied metaphor. The general method consisted in the presentation of a spoken word denoting a positive/negative emotion prior to the spatial localization of a visual target in an upper or lower position. In Experiment 1, the spoken words were passively heard by the participants and no reliable interaction between emotion concepts and bodily simulated space was found. In contrast, Experiment 2 required more active listening of the auditory stimuli. A metaphorical mapping of affect and space was evident but limited to the participants engaged in an emotion-focused task. Our results suggest that the association of affective valence and vertical space is not activated automatically during speech processing since an explicit semantic and/or emotional evaluation of the emotionally valenced stimuli was necessary to obtain an embodied effect. The results are discussed within the framework of the embodiment hypothesis. PMID:26322007

The neurobiological basis of seeing words

PubMed Central

Wandell, Brian A.

2011-01-01

This review summarizes recent ideas about the cortical circuits for seeing words, an important part of the brain system for reading. Historically, the link between the visual cortex and reading has been contentious. One influential position is that the visual cortex plays a minimal role, limited to identifying contours, and that information about these contours is delivered to cortical regions specialized for reading and language. An alternative position is that specializations for seeing words develop within the visual cortex itself. Modern neuroimaging measurements—including both functional magnetic resonance imaging (fMRI) and diffusion weighted imaging with tractography data—support the position that circuitry for seeing the statistical regularities of word forms develops within the ventral occipitotemporal cortex, which also contains important circuitry for seeing faces, colors, and forms. The review explains new findings about the visual pathways, including visual field maps, as well as new findings about how we see words. The measurements from the two fields are in close cortical proximity, and there are good opportunities for coordinating theoretical ideas about function in the ventral occipitotemporal cortex. PMID:21486296

The neurobiological basis of seeing words.

PubMed

Wandell, Brian A

2011-04-01

This review summarizes recent ideas about the cortical circuits for seeing words, an important part of the brain system for reading. Historically, the link between the visual cortex and reading has been contentious. One influential position is that the visual cortex plays a minimal role, limited to identifying contours, and that information about these contours is delivered to cortical regions specialized for reading and language. An alternative position is that specializations for seeing words develop within the visual cortex itself. Modern neuroimaging measurements-including both functional magnetic resonance imaging (fMRI) and diffusion weighted imaging with tractography (DTI) data-support the position that circuitry for seeing the statistical regularities of word forms develops within the ventral occipitotemporal cortex, which also contains important circuitry for seeing faces, colors, and forms. This review explains new findings about the visual pathways, including visual field maps, as well as new findings about how we see words. The measurements from the two fields are in close cortical proximity, and there are good opportunities for coordinating theoretical ideas about function in the ventral occipitotemporal cortex. © 2011 New York Academy of Sciences.

Computer vision enhances mobile eye-tracking to expose expert cognition in natural-scene visual-search tasks

NASA Astrophysics Data System (ADS)

Keane, Tommy P.; Cahill, Nathan D.; Tarduno, John A.; Jacobs, Robert A.; Pelz, Jeff B.

2014-02-01

Mobile eye-tracking provides the fairly unique opportunity to record and elucidate cognition in action. In our research, we are searching for patterns in, and distinctions between, the visual-search performance of experts and novices in the geo-sciences. Traveling to regions resultant from various geological processes as part of an introductory field studies course in geology, we record the prima facie gaze patterns of experts and novices when they are asked to determine the modes of geological activity that have formed the scene-view presented to them. Recording eye video and scene video in natural settings generates complex imagery that requires advanced applications of computer vision research to generate registrations and mappings between the views of separate observers. By developing such mappings, we could then place many observers into a single mathematical space where we can spatio-temporally analyze inter- and intra-subject fixations, saccades, and head motions. While working towards perfecting these mappings, we developed an updated experiment setup that allowed us to statistically analyze intra-subject eye-movement events without the need for a common domain. Through such analyses we are finding statistical differences between novices and experts in these visual-search tasks. In the course of this research we have developed a unified, open-source, software framework for processing, visualization, and interaction of mobile eye-tracking and high-resolution panoramic imagery.

Bedmap2; Mapping, visualizing and communicating the Antarctic sub-glacial environment.

NASA Astrophysics Data System (ADS)

Fretwell, Peter; Pritchard, Hamish

2013-04-01

Bedmap2; Mapping, visualizing and communicating the Antarctic sub-glacial environment. The Bedmap2 project has been a large cooperative effort to compile, model, map and visualize the ice-rock interface beneath the Antarctic ice sheet. Here we present the final output of that project; the Bedmap2 printed map. The map is an A1, double sided print, showing 2d and 3d visualizations of the dataset. It includes scientific interpretations, cross sections and comparisons with other areas. Paper copies of the colour double sided map will be freely distributed at this session.

Sinking Maps: A Conceptual Tool for Visual Metaphor

ERIC Educational Resources Information Center

Giampa, Joan Marie

2012-01-01

Sinking maps, created by Northern Virginia Community College professor Joan Marie Giampa, are tools that teach fine art students how to construct visual metaphor by conceptually mapping sensory perceptions. Her dissertation answers the question, "Can visual metaphor be conceptually mapped in the art classroom?" In the Prologue, Giampa…

Diffusion-Based Density-Equalizing Maps: an Interdisciplinary Approach to Visualizing Homicide Rates and Other Georeferenced Statistical Data

NASA Astrophysics Data System (ADS)

Mazzitello, Karina I.; Candia, Julián

2012-12-01

In every country, public and private agencies allocate extensive funding to collect large-scale statistical data, which in turn are studied and analyzed in order to determine local, regional, national, and international policies regarding all aspects relevant to the welfare of society. One important aspect of that process is the visualization of statistical data with embedded geographical information, which most often relies on archaic methods such as maps colored according to graded scales. In this work, we apply nonstandard visualization techniques based on physical principles. We illustrate the method with recent statistics on homicide rates in Brazil and their correlation to other publicly available data. This physics-based approach provides a novel tool that can be used by interdisciplinary teams investigating statistics and model projections in a variety of fields such as economics and gross domestic product research, public health and epidemiology, sociodemographics, political science, business and marketing, and many others.

High-resolution in-situ thermal imaging of microbial mats at El Tatio Geyser, Chile shows coupling between community color and temperature

NASA Astrophysics Data System (ADS)

Dunckel, Anne E.; Cardenas, M. Bayani; Sawyer, Audrey H.; Bennett, Philip C.

2009-12-01

Microbial mats have spatially heterogeneous structured communities that manifest visually through vibrant color zonation often associated with environmental gradients. We report the first use of high-resolution thermal infrared imaging to map temperature at four hot springs within the El Tatio Geyser Field, Chile. Thermal images with millimeter resolution show drastic variability and pronounced patterning in temperature, with changes on the order of 30°C within a square decimeter. Paired temperature and visual images show that zones with specific coloration occur within distinct temperature ranges. Unlike previous studies where maximum, minimum, and optimal temperatures for microorganisms are based on isothermally-controlled laboratory cultures, thermal imaging allows for mapping thousands of temperature values in a natural setting. This allows for efficiently constraining natural temperature bounds for visually distinct mat zones. This approach expands current understanding of thermophilic microbial communities and opens doors for detailed analysis of biophysical controls on microbial ecology.

Mapping the evolution of entrepreneurship as a field of research (1990-2013): A scientometric analysis.

PubMed

Chandra, Yanto

2018-01-01

This article applies scientometric techniques to study the evolution of the field of entrepreneurship between 1990 and 2013. Using a combination of topic mapping, author and journal co-citation analyses, and overlay visualization of new and hot topics in the field, this article makes important contribution to the entrepreneurship research by identifying 46 topics in the 24-year history of entrepreneurship research and demonstrates how they appear, disappear, reappear and stabilize over time. It also identifies five topics that are persistent across the 24-year study period--institutions and institutional entrepreneurship, innovation and technology management, policy and development, entrepreneurial process and opportunity, and new ventures--which I labeled as The Pentagon of Entrepreneurship. Overall, the analyses revealed patterns of convergence and divergence and the diversity of topics, specialization, and interdisciplinary engagement in entrepreneurship research, thus offering the latest insights on the state of the art of the field.

Reflectance measurements for the detection and mapping of soil limitations

NASA Technical Reports Server (NTRS)

Benson, L. A.; Frazee, C. J.

1973-01-01

During 1971 and 1972 research was conducted on two fallow fields in the proposed Oahe Irrigation Project to investigate the relationship between the tonal variations observed on aerial photographs and the principal soil limitations of the area. A grid sampling procedure was used to collected detailed field data during the 1972 growing season. The field data was compared to imagery collected on May 14, 1971 at 3050 meters altitude. The imagery and field data were initially evaluated by a visual analysis. Correlation and regression analysis revealed a highly significant correlation and regression analysis revealed a highly significant correlation between the digitized color infrared film data and soil properties such as organic matter content, color, depth to carbonates, bulk density and reflectivity. Computer classification of the multiemulsion film data resulted in maps delineating the areas containing claypan and erosion limitations. Reflectance data from the red spectral band provided the best results.

Gradual plasmon evolution and huge infrared near-field enhancement of metallic bridged nanoparticle dimers.

PubMed

Huang, Yu; Ma, Lingwei; Hou, Mengjing; Xie, Zheng; Zhang, Zhengjun

2016-01-28

By three-dimensional (3D) finite element method (FEM) plasmon mapping, gradual plasmon evolutions of both bonding dipole plasmon (BDP) and charge transfer plasmon (CTP) modes are visualized. In particular, the evolved BDP mode provides a physical insight into the rapid degeneration of electromagnetic hot spots in practical applications, while the rising CTP mode enables a huge near-field enhancement for potential plasmonic devices at infrared wavelengths.

Predicted contextual modulation varies with distance from pinwheel centers in the orientation preference map

PubMed Central

Okamoto, Tsuyoshi; Ikezoe, Koji; Tamura, Hiroshi; Watanabe, Masataka; Aihara, Kazuyuki; Fujita, Ichiro

2011-01-01

In the primary visual cortex (V1) of some mammals, columns of neurons with the full range of orientation preferences converge at the center of a pinwheel-like arrangement, the ‘pinwheel center' (PWC). Because a neuron receives abundant inputs from nearby neurons, the neuron's position on the cortical map likely has a significant impact on its responses to the layout of orientations inside and outside its classical receptive field (CRF). To understand the positional specificity of responses, we constructed a computational model based on orientation preference maps in monkey V1 and hypothetical neuronal connections. The model simulations showed that neurons near PWCs displayed weaker but detectable orientation selectivity within their CRFs, and strongly reduced contextual modulation from extra-CRF stimuli, than neurons distant from PWCs. We suggest that neurons near PWCs robustly extract local orientation within their CRF embedded in visual scenes, and that contextual information is processed in regions distant from PWCs. PMID:22355631

Spatial-area selective retrieval of multiple object-place associations in a hierarchical cognitive map formed by theta phase coding.

PubMed

Sato, Naoyuki; Yamaguchi, Yoko

2009-06-01

The human cognitive map is known to be hierarchically organized consisting of a set of perceptually clustered landmarks. Patient studies have demonstrated that these cognitive maps are maintained by the hippocampus, while the neural dynamics are still poorly understood. The authors have shown that the neural dynamic "theta phase precession" observed in the rodent hippocampus may be capable of forming hierarchical cognitive maps in humans. In the model, a visual input sequence consisting of object and scene features in the central and peripheral visual fields, respectively, results in the formation of a hierarchical cognitive map for object-place associations. Surprisingly, it is possible for such a complex memory structure to be formed in a few seconds. In this paper, we evaluate the memory retrieval of object-place associations in the hierarchical network formed by theta phase precession. The results show that multiple object-place associations can be retrieved with the initial cue of a scene input. Importantly, according to the wide-to-narrow unidirectional connections among scene units, the spatial area for object-place retrieval can be controlled by the spatial area of the initial cue input. These results indicate that the hierarchical cognitive maps have computational advantages on a spatial-area selective retrieval of multiple object-place associations. Theta phase precession dynamics is suggested as a fundamental neural mechanism of the human cognitive map.

Multiple Concurrent Visual-Motor Mappings: Implications for Models of Adaptation

NASA Technical Reports Server (NTRS)

Cunningham, H. A.; Welch, Robert B.

1994-01-01

Previous research on adaptation to visual-motor rearrangement suggests that the central nervous system represents accurately only 1 visual-motor mapping at a time. This idea was examined in 3 experiments where subjects tracked a moving target under repeated alternations between 2 initially interfering mappings (the 'normal' mapping characteristic of computer input devices and a 108' rotation of the normal mapping). Alternation between the 2 mappings led to significant reduction in error under the rotated mapping and significant reduction in the adaptation aftereffect ordinarily caused by switching between mappings. Color as a discriminative cue, interference versus decay in adaptation aftereffect, and intermanual transfer were also examined. The results reveal a capacity for multiple concurrent visual-motor mappings, possibly controlled by a parametric process near the motor output stage of processing.

Patterns of Progressive Ganglion Cell-Inner Plexiform Layer Thinning in Glaucoma Detected by OCT.

PubMed

Shin, Joong Won; Sung, Kyung Rim; Park, Sun-Won

2018-04-25

To investigate the spatial characteristics and patterns of progressive macular ganglion cell-inner plexiform layer (GCIPL) thinning in glaucomatous eyes assessed by OCT Guided Progression Analysis (GPA). Longitudinal, retrospective, observational study. Two hundred ninety-two eyes of 192 patients with primary open-angle glaucoma with a mean follow-up of 6.0 years (range, 3.2-8.1 years) were included. Macular GCIPL imaging and visual field (VF) examination were performed at 6-month intervals for 3 years or more. Progressive GCIPL thinning was evaluated by a Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA) GPA device. Spatial characteristics of progressive GCIPL thinning were assessed by the GCIPL thickness change map. The pattern of progressive GCIPL thinning was evaluated by comparing the baseline GCIPL thickness deviation map and the final GCIPL thickness change map. Visual field progression was determined by Early Manifest Glaucoma Trial criteria and linear regression of the VF index. Spatial characteristics and patterns of progressive GCIPL thinning. Seventy-two eyes of 62 participants (24.7% [72/292]) showed progressive GCIPL thinning in the GCIPL thickness change map. Progressive GCIPL thinning was detected most frequently (25.0%) at 2.08 mm from the fovea, and it extended in an arcuate shape in the inferotemporal region (250°-339°). Compared with the baseline GCIPL defects, the progressive GCIPL thinning extended toward the fovea and optic disc. The most common pattern of progressive GCIPL thinning was widening of GCIPL defects (42 eyes [58.3%]), followed by deepening of GCIPL defects (19 eyes [26.4%]) and newly developed GCIPL defects (15 eyes [20.8%]). Visual field progression was accompanied by progressive GCIPL thinning in 41 of 72 eyes (56.9%). Progressive GCIPL thinning preceded (61.0% [25/41]) or occurred concomitantly with (21.9% [9/41]) VF progression. The use of OCT GPA maps offers an effective approach to evaluate the topographic patterns of progressive GCIPL thinning in glaucomatous eyes. Progression of GCIPL thinning occurred before apparent progression on standard automated perimetry in most glaucomatous eyes. Understanding specific patterns and sequences of macular damage may provide important insights in the monitoring of glaucomatous progression. Copyright © 2018 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Statistical wiring of thalamic receptive fields optimizes spatial sampling of the retinal image

PubMed Central

Wang, Xin; Sommer, Friedrich T.; Hirsch, Judith A.

2014-01-01

Summary It is widely assumed that mosaics of retinal ganglion cells establish the optimal representation of visual space. However, relay cells in the visual thalamus often receive convergent input from several retinal afferents and, in cat, outnumber ganglion cells. To explore how the thalamus transforms the retinal image, we built a model of the retinothalamic circuit using experimental data and simple wiring rules. The model shows how the thalamus might form a resampled map of visual space with the potential to facilitate detection of stimulus position in the presence of sensor noise. Bayesian decoding conducted with the model provides support for this scenario. Despite its benefits, however, resampling introduces image blur, thus impairing edge perception. Whole-cell recordings obtained in vivo suggest that this problem is mitigated by arrangements of excitation and inhibition within the receptive field that effectively boost contrast borders, much like strategies used in digital image processing. PMID:24559681

Drowning in Data: Going Beyond Traditional Data Archival to Educate Data Users

NASA Astrophysics Data System (ADS)

Weigel, A. M.; Smith, T.; Smith, D. K.; Bugbee, K.; Sinclair, L.

2017-12-01

Increasing quantities of Earth science data and information prove overwhelming to new and unfamiliar users. Data discovery and use challenges faced by these users are compounded with atmospheric science field campaign data collected by a variety of instruments and stored, visualized, processed and analyzed in different ways. To address data and user needs assessed through annual surveys and user questions, the NASA Global Hydrology Resource Center Distributed Active Archive Center (GHRC DAAC), in collaboration with a graphic designer, has developed a series of resources to help users learn about GHRC science focus areas, field campaigns, instruments, data, and data processing techniques. In this talk, GHRC data recipes, micro articles, interactive data visualization techniques, and artistic science outreach and education efforts, such as ESRI story maps and research as art, will be overviewed. The objective of this talk is to stress the importance artistic information visualization has in communicating with and educating Earth science data users.

Development of Visualizations and Loggable Activities for the Geosciences. Results from Recent TUES Sponsored Projects

NASA Astrophysics Data System (ADS)

De Paor, D. G.; Bailey, J. E.; Whitmeyer, S. J.

2012-12-01

Our TUES research centers on the role of digital data, visualizations, animations, and simulations in undergraduate geoscience education. Digital hardware (smartphones, tablets, GPSs, GigaPan robotic camera mounts, etc.) are revolutionizing field data collection. Software products (GIS, 3-D scanning and modeling programs, virtual globes, etc.) have truly transformed the way geoscientists teach, learn, and do research. Whilst Google-Earth-style visualizations are famously user-friend for the person browsing, they can be notoriously unfriendly for the content creator. Therefore, we developed tools to help educators create and share visualizations as easily as if posting on Facebook. Anyone whoIf you wish to display geological cross sections on Google Earth, go to digitalplanet.org, upload image files, position them on a line of section, and share with the world through our KMZ hosting service. Other tools facilitate screen overlay and 3-D map symbol generation. We advocate use of such technology to enable undergraduate students to 'publish' their first mapping efforts even while they are working in the field. A second outcome of our TUES projects merges Second-Life-style interaction with Google Earth. We created games in which students act as first responders for natural hazard mitigation, prospectors for natural resource explorations, and structural geologist for map-making. Students are represented by avatars and collaborate by exchange of text messages - the natural mode of communication for the current generation. Teachers view logs showing student movements as well as transcripts of text messages and can scaffold student learning and geofence students to prevent wandering. Early results of in-class testing show positive learning outcomes. The third aspect of our program emphasizes dissemination. Experience shows that great effort is required to overcome activation energy and ensure adoption of new technology into the curriculum. We organized a GSA Penrose Conference, a GSA Pardee Keynote Symposium, and AGU Townhall Meeting, and numerous workshops at annual and regional meetings, and set up a web site dedicated to dissemination of program products. Future plans include development of augmented reality teaching resources, hosting of community mapping services, and creation of a truly 4-D virtual globe.;

Primary Visual Cortex as a Saliency Map: A Parameter-Free Prediction and Its Test by Behavioral Data

PubMed Central

Zhaoping, Li; Zhe, Li

2015-01-01

It has been hypothesized that neural activities in the primary visual cortex (V1) represent a saliency map of the visual field to exogenously guide attention. This hypothesis has so far provided only qualitative predictions and their confirmations. We report this hypothesis’ first quantitative prediction, derived without free parameters, and its confirmation by human behavioral data. The hypothesis provides a direct link between V1 neural responses to a visual location and the saliency of that location to guide attention exogenously. In a visual input containing many bars, one of them saliently different from all the other bars which are identical to each other, saliency at the singleton’s location can be measured by the shortness of the reaction time in a visual search for singletons. The hypothesis predicts quantitatively the whole distribution of the reaction times to find a singleton unique in color, orientation, and motion direction from the reaction times to find other types of singletons. The prediction matches human reaction time data. A requirement for this successful prediction is a data-motivated assumption that V1 lacks neurons tuned simultaneously to color, orientation, and motion direction of visual inputs. Since evidence suggests that extrastriate cortices do have such neurons, we discuss the possibility that the extrastriate cortices play no role in guiding exogenous attention so that they can be devoted to other functions like visual decoding and endogenous attention. PMID:26441341

Spherical visual system for real-time virtual reality and surveillance

NASA Astrophysics Data System (ADS)

Chen, Su-Shing

1998-12-01

A spherical visual system has been developed for full field, web-based surveillance, virtual reality, and roundtable video conference. The hardware is a CycloVision parabolic lens mounted on a video camera. The software was developed at the University of Missouri-Columbia. The mathematical model is developed by Su-Shing Chen and Michael Penna in the 1980s. The parabolic image, capturing the full (360 degrees) hemispherical field (except the north pole) of view is transformed into the spherical model of Chen and Penna. In the spherical model, images are invariant under the rotation group and are easily mapped to the image plane tangent to any point on the sphere. The projected image is exactly what the usual camera produces at that angle. Thus a real-time full spherical field video camera is developed by using two pieces of parabolic lenses.

Mapping visual cortex in monkeys and humans using surface-based atlases

NASA Technical Reports Server (NTRS)

Van Essen, D. C.; Lewis, J. W.; Drury, H. A.; Hadjikhani, N.; Tootell, R. B.; Bakircioglu, M.; Miller, M. I.

2001-01-01

We have used surface-based atlases of the cerebral cortex to analyze the functional organization of visual cortex in humans and macaque monkeys. The macaque atlas contains multiple partitioning schemes for visual cortex, including a probabilistic atlas of visual areas derived from a recent architectonic study, plus summary schemes that reflect a combination of physiological and anatomical evidence. The human atlas includes a probabilistic map of eight topographically organized visual areas recently mapped using functional MRI. To facilitate comparisons between species, we used surface-based warping to bring functional and geographic landmarks on the macaque map into register with corresponding landmarks on the human map. The results suggest that extrastriate visual cortex outside the known topographically organized areas is dramatically expanded in human compared to macaque cortex, particularly in the parietal lobe.

The Sounds of Nanoscience: Acoustic STM Analogues

ERIC Educational Resources Information Center

Euler, Manfred

2013-01-01

A hands-on model of scanning tunnelling microscopy (STM) is presented. It uses near-field imaging with sound and computer assisted visualization to create acoustic mappings of resonator arrangements. Due to the (partial) analogy of matter and sound waves the images closely resemble STM scans of atoms. Moreover, the method can be extended to build…

Multi-gradient echo MR thermometry for monitoring of the near-field area during MR-guided high intensity focused ultrasound heating

NASA Astrophysics Data System (ADS)

Lam, Mie K.; de Greef, Martijn; Bouwman, Job G.; Moonen, Chrit T. W.; Viergever, Max A.; Bartels, Lambertus W.

2015-10-01

The multi-gradient echo MR thermometry (MGE MRT) method is proposed to use at the interface of the muscle and fat layers found in the abdominal wall, to monitor MR-HIFU heating. As MGE MRT uses fat as a reference, it is field-drift corrected. Relative temperature maps were reconstructed by subtracting absolute temperature maps. Because the absolute temperature maps are reconstructed of individual scans, MGE MRT provides the flexibility of interleaved mapping of temperature changes between two arbitrary time points. The method’s performance was assessed in an ex vivo water bath experiment. An ex vivo HIFU experiment was performed to show the method’s ability to monitor heating of consecutive HIFU sonications and to estimate cooling time constants, in the presence of field drift. The interleaved use between scans of a clinical protocol was demonstrated in vivo in a patient during a clinical uterine fibroid treatment. The relative temperature measurements were accurate (mean absolute error 0.3 °C) and provided excellent visualization of the heating of consecutive HIFU sonications. Maps were reconstructed of estimated cooling time constants and mean ROI values could be well explained by the applied heating pattern. Heating upon HIFU sonication and subsequent cooling could be observed in the in vivo demonstration.

Jupiter's Temperatures--Broad Latitude

NASA Technical Reports Server (NTRS)

1997-01-01

This is one of the highest resolution images ever recorded of Jupiter's temperature field. It was obtained by NASA's Galileo mission, with its Photopolarimeter-Radiometer (PPR) experiment, during the seventh of its 10 orbits around Jupiter to date. This map, shown in the left panel, indicates the forces powering Jovian winds, and differentiates between areas of strongest upwelling and downwelling winds in the upper part of the atmosphere. A Hubble Space Telescope Planetary Camera color composite of this same region, taken within 10 hours of the PPR map, is shown in the right panel for the same region, as a reference to the visual clouds. An outline of the region mapped by the PPR is also shown.

This atmospheric observation covered a broad latitude region, and it shows that the visually dark regions generally have warmer temperatures than the visually light ones, indicating that they are regions of downwelling, dry air which clear out cloud condensate particles. The 'little red spot' at the northernmost part of this image is colder than its surroundings, consistent with it being a region of upwelling and cooling gas. The smaller spots to its southeast (lower right) and other lighter spots in the HST image are all colder than their surroundings, consistent with regions of upwelling and cooling gas. The northern half of the brightest band in the map is brighter than the southern half, and it reveals some detailed structure, down to the 1900- kilometer (1200-mile) resolution of the PPR, which is not always readily correlated with variations of the visual cloud field.

One surprise of this temperature map involved temperatures near the dark blue-gray feature in the map, an area like the one into which the Probe descended. While large regions of downwelling wind heat the local area elsewhere in Jupiter, this region of vigorous downwelling appears close to being thermally neutral. The drying, downwelling winds may be deeper in the atmosphere than sensed by the PPR, or this region may have enough downwelling motions so that additional downwelling has little effect on energy and temperature. Either scenario indicates these generally clear and dry regions are fundamentally different from most of Jupiter's downwelling regions.

The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov.

Visualizing Earth's Erupting Volcanoes and Wildfires: Seven Years of Data From the Earth Observing Mission

NASA Astrophysics Data System (ADS)

Wright, R.; Pilger, E.; Flynn, L. P.; Harris, A. J.

2006-12-01

Volcanic eruptions and wildfires are natural hazards that are truly global in their geographic scope, as well as being temporally very dynamic. As such, satellite remote sensing lends itself to their effective detection and monitoring. The results of such mapping can be communicated in the form of traditional static maps. However, most hazards have strong time-dependent forcing mechanisms (in the case of biomass burning, climate) and the dynamism of these geophysical phenomena requires a suitable method for their presentation. Here, we present visualizations of the amount of thermal energy radiated by all of Earth's sub-aerially erupting volcanoes, wildfires and industrial heat sources over a seven year period. These visualizations condense the results obtained from the near-real-time analysis of over 1.2 million MODIS (Moderate Resolution Imaging Spectro-radiometer) images, acquired from NASA's Terra and Aqua platforms. In the accompanying poster we will describe a) the raw data, b) how these data can be used to derive higher-order geophysical parameters, and c) how the visualization of these derived products adds scientific value to the raw data. The visualizations reveal spatio-temporal trends in fire radiated energy (and by proxy, biomass combustion rates and carbon emissions into the atmosphere), which are indiscernible in the static data set. Most notable are differences in biomass combustion between the North American and Eurasian Boreal forests. We also give examples relating to the development of lava flow-fields at Mount Etna (Italy) and Kilauea (USA), as well as variations in heat output from Iraqi oil fields, that span the onset of the 2003 Persian Gulf War. The raw data used to generate these visualizations are routinely made available via the Internet, as portable ASCII files. They can therefore be easily integrated with image datasets, by other researchers, to create their own visualizations.

Geologic mapping on the deep seafloor: Reconstructing lava flow emplacement and eruptive history at the Galápagos Spreading Center

NASA Astrophysics Data System (ADS)

McClinton, J. T.; White, S.; Colman, A.; Sinton, J. M.; Bowles, J. A.

2012-12-01

The deep seafloor imposes significant difficulties on data collection that require the integration of multiple data sets and the implementation of unconventional geologic mapping techniques. We combine visual mapping of geological contacts by submersible with lava flow morphology maps and relative and absolute age constraints to create a spatiotemporal framework for examining submarine lava flow emplacement at the intermediate-spreading, hotspot-affected Galápagos Spreading Center (GSC). We mapped 18 lava flow fields, interpreted to be separate eruptive episodes, within two study areas at the GSC using visual observations of superposition, surface preservation and sediment cover from submersible and towed camera surveys, augmented by high-resolution sonar surveys and sample petrology [Colman et al., Effects of variable magma supply on mid-ocean ridge eruptions: Constraints from mapped lava flow fields along the Galápagos Spreading Center; 2012 G3]. We also mapped the lava flow morphology within the majority of these eruptive units using an automated, machine-learning classification method [McClinton et al., Neuro-fuzzy classification of submarine lava flow morphology; 2012 PE&RS]. The method combines detailed geometric, acoustic, and textural attributes derived from high-resolution sonar data with visual observations and a machine-learning algorithm to classify submarine lava flow morphology as pillows, lobates, or sheets. The resulting lava morphology maps are a valuable tool for interpreting patterns in the emplacement of submarine lava flows at a mid-ocean ridge (MOR). Within our study area at 92°W, where the GSC has a relatively high magma supply, high effusion rate sheet and lobate lavas are more abundant in the oldest mapped eruptive units, while the most recent eruptions mostly consist of low effusion rate pillow lavas. The older eruptions (roughly 400yrs BP by paleomagnetic intensity) extend up to 1km off axis via prominent channels and tubes, while the most recent eruptions (<100yrs BP by paleomagnetic intensity) are mainly on-axis pillow ridges and domes. These spatial and temporal trends suggest a gradual transition from low-relief, "paving" eruptions to relief-building, "constructional" eruptions. In our second study area at 95°W, where magma supply is lower, eruptions mostly consist of axial seamounts and irregularly shaped clusters of pillow mounds. Many have summit plateaus with inflated, partially collapsed lobate lavas suggesting variable effusion rates and topographic influence on lava flows. In addition, a relatively extensive (~9.5km2) flow field of inflated lobate and sheet lavas erupted from vents ~1km north of the ridge axis and flowed ~1km into the inner axial graben through channels and tubes, ponding against older structures and leaving prominent "bathtub rings" and collapse features. This eruption provides direct evidence that large, high effusion rate eruptions can occur in low magma supply settings at MORs.

Using perceptual rules in interactive visualization

NASA Astrophysics Data System (ADS)

Rogowitz, Bernice E.; Treinish, Lloyd A.

1994-05-01

In visualization, data are represented as variations in grayscale, hue, shape, and texture. They can be mapped to lines, surfaces, and glyphs, and can be represented statically or in animation. In modem visualization systems, the choices for representing data seem unlimited. This is both a blessing and a curse, however, since the visual impression created by the visualization depends critically on which dimensions are selected for representing the data (Bertin, 1967; Tufte, 1983; Cleveland, 1991). In modem visualization systems, the user can interactively select many different mapping and representation operations, and can interactively select processing operations (e.g., applying a color map), realization operations (e.g., generating geometric structures such as contours or streamlines), and rendering operations (e.g., shading or ray-tracing). The user can, for example, map data to a color map, then apply contour lines, then shift the viewing angle, then change the color map again, etc. In many systems, the user can vary the choices for each operation, selecting, for example, particular color maps, contour characteristics, and shading techniques. The hope is that this process will eventually converge on a visual representation which expresses the structure of the data and effectively communicates its message in a way that meets the user's goals. Sometimes, however, it results in visual representations which are confusing, misleading, and garish.

Assessing species distribution using Google Street View: a pilot study with the Pine Processionary Moth.

PubMed

Rousselet, Jérôme; Imbert, Charles-Edouard; Dekri, Anissa; Garcia, Jacques; Goussard, Francis; Vincent, Bruno; Denux, Olivier; Robinet, Christelle; Dorkeld, Franck; Roques, Alain; Rossi, Jean-Pierre

2013-01-01

Mapping species spatial distribution using spatial inference and prediction requires a lot of data. Occurrence data are generally not easily available from the literature and are very time-consuming to collect in the field. For that reason, we designed a survey to explore to which extent large-scale databases such as Google maps and Google Street View could be used to derive valid occurrence data. We worked with the Pine Processionary Moth (PPM) Thaumetopoea pityocampa because the larvae of that moth build silk nests that are easily visible. The presence of the species at one location can therefore be inferred from visual records derived from the panoramic views available from Google Street View. We designed a standardized procedure allowing evaluating the presence of the PPM on a sampling grid covering the landscape under study. The outputs were compared to field data. We investigated two landscapes using grids of different extent and mesh size. Data derived from Google Street View were highly similar to field data in the large-scale analysis based on a square grid with a mesh of 16 km (96% of matching records). Using a 2 km mesh size led to a strong divergence between field and Google-derived data (46% of matching records). We conclude that Google database might provide useful occurrence data for mapping the distribution of species which presence can be visually evaluated such as the PPM. However, the accuracy of the output strongly depends on the spatial scales considered and on the sampling grid used. Other factors such as the coverage of Google Street View network with regards to sampling grid size and the spatial distribution of host trees with regards to road network may also be determinant.

Assessing Species Distribution Using Google Street View: A Pilot Study with the Pine Processionary Moth

PubMed Central

Dekri, Anissa; Garcia, Jacques; Goussard, Francis; Vincent, Bruno; Denux, Olivier; Robinet, Christelle; Dorkeld, Franck; Roques, Alain; Rossi, Jean-Pierre

2013-01-01

Mapping species spatial distribution using spatial inference and prediction requires a lot of data. Occurrence data are generally not easily available from the literature and are very time-consuming to collect in the field. For that reason, we designed a survey to explore to which extent large-scale databases such as Google maps and Google street view could be used to derive valid occurrence data. We worked with the Pine Processionary Moth (PPM) Thaumetopoea pityocampa because the larvae of that moth build silk nests that are easily visible. The presence of the species at one location can therefore be inferred from visual records derived from the panoramic views available from Google street view. We designed a standardized procedure allowing evaluating the presence of the PPM on a sampling grid covering the landscape under study. The outputs were compared to field data. We investigated two landscapes using grids of different extent and mesh size. Data derived from Google street view were highly similar to field data in the large-scale analysis based on a square grid with a mesh of 16 km (96% of matching records). Using a 2 km mesh size led to a strong divergence between field and Google-derived data (46% of matching records). We conclude that Google database might provide useful occurrence data for mapping the distribution of species which presence can be visually evaluated such as the PPM. However, the accuracy of the output strongly depends on the spatial scales considered and on the sampling grid used. Other factors such as the coverage of Google street view network with regards to sampling grid size and the spatial distribution of host trees with regards to road network may also be determinant. PMID:24130675

Atlas of Cancer Signalling Network: a systems biology resource for integrative analysis of cancer data with Google Maps

PubMed Central

Kuperstein, I; Bonnet, E; Nguyen, H-A; Cohen, D; Viara, E; Grieco, L; Fourquet, S; Calzone, L; Russo, C; Kondratova, M; Dutreix, M; Barillot, E; Zinovyev, A

2015-01-01

Cancerogenesis is driven by mutations leading to aberrant functioning of a complex network of molecular interactions and simultaneously affecting multiple cellular functions. Therefore, the successful application of bioinformatics and systems biology methods for analysis of high-throughput data in cancer research heavily depends on availability of global and detailed reconstructions of signalling networks amenable for computational analysis. We present here the Atlas of Cancer Signalling Network (ACSN), an interactive and comprehensive map of molecular mechanisms implicated in cancer. The resource includes tools for map navigation, visualization and analysis of molecular data in the context of signalling network maps. Constructing and updating ACSN involves careful manual curation of molecular biology literature and participation of experts in the corresponding fields. The cancer-oriented content of ACSN is completely original and covers major mechanisms involved in cancer progression, including DNA repair, cell survival, apoptosis, cell cycle, EMT and cell motility. Cell signalling mechanisms are depicted in detail, together creating a seamless ‘geographic-like' map of molecular interactions frequently deregulated in cancer. The map is browsable using NaviCell web interface using the Google Maps engine and semantic zooming principle. The associated web-blog provides a forum for commenting and curating the ACSN content. ACSN allows uploading heterogeneous omics data from users on top of the maps for visualization and performing functional analyses. We suggest several scenarios for ACSN application in cancer research, particularly for visualizing high-throughput data, starting from small interfering RNA-based screening results or mutation frequencies to innovative ways of exploring transcriptomes and phosphoproteomes. Integration and analysis of these data in the context of ACSN may help interpret their biological significance and formulate mechanistic hypotheses. ACSN may also support patient stratification, prediction of treatment response and resistance to cancer drugs, as well as design of novel treatment strategies. PMID:26192618

Data Flow Analysis and Visualization for Spatiotemporal Statistical Data without Trajectory Information.

PubMed

Kim, Seokyeon; Jeong, Seongmin; Woo, Insoo; Jang, Yun; Maciejewski, Ross; Ebert, David S

2018-03-01

Geographic visualization research has focused on a variety of techniques to represent and explore spatiotemporal data. The goal of those techniques is to enable users to explore events and interactions over space and time in order to facilitate the discovery of patterns, anomalies and relationships within the data. However, it is difficult to extract and visualize data flow patterns over time for non-directional statistical data without trajectory information. In this work, we develop a novel flow analysis technique to extract, represent, and analyze flow maps of non-directional spatiotemporal data unaccompanied by trajectory information. We estimate a continuous distribution of these events over space and time, and extract flow fields for spatial and temporal changes utilizing a gravity model. Then, we visualize the spatiotemporal patterns in the data by employing flow visualization techniques. The user is presented with temporal trends of geo-referenced discrete events on a map. As such, overall spatiotemporal data flow patterns help users analyze geo-referenced temporal events, such as disease outbreaks, crime patterns, etc. To validate our model, we discard the trajectory information in an origin-destination dataset and apply our technique to the data and compare the derived trajectories and the original. Finally, we present spatiotemporal trend analysis for statistical datasets including twitter data, maritime search and rescue events, and syndromic surveillance.

Overview of long-term field experiments in Germany - metadata visualization

NASA Astrophysics Data System (ADS)

Muqit Zoarder, Md Abdul; Heinrich, Uwe; Svoboda, Nikolai; Grosse, Meike; Hierold, Wilfried

2017-04-01

BonaRes ("soil as a sustainable resource for the bioeconomy") is conducting to collect data and metadata of agricultural long-term field experiments (LTFE) of Germany. It is funded by the German Federal Ministry of Education and Research (BMBF) under the umbrella of the National Research Strategy BioEconomy 2030. BonaRes consists of ten interdisciplinary research project consortia and the 'BonaRes - Centre for Soil Research'. BonaRes Data Centre is responsible for collecting all LTFE data and regarding metadata into an enterprise database upon higher level of security and visualization of the data and metadata through data portal. In the frame of the BonaRes project, we are compiling an overview of long-term field experiments in Germany that is based on a literature review, the results of the online survey and direct contacts with LTFE operators. Information about research topic, contact person, website, experiment setup and analyzed parameters are collected. Based on the collected LTFE data, an enterprise geodatabase is developed and a GIS-based web-information system about LTFE in Germany is also settled. Various aspects of the LTFE, like experiment type, land-use type, agricultural category and duration of experiment, are presented in thematic maps. This information system is dynamically linked to the database, which means changes in the data directly affect the presentation. An easy data searching option using LTFE name, -location or -operators and the dynamic layer selection ensure a user-friendly web application. Dispersion and visualization of the overlapping LTFE points on the overview map are also challenging and we make it automatized at very zoom level which is also a consistent part of this application. The application provides both, spatial location and meta-information of LTFEs, which is backed-up by an enterprise geodatabase, GIS server for hosting map services and Java script API for web application development.

Visualizing water

NASA Astrophysics Data System (ADS)

Baart, F.; van Gils, A.; Hagenaars, G.; Donchyts, G.; Eisemann, E.; van Velzen, J. W.

2016-12-01

A compelling visualization is captivating, beautiful and narrative. Here we show how melding the skills of computer graphics, art, statistics, and environmental modeling can be used to generate innovative, attractive and very informative visualizations. We focus on the topic of visualizing forecasts and measurements of water (water level, waves, currents, density, and salinity). For the field of computer graphics and arts, water is an important topic because it occurs in many natural scenes. For environmental modeling and statistics, water is an important topic because the water is essential for transport, a healthy environment, fruitful agriculture, and a safe environment.The different disciplines take different approaches to visualizing water. In computer graphics, one focusses on creating water as realistic looking as possible. The focus on realistic perception (versus the focus on the physical balance pursued by environmental scientists) resulted in fascinating renderings, as seen in recent games and movies. Visualization techniques for statistical results have benefited from the advancement in design and journalism, resulting in enthralling infographics. The field of environmental modeling has absorbed advances in contemporary cartography as seen in the latest interactive data-driven maps. We systematically review the design emerging types of water visualizations. The examples that we analyze range from dynamically animated forecasts, interactive paintings, infographics, modern cartography to web-based photorealistic rendering. By characterizing the intended audience, the design choices, the scales (e.g. time, space), and the explorability we provide a set of guidelines and genres. The unique contributions of the different fields show how the innovations in the current state of the art of water visualization have benefited from inter-disciplinary collaborations.

Synchronization Design and Error Analysis of Near-Infrared Cameras in Surgical Navigation.

PubMed

Cai, Ken; Yang, Rongqian; Chen, Huazhou; Huang, Yizhou; Wen, Xiaoyan; Huang, Wenhua; Ou, Shanxing

2016-01-01

The accuracy of optical tracking systems is important to scientists. With the improvements reported in this regard, such systems have been applied to an increasing number of operations. To enhance the accuracy of these systems further and to reduce the effect of synchronization and visual field errors, this study introduces a field-programmable gate array (FPGA)-based synchronization control method, a method for measuring synchronous errors, and an error distribution map in field of view. Synchronization control maximizes the parallel processing capability of FPGA, and synchronous error measurement can effectively detect the errors caused by synchronization in an optical tracking system. The distribution of positioning errors can be detected in field of view through the aforementioned error distribution map. Therefore, doctors can perform surgeries in areas with few positioning errors, and the accuracy of optical tracking systems is considerably improved. The system is analyzed and validated in this study through experiments that involve the proposed methods, which can eliminate positioning errors attributed to asynchronous cameras and different fields of view.

Semantic layers for illustrative volume rendering.

PubMed

Rautek, Peter; Bruckner, Stefan; Gröller, Eduard

2007-01-01

Direct volume rendering techniques map volumetric attributes (e.g., density, gradient magnitude, etc.) to visual styles. Commonly this mapping is specified by a transfer function. The specification of transfer functions is a complex task and requires expert knowledge about the underlying rendering technique. In the case of multiple volumetric attributes and multiple visual styles the specification of the multi-dimensional transfer function becomes more challenging and non-intuitive. We present a novel methodology for the specification of a mapping from several volumetric attributes to multiple illustrative visual styles. We introduce semantic layers that allow a domain expert to specify the mapping in the natural language of the domain. A semantic layer defines the mapping of volumetric attributes to one visual style. Volumetric attributes and visual styles are represented as fuzzy sets. The mapping is specified by rules that are evaluated with fuzzy logic arithmetics. The user specifies the fuzzy sets and the rules without special knowledge about the underlying rendering technique. Semantic layers allow for a linguistic specification of the mapping from attributes to visual styles replacing the traditional transfer function specification.

Evaluation of a Method for Estimating Retinal Ganglion Cell Counts Using Visual Fields and Optical Coherence Tomography

PubMed Central

Raza, Ali S.; Hood, Donald C.

2015-01-01

Purpose. To evaluate the accuracy and generalizability of a published model that derives estimates of retinal ganglion cell (RGC) counts and relates structural and functional changes due to glaucoma. Methods. Both the Harwerth et al. nonlinear model (H-NLM) and the Hood and Kardon linear model (HK-LM) were applied to an independent dataset of frequency-domain optical coherence tomography and visual fields, consisting of 48 eyes of 48 healthy controls, 100 eyes of 77 glaucoma patients and suspects, and 18 eyes of 14 nonarteritic anterior ischemic optic neuropathy (ION) patients with severe vision loss. Using the coefficient of determination R2, the models were compared while keeping constant the topographic maps, specifically a map by Garway-Heath et al. and a separate map by Harwerth et al., which relate sensitivity test stimulus locations to corresponding regions around the optic disc. Additionally, simulations were used to evaluate the assumptions of the H-NLM. Results. Although the predictions of the HK-LM with the anatomically-derived Garway-Heath et al. map were reasonably good (R2 = 0.31–0.64), the predictions of the H-NLM were poor (R2 < 0) regardless of the map used. Furthermore, simulations of the H-NLM yielded results that differed substantially from RGC estimates based on histology from human subjects. Finally, the value-added of factors increasing the relative complexity of the H-NLM, such as assumptions regarding age- and stage-dependent corrections to structural measures, was unclear. Conclusions. Several of the assumptions underlying the H-NLM should be revisited. Studies and models relying on the RGC estimates of the H-NLM should be interpreted with caution. PMID:25604684

Applications of magnetic resonance image segmentation in neurology

NASA Astrophysics Data System (ADS)

Heinonen, Tomi; Lahtinen, Antti J.; Dastidar, Prasun; Ryymin, Pertti; Laarne, Paeivi; Malmivuo, Jaakko; Laasonen, Erkki; Frey, Harry; Eskola, Hannu

1999-05-01

After the introduction of digital imagin devices in medicine computerized tissue recognition and classification have become important in research and clinical applications. Segmented data can be applied among numerous research fields including volumetric analysis of particular tissues and structures, construction of anatomical modes, 3D visualization, and multimodal visualization, hence making segmentation essential in modern image analysis. In this research project several PC based software were developed in order to segment medical images, to visualize raw and segmented images in 3D, and to produce EEG brain maps in which MR images and EEG signals were integrated. The software package was tested and validated in numerous clinical research projects in hospital environment.

Revisiting flow maps: a classification and a 3D alternative to visual clutter

NASA Astrophysics Data System (ADS)

Gu, Yuhang; Kraak, Menno-Jan; Engelhardt, Yuri

2018-05-01

Flow maps have long been servicing people in exploring movement by representing origin-destination data (OD data). Due to recent developments in data collecting techniques the amount of movement data is increasing dramatically. With such huge amounts of data, visual clutter in flow maps is becoming a challenge. This paper revisits flow maps, provides an overview of the characteristics of OD data and proposes a classification system for flow maps. For dealing with problems of visual clutter, 3D flow maps are proposed as potential alternative to 2D flow maps.

Visual geography

USGS Publications Warehouse

,; ,; ,

1991-01-01

Maps are, among other things, a way of making geography visual. They are world views, ways of thinking, and ways of communicating. They depict our world and guide us through it. Visual Geography probes the essence of maps and mapmaking. It follows the story of cartography through the millennia, across the globe, and beyond the solar system. It includes some of the world's most beautiful and enduring maps, some of its most historic - a map in Columbus' hand, the map that was carried to the Moon, the first map to show America - and it examines the urge to map, to measure our world, and to record it graphically.

Accessible maps for the color vision deficient observers: past and present knowledge and future possibilities

NASA Astrophysics Data System (ADS)

Kvitle, Anne Kristin

2018-05-01

Color is part of the visual variables in map, serving an aesthetic part and as a guide of attention. Impaired color vision affects the ability to distinguish colors, which makes the task of decoding the map colors difficult. Map reading is reported as a challenging task for these observers, especially when the size of stimuli is small. The aim of this study is to review existing methods for map design for color vision deficient users. A systematic review of research literature and case studies of map design for CVD observers has been conducted in order to give an overview of current knowledge and future research challenges. In addition, relevant research on simulations of CVD and color image enhancement for these observers from other fields of industry is included. The study identified two main approaches: pre-processing by using accessible colors and post-processing by using enhancement methods. Some of the methods may be applied for maps, but requires tailoring of test images according to map types.

The Retinotopic Organization of Macaque Occipitotemporal Cortex Anterior to V4 and Caudoventral to the Middle Temporal (MT) Cluster

PubMed Central

Janssens, Thomas; Orban, Guy A.

2014-01-01

The retinotopic organization of macaque occipitotemporal cortex rostral to area V4 and caudorostral to the recently described middle temporal (MT) cluster of the monkey (Kolster et al., 2009) is not well established. The proposed number of areas within this region varies from one to four, underscoring the ambiguity concerning the functional organization in this region of extrastriate cortex. We used phase-encoded retinotopic functional MRI mapping methods to reveal the functional topography of this cortical domain. Polar-angle maps showed one complete hemifield representation bordering area V4 anteriorly, split into dorsal and ventral counterparts corresponding to the lower and upper visual field quadrants, respectively. The location of this hemifield representation corresponds to area V4A. More rostroventrally, we identified three other complete hemifield representations. Two of these correspond to the dorsal and the ventral posterior inferotemporal areas (PITd and PITv, respectively) as identified in the Felleman and Van Essen (1991) scheme. The third representation has been tentatively named dorsal occipitotemporal area (OTd). Areas V4A, PITd, PITv, and OTd share a central visual field representation, similar to the areas constituting the MT cluster. Furthermore, they vary widely in size and represent the complete contralateral visual field. Functionally, these four areas show little motion sensitivity, unlike those of the MT cluster, and two of them, OTd and PITd, displayed pronounced two-dimensional shape sensitivity. In general, these results suggest that retinotopically organized tissue extends farther into rostral occipitotemporal cortex of the monkey than generally assumed. PMID:25080580

Identification of cardiac rhythm features by mathematical analysis of vector fields.

PubMed

Fitzgerald, Tamara N; Brooks, Dana H; Triedman, John K

2005-01-01

Automated techniques for locating cardiac arrhythmia features are limited, and cardiologists generally rely on isochronal maps to infer patterns in the cardiac activation sequence during an ablation procedure. Velocity vector mapping has been proposed as an alternative method to study cardiac activation in both clinical and research environments. In addition to the visual cues that vector maps can provide, vector fields can be analyzed using mathematical operators such as the divergence and curl. In the current study, conduction features were extracted from velocity vector fields computed from cardiac mapping data. The divergence was used to locate ectopic foci and wavefront collisions, and the curl to identify central obstacles in reentrant circuits. Both operators were applied to simulated rhythms created from a two-dimensional cellular automaton model, to measured data from an in situ experimental canine model, and to complex three-dimensional human cardiac mapping data sets. Analysis of simulated vector fields indicated that the divergence is useful in identifying ectopic foci, with a relatively small number of vectors and with errors of up to 30 degrees in the angle measurements. The curl was useful for identifying central obstacles in reentrant circuits, and the number of velocity vectors needed increased as the rhythm became more complex. The divergence was able to accurately identify canine in situ pacing sites, areas of breakthrough activation, and wavefront collisions. In data from human arrhythmias, the divergence reliably estimated origins of electrical activity and wavefront collisions, but the curl was less reliable at locating central obstacles in reentrant circuits, possibly due to the retrospective nature of data collection. The results indicate that the curl and divergence operators applied to velocity vector maps have the potential to add valuable information in cardiac mapping and can be used to supplement human pattern recognition.

A survey of simultaneous localization and mapping on unstructured lunar complex environment

NASA Astrophysics Data System (ADS)

Wang, Yiqiao; Zhang, Wei; An, Pei

2017-10-01

Simultaneous localization and mapping (SLAM) technology is the key to realizing lunar rover's intelligent perception and autonomous navigation. It embodies the autonomous ability of mobile robot, and has attracted plenty of concerns of researchers in the past thirty years. Visual sensors are meaningful to SLAM research because they can provide a wealth of information. Visual SLAM uses merely images as external information to estimate the location of the robot and construct the environment map. Nowadays, SLAM technology still has problems when applied in large-scale, unstructured and complex environment. Based on the latest technology in the field of visual SLAM, this paper investigates and summarizes the SLAM technology using in the unstructured complex environment of lunar surface. In particular, we focus on summarizing and comparing the detection and matching of features of SIFT, SURF and ORB, in the meanwhile discussing their advantages and disadvantages. We have analyzed the three main methods: SLAM Based on Extended Kalman Filter, SLAM Based on Particle Filter and SLAM Based on Graph Optimization (EKF-SLAM, PF-SLAM and Graph-based SLAM). Finally, this article summarizes and discusses the key scientific and technical difficulties in the lunar context that Visual SLAM faces. At the same time, we have explored the frontier issues such as multi-sensor fusion SLAM and multi-robot cooperative SLAM technology. We also predict and prospect the development trend of lunar rover SLAM technology, and put forward some ideas of further research.

Implementing automatic LiDAR and supervised mapping methodologies to quantify agricultural terraced landforms at landscape scale: the case of Veneto Region

NASA Astrophysics Data System (ADS)

Eugenio Pappalardo, Salvatore; Ferrarese, Francesco; Tarolli, Paolo; Varotto, Mauro

2016-04-01

Traditional agricultural terraced landscapes presently embody an important cultural value to be deeply investigated, both for their role in local heritage and cultural economy and for their potential geo-hydrological hazard due to abandonment and degradation. Moreover, traditional terraced landscapes are usually based on non-intensive agro-systems and may enhance some important ecosystems services such as agro-biodiversity conservation and cultural services. Due to their unplanned genesis, mapping, quantifying and classifying agricultural terraces at regional scale is often critical as far as they are usually set up on geomorphologically and historically complex landscapes. Hence, traditional mapping methods are generally based on scientific literature and local documentation, historical and cadastral sources, technical cartography and aerial images visual interpretation or, finally, field surveys. By this, limitations and uncertainty in mapping at regional scale are basically related to forest cover and lack in thematic cartography. The Veneto Region (NE of Italy) presents a wide heterogeneity of agricultural terraced landscapes, mainly distributed within the hilly and Prealps areas. Previous studies performed by traditional mapping method quantified 2,688 ha of terraced areas, showing the higher values within the Prealps of Lessinia (1,013 ha, within the Province of Verona) and in the Brenta Valley (421 ha, within the Province of Vicenza); however, terraced features of these case studies show relevant differences in terms of fragmentation and intensity of terraces, highlighting dissimilar degrees of clusterization: 1.7 ha on one hand (Province of Verona) and 1.2 ha per terraced area (Province of Vicenza) on the other one. The aim of this paper is to implement and to compare automatic methodologies with traditional survey methodologies to map and assess agricultural terraces in two representative areas of the Veneto Region. Testing different Remote Sensing analyses such as LiDAR topography survey and visual interpretation from aerial orthophotos (RGB+NIR bands) we performed a territorial analysis in the Lessinia and Brenta Valley case studies. Preliminary results show that terraced feature extraction by automatic LiDAR survey is more efficient both in identifying geometries (walls and terraced surfaces) and in quantifying features under the forest canopy; however, traditional mapping methodology confirms its strength by matching different methods and different data such as aerial photo, visual interpretation, maps and field surveys. Hence, the two methods here compared represent a cross-validation and let us to better know the complexity of this kind of landscape.

A functional hierarchy within the parietofrontal network in stimulus selection and attention control.

PubMed

Ibos, Guilhem; Duhamel, Jean-René; Ben Hamed, Suliann

2013-05-08

Although we are confronted with an ever-changing environment, we do not have the capacity to analyze all incoming sensory information. Perception is selective and is guided both by salient events occurring in our visual field and by cognitive premises about what needs our attention. Although the lateral intraparietal area (LIP) and frontal eye field (FEF) are known to represent the position of visual attention, their respective contributions to its control are still unclear. Here, we report LIP and FEF neuronal activities recorded while monkeys performed a voluntary attention-orientation target-detection task. We show that both encode behaviorally significant events, but that the FEF plays a specific role in mapping abstract cue instructions onto a spatial priority map to voluntarily guide attention. On the basis of a latency analysis, we show that the coding of stimulus identity and position precedes the emergence of an explicit attentional signal within the FEF. We also describe dynamic temporal hierarchies between LIP and FEF: stimuli carrying the highest intrinsic saliency are signaled by LIP before FEF, whereas stimuli carrying the highest extrinsic saliency are signaled in FEF before LIP. This suggests that whereas the parietofrontal attentional network most probably processes visual information in a recurrent way, exogenous processing predominates in the parietal cortex and the endogenous control of attention takes place in the FEF.

The Pattern of Visual Fixation Eccentricity and Instability in Optic Neuropathy and Its Spatial Relationship to Retinal Ganglion Cell Layer Thickness.

PubMed

Mallery, Robert M; Poolman, Pieter; Thurtell, Matthew J; Wang, Jui-Kai; Garvin, Mona K; Ledolter, Johannes; Kardon, Randy H

2016-07-01

The purpose of this study was to assess whether clinically useful measures of fixation instability and eccentricity can be derived from retinal tracking data obtained during optical coherence tomography (OCT) in patients with optic neuropathy (ON) and to develop a method for relating fixation to the retinal ganglion cell complex (GCC) thickness. Twenty-nine patients with ON underwent macular volume OCT with 30 seconds of confocal scanning laser ophthalmoscope (cSLO)-based eye tracking during fixation. Kernel density estimation quantified fixation instability and fixation eccentricity from the distribution of fixation points on the retina. Preferred ganglion cell layer loci (PGCL) and their relationship to the GCC thickness map were derived, accounting for radial displacement of retinal ganglion cell soma from their corresponding cones. Fixation instability was increased in ON eyes (0.21 deg2) compared with normal eyes (0.06982 deg2; P < 0.001), and fixation eccentricity was increased in ON eyes (0.48°) compared with normal eyes (0.24°; P = 0.03). Fixation instability and eccentricity each correlated moderately with logMAR acuity and were highly predictive of central visual field loss. Twenty-six of 35 ON eyes had PGCL skewed toward local maxima of the GCC thickness map. Patients with bilateral dense central scotomas had PGCL in homonymous retinal locations with respect to the fovea. Fixation instability and eccentricity measures obtained during cSLO-OCT assess the function of perifoveal retinal elements and predict central visual field loss in patients with ON. A model relating fixation to the GCC thickness map offers a method to assess the structure-function relationship between fixation and areas of preserved GCC in patients with ON.

The Pattern of Visual Fixation Eccentricity and Instability in Optic Neuropathy and Its Spatial Relationship to Retinal Ganglion Cell Layer Thickness

PubMed Central

M. Mallery, Robert; Poolman, Pieter; J. Thurtell, Matthew; Wang, Jui-Kai; K. Garvin, Mona; Ledolter, Johannes; Kardon, Randy H.

2016-01-01

Purpose The purpose of this study was to assess whether clinically useful measures of fixation instability and eccentricity can be derived from retinal tracking data obtained during optical coherence tomography (OCT) in patients with optic neuropathy (ON) and to develop a method for relating fixation to the retinal ganglion cell complex (GCC) thickness. Methods Twenty-nine patients with ON underwent macular volume OCT with 30 seconds of confocal scanning laser ophthalmoscope (cSLO)-based eye tracking during fixation. Kernel density estimation quantified fixation instability and fixation eccentricity from the distribution of fixation points on the retina. Preferred ganglion cell layer loci (PGCL) and their relationship to the GCC thickness map were derived, accounting for radial displacement of retinal ganglion cell soma from their corresponding cones. Results Fixation instability was increased in ON eyes (0.21 deg2) compared with normal eyes (0.06982 deg2; P < 0.001), and fixation eccentricity was increased in ON eyes (0.48°) compared with normal eyes (0.24°; P = 0.03). Fixation instability and eccentricity each correlated moderately with logMAR acuity and were highly predictive of central visual field loss. Twenty-six of 35 ON eyes had PGCL skewed toward local maxima of the GCC thickness map. Patients with bilateral dense central scotomas had PGCL in homonymous retinal locations with respect to the fovea. Conclusions Fixation instability and eccentricity measures obtained during cSLO-OCT assess the function of perifoveal retinal elements and predict central visual field loss in patients with ON. A model relating fixation to the GCC thickness map offers a method to assess the structure–function relationship between fixation and areas of preserved GCC in patients with ON. PMID:27409502

Receptive-field subfields of V2 neurons in macaque monkeys are adult-like near birth.

PubMed

Zhang, Bin; Tao, Xiaofeng; Shen, Guofu; Smith, Earl L; Ohzawa, Izumi; Chino, Yuzo M

2013-02-06

Infant primates can discriminate texture-defined form despite their relatively low visual acuity. The neuronal mechanisms underlying this remarkable visual capacity of infants have not been studied in nonhuman primates. Since many V2 neurons in adult monkeys can extract the local features in complex stimuli that are required for form vision, we used two-dimensional dynamic noise stimuli and local spectral reverse correlation to measure whether the spatial map of receptive-field subfields in individual V2 neurons is sufficiently mature near birth to capture local features. As in adults, most V2 neurons in 4-week-old monkeys showed a relatively high degree of homogeneity in the spatial matrix of facilitatory subfields. However, ∼25% of V2 neurons had the subfield map where the neighboring facilitatory subfields substantially differed in their preferred orientations and spatial frequencies. Over 80% of V2 neurons in both infants and adults had "tuned" suppressive profiles in their subfield maps that could alter the tuning properties of facilitatory profiles. The differences in the preferred orientations between facilitatory and suppressive profiles were relatively large but extended over a broad range. Response immaturities in infants were mild; the overall strength of facilitatory subfield responses was lower than that in adults, and the optimal correlation delay ("latency") was longer in 4-week-old infants. These results suggest that as early as 4 weeks of age, the spatial receptive-field structure of V2 neurons is as complex as in adults and the ability of V2 neurons to compare local features of neighboring stimulus elements is nearly adult like.

MARs Tools for Interactive ANalysis (MARTIAN): Google Maps Tools for Visual Exploration of Geophysical Modeling on Mars

NASA Astrophysics Data System (ADS)

Dimitrova, L. L.; Haines, M.; Holt, W. E.; Schultz, R. A.; Richard, G.; Haines, A. J.

2006-12-01

Interactive maps of surface-breaking faults and stress models on Mars provide important tools to engage undergraduate students, educators, and scientists with current geological and geophysical research. We have developed a map based on the Google Maps API -- an Internet based tool combining DHTML and AJAX, -- which allows very large maps to be viewed over the World Wide Web. Typically, small portions of the maps are downloaded as needed, rather than the entire image at once. This set-up enables relatively fast access for users with low bandwidth. Furthermore, Google Maps provides an extensible interactive interface making it ideal for visualizing multiple data sets at the user's choice. The Google Maps API works primarily with data referenced to latitudes and longitudes, which is then mapped in Mercator projection only. We have developed utilities for general cylindrical coordinate systems by converting these coordinates into equivalent Mercator projection before including them on the map. The MARTIAN project is available at http://rock.geo.sunysb.edu/~holt/Mars/MARTIAN/. We begin with an introduction to the Martian surface using a topography model. Faults from several datasets are classified by type (extension vs. compression) and by time epoch. Deviatoric stresses due to gravitational potential energy differences, calculated from the topography and crustal thickness, can be overlain. Several quantitative measures for the fit of the stress field to the faults are also included. We provide introductory text and exercises spanning a range of topics: how are faults identified, what stress is and how it relates to faults, what gravitational potential energy is and how variations in it produce stress, how the models are created, and how these models can be evaluated and interpreted. The MARTIAN tool is used at Stony Brook University in GEO 310: Introduction to Geophysics, a class geared towards junior and senior geosciences majors. Although this project is in its early stages, high school and college teachers, as well as researchers have expressed interest in using and extending these tools for visualizing and interacting with data on Earth and other planetary bodies.

Teaching with AR as a Tool for Relief Visualization: Usability and Motivation Study

ERIC Educational Resources Information Center

Carrera, Carlos Carbonell; Perez, Jose Luis Saorin; Cantero, Jorge de la Torre

2018-01-01

In the field of geographical and environmental education, maps and geo-referenced information are frequently used, in which the earth's surfaces are represented in a two-dimensional (2D) way. Students have difficulty interpreting the relief representation and switching between 2D and 3D scenarios. Digital terrain modelling is added to the…

Association mapping analysis of the response to Macrophomina phaseolina in the Andean Diversity Panel

USDA-ARS?s Scientific Manuscript database

The Andean Diversity Panel was evaluated for response to inoculation with charcoal rot in a field trial in Isabela, Puerto Rico in 2012. The trial was inoculated with backpack sprayers at flowering and a visual evaluation was conducted three weeks later. There was a broad range of response, with abo...

GeoWall use in an Introductory Geology laboratory: Impacts in Student Understanding of Field Mapping Concepts

NASA Astrophysics Data System (ADS)

Ross, L. E.; Kelly, M.; Springer, A. E.

2003-12-01

In the Fall semester of 2003, Northern Arizona University will introduce the GeoWall to its introductory geology courses. This presents an opportunity to assess the impact of this new technology on students' understanding of basic topographic concepts and the spatial relationships between geology, topography, and hydrology on a field trip. Introductory Geology fulfills the Lab Science component of the Liberal Studies Program at Northern Arizona University. The class is open to all Northern Arizona University students, and is most commonly taken by non-science majors. In this class students learn to: locate their position using maps, identify common minerals and rocks, recognize the relationship between geology and geomorphology, visualize how rocks exposed at the surface continue into the subsurface, and to draw conclusions about possible geologic hazards in different settings. In this study we will report how a GeoWall 3D visualization technology was used in a field study of a graben south of Flagstaff. The goal of the field exercise is to improve students' ability to synthesize data collected at field stops into a conceptual model of the graben, linking geology, geomorphology and hydrology. We plan to present a quantitative assessment of the GeoWall learning objectives from data collected from a paired test and control group of students. Teaching assistants (TAs) with two or more lab classes have been identified; these TAs will participate in both GeoWall and non-GeoWall lab exercises. The GeoWall use will occur outside of normal lab hours to avoid disrupting the lab schedule during the eighth week of lab. This field preparation exercise includes a 3D visualization of the Lake Mary graben rendered with the ROMA software. The following week, all students attend the graben field trip; immediately following the trip, students will interviewed about their gain in understanding of the geologic features illustrated during the field trip. The results of the post-fieldtrip interviews will also be presented to quantitatively assess how students perceive the use of the GeoWall in this introductory geology setting, and how it affected their understanding.

3D seismic data interpretation of Boonsville Field, Texas

NASA Astrophysics Data System (ADS)

Alhakeem, Aamer Ali

The Boonsville field is one of the largest gas fields in the US located in the Fort Worth Basin, north central Texas. The highest potential reservoirs reside in the Bend Conglomerate deposited during the Pennsylvanian. The Boonsville data set is prepared by the Bureau of Economic Geology at the University of Texas, Austin, as part of the secondary gas recovery program. The Boonsville field seismic data set covers an area of 5.5 mi2. It includes 38 wells data. The Bend Conglomerate is deposited in fluvio-deltaic transaction. It is subdivided into many genetic sequences which include depositions of sandy conglomerate representing the potential reserves in the Boonsville field. The geologic structure of the Boonsville field subsurface are visualized by constructing structure maps of Caddo, Davis, Runaway, Beans Cr, Vineyard, and Wade. The mapping includes time structure, depth structure, horizon slice, velocity maps, and isopach maps. Many anticlines and folds are illustrated. Karst collapse features are indicated specially in the lower Atoka. Dipping direction of the Bend Conglomerate horizons are changing from dipping toward north at the top to dipping toward east at the bottom. Stratigraphic interpretation of the Runaway Formation and the Vineyard Formation using well logs and seismic data integration showed presence of fluvial dominated channels, point bars, and a mouth bar. RMS amplitude maps are generated and used as direct hydrocarbon indicator for the targeted formations. As a result, bright spots are indicated and used to identify potential reservoirs. Petrophysical analysis is conducted to obtain gross, net pay, NGR, water saturation, shale volume, porosity, and gas formation factor. Volumetric calculations estimated 989.44 MMSCF as the recoverable original gas in-place for a prospect in the Runaway and 3.32 BSCF for a prospect in the Vineyard Formation.

Visual area of the lateral suprasylvian gyrus (Clare—Bishop area) of the cat

PubMed Central

Hubel, David H.; Wiesel, Torsten N.

1969-01-01

On anatomical and physiological grounds a zone of cat cortex deep in the medial bank of the suprasylvian sulcus (the Clare—Bishop area) is known to receive strong visual projections both from the lateral geniculate body and area 17. We have mapped receptive fields of single cells in this area in eight cats. Active responses to visual stimuli were found over most of the medial bank of the suprasylvian sulcus extending to the depths and over to the lowest part of the lateral bank. The area is clearly topographically arranged. The first responsive cells, recorded over the lateral convexity and 2-3 mm down the medial bank, had receptive fields in the far periphery of the contralateral visual fields. The receptive fields tended to be large, but showed considerable variation in size and scatter in their positions. As the electrode advanced down the bank, fields of successively recorded cells gradually tended to move inwards, so that in the depths of the sulcus the inner borders of many of the fields reached the vertical mid line. Here the fields were smaller, though they still varied very much in size. Receptive fields were larger than in 17, 18, or 19, but otherwise were not obviously different from the complex and lower-order hypercomplex fields in those areas. No simple fields, or concentric fields of the retino-geniculate type, were seen. Cells with common receptive-field orientation were grouped together, but whether or not the grouping occurs in columns was not established. Most cells were driven independently by the two eyes. Fields in the two eyes seemed to be identical in organization. Cells dominated by the contralateral eye were much more common than ipsilaterally dominated ones, but when cells with parafoveal and peripheral fields were considered separately, the asymmetry was seen to apply mainly to cells with peripheral fields. PMID:5770897

Visualization tool for the world ocean surface currents

NASA Astrophysics Data System (ADS)

Kasyanov, S.; Nikitin, O.

2003-04-01

Fortran-based software for the world ocean surface currents visualization functioning on the Windows platform (95 and higher) has been developed. The software works with the global interpolated drifting buoys data set (1979-2002) from the WOCE Surface Velocity Program and the global bottom relief five-minute resolution data set (ETOPO5). These data sets loaded in binary form into operative memory of a PC (256 Mb or better more), together with the software compose the world ocean surface currents visualization tool. The tool allows researches to process data on-line in any region of the world ocean, display data in different visualization forms, calculate currents velocity statistics and save chosen images as graphic files. It provides displays of buoy movement (animation), maps of buoy trajectories, averaged (by prescribed time and space grid intervals) current vector and modulus fields, fields of current mean and eddy kinetic energies and their ratio, current steadiness coefficient and sea surface temperature. Any trajectory may be selected simply by clicking it on any summary map of trajectories (or by given buoy number). It may then be viewed and analyzed in detail, while graphs of velocity (components, module and vector) and water temperature variations along this trajectory may be displayed. The description of the previous version of the tool and some screen shots are available at http://zhurnal.ape.relarn.ru/articles/2001/154.pdf(in Russian) and will be available (in English) at http://csit.ugatu.ac.ru (CSIT '2001, Proceedings, v.2, p. 32-41, Nikitin O.P. et al).

Damage Evaluation Based on a Wave Energy Flow Map Using Multiple PZT Sensors

PubMed Central

Liu, Yaolu; Hu, Ning; Xu, Hong; Yuan, Weifeng; Yan, Cheng; Li, Yuan; Goda, Riu; Alamusi; Qiu, Jinhao; Ning, Huiming; Wu, Liangke

2014-01-01

A new wave energy flow (WEF) map concept was proposed in this work. Based on it, an improved technique incorporating the laser scanning method and Betti's reciprocal theorem was developed to evaluate the shape and size of damage as well as to realize visualization of wave propagation. In this technique, a simple signal processing algorithm was proposed to construct the WEF map when waves propagate through an inspection region, and multiple lead zirconate titanate (PZT) sensors were employed to improve inspection reliability. Various damages in aluminum and carbon fiber reinforced plastic laminated plates were experimentally and numerically evaluated to validate this technique. The results show that it can effectively evaluate the shape and size of damage from wave field variations around the damage in the WEF map. PMID:24463430

Awake surgery between art and science. Part II: language and cognitive mapping

PubMed Central

Talacchi, Andrea; Santini, Barbara; Casartelli, Marilena; Monti, Alessia; Capasso, Rita; Miceli, Gabriele

Summary Direct cortical and subcortical stimulation has been claimed to be the gold standard for exploring brain function. In this field, efforts are now being made to move from intraoperative naming-assisted surgical resection towards the use of other language and cognitive tasks. However, before relying on new protocols and new techniques, we need a multi-staged system of evidence (low and high) relating to each step of functional mapping and its clinical validity. In this article we examine the possibilities and limits of brain mapping with the aid of a visual object naming task and various other tasks used to date. The methodological aspects of intraoperative brain mapping, as well as the clinical and operative settings, were discussed in Part I of this review. PMID:24139658

Functional Connectivity Between Superior Parietal Lobule and Primary Visual Cortex "at Rest" Predicts Visual Search Efficiency.

PubMed

Bueichekú, Elisenda; Ventura-Campos, Noelia; Palomar-García, María-Ángeles; Miró-Padilla, Anna; Parcet, María-Antonia; Ávila, César

2015-10-01

Spatiotemporal activity that emerges spontaneously "at rest" has been proposed to reflect individual a priori biases in cognitive processing. This research focused on testing neurocognitive models of visual attention by studying the functional connectivity (FC) of the superior parietal lobule (SPL), given its central role in establishing priority maps during visual search tasks. Twenty-three human participants completed a functional magnetic resonance imaging session that featured a resting-state scan, followed by a visual search task based on the alphanumeric category effect. As expected, the behavioral results showed longer reaction times and more errors for the within-category (i.e., searching a target letter among letters) than the between-category search (i.e., searching a target letter among numbers). The within-category condition was related to greater activation of the superior and inferior parietal lobules, occipital cortex, inferior frontal cortex, dorsal anterior cingulate cortex, and the superior colliculus than the between-category search. The resting-state FC analysis of the SPL revealed a broad network that included connections with the inferotemporal cortex, dorsolateral prefrontal cortex, and dorsal frontal areas like the supplementary motor area and frontal eye field. Noteworthy, the regression analysis revealed that the more efficient participants in the visual search showed stronger FC between the SPL and areas of primary visual cortex (V1) related to the search task. We shed some light on how the SPL establishes a priority map of the environment during visual attention tasks and how FC is a valuable tool for assessing individual differences while performing cognitive tasks.

Non-invasive pulmonary blood flow analysis and blood pressure mapping derived from 4D flow MRI

NASA Astrophysics Data System (ADS)

Delles, Michael; Rengier, Fabian; Azad, Yoo-Jin; Bodenstedt, Sebastian; von Tengg-Kobligk, Hendrik; Ley, Sebastian; Unterhinninghofen, Roland; Kauczor, Hans-Ulrich; Dillmann, Rüdiger

2015-03-01

In diagnostics and therapy control of cardiovascular diseases, detailed knowledge about the patient-specific behavior of blood flow and pressure can be essential. The only method capable of measuring complete time-resolved three-dimensional vector fields of the blood flow velocities is velocity-encoded magnetic resonance imaging (MRI), often denoted as 4D flow MRI. Furthermore, relative pressure maps can be computed from this data source, as presented by different groups in recent years. Hence, analysis of blood flow and pressure using 4D flow MRI can be a valuable technique in management of cardiovascular diseases. In order to perform these tasks, all necessary steps in the corresponding process chain can be carried out in our in-house developed software framework MEDIFRAME. In this article, we apply MEDIFRAME for a study of hemodynamics in the pulmonary arteries of five healthy volunteers. The study included measuring vector fields of blood flow velocities by phase-contrast MRI and subsequently computing relative blood pressure maps. We visualized blood flow by streamline depictions and computed characteristic values for the left and the right pulmonary artery (LPA and RPA). In all volunteers, we observed a lower amount of blood flow in the LPA compared to the RPA. Furthermore, we visualized blood pressure maps using volume rendering and generated graphs of pressure differences between the LPA, the RPA and the main pulmonary artery. In most volunteers, blood pressure was increased near to the bifurcation and in the proximal LPA, leading to higher average pressure values in the LPA compared to the RPA.

Properties of the statpac visual field index.

PubMed

Artes, Paul H; O'Leary, Neil; Hutchison, Donna M; Heckler, Lisa; Sharpe, Glen P; Nicolela, Marcelo T; Chauhan, Balwantray C

2011-06-08

Purpose. To compare the properties of the visual field index (VFI) to those of mean deviation (MD) in patients with glaucoma. Methods. MD and VFI were calculated in data obtained from an ongoing longitudinal study in which patients with glaucoma (N = 109, 204 eyes) were observed for 9.8 years (median, 21 tests) with static automated perimetry. MD and VFI were compared in one test of each eye, and a subset of 30 tests were selected to compare the VFI with the judgments of eight experts who judged the percentage of the remaining visual field. In series of tests obtained over time, rates of change, statistical significance, evidence of nonlinearity, and variability were compared between both indices. Results. In single tests, MD and VFI were closely related (r = 0.88, P < 0.001). The relationship between both indices appeared linear, except in visual fields with MDs better than -5.0 dB where 29 (22%) of 129 eyes exhibited a ceiling effect (VFI = 100%). Based on this relationship, the predicted VFIs for visual fields with MDs of -5, -10, and -15 dB were 91%, 76%, and 60%, respectively. The percentage of remaining visual field suggested by the VFI exceeded the range of the experts' subjective judgments in 16 (53%) of 30 eyes. In series of tests obtained over time, rates of change with the two indices were closely related (r = 0.79, P < 0.001), and statistically significant reductions over time (P < 0.05) occurred in a similar number of eyes (92 [45%] with MD, and 87 [43%] with VFI). Of the 105 eyes with statistically significant (P < 0.05) negative trend in either MD or VFI, 74 (70%) showed such trends with both indices (κ = 0.69). The variability of MD and VFI increased with damage, and there was no evidence that change over time was more linear with VFI than with MD. Conclusions. The VFI provides a simple and understandable metric of visual field damage, but its estimates of remaining visual field were more optimistic than those of the experts. Rates of change over time with both indices were closely related, but the reliance of the VFI on pattern deviation probability maps caused a ceiling effect that may have reduced its sensitivity to change in eyes with early damage. In this group of patients there was no evidence to suggest that the VFI is either superior or inferior to the MD as a summary measure of visual field damage.

Modeling Color Difference for Visualization Design.

PubMed

Szafir, Danielle Albers

2018-01-01

Color is frequently used to encode values in visualizations. For color encodings to be effective, the mapping between colors and values must preserve important differences in the data. However, most guidelines for effective color choice in visualization are based on either color perceptions measured using large, uniform fields in optimal viewing environments or on qualitative intuitions. These limitations may cause data misinterpretation in visualizations, which frequently use small, elongated marks. Our goal is to develop quantitative metrics to help people use color more effectively in visualizations. We present a series of crowdsourced studies measuring color difference perceptions for three common mark types: points, bars, and lines. Our results indicate that peoples' abilities to perceive color differences varies significantly across mark types. Probabilistic models constructed from the resulting data can provide objective guidance for designers, allowing them to anticipate viewer perceptions in order to inform effective encoding design.

NaviCell Web Service for network-based data visualization.

PubMed

Bonnet, Eric; Viara, Eric; Kuperstein, Inna; Calzone, Laurence; Cohen, David P A; Barillot, Emmanuel; Zinovyev, Andrei

2015-07-01

Data visualization is an essential element of biological research, required for obtaining insights and formulating new hypotheses on mechanisms of health and disease. NaviCell Web Service is a tool for network-based visualization of 'omics' data which implements several data visual representation methods and utilities for combining them together. NaviCell Web Service uses Google Maps and semantic zooming to browse large biological network maps, represented in various formats, together with different types of the molecular data mapped on top of them. For achieving this, the tool provides standard heatmaps, barplots and glyphs as well as the novel map staining technique for grasping large-scale trends in numerical values (such as whole transcriptome) projected onto a pathway map. The web service provides a server mode, which allows automating visualization tasks and retrieving data from maps via RESTful (standard HTTP) calls. Bindings to different programming languages are provided (Python and R). We illustrate the purpose of the tool with several case studies using pathway maps created by different research groups, in which data visualization provides new insights into molecular mechanisms involved in systemic diseases such as cancer and neurodegenerative diseases. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

NaviCell Web Service for network-based data visualization

PubMed Central

Bonnet, Eric; Viara, Eric; Kuperstein, Inna; Calzone, Laurence; Cohen, David P. A.; Barillot, Emmanuel; Zinovyev, Andrei

2015-01-01

Data visualization is an essential element of biological research, required for obtaining insights and formulating new hypotheses on mechanisms of health and disease. NaviCell Web Service is a tool for network-based visualization of ‘omics’ data which implements several data visual representation methods and utilities for combining them together. NaviCell Web Service uses Google Maps and semantic zooming to browse large biological network maps, represented in various formats, together with different types of the molecular data mapped on top of them. For achieving this, the tool provides standard heatmaps, barplots and glyphs as well as the novel map staining technique for grasping large-scale trends in numerical values (such as whole transcriptome) projected onto a pathway map. The web service provides a server mode, which allows automating visualization tasks and retrieving data from maps via RESTful (standard HTTP) calls. Bindings to different programming languages are provided (Python and R). We illustrate the purpose of the tool with several case studies using pathway maps created by different research groups, in which data visualization provides new insights into molecular mechanisms involved in systemic diseases such as cancer and neurodegenerative diseases. PMID:25958393

SU-G-BRB-16: Vulnerabilities in the Gamma Metric

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neal, B; Siebers, J

Purpose: To explore vulnerabilities in the gamma index metric that undermine its wide use as a radiation therapy quality assurance tool. Methods: 2D test field pairs (images) are created specifically to achieve high gamma passing rates, but to also include gross errors by exploiting the distance-to-agreement and percent-passing components of the metric. The first set has no requirement of clinical practicality, but is intended to expose vulnerabilities. The second set exposes clinically realistic vulnerabilities. To circumvent limitations inherent to user-specific tuning of prediction algorithms to match measurements, digital test cases are manually constructed, thereby mimicking high-quality image prediction. Results: Withmore » a 3 mm distance-to-agreement metric, changing field size by ±6 mm results in a gamma passing rate over 99%. For a uniform field, a lattice of passing points spaced 5 mm apart results in a passing rate of 100%. Exploiting the percent-passing component, a 10×10 cm{sup 2} field can have a 95% passing rate when an 8 cm{sup 2}=2.8×2.8 cm{sup 2} highly out-of-tolerance (e.g. zero dose) square is missing from the comparison image. For clinically realistic vulnerabilities, an arc plan for which a 2D image is created can have a >95% passing rate solely due to agreement in the lateral spillage, with the failing 5% in the critical target region. A field with an integrated boost (e.g whole brain plus small metastases) could neglect the metastases entirely, yet still pass with a 95% threshold. All the failure modes described would be visually apparent on a gamma-map image. Conclusion: The %gamma<1 metric has significant vulnerabilities. High passing rates can obscure critical faults in hypothetical and delivered radiation doses. Great caution should be used with gamma as a QA metric; users should inspect the gamma-map. Visual analysis of gamma-maps may be impractical for cine acquisition.« less

The magnetic map sense and its use in fine-tuning the migration programme of birds.

PubMed

Heyers, D; Elbers, D; Bulte, M; Bairlein, F; Mouritsen, H

2017-07-01

The Earth's magnetic field is one of several natural cues, which migratory birds can use to derive directional ("compass") information for orientation on their biannual migratory journeys. Moreover, magnetic field effects on prominent aspects of the migratory programme of birds, such as migratory restlessness behaviour, fuel deposition and directional orientation, implicate that geomagnetic information can also be used to derive positional ("map") information. While the magnetic "compass" in migratory birds is likely to be based on radical pair-forming molecules embedded in their visual system, the sensory correlates underlying a magnetic "map" sense currently remain elusive. Behavioural, physiological and neurobiological findings indicate that the sensor is most likely innervated by the ophthalmic branch of the trigeminal nerve and based on magnetic iron particles. Information from this unknown sensor is neither necessary nor sufficient for a functional magnetic compass, but instead could contribute important components of a multifactorial "map" for global positioning. Positional information could allow migratory birds to make vitally important dynamic adaptations of their migratory programme at any relevant point during their journeys.

GPU-Based Interactive Exploration and Online Probability Maps Calculation for Visualizing Assimilated Ocean Ensembles Data

NASA Astrophysics Data System (ADS)

Hoteit, I.; Hollt, T.; Hadwiger, M.; Knio, O. M.; Gopalakrishnan, G.; Zhan, P.

2016-02-01

Ocean reanalyses and forecasts are nowadays generated by combining ensemble simulations with data assimilation techniques. Most of these techniques resample the ensemble members after each assimilation cycle. Tracking behavior over time, such as all possible paths of a particle in an ensemble vector field, becomes very difficult, as the number of combinations rises exponentially with the number of assimilation cycles. In general a single possible path is not of interest but only the probabilities that any point in space might be reached by a particle at some point in time. We present an approach using probability-weighted piecewise particle trajectories to allow for interactive probability mapping. This is achieved by binning the domain and splitting up the tracing process into the individual assimilation cycles, so that particles that fall into the same bin after a cycle can be treated as a single particle with a larger probability as input for the next cycle. As a result we loose the possibility to track individual particles, but can create probability maps for any desired seed at interactive rates. The technique is integrated in an interactive visualization system that enables the visual analysis of the particle traces side by side with other forecast variables, such as the sea surface height, and their corresponding behavior over time. By harnessing the power of modern graphics processing units (GPUs) for visualization as well as computation, our system allows the user to browse through the simulation ensembles in real-time, view specific parameter settings or simulation models and move between different spatial or temporal regions without delay. In addition our system provides advanced visualizations to highlight the uncertainty, or show the complete distribution of the simulations at user-defined positions over the complete time series of the domain.

Mapping the evolution of entrepreneurship as a field of research (1990–2013): A scientometric analysis

PubMed Central

2018-01-01

This article applies scientometric techniques to study the evolution of the field of entrepreneurship between 1990 and 2013. Using a combination of topic mapping, author and journal co-citation analyses, and overlay visualization of new and hot topics in the field, this article makes important contribution to the entrepreneurship research by identifying 46 topics in the 24-year history of entrepreneurship research and demonstrates how they appear, disappear, reappear and stabilize over time. It also identifies five topics that are persistent across the 24-year study period––institutions and institutional entrepreneurship, innovation and technology management, policy and development, entrepreneurial process and opportunity, and new ventures––which I labeled as The Pentagon of Entrepreneurship. Overall, the analyses revealed patterns of convergence and divergence and the diversity of topics, specialization, and interdisciplinary engagement in entrepreneurship research, thus offering the latest insights on the state of the art of the field. PMID:29300735

Neural network models for spatial data mining, map production, and cortical direction selectivity

NASA Astrophysics Data System (ADS)

Parsons, Olga

A family of ARTMAP neural networks for incremental supervised learning has been developed over the last decade. The Sensor Exploitation Group of MIT Lincoln Laboratory (LL) has incorporated an early version of this network as the recognition engine of a hierarchical system for fusion and data mining of multiple registered geospatial images. The LL system has been successfully fielded, but it is limited to target vs. non-target identifications and does not produce whole maps. This dissertation expands the capabilities of the LL system so that it learns to identify arbitrarily many target classes at once and can thus produce a whole map. This new spatial data mining system is designed particularly to cope with the highly skewed class distributions of typical mapping problems. Specification of a consistent procedure and a benchmark testbed has permitted the evaluation of candidate recognition networks as well as pre- and post-processing and feature extraction options. The resulting default ARTMAP network and mapping methodology set a standard for a variety of related mapping problems and application domains. The second part of the dissertation investigates the development of cortical direction selectivity. The possible role of visual experience and oculomotor behavior in the maturation of cells in the primary visual cortex is studied. The responses of neurons in the thalamus and cortex of the cat are modeled when natural scenes are scanned by several types of eye movements. Inspired by the Hebbian-like synaptic plasticity, which is based upon correlations between cell activations, the second-order statistical structure of thalamo-cortical activity is examined. In the simulations, patterns of neural activity that lead to a correct refinement of cell responses are observed during visual fixation, when small ocular movements occur, but are not observed in the presence of large saccades. Simulations also replicate experiments in which kittens are reared under stroboscopic illumination. The abnormal fixational eye movements of these cats may account for the puzzling finding of a specific loss of cortical direction selectivity but preservation of orientation selectivity. This work indicates that the oculomotor behavior of visual fixation may play an important role in the refinement of cell response selectivity.

A tool for the estimation of the distribution of landslide area in R

NASA Astrophysics Data System (ADS)

Rossi, M.; Cardinali, M.; Fiorucci, F.; Marchesini, I.; Mondini, A. C.; Santangelo, M.; Ghosh, S.; Riguer, D. E. L.; Lahousse, T.; Chang, K. T.; Guzzetti, F.

2012-04-01

We have developed a tool in R (the free software environment for statistical computing, http://www.r-project.org/) to estimate the probability density and the frequency density of landslide area. The tool implements parametric and non-parametric approaches to the estimation of the probability density and the frequency density of landslide area, including: (i) Histogram Density Estimation (HDE), (ii) Kernel Density Estimation (KDE), and (iii) Maximum Likelihood Estimation (MLE). The tool is available as a standard Open Geospatial Consortium (OGC) Web Processing Service (WPS), and is accessible through the web using different GIS software clients. We tested the tool to compare Double Pareto and Inverse Gamma models for the probability density of landslide area in different geological, morphological and climatological settings, and to compare landslides shown in inventory maps prepared using different mapping techniques, including (i) field mapping, (ii) visual interpretation of monoscopic and stereoscopic aerial photographs, (iii) visual interpretation of monoscopic and stereoscopic VHR satellite images and (iv) semi-automatic detection and mapping from VHR satellite images. Results show that both models are applicable in different geomorphological settings. In most cases the two models provided very similar results. Non-parametric estimation methods (i.e., HDE and KDE) provided reasonable results for all the tested landslide datasets. For some of the datasets, MLE failed to provide a result, for convergence problems. The two tested models (Double Pareto and Inverse Gamma) resulted in very similar results for large and very large datasets (> 150 samples). Differences in the modeling results were observed for small datasets affected by systematic biases. A distinct rollover was observed in all analyzed landslide datasets, except for a few datasets obtained from landslide inventories prepared through field mapping or by semi-automatic mapping from VHR satellite imagery. The tool can also be used to evaluate the probability density and the frequency density of landslide volume.

Multimap formation in visual cortex

PubMed Central

Jain, Rishabh; Millin, Rachel; Mel, Bartlett W.

2015-01-01

An extrastriate visual area such as V2 or V4 contains neurons selective for a multitude of complex shapes, all sharing a common topographic organization. Simultaneously developing multiple interdigitated maps—hereafter a “multimap”—is challenging in that neurons must compete to generate a diversity of response types locally, while cooperating with their dispersed same-type neighbors to achieve uniform visual field coverage for their response type at all orientations, scales, etc. Previously proposed map development schemes have relied on smooth spatial interaction functions to establish both topography and columnar organization, but by locally homogenizing cells' response properties, local smoothing mechanisms effectively rule out multimap formation. We found in computer simulations that the key requirements for multimap development are that neurons are enabled for plasticity only within highly active regions of cortex designated “learning eligibility regions” (LERs), but within an LER, each cell's learning rate is determined only by its activity level with no dependence on location. We show that a hybrid developmental rule that combines spatial and activity-dependent learning criteria in this way successfully produces multimaps when the input stream contains multiple distinct feature types, or in the degenerate case of a single feature type, produces a V1-like map with “salt-and-pepper” structure. Our results support the hypothesis that cortical maps containing a fine mixture of different response types, whether in monkey extrastriate cortex, mouse V1 or elsewhere in the cortex, rather than signaling a breakdown of map formation mechanisms at the fine scale, are a product of a generic cortical developmental scheme designed to map cells with a diversity of response properties across a shared topographic space. PMID:26641946

Infrared and visible image fusion method based on saliency detection in sparse domain

NASA Astrophysics Data System (ADS)

Liu, C. H.; Qi, Y.; Ding, W. R.

2017-06-01

Infrared and visible image fusion is a key problem in the field of multi-sensor image fusion. To better preserve the significant information of the infrared and visible images in the final fused image, the saliency maps of the source images is introduced into the fusion procedure. Firstly, under the framework of the joint sparse representation (JSR) model, the global and local saliency maps of the source images are obtained based on sparse coefficients. Then, a saliency detection model is proposed, which combines the global and local saliency maps to generate an integrated saliency map. Finally, a weighted fusion algorithm based on the integrated saliency map is developed to achieve the fusion progress. The experimental results show that our method is superior to the state-of-the-art methods in terms of several universal quality evaluation indexes, as well as in the visual quality.

Developing a Very Low Vision Orientation and Mobility Test Battery (O&M-VLV).

PubMed

Finger, Robert P; Ayton, Lauren N; Deverell, Lil; O'Hare, Fleur; McSweeney, Shane C; Luu, Chi D; Fenwick, Eva K; Keeffe, Jill E; Guymer, Robyn H; Bentley, Sharon A

2016-09-01

This study aimed to determine the feasibility of an assessment of vision-related orientation and mobility (O&M) tasks in persons with severe vision loss. These tasks may be used for future low vision rehabilitation clinical assessments or as outcome measures in vision restoration trials. Forty legally blind persons (mean visual acuity logMAR 2.3, or hand movements) with advanced retinitis pigmentosa participated in the Orientation & Mobility-Very Low Vision (O&M-VLV) subtests from the Low Vision Assessment of Daily Activities (LoVADA) protocol. Four categories of tasks were evaluated: route travel in three indoor hospital environments, a room orientation task (the "cafe"), a visual exploration task (the "gallery"), and a modified version of the Timed Up and Go (TUG) test, which assesses re-orientation and route travel. Spatial cognition was assessed using the Stuart Tactile Maps test. Visual acuity and visual fields were measured. A generalized linear regression model showed that a number of measures in the O&M-VLV tasks were related to residual visual function. The percentage of preferred walking speed without an aid on three travel routes was associated with visual field (p < 0.01 for all routes) whereas the number of contacts with obstacles during route travel was associated with acuity (p = 0.001). TUG-LV task time was associated with acuity (p = 0.003), as was the cafe time and distance traveled (p = 0.006 and p < 0.001, respectively). The gallery score was the only measure that was significantly associated with both residual acuity and fields (p < 0.001 and p = 0.001, respectively). The O&M-VLV was designed to capture key elements of O&M performance in persons with severe vision loss, which is a population not often studied previously. Performance on these tasks was associated with both binocular visual acuity and visual field. This new protocol includes assessments of orientation, which may be of benefit in vision restoration clinical trials.

What Google Maps can do for biomedical data dissemination: examples and a design study.

PubMed

Jianu, Radu; Laidlaw, David H

2013-05-04

Biologists often need to assess whether unfamiliar datasets warrant the time investment required for more detailed exploration. Basing such assessments on brief descriptions provided by data publishers is unwieldy for large datasets that contain insights dependent on specific scientific questions. Alternatively, using complex software systems for a preliminary analysis may be deemed as too time consuming in itself, especially for unfamiliar data types and formats. This may lead to wasted analysis time and discarding of potentially useful data. We present an exploration of design opportunities that the Google Maps interface offers to biomedical data visualization. In particular, we focus on synergies between visualization techniques and Google Maps that facilitate the development of biological visualizations which have both low-overhead and sufficient expressivity to support the exploration of data at multiple scales. The methods we explore rely on displaying pre-rendered visualizations of biological data in browsers, with sparse yet powerful interactions, by using the Google Maps API. We structure our discussion around five visualizations: a gene co-regulation visualization, a heatmap viewer, a genome browser, a protein interaction network, and a planar visualization of white matter in the brain. Feedback from collaborative work with domain experts suggests that our Google Maps visualizations offer multiple, scale-dependent perspectives and can be particularly helpful for unfamiliar datasets due to their accessibility. We also find that users, particularly those less experienced with computer use, are attracted by the familiarity of the Google Maps API. Our five implementations introduce design elements that can benefit visualization developers. We describe a low-overhead approach that lets biologists access readily analyzed views of unfamiliar scientific datasets. We rely on pre-computed visualizations prepared by data experts, accompanied by sparse and intuitive interactions, and distributed via the familiar Google Maps framework. Our contributions are an evaluation demonstrating the validity and opportunities of this approach, a set of design guidelines benefiting those wanting to create such visualizations, and five concrete example visualizations.

What google maps can do for biomedical data dissemination: examples and a design study

PubMed Central

2013-01-01

Background Biologists often need to assess whether unfamiliar datasets warrant the time investment required for more detailed exploration. Basing such assessments on brief descriptions provided by data publishers is unwieldy for large datasets that contain insights dependent on specific scientific questions. Alternatively, using complex software systems for a preliminary analysis may be deemed as too time consuming in itself, especially for unfamiliar data types and formats. This may lead to wasted analysis time and discarding of potentially useful data. Results We present an exploration of design opportunities that the Google Maps interface offers to biomedical data visualization. In particular, we focus on synergies between visualization techniques and Google Maps that facilitate the development of biological visualizations which have both low-overhead and sufficient expressivity to support the exploration of data at multiple scales. The methods we explore rely on displaying pre-rendered visualizations of biological data in browsers, with sparse yet powerful interactions, by using the Google Maps API. We structure our discussion around five visualizations: a gene co-regulation visualization, a heatmap viewer, a genome browser, a protein interaction network, and a planar visualization of white matter in the brain. Feedback from collaborative work with domain experts suggests that our Google Maps visualizations offer multiple, scale-dependent perspectives and can be particularly helpful for unfamiliar datasets due to their accessibility. We also find that users, particularly those less experienced with computer use, are attracted by the familiarity of the Google Maps API. Our five implementations introduce design elements that can benefit visualization developers. Conclusions We describe a low-overhead approach that lets biologists access readily analyzed views of unfamiliar scientific datasets. We rely on pre-computed visualizations prepared by data experts, accompanied by sparse and intuitive interactions, and distributed via the familiar Google Maps framework. Our contributions are an evaluation demonstrating the validity and opportunities of this approach, a set of design guidelines benefiting those wanting to create such visualizations, and five concrete example visualizations. PMID:23642009

Functional Architecture for Disparity in Macaque Inferior Temporal Cortex and Its Relationship to the Architecture for Faces, Color, Scenes, and Visual Field

PubMed Central

Verhoef, Bram-Ernst; Bohon, Kaitlin S.

2015-01-01

Binocular disparity is a powerful depth cue for object perception. The computations for object vision culminate in inferior temporal cortex (IT), but the functional organization for disparity in IT is unknown. Here we addressed this question by measuring fMRI responses in alert monkeys to stimuli that appeared in front of (near), behind (far), or at the fixation plane. We discovered three regions that showed preferential responses for near and far stimuli, relative to zero-disparity stimuli at the fixation plane. These “near/far” disparity-biased regions were located within dorsal IT, as predicted by microelectrode studies, and on the posterior inferotemporal gyrus. In a second analysis, we instead compared responses to near stimuli with responses to far stimuli and discovered a separate network of “near” disparity-biased regions that extended along the crest of the superior temporal sulcus. We also measured in the same animals fMRI responses to faces, scenes, color, and checkerboard annuli at different visual field eccentricities. Disparity-biased regions defined in either analysis did not show a color bias, suggesting that disparity and color contribute to different computations within IT. Scene-biased regions responded preferentially to near and far stimuli (compared with stimuli without disparity) and had a peripheral visual field bias, whereas face patches had a marked near bias and a central visual field bias. These results support the idea that IT is organized by a coarse eccentricity map, and show that disparity likely contributes to computations associated with both central (face processing) and peripheral (scene processing) visual field biases, but likely does not contribute much to computations within IT that are implicated in processing color. PMID:25926470

Areas activated during naturalistic reading comprehension overlap topological visual, auditory, and somatotomotor maps

PubMed Central

2016-01-01

Abstract Cortical mapping techniques using fMRI have been instrumental in identifying the boundaries of topological (neighbor‐preserving) maps in early sensory areas. The presence of topological maps beyond early sensory areas raises the possibility that they might play a significant role in other cognitive systems, and that topological mapping might help to delineate areas involved in higher cognitive processes. In this study, we combine surface‐based visual, auditory, and somatomotor mapping methods with a naturalistic reading comprehension task in the same group of subjects to provide a qualitative and quantitative assessment of the cortical overlap between sensory‐motor maps in all major sensory modalities, and reading processing regions. Our results suggest that cortical activation during naturalistic reading comprehension overlaps more extensively with topological sensory‐motor maps than has been heretofore appreciated. Reading activation in regions adjacent to occipital lobe and inferior parietal lobe almost completely overlaps visual maps, whereas a significant portion of frontal activation for reading in dorsolateral and ventral prefrontal cortex overlaps both visual and auditory maps. Even classical language regions in superior temporal cortex are partially overlapped by topological visual and auditory maps. By contrast, the main overlap with somatomotor maps is restricted to a small region on the anterior bank of the central sulcus near the border between the face and hand representations of M‐I. Hum Brain Mapp 37:2784–2810, 2016. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc. PMID:27061771

Synthesis maps: visual knowledge translation for the CanIMPACT clinical system and patient cancer journeys.

PubMed

Jones, P H; Shakdher, S; Singh, P

2017-04-01

Salient findings and interpretations from the canimpact clinical cancer research study are visually represented in two synthesis maps for the purpose of communicating an integrated presentation of the study to clinical cancer researchers and policymakers. Synthesis maps integrate evidence and expertise into a visual narrative for knowledge translation and communication. A clinical system synthesis map represents the current Canadian primary care and cancer practice systems, proposed as a visual knowledge translation from the mixed-methods canimpact study to inform Canadian clinical research, policy, and practice discourses. Two synthesis maps, drawn together from multiple canimpact investigations and sources, were required to articulate critical differences between the clinical system and patient perspectives. The synthesis map of Canada-wide clinical cancer systems illustrates the relationships between primary care and the full cancer continuum. A patient-centred map was developed to represent the cancer (and primary care) journeys as experienced by breast and colorectal cancer patients.

Participatory GIS in design of the Wroclaw University of Science and Technology campus web map and spatial analysis of campus area quality

NASA Astrophysics Data System (ADS)

Blachowski, Jan; Łuczak, Jakub; Zagrodnik, Paulina

2018-01-01

Public participation geographic information system (GIS) and participatory mapping data collection methods are means that enhance capacity in generating, managing, and communicating spatial information in various fields ranging from local planning to environmental management. In this study these methods have been used in two ways. The first one, to gather information on the additional functionality of campus web map expected by its potential users, i.e. students, staff and visitors, through web based survey. The second, to collect geographically referenced information on campus areas that are liked and disliked in a geo-survey carried out with ArcGIS Online GeoForm Application. The results of the first survey were used to map facilities such as: bicycle infrastructure, building entrances, wheelchair accessible infrastructure and benches. The results of the second one, to analyse the most and the least attractive parts of the campus with heat and hot spot analyses in GIS. In addition, the answers have been studied with regard to the visual and functional aspects of campus area raised in the survey. The thematic layers developed in the results of field mapping and geoprocessing of geosurvey data were included in the campus web map project. The paper describes the applied methodology of data collection, processing, analysis, interpretation and geovisualisation.

Computational Model of Primary Visual Cortex Combining Visual Attention for Action Recognition

PubMed Central

Shu, Na; Gao, Zhiyong; Chen, Xiangan; Liu, Haihua

2015-01-01

Humans can easily understand other people’s actions through visual systems, while computers cannot. Therefore, a new bio-inspired computational model is proposed in this paper aiming for automatic action recognition. The model focuses on dynamic properties of neurons and neural networks in the primary visual cortex (V1), and simulates the procedure of information processing in V1, which consists of visual perception, visual attention and representation of human action. In our model, a family of the three-dimensional spatial-temporal correlative Gabor filters is used to model the dynamic properties of the classical receptive field of V1 simple cell tuned to different speeds and orientations in time for detection of spatiotemporal information from video sequences. Based on the inhibitory effect of stimuli outside the classical receptive field caused by lateral connections of spiking neuron networks in V1, we propose surround suppressive operator to further process spatiotemporal information. Visual attention model based on perceptual grouping is integrated into our model to filter and group different regions. Moreover, in order to represent the human action, we consider the characteristic of the neural code: mean motion map based on analysis of spike trains generated by spiking neurons. The experimental evaluation on some publicly available action datasets and comparison with the state-of-the-art approaches demonstrate the superior performance of the proposed model. PMID:26132270

An interactive mapping tool for visualizing lacunarity of laser scanned point clouds

NASA Astrophysics Data System (ADS)

Kania, Adam; Székely, Balázs

2016-04-01

Lacunarity, a measure of the spatial distribution of the empty space in a certain model or real space over large spatial scales, is found to be a useful descriptive quantity in many fields using imagery, including, among others, geology, dentistry, neurology. Its application in ecology was suggested more than 20 years ago. The main problem of its application was the lack of appropriate high resolution data. Nowadays, full-waveform laser scanning, also known as FWF LiDAR, provides the tool for mapping the vegetation in unprecedented details and accuracy. Consequently, the lacunarity concept can be revitalized, in order to study the structure of the vegetation in this sense as well. Calculation of lacunarity, even if it is done in two dimensions (2D), is still has its problems: on one hand it is a number-crunching procedure, on the other hand, it produces 4D results: at each 3D point it returns a set of data that are function of scale. These data sets are difficult to visualize, to evaluate, and to compare. In order to solve this problem, an interactive mapping tool has been conceptualized that is designed to manipulate and visualize the data, lets the user set parameters for best visualization or comparison results. The system is able to load large amounts of data, visualize them as lacunarity curves, or map view as horizontal slices or in 3D point clouds coloured according to the user's choice. Lacunarity maps are presented as a series of (usually) horizontal profiles, e.g. rasters, which cells contain color-mapped values of selected lacunarity of the point cloud. As lacunarity is usually analysed in a series of successive windows sizes, the tool can show a series of rasters with sequentially animated lacunarity maps calculated for various window sizes. A very fast switching of colour schemes is possible to facilitate rapid visual feedback to better understand underlying data patterns exposed by lacunarity functions. In the comparison mode, two sites (or two areas of the same site) can be visualized using the same settings. Basic output/export operations are supported, as well as text and numerical format to utilize the calculated lacunarity values. Furthermore, the system is able to export data to standard georeferenced image and GIS formats enabling further processing and integration with other observational data, like GPS coordinates of forest damages, human influence (illegal tree cut, waste dumps), abundance of species or other ecological indicators. The use of the system is easy to learn and, via the export functionality, it provides interoperability with most of the GIS and other software tools applied in spatial ecological applications. Some LiDAR data of the ChangeHabitats2 project (an IAPP of Marie Curie Actions of the European Commission) have been used for demonstration purposes. BSz contributed as an Alexander von Humboldt Research Fellow.

Constructing Concept Maps to Encourage Meaningful Learning in Science Classroom

ERIC Educational Resources Information Center

Akcay, Hakan

2017-01-01

The purpose of this activity is to demonstrate science teaching and assessing what is learned via using concept maps. Concept mapping is a technique for visually representing the structure of information. Concept mapping allows students to understand the relationships between concepts of science by creating a visual map of the connections. Concept…

Open Touch/Sound Maps: A system to convey street data through haptic and auditory feedback

NASA Astrophysics Data System (ADS)

Kaklanis, Nikolaos; Votis, Konstantinos; Tzovaras, Dimitrios

2013-08-01

The use of spatial (geographic) information is becoming ever more central and pervasive in today's internet society but the most of it is currently inaccessible to visually impaired users. However, access in visual maps is severely restricted to visually impaired and people with blindness, due to their inability to interpret graphical information. Thus, alternative ways of a map's presentation have to be explored, in order to enforce the accessibility of maps. Multiple types of sensory perception like touch and hearing may work as a substitute of vision for the exploration of maps. The use of multimodal virtual environments seems to be a promising alternative for people with visual impairments. The present paper introduces a tool for automatic multimodal map generation having haptic and audio feedback using OpenStreetMap data. For a desired map area, an elevation map is being automatically generated and can be explored by touch, using a haptic device. A sonification and a text-to-speech (TTS) mechanism provide also audio navigation information during the haptic exploration of the map.

Dynamic Digital Maps as Vehicles for Distributing Digital Geologic Maps and Embedded Analytical Data and Multimedia

NASA Astrophysics Data System (ADS)

Condit, C. D.; Mninch, M.

2012-12-01

The Dynamic Digital Map (DDM) is an ideal vehicle for the professional geologist to use to describe the geologic setting of key sites to the public in a format that integrates and presents maps and associated analytical data and multimedia without the need for an ArcGIS interface. Maps with field trip guide stops that include photographs, movies and figures and animations, showing, for example, how the features seen in the field formed, or how data might be best visualized in "time-frame" sequences are ideally included in DDMs. DDMs distribute geologic maps, images, movies, analytical data, and text such as field guides, in an integrated cross-platform, web enabled format that are intuitive to use, easily and quickly searchable, and require no additional proprietary software to operate. Maps, photos, movies and animations are stored outside the program, which acts as an organizational framework and index to present these data. Once created, the DDM can be downloaded from the web site hosting it in the flavor matching the user's operating system (e.g. Linux, Windows and Macintosh) as zip, dmg or tar files (and soon as iOS and Android tablet apps). When decompressed, the DDM can then access its associated data directly from that site with no browser needed. Alternatively, the entire package can be distributed and used from CD, DVD, or flash-memory storage. The intent of this presentation is to introduce the variety of geology that can be accessed from the over 25 DDMs created to date, concentrating on the DDM of the Springerville Volcanic Field. We will highlight selected features of some of them, introduce a simplified interface to the original DDM (that we renamed DDMC for Classic) and give a brief look at a the recently (2010-2011) completed geologic maps of the Springerville Volcanic field to see examples of each of the features discussed above, and a display of the integrated analytical data set. We will also highlight the differences between the classic or DDMCs and the new Dynamic Digital Map Extended (DDME) designed from the ground up to take advantage of the expanded connectedness this redesigned program will accommodate.

ViA: a perceptual visualization assistant

NASA Astrophysics Data System (ADS)

Healey, Chris G.; St. Amant, Robert; Elhaddad, Mahmoud S.

2000-05-01

This paper describes an automated visualized assistant called ViA. ViA is designed to help users construct perceptually optical visualizations to represent, explore, and analyze large, complex, multidimensional datasets. We have approached this problem by studying what is known about the control of human visual attention. By harnessing the low-level human visual system, we can support our dual goals of rapid and accurate visualization. Perceptual guidelines that we have built using psychophysical experiments form the basis for ViA. ViA uses modified mixed-initiative planning algorithms from artificial intelligence to search of perceptually optical data attribute to visual feature mappings. Our perceptual guidelines are integrated into evaluation engines that provide evaluation weights for a given data-feature mapping, and hints on how that mapping might be improved. ViA begins by asking users a set of simple questions about their dataset and the analysis tasks they want to perform. Answers to these questions are used in combination with the evaluation engines to identify and intelligently pursue promising data-feature mappings. The result is an automatically-generated set of mappings that are perceptually salient, but that also respect the context of the dataset and users' preferences about how they want to visualize their data.

Retinotopic maps and foveal suppression in the visual cortex of amblyopic adults.

PubMed

Conner, Ian P; Odom, J Vernon; Schwartz, Terry L; Mendola, Janine D

2007-08-15

Amblyopia is a developmental visual disorder associated with loss of monocular acuity and sensitivity as well as profound alterations in binocular integration. Abnormal connections in visual cortex are known to underlie this loss, but the extent to which these abnormalities are regionally or retinotopically specific has not been fully determined. This functional magnetic resonance imaging (fMRI) study compared the retinotopic maps in visual cortex produced by each individual eye in 19 adults (7 esotropic strabismics, 6 anisometropes and 6 controls). In our standard viewing condition, the non-tested eye viewed a dichoptic homogeneous mid-level grey stimulus, thereby permitting some degree of binocular interaction. Regions-of-interest analysis was performed for extrafoveal V1, extrafoveal V2 and the foveal representation at the occipital pole. In general, the blood oxygenation level-dependent (BOLD) signal was reduced for the amblyopic eye. At the occipital pole, population receptive fields were shifted to represent more parafoveal locations for the amblyopic eye, compared with the fellow eye, in some subjects. Interestingly, occluding the fellow eye caused an expanded foveal representation for the amblyopic eye in one early-onset strabismic subject with binocular suppression, indicating real-time cortical remapping. In addition, a few subjects actually showed increased activity in parietal and temporal cortex when viewing with the amblyopic eye. We conclude that, even in a heterogeneous population, abnormal early visual experience commonly leads to regionally specific cortical adaptations.

Earth observations and photography experiment: Summary of significant results

NASA Technical Reports Server (NTRS)

El-Baz, F.

1978-01-01

Observation and photographic data from the Apollo Soyuz Test Project are analyzed. The discussion is structured according to the fields of investigation including: geology, desert studies, oceanography, hydrology, and meteorology. The data were obtained by: (1) visual observations of selected Earth features, (2) hand-held camera photography to document observations, and (3) stereo mapping photography of areas of significant scientific interest.

New Applications for the Testing and Visualization of Wireless Networks

NASA Technical Reports Server (NTRS)

Griffin, Robert I.; Cauley, Michael A.; Pleva, Michael A.; Seibert, Marc A.; Lopez, Isaac

2005-01-01

Traditional techniques for examining wireless networks use physical link characteristics such as Signal-to-Noise (SNR) ratios to assess the performance of wireless networks. Such measurements may not be reliable indicators of available bandwidth. This work describes two new software applications developed at NASA Glenn Research Center for the investigation of wireless networks. GPSIPerf combines measurements of Transmission Control Protocol (TCP) throughput with Global Positioning System (GPS) coordinates to give users a map of wireless bandwidth for outdoor environments where a wireless infrastructure has been deployed. GPSIPerfView combines the data provided by GPSIPerf with high-resolution digital elevation maps (DEM) to help users visualize and assess the impact of elevation features on wireless networks in a given sample area. These applications were used to examine TCP throughput in several wireless network configurations at desert field sites near Hanksville, Utah during May of 2004. Use of GPSIPerf and GPSIPerfView provides a geographically referenced picture of the extent and deterioration of TCP throughput in tested wireless network configurations. GPSIPerf results from field-testing in Utah suggest that it can be useful in assessing other wireless network architectures, and may be useful to future human-robotic exploration missions.

Current trends in geomorphological mapping

NASA Astrophysics Data System (ADS)

Seijmonsbergen, A. C.

2012-04-01

Geomorphological mapping is a world currently in motion, driven by technological advances and the availability of new high resolution data. As a consequence, classic (paper) geomorphological maps which were the standard for more than 50 years are rapidly being replaced by digital geomorphological information layers. This is witnessed by the following developments: 1. the conversion of classic paper maps into digital information layers, mainly performed in a digital mapping environment such as a Geographical Information System, 2. updating the location precision and the content of the converted maps, by adding more geomorphological details, taken from high resolution elevation data and/or high resolution image data, 3. (semi) automated extraction and classification of geomorphological features from digital elevation models, broadly separated into unsupervised and supervised classification techniques and 4. New digital visualization / cartographic techniques and reading interfaces. Newly digital geomorphological information layers can be based on manual digitization of polygons using DEMs and/or aerial photographs, or prepared through (semi) automated extraction and delineation of geomorphological features. DEMs are often used as basis to derive Land Surface Parameter information which is used as input for (un) supervised classification techniques. Especially when using high-res data, object-based classification is used as an alternative to traditional pixel-based classifications, to cluster grid cells into homogeneous objects, which can be classified as geomorphological features. Classic map content can also be used as training material for the supervised classification of geomorphological features. In the classification process, rule-based protocols, including expert-knowledge input, are used to map specific geomorphological features or entire landscapes. Current (semi) automated classification techniques are increasingly able to extract morphometric, hydrological, and in the near future also morphogenetic information. As a result, these new opportunities have changed the workflows for geomorphological mapmaking, and their focus have shifted from field-based techniques to using more computer-based techniques: for example, traditional pre-field air-photo based maps are now replaced by maps prepared in a digital mapping environment, and designated field visits using mobile GIS / digital mapping devices now focus on gathering location information and attribute inventories and are strongly time efficient. The resulting 'modern geomorphological maps' are digital collections of geomorphological information layers consisting of georeferenced vector, raster and tabular data which are stored in a digital environment such as a GIS geodatabase, and are easily visualized as e.g. 'birds' eye' views, as animated 3D displays, on virtual globes, or stored as GeoPDF maps in which georeferenced attribute information can be easily exchanged over the internet. Digital geomorphological information layers are increasingly accessed via web-based services distributed through remote servers. Information can be consulted - or even build using remote geoprocessing servers - by the end user. Therefore, it will not only be the geomorphologist anymore, but also the professional end user that dictates the applied use of digital geomorphological information layers.

Route Descriptions by Visually Impaired and Sighted Children from Memory and from Maps.

ERIC Educational Resources Information Center

Edwards, Rachel; Ungar, Simon; Blades, Mark

1998-01-01

This study evaluated descriptions, either from memory or by using a map (print or tactile), of 12 visually impaired and 12 sighted elementary grade children of two routes around their schools. Descriptions from maps were generally poorer than those from memory. Qualitative differences were also found between descriptions of visually impaired and…

[Application Progress of Three-dimensional Laser Scanning Technology in Medical Surface Mapping].

PubMed

Zhang, Yonghong; Hou, He; Han, Yuchuan; Wang, Ning; Zhang, Ying; Zhu, Xianfeng; Wang, Mingshi

2016-04-01

The booming three-dimensional laser scanning technology can efficiently and effectively get spatial three-dimensional coordinates of the detected object surface and reconstruct the image at high speed,high precision and large capacity of information.Non-radiation,non-contact and the ability of visualization make it increasingly popular in three-dimensional surface medical mapping.This paper reviews the applications and developments of three-dimensional laser scanning technology in medical field,especially in stomatology,plastic surgery and orthopedics.Furthermore,the paper also discusses the application prospects in the future as well as the biomedical engineering problems it would encounter with.

D Architectural Videomapping

NASA Astrophysics Data System (ADS)

Catanese, R.

2013-07-01

3D architectural mapping is a video projection technique that can be done with a survey of a chosen building in order to realize a perfect correspondence between its shapes and the images in projection. As a performative kind of audiovisual artifact, the real event of the 3D mapping is a combination of a registered video animation file with a real architecture. This new kind of visual art is becoming very popular and its big audience success testifies new expressive chances in the field of urban design. My case study has been experienced in Pisa for the Luminara feast in 2012.

Use of digital Munsell color space to assist interretation of imaging spectrometer data: Geologic examples from the northern Grapevine Mountains, California and Nevada

NASA Technical Reports Server (NTRS)

Kruse, F. A.; Knepper, D. H., Jr.; Clark, R. N.

1986-01-01

Techniques using Munsell color transformations were developed for reducing 128 channels (or less) of Airborne Imaging Spectrometer (AIS) data to a single color-composite-image suitable for both visual interpretation and digital analysis. Using AIS data acquired in 1984 and 1985, limestone and dolomite roof pendants and sericite-illite and other clay minerals related to alteration were mapped in a quartz monzonite stock in the northern Grapevine Mountains of California and Nevada. Field studies and laboratory spectral measurements verify the mineralogical distributions mapped from the AIS data.

Using the Biodatamation(TM) strategy to learn introductory college biology: Value-added effects on selected students' conceptual understanding and conceptual integration of the processes of photosynthesis and cellular respiration

NASA Astrophysics Data System (ADS)

Reuter, Jewel Jurovich

The purpose of this exploratory research was to study how students learn photosynthesis and cellular respiration and to determine the value added to the student's learning by each of the three technology-scaffolded learning strategy components (animated concept presentations and WebQuest-style activities, data collection, and student-constructed animations) of the BioDatamation(TM) (BDM) Program. BDM learning strategies utilized the Theory of Interacting Visual Fields(TM) (TIVF) (Reuter & Wandersee, 2002a, 2002b; 2003a, 2003b) which holds that meaningful knowledge is hierarchically constructed using the past, present, and future visual fields, with visual metacognitive components that are derived from the principles of Visual Behavior (Jones, 1995), Human Constructivist Theory (Mintzes & Wandersee, 1998a), and Visual Information Design Theory (Tufte, 1990, 1997, 2001). Student alternative conceptions of photosynthesis and cellular respiration were determined by the item analysis of 263,267 Biology Advanced Placement Examinations and were used to develop the BDM instructional strategy and interview questions. The subjects were 24 undergraduate students of high and low biology prior knowledge enrolled in an introductory-level General Biology course at a major research university in the Deep South. Fifteen participants received BDM instruction which included original and innovative learning materials and laboratories in 6 phases; 8 of the 15 participants were the subject of in depth, extended individual analysis. The other 9 participants received traditional, non-BDM instruction. Interviews which included participants' creation of concept maps and visual field diagrams were conducted after each phase. Various content analyses, including Chi's Verbal Analysis and quantitizing/qualitizing were used for data analysis. The total value added to integrative knowledge during BDM instruction with the three visual fields was an average increase of 56% for cellular respiration and 62% increase for photosynthesis knowledge, improved long-term memory of concepts, and enhanced biological literacy to the multidimensional level, as determined by the BSCS literacy model. WebQuest-style activities and data collection provided for animated prior knowledge in the past visual field, and detailed content knowledge construction in the present visual field. During student construction of animated presentations, layering required participants to think by rearranging words and images for improved hierarchical organization of knowledge with real-life applications.

Landslide Inventory Mapping from Bitemporal 10 m SENTINEL-2 Images Using Change Detection Based Markov Random Field

NASA Astrophysics Data System (ADS)

Qin, Y.; Lu, P.; Li, Z.

2018-04-01

Landslide inventory mapping is essential for hazard assessment and mitigation. In most previous studies, landslide mapping was achieved by visual interpretation of aerial photos and remote sensing images. However, such method is labor-intensive and time-consuming, especially over large areas. Although a number of semi-automatic landslide mapping methods have been proposed over the past few years, limitations remain in terms of their applicability over different study areas and data, and there is large room for improvement in terms of the accuracy and automation degree. For these reasons, we developed a change detection-based Markov Random Field (CDMRF) method for landslide inventory mapping. The proposed method mainly includes two steps: 1) change detection-based multi-threshold for training samples generation and 2) MRF for landslide inventory mapping. Compared with the previous methods, the proposed method in this study has three advantages: 1) it combines multiple image difference techniques with multi-threshold method to generate reliable training samples; 2) it takes the spectral characteristics of landslides into account; and 3) it is highly automatic with little parameter tuning. The proposed method was applied for regional landslides mapping from 10 m Sentinel-2 images in Western China. Results corroborated the effectiveness and applicability of the proposed method especially the capability of rapid landslide mapping. Some directions for future research are offered. This study to our knowledge is the first attempt to map landslides from free and medium resolution satellite (i.e., Sentinel-2) images in China.

Areas activated during naturalistic reading comprehension overlap topological visual, auditory, and somatotomotor maps.

PubMed

Sood, Mariam R; Sereno, Martin I

2016-08-01

Cortical mapping techniques using fMRI have been instrumental in identifying the boundaries of topological (neighbor-preserving) maps in early sensory areas. The presence of topological maps beyond early sensory areas raises the possibility that they might play a significant role in other cognitive systems, and that topological mapping might help to delineate areas involved in higher cognitive processes. In this study, we combine surface-based visual, auditory, and somatomotor mapping methods with a naturalistic reading comprehension task in the same group of subjects to provide a qualitative and quantitative assessment of the cortical overlap between sensory-motor maps in all major sensory modalities, and reading processing regions. Our results suggest that cortical activation during naturalistic reading comprehension overlaps more extensively with topological sensory-motor maps than has been heretofore appreciated. Reading activation in regions adjacent to occipital lobe and inferior parietal lobe almost completely overlaps visual maps, whereas a significant portion of frontal activation for reading in dorsolateral and ventral prefrontal cortex overlaps both visual and auditory maps. Even classical language regions in superior temporal cortex are partially overlapped by topological visual and auditory maps. By contrast, the main overlap with somatomotor maps is restricted to a small region on the anterior bank of the central sulcus near the border between the face and hand representations of M-I. Hum Brain Mapp 37:2784-2810, 2016. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

Comparison of event landslide inventories: the Pogliaschina catchment test case, Italy

NASA Astrophysics Data System (ADS)

Mondini, A. C.; Viero, A.; Cavalli, M.; Marchi, L.; Herrera, G.; Guzzetti, F.

2014-07-01

Event landslide inventory maps document the extent of populations of landslides caused by a single natural trigger, such as an earthquake, an intense rainfall event, or a rapid snowmelt event. Event inventory maps are important for landslide susceptibility and hazard modelling, and prove useful to manage residual risk after a landslide-triggering event. Standards for the preparation of event landslide inventory maps are lacking. Traditional methods are based on the visual interpretation of stereoscopic aerial photography, aided by field surveys. New and emerging techniques exploit remotely sensed data and semi-automatic algorithms. We describe the production and comparison of two independent event inventories prepared for the Pogliaschina catchment, Liguria, Northwest Italy. The two inventories show landslides triggered by an intense rainfall event on 25 October 2011, and were prepared through the visual interpretation of digital aerial photographs taken 3 days and 33 days after the event, and by processing a very-high-resolution image taken by the WorldView-2 satellite 4 days after the event. We compare the two inventories qualitatively and quantitatively using established and new metrics, and we discuss reasons for the differences between the two landslide maps. We expect that the results of our work can help in deciding on the most appropriate method to prepare reliable event inventory maps, and outline the advantages and the limitations of the different approaches.

Qualitative and quantitative trait loci conditioning resistance to Puccinia coronata pathotypes NQMG and LGCG in the oat (Avena sativa L.) cultivars Ogle and TAM O-301.

PubMed

Jackson, E W; Obert, D E; Menz, M; Hu, G; Bonman, J M

2008-02-01

Mapping disease resistance loci relies on the type and precision of phenotypic measurements. For crown rust of oat, disease severity is commonly assessed based on visual ratings of infection types (IT) and/or diseased leaf area (DLA) of infected plants in the greenhouse or field. These data can be affected by several variables including; (i) non-uniform disease development in the field; (ii) atypical symptom development in the greenhouse; (iii) the presence of multiple pathogenic races or pathotypes in the field, and (iv) rating bias. To overcome these limitations, we mapped crown rust resistance to single isolates in the Ogle/TAM O-301 (OT) recombinant inbred line (RIL) population using detailed measurements of IT, uredinia length (UL) and relative fungal DNA (FDNA) estimates determined by q-PCR. Measurements were taken on OT parents and recombinant inbred lines (RIL) inoculated with Puccinia coronata pathotypes NQMG and LGCG in separate greenhouse and field tests. Qualitative mapping identified an allele conferred by TAM O-301 on linkage group (LG) OT-11, which produced a bleached fleck phenotype to both NQMG and LGCG. Quantitative mapping identified two major quantitative trait loci (QTL) originating from TAM O-301 on LGs OT-11 and OT-32 which reduced UL and FDNA of both isolates in all experiments. Additionally, minor QTLs that reduced UL and FDNA were detected on LGs OT-15 and OT-8, originating from TAM O-301, and on LG OT-27, originating from Ogle. Detailed assessments of the OT population using two pathotypes in both the greenhouse and field provided comprehensive information to effectively map the genes responsible for crown rust resistance in Ogle and TAM O-301 to NQMG and LGCG.

Using Interactive Data Visualizations for Exploratory Analysis in Undergraduate Genomics Coursework: Field Study Findings and Guidelines

NASA Astrophysics Data System (ADS)

Mirel, Barbara; Kumar, Anuj; Nong, Paige; Su, Gang; Meng, Fan

2016-02-01

Life scientists increasingly use visual analytics to explore large data sets and generate hypotheses. Undergraduate biology majors should be learning these same methods. Yet visual analytics is one of the most underdeveloped areas of undergraduate biology education. This study sought to determine the feasibility of undergraduate biology majors conducting exploratory analysis using the same interactive data visualizations as practicing scientists. We examined 22 upper level undergraduates in a genomics course as they engaged in a case-based inquiry with an interactive heat map. We qualitatively and quantitatively analyzed students' visual analytic behaviors, reasoning and outcomes to identify student performance patterns, commonly shared efficiencies and task completion. We analyzed students' successes and difficulties in applying knowledge and skills relevant to the visual analytics case and related gaps in knowledge and skill to associated tool designs. Findings show that undergraduate engagement in visual analytics is feasible and could be further strengthened through tool usability improvements. We identify these improvements. We speculate, as well, on instructional considerations that our findings suggested may also enhance visual analytics in case-based modules.

Evaluation of angiogram visualization methods for fast and reliable aneurysm diagnosis

NASA Astrophysics Data System (ADS)

Lesar, Žiga; Bohak, Ciril; Marolt, Matija

2015-03-01

In this paper we present the results of an evaluation of different visualization methods for angiogram volumetric data-ray casting, marching cubes, and multi-level partition of unity implicits. There are several options available with ray-casting: isosurface extraction, maximum intensity projection and alpha compositing, each producing fundamentally different results. Different visualization methods are suitable for different needs, so this choice is crucial in diagnosis and decision making processes. We also evaluate visual effects such as ambient occlusion, screen space ambient occlusion, and depth of field. Some visualization methods include transparency, so we address the question of relevancy of this additional visual information. We employ transfer functions to map data values to color and transparency, allowing us to view or hide particular tissues. All the methods presented in this paper were developed using OpenCL, striving for real-time rendering and quality interaction. An evaluation has been conducted to assess the suitability of the visualization methods. Results show superiority of isosurface extraction with ambient occlusion effects. Visual effects may positively or negatively affect perception of depth, motion, and relative positions in space.

Using Interactive Data Visualizations for Exploratory Analysis in Undergraduate Genomics Coursework: Field Study Findings and Guidelines

PubMed Central

Kumar, Anuj; Nong, Paige; Su, Gang; Meng, Fan

2016-01-01

Life scientists increasingly use visual analytics to explore large data sets and generate hypotheses. Undergraduate biology majors should be learning these same methods. Yet visual analytics is one of the most underdeveloped areas of undergraduate biology education. This study sought to determine the feasibility of undergraduate biology majors conducting exploratory analysis using the same interactive data visualizations as practicing scientists. We examined 22 upper level undergraduates in a genomics course as they engaged in a case-based inquiry with an interactive heat map. We qualitatively and quantitatively analyzed students’ visual analytic behaviors, reasoning and outcomes to identify student performance patterns, commonly shared efficiencies and task completion. We analyzed students’ successes and difficulties in applying knowledge and skills relevant to the visual analytics case and related gaps in knowledge and skill to associated tool designs. Findings show that undergraduate engagement in visual analytics is feasible and could be further strengthened through tool usability improvements. We identify these improvements. We speculate, as well, on instructional considerations that our findings suggested may also enhance visual analytics in case-based modules. PMID:26877625

Spatiotemporal mapping of scalp potentials.

PubMed

Fender, D H; Santoro, T P

1977-11-01

Computerized analysis and display techniques are applied to the problem of identifying the origins of visually evoked scalped potentials (VESP's). A new stimulus for VESP work, white noise, is being incorporated in the solution of this problem. VESP's for white-noise stimulation exhibit time domain behavior similar to the classical response for flash stimuli but with certain significant differences. Contour mapping algorithms are used to display the time behavior of equipotential surfaces on the scalp during the VESP. The electrical and geometrical parameters of the head are modeled. Electrical fields closely matching those obtained experimentally are generated on the surface of the model head by optimally selecting the location and strength parameters of one or two dipole current sources contained within the model. Computer graphics are used to display as a movie the actual and model scalp potential field and the parameters of the dipole generators whithin the model head during the time course of the VESP. These techniques are currently used to study retinotopic mapping, fusion, and texture perception in the human.

Enhancement of a Virtual Geology Field Guide of Georgia Initiative Using Gigapan© and ArcGIS Online's Story Map

NASA Astrophysics Data System (ADS)

Mobasher, K.; Turk, H. J.; Witherspoon, W.; Tate, L.; Hoynes, J.

2015-12-01

A GIS geology geodatabase of Georgia was developed using ArcGIS 10.2. The geodatabase for each physiographic provinces of Georgia contains fields designed to store information regarding geologic features. Using ArcGIS online, the virtual field guide is created which provides an interactive learning experience for students to allow in real time photography, description, mapping and sharing their observations with the instructor and peers. Gigapan© facilitates visualizing geologic features at different scales with high resolutions and in their larger surrounding context. The classroom applications of the Gigapan© are limitless when teaching students the entire range of geologic structures from showcasing crystalline structures of minerals to understanding the geological processes responsible for formation of an entire mountain range. The addition of the Story Map enhances the virtual experience when you want to present a geo-located story point narrative featuring images or videos. The virtual field component and supplementary Gigapan© imagery coupled with Story Map added significantly to the detailed realism of virtual field guide further allowing students to more fully understand geological concepts at various scales. These technologies peaked students interest and facilitated their learning and preparation to function more effectively in the geosciences by developing better observations and new skills. These technologies facilitated increased student engagement in the geosciences by sharing, enhancing and transferring lecture information to actual field knowledge and experiences. This enhanced interactive learning experience not only begins to allow students to understand and recognize geologic features in the field but also increased their collaboration, enthusiasm and interest in the discipline. The increased interest and collaboration occurred as students assisted in populating a geologic geodatabase of Georgia.

Simple summation rule for optimal fixation selection in visual search.

PubMed

Najemnik, Jiri; Geisler, Wilson S

2009-06-01

When searching for a known target in a natural texture, practiced humans achieve near-optimal performance compared to a Bayesian ideal searcher constrained with the human map of target detectability across the visual field [Najemnik, J., & Geisler, W. S. (2005). Optimal eye movement strategies in visual search. Nature, 434, 387-391]. To do so, humans must be good at choosing where to fixate during the search [Najemnik, J., & Geisler, W.S. (2008). Eye movement statistics in humans are consistent with an optimal strategy. Journal of Vision, 8(3), 1-14. 4]; however, it seems unlikely that a biological nervous system would implement the computations for the Bayesian ideal fixation selection because of their complexity. Here we derive and test a simple heuristic for optimal fixation selection that appears to be a much better candidate for implementation within a biological nervous system. Specifically, we show that the near-optimal fixation location is the maximum of the current posterior probability distribution for target location after the distribution is filtered by (convolved with) the square of the retinotopic target detectability map. We term the model that uses this strategy the entropy limit minimization (ELM) searcher. We show that when constrained with human-like retinotopic map of target detectability and human search error rates, the ELM searcher performs as well as the Bayesian ideal searcher, and produces fixation statistics similar to human.

Systems and Methods for Data Visualization Using Three-Dimensional Displays

NASA Technical Reports Server (NTRS)

Davidoff, Scott (Inventor); Djorgovski, Stanislav G. (Inventor); Estrada, Vicente (Inventor); Donalek, Ciro (Inventor)

2017-01-01

Data visualization systems and methods for generating 3D visualizations of a multidimensional data space are described. In one embodiment a 3D data visualization application directs a processing system to: load a set of multidimensional data points into a visualization table; create representations of a set of 3D objects corresponding to the set of data points; receive mappings of data dimensions to visualization attributes; determine the visualization attributes of the set of 3D objects based upon the selected mappings of data dimensions to 3D object attributes; update a visibility dimension in the visualization table for each of the plurality of 3D object to reflect the visibility of each 3D object based upon the selected mappings of data dimensions to visualization attributes; and interactively render 3D data visualizations of the 3D objects within the virtual space from viewpoints determined based upon received user input.

Mapping longitudinal scientific progress, collaboration and impact of the Alzheimer's disease neuroimaging initiative.

PubMed

Yao, Xiaohui; Yan, Jingwen; Ginda, Michael; Börner, Katy; Saykin, Andrew J; Shen, Li

2017-01-01

Alzheimer's disease neuroimaging initiative (ADNI) is a landmark imaging and omics study in AD. ADNI research literature has increased substantially over the past decade, which poses challenges for effectively communicating information about the results and impact of ADNI-related studies. In this work, we employed advanced information visualization techniques to perform a comprehensive and systematic mapping of the ADNI scientific growth and impact over a period of 12 years. Citation information of ADNI-related publications from 01/01/2003 to 05/12/2015 were downloaded from the Scopus database. Five fields, including authors, years, affiliations, sources (journals), and keywords, were extracted and preprocessed. Statistical analyses were performed on basic publication data as well as journal and citations information. Science mapping workflows were conducted using the Science of Science (Sci2) Tool to generate geospatial, topical, and collaboration visualizations at the micro (individual) to macro (global) levels such as geospatial layouts of institutional collaboration networks, keyword co-occurrence networks, and author collaboration networks evolving over time. During the studied period, 996 ADNI manuscripts were published across 233 journals and conference proceedings. The number of publications grew linearly from 2008 to 2015, so did the number of involved institutions. ADNI publications received much more citations than typical papers from the same set of journals. Collaborations were visualized at multiple levels, including authors, institutions, and research areas. The evolution of key ADNI research topics was also plotted over the studied period. Both statistical and visualization results demonstrate the increasing attention of ADNI research, strong citation impact of ADNI publications, the expanding collaboration networks among researchers, institutions and ADNI core areas, and the dynamic evolution of ADNI research topics. The visualizations presented here can help improve daily decision making based on a deep understanding of existing patterns and trends using proven and replicable data analysis and visualization methods. They have great potential to provide new insights and actionable knowledge for helping translational research in AD.

Mapping longitudinal scientific progress, collaboration and impact of the Alzheimer’s disease neuroimaging initiative

PubMed Central

Yao, Xiaohui; Yan, Jingwen; Ginda, Michael; Börner, Katy; Saykin, Andrew J.

2017-01-01

Background Alzheimer’s disease neuroimaging initiative (ADNI) is a landmark imaging and omics study in AD. ADNI research literature has increased substantially over the past decade, which poses challenges for effectively communicating information about the results and impact of ADNI-related studies. In this work, we employed advanced information visualization techniques to perform a comprehensive and systematic mapping of the ADNI scientific growth and impact over a period of 12 years. Methods Citation information of ADNI-related publications from 01/01/2003 to 05/12/2015 were downloaded from the Scopus database. Five fields, including authors, years, affiliations, sources (journals), and keywords, were extracted and preprocessed. Statistical analyses were performed on basic publication data as well as journal and citations information. Science mapping workflows were conducted using the Science of Science (Sci2) Tool to generate geospatial, topical, and collaboration visualizations at the micro (individual) to macro (global) levels such as geospatial layouts of institutional collaboration networks, keyword co-occurrence networks, and author collaboration networks evolving over time. Results During the studied period, 996 ADNI manuscripts were published across 233 journals and conference proceedings. The number of publications grew linearly from 2008 to 2015, so did the number of involved institutions. ADNI publications received much more citations than typical papers from the same set of journals. Collaborations were visualized at multiple levels, including authors, institutions, and research areas. The evolution of key ADNI research topics was also plotted over the studied period. Conclusions Both statistical and visualization results demonstrate the increasing attention of ADNI research, strong citation impact of ADNI publications, the expanding collaboration networks among researchers, institutions and ADNI core areas, and the dynamic evolution of ADNI research topics. The visualizations presented here can help improve daily decision making based on a deep understanding of existing patterns and trends using proven and replicable data analysis and visualization methods. They have great potential to provide new insights and actionable knowledge for helping translational research in AD. PMID:29095836

What is an evidence map? A systematic review of published evidence maps and their definitions, methods, and products.

PubMed

Miake-Lye, Isomi M; Hempel, Susanne; Shanman, Roberta; Shekelle, Paul G

2016-02-10

The need for systematic methods for reviewing evidence is continuously increasing. Evidence mapping is one emerging method. There are no authoritative recommendations for what constitutes an evidence map or what methods should be used, and anecdotal evidence suggests heterogeneity in both. Our objectives are to identify published evidence maps and to compare and contrast the presented definitions of evidence mapping, the domains used to classify data in evidence maps, and the form the evidence map takes. We conducted a systematic review of publications that presented results with a process termed "evidence mapping" or included a figure called an "evidence map." We identified publications from searches of ten databases through 8/21/2015, reference mining, and consulting topic experts. We abstracted the research question, the unit of analysis, the search methods and search period covered, and the country of origin. Data were narratively synthesized. Thirty-nine publications met inclusion criteria. Published evidence maps varied in their definition and the form of the evidence map. Of the 31 definitions provided, 67 % described the purpose as identification of gaps and 58 % referenced a stakeholder engagement process or user-friendly product. All evidence maps explicitly used a systematic approach to evidence synthesis. Twenty-six publications referred to a figure or table explicitly called an "evidence map," eight referred to an online database as the evidence map, and five stated they used a mapping methodology but did not present a visual depiction of the evidence. The principal conclusion of our evaluation of studies that call themselves "evidence maps" is that the implied definition of what constitutes an evidence map is a systematic search of a broad field to identify gaps in knowledge and/or future research needs that presents results in a user-friendly format, often a visual figure or graph, or a searchable database. Foundational work is needed to better standardize the methods and products of an evidence map so that researchers and policymakers will know what to expect of this new type of evidence review. Although an a priori protocol was developed, no registration was completed; this review did not fit the PROSPERO format.

Musician Map: visualizing music collaborations over time

NASA Astrophysics Data System (ADS)

Yim, Ji-Dong; Shaw, Chris D.; Bartram, Lyn

2009-01-01

In this paper we introduce Musician Map, a web-based interactive tool for visualizing relationships among popular musicians who have released recordings since 1950. Musician Map accepts search terms from the user, and in turn uses these terms to retrieve data from MusicBrainz.org and AudioScrobbler.net, and visualizes the results. Musician Map visualizes relationships of various kinds between music groups and individual musicians, such as band membership, musical collaborations, and linkage to other artists that are generally regarded as being similar in musical style. These relationships are plotted between artists using a new timeline-based visualization where a node in a traditional node-link diagram has been transformed into a Timeline-Node, which allows the visualization of an evolving entity over time, such as the membership in a band. This allows the user to pursue social trend queries such as "Do Hip-Hop artists collaborate differently than Rock artists".

Sensory experience modifies feature map relationships in visual cortex

PubMed Central

Cloherty, Shaun L; Hughes, Nicholas J; Hietanen, Markus A; Bhagavatula, Partha S

2016-01-01

The extent to which brain structure is influenced by sensory input during development is a critical but controversial question. A paradigmatic system for studying this is the mammalian visual cortex. Maps of orientation preference (OP) and ocular dominance (OD) in the primary visual cortex of ferrets, cats and monkeys can be individually changed by altered visual input. However, the spatial relationship between OP and OD maps has appeared immutable. Using a computational model we predicted that biasing the visual input to orthogonal orientation in the two eyes should cause a shift of OP pinwheels towards the border of OD columns. We then confirmed this prediction by rearing cats wearing orthogonally oriented cylindrical lenses over each eye. Thus, the spatial relationship between OP and OD maps can be modified by visual experience, revealing a previously unknown degree of brain plasticity in response to sensory input. DOI: http://dx.doi.org/10.7554/eLife.13911.001 PMID:27310531

The visual white matter: The application of diffusion MRI and fiber tractography to vision science

PubMed Central

Rokem, Ariel; Takemura, Hiromasa; Bock, Andrew S.; Scherf, K. Suzanne; Behrmann, Marlene; Wandell, Brian A.; Fine, Ione; Bridge, Holly; Pestilli, Franco

2017-01-01

Visual neuroscience has traditionally focused much of its attention on understanding the response properties of single neurons or neuronal ensembles. The visual white matter and the long-range neuronal connections it supports are fundamental in establishing such neuronal response properties and visual function. This review article provides an introduction to measurements and methods to study the human visual white matter using diffusion MRI. These methods allow us to measure the microstructural and macrostructural properties of the white matter in living human individuals; they allow us to trace long-range connections between neurons in different parts of the visual system and to measure the biophysical properties of these connections. We also review a range of findings from recent studies on connections between different visual field maps, the effects of visual impairment on the white matter, and the properties underlying networks that process visual information supporting visual face recognition. Finally, we discuss a few promising directions for future studies. These include new methods for analysis of MRI data, open datasets that are becoming available to study brain connectivity and white matter properties, and open source software for the analysis of these data. PMID:28196374

Using Saliency-Weighted Disparity Statistics for Objective Visual Comfort Assessment of Stereoscopic Images

NASA Astrophysics Data System (ADS)

Zhang, Wenlan; Luo, Ting; Jiang, Gangyi; Jiang, Qiuping; Ying, Hongwei; Lu, Jing

2016-06-01

Visual comfort assessment (VCA) for stereoscopic images is a particularly significant yet challenging task in 3D quality of experience research field. Although the subjective assessment given by human observers is known as the most reliable way to evaluate the experienced visual discomfort, it is time-consuming and non-systematic. Therefore, it is of great importance to develop objective VCA approaches that can faithfully predict the degree of visual discomfort as human beings do. In this paper, a novel two-stage objective VCA framework is proposed. The main contribution of this study is that the important visual attention mechanism of human visual system is incorporated for visual comfort-aware feature extraction. Specifically, in the first stage, we first construct an adaptive 3D visual saliency detection model to derive saliency map of a stereoscopic image, and then a set of saliency-weighted disparity statistics are computed and combined to form a single feature vector to represent a stereoscopic image in terms of visual comfort. In the second stage, a high dimensional feature vector is fused into a single visual comfort score by performing random forest algorithm. Experimental results on two benchmark databases confirm the superior performance of the proposed approach.

Testing geoscience data visualization systems for geological mapping and training

NASA Astrophysics Data System (ADS)

Head, J. W.; Huffman, J. N.; Forsberg, A. S.; Hurwitz, D. M.; Basilevsky, A. T.; Ivanov, M. A.; Dickson, J. L.; Senthil Kumar, P.

2008-09-01

Traditional methods of planetary geological mapping have relied on photographic hard copy and light-table tracing and mapping. In the last several decades this has given way to the availability and analysis of multiple digital data sets, and programs and platforms that permit the viewing and manipulation of multiple annotated layers of relevant information. This has revolutionized the ability to incorporate important new data into the planetary mapping process at all scales. Information on these developments and approaches can be obtained at http://astrogeology.usgs. gov/ Technology/. The processes is aided by Geographic Information Systems (GIS) (see http://astrogeology. usgs.gov/Technology/) and excellent analysis packages (such as ArcGIS) that permit co-registration, rapid viewing, and analysis of multiple data sets on desktop displays (see http://astrogeology.usgs.gov/Projects/ webgis/). We are currently investigating new technological developments in computer visualization and analysis in order to assess their importance and utility in planetary geological analysis and mapping. Last year we reported on the range of technologies available and on our application of these to various problems in planetary mapping. In this contribution we focus on the application of these techniques and tools to Venus geological mapping at the 1:5M quadrangle scale. In our current Venus mapping projects we have utilized and tested the various platforms to understand their capabilities and assess their usefulness in defining units, establishing stratigraphic relationships, mapping structures, reaching consensus on interpretations and producing map products. We are specifically assessing how computer visualization display qualities (e.g., level of immersion, stereoscopic vs. monoscopic viewing, field of view, large vs. small display size, etc.) influence performance on scientific analysis and geological mapping. We have been exploring four different environments: 1) conventional desktops (DT), 2) semi-immersive Fishtank VR (FT) (i.e., a conventional desktop with head-tracked stereo and 6DOF input), 3) tiled wall displays (TW), and 4) fully immersive virtual reality (IVR) (e.g., "Cave Automatic Virtual Environment", or Cave system). Formal studies demonstrate that fully immersive Cave environments are superior to desktop systems for many tasks. There is still much to learn and understand, however, about how the varying degrees of immersive displays affect task performance. For example, in using a 1280x1024 desktop monitor to explore an image, the mapper wastes a lot of time in image zooming/panning to balance the analysis-driven need for both detail as well as context. Therefore, we have spent a considerable amount of time exploring higher-resolution media, such as an IBM Bertha display 3840x2400 or a tiled wall with multiple projectors. We have found through over a year of weekly meetings and assessment that they definitely improve the efficiency of analysis and mapping. Here we outline briefly the nature of the major systems and our initial assessment of these in 1:5M Scale NASA-USGS Venus Geological Mapping Program (http://astrogeology.usgs. gov/Projects/PlanetaryMapping/MapStatus/VenusStatus/V enus_Status.html). 1. Immersive Virtual Reality (Cave): ADVISER System Description: Our Cave system is an 8'x8'x8' cube with four projection surfaces (three walls and the floor). Four linux machines (identical in performance to the desktop machine) provide data for the Cave. Users utilize a handheld 3D tracked input device to navigate. Our 3D input device has a joystick and is simple to use. To navigate, the user simply points in the direction he/she wants to fly and pushes the joystick forward or backward to move relative to that direction. The user can push the joystick to the left and right to rotate his/her position in the virtual world. A collision detection algorithm is used to prevent the user from going underneath the surface. We have developed ADVISER (ADvanced VIsualization for Solar system Exploration) [1,2] as a tool for taking planetary geologists virtually "into the field" in the IVR Cave environment in support of several scientific themes and have assessed its application to geological mapping of Venus. ADVISER aims to create a field experience by integrating multiple data sources and presenting them as a unified environment to the scientist. Additionally, we have developed a virtual field kit, tailored to supporting research tasks dictated by scientific and mapping themes. Technically, ADVISER renders high-resolution topographic and image datasets (8192x8192 samples) in stereo at interactive frame-rates (25+ frames-per-second). The system is based on a state-of-the-art terrain rendering system and is highly interactive; for example, vertical exaggeration, lighting geometry, image contrast, and contour lines can be modified by the user in real time. High-resolution image data can be overlaid on the terrain and other data can be rendered in this context. A detailed description and case studies of ADVISER are available.

Situational Awareness Applied to Geology Field Mapping using Integration of Semantic Data and Visualization Techniques

NASA Astrophysics Data System (ADS)

Houser, P. I. Q.

2017-12-01

21st century earth science is data-intensive, characterized by heterogeneous, sometimes voluminous collections representing phenomena at different scales collected for different purposes and managed in disparate ways. However, much of the earth's surface still requires boots-on-the-ground, in-person fieldwork in order to detect the subtle variations from which humans can infer complex structures and patterns. Nevertheless, field experiences can and should be enabled and enhanced by a variety of emerging technologies. The goal of the proposed research project is to pilot test emerging data integration, semantic and visualization technologies for evaluation of their potential usefulness in the field sciences, particularly in the context of field geology. The proposed project will investigate new techniques for data management and integration enabled by semantic web technologies, along with new techniques for augmented reality that can operate on such integrated data to enable in situ visualization in the field. The research objectives include: Develop new technical infrastructure that applies target technologies to field geology; Test, evaluate, and assess the technical infrastructure in a pilot field site; Evaluate the capabilities of the systems for supporting and augmenting field science; and Assess the generality of the system for implementation in new and different types of field sites. Our hypothesis is that these technologies will enable what we call "field science situational awareness" - a cognitive state formerly attained only through long experience in the field - that is highly desirable but difficult to achieve in time- and resource-limited settings. Expected outcomes include elucidation of how, and in what ways, these technologies are beneficial in the field; enumeration of the steps and requirements to implement these systems; and cost/benefit analyses that evaluate under what conditions the investments of time and resources are advisable to construct such system.

Integrated terrain mapping with digital Landsat images in Queensland, Australia

USGS Publications Warehouse

Robinove, Charles Joseph

1979-01-01

Mapping with Landsat images usually is done by selecting single types of features, such as soils, vegetation, or rocks, and creating visually interpreted or digitally classified maps of each feature. Individual maps can then be overlaid on or combined with other maps to characterize the terrain. Integrated terrain mapping combines several terrain features into each map unit which, in many cases, is more directly related to uses of the land and to methods of land management than the single features alone. Terrain brightness, as measured by the multispectral scanners in Landsat 1 and 2, represents an integration of reflectance from the terrain features within the scanner's instantaneous field of view and is therefore more correlatable with integrated terrain units than with differentiated ones, such as rocks, soils, and vegetation. A test of the feasibilty of the technique of mapping integrated terrain units was conducted in a part of southwestern Queensland, Australia, in cooperation with scientists of the Queensland Department of Primary Industries. The primary purpose was to test the use of digital classification techniques to create a 'land systems map' usable for grazing land management. A recently published map of 'land systems' in the area (made by aerial photograph interpretation and ground surveys), which are integrated terrain units composed of vegetation, soil, topography, and geomorphic features, was used as a basis for comparison with digitally classified Landsat multispectral images. The land systems, in turn, each have a specific grazing capacity for cattle (expressed in beasts per km 2 ) which is estimated following analysis of both research results and property carrying capacities. Landsat images, in computer-compatible tape form, were first contrast-stretched to increase their visual interpretability, and digitally classified by the parallelepiped method into distinct spectral classes to determine their correspondence to the land systems classes and to areally smaller, but readily recognizable, 'land units.' Many land systems appeared as distinct spectral classes or as acceptably homogeneous combinations of several spectral classes. The digitally classified map corresponded to the general geographic patterns of many of the land systems. Statistical correlation of the digitally classified map and the published map was not possible because the published map showed only land systems whereas the digitally classified map showed some land units as well as systems. The general correspondence of spectral classes to the integrated terrain units means that the digital mapping of the units may precede fieldwork and act as a guide to field sampling and detailed terrain unit description as well as measuring of the location, area, and extent of each unit. Extension of the Landsat mapping and classification technique to other arid and semi-arid regions of the world may be feasible.

LOD map--A visual interface for navigating multiresolution volume visualization.

PubMed

Wang, Chaoli; Shen, Han-Wei

2006-01-01

In multiresolution volume visualization, a visual representation of level-of-detail (LOD) quality is important for us to examine, compare, and validate different LOD selection algorithms. While traditional methods rely on ultimate images for quality measurement, we introduce the LOD map--an alternative representation of LOD quality and a visual interface for navigating multiresolution data exploration. Our measure for LOD quality is based on the formulation of entropy from information theory. The measure takes into account the distortion and contribution of multiresolution data blocks. A LOD map is generated through the mapping of key LOD ingredients to a treemap representation. The ordered treemap layout is used for relative stable update of the LOD map when the view or LOD changes. This visual interface not only indicates the quality of LODs in an intuitive way, but also provides immediate suggestions for possible LOD improvement through visually-striking features. It also allows us to compare different views and perform rendering budget control. A set of interactive techniques is proposed to make the LOD adjustment a simple and easy task. We demonstrate the effectiveness and efficiency of our approach on large scientific and medical data sets.

Semantics by analogy for illustrative volume visualization☆

PubMed Central

Gerl, Moritz; Rautek, Peter; Isenberg, Tobias; Gröller, Eduard

2012-01-01

We present an interactive graphical approach for the explicit specification of semantics for volume visualization. This explicit and graphical specification of semantics for volumetric features allows us to visually assign meaning to both input and output parameters of the visualization mapping. This is in contrast to the implicit way of specifying semantics using transfer functions. In particular, we demonstrate how to realize a dynamic specification of semantics which allows to flexibly explore a wide range of mappings. Our approach is based on three concepts. First, we use semantic shader augmentation to automatically add rule-based rendering functionality to static visualization mappings in a shader program, while preserving the visual abstraction that the initial shader encodes. With this technique we extend recent developments that define a mapping between data attributes and visual attributes with rules, which are evaluated using fuzzy logic. Second, we let users define the semantics by analogy through brushing on renderings of the data attributes of interest. Third, the rules are specified graphically in an interface that provides visual clues for potential modifications. Together, the presented methods offer a high degree of freedom in the specification and exploration of rule-based mappings and avoid the limitations of a linguistic rule formulation. PMID:23576827

Coherent Doppler lidar for measurements of wind fields

NASA Technical Reports Server (NTRS)

Menzies, Robert T.; Hardesty, R. Michael

1989-01-01

The signal-processing techniques for obtaining the velocity estimates and the fundamental factors that influence coherent lidar performance are considered. The similarities and distinctions between Doppler lidar and Doppler radars are discussed. The capability of coherent Doppler lidars for mapping wind fields over selected regions in the lower atmosphere and greatly enhancing the capability to visualize flow patterns in real time is discussed, and examples are given. Salient features of a concept for an earth-orbiting Doppler lidar to be launched in the late 1990s are examined.

An embodied perspective on expertise in solving the problem of making a geologic map

NASA Astrophysics Data System (ADS)

Callahan, Caitlin Norah

The task of constructing a geologic map is a cognitively and physically demanding field-based problem. The map produced is understood to be an individual's two-dimensional interpretation or mental model of the three-dimensional underlying geology. A popular view within the geoscience community is that teaching students how to make a geologic map is valuable for preparing them to deal with disparate and incomplete data sets, for helping them develop problem-solving skills, and for acquiring expertise in geology. Few previous studies have focused specifically on expertise in geologic mapping. Drawing from literature related to expertise, to problem solving, and to mental models, two overarching research questions were identified: How do geologists of different levels of expertise constrain and solve an ill-structured problem such as making a geologic map? How do geologists address the uncertainties inherent to the processes and interpretations involved in solving a geologic mapping problem? These questions were answered using a methodology that captured the physical actions, expressed thoughts, and navigation paths of geologists as they made a geologic map. Eight geologists, from novice to expert, wore a head-mounted video camera with an attached microphone to record those actions and thoughts, creating "video logs" while in the field. The video logs were also time-stamped, which allowed the visual and audio data to be synchronized with the GPS data that tracked participants' movements in the field. Analysis of the video logs yielded evidence that all eight participants expressed thoughts that reflected the process of becoming mentally situated in the mapping task (e.g. relating between distance on a map and distance in three-dimensional space); the prominence of several of these early thoughts waned in the expressed thoughts later in the day. All participants collected several types of data while in the field; novices, however, did so more continuously throughout the day whereas the experts collected more of their data earlier in the day. Experts and novices also differed in that experts focused more on evaluating certainty in their interpretations; the novices focused more on evaluating the certainty of their observations and sense of location.

An Integrated Tone Mapping for High Dynamic Range Image Visualization

NASA Astrophysics Data System (ADS)

Liang, Lei; Pan, Jeng-Shyang; Zhuang, Yongjun

2018-01-01

There are two type tone mapping operators for high dynamic range (HDR) image visualization. HDR image mapped by perceptual operators have strong sense of reality, but will lose local details. Empirical operators can maximize local detail information of HDR image, but realism is not strong. A common tone mapping operator suitable for all applications is not available. This paper proposes a novel integrated tone mapping framework which can achieve conversion between empirical operators and perceptual operators. In this framework, the empirical operator is rendered based on improved saliency map, which simulates the visual attention mechanism of the human eye to the natural scene. The results of objective evaluation prove the effectiveness of the proposed solution.

Choosing colors for map display icons using models of visual search.

PubMed

Shive, Joshua; Francis, Gregory

2013-04-01

We show how to choose colors for icons on maps to minimize search time using predictions of a model of visual search. The model analyzes digital images of a search target (an icon on a map) and a search display (the map containing the icon) and predicts search time as a function of target-distractor color distinctiveness and target eccentricity. We parameterized the model using data from a visual search task and performed a series of optimization tasks to test the model's ability to choose colors for icons to minimize search time across icons. Map display designs made by this procedure were tested experimentally. In a follow-up experiment, we examined the model's flexibility to assign colors in novel search situations. The model fits human performance, performs well on the optimization tasks, and can choose colors for icons on maps with novel stimuli to minimize search time without requiring additional model parameter fitting. Models of visual search can suggest color choices that produce search time reductions for display icons. Designers should consider constructing visual search models as a low-cost method of evaluating color assignments.

Field camp: Using traditional methods to train the next generation of petroleum geologists

USGS Publications Warehouse

Puckette, J.O.; Suneson, N.H.

2009-01-01

The summer field camp experience provides many students with their best opportunity to learn the scientific process by making observations and collecting, recording, evaluating, and interpreting geologic data. Field school projects enhance student professional development by requiring cooperation and interpersonal interaction, report writing to communicate interpretations, and the development of project management skills to achieve a common goal. The field school setting provides students with the opportunity to observe geologic features and their spatial distribution, size, and shape that will impact the student's future careers as geoscientists. The Les Huston Geology Field Camp (a.k.a. Oklahoma Geology Camp) near Ca??on City, Colorado, focuses on time-tested traditional methods of geological mapping and fieldwork to accomplish these goals. The curriculum consists of an introduction to field techniques (pacing, orienteering, measuring strike and dip, and using a Jacob's staff), sketching outcrops, section measuring (one illustrating facies changes), three mapping exercises (of increasing complexity), and a field geophysics project. Accurate rock and contact descriptions are emphasized, and attitudes and contacts are mapped in the field. Mapping is done on topographic maps at 1:12,000 and 1:6000 scales; air photos are provided. Global positioning system (GPS)-assisted mapping is allowed, but we insist that locations be recorded in the field and confirmed using visual observations. The course includes field trips to the Cripple Creek and Leadville mining districts, Floris-sant/Guffey volcano area, Pikes Peak batholith, and the Denver Basin. Each field trip is designed to emphasize aspects of geology that are not stressed in the field exercises. Students are strongly encouraged to accurately describe geologic features and gather evidence to support their interpretations of the geologic history. Concise reports are a part of each major exercise. Students are grouped into teams to (1) introduce the team concept and develop interpersonal skills that are fundamental components of many professions, (2) ensure safety, and (3) mix students with varying academic backgrounds and physical strengths. This approach has advantages and disadvantages. Students with academic strengths in specific areas assist those with less experience, thereby becoming engaged in the teaching process. However, some students contribute less to fi nal map projects than others, and assigning grades to individual team members can be diffi cult. The greatest challenges we face involve group dynamics and student personalities. We continue to believe that traditional fi eld methods, aided by (but not relying upon) new technologies, are the key to constructing and/or interpreting geologic maps. The requirement that students document fi eld evidence using careful observations teaches skills that will be benefi cial throughout their professional careers. ??2009 The Geological Society of America. All rights reserved.

New Perspectives on Active Tectonics: Observing Fault Motion, Mapping Earthquake Strain Fields, and Visualizing Seismic Events in Multiple Dimensions Using Satellite Imagery and Geophysical Data Base

NASA Technical Reports Server (NTRS)

Crippen, R.; Blom, R.

1994-01-01

By rapidly alternating displays of SPOT satellite images acquired on 27 July 1991 and 25 July 1992 we are able to see spatial details of terrain movements along fault breaks associated with the 28 June 1992 Landers, California earthquake that are virtually undetectable by any other means.

Medical technology advances from space research.

NASA Technical Reports Server (NTRS)

Pool, S. L.

1971-01-01

NASA-sponsored medical R & D programs for space applications are reviewed with particular attention to the benefits of these programs to earthbound medical services and to the general public. Notable among the results of these NASA programs is an integrated medical laboratory equipped with numerous advanced systems such as digital biotelemetry and automatic visual field mapping systems, sponge electrode caps for electroencephalograms, and sophisticated respiratory analysis equipment.

Medical technology advances from space research

NASA Technical Reports Server (NTRS)

Pool, S. L.

1972-01-01

Details of medical research and development programs, particularly an integrated medical laboratory, as derived from space technology are given. The program covers digital biotelemetry systems, automatic visual field mapping equipment, sponge electrode caps for clinical electroencephalograms, and advanced respiratory analysis equipment. The possibility of using the medical laboratory in ground based remote areas and regional health care facilities, as well as long duration space missions is discussed.

The second visual area in the marmoset monkey: visuotopic organisation, magnification factors, architectonical boundaries, and modularity.

PubMed

Rosa, M G; Fritsches, K A; Elston, G N

1997-11-03

The organisation of the second visual area (V2) in marmoset monkeys was studied by means of extracellular recordings of responses to visual stimulation and examination of myelin- and cytochrome oxidase-stained sections. Area V2 forms a continuous cortical belt of variable width (1-2 mm adjacent to the foveal representation of V1, and 3-3.5 mm near the midline and on the tentorial surface) bordering V1 on the lateral, dorsal, medial, and tentorial surfaces of the occipital lobe. The total surface area of V2 is approximately 100 mm2, or about 50% of the surface area of V1 in the same individuals. In each hemisphere, the receptive fields of V2 neurones cover the entire contralateral visual hemifield, forming an ordered visuotopic representation. As in other simians, the dorsal and ventral halves of V2 represent the lower and upper contralateral quadrants, respectively, with little invasion of the ipsilateral hemifield. The representation of the vertical meridian forms the caudal border of V2, with V1, whereas a field discontinuity approximately coincident with the horizontal meridian forms the rostral border of V2, with other visually responsive areas. The bridge of cortex connecting dorsal and ventral V2 contains neurones with receptive fields centred within 1 degree of the centre of the fovea. The visuotopy, size, shape and location of V2 show little variation among individuals. Analysis of cortical magnification factor (CMF) revealed that the V2 map of the visual field is highly anisotropic: for any given eccentricity, the CMF is approximately twice as large in the dimension parallel to the V1/V2 border as it is perpendicular to this border. Moreover, comparison of V2 and V1 in the same individuals demonstrated that the representation of the central visual field is emphasised in V2, relative to V1. Approximately half of the surface area of V2 is dedicated to the representation of the central 5 degrees of the visual field. Calculations based on the CMF, receptive field scatter, and receptive field size revealed that the point-image size measured parallel to the V1/V2 border (2-3 mm) equals the width of a full cycle of cytochrome oxidase stripes in V2, suggesting a close correspondence between physiological and anatomical estimates of the dimensions of modular components in this area.

Analyzing the texture changes in the quantitative phase maps of adipocytes

NASA Astrophysics Data System (ADS)

Roitshtain, Darina; Sharabani-Yosef, Orna; Gefen, Amit; Shaked, Natan T.

2016-03-01

We present a new analysis tool for studying texture changes in the quantitative phase maps of live cells acquired by wide-field interferometry. The sensitivity of wide-field interferometry systems to small changes in refractive index enables visualizing cells and inner cell organelles without the using fluorescent dyes or other cell-invasive approaches, which may affect the measurement and require external labeling. Our label-free texture-analysis tool is based directly on the optical path delay profile of the sample and does not necessitate decoupling refractive index and thickness in the cell quantitative phase profile; thus, relevant parameters can be calculated using a single-frame acquisition. Our experimental system includes low-coherence wide-field interferometer, combined with simultaneous florescence microscopy system for validation. We used this system and analysis tool for studying lipid droplets formation in adipocytes. The latter demonstration is relevant for various cellular functions such as lipid metabolism, protein storage and degradation to viral replication. These processes are functionally linked to several physiological and pathological conditions, including obesity and metabolic diseases. Quantification of these biological phenomena based on the texture changes in the cell phase map has a potential as a new cellular diagnosis tool.

Detection, eye–hand coordination and virtual mobility performance in simulated vision for a cortical visual prosthesis device

PubMed Central

Srivastava, Nishant R; Troyk, Philip R; Dagnelie, Gislin

2014-01-01

In order to assess visual performance using a future cortical prosthesis device, the ability of normally sighted and low vision subjects to adapt to a dotted ‘phosphene’ image was studied. Similar studies have been conduced in the past and adaptation to phosphene maps has been shown but the phosphene maps used have been square or hexagonal in pattern. The phosphene map implemented for this testing is what is expected from a cortical implantation of the arrays of intracortical electrodes, generating multiple phosphenes. The dotted image created depends upon the surgical location of electrodes decided for implantation and the expected cortical response. The subjects under tests were required to perform tasks requiring visual inspection, eye–hand coordination and way finding. The subjects did not have any tactile feedback and the visual information provided was live dotted images captured by a camera on a head-mounted low vision enhancing system and processed through a filter generating images similar to the images we expect the blind persons to perceive. The images were locked to the subject’s gaze by means of video-based pupil tracking. In the detection and visual inspection task, the subject scanned a modified checkerboard and counted the number of square white fields on a square checkerboard, in the eye–hand coordination task, the subject placed black checkers on the white fields of the checkerboard, and in the way-finding task, the subjects maneuvered themselves through a virtual maze using a game controller. The accuracy and the time to complete the task were used as the measured outcome. As per the surgical studies by this research group, it might be possible to implant up to 650 electrodes; hence, 650 dots were used to create images and performance studied under 0% dropout (650 dots), 25% dropout (488 dots) and 50% dropout (325 dots) conditions. It was observed that all the subjects under test were able to learn the given tasks and showed improvement in performance with practice even with a dropout condition of 50% (325 dots). Hence, if a cortical prosthesis is implanted in human subjects, they might be able to perform similar tasks and with practice should be able to adapt to dotted images even with a low resolution of 325 dots of phosphene. PMID:19458397

Mapping paddy rice distribution using multi-temporal Landsat imagery in the Sanjiang Plain, northeast China

PubMed Central

XIAO, Xiangming; DONG, Jinwei; QIN, Yuanwei; WANG, Zongming

2016-01-01

Information of paddy rice distribution is essential for food production and methane emission calculation. Phenology-based algorithms have been utilized in the mapping of paddy rice fields by identifying the unique flooding and seedling transplanting phases using multi-temporal moderate resolution (500 m to 1 km) images. In this study, we developed simple algorithms to identify paddy rice at a fine resolution at the regional scale using multi-temporal Landsat imagery. Sixteen Landsat images from 2010–2012 were used to generate the 30 m paddy rice map in the Sanjiang Plain, northeast China—one of the major paddy rice cultivation regions in China. Three vegetation indices, Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), and Land Surface Water Index (LSWI), were used to identify rice fields during the flooding/transplanting and ripening phases. The user and producer accuracies of paddy rice on the resultant Landsat-based paddy rice map were 90% and 94%, respectively. The Landsat-based paddy rice map was an improvement over the paddy rice layer on the National Land Cover Dataset, which was generated through visual interpretation and digitalization on the fine-resolution images. The agricultural census data substantially underreported paddy rice area, raising serious concern about its use for studies on food security. PMID:27695637

Visual attention in egocentric field-of-view using RGB-D data

NASA Astrophysics Data System (ADS)

Olesova, Veronika; Benesova, Wanda; Polatsek, Patrik

2017-03-01

Most of the existing solutions predicting visual attention focus solely on referenced 2D images and disregard any depth information. This aspect has always represented a weak point since the depth is an inseparable part of the biological vision. This paper presents a novel method of saliency map generation based on results of our experiments with egocentric visual attention and investigation of its correlation with perceived depth. We propose a model to predict the attention using superpixel representation with an assumption that contrast objects are usually salient and have a sparser spatial distribution of superpixels than their background. To incorporate depth information into this model, we propose three different depth techniques. The evaluation is done on our new RGB-D dataset created by SMI eye-tracker glasses and KinectV2 device.

The mapping of eccentricity and meridional angle onto orthogonal axes in the primary visual cortex: an activity-dependent developmental model.

PubMed

Philips, Ryan T; Chakravarthy, V Srinivasa

2015-01-01

Primate vision research has shown that in the retinotopic map of the primary visual cortex, eccentricity and meridional angle are mapped onto two orthogonal axes: whereas the eccentricity is mapped onto the nasotemporal axis, the meridional angle is mapped onto the dorsoventral axis. Theoretically such a map has been approximated by a complex log map. Neural models with correlational learning have explained the development of other visual maps like orientation maps and ocular-dominance maps. In this paper it is demonstrated that activity based mechanisms can drive a self-organizing map (SOM) into such a configuration that dilations and rotations of a particular image (in this case a rectangular bar) are mapped onto orthogonal axes. We further demonstrate using the Laterally Interconnected Synergetically Self Organizing Map (LISSOM) model, with an appropriate boundary and realistic initial conditions, that a retinotopic map which maps eccentricity and meridional angle to the horizontal and vertical axes respectively can be developed. This developed map bears a strong resemblance to the complex log map. We also simulated lesion studies which indicate that the lateral excitatory connections play a crucial role in development of the retinotopic map.

GlastCam: A Telemetry-Driven Spacecraft Visualization Tool

NASA Technical Reports Server (NTRS)

Stoneking, Eric T.; Tsai, Dean

2009-01-01

Developed for the GLAST project, which is now the Fermi Gamma-ray Space Telescope, GlastCam software ingests telemetry from the Integrated Test and Operations System (ITOS) and generates four graphical displays of geometric properties in real time, allowing visual assessment of the attitude, configuration, position, and various cross-checks. Four windows are displayed: a "cam" window shows a 3D view of the satellite; a second window shows the standard position plot of the satellite on a Mercator map of the Earth; a third window displays star tracker fields of view, showing which stars are visible from the spacecraft in order to verify star tracking; and the fourth window depicts

Influences of Long-Term Memory-Guided Attention and Stimulus-Guided Attention on Visuospatial Representations within Human Intraparietal Sulcus.

PubMed

Rosen, Maya L; Stern, Chantal E; Michalka, Samantha W; Devaney, Kathryn J; Somers, David C

2015-08-12

Human parietal cortex plays a central role in encoding visuospatial information and multiple visual maps exist within the intraparietal sulcus (IPS), with each hemisphere symmetrically representing contralateral visual space. Two forms of hemispheric asymmetries have been identified in parietal cortex ventrolateral to visuotopic IPS. Key attentional processes are localized to right lateral parietal cortex in the temporoparietal junction and long-term memory (LTM) retrieval processes are localized to the left lateral parietal cortex in the angular gyrus. Here, using fMRI, we investigate how spatial representations of visuotopic IPS are influenced by stimulus-guided visuospatial attention and by LTM-guided visuospatial attention. We replicate prior findings that a hemispheric asymmetry emerges under stimulus-guided attention: in the right hemisphere (RH), visual maps IPS0, IPS1, and IPS2 code attentional targets across the visual field; in the left hemisphere (LH), IPS0-2 codes primarily contralateral targets. We report the novel finding that, under LTM-guided attention, both RH and LH IPS0-2 exhibit bilateral responses and hemispheric symmetry re-emerges. Therefore, we demonstrate that both hemispheres of IPS0-2 are independently capable of dynamically changing spatial coding properties as attentional task demands change. These findings have important implications for understanding visuospatial and memory-retrieval deficits in patients with parietal lobe damage. The human parietal lobe contains multiple maps of the external world that spatially guide perception, action, and cognition. Maps in each cerebral hemisphere code information from the opposite side of space, not from the same side, and the two hemispheres are symmetric. Paradoxically, damage to specific parietal regions that lack spatial maps can cause patients to ignore half of space (hemispatial neglect syndrome), but only for right (not left) hemisphere damage. Conversely, the left parietal cortex has been linked to retrieval of vivid memories regardless of space. Here, we investigate possible underlying mechanisms in healthy individuals. We demonstrate two forms of dynamic changes in parietal spatial representations: an asymmetric one for stimulus-guided attention and a symmetric one for long-term memory-guided attention. Copyright © 2015 the authors 0270-6474/15/3511358-06$15.00/0.

How to use concept mapping to identify barriers and facilitators of an electronic quality improvement intervention.

PubMed

van Engen-Verheul, Mariëtte; Peek, Niels; Vromen, Tom; Jaspers, Monique; de Keizer, Nicolette

2015-01-01

Systematic quality improvement (QI) interventions are increasingly used to change complex health care systems. Results of randomized clinical trials can provide quantitative evidence whether QI interventions were effective but they do not teach us why and how QI was (not) achieved. Qualitative research methods can answer these questions but typically involve only a small group of respondents against high resources. Concept mapping methodology overcomes these drawbacks by integrating results from qualitative group sessions with multivariate statistical analysis to represent ideas of diverse stakeholders visually on maps in an efficient way. This paper aims to describe how to use concept mapping to qualitatively gain insight into barriers and facilitators of an electronic QI intervention and presents experiences with the method from an ongoing case study to evaluate a QI system in the field of cardiac rehabilitation in the Netherlands.

Detection of myocardial ischemia by automated, motion-corrected, color-encoded perfusion maps compared with visual analysis of adenosine stress cardiovascular magnetic resonance imaging at 3 T: a pilot study.

PubMed

Doesch, Christina; Papavassiliu, Theano; Michaely, Henrik J; Attenberger, Ulrike I; Glielmi, Christopher; Süselbeck, Tim; Fink, Christian; Borggrefe, Martin; Schoenberg, Stefan O

2013-09-01

The purpose of this study was to compare automated, motion-corrected, color-encoded (AMC) perfusion maps with qualitative visual analysis of adenosine stress cardiovascular magnetic resonance imaging for detection of flow-limiting stenoses. Myocardial perfusion measurements applying the standard adenosine stress imaging protocol and a saturation-recovery temporal generalized autocalibrating partially parallel acquisition (t-GRAPPA) turbo fast low angle shot (Turbo FLASH) magnetic resonance imaging sequence were performed in 25 patients using a 3.0-T MAGNETOM Skyra (Siemens Healthcare Sector, Erlangen, Germany). Perfusion studies were analyzed using AMC perfusion maps and qualitative visual analysis. Angiographically detected coronary artery (CA) stenoses greater than 75% or 50% or more with a myocardial perfusion reserve index less than 1.5 were considered as hemodynamically relevant. Diagnostic performance and time requirement for both methods were compared. Interobserver and intraobserver reliability were also assessed. A total of 29 CA stenoses were included in the analysis. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for detection of ischemia on a per-patient basis were comparable using the AMC perfusion maps compared to visual analysis. On a per-CA territory basis, the attribution of an ischemia to the respective vessel was facilitated using the AMC perfusion maps. Interobserver and intraobserver reliability were better for the AMC perfusion maps (concordance correlation coefficient, 0.94 and 0.93, respectively) compared to visual analysis (concordance correlation coefficient, 0.73 and 0.79, respectively). In addition, in comparison to visual analysis, the AMC perfusion maps were able to significantly reduce analysis time from 7.7 (3.1) to 3.2 (1.9) minutes (P < 0.0001). The AMC perfusion maps yielded a diagnostic performance on a per-patient and on a per-CA territory basis comparable with the visual analysis. Furthermore, this approach demonstrated higher interobserver and intraobserver reliability as well as a better time efficiency when compared to visual analysis.

Longitudinal Patent Analysis for Nanoscale Science and Engineering: Country, Institution and Technology Field

NASA Astrophysics Data System (ADS)

Huang, Zan; Chen, Hsinchun; Yip, Alan; Ng, Gavin; Guo, Fei; Chen, Zhi-Kai; Roco, Mihail C.

2003-08-01

Nanoscale science and engineering (NSE) and related areas have seen rapid growth in recent years. The speed and scope of development in the field have made it essential for researchers to be informed on the progress across different laboratories, companies, industries and countries. In this project, we experimented with several analysis and visualization techniques on NSE-related United States patent documents to support various knowledge tasks. This paper presents results on the basic analysis of nanotechnology patents between 1976 and 2002, content map analysis and citation network analysis. The data have been obtained on individual countries, institutions and technology fields. The top 10 countries with the largest number of nanotechnology patents are the United States, Japan, France, the United Kingdom, Taiwan, Korea, the Netherlands, Switzerland, Italy and Australia. The fastest growth in the last 5 years has been in chemical and pharmaceutical fields, followed by semiconductor devices. The results demonstrate potential of information-based discovery and visualization technologies to capture knowledge regarding nanotechnology performance, transfer of knowledge and trends of development through analyzing the patent documents.

Visual investigation on the heat dissipation process of a heat sink by using digital holographic interferometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Bingjing; Zhao, Jianlin, E-mail: jlzhao@nwpu.edu.cn; Wang, Jun

2013-11-21

We present a method for visually and quantitatively investigating the heat dissipation process of plate-fin heat sinks by using digital holographic interferometry. A series of phase change maps reflecting the temperature distribution and variation trend of the air field surrounding heat sink during the heat dissipation process are numerically reconstructed based on double-exposure holographic interferometry. According to the phase unwrapping algorithm and the derived relationship between temperature and phase change of the detection beam, the full-field temperature distributions are quantitatively obtained with a reasonably high measurement accuracy. And then the impact of heat sink's channel width on the heat dissipationmore » performance in the case of natural convection is analyzed. In addition, a comparison between simulation and experiment results is given to verify the reliability of this method. The experiment results certify the feasibility and validity of the presented method in full-field, dynamical, and quantitative measurement of the air field temperature distribution, which provides a basis for analyzing the heat dissipation performance of plate-fin heat sinks.« less

The visual attention saliency map for movie retrospection

NASA Astrophysics Data System (ADS)

Rogalska, Anna; Napieralski, Piotr

2018-04-01

The visual saliency map is becoming important and challenging for many scientific disciplines (robotic systems, psychophysics, cognitive neuroscience and computer science). Map created by the model indicates possible salient regions by taking into consideration face presence and motion which is essential in motion pictures. By combining we can obtain credible saliency map with a low computational cost.

SERVIR-Africa: Developing an Integrated Platform for Floods Disaster Management in Africa

NASA Technical Reports Server (NTRS)

Macharia, Daniel; Korme, Tesfaye; Policelli, Fritz; Irwin, Dan; Adler, Bob; Hong, Yang

2010-01-01

SERVIR-Africa is an ambitious regional visualization and monitoring system that integrates remotely sensed data with predictive models and field-based data to monitor ecological processes and respond to natural disasters. It aims addressing societal benefits including floods and turning data into actionable information for decision-makers. Floods are exogenous disasters that affect many parts of Africa, probably second only to drought in terms of social-economic losses. This paper looks at SERVIR-Africa's approach to floods disaster management through establishment of an integrated platform, floods prediction models, post-event flood mapping and monitoring as well as flood maps dissemination in support of flood disaster management.

Retinotopic maps and foveal suppression in the visual cortex of amblyopic adults

PubMed Central

Conner, Ian P; Odom, J Vernon; Schwartz, Terry L; Mendola, Janine D

2007-01-01

Amblyopia is a developmental visual disorder associated with loss of monocular acuity and sensitivity as well as profound alterations in binocular integration. Abnormal connections in visual cortex are known to underlie this loss, but the extent to which these abnormalities are regionally or retinotopically specific has not been fully determined. This functional magnetic resonance imaging (fMRI) study compared the retinotopic maps in visual cortex produced by each individual eye in 19 adults (7 esotropic strabismics, 6 anisometropes and 6 controls). In our standard viewing condition, the non-tested eye viewed a dichoptic homogeneous mid-level grey stimulus, thereby permitting some degree of binocular interaction. Regions-of-interest analysis was performed for extrafoveal V1, extrafoveal V2 and the foveal representation at the occipital pole. In general, the blood oxygenation level-dependent (BOLD) signal was reduced for the amblyopic eye. At the occipital pole, population receptive fields were shifted to represent more parafoveal locations for the amblyopic eye, compared with the fellow eye, in some subjects. Interestingly, occluding the fellow eye caused an expanded foveal representation for the amblyopic eye in one early–onset strabismic subject with binocular suppression, indicating real-time cortical remapping. In addition, a few subjects actually showed increased activity in parietal and temporal cortex when viewing with the amblyopic eye. We conclude that, even in a heterogeneous population, abnormal early visual experience commonly leads to regionally specific cortical adaptations. PMID:17627994

Prediction of fracture profile using digital image correlation

NASA Astrophysics Data System (ADS)

Chaitanya, G. M. S. K.; Sasi, B.; Kumar, Anish; Babu Rao, C.; Purnachandra Rao, B.; Jayakumar, T.

2015-04-01

Digital Image Correlation (DIC) based full field strain mapping methodology is used for mapping strain on an aluminum sample subjected to tensile deformation. The local strains on the surface of the specimen are calculated at different strain intervals. Early localization of strain is observed at a total strain of 0.050ɛ; itself, whereas a visually apparent localization of strain is observed at a total strain of 0.088ɛ;. Orientation of the line of fracture (12.0°) is very close to the orientation of locus of strain maxima (11.6°) computed from the strain mapping at 0.063ɛ itself. These results show the efficacy of the DIC based method to predict the location as well as the profile of the fracture, at an early stage.

The evolution of publication hotspots in the field of telemedicine from 1962 to 2015 and differences among six countries.

PubMed

Wang, Yanjun; Zhao, Ye; Zheng, Jianzhong; Zhang, Ailian; Dong, Haiyuan

2018-04-01

Introduction Telemedicine has been implemented in many countries and has captured the attention of many researchers. Herein, we aim to quantify publication hotspots in the field of telemedicine, analyse their evolution, compare them in different countries, and provide visual representations. Methods We used software tools to process PubMed entries for a 54-year period and identified publication hotspots using keyword frequency analysis. We employed a keyword co-occurrence analysis, principal component analysis, multidimensional scaling analysis, and network visualization technology. Results The number of Medical Subject Heading (MeSH) terms increased with time. The most common subcategories of telemedicine between 1962 and 2015 were Remote Consultation, Teleradiology, and Telepathology. The most popular information communication technologies in telemedicine publications were related to the Internet and cell phones. The topics of Patient Satisfaction, Treatment Outcomes, and Home Care Services associated with telemedicine were highlighted after the 1990s. Use frequency of the terms Cell Phones and Self-Care increased drastically in the past six years, and the publication focus in six countries that had the highest output was different. Knowledge network maps and perceptual maps show the relationship between high-frequency MeSH terms. Discussion The telemedicine field has experienced significant growth and expansion in knowledge and innovation in the last 54 years. Publication hotspots for telemedicine lean towards clinical treatment, home care services, and personal care, and countries emphasize publishing in areas related to their national characteristics. This study quantitatively discusses publication hotspots, provides an objective and systematic understanding of this field, and suggests directions for future telemedicine research.

Human Computation in Visualization: Using Purpose Driven Games for Robust Evaluation of Visualization Algorithms.

PubMed

Ahmed, N; Zheng, Ziyi; Mueller, K

2012-12-01

Due to the inherent characteristics of the visualization process, most of the problems in this field have strong ties with human cognition and perception. This makes the human brain and sensory system the only truly appropriate evaluation platform for evaluating and fine-tuning a new visualization method or paradigm. However, getting humans to volunteer for these purposes has always been a significant obstacle, and thus this phase of the development process has traditionally formed a bottleneck, slowing down progress in visualization research. We propose to take advantage of the newly emerging field of Human Computation (HC) to overcome these challenges. HC promotes the idea that rather than considering humans as users of the computational system, they can be made part of a hybrid computational loop consisting of traditional computation resources and the human brain and sensory system. This approach is particularly successful in cases where part of the computational problem is considered intractable using known computer algorithms but is trivial to common sense human knowledge. In this paper, we focus on HC from the perspective of solving visualization problems and also outline a framework by which humans can be easily seduced to volunteer their HC resources. We introduce a purpose-driven game titled "Disguise" which serves as a prototypical example for how the evaluation of visualization algorithms can be mapped into a fun and addicting activity, allowing this task to be accomplished in an extensive yet cost effective way. Finally, we sketch out a framework that transcends from the pure evaluation of existing visualization methods to the design of a new one.

Visualizing the semantic content of large text databases using text maps

NASA Technical Reports Server (NTRS)

Combs, Nathan

1993-01-01

A methodology for generating text map representations of the semantic content of text databases is presented. Text maps provide a graphical metaphor for conceptualizing and visualizing the contents and data interrelationships of large text databases. Described are a set of experiments conducted against the TIPSTER corpora of Wall Street Journal articles. These experiments provide an introduction to current work in the representation and visualization of documents by way of their semantic content.

Functional Equivalence of Spatial Images from Touch and Vision: Evidence from Spatial Updating in Blind and Sighted Individuals

PubMed Central

Giudice, Nicholas A.; Betty, Maryann R.; Loomis, Jack M.

2012-01-01

This research examines whether visual and haptic map learning yield functionally equivalent spatial images in working memory, as evidenced by similar encoding bias and updating performance. In three experiments, participants learned four-point routes either by seeing or feeling the maps. At test, blindfolded participants made spatial judgments about the maps from imagined perspectives that were either aligned or misaligned with the maps as represented in working memory. Results from Experiments 1 and 2 revealed a highly similar pattern of latencies and errors between visual and haptic conditions. These findings extend the well known alignment biases for visual map learning to haptic map learning, provide further evidence of haptic updating, and most importantly, show that learning from the two modalities yields very similar performance across all conditions. Experiment 3 found the same encoding biases and updating performance with blind individuals, demonstrating that functional equivalence cannot be due to visual recoding and is consistent with an amodal hypothesis of spatial images. PMID:21299331

Deep learning with convolutional neural networks for EEG decoding and visualization.

PubMed

Schirrmeister, Robin Tibor; Springenberg, Jost Tobias; Fiederer, Lukas Dominique Josef; Glasstetter, Martin; Eggensperger, Katharina; Tangermann, Michael; Hutter, Frank; Burgard, Wolfram; Ball, Tonio

2017-11-01

Deep learning with convolutional neural networks (deep ConvNets) has revolutionized computer vision through end-to-end learning, that is, learning from the raw data. There is increasing interest in using deep ConvNets for end-to-end EEG analysis, but a better understanding of how to design and train ConvNets for end-to-end EEG decoding and how to visualize the informative EEG features the ConvNets learn is still needed. Here, we studied deep ConvNets with a range of different architectures, designed for decoding imagined or executed tasks from raw EEG. Our results show that recent advances from the machine learning field, including batch normalization and exponential linear units, together with a cropped training strategy, boosted the deep ConvNets decoding performance, reaching at least as good performance as the widely used filter bank common spatial patterns (FBCSP) algorithm (mean decoding accuracies 82.1% FBCSP, 84.0% deep ConvNets). While FBCSP is designed to use spectral power modulations, the features used by ConvNets are not fixed a priori. Our novel methods for visualizing the learned features demonstrated that ConvNets indeed learned to use spectral power modulations in the alpha, beta, and high gamma frequencies, and proved useful for spatially mapping the learned features by revealing the topography of the causal contributions of features in different frequency bands to the decoding decision. Our study thus shows how to design and train ConvNets to decode task-related information from the raw EEG without handcrafted features and highlights the potential of deep ConvNets combined with advanced visualization techniques for EEG-based brain mapping. Hum Brain Mapp 38:5391-5420, 2017. © 2017 Wiley Periodicals, Inc. © 2017 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

A novel false color mapping model-based fusion method of visual and infrared images

NASA Astrophysics Data System (ADS)

Qi, Bin; Kun, Gao; Tian, Yue-xin; Zhu, Zhen-yu

2013-12-01

A fast and efficient image fusion method is presented to generate near-natural colors from panchromatic visual and thermal imaging sensors. Firstly, a set of daytime color reference images are analyzed and the false color mapping principle is proposed according to human's visual and emotional habits. That is, object colors should remain invariant after color mapping operations, differences between infrared and visual images should be enhanced and the background color should be consistent with the main scene content. Then a novel nonlinear color mapping model is given by introducing the geometric average value of the input visual and infrared image gray and the weighted average algorithm. To determine the control parameters in the mapping model, the boundary conditions are listed according to the mapping principle above. Fusion experiments show that the new fusion method can achieve the near-natural appearance of the fused image, and has the features of enhancing color contrasts and highlighting the infrared brilliant objects when comparing with the traditional TNO algorithm. Moreover, it owns the low complexity and is easy to realize real-time processing. So it is quite suitable for the nighttime imaging apparatus.

Theoretical Foundations of Study of Cartography

NASA Astrophysics Data System (ADS)

Talhofer, Václav; Hošková-Mayerová, Šárka

2018-05-01

Cartography and geoinformatics are technical-based fields which deal with modelling and visualization of landscape in the form of a map. The theoretical foundation is necessary to obtain during study of cartography and geoinformatics based mainly on mathematics. For the given subjects, mathematics is necessary for understanding of many procedures that are connected to modelling of the Earth as a celestial body, to ways of its projection into a plane, to methods and procedures of modelling of landscape and phenomena in society and visualization of these models in the form of electronic as well as classic paper maps. Not only general mathematics, but also its extension of differential geometry of curves and surfaces, ways of approximation of lines and surfaces of functional surfaces, mathematical statistics and multi-criterial analyses seem to be suitable and necessary. Underestimation of the significance of mathematical education in cartography and geoinformatics is inappropriate and lowers competence of cartographers and professionals in geographic information science and technology to solve problems.

Brain Structure Changes Visualized in Early- and Late-Onset Blind Subjects

PubMed Central

Leporé, Natasha; Voss, Patrice; Lepore, Franco; Chou, Yi-Yu; Fortin, Madeleine; Gougoux, Frédéric; Lee, Agatha D.; Brun, Caroline; Lassonde, Maryse; Madsen, Sarah K.; Toga, Arthur W.; Thompson, Paul M.

2009-01-01

We examine 3D patterns of volume differences in the brain associated with blindness, in subjects grouped according to early and late onset. Using tensor-based morphometry, we map volume reductions and gains in 16 early-onset (EB) and 16 late-onset (LB) blind adults (onset <5 and >14 years old, respectively) relative to 16 matched sighted controls. Each subject’s structural MRI was fluidly registered to a common template. Anatomical differences between groups were mapped based on statistical analysis of the resulting deformation fields revealing profound deficits in primary and secondary visual cortices for both blind groups. Regions outside the occipital lobe showed significant hypertrophy, suggesting widespread compensatory adaptations. EBs but not LBs showed deficits in the splenium and hypertrophy in the isthmus. Gains in the isthmus and non-occipital white matter were more widespread in the EBs. These differences may reflect regional alterations in late neurodevelopmental processes, such as myelination, that continue into adulthood. PMID:19643183

Taking Place and Mapping Space: How Pre-Service Art Education Students' Visual Narratives of Field Experiences in Urban/Inner-City Schools Reveal a Spatial Knowing of Place

ERIC Educational Resources Information Center

Sutters, Justin Peter

2012-01-01

This doctoral study concerns itself with how primarily White, suburban, middle-class Art Education pre-service students are prepared in academia to teach in urban/inner-city schools. As a researcher, student-teaching supervisor, Cooperating teacher, and public school Art Educator, the author examines the shifting demographics of public education…

Efficient dense blur map estimation for automatic 2D-to-3D conversion

NASA Astrophysics Data System (ADS)

Vosters, L. P. J.; de Haan, G.

2012-03-01

Focus is an important depth cue for 2D-to-3D conversion of low depth-of-field images and video. However, focus can be only reliably estimated on edges. Therefore, Bea et al. [1] first proposed an optimization based approach to propagate focus to non-edge image portions, for single image focus editing. While their approach produces accurate dense blur maps, the computational complexity and memory requirements for solving the resulting sparse linear system with standard multigrid or (multilevel) preconditioning techniques, are infeasible within the stringent requirements of the consumer electronics and broadcast industry. In this paper we propose fast, efficient, low latency, line scanning based focus propagation, which mitigates the need for complex multigrid or (multilevel) preconditioning techniques. In addition we propose facial blur compensation to compensate for false shading edges that cause incorrect blur estimates in people's faces. In general shading leads to incorrect focus estimates, which may lead to unnatural 3D and visual discomfort. Since visual attention mostly tends to faces, our solution solves the most distracting errors. A subjective assessment by paired comparison on a set of challenging low-depth-of-field images shows that the proposed approach achieves equal 3D image quality as optimization based approaches, and that facial blur compensation results in a significant improvement.

Klein bottle logophysics: a unified principle for non-linear systems, cosmology, geophysics, biology, biomechanics and perception

NASA Astrophysics Data System (ADS)

Lucio Rapoport, Diego

2013-04-01

We present a unified principle for science that surmounts dualism, in terms of torsion fields and the non-orientable surfaces, notably the Klein Bottle and its logic, the Möbius strip and the projective plane. We apply it to the complex numbers and cosmology, to non-linear systems integrating the issue of hyperbolic divergences with the change of orientability, to the biomechanics of vision and the mammal heart, to the morphogenesis of crustal shapes on Earth in connection to the wavefronts of gravitation, elasticity and electromagnetism, to pattern recognition of artificial images and visual recognition, to neurology and the topographic maps of the sensorium, to perception, in particular of music. We develop it in terms of the fundamental 2:1 resonance inherent to the Möbius strip and the Klein Bottle, the minimal surfaces representation of the wavefronts, and the non-dual Klein Bottle logic inherent to pattern recognition, to the harmonic functions and vector fields that lay at the basis of geophysics and physics at large. We discuss the relation between the topographic maps of the sensorium, and the issue of turning inside-out of the visual world as a general principle for cognition, topological chemistry, cell biology and biological morphogenesis in particular in embryology

Visual map and instruction-based bicycle navigation: a comparison of effects on behaviour.

PubMed

de Waard, Dick; Westerhuis, Frank; Joling, Danielle; Weiland, Stella; Stadtbäumer, Ronja; Kaltofen, Leonie

2017-09-01

Cycling with a classic paper map was compared with navigating with a moving map displayed on a smartphone, and with auditory, and visual turn-by-turn route guidance. Spatial skills were found to be related to navigation performance, however only when navigating from a paper or electronic map, not with turn-by-turn (instruction based) navigation. While navigating, 25% of the time cyclists fixated at the devices that present visual information. Navigating from a paper map required most mental effort and both young and older cyclists preferred electronic over paper map navigation. In particular a turn-by-turn dedicated guidance device was favoured. Visual maps are in particular useful for cyclists with higher spatial skills. Turn-by-turn information is used by all cyclists, and it is useful to make these directions available in all devices. Practitioner Summary: Electronic navigation devices are preferred over a paper map. People with lower spatial skills benefit most from turn-by-turn guidance information, presented either auditory or on a dedicated device. People with higher spatial skills perform well with all devices. It is advised to keep in mind that all users benefit from turn-by-turn information when developing a navigation device for cyclists.

Amplitude interpretation and visualization of three-dimensional reflection data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Enachescu, M.E.

1994-07-01

Digital recording and processing of modern three-dimensional surveys allow for relative good preservation and correct spatial positioning of seismic reflection amplitude. A four-dimensional seismic reflection field matrix R (x,y,t,A), which can be computer visualized (i.e., real-time interactively rendered, edited, and animated), is now available to the interpreter. The amplitude contains encoded geological information indirectly related to lithologies and reservoir properties. The magnitude of the amplitude depends not only on the acoustic impedance contrast across a boundary, but is also strongly affected by the shape of the reflective boundary. This allows the interpreter to image subtle tectonic and structural elements notmore » obvious on time-structure maps. The use of modern workstations allows for appropriate color coding of the total available amplitude range, routine on-screen time/amplitude extraction, and late display of horizon amplitude maps (horizon slices) or complex amplitude-structure spatial visualization. Stratigraphic, structural, tectonic, fluid distribution, and paleogeographic information are commonly obtained by displaying the amplitude variation A = A(x,y,t) associated with a particular reflective surface or seismic interval. As illustrated with several case histories, traditional structural and stratigraphic interpretation combined with a detailed amplitude study generally greatly enhance extraction of subsurface geological information from a reflection data volume. In the context of three-dimensional seismic surveys, the horizon amplitude map (horizon slice), amplitude attachment to structure and [open quotes]bright clouds[close quotes] displays are very powerful tools available to the interpreter.« less

Eye Choice for Acquisition of Targets in Alternating Strabismus

PubMed Central

Economides, John R.; Adams, Daniel L.

2014-01-01

In strabismus, potentially either eye can inform the brain about the location of a target so that an accurate saccade can be made. Sixteen human subjects with alternating exotropia were tested dichoptically while viewing stimuli on a tangent screen. Each trial began with a fixation cross visible to only one eye. After the subject fixated the cross, a peripheral target visible to only one eye flashed briefly. The subject's task was to look at it. As a rule, the eye to which the target was presented was the eye that acquired the target. However, when stimuli were presented in the far nasal visual field, subjects occasionally performed a “crossover” saccade by placing the other eye on the target. This strategy avoided the need to make a large adducting saccade. In such cases, information about target location was obtained by one eye and used to program a saccade for the other eye, with a corresponding latency increase. In 10/16 subjects, targets were presented on some trials to both eyes. Binocular sensory maps were also compiled to delineate the portions of the visual scene perceived with each eye. These maps were compared with subjects' pattern of eye choice for target acquisition. There was a correspondence between suppression scotoma maps and the eye used to acquire peripheral targets. In other words, targets were fixated by the eye used to perceive them. These studies reveal how patients with alternating strabismus, despite eye misalignment, manage to localize and capture visual targets in their environment. PMID:25355212

Simulation services and analysis tools at the CCMC to study multi-scale structure and dynamics of Earth's magnetopause

NASA Astrophysics Data System (ADS)

Kuznetsova, M. M.; Liu, Y. H.; Rastaetter, L.; Pembroke, A. D.; Chen, L. J.; Hesse, M.; Glocer, A.; Komar, C. M.; Dorelli, J.; Roytershteyn, V.

2016-12-01

The presentation will provide overview of new tools, services and models implemented at the Community Coordinated Modeling Center (CCMC) to facilitate MMS dayside results analysis. We will provide updates on implementation of Particle-in-Cell (PIC) simulations at the CCMC and opportunities for on-line visualization and analysis of results of PIC simulations of asymmetric magnetic reconnection for different guide fields and boundary conditions. Fields, plasma parameters, particle distribution moments as well as particle distribution functions calculated in selected regions of the vicinity of reconnection sites can be analyzed through the web-based interactive visualization system. In addition there are options to request distribution functions in user selected regions of interest and to fly through simulated magnetic reconnection configurations and a map of distributions to facilitate comparisons with observations. A broad collection of global magnetosphere models hosted at the CCMC provide opportunity to put MMS observations and local PIC simulations into global context. We recently implemented the RECON-X post processing tool (Glocer et al, 2016) which allows users to determine the location of separator surface around closed field lines and between open field lines and solar wind field lines. The tool also finds the separatrix line where the two surfaces touch and positions of magnetic nulls. The surfaces and the separatrix line can be visualized relative to satellite positions in the dayside magnetosphere using an interactive HTML-5 visualization for each time step processed. To validate global magnetosphere models' capability to simulate locations of dayside magnetosphere boundaries we will analyze the proximity of MMS to simulated separatrix locations for a set of MMS diffusion region crossing events.

Visuomotor Transformation in the Fly Gaze Stabilization System

PubMed Central

Huston, Stephen J; Krapp, Holger G

2008-01-01

For sensory signals to control an animal's behavior, they must first be transformed into a format appropriate for use by its motor systems. This fundamental problem is faced by all animals, including humans. Beyond simple reflexes, little is known about how such sensorimotor transformations take place. Here we describe how the outputs of a well-characterized population of fly visual interneurons, lobula plate tangential cells (LPTCs), are used by the animal's gaze-stabilizing neck motor system. The LPTCs respond to visual input arising from both self-rotations and translations of the fly. The neck motor system however is involved in gaze stabilization and thus mainly controls compensatory head rotations. We investigated how the neck motor system is able to selectively extract rotation information from the mixed responses of the LPTCs. We recorded extracellularly from fly neck motor neurons (NMNs) and mapped the directional preferences across their extended visual receptive fields. Our results suggest that—like the tangential cells—NMNs are tuned to panoramic retinal image shifts, or optic flow fields, which occur when the fly rotates about particular body axes. In many cases, tangential cells and motor neurons appear to be tuned to similar axes of rotation, resulting in a correlation between the coordinate systems the two neural populations employ. However, in contrast to the primarily monocular receptive fields of the tangential cells, most NMNs are sensitive to visual motion presented to either eye. This results in the NMNs being more selective for rotation than the LPTCs. Thus, the neck motor system increases its rotation selectivity by a comparatively simple mechanism: the integration of binocular visual motion information. PMID:18651791

Spatio-Temporal Story Mapping Animation Based On Structured Causal Relationships Of Historical Events

NASA Astrophysics Data System (ADS)

Inoue, Y.; Tsuruoka, K.; Arikawa, M.

2014-04-01

In this paper, we proposed a user interface that displays visual animations on geographic maps and timelines for depicting historical stories by representing causal relationships among events for time series. We have been developing an experimental software system for the spatial-temporal visualization of historical stories for tablet computers. Our proposed system makes people effectively learn historical stories using visual animations based on hierarchical structures of different scale timelines and maps.

Web-GIS-based SARS epidemic situation visualization

NASA Astrophysics Data System (ADS)

Lu, Xiaolin

2004-03-01

In order to research, perform statistical analysis and broadcast the information of SARS epidemic situation according to the relevant spatial position, this paper proposed a unified global visualization information platform for SARS epidemic situation based on Web-GIS and scientific virtualization technology. To setup the unified global visual information platform, the architecture of Web-GIS based interoperable information system is adopted to enable public report SARS virus information to health cure center visually by using the web visualization technology. A GIS java applet is used to visualize the relationship between spatial graphical data and virus distribution, and other web based graphics figures such as curves, bars, maps and multi-dimensional figures are used to visualize the relationship between SARS virus tendency with time, patient number or locations. The platform is designed to display the SARS information in real time, simulate visually for real epidemic situation and offer an analyzing tools for health department and the policy-making government department to support the decision-making for preventing against the SARS epidemic virus. It could be used to analyze the virus condition through visualized graphics interface, isolate the areas of virus source, and control the virus condition within shortest time. It could be applied to the visualization field of SARS preventing systems for SARS information broadcasting, data management, statistical analysis, and decision supporting.

Two-dimensional nanosecond electric field mapping based on cell electropermeabilization.

PubMed

Chen, Meng-Tse; Jiang, Chunqi; Vernier, P Thomas; Wu, Yu-Hsuan; Gundersen, Martin A

2009-11-11

Nanosecond, megavolt-per-meter electric pulses cause permeabilization of cells to small molecules, programmed cell death (apoptosis) in tumor cells, and are under evaluation as a treatment for skin cancer. We use nanoelectroporation and fluorescence imaging to construct two-dimensional maps of the electric field associated with delivery of 15 ns, 10 kV pulses to monolayers of the human prostate cancer cell line PC3 from three different electrode configurations: single-needle, five-needle, and flat-cut coaxial cable. Influx of the normally impermeant fluorescent dye YO-PRO-1 serves as a sensitive indicator of membrane permeabilization. The level of fluorescence emission after pulse exposure is proportional to the applied electric field strength. Spatial electric field distributions were compared in a plane normal to the center axis and 15-20 mum from the tip of the center electrode. Measurement results agree well with models for the three electrode arrangements evaluated in this study. This live-cell method for measuring a nanosecond pulsed electric field distribution provides an operationally meaningful calibration of electrode designs for biological applications and permits visualization of the relative sensitivities of different cell types to nanoelectropulse stimulation. PACS Codes: 87.85.M-

Adaptive Registration of Varying Contrast-Weighted Images for Improved Tissue Characterization (ARCTIC): Application to T1 Mapping

PubMed Central

Roujol, Sébastien; Foppa, Murilo; Weingartner, Sebastian; Manning, Warren J.; Nezafat, Reza

2014-01-01

Purpose To propose and evaluate a novel non-rigid image registration approach for improved myocardial T1 mapping. Methods Myocardial motion is estimated as global affine motion refined by a novel local non-rigid motion estimation algorithm. A variational framework is proposed, which simultaneously estimates motion field and intensity variations, and uses an additional regularization term to constrain the deformation field using automatic feature tracking. The method was evaluated in 29 patients by measuring the DICE similarity coefficient (DSC) and the myocardial boundary error (MBE) in short axis and four chamber data. Each image series was visually assessed as “no motion” or “with motion”. Overall T1 map quality and motion artifacts were assessed in the 85 T1 maps acquired in short axis view using a 4-point scale (1-non diagnostic/severe motion artifact, 4-excellent/no motion artifact). Results Increased DSC (0.78±0.14 to 0.87±0.03, p<0.001), reduced MBE (1.29±0.72mm to 0.84±0.20mm, p<0.001), improved overall T1 map quality (2.86±1.04 to 3.49±0.77, p<0.001), and reduced T1 map motion artifacts (2.51±0.84 to 3.61±0.64, p<0.001) were obtained after motion correction of “with motion” data (~56% of data). Conclusion The proposed non-rigid registration approach reduces the respiratory-induced motion that occurs during breath-hold T1 mapping, and significantly improves T1 map quality. PMID:24798588

Mapping Metals Incorporation of a Whole Single Catalyst Particle Using Element Specific X-ray Nanotomography

DOE PAGES

Meirer, Florian; Morris, Darius T.; Kalirai, Sam; ...

2015-01-02

Full-field transmission X-ray microscopy has been used to determine the 3D structure of a whole individual fluid catalytic cracking (FCC) particle at high spatial resolution and in a fast, noninvasive manner, maintaining the full integrity of the particle. Using X-ray absorption mosaic imaging to combine multiple fields of view, computed tomography was performed to visualize the macropore structure of the catalyst and its availability for mass transport. We mapped the relative spatial distributions of Ni and Fe using multiple-energy tomography at the respective X-ray absorption K-edges and correlated these distributions with porosity and permeability of an equilibrated catalyst (E-cat) particle.more » Both metals were found to accumulate in outer layers of the particle, effectively decreasing porosity by clogging of pores and eventually restricting access into the FCC particle.« less

Can responses to basic non-numerical visual features explain neural numerosity responses?

PubMed

Harvey, Ben M; Dumoulin, Serge O

2017-04-01

Humans and many animals can distinguish between stimuli that differ in numerosity, the number of objects in a set. Human and macaque parietal lobes contain neurons that respond to changes in stimulus numerosity. However, basic non-numerical visual features can affect neural responses to and perception of numerosity, and visual features often co-vary with numerosity. Therefore, it is debated whether numerosity or co-varying low-level visual features underlie neural and behavioral responses to numerosity. To test the hypothesis that non-numerical visual features underlie neural numerosity responses in a human parietal numerosity map, we analyze responses to a group of numerosity stimulus configurations that have the same numerosity progression but vary considerably in their non-numerical visual features. Using ultra-high-field (7T) fMRI, we measure responses to these stimulus configurations in an area of posterior parietal cortex whose responses are believed to reflect numerosity-selective activity. We describe an fMRI analysis method to distinguish between alternative models of neural response functions, following a population receptive field (pRF) modeling approach. For each stimulus configuration, we first quantify the relationships between numerosity and several non-numerical visual features that have been proposed to underlie performance in numerosity discrimination tasks. We then determine how well responses to these non-numerical visual features predict the observed fMRI responses, and compare this to the predictions of responses to numerosity. We demonstrate that a numerosity response model predicts observed responses more accurately than models of responses to simple non-numerical visual features. As such, neural responses in cognitive processing need not reflect simpler properties of early sensory inputs. Copyright © 2017 Elsevier Inc. All rights reserved.

Spontaneously emerging direction selectivity maps in visual cortex through STDP.

PubMed

Wenisch, Oliver G; Noll, Joachim; Hemmen, J Leo van

2005-10-01

It is still an open question as to whether, and how, direction-selective neuronal responses in primary visual cortex are generated by feedforward thalamocortical or recurrent intracortical connections, or a combination of both. Here we present an investigation that concentrates on and, only for the sake of simplicity, restricts itself to intracortical circuits, in particular, with respect to the developmental aspects of direction selectivity through spike-timing-dependent synaptic plasticity. We show that directional responses can emerge in a recurrent network model of visual cortex with spiking neurons that integrate inputs mainly from a particular direction, thus giving rise to an asymmetrically shaped receptive field. A moving stimulus that enters the receptive field from this (preferred) direction will activate a neuron most strongly because of the increased number and/or strength of inputs from this direction and since delayed isotropic inhibition will neither overlap with, nor cancel excitation, as would be the case for other stimulus directions. It is demonstrated how direction-selective responses result from spatial asymmetries in the distribution of synaptic contacts or weights of inputs delivered to a neuron by slowly conducting intracortical axonal delay lines. By means of spike-timing-dependent synaptic plasticity with an asymmetric learning window this kind of coupling asymmetry develops naturally in a recurrent network of stochastically spiking neurons in a scenario where the neurons are activated by unidirectionally moving bar stimuli and even when only intrinsic spontaneous activity drives the learning process. We also present simulation results to show the ability of this model to produce direction preference maps similar to experimental findings.

Nano Mapper: an Internet knowledge mapping system for nanotechnology development

NASA Astrophysics Data System (ADS)

Li, Xin; Hu, Daning; Dang, Yan; Chen, Hsinchun; Roco, Mihail C.; Larson, Catherine A.; Chan, Joyce

2009-04-01

Nanotechnology research has experienced rapid growth in recent years. Advances in information technology enable efficient investigation of publications, their contents, and relationships for large sets of nanotechnology-related documents in order to assess the status of the field. This paper presents the development of a new knowledge mapping system, called Nano Mapper (http://nanomapper.eller.arizona.edu), which integrates the analysis of nanotechnology patents and research grants into a Web-based platform. The Nano Mapper system currently contains nanotechnology-related patents for 1976-2006 from the United States Patent and Trademark Office (USPTO), European Patent Office (EPO), and Japan Patent Office (JPO), as well as grant documents from the U.S. National Science Foundation (NSF) for the same time period. The system provides complex search functionalities, and makes available a set of analysis and visualization tools (statistics, trend graphs, citation networks, and content maps) that can be applied to different levels of analytical units (countries, institutions, technical fields) and for different time intervals. The paper shows important nanotechnology patenting activities at USPTO for 2005-2006 identified through the Nano Mapper system.

Nano Mapper: an Internet knowledge mapping system for nanotechnology development

PubMed Central

Hu, Daning; Dang, Yan; Chen, Hsinchun; Roco, Mihail C.; Larson, Catherine A.; Chan, Joyce

2008-01-01

Nanotechnology research has experienced rapid growth in recent years. Advances in information technology enable efficient investigation of publications, their contents, and relationships for large sets of nanotechnology-related documents in order to assess the status of the field. This paper presents the development of a new knowledge mapping system, called Nano Mapper (http://nanomapper.eller.arizona.edu), which integrates the analysis of nanotechnology patents and research grants into a Web-based platform. The Nano Mapper system currently contains nanotechnology-related patents for 1976–2006 from the United States Patent and Trademark Office (USPTO), European Patent Office (EPO), and Japan Patent Office (JPO), as well as grant documents from the U.S. National Science Foundation (NSF) for the same time period. The system provides complex search functionalities, and makes available a set of analysis and visualization tools (statistics, trend graphs, citation networks, and content maps) that can be applied to different levels of analytical units (countries, institutions, technical fields) and for different time intervals. The paper shows important nanotechnology patenting activities at USPTO for 2005–2006 identified through the Nano Mapper system. PMID:21170121

Domain Visualization Using VxInsight[R] for Science and Technology Management.

ERIC Educational Resources Information Center

Boyack, Kevin W.; Wylie, Brian N.; Davidson, George S.

2002-01-01

Presents the application of a knowledge visualization tool, VxInsight[R], to enable domain analysis for science and technology management. Uses data mining from sources of bibliographic information to define subsets of relevant information and discusses citation mapping, text mapping, and journal mapping. (Author/LRW)

Concept Mapping: A Graphical System for Understanding the Relationship between Concepts. ERIC Digest.

ERIC Educational Resources Information Center

Plotnick, Eric

This ERIC Digest discusses concept mapping, a technique for representing the structure of information visually. Concept mapping can be used to brainstorm, design complex structures, communicate complex ideas, aid learning by explicitly integrating new and old knowledge, and assess understanding or diagnose misunderstanding. Visual representation…

3D photo mosaicing of Tagiri shallow vent field by an autonomous underwater vehicle (3rd report) - Mosaicing method based on navigation data and visual features -

NASA Astrophysics Data System (ADS)

Maki, Toshihiro; Ura, Tamaki; Singh, Hanumant; Sakamaki, Takashi

Large-area seafloor imaging will bring significant benefits to various fields such as academics, resource survey, marine development, security, and search-and-rescue. The authors have proposed a navigation method of an autonomous underwater vehicle for seafloor imaging, and verified its performance through mapping tubeworm colonies with the area of 3,000 square meters using the AUV Tri-Dog 1 at Tagiri vent field, Kagoshima bay in Japan (Maki et al., 2008, 2009). This paper proposes a post-processing method to build a natural photo mosaic from a number of pictures taken by an underwater platform. The method firstly removes lens distortion, invariances of color and lighting from each image, and then ortho-rectification is performed based on camera pose and seafloor estimated by navigation data. The image alignment is based on both navigation data and visual characteristics, implemented as an expansion of the image based method (Pizarro et al., 2003). Using the two types of information realizes an image alignment that is consistent both globally and locally, as well as making the method applicable to data sets with little visual keys. The method was evaluated using a data set obtained by the AUV Tri-Dog 1 at the vent field in Sep. 2009. A seamless, uniformly illuminated photo mosaic covering the area of around 500 square meters was created from 391 pictures, which covers unique features of the field such as bacteria mats and tubeworm colonies.

Spectral separability and mapping potential of cassava leaf damage symptoms caused by whiteflies (Bemisia tabaci).

PubMed

Sims, Neil C; De Barro, Paul; Newnham, Glenn J; Kalyebi, Andrew; Macfadyen, Sarina; Malthus, Tim J

2018-01-01

This study examines whether leaf spectra can be used to measure damage to cassava plants from whitefly (Bemisia tabaci), and the potential to translate measurements from leaf to landscape scale in eastern Africa. Symptoms of the cassava brown streak disease (CBSD) and cassava mosaic disease (CMD) viruses, and sooty mould (SM) blackening of lower leaves from whiteflies feeding on the upper leaves, were measured at the leaf scale with a high-resolution spectroradiometer and a single photon avalanche diode (SPAD) meter, which retrieves relative chlorophyll concentration. Spectral measurements were compared to the five-level visual scores used to assess the severity of each of the three damaging agents in the field, and also to leaf chemistry data. Leaves exhibiting severe CBSD and CMD were spectrally indistinguishable from leaves without any symptoms. Severe SM was spectrally distinctive but is likely to be difficult to map because of its occurrence in the lower crown. SPAD measurements were highly correlated with most foliar chemistry measurements and field scores of disease severity. Regression models between simulated Sentinel 2 bands, field scores and SPAD measurements were strongest using wavelengths with high importance weightings in random forest models. SPAD measurements are highly correlated to many foliar chemistry parameters, and should be considered for use in mapping disease severity over larger areas. Remaining challenges for mapping relate to the subtle expression of symptoms, the spatial distribution of disease severity within fields, and the small size and complex structure of the cassava fields themselves. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Spectral separability and mapping potential of cassava leaf damage symptoms caused by whiteflies (Bemisia tabaci)

PubMed Central

De Barro, Paul; Newnham, Glenn J; Kalyebi, Andrew; Macfadyen, Sarina; Malthus, Tim J

2017-01-01

Abstract BACKGROUND This study examines whether leaf spectra can be used to measure damage to cassava plants from whitefly (Bemisia tabaci), and the potential to translate measurements from leaf to landscape scale in eastern Africa. Symptoms of the cassava brown streak disease (CBSD) and cassava mosaic disease (CMD) viruses, and sooty mould (SM) blackening of lower leaves from whiteflies feeding on the upper leaves, were measured at the leaf scale with a high‐resolution spectroradiometer and a single photon avalanche diode (SPAD) meter, which retrieves relative chlorophyll concentration. Spectral measurements were compared to the five‐level visual scores used to assess the severity of each of the three damaging agents in the field, and also to leaf chemistry data. RESULTS Leaves exhibiting severe CBSD and CMD were spectrally indistinguishable from leaves without any symptoms. Severe SM was spectrally distinctive but is likely to be difficult to map because of its occurrence in the lower crown. SPAD measurements were highly correlated with most foliar chemistry measurements and field scores of disease severity. Regression models between simulated Sentinel 2 bands, field scores and SPAD measurements were strongest using wavelengths with high importance weightings in random forest models. CONCLUSION SPAD measurements are highly correlated to many foliar chemistry parameters, and should be considered for use in mapping disease severity over larger areas. Remaining challenges for mapping relate to the subtle expression of symptoms, the spatial distribution of disease severity within fields, and the small size and complex structure of the cassava fields themselves. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:28851022

Visuomotor Map Determines How Visually Guided Reaching Movements are Corrected Within and Across Trials123

PubMed Central

Hirashima, Masaya

2016-01-01

Abstract When a visually guided reaching movement is unexpectedly perturbed, it is implicitly corrected in two ways: immediately after the perturbation by feedback control (online correction) and in the next movement by adjusting feedforward motor commands (offline correction or motor adaptation). Although recent studies have revealed a close relationship between feedback and feedforward controls, the nature of this relationship is not yet fully understood. Here, we show that both implicit online and offline movement corrections utilize the same visuomotor map for feedforward movement control that transforms the spatial location of visual objects into appropriate motor commands. First, we artificially distorted the visuomotor map by applying opposite visual rotations to the cursor representing the hand position while human participants reached for two different targets. This procedure implicitly altered the visuomotor map so that changes in the movement direction to the target location were more insensitive or more sensitive. Then, we examined how such visuomotor map distortion influenced online movement correction by suddenly changing the target location. The magnitude of online movement correction was altered according to the shape of the visuomotor map. We also examined offline movement correction; the aftereffect induced by visual rotation in the previous trial was modulated according to the shape of the visuomotor map. These results highlighted the importance of the visuomotor map as a foundation for implicit motor control mechanisms and the intimate relationship between feedforward control, feedback control, and motor adaptation. PMID:27275006

Visuomotor Map Determines How Visually Guided Reaching Movements are Corrected Within and Across Trials.

PubMed

Hayashi, Takuji; Yokoi, Atsushi; Hirashima, Masaya; Nozaki, Daichi

2016-01-01

When a visually guided reaching movement is unexpectedly perturbed, it is implicitly corrected in two ways: immediately after the perturbation by feedback control (online correction) and in the next movement by adjusting feedforward motor commands (offline correction or motor adaptation). Although recent studies have revealed a close relationship between feedback and feedforward controls, the nature of this relationship is not yet fully understood. Here, we show that both implicit online and offline movement corrections utilize the same visuomotor map for feedforward movement control that transforms the spatial location of visual objects into appropriate motor commands. First, we artificially distorted the visuomotor map by applying opposite visual rotations to the cursor representing the hand position while human participants reached for two different targets. This procedure implicitly altered the visuomotor map so that changes in the movement direction to the target location were more insensitive or more sensitive. Then, we examined how such visuomotor map distortion influenced online movement correction by suddenly changing the target location. The magnitude of online movement correction was altered according to the shape of the visuomotor map. We also examined offline movement correction; the aftereffect induced by visual rotation in the previous trial was modulated according to the shape of the visuomotor map. These results highlighted the importance of the visuomotor map as a foundation for implicit motor control mechanisms and the intimate relationship between feedforward control, feedback control, and motor adaptation.

The effect of linguistic and visual salience in visual world studies.

PubMed

Cavicchio, Federica; Melcher, David; Poesio, Massimo

2014-01-01

Research using the visual world paradigm has demonstrated that visual input has a rapid effect on language interpretation tasks such as reference resolution and, conversely, that linguistic material-including verbs, prepositions and adjectives-can influence fixations to potential referents. More recent research has started to explore how this effect of linguistic input on fixations is mediated by properties of the visual stimulus, in particular by visual salience. In the present study we further explored the role of salience in the visual world paradigm manipulating language-driven salience and visual salience. Specifically, we tested how linguistic salience (i.e., the greater accessibility of linguistically introduced entities) and visual salience (bottom-up attention grabbing visual aspects) interact. We recorded participants' eye-movements during a MapTask, asking them to look from landmark to landmark displayed upon a map while hearing direction-giving instructions. The landmarks were of comparable size and color, except in the Visual Salience condition, in which one landmark had been made more visually salient. In the Linguistic Salience conditions, the instructions included references to an object not on the map. Response times and fixations were recorded. Visual Salience influenced the time course of fixations at both the beginning and the end of the trial but did not show a significant effect on response times. Linguistic Salience reduced response times and increased fixations to landmarks when they were associated to a Linguistic Salient entity not present itself on the map. When the target landmark was both visually and linguistically salient, it was fixated longer, but fixations were quicker when the target item was linguistically salient only. Our results suggest that the two types of salience work in parallel and that linguistic salience affects fixations even when the entity is not visually present.

CellMap visualizes protein-protein interactions and subcellular localization

PubMed Central

Dallago, Christian; Goldberg, Tatyana; Andrade-Navarro, Miguel Angel; Alanis-Lobato, Gregorio; Rost, Burkhard

2018-01-01

Many tools visualize protein-protein interaction (PPI) networks. The tool introduced here, CellMap, adds one crucial novelty by visualizing PPI networks in the context of subcellular localization, i.e. the location in the cell or cellular component in which a PPI happens. Users can upload images of cells and define areas of interest against which PPIs for selected proteins are displayed (by default on a cartoon of a cell). Annotations of localization are provided by the user or through our in-house database. The visualizer and server are written in JavaScript, making CellMap easy to customize and to extend by researchers and developers. PMID:29497493

ZOOM Lite: next-generation sequencing data mapping and visualization software

PubMed Central

Zhang, Zefeng; Lin, Hao; Ma, Bin

2010-01-01

High-throughput next-generation sequencing technologies pose increasing demands on the efficiency, accuracy and usability of data analysis software. In this article, we present ZOOM Lite, a software for efficient reads mapping and result visualization. With a kernel capable of mapping tens of millions of Illumina or AB SOLiD sequencing reads efficiently and accurately, and an intuitive graphical user interface, ZOOM Lite integrates reads mapping and result visualization into a easy to use pipeline on desktop PC. The software handles both single-end and paired-end reads, and can output both the unique mapping result or the top N mapping results for each read. Additionally, the software takes a variety of input file formats and outputs to several commonly used result formats. The software is freely available at http://bioinfor.com/zoom/lite/. PMID:20530531

Three-dimensional geologic map of the Hayward fault, northern California: Correlation of rock unites with variations in seismicity, creep rate, and fault dip

USGS Publications Warehouse

Graymer, R.W.; Ponce, D.A.; Jachens, R.C.; Simpson, R.W.; Phelps, G.A.; Wentworth, C.M.

2005-01-01

In order to better understand mechanisms of active faults, we studied relationships between fault behavior and rock units along the Hayward fault using a three-dimensional geologic map. The three-dimensional map-constructed from hypocenters, potential field data, and surface map data-provided a geologic map of each fault surface, showing rock units on either side of the fault truncated by the fault. The two fault-surface maps were superimposed to create a rock-rock juxtaposition map. The three maps were compared with seismicity, including aseismic patches, surface creep, and fault dip along the fault, by using visuallization software to explore three-dimensional relationships. Fault behavior appears to be correlated to the fault-surface maps, but not to the rock-rock juxtaposition map, suggesting that properties of individual wall-rock units, including rock strength, play an important role in fault behavior. Although preliminary, these results suggest that any attempt to understand the detailed distribution of earthquakes or creep along a fault should include consideration of the rock types that abut the fault surface, including the incorporation of observations of physical properties of the rock bodies that intersect the fault at depth. ?? 2005 Geological Society of America.

GeoMapApp as a platform for visualizing marine data from Polar Regions

NASA Astrophysics Data System (ADS)

Nitsche, F. O.; Ryan, W. B.; Carbotte, S. M.; Ferrini, V.; Goodwillie, A. M.; O'hara, S. H.; Weissel, R.; McLain, K.; Chinhong, C.; Arko, R. A.; Chan, S.; Morton, J. J.; Pomeroy, D.

2012-12-01

To maximize the investment in expensive fieldwork the resulting data should be re-used as much as possible. In addition, unnecessary duplication of data collection effort should be avoided. This becomes even more important if access to field areas is as difficult and expensive as it is in Polar Regions. Making existing data discoverable in an easy to use platform is key to improve re-use and avoid duplication. A common obstacle is that use of existing data is often limited to specialists who know of the data existence and also have the right tools to view and analyze these data. GeoMapApp is a free, interactive, map based tool that allows users to discover, visualize, and analyze a large number of data sets. In addition to a global view, it provides polar map projections for displaying data in Arctic and Antarctic areas. Data that have currently been added to the system include Arctic swath bathymetry data collected from the USCG icebreaker Healy. These data are collected almost continuously including from cruises where bathymetry is not the main objective and for which existence of the acquired data may not be well known. In contrast, existence of seismic data from the Antarctic continental margin is well known in the seismic community. They are archived at and can be accessed through the Antarctic Seismic Data Library System (SDLS). Incorporating these data into GeoMapApp makes an even broader community aware of these data and the custom interface, which includes capabilities to visualize and explore these data, allows users without specific software or knowledge of the underlying data format to access the data. In addition to investigating these datasets, GeoMapApp provides links to the actual data sources to allow specialists the opportunity to re-use the original data. Important identification of data sources and data references are achieved on different levels. For access to the actual Antarctic seismic data GeoMapApp links to the SDLS site, where users have to register before downloading the data and where they are informed about data owners. For the swath bathymetry data GeoMapApp links to an IEDA/MGDS web page for each cruise containing detailed information about investigators and surveys.

Innovative Visualization Techniques applied to a Flood Scenario

NASA Astrophysics Data System (ADS)

Falcão, António; Ho, Quan; Lopes, Pedro; Malamud, Bruce D.; Ribeiro, Rita; Jern, Mikael

2013-04-01

The large and ever-increasing amounts of multi-dimensional, time-varying and geospatial digital information from multiple sources represent a major challenge for today's analysts. We present a set of visualization techniques that can be used for the interactive analysis of geo-referenced and time sampled data sets, providing an integrated mechanism and that aids the user to collaboratively explore, present and communicate visually complex and dynamic data. Here we present these concepts in the context of a 4 hour flood scenario from Lisbon in 2010, with data that includes measures of water column (flood height) every 10 minutes at a 4.5 m x 4.5 m resolution, topography, building damage, building information, and online base maps. Techniques we use include web-based linked views, multiple charts, map layers and storytelling. We explain two of these in more detail that are not currently in common use for visualization of data: storytelling and web-based linked views. Visual storytelling is a method for providing a guided but interactive process of visualizing data, allowing more engaging data exploration through interactive web-enabled visualizations. Within storytelling, a snapshot mechanism helps the author of a story to highlight data views of particular interest and subsequently share or guide others within the data analysis process. This allows a particular person to select relevant attributes for a snapshot, such as highlighted regions for comparisons, time step, class values for colour legend, etc. and provide a snapshot of the current application state, which can then be provided as a hyperlink and recreated by someone else. Since data can be embedded within this snapshot, it is possible to interactively visualize and manipulate it. The second technique, web-based linked views, includes multiple windows which interactively respond to the user selections, so that when selecting an object and changing it one window, it will automatically update in all the other windows. These concepts can be part of a collaborative platform, where multiple people share and work together on the data, via online access, which also allows its remote usage from a mobile platform. Storytelling augments analysis and decision-making capabilities allowing to assimilate complex situations and reach informed decisions, in addition to helping the public visualize information. In our visualization scenario, developed in the context of the VA-4D project for the European Space Agency (see http://www.ca3-uninova.org/project_va4d), we make use of the GAV (GeoAnalytics Visualization) framework, a web-oriented visual analytics application based on multiple interactive views. The final visualization that we produce includes multiple interactive views, including a dynamic multi-layer map surrounded by other visualizations such as bar charts, time graphs and scatter plots. The map provides flood and building information, on top of a base city map (street maps and/or satellite imagery provided by online map services such as Google Maps, Bing Maps etc.). Damage over time for selected buildings, damage for all buildings at a chosen time period, correlation between damage and water depth can be analysed in the other views. This interactive web-based visualization that incorporates the ideas of storytelling, web-based linked views, and other visualization techniques, for a 4 hour flood event in Lisbon in 2010, can be found online at http://www.ncomva.se/flash/projects/esa/flooding/.

The implementation of a modernized Dynamic Digital Map on Gale Crater, Mars

NASA Astrophysics Data System (ADS)

McBeck, J.; Condit, C. D.

2012-12-01

Currently, geology instructors present information to students via PowerPoint, Word, Excel and other programs that are not designed to parse or present geologic data. More tech-savvy, and perhaps better-funded, instructors use Google Earth or ArcGIS to display geologic maps and other visual information. However, Google Earth lacks the ability to present large portions of text, and ArcGIS restricts such functionality to labels and annotations. The original Dynamic Digital Map, which we have renamed Dynamic Digital Map Classic (DDMC), allows instructors to represent both visual and large portions of textual information to students. This summer we generalized the underlying architecture of DDMC, redesigned the user interface, modernized the analytical functionality, renamed the older version and labeled this new creature Dynamic Digital Map Extended (DDME). With the new DDME instructors can showcase maps, images, articles and movies, and create digital field trips. They can set the scale, coordinate system and caption of maps and images, add symbol links to maps and images that can transport the user to any specified destination—either internally (to data contained within the DDME) or externally (to a website address). Instructors and students can also calculate non-linear distances and irregular areas of maps and images, and create digital field trips with any number of stops—complete with notes and driving directions. DDMEs are perhaps best described as a sort of computerized, self-authored, interactive textbook. To display the vast capabilities of DDME, we created a DDME of Gale Crater (DDME-GC), which is the landing site of the most sophisticated NASA Mars Rover—Curiosity. DDME-GC hosts six thematic maps: a detailed geologic map provided by Brad Thompson of the Boston University Center for Remote Sensing (Thompson, et al., 2010), and five maps maintained in ASU's JMARS system, including global mosaics from Mars Global Surveyor's Mars Orbiter Laser Altimeter (MOLA), Mars Odyssey's Thermal Emission Imaging System (THEMIS), and the Mars Digital Image Model. DDME-GC offers a diverse suite of images, with over 40 images captured in the High Resolution Imaging Science Experiment (HiRISE), as well as several global mosaics created from Viking Orbiter, Hubble Telescope, THEMIS, MOLA and HiRISE data. DDME-GC also provides more than 25 articles that span subjects from the possible origins of the mound located in Gale Crater to the goals of NASA's Mars Exploration Program. The movies hosted by DDME-GC describe the difficulties of selecting a landing site for Curiosity, landing Curiosity on Mars and several other dynamic topics. The most significant advantage of the modernized DDME is its easily augmented functionality. In the future, DDME will be able to communicate with databases, import Keyhole Markup Language (KML) files from Google Earth, and be available on iOS and Android operating system. (Imagine: a field trip without the burden of notebooks, pens or pencils, paper or clipboards, with this information maintained on a mobile device.) The most recent DDME is a mere skeleton of its full capabilities—a robust architecture upon which myriad functionality can be supplemented.

Color is processed less efficiently than orientation in change detection but more efficiently in visual search.

PubMed

Huang, Liqiang

2015-05-01

Basic visual features (e.g., color, orientation) are assumed to be processed in the same general way across different visual tasks. Here, a significant deviation from this assumption was predicted on the basis of the analysis of stimulus spatial structure, as characterized by the Boolean-map notion. If a task requires memorizing the orientations of a set of bars, then the map consisting of those bars can be readily used to hold the overall structure in memory and will thus be especially useful. If the task requires visual search for a target, then the map, which contains only an overall structure, will be of little use. Supporting these predictions, the present study demonstrated that in comparison to stimulus colors, bar orientations were processed more efficiently in change-detection tasks but less efficiently in visual search tasks (Cohen's d = 4.24). In addition to offering support for the role of the Boolean map in conscious access, the present work also throws doubts on the generality of processing visual features. © The Author(s) 2015.

MOST-visualization: software for producing automated textbook-style maps of genome-scale metabolic networks.

PubMed

Kelley, James J; Maor, Shay; Kim, Min Kyung; Lane, Anatoliy; Lun, Desmond S

2017-08-15

Visualization of metabolites, reactions and pathways in genome-scale metabolic networks (GEMs) can assist in understanding cellular metabolism. Three attributes are desirable in software used for visualizing GEMs: (i) automation, since GEMs can be quite large; (ii) production of understandable maps that provide ease in identification of pathways, reactions and metabolites; and (iii) visualization of the entire network to show how pathways are interconnected. No software currently exists for visualizing GEMs that satisfies all three characteristics, but MOST-Visualization, an extension of the software package MOST (Metabolic Optimization and Simulation Tool), satisfies (i), and by using a pre-drawn overview map of metabolism based on the Roche map satisfies (ii) and comes close to satisfying (iii). MOST is distributed for free on the GNU General Public License. The software and full documentation are available at http://most.ccib.rutgers.edu/. dslun@rutgers.edu. Supplementary data are available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

StreamMap: Smooth Dynamic Visualization of High-Density Streaming Points.

PubMed

Li, Chenhui; Baciu, George; Han, Yu

2018-03-01

Interactive visualization of streaming points for real-time scatterplots and linear blending of correlation patterns is increasingly becoming the dominant mode of visual analytics for both big data and streaming data from active sensors and broadcasting media. To better visualize and interact with inter-stream patterns, it is generally necessary to smooth out gaps or distortions in the streaming data. Previous approaches either animate the points directly or present a sampled static heat-map. We propose a new approach, called StreamMap, to smoothly blend high-density streaming points and create a visual flow that emphasizes the density pattern distributions. In essence, we present three new contributions for the visualization of high-density streaming points. The first contribution is a density-based method called super kernel density estimation that aggregates streaming points using an adaptive kernel to solve the overlapping problem. The second contribution is a robust density morphing algorithm that generates several smooth intermediate frames for a given pair of frames. The third contribution is a trend representation design that can help convey the flow directions of the streaming points. The experimental results on three datasets demonstrate the effectiveness of StreamMap when dynamic visualization and visual analysis of trend patterns on streaming points are required.

Tiled vector data model for the geographical features of symbolized maps.

PubMed

Li, Lin; Hu, Wei; Zhu, Haihong; Li, You; Zhang, Hang

2017-01-01

Electronic maps (E-maps) provide people with convenience in real-world space. Although web map services can display maps on screens, a more important function is their ability to access geographical features. An E-map that is based on raster tiles is inferior to vector tiles in terms of interactive ability because vector maps provide a convenient and effective method to access and manipulate web map features. However, the critical issue regarding rendering tiled vector maps is that geographical features that are rendered in the form of map symbols via vector tiles may cause visual discontinuities, such as graphic conflicts and losses of data around the borders of tiles, which likely represent the main obstacles to exploring vector map tiles on the web. This paper proposes a tiled vector data model for geographical features in symbolized maps that considers the relationships among geographical features, symbol representations and map renderings. This model presents a method to tailor geographical features in terms of map symbols and 'addition' (join) operations on the following two levels: geographical features and map features. Thus, these maps can resolve the visual discontinuity problem based on the proposed model without weakening the interactivity of vector maps. The proposed model is validated by two map data sets, and the results demonstrate that the rendered (symbolized) web maps present smooth visual continuity.

Genome contact map explorer: a platform for the comparison, interactive visualization and analysis of genome contact maps

PubMed Central

Kumar, Rajendra; Sobhy, Haitham

2017-01-01

Abstract Hi-C experiments generate data in form of large genome contact maps (Hi-C maps). These show that chromosomes are arranged in a hierarchy of three-dimensional compartments. But to understand how these compartments form and by how much they affect genetic processes such as gene regulation, biologists and bioinformaticians need efficient tools to visualize and analyze Hi-C data. However, this is technically challenging because these maps are big. In this paper, we remedied this problem, partly by implementing an efficient file format and developed the genome contact map explorer platform. Apart from tools to process Hi-C data, such as normalization methods and a programmable interface, we made a graphical interface that let users browse, scroll and zoom Hi-C maps to visually search for patterns in the Hi-C data. In the software, it is also possible to browse several maps simultaneously and plot related genomic data. The software is openly accessible to the scientific community. PMID:28973466

Cognitive styles and mental rotation ability in map learning.

PubMed

Pazzaglia, Francesca; Moè, Angelica

2013-11-01

In inspecting, learning and reproducing a map, a wide range of abilities is potentially involved. This study examined the role of mental rotation (MR) and verbal ability, together with that of cognitive styles in map learning. As regards cognitive styles, the traditional distinction between verbalizers and visualizers has been taken into account, together with a more recent distinction between two styles of visualization: spatial and object. One hundred and seven participants filled in two questionnaires on cognitive styles: the Verbalizer-Visualizer Questionnaire (Richardson in J Ment Imag 1:109-125, 1977) and the Object-Spatial Imagery Questionnaire (Blajenkova et al. in Appl Cogn Psych 20:239-263, 2006), performed MR and verbal tests, learned two maps, and were then tested for their recall. It was found that MR ability and cognitive styles played a role in predicting map learning, with some distinctions within cognitive styles: verbal style favoured learning of one of the two maps (the one rich in verbal labels), which in turn was disadvantaged by the adoption of spatial style. Conversely, spatial style predicted learning of the other map, rich in visual features. The discussion focuses on implications for cognitive psychology and everyday cognition.

Tracking lava flow emplacement on the east rift zone of Kilauea, Hawai'i with InSAR coherence

NASA Astrophysics Data System (ADS)

Dietterich, H. R.; Schmidt, D. A.; Poland, M. P.; Cashman, K. V.

2010-12-01

Remote sensing of lava flows from the Pu`u `O`o-Kupaianaha eruption on the east rift zone of Kilauea serves to document the ongoing eruption, while yielding insights into how lava flow fields develop. InSAR is widely used to measure deformation by detecting minute changes in ground surfaces that stay correlated during repeat observations. The eruption and emplacement of fresh lava on the surface, however, disrupts the coherence of the radar echoes, allowing the area of these flows to be mapped with InSAR coherence images. We use InSAR correlation to visualize surface flow activity from 2003-2010 in order to quantify eruption rates and explore lava flow behavior from emplacement onward. This method for mapping flows does not require daylight, cloudless skies, or access to the active flow fields that is necessary for traditional visual surveys. We produce coherence maps for hundreds of 35 to 105-day periods from twelve tracks of ENVISAT SAR data using the GAMMA software package. By combining these coherence maps we create a unique dataset with which to develop this technique and amass lava flow observations. Where correlation images overlap in time, they are summed and normalized to derive a time series of surface coherence with a spatial resolution of 20 meters and a temporal resolution of as little as a few days. We identify existing stable flows by their high radar coherence, and determine a coherence threshold that is applied to each correlation image. This threshold is calibrated so as to reduce the effects of varying baseline, time duration, and atmospheric effects between images, as well as decorrelation due to vegetation. The final images illustrate lava flow activity that corresponds well with surface flow outlines and tube locations recorded by the USGS mapping effort. The InSAR-derived results serve to enhance these traditional maps by documenting pixel-scale changes over time. When compared with forward looking infrared (FLIR) thermal imagery, pixel decorrelation can be related to specific styles of activity, including surface breakouts or deformation, where field examination is difficult. We analyze these detailed snapshots of the flows to derive estimates of flow parameters, including effusion rates, lava flow areas and volumes, and surface lava flow activity over time, which provides a means of examining controls on flow paths, advance rates, and morphologies. We find that once emplaced, flows remain decorrelated for months before becoming correlated again in a piecewise fashion, suggesting that correlation rate may be dependent on thickness and cooling rate. As the eruption continues, this ever-expanding dataset has great potential for remotely capturing quantitative data from an active flow field and improving our knowledge of lava flows and their hazards.

DC current distribution mapping system of the solar panels using a HTS-SQUID gradiometer

NASA Astrophysics Data System (ADS)

Miyazaki, Shingo; Kasuya, Syohei; Mawardi Saari, Mohd; Sakai, Kenji; Kiwa, Toshihiko; Tsukamoto, Akira; Adachi, Seiji; Tanabe, Keiichi; Tsukada, Keiji

2014-05-01

Solar panels are expected to play a major role as a source of sustainable energy. In order to evaluate solar panels, non-destructive tests, such as defect inspections and response property evaluations, are necessary. We developed a DC current distribution mapping system of the solar panels using a High Critical Temperature Superconductor Superconducting Quantum Interference Device (HTS-SQUID) gradiometer with ramp edge type Josephson junctions. Two independent components of the magnetic fields perpendicular to the panel surface (∂Bz/∂x, ∂Bz/∂y) were detected. The direct current of the solar panel is visualized by calculating the composition of the two signal components, the phase angle, and mapping the DC current vector. The developed system can evaluate the uniformity of DC current distributions precisely and may be applicable for defect detection of solar panels.

Beyond sequencing: optical mapping of DNA in the age of nanotechnology and nanoscopy.

PubMed

Levy-Sakin, Michal; Ebenstein, Yuval

2013-08-01

Next generation sequencing (NGS) is revolutionizing all fields of biological research but it fails to extract the full range of information associated with genetic material. Optical mapping of DNA grants access to genetic and epigenetic information on individual DNA molecules up to ∼1 Mbp in length. Fluorescent labeling of specific sequence motifs, epigenetic marks and other genomic information on individual DNA molecules generates a high content optical barcode along the DNA. By stretching the DNA to a linear configuration this barcode may be directly visualized by fluorescence microscopy. We discuss the advances of these methods in light of recent developments in nano-fabrication and super-resolution optical imaging (nanoscopy) and review the latest achievements of optical mapping in the context of genomic analysis. Copyright © 2013 Elsevier Ltd. All rights reserved.

Real-time Author Co-citation Mapping for Online Searching.

ERIC Educational Resources Information Center

Lin, Xia; White, Howard D.; Buzydlowski, Jan

2003-01-01

Describes the design and implementation of a prototype visualization system, AuthorLink, to enhance author searching. AuthorLink is based on author co-citation analysis and visualization mapping algorithms. AuthorLink produces interactive author maps in real time from a database of 1.26 million records supplied by the Institute for Scientific…

Short-Term Plasticity of the Visuomotor Map during Grasping Movements in Humans

ERIC Educational Resources Information Center

Safstrom, Daniel; Edin, Benoni B.

2005-01-01

During visually guided grasping movements, visual information is transformed into motor commands. This transformation is known as the "visuomotor map." To investigate limitations in the short-term plasticity of the visuomotor map in normal humans, we studied the maximum grip aperture (MGA) during the reaching phase while subjects grasped objects…

An analysis of stream channel cross section technique as a means to determine anthropogenic change in second order streams at the Tenderfoot Creek Experimental Forest, Meagher County, Montana

Treesearch

Jeff Boice

1999-01-01

Five second order tributaries to Tenderfoot Creek were investigated: Upper Tenderfoot Creek, Sun Creek, Spring Park Creek, Bubbling Creek, and Stringer Creek. Second order reaches were initially located on 7.5 minute topographic maps using techniques first applied by Strahler (1952). Reach breaks were determined in the field through visual inspection. Vegetation type (...

Creation of an Accurate Algorithm to Detect Snellen Best Documented Visual Acuity from Ophthalmology Electronic Health Record Notes.

PubMed

Mbagwu, Michael; French, Dustin D; Gill, Manjot; Mitchell, Christopher; Jackson, Kathryn; Kho, Abel; Bryar, Paul J

2016-05-04

Visual acuity is the primary measure used in ophthalmology to determine how well a patient can see. Visual acuity for a single eye may be recorded in multiple ways for a single patient visit (eg, Snellen vs. Jäger units vs. font print size), and be recorded for either distance or near vision. Capturing the best documented visual acuity (BDVA) of each eye in an individual patient visit is an important step for making electronic ophthalmology clinical notes useful in research. Currently, there is limited methodology for capturing BDVA in an efficient and accurate manner from electronic health record (EHR) notes. We developed an algorithm to detect BDVA for right and left eyes from defined fields within electronic ophthalmology clinical notes. We designed an algorithm to detect the BDVA from defined fields within 295,218 ophthalmology clinical notes with visual acuity data present. About 5668 unique responses were identified and an algorithm was developed to map all of the unique responses to a structured list of Snellen visual acuities. Visual acuity was captured from a total of 295,218 ophthalmology clinical notes during the study dates. The algorithm identified all visual acuities in the defined visual acuity section for each eye and returned a single BDVA for each eye. A clinician chart review of 100 random patient notes showed a 99% accuracy detecting BDVA from these records and 1% observed error. Our algorithm successfully captures best documented Snellen distance visual acuity from ophthalmology clinical notes and transforms a variety of inputs into a structured Snellen equivalent list. Our work, to the best of our knowledge, represents the first attempt at capturing visual acuity accurately from large numbers of electronic ophthalmology notes. Use of this algorithm can benefit research groups interested in assessing visual acuity for patient centered outcome. All codes used for this study are currently available, and will be made available online at https://phekb.org.

Creation of an Accurate Algorithm to Detect Snellen Best Documented Visual Acuity from Ophthalmology Electronic Health Record Notes

PubMed Central

French, Dustin D; Gill, Manjot; Mitchell, Christopher; Jackson, Kathryn; Kho, Abel; Bryar, Paul J

2016-01-01

Background Visual acuity is the primary measure used in ophthalmology to determine how well a patient can see. Visual acuity for a single eye may be recorded in multiple ways for a single patient visit (eg, Snellen vs. Jäger units vs. font print size), and be recorded for either distance or near vision. Capturing the best documented visual acuity (BDVA) of each eye in an individual patient visit is an important step for making electronic ophthalmology clinical notes useful in research. Objective Currently, there is limited methodology for capturing BDVA in an efficient and accurate manner from electronic health record (EHR) notes. We developed an algorithm to detect BDVA for right and left eyes from defined fields within electronic ophthalmology clinical notes. Methods We designed an algorithm to detect the BDVA from defined fields within 295,218 ophthalmology clinical notes with visual acuity data present. About 5668 unique responses were identified and an algorithm was developed to map all of the unique responses to a structured list of Snellen visual acuities. Results Visual acuity was captured from a total of 295,218 ophthalmology clinical notes during the study dates. The algorithm identified all visual acuities in the defined visual acuity section for each eye and returned a single BDVA for each eye. A clinician chart review of 100 random patient notes showed a 99% accuracy detecting BDVA from these records and 1% observed error. Conclusions Our algorithm successfully captures best documented Snellen distance visual acuity from ophthalmology clinical notes and transforms a variety of inputs into a structured Snellen equivalent list. Our work, to the best of our knowledge, represents the first attempt at capturing visual acuity accurately from large numbers of electronic ophthalmology notes. Use of this algorithm can benefit research groups interested in assessing visual acuity for patient centered outcome. All codes used for this study are currently available, and will be made available online at https://phekb.org. PMID:27146002

Topological visual mapping in robotics.

PubMed

Romero, Anna; Cazorla, Miguel

2012-08-01

A key problem in robotics is the construction of a map from its environment. This map could be used in different tasks, like localization, recognition, obstacle avoidance, etc. Besides, the simultaneous location and mapping (SLAM) problem has had a lot of interest in the robotics community. This paper presents a new method for visual mapping, using topological instead of metric information. For that purpose, we propose prior image segmentation into regions in order to group the extracted invariant features in a graph so that each graph defines a single region of the image. Although others methods have been proposed for visual SLAM, our method is complete, in the sense that it makes all the process: it presents a new method for image matching; it defines a way to build the topological map; and it also defines a matching criterion for loop-closing. The matching process will take into account visual features and their structure using the graph transformation matching (GTM) algorithm, which allows us to process the matching and to remove out the outliers. Then, using this image comparison method, we propose an algorithm for constructing topological maps. During the experimentation phase, we will test the robustness of the method and its ability constructing topological maps. We have also introduced new hysteresis behavior in order to solve some problems found building the graph.

Real-time colouring and filtering with graphics shaders

NASA Astrophysics Data System (ADS)

Vohl, D.; Fluke, C. J.; Barnes, D. G.; Hassan, A. H.

2017-11-01

Despite the popularity of the Graphics Processing Unit (GPU) for general purpose computing, one should not forget about the practicality of the GPU for fast scientific visualization. As astronomers have increasing access to three-dimensional (3D) data from instruments and facilities like integral field units and radio interferometers, visualization techniques such as volume rendering offer means to quickly explore spectral cubes as a whole. As most 3D visualization techniques have been developed in fields of research like medical imaging and fluid dynamics, many transfer functions are not optimal for astronomical data. We demonstrate how transfer functions and graphics shaders can be exploited to provide new astronomy-specific explorative colouring methods. We present 12 shaders, including four novel transfer functions specifically designed to produce intuitive and informative 3D visualizations of spectral cube data. We compare their utility to classic colour mapping. The remaining shaders highlight how common computation like filtering, smoothing and line ratio algorithms can be integrated as part of the graphics pipeline. We discuss how this can be achieved by utilizing the parallelism of modern GPUs along with a shading language, letting astronomers apply these new techniques at interactive frame rates. All shaders investigated in this work are included in the open source software shwirl (Vohl 2017).

GeoPad and GeoPocket: Information Technology for Field Science Education

NASA Astrophysics Data System (ADS)

Knoop, P. A.; van der Pluijm, B.

2006-12-01

Over the past four years we have successfully incorporated and evaluated the use of field-based Information Technology (IT) in introductory through senior-level field courses offered at the University of Michigan's Camp Davis Geology Field Station, near Jackson, WY. The use of GeoPads (field-durable Tablet PCs) and GeoPockets (field-durable Pocket PCs) -- both equipped with GIS, GPS, wireless networking, electronic notebook and other pertinent software -- have significantly enhanced our field exercises and excursions, for both students and instructors. We have focused on three main applications: (1) Mapping facilitating the development of spatial reasoning skills via powerful, intuitive capabilities for in-the-field data entry, visualization, analysis, and interpretation in both 2-D and 3-D representations; (2) Field-Trips enriching the overall experience by providing in-the-field access to a broad, relevant collection of supplemental materials, such as papers, figures, maps, photos, thin section images, etc.; and, (3) Field-Based Exercises enhancing the learning opportunities afforded by field-based exercises by supporting data analysis and interpretation, while still in the context in which the data was gathered. This IT-based approach to field education utilizes standard, off-the-shelf hardware and software, and provides students with experience using tools that are increasingly relevant to their future academic or professional careers. Furthermore, this approach is generally applicable to education and research in many traditionally non-IT-savvy science domains, in addition to geology, such as archeology, biology, sociology, and natural resources.

Examples of Information Technology in Field-based Educational Settings

NASA Astrophysics Data System (ADS)

Knoop, P.; van der Pluijm, B.; Dey, E.; Burn, H.

2007-12-01

Over the last five years we have utilized ruggedized Tablet PCs and Pocket PCs in a variety of summer field courses at our Camp Davis Rocky Mountain Field Station, near Jackson, WY, as well as during departmental field trips. The courses involved range from upper-level field geology to lower-level introductory geology, as well as a mid-level environmental science course. During this period we gained a lot of experience with how to integrate information technology in field courses and field trips, as we experimented with a range of hardware and software combinations as well as different teaching approaches, some more successful than others. During much of this time we have also collaborated with external educational researchers to help us assess and understand the impact of this evolving approach to field-based instruction. Presented here are some example cases of how information technology can be used in the field for educational purposes, such as mapping projects in field courses, as a digital field notebook and reference library on field trips, and to support a mobile classroom while students are dispersed among vehicles or across a field area. We also present results from the educational evaluation of this work, which indicate that students see information technology as an important tool for their work, rather than as a novelty, and that it provides them with important visualization capabilities to enhance their understand that are not available with traditional paper mapping techniques.

Visualizing Mobility of Public Transportation System.

PubMed

Zeng, Wei; Fu, Chi-Wing; Arisona, Stefan Müller; Erath, Alexander; Qu, Huamin

2014-12-01

Public transportation systems (PTSs) play an important role in modern cities, providing shared/massive transportation services that are essential for the general public. However, due to their increasing complexity, designing effective methods to visualize and explore PTS is highly challenging. Most existing techniques employ network visualization methods and focus on showing the network topology across stops while ignoring various mobility-related factors such as riding time, transfer time, waiting time, and round-the-clock patterns. This work aims to visualize and explore passenger mobility in a PTS with a family of analytical tasks based on inputs from transportation researchers. After exploring different design alternatives, we come up with an integrated solution with three visualization modules: isochrone map view for geographical information, isotime flow map view for effective temporal information comparison and manipulation, and OD-pair journey view for detailed visual analysis of mobility factors along routes between specific origin-destination pairs. The isotime flow map linearizes a flow map into a parallel isoline representation, maximizing the visualization of mobility information along the horizontal time axis while presenting clear and smooth pathways from origin to destinations. Moreover, we devise several interactive visual query methods for users to easily explore the dynamics of PTS mobility over space and time. Lastly, we also construct a PTS mobility model from millions of real passenger trajectories, and evaluate our visualization techniques with assorted case studies with the transportation researchers.

Applying the metro map to software development management

NASA Astrophysics Data System (ADS)

Aguirregoitia, Amaia; Dolado, J. Javier; Presedo, Concepción

2010-01-01

This paper presents MetroMap, a new graphical representation model for controlling and managing the software development process. Metromap uses metaphors and visual representation techniques to explore several key indicators in order to support problem detection and resolution. The resulting visualization addresses diverse management tasks, such as tracking of deviations from the plan, analysis of patterns of failure detection and correction, overall assessment of change management policies, and estimation of product quality. The proposed visualization uses a metaphor with a metro map along with various interactive techniques to represent information concerning the software development process and to deal efficiently with multivariate visual queries. Finally, the paper shows the implementation of the tool in JavaFX with data of a real project and the results of testing the tool with the aforementioned data and users attempting several information retrieval tasks. The conclusion shows the results of analyzing user response time and efficiency using the MetroMap visualization system. The utility of the tool was positively evaluated.

Pycortex: an interactive surface visualizer for fMRI

PubMed Central

Gao, James S.; Huth, Alexander G.; Lescroart, Mark D.; Gallant, Jack L.

2015-01-01

Surface visualizations of fMRI provide a comprehensive view of cortical activity. However, surface visualizations are difficult to generate and most common visualization techniques rely on unnecessary interpolation which limits the fidelity of the resulting maps. Furthermore, it is difficult to understand the relationship between flattened cortical surfaces and the underlying 3D anatomy using tools available currently. To address these problems we have developed pycortex, a Python toolbox for interactive surface mapping and visualization. Pycortex exploits the power of modern graphics cards to sample volumetric data on a per-pixel basis, allowing dense and accurate mapping of the voxel grid across the surface. Anatomical and functional information can be projected onto the cortical surface. The surface can be inflated and flattened interactively, aiding interpretation of the correspondence between the anatomical surface and the flattened cortical sheet. The output of pycortex can be viewed using WebGL, a technology compatible with modern web browsers. This allows complex fMRI surface maps to be distributed broadly online without requiring installation of complex software. PMID:26483666

A Simple Field Guides to Identify Fire Effects on Soils

NASA Astrophysics Data System (ADS)

Robichaud, Peter

2016-04-01

Following wildfires post fire assessment personnel or teams assess immediate post-fire watershed conditions. These assessment teams must determine threats from flooding, soil erosion, and instability in a relatively short time period. Various tools and guides have been developed to assist in that process. A soil burn severity map is often the first step in the rapid assessment process. It enables BAER teams to prioritize field reviews and locate burned areas that may pose a risk to critical values within or downstream of the burned area. Five field parameters are easily determined in the field 1) remaining ground cover and characteristic, 2) ash color and depth, 3) soil structure, 4) fine roots, and 5) soil water repellency. All parameters are visual identified except water repellency which can be determined by the Water Drop Penetration Time (WDPT) test or Mini-Disk Infiltrometer (MDI). Often times the MDI test takes less time, is less subjective, and provides a relative infiltration rate which the WDPT test does not. The MDI test results are often put into "degree of soil water repellency" categories (strong, weak, and none). These field procedures that indicate the fire effects on the soil conditions help assessment teams consistently interpret, field validate and map soil burn severity.

The background is remapped across saccades.

PubMed

Cha, Oakyoon; Chong, Sang Chul

2014-02-01

Physiological studies have found that neurons prepare for impending eye movements, showing anticipatory responses to stimuli presented at the location of the post-saccadic receptive fields (RFs) (Wurtz in Vis Res 48:2070-2089, 2008). These studies proposed that visual neurons with shifting RFs prepared for the stimuli they would process after an impending saccade. Additionally, psychophysical studies have shown behavioral consequences of those anticipatory responses, including the transfer of aftereffects (Melcher in Nat Neurosci 10:903-907, 2007) and the remapping of attention (Rolfs et al. in Nat Neurosci 14:252-258, 2011). As the physiological studies proposed, the shifting RF mechanism explains the transfer of aftereffects. Recently, a new mechanism based on activation transfer via a saliency map was proposed, which accounted for the remapping of attention (Cavanagh et al. in Trends Cogn Sci 14:147-153, 2010). We hypothesized that there would be different aspects of the remapping corresponding to these different neural mechanisms. This study found that the information in the background was remapped to a similar extent as the figure, provided that the visual context remained stable. We manipulated the status of the figure and the ground in the saliency map and showed that the manipulation modulated the remapping of the figure and the ground in different ways. These results suggest that the visual system has an ability to remap the background as well as the figure, but lacks the ability to modulate the remapping of the background based on the visual context, and that different neural mechanisms might work together to maintain visual stability across saccades.

Magneto-optical visualization of three spatial components of inhomogeneous stray fields

NASA Astrophysics Data System (ADS)

Ivanov, V. E.

2012-08-01

The article deals with the physical principles of magneto-optical visualization (MO) of three spatial components of inhomogeneous stray fields with the help of FeCo metal indicator films in the longitudinal Kerr effect geometry. The inhomogeneous field is created by permanent magnets. Both p- and s-polarization light is used for obtaining MO images with their subsequent summing, subtracting and digitizing. As a result, the MO images and corresponding intensity coordinate dependences reflecting the distributions of the horizontal and vertical magnetization components in pure form have been obtained. Modeling of both the magnetization distribution in the indicator film and the corresponding MO images shows that corresponding to polar sensitivity the intensity is proportional to the normal field component, which permits normal field component mapping. Corresponding to longitudinal sensitivity, the intensity of the MO images reflects the angular distribution of the planar field component. MO images have singular points in which the planar component is zero and their movement under an externally homogeneous planar field permits obtaining of additional information on the two planar components of the field under study. The intensity distribution character in the vicinity of sources and sinks (singular points) remains the same under different orientations of the light incidence plane. The change of incident plane orientation by π/2 alters the distribution pattern in the vicinity of the saddle points.

Data Visualization Saliency Model: A Tool for Evaluating Abstract Data Visualizations

DOE PAGES

Matzen, Laura E.; Haass, Michael J.; Divis, Kristin M.; ...

2017-08-29

Evaluating the effectiveness of data visualizations is a challenging undertaking and often relies on one-off studies that test a visualization in the context of one specific task. Researchers across the fields of data science, visualization, and human-computer interaction are calling for foundational tools and principles that could be applied to assessing the effectiveness of data visualizations in a more rapid and generalizable manner. One possibility for such a tool is a model of visual saliency for data visualizations. Visual saliency models are typically based on the properties of the human visual cortex and predict which areas of a scene havemore » visual features (e.g. color, luminance, edges) that are likely to draw a viewer's attention. While these models can accurately predict where viewers will look in a natural scene, they typically do not perform well for abstract data visualizations. In this paper, we discuss the reasons for the poor performance of existing saliency models when applied to data visualizations. We introduce the Data Visualization Saliency (DVS) model, a saliency model tailored to address some of these weaknesses, and we test the performance of the DVS model and existing saliency models by comparing the saliency maps produced by the models to eye tracking data obtained from human viewers. In conclusion, we describe how modified saliency models could be used as general tools for assessing the effectiveness of visualizations, including the strengths and weaknesses of this approach.« less

Data Visualization Saliency Model: A Tool for Evaluating Abstract Data Visualizations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matzen, Laura E.; Haass, Michael J.; Divis, Kristin M.

Evaluating the effectiveness of data visualizations is a challenging undertaking and often relies on one-off studies that test a visualization in the context of one specific task. Researchers across the fields of data science, visualization, and human-computer interaction are calling for foundational tools and principles that could be applied to assessing the effectiveness of data visualizations in a more rapid and generalizable manner. One possibility for such a tool is a model of visual saliency for data visualizations. Visual saliency models are typically based on the properties of the human visual cortex and predict which areas of a scene havemore » visual features (e.g. color, luminance, edges) that are likely to draw a viewer's attention. While these models can accurately predict where viewers will look in a natural scene, they typically do not perform well for abstract data visualizations. In this paper, we discuss the reasons for the poor performance of existing saliency models when applied to data visualizations. We introduce the Data Visualization Saliency (DVS) model, a saliency model tailored to address some of these weaknesses, and we test the performance of the DVS model and existing saliency models by comparing the saliency maps produced by the models to eye tracking data obtained from human viewers. In conclusion, we describe how modified saliency models could be used as general tools for assessing the effectiveness of visualizations, including the strengths and weaknesses of this approach.« less

Field-aligned particle currents near an auroral arc.

NASA Technical Reports Server (NTRS)

Choy, L. W.; Arnoldy, R. L.; Potter, W.; Kintner, P.; Cahill, L. J., Jr.

1971-01-01

A Nike-Tomahawk rocket equipped to measure electric and magnetic fields and charged particles from a few eV to several hundred keV energy was flown into an auroral band on April 11, 1970. The purpose of this flight was to obtain evidence of the low-energy electrons and protons that constitute a field-aligned sheet current, and also to obtain the magnetic signature of such a current and the electric field in and near the auroral-arc electric current system. Particular attention was given to a sudden increase in the field-aligned current associated with a prior sudden increase in the electric field and a sudden change in the magnetic field, all occurring near the edge of a visual auroral arc. Data obtained are discussed and analyzed; they present an important contribution to the problem of mapping of atmospheric auroral phenomena to the magnetospheric equatorial plane.

StructMap: Elastic Distance Analysis of Electron Microscopy Maps for Studying Conformational Changes.

PubMed

Sanchez Sorzano, Carlos Oscar; Alvarez-Cabrera, Ana Lucia; Kazemi, Mohsen; Carazo, Jose María; Jonić, Slavica

2016-04-26

Single-particle electron microscopy (EM) has been shown to be very powerful for studying structures and associated conformational changes of macromolecular complexes. In the context of analyzing conformational changes of complexes, distinct EM density maps obtained by image analysis and three-dimensional (3D) reconstruction are usually analyzed in 3D for interpretation of structural differences. However, graphic visualization of these differences based on a quantitative analysis of elastic transformations (deformations) among density maps has not been done yet due to a lack of appropriate methods. Here, we present an approach that allows such visualization. This approach is based on statistical analysis of distances among elastically aligned pairs of EM maps (one map is deformed to fit the other map), and results in visualizing EM maps as points in a lower-dimensional distance space. The distances among points in the new space can be analyzed in terms of clusters or trajectories of points related to potential conformational changes. The results of the method are shown with synthetic and experimental EM maps at different resolutions. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

A High-Speed, Real-Time Visualization and State Estimation Platform for Monitoring and Control of Electric Distribution Systems: Implementation and Field Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lundstrom, Blake; Gotseff, Peter; Giraldez, Julieta

Continued deployment of renewable and distributed energy resources is fundamentally changing the way that electric distribution systems are controlled and operated; more sophisticated active system control and greater situational awareness are needed. Real-time measurements and distribution system state estimation (DSSE) techniques enable more sophisticated system control and, when combined with visualization applications, greater situational awareness. This paper presents a novel demonstration of a high-speed, real-time DSSE platform and related control and visualization functionalities, implemented using existing open-source software and distribution system monitoring hardware. Live scrolling strip charts of meter data and intuitive annotated map visualizations of the entire state (obtainedmore » via DSSE) of a real-world distribution circuit are shown. The DSSE implementation is validated to demonstrate provision of accurate voltage data. This platform allows for enhanced control and situational awareness using only a minimum quantity of distribution system measurement units and modest data and software infrastructure.« less

Using patient data similarities to predict radiation pneumonitis via a self-organizing map

NASA Astrophysics Data System (ADS)

Chen, Shifeng; Zhou, Sumin; Yin, Fang-Fang; Marks, Lawrence B.; Das, Shiva K.

2008-01-01

This work investigates the use of the self-organizing map (SOM) technique for predicting lung radiation pneumonitis (RP) risk. SOM is an effective method for projecting and visualizing high-dimensional data in a low-dimensional space (map). By projecting patients with similar data (dose and non-dose factors) onto the same region of the map, commonalities in their outcomes can be visualized and categorized. Once built, the SOM may be used to predict pneumonitis risk by identifying the region of the map that is most similar to a patient's characteristics. Two SOM models were developed from a database of 219 lung cancer patients treated with radiation therapy (34 clinically diagnosed with Grade 2+ pneumonitis). The models were: SOMall built from all dose and non-dose factors and, for comparison, SOMdose built from dose factors alone. Both models were tested using ten-fold cross validation and Receiver Operating Characteristics (ROC) analysis. Models SOMall and SOMdose yielded ten-fold cross-validated ROC areas of 0.73 (sensitivity/specificity = 71%/68%) and 0.67 (sensitivity/specificity = 63%/66%), respectively. The significant difference between the cross-validated ROC areas of these two models (p < 0.05) implies that non-dose features add important information toward predicting RP risk. Among the input features selected by model SOMall, the two with highest impact for increasing RP risk were: (a) higher mean lung dose and (b) chemotherapy prior to radiation therapy. The SOM model developed here may not be extrapolated to treatment techniques outside that used in our database, such as several-field lung intensity modulated radiation therapy or gated radiation therapy.

Peripersonal space representation develops independently from visual experience.

PubMed

Ricciardi, Emiliano; Menicagli, Dario; Leo, Andrea; Costantini, Marcello; Pietrini, Pietro; Sinigaglia, Corrado

2017-12-15

Our daily-life actions are typically driven by vision. When acting upon an object, we need to represent its visual features (e.g. shape, orientation, etc.) and to map them into our own peripersonal space. But what happens with people who have never had any visual experience? How can they map object features into their own peripersonal space? Do they do it differently from sighted agents? To tackle these questions, we carried out a series of behavioral experiments in sighted and congenitally blind subjects. We took advantage of a spatial alignment effect paradigm, which typically refers to a decrease of reaction times when subjects perform an action (e.g., a reach-to-grasp pantomime) congruent with that afforded by a presented object. To systematically examine peripersonal space mapping, we presented visual or auditory affording objects both within and outside subjects' reach. The results showed that sighted and congenitally blind subjects did not differ in mapping objects into their own peripersonal space. Strikingly, this mapping occurred also when objects were presented outside subjects' reach, but within the peripersonal space of another agent. This suggests that (the lack of) visual experience does not significantly affect the development of both one's own and others' peripersonal space representation.

Impact of spatial plan on the conversion of Subak rice fields and food security, in Badung and Gianyar Regencies, Bali Province

NASA Astrophysics Data System (ADS)

Lanya, Indayati; Netera Subadiyasa, N.; Ratna Adi, Gst. P.

2018-05-01

Regional Spatial Plan of Bali Province 2009-2029, allocating rice fields can be converted 10% (± 10.800 ha). Over the next 20 years, the conversion of rice field is permitted 540 ha year-1, the real condition in Bali is 800 ha year-1.Research location in Badung and Gianyar Regencies. Visual satellite image interpretation methods, digitization of on-screen, delineation of subak rice field, field survey, superimpose analysis of Spatial Plan (SP) map with rice field map, trough toolbox-analysis tools–overlay-intersect using QGIS, Harvest Index (HI) of cropping pattern in one year. SP has a negative impact on agricultural land resources and food security. Local Regulation (SP), subak rice fields outside the agricultural area licensed to be converted, and food deficits. Regency of Badung, potential land conversion of 3,324.97 ha (34.44%) from 119 subak with paddy field area of 24,184.85 ha. There are 10 subak 100% and 8 subak > 95% can be converted; projected food deficit -115.343 tons of rice by 2020 for HI 2. In Gianyar Regency, potential land conversion 13,021.41 ha (53.51%) of 66 subak with an area of 24184.85 ha; 8 subak 100% and 8 subak with area < 5 ha can be converted; projected food deficit is about -194438 tons of rice in 2040 for HI 2.

Field Ground Truthing Data Collector - a Mobile Toolkit for Image Analysis and Processing

NASA Astrophysics Data System (ADS)

Meng, X.

2012-07-01

Field Ground Truthing Data Collector is one of the four key components of the NASA funded ICCaRS project, being developed in Southeast Michigan. The ICCaRS ground truthing toolkit entertains comprehensive functions: 1) Field functions, including determining locations through GPS, gathering and geo-referencing visual data, laying out ground control points for AEROKAT flights, measuring the flight distance and height, and entering observations of land cover (and use) and health conditions of ecosystems and environments in the vicinity of the flight field; 2) Server synchronization functions, such as, downloading study-area maps, aerial photos and satellite images, uploading and synchronizing field-collected data with the distributed databases, calling the geospatial web services on the server side to conduct spatial querying, image analysis and processing, and receiving the processed results in field for near-real-time validation; and 3) Social network communication functions for direct technical assistance and pedagogical support, e.g., having video-conference calls in field with the supporting educators, scientists, and technologists, participating in Webinars, or engaging discussions with other-learning portals. This customized software package is being built on Apple iPhone/iPad and Google Maps/Earth. The technical infrastructures, data models, coupling methods between distributed geospatial data processing and field data collector tools, remote communication interfaces, coding schema, and functional flow charts will be illustrated and explained at the presentation. A pilot case study will be also demonstrated.

Climate Data Service in the FP7 EarthServer Project

NASA Astrophysics Data System (ADS)

Mantovani, Simone; Natali, Stefano; Barboni, Damiano; Grazia Veratelli, Maria

2013-04-01

EarthServer is a European Framework Program project that aims at developing and demonstrating the usability of open standards (OGC and W3C) in the management of multi-source, any-size, multi-dimensional spatio-temporal data - in short: "Big Earth Data Analytics". In order to demonstrate the feasibility of the approach, six thematic Lighthouse Applications (Cryospheric Science, Airborne Science, Atmospheric/ Climate Science, Geology, Oceanography, and Planetary Science), each with 100+ TB, are implemented. Scope of the Atmospheric/Climate lighthouse application (Climate Data Service) is to implement the system containing global to regional 2D / 3D / 4D datasets retrieved either from satellite observations, from numerical modelling and in-situ observations. Data contained in the Climate Data Service regard atmospheric profiles of temperature / humidity, aerosol content, AOT, and cloud properties provided by entities such as the European Centre for Mesoscale Weather Forecast (ECMWF), the Austrian Meteorological Service (Zentralanstalt für Meteorologie und Geodynamik - ZAMG), the Italian National Agency for new technologies, energies and sustainable development (ENEA), and the Sweden's Meteorological and Hydrological Institute (Sveriges Meteorologiska och Hydrologiska Institut -- SMHI). The system, through an easy-to-use web application permits to browse the loaded data, visualize their temporal evolution on a specific point with the creation of 2D graphs of a single field, or compare different fields on the same point (e.g. temperatures from different models and satellite observations), and visualize maps of specific fields superimposed with high resolution background maps. All data access operations and display are performed by means of OGC standard operations namely WMS, WCS and WCPS. The EarthServer project has just started its second year over a 3-years development plan: the present status the system contains subsets of the final database, with the scope of demonstrating I/O modules and visualization tools. At the end of the project all datasets will be available to the users.

Cognitive Aspects of Collaboration in 3d Virtual Environments

NASA Astrophysics Data System (ADS)

Juřík, V.; Herman, L.; Kubíček, P.; Stachoň, Z.; Šašinka, Č.

2016-06-01

Human-computer interaction has entered the 3D era. The most important models representing spatial information — maps — are transferred into 3D versions regarding the specific content to be displayed. Virtual worlds (VW) become promising area of interest because of possibility to dynamically modify content and multi-user cooperation when solving tasks regardless to physical presence. They can be used for sharing and elaborating information via virtual images or avatars. Attractiveness of VWs is emphasized also by possibility to measure operators' actions and complex strategies. Collaboration in 3D environments is the crucial issue in many areas where the visualizations are important for the group cooperation. Within the specific 3D user interface the operators' ability to manipulate the displayed content is explored regarding such phenomena as situation awareness, cognitive workload and human error. For such purpose, the VWs offer a great number of tools for measuring the operators' responses as recording virtual movement or spots of interest in the visual field. Study focuses on the methodological issues of measuring the usability of 3D VWs and comparing them with the existing principles of 2D maps. We explore operators' strategies to reach and interpret information regarding the specific type of visualization and different level of immersion.

Visualizing statistical significance of disease clusters using cartograms.

PubMed

Kronenfeld, Barry J; Wong, David W S

2017-05-15

Health officials and epidemiological researchers often use maps of disease rates to identify potential disease clusters. Because these maps exaggerate the prominence of low-density districts and hide potential clusters in urban (high-density) areas, many researchers have used density-equalizing maps (cartograms) as a basis for epidemiological mapping. However, we do not have existing guidelines for visual assessment of statistical uncertainty. To address this shortcoming, we develop techniques for visual determination of statistical significance of clusters spanning one or more districts on a cartogram. We developed the techniques within a geovisual analytics framework that does not rely on automated significance testing, and can therefore facilitate visual analysis to detect clusters that automated techniques might miss. On a cartogram of the at-risk population, the statistical significance of a disease cluster is determinate from the rate, area and shape of the cluster under standard hypothesis testing scenarios. We develop formulae to determine, for a given rate, the area required for statistical significance of a priori and a posteriori designated regions under certain test assumptions. Uniquely, our approach enables dynamic inference of aggregate regions formed by combining individual districts. The method is implemented in interactive tools that provide choropleth mapping, automated legend construction and dynamic search tools to facilitate cluster detection and assessment of the validity of tested assumptions. A case study of leukemia incidence analysis in California demonstrates the ability to visually distinguish between statistically significant and insignificant regions. The proposed geovisual analytics approach enables intuitive visual assessment of statistical significance of arbitrarily defined regions on a cartogram. Our research prompts a broader discussion of the role of geovisual exploratory analyses in disease mapping and the appropriate framework for visually assessing the statistical significance of spatial clusters.

A Visual Analytics Approach for Station-Based Air Quality Data

PubMed Central

Du, Yi; Ma, Cuixia; Wu, Chao; Xu, Xiaowei; Guo, Yike; Zhou, Yuanchun; Li, Jianhui

2016-01-01

With the deployment of multi-modality and large-scale sensor networks for monitoring air quality, we are now able to collect large and multi-dimensional spatio-temporal datasets. For these sensed data, we present a comprehensive visual analysis approach for air quality analysis. This approach integrates several visual methods, such as map-based views, calendar views, and trends views, to assist the analysis. Among those visual methods, map-based visual methods are used to display the locations of interest, and the calendar and the trends views are used to discover the linear and periodical patterns. The system also provides various interaction tools to combine the map-based visualization, trends view, calendar view and multi-dimensional view. In addition, we propose a self-adaptive calendar-based controller that can flexibly adapt the changes of data size and granularity in trends view. Such a visual analytics system would facilitate big-data analysis in real applications, especially for decision making support. PMID:28029117

A Visual Analytics Approach for Station-Based Air Quality Data.

PubMed

Du, Yi; Ma, Cuixia; Wu, Chao; Xu, Xiaowei; Guo, Yike; Zhou, Yuanchun; Li, Jianhui

2016-12-24

With the deployment of multi-modality and large-scale sensor networks for monitoring air quality, we are now able to collect large and multi-dimensional spatio-temporal datasets. For these sensed data, we present a comprehensive visual analysis approach for air quality analysis. This approach integrates several visual methods, such as map-based views, calendar views, and trends views, to assist the analysis. Among those visual methods, map-based visual methods are used to display the locations of interest, and the calendar and the trends views are used to discover the linear and periodical patterns. The system also provides various interaction tools to combine the map-based visualization, trends view, calendar view and multi-dimensional view. In addition, we propose a self-adaptive calendar-based controller that can flexibly adapt the changes of data size and granularity in trends view. Such a visual analytics system would facilitate big-data analysis in real applications, especially for decision making support.

Separate visual representations for perception and for visually guided behavior

NASA Technical Reports Server (NTRS)

Bridgeman, Bruce

1989-01-01

Converging evidence from several sources indicates that two distinct representations of visual space mediate perception and visually guided behavior, respectively. The two maps of visual space follow different rules; spatial values in either one can be biased without affecting the other. Ordinarily the two maps give equivalent responses because both are veridically in register with the world; special techniques are required to pull them apart. One such technique is saccadic suppression: small target displacements during saccadic eye movements are not preceived, though the displacements can change eye movements or pointing to the target. A second way to separate cognitive and motor-oriented maps is with induced motion: a slowly moving frame will make a fixed target appear to drift in the opposite direction, while motor behavior toward the target is unchanged. The same result occurs with stroboscopic induced motion, where the frame jump abruptly and the target seems to jump in the opposite direction. A third method of separating cognitive and motor maps, requiring no motion of target, background or eye, is the Roelofs effect: a target surrounded by an off-center rectangular frame will appear to be off-center in the direction opposite the frame. Again the effect influences perception, but in half of the subjects it does not influence pointing to the target. This experience also reveals more characteristics of the maps and their interactions with one another, the motor map apparently has little or no memory, and must be fed from the biased cognitive map if an enforced delay occurs between stimulus presentation and motor response. In designing spatial displays, the results mean that what you see isn't necessarily what you get. Displays must be designed with either perception or visually guided behavior in mind.

Local field potentials and border ownership: A conjecture about computation in visual cortex.

PubMed

Zucker, Steven W

2012-01-01

Border ownership is an intermediate-level visual task: it must integrate (upward flowing) image information about edges with (downward flowing) shape information. This highlights the familiar local-to-global aspect of border formation (linking of edge elements to form contours) with the much less studied global-to-local aspect (which edge elements form part of the same shape). To address this task we show how to incorporate certain high-level notions of distance and geometric arrangement into a form that can influence image-based edge information. The center of the argument is a reaction-diffusion equation that reveals how (global) aspects of the distance map (that is, shape) can be "read out" locally, suggesting a solution to the border ownership problem. Since the reaction-diffusion equation defines a field, a possible information processing role for the local field potential can be defined. We argue that such fields also underlie the Gestalt notion of closure, especially when it is refined using modern experimental techniques. An important implication of this theoretical argument is that, if true, then network modeling must be extended to include the substrate surrounding spiking neurons, including glia. Copyright © 2012 Elsevier Ltd. All rights reserved.

Visual classification of medical data using MLP mapping.

PubMed

Cağatay Güler, E; Sankur, B; Kahya, Y P; Raudys, S

1998-05-01

In this work we discuss the design of a novel non-linear mapping method for visual classification based on multilayer perceptrons (MLP) and assigned class target values. In training the perceptron, one or more target output values for each class in a 2-dimensional space are used. In other words, class membership information is interpreted visually as closeness to target values in a 2D feature space. This mapping is obtained by training the multilayer perceptron (MLP) using class membership information, input data and judiciously chosen target values. Weights are estimated in such a way that each training feature of the corresponding class is forced to be mapped onto the corresponding 2-dimensional target value.

Neurofilament protein defines regional patterns of cortical organization in the macaque monkey visual system: a quantitative immunohistochemical analysis

NASA Technical Reports Server (NTRS)

Hof, P. R.; Morrison, J. H.; Bloom, F. E. (Principal Investigator)

1995-01-01

Visual function in monkeys is subserved at the cortical level by a large number of areas defined by their specific physiological properties and connectivity patterns. For most of these cortical fields, a precise index of their degree of anatomical specialization has not yet been defined, although many regional patterns have been described using Nissl or myelin stains. In the present study, an attempt has been made to elucidate the regional characteristics, and to varying degrees boundaries, of several visual cortical areas in the macaque monkey using an antibody to neurofilament protein (SMI32). This antibody labels a subset of pyramidal neurons with highly specific regional and laminar distribution patterns in the cerebral cortex. Based on the staining patterns and regional quantitative analysis, as many as 28 cortical fields were reliably identified. Each field had a homogeneous distribution of labeled neurons, except area V1, where increases in layer IVB cell and in Meynert cell counts paralleled the increase in the degree of eccentricity in the visual field representation. Within the occipitotemporal pathway, areas V3 and V4 and fields in the inferior temporal cortex were characterized by a distinct population of neurofilament-rich neurons in layers II-IIIa, whereas areas located in the parietal cortex and part of the occipitoparietal pathway had a consistent population of large labeled neurons in layer Va. The mediotemporal areas MT and MST displayed a distinct population of densely labeled neurons in layer VI. Quantitative analysis of the laminar distribution of the labeled neurons demonstrated that the visual cortical areas could be grouped in four hierarchical levels based on the ratio of neuron counts between infragranular and supragranular layers, with the first (areas V1, V2, V3, and V3A) and third (temporal and parietal regions) levels characterized by low ratios and the second (areas MT, MST, and V4) and fourth (frontal regions) levels characterized by high to very high ratios. Such density trends may correspond to differential representation of corticocortically (and corticosubcortically) projecting neurons at several functional steps in the integration of the visual stimuli. In this context, it is possible that neurofilament protein is crucial for the unique capacity of certain subsets of neurons to perform the highly precise mapping functions of the monkey visual system.

Impact of visual impairment on the lives of young adults in the Netherlands: a concept-mapping approach.

PubMed

Elsman, Ellen Bernadette Maria; van Rens, Gerardus Hermanus Maria Bartholomeus; van Nispen, Ruth Marie Antoinette

2017-12-01

While the impact of visual impairments on specific aspects of young adults' lives is well recognised, a systematic understanding of its impact on all life aspects is lacking. This study aims to provide an overview of life aspects affected by visual impairment in young adults (aged 18-25 years) using a concept-mapping approach. Visually impaired young adults (n = 22) and rehabilitation professionals (n = 16) participated in online concept-mapping workshops (brainstorm procedure), to explore how having a visual impairment influences the lives of young adults. Statements were categorised based on similarity and importance. Using multidimensional scaling, concept maps were produced and interpreted. A total of 59 and 260 statements were generated by young adults and professionals, respectively, resulting in 99 individual statements after checking and deduplication. The combined concept map revealed 11 clusters: work, study, information and regulations, social skills, living independently, computer, social relationships, sport and activities, mobility, leisure time, and hobby. The concept maps provided useful insight into activities influenced by visual impairments in young adults, which can be used by rehabilitation centres to improve their services. This might help in goal setting, rehabilitation referral and successful transition to adult life, ultimately increasing participation and quality of life. Implications for rehabilitation Having a visual impairment affects various life-aspects related to participation, including activities related to work, study, social skills and relationships, activities of daily living, leisure time and mobility. Concept-mapping helped to identify the life aspects affected by low vision, and quantify these aspects in terms of importance according to young adults and low vision rehabilitation professionals. Low vision rehabilitation centres should focus on all life aspects found in this study when identifying the needs of young adults, as this might aid goal setting and rehabilitation referral, ultimately leading to more successful transitions, better participation and quality of life.

Functional MRI Representational Similarity Analysis Reveals a Dissociation between Discriminative and Relative Location Information in the Human Visual System.

PubMed

Roth, Zvi N

2016-01-01

Neural responses in visual cortex are governed by a topographic mapping from retinal locations to cortical responses. Moreover, at the voxel population level early visual cortex (EVC) activity enables accurate decoding of stimuli locations. However, in many cases information enabling one to discriminate between locations (i.e., discriminative information) may be less relevant than information regarding the relative location of two objects (i.e., relative information). For example, when planning to grab a cup, determining whether the cup is located at the same retinal location as the hand is hardly relevant, whereas the location of the cup relative to the hand is crucial for performing the action. We have previously used multivariate pattern analysis techniques to measure discriminative location information, and found the highest levels in EVC, in line with other studies. Here we show, using representational similarity analysis, that availability of discriminative information in fMRI activation patterns does not entail availability of relative information. Specifically, we find that relative location information can be reliably extracted from activity patterns in posterior intraparietal sulcus (pIPS), but not from EVC, where we find the spatial representation to be warped. We further show that this variability in relative information levels between regions can be explained by a computational model based on an array of receptive fields. Moreover, when the model's receptive fields are extended to include inhibitory surround regions, the model can account for the spatial warping in EVC. These results demonstrate how size and shape properties of receptive fields in human visual cortex contribute to the transformation of discriminative spatial representations into relative spatial representations along the visual stream.

Functional MRI Representational Similarity Analysis Reveals a Dissociation between Discriminative and Relative Location Information in the Human Visual System

PubMed Central

Roth, Zvi N.

2016-01-01

Neural responses in visual cortex are governed by a topographic mapping from retinal locations to cortical responses. Moreover, at the voxel population level early visual cortex (EVC) activity enables accurate decoding of stimuli locations. However, in many cases information enabling one to discriminate between locations (i.e., discriminative information) may be less relevant than information regarding the relative location of two objects (i.e., relative information). For example, when planning to grab a cup, determining whether the cup is located at the same retinal location as the hand is hardly relevant, whereas the location of the cup relative to the hand is crucial for performing the action. We have previously used multivariate pattern analysis techniques to measure discriminative location information, and found the highest levels in EVC, in line with other studies. Here we show, using representational similarity analysis, that availability of discriminative information in fMRI activation patterns does not entail availability of relative information. Specifically, we find that relative location information can be reliably extracted from activity patterns in posterior intraparietal sulcus (pIPS), but not from EVC, where we find the spatial representation to be warped. We further show that this variability in relative information levels between regions can be explained by a computational model based on an array of receptive fields. Moreover, when the model's receptive fields are extended to include inhibitory surround regions, the model can account for the spatial warping in EVC. These results demonstrate how size and shape properties of receptive fields in human visual cortex contribute to the transformation of discriminative spatial representations into relative spatial representations along the visual stream. PMID:27242455

Fully Convolutional Network-Based Multifocus Image Fusion.

PubMed

Guo, Xiaopeng; Nie, Rencan; Cao, Jinde; Zhou, Dongming; Qian, Wenhua

2018-07-01

As the optical lenses for cameras always have limited depth of field, the captured images with the same scene are not all in focus. Multifocus image fusion is an efficient technology that can synthesize an all-in-focus image using several partially focused images. Previous methods have accomplished the fusion task in spatial or transform domains. However, fusion rules are always a problem in most methods. In this letter, from the aspect of focus region detection, we propose a novel multifocus image fusion method based on a fully convolutional network (FCN) learned from synthesized multifocus images. The primary novelty of this method is that the pixel-wise focus regions are detected through a learning FCN, and the entire image, not just the image patches, are exploited to train the FCN. First, we synthesize 4500 pairs of multifocus images by repeatedly using a gaussian filter for each image from PASCAL VOC 2012, to train the FCN. After that, a pair of source images is fed into the trained FCN, and two score maps indicating the focus property are generated. Next, an inversed score map is averaged with another score map to produce an aggregative score map, which take full advantage of focus probabilities in two score maps. We implement the fully connected conditional random field (CRF) on the aggregative score map to accomplish and refine a binary decision map for the fusion task. Finally, we exploit the weighted strategy based on the refined decision map to produce the fused image. To demonstrate the performance of the proposed method, we compare its fused results with several start-of-the-art methods not only on a gray data set but also on a color data set. Experimental results show that the proposed method can achieve superior fusion performance in both human visual quality and objective assessment.

Design and performance of an ultra-high vacuum scanning tunneling microscope operating at dilution refrigerator temperatures and high magnetic fields.

PubMed

Misra, S; Zhou, B B; Drozdov, I K; Seo, J; Urban, L; Gyenis, A; Kingsley, S C J; Jones, H; Yazdani, A

2013-10-01

We describe the construction and performance of a scanning tunneling microscope capable of taking maps of the tunneling density of states with sub-atomic spatial resolution at dilution refrigerator temperatures and high (14 T) magnetic fields. The fully ultra-high vacuum system features visual access to a two-sample microscope stage at the end of a bottom-loading dilution refrigerator, which facilitates the transfer of in situ prepared tips and samples. The two-sample stage enables location of the best area of the sample under study and extends the experiment lifetime. The successful thermal anchoring of the microscope, described in detail, is confirmed through a base temperature reading of 20 mK, along with a measured electron temperature of 250 mK. Atomically resolved images, along with complementary vibration measurements, are presented to confirm the effectiveness of the vibration isolation scheme in this instrument. Finally, we demonstrate that the microscope is capable of the same level of performance as typical machines with more modest refrigeration by measuring spectroscopic maps at base temperature both at zero field and in an applied magnetic field.

Positive Contrast Visualization of Nitinol Devices using Susceptibility Gradient Mapping

PubMed Central

Vonken, Evert-jan P.A.; Schär, Michael; Stuber, Matthias

2008-01-01

MRI visualization of devices is traditionally based on the signal loss due to T2* effects originating from the local susceptibility differences. To visualize nitinol devices with positive contrast a recently introduced post processing method is adapted to map the induced susceptibility gradients. This method operates on regular gradient echo MR images and maps the shift in k-space in a (small) neighborhood of every voxel by Fourier analysis followed by a center of mass calculation. The quantitative map of the local shifts generates the positive contrast image of the devices, while areas without susceptibility gradients render a background with noise only. The positive signal response of this method depends only on the choice of the voxel neighborhood size. The properties of the method are explained and the visualization of a nitinol wire and two stents are shown for illustration. PMID:18727096

Mapping lava flow textures using three-dimensional measures of surface roughness

NASA Astrophysics Data System (ADS)

Mallonee, H. C.; Kobs-Nawotniak, S. E.; McGregor, M.; Hughes, S. S.; Neish, C.; Downs, M.; Delparte, D.; Lim, D. S. S.; Heldmann, J. L.

2016-12-01

Lava flow emplacement conditions are reflected in the surface textures of a lava flow; unravelling these conditions is crucial to understanding the eruptive history and characteristics of basaltic volcanoes. Mapping lava flow textures using visual imagery alone is an inherently subjective process, as these images generally lack the resolution needed to make these determinations. Our team has begun mapping lava flow textures using visual spectrum imagery, which is an inherently subjective process involving the challenge of identifying transitional textures such as rubbly and slabby pāhoehoe, as these textures are similar in appearance and defined qualitatively. This is particularly problematic for interpreting planetary lava flow textures, where we have more limited data. We present a tool to objectively classify lava flow textures based on quantitative measures of roughness, including the 2D Hurst exponent, RMS height, and 2D:3D surface area ratio. We collected aerial images at Craters of the Moon National Monument (COTM) using Unmanned Aerial Vehicles (UAVs) in 2015 and 2016 as part of the FINESSE (Field Investigations to Enable Solar System Science and Exploration) and BASALT (Biologic Analog Science Associated with Lava Terrains) research projects. The aerial images were stitched together to create Digital Terrain Models (DTMs) with resolutions on the order of centimeters. The DTMs were evaluated by the classification tool described above, with output compared against field assessment of the texture. Further, the DTMs were downsampled and reevaluated to assess the efficacy of the classification tool at data resolutions similar to current datasets from other planetary bodies. This tool allows objective classification of lava flow texture, which enables more accurate interpretations of flow characteristics. This work also gives context for interpretations of flows with comparatively low data resolutions, such as those on the Moon and Mars. Textural maps based on quantitative measures of roughness are a valuable asset for studies of lava flows on Earth and other planetary bodies.

Adaptation, perceptual learning, and plasticity of brain functions.

PubMed

Horton, Jonathan C; Fahle, Manfred; Mulder, Theo; Trauzettel-Klosinski, Susanne

2017-03-01

The capacity for functional restitution after brain damage is quite different in the sensory and motor systems. This series of presentations highlights the potential for adaptation, plasticity, and perceptual learning from an interdisciplinary perspective. The chances for restitution in the primary visual cortex are limited. Some patterns of visual field loss and recovery after stroke are common, whereas others are impossible, which can be explained by the arrangement and plasticity of the cortical map. On the other hand, compensatory mechanisms are effective, can occur spontaneously, and can be enhanced by training. In contrast to the human visual system, the motor system is highly flexible. This is based on special relationships between perception and action and between cognition and action. In addition, the healthy adult brain can learn new functions, e.g. increasing resolution above the retinal one. The significance of these studies for rehabilitation after brain damage will be discussed.

Emotion computing using Word Mover's Distance features based on Ren_CECps.

PubMed

Ren, Fuji; Liu, Ning

2018-01-01

In this paper, we propose an emotion separated method(SeTF·IDF) to assign the emotion labels of sentences with different values, which has a better visual effect compared with the values represented by TF·IDF in the visualization of a multi-label Chinese emotional corpus Ren_CECps. Inspired by the enormous improvement of the visualization map propelled by the changed distances among the sentences, we being the first group utilizes the Word Mover's Distance(WMD) algorithm as a way of feature representation in Chinese text emotion classification. Our experiments show that both in 80% for training, 20% for testing and 50% for training, 50% for testing experiments of Ren_CECps, WMD features get the best f1 scores and have a greater increase compared with the same dimension feature vectors obtained by dimension reduction TF·IDF method. Compared experiments in English corpus also show the efficiency of WMD features in the cross-language field.

Visualization and automatic detection of defect distribution in GaN atomic structure from sampling Moiré phase.

PubMed

Wang, Qinghua; Ri, Shien; Tsuda, Hiroshi; Kodera, Masako; Suguro, Kyoichi; Miyashita, Naoto

2017-09-19

Quantitative detection of defects in atomic structures is of great significance to evaluating product quality and exploring quality improvement process. In this study, a Fourier transform filtered sampling Moire technique was proposed to visualize and detect defects in atomic arrays in a large field of view. Defect distributions, defect numbers and defect densities could be visually and quantitatively determined from a single atomic structure image at low cost. The effectiveness of the proposed technique was verified from numerical simulations. As an application, the dislocation distributions in a GaN/AlGaN atomic structure in two directions were magnified and displayed in Moire phase maps, and defect locations and densities were detected automatically. The proposed technique is able to provide valuable references to material scientists and engineers by checking the effect of various treatments for defect reduction. © 2017 IOP Publishing Ltd.

Evaluation of Mapping Methodologies at a Legacy Test Site

NASA Astrophysics Data System (ADS)

Sussman, A. J.; Schultz-Fellenz, E. S.; Roback, R. C.; Kelley, R. E.; Drellack, S.; Reed, D.; Miller, E.; Cooper, D. I.; Sandoval, M.; Wang, R.

2013-12-01

On June 12th, 1985, a nuclear test with an announced yield between 20-150kt was detonated in rhyolitic lava in a vertical emplacement borehole at a depth of 608m below the surface. This test did not collapse to the surface and form a crater, but rather resulted in a subsurface collapse with more subtle surface expressions of deformation, providing an opportunity to evaluate the site using a number of surface mapping methodologies. The site was investigated over a two-year time span by several mapping teams. In order to determine the most time efficient and accurate approach for mapping post-shot surface features at a legacy test site, a number of different techniques were employed. The site was initially divided into four quarters, with teams applying various methodologies, techniques, and instrumentations to each quarter. Early methods included transect lines and site gridding with a Brunton pocket transit, flagging tape, measuring tape, and stakes; surveying using a hand-held personal GPS to locate observed features with an accuracy of × 5-10m; and extensive photo-documentation. More recent methods have incorporated the use of near survey grade GPS devices to allow careful location and mapping of surface features. Initially, gridding was employed along with the high resolution GPS surveys, but this was found to be time consuming and of little observational value. Raw visual observation (VOB) data included GPS coordinates for artifacts or features of interest, field notes, and photographs. A categorization system was used to organize the myriad of items, in order to aid in database searches and for visual presentation of findings. The collected data set was imported into a geographic information system (GIS) as points, lines, or polygons and overlain onto a digital color orthophoto map of the test site. Once these data were mapped, spectral data were collected using a high resolution field spectrometer. In addition to geo-locating the field observations with 10cm resolution GPS, LiDAR and hyperspectral imagery were also acquired. The LiDAR and hyperspectral data are being processed and will be added to the existing geo-referenced database as separate information layers for remote sensing analysis of surface features associated with the legacy test. By consolidating the various components of a VOB data point (coordinates, photo and item description) into a standalone database, searching or querying for other components or collects such as subsurface geophysical and/or airborne imagery is made much easier. Work by Los Alamos National Laboratory was sponsored by the National Nuclear Security Administration Award No. DE-AC52-06NA25946/NST10-NCNS-PD00. Work by National Security Technologies, LLC, was performed under Contract No. DE AC52 06NA25946 with the U.S. Department of Energy.

Visualizing the Zero-Potential Line of Bipolar Electrodes with Arbitrary Geometry.

PubMed

Li, Meng; Liu, Shasha; Jiang, Yingyan; Wang, Wei

2018-06-05

In a typical bipolar electrochemistry (BPE) configuration, voltage applied between the two driving electrodes induced a potential drop through solution filled in the microchannel, resulting in an interfacial potential difference between solution and BPE varied along the BPE. In the present work, we employed a recently developed plasmonic imaging technique to map the distribution of surface potential of bipolar electrodes with various geometries including round, triangle, hexagon, star, and rhombus shapes under the nonfaradaic charging process, from which the line of zero potential (LZP) was visualized and determined. We further investigated the dependence of LZP on electrode geometry and the distribution of external electric field and explained the experimental results with a charge balance mechanism. The triangular and star-shaped BPEs show quite different LZP features from the other ones with symmetrical geometry. These experimentally obtained potential distributions are all in good agreement with electromagnetic simulations. Finally, the line of zero overpotential (LZO) of the triangular-shaped BPE under faradaic reactions were investigated. The results confirm the shift of LZO when faradaic reactions occurred at the corresponding ends of BPE. The present work demonstrates the first experimental capability to map the potential distribution of BPE with arbitrary geometry under an arbitrary driving field. It is anticipated to help the design and optimization on the geometry of electrodes and microchannels with implications for boosting their applications in chemical sensing and materials synthesis.

Fuel Cell Backup Power Geographical Visualization Map (Fact Sheet)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

2012-12-01

This NREL Hydrogen and Fuel Cell Technical Highlight describes a time-lapse geographical visualization map of early market use of fuel cells for telecommunications backup power. The map synthesizes data being analyzed by NREL's Technology Validation team for the U.S. Department of Energy (DOE) Fuel Cell Technologies Program with DOE's publicly available annual summaries of electric disturbance events.

London through Rose-Colored Graphics: Visual Rhetoric and Information Graphic Design in Charles Booth's Maps of London Poverty

ERIC Educational Resources Information Center

Kimball, Miles A.

2006-01-01

In this article, I examine a historical information graphic--Charles Booth's maps of London poverty (1889-1902)--to analyze the cultural basis of ideas of transparency and clarity in information graphics. I argue that Booth's maps derive their rhetorical power from contemporary visual culture as much as from their scientific authority. The visual…

Creating Visual Aids with Graphic Organisers on an Infinite Canvas--The Impact on the Presenter

ERIC Educational Resources Information Center

Casteleyn, Jordi; Mottart, Andre; Valcke, Martin

2015-01-01

Instead of the traditional set of slides, the visual aids of a presentation can now be graphic organisers (concept maps, knowledge maps, mind maps) on an infinite canvas. Constructing graphic organisers has a beneficial impact on learning, but this topic has not been studied in the context of giving a presentation. The present study examined this…

Analysis of recurrent patterns in toroidal magnetic fields.

PubMed

Sanderson, Allen R; Chen, Guoning; Tricoche, Xavier; Pugmire, David; Kruger, Scott; Breslau, Joshua

2010-01-01

In the development of magnetic confinement fusion which will potentially be a future source for low cost power, physicists must be able to analyze the magnetic field that confines the burning plasma. While the magnetic field can be described as a vector field, traditional techniques for analyzing the field's topology cannot be used because of its Hamiltonian nature. In this paper we describe a technique developed as a collaboration between physicists and computer scientists that determines the topology of a toroidal magnetic field using fieldlines with near minimal lengths. More specifically, we analyze the Poincaré map of the sampled fieldlines in a Poincaré section including identifying critical points and other topological features of interest to physicists. The technique has been deployed into an interactive parallel visualization tool which physicists are using to gain new insight into simulations of magnetically confined burning plasmas.

Data Visualization of Lunar Orbiter KAGUYA (SELENE) using web-based GIS

NASA Astrophysics Data System (ADS)

Okumura, H.; Sobue, S.; Yamamoto, A.; Fujita, T.

2008-12-01

The Japanese Lunar Orbiter KAGUYA (SELENE) was launched on Sep.14 2007, and started nominal observation from Dec. 21 2007. KAGUYA has 15 ongoing observation missions and is obtaining various physical quantity data of the moon such as elemental abundance, mineralogical composition, geological feature, magnetic field and gravity field. We are working on the visualization of these data and the application of them to web-based GIS. Our purpose of data visualization is the promotion of science and education and public outreach (EPO). As for scientific usage and public outreach, we already constructed KAGUYA Web Map Server (WMS) at JAXA Sagamihara Campus and began to test it among internal KAGUYA project. KAGUYA science team plans the integrated science using the data of multiple instruments with the aim of obtaining the new findings of the origin and the evolution of the moon. In the study of the integrated science, scientists have to access, compare and analyze various types of data with different resolution. Web-based GIS will allow users to map, overlay and share the data and information easily. So it will be the best way to progress such a study and we are developing the KAGUYA WMS as a platform of the KAGUYA integrated science. For the purpose of EPO, we are customizing NASA World Wind (NWW) JAVA for KAGUYA supported by NWW project. Users will be able to search and view many images and movies of KAGUYA on NWW JAVA in the easy and attractive way. In addition, we are considering applying KAGUYA images to Google Moon with KML format and adding KAGUYA movies to Google/YouTube.

How Visual Is the Visual Cortex? Comparing Connectional and Functional Fingerprints between Congenitally Blind and Sighted Individuals.

PubMed

Wang, Xiaoying; Peelen, Marius V; Han, Zaizhu; He, Chenxi; Caramazza, Alfonso; Bi, Yanchao

2015-09-09

Classical animal visual deprivation studies and human neuroimaging studies have shown that visual experience plays a critical role in shaping the functionality and connectivity of the visual cortex. Interestingly, recent studies have additionally reported circumscribed regions in the visual cortex in which functional selectivity was remarkably similar in individuals with and without visual experience. Here, by directly comparing resting-state and task-based fMRI data in congenitally blind and sighted human subjects, we obtained large-scale continuous maps of the degree to which connectional and functional "fingerprints" of ventral visual cortex depend on visual experience. We found a close agreement between connectional and functional maps, pointing to a strong interdependence of connectivity and function. Visual experience (or the absence thereof) had a pronounced effect on the resting-state connectivity and functional response profile of occipital cortex and the posterior lateral fusiform gyrus. By contrast, connectional and functional fingerprints in the anterior medial and posterior lateral parts of the ventral visual cortex were statistically indistinguishable between blind and sighted individuals. These results provide a large-scale mapping of the influence of visual experience on the development of both functional and connectivity properties of visual cortex, which serves as a basis for the formulation of new hypotheses regarding the functionality and plasticity of specific subregions. Significance statement: How is the functionality and connectivity of the visual cortex shaped by visual experience? By directly comparing resting-state and task-based fMRI data in congenitally blind and sighted subjects, we obtained large-scale continuous maps of the degree to which connectional and functional "fingerprints" of ventral visual cortex depend on visual experience. In addition to revealing regions that are strongly dependent on visual experience (early visual cortex and posterior fusiform gyrus), our results showed regions in which connectional and functional patterns are highly similar in blind and sighted individuals (anterior medial and posterior lateral ventral occipital temporal cortex). These results serve as a basis for the formulation of new hypotheses regarding the functionality and plasticity of specific subregions of the visual cortex. Copyright © 2015 the authors 0270-6474/15/3512545-15$15.00/0.

Automated objective characterization of visual field defects in 3D

NASA Technical Reports Server (NTRS)

Fink, Wolfgang (Inventor)

2006-01-01

A method and apparatus for electronically performing a visual field test for a patient. A visual field test pattern is displayed to the patient on an electronic display device and the patient's responses to the visual field test pattern are recorded. A visual field representation is generated from the patient's responses. The visual field representation is then used as an input into a variety of automated diagnostic processes. In one process, the visual field representation is used to generate a statistical description of the rapidity of change of a patient's visual field at the boundary of a visual field defect. In another process, the area of a visual field defect is calculated using the visual field representation. In another process, the visual field representation is used to generate a statistical description of the volume of a patient's visual field defect.

The primary visual cortex in the neural circuit for visual orienting

NASA Astrophysics Data System (ADS)

Zhaoping, Li

The primary visual cortex (V1) is traditionally viewed as remote from influencing brain's motor outputs. However, V1 provides the most abundant cortical inputs directly to the sensory layers of superior colliculus (SC), a midbrain structure to command visual orienting such as shifting gaze and turning heads. I will show physiological, anatomical, and behavioral data suggesting that V1 transforms visual input into a saliency map to guide a class of visual orienting that is reflexive or involuntary. In particular, V1 receives a retinotopic map of visual features, such as orientation, color, and motion direction of local visual inputs; local interactions between V1 neurons perform a local-to-global computation to arrive at a saliency map that highlights conspicuous visual locations by higher V1 responses. The conspicuous location are usually, but not always, where visual input statistics changes. The population V1 outputs to SC, which is also retinotopic, enables SC to locate, by lateral inhibition between SC neurons, the most salient location as the saccadic target. Experimental tests of this hypothesis will be shown. Variations of the neural circuit for visual orienting across animal species, with more or less V1 involvement, will be discussed. Supported by the Gatsby Charitable Foundation.

Usage of Data-Encoded Web Maps with Client Side Color Rendering for Combined Data Access, Visualization and Modeling Purposes

NASA Technical Reports Server (NTRS)

Pliutau, Denis; Prasad, Narashimha S.

2013-01-01

Current approaches to satellite observation data storage and distribution implement separate visualization and data access methodologies which often leads to the need in time consuming data ordering and coding for applications requiring both visual representation as well as data handling and modeling capabilities. We describe an approach we implemented for a data-encoded web map service based on storing numerical data within server map tiles and subsequent client side data manipulation and map color rendering. The approach relies on storing data using the lossless compression Portable Network Graphics (PNG) image data format which is natively supported by web-browsers allowing on-the-fly browser rendering and modification of the map tiles. The method is easy to implement using existing software libraries and has the advantage of easy client side map color modifications, as well as spatial subsetting with physical parameter range filtering. This method is demonstrated for the ASTER-GDEM elevation model and selected MODIS data products and represents an alternative to the currently used storage and data access methods. One additional benefit includes providing multiple levels of averaging due to the need in generating map tiles at varying resolutions for various map magnification levels. We suggest that such merged data and mapping approach may be a viable alternative to existing static storage and data access methods for a wide array of combined simulation, data access and visualization purposes.

Geonucleus, the freeware application for managing geological mapping data in GIS

NASA Astrophysics Data System (ADS)

Albert, Gáspár

2016-04-01

Geological mapping is the most traditional way of collecting information from the deposits and rocks. The traditional technique of the documentation was refined by generations of geologists. These traditions were implemented into Geonucleus to create a tool for precise data-recording after fieldwork, but giving the freedom of pondering the details of the observation as well. In 2012 a general xml-based data structure was worked out for storing field observations for the Geological Institute of Hungary (Albert et al. 2012). This structure was implemented into the desktop version of Geonucleus, which creates a database of the recorded data on the client computer. The application saves the complete database in one file, which can be loaded into a GIS. The observations can be saved in simple text format as well, but primarily the kml (Keyhole Markup Languege) is supported. This way, the observations are visualized in comprehensible forms (e.g. on a 3D surface model with satellite photos in Google Earth). If the kml is directly visualized in Google Earth, an info-bubble will appear via clicking on a pinpoint. It displays all the metadata (e.g. index, coordinates, date, logger name, etc.), the descriptions and the photos of the observed site. If a more general GIS application is the aim (e.g. Global Mapper or QGIS), the file can be saved in a different format, but still in a kml-structure. The simple text format is recommended if the observations are to be imported in a user-defined relational database system (RDB). Report text-type is also available if a detailed description of one or more observed site is needed. Importing waypoint gpx-files can quicken the logging. The code was written in VisualBasic.Net. The app is freely accessible from the geonucleus.elte.hu site and it can be installed on any system, which has the .Net framework 4.0 or higher. The software is bilingual (English and Hungarian), and the app is designed for general geological mapping purposes (e.g. quick logging of field trips). The layout of the GUI has three components: 1) metadata area, 2) general description area with unlimited storing capacity, 3) switchable panels for observations, measurements, photos and notes. The latter includes panels for stratigraphy, structures, fossils, samples, photo uploads and general notes. Details like the sequence and contact type of layers, the parameters of structures and slickensides, name and condition of fossils and purpose of sampling are also available to log (but not compulsorily). It is also a tool for teaching geological mapping, since the available parameters - listed in the app - draws attention to the details, which are to be observed on the field. Reference: Albert G, Csillag G, Fodor L, Zentai L. 2012: Visualisation of Geological Observations on Web 2.0 Based Maps, in: Zentai, L. and Reyes-Nunez, J (eds.): Maps for the Future - Children, Education and Internet, Series: Lecture Notes in Geoinformation and Cartography, Tentative volume 5 - Springer, pp. 165-178.

Near-infrared reflectance of zunyite: implications for field mapping and remote-sensing detection of hydrothermally altered high alumina rocks.

USGS Publications Warehouse

Crowley, J.K.

1984-01-01

Several hydroxyl-bearing minerals have diagnostic absorption bands in the 2.0-2.4 mu m wave length range, and can be identified with an orbital radiometer and with high-resolution airborne and field portable spectrometers. Among such minerals, zunyite, 143Al13Si5O20(OH,F)18Cl, has distinctive spectral absorption characteristics and is notably restricted to, and thus an indicator mineral of, advanced argillic alteration. Although seldom noted because it visually resembles quartz, zunyite is probably not as rare as generally believed. Laboratory measurements and general considerations underlie suggestions favouring the feasibility of detecting zunyite, alone and in mixtures with other Al-OH minerals, using field portable spectrometers.-G.J.N.

3-D reservoir characterization of the House Creek oil field, Powder River Basin, Wyoming

USGS Publications Warehouse

Higley, Debra K.; Pantea, Michael P.; Slatt, Roger M.

1997-01-01

This CD-ROM is intended to serve a broad audience. An important purpose is to explain geologic and geochemical factors that control petroleum production from the House Creek Field. This information may serve as an analog for other marine-ridge sandstone reservoirs. The 3-D slide and movie images are tied to explanations and 2-D geologic and geochemical images to visualize geologic structures in three dimensions, explain the geologic significance of porosity/permeability distribution across the sandstone bodies, and tie this to petroleum production characteristics in the oil field. Movies, text, images including scanning electron photomicrographs (SEM), thin-section photomicrographs, and data files can be copied from the CD-ROM for use in external mapping, statistical, and other applications.

On that Note...

ERIC Educational Resources Information Center

Stein, Harry

1988-01-01

Provides suggestions for note-taking from books, lectures, visual presentations, and laboratory experiments to enhance student knowledge, memory, and length of attention span during instruction. Describes topical and structural outlines, visual mapping, charting, three-column note-taking, and concept mapping. Benefits and application of…

Multishot versus Single-Shot Pulse Sequences in Very High Field fMRI: A Comparison Using Retinotopic Mapping

PubMed Central

Gatenby, J. Christopher; Gore, John C.; Tong, Frank

2012-01-01

High-resolution functional MRI is a leading application for very high field (7 Tesla) human MR imaging. Though higher field strengths promise improvements in signal-to-noise ratios (SNR) and BOLD contrast relative to fMRI at 3 Tesla, these benefits may be partially offset by accompanying increases in geometric distortion and other off-resonance effects. Such effects may be especially pronounced with the single-shot EPI pulse sequences typically used for fMRI at standard field strengths. As an alternative, one might consider multishot pulse sequences, which may lead to somewhat lower temporal SNR than standard EPI, but which are also often substantially less susceptible to off-resonance effects. Here we consider retinotopic mapping of human visual cortex as a practical test case by which to compare examples of these sequence types for high-resolution fMRI at 7 Tesla. We performed polar angle retinotopic mapping at each of 3 isotropic resolutions (2.0, 1.7, and 1.1 mm) using both accelerated single-shot 2D EPI and accelerated multishot 3D gradient-echo pulse sequences. We found that single-shot EPI indeed led to greater temporal SNR and contrast-to-noise ratios (CNR) than the multishot sequences. However, additional distortion correction in postprocessing was required in order to fully realize these advantages, particularly at higher resolutions. The retinotopic maps produced by both sequence types were qualitatively comparable, and showed equivalent test/retest reliability. Thus, when surface-based analyses are planned, or in other circumstances where geometric distortion is of particular concern, multishot pulse sequences could provide a viable alternative to single-shot EPI. PMID:22514646

Multishot versus single-shot pulse sequences in very high field fMRI: a comparison using retinotopic mapping.

PubMed

Swisher, Jascha D; Sexton, John A; Gatenby, J Christopher; Gore, John C; Tong, Frank

2012-01-01

High-resolution functional MRI is a leading application for very high field (7 Tesla) human MR imaging. Though higher field strengths promise improvements in signal-to-noise ratios (SNR) and BOLD contrast relative to fMRI at 3 Tesla, these benefits may be partially offset by accompanying increases in geometric distortion and other off-resonance effects. Such effects may be especially pronounced with the single-shot EPI pulse sequences typically used for fMRI at standard field strengths. As an alternative, one might consider multishot pulse sequences, which may lead to somewhat lower temporal SNR than standard EPI, but which are also often substantially less susceptible to off-resonance effects. Here we consider retinotopic mapping of human visual cortex as a practical test case by which to compare examples of these sequence types for high-resolution fMRI at 7 Tesla. We performed polar angle retinotopic mapping at each of 3 isotropic resolutions (2.0, 1.7, and 1.1 mm) using both accelerated single-shot 2D EPI and accelerated multishot 3D gradient-echo pulse sequences. We found that single-shot EPI indeed led to greater temporal SNR and contrast-to-noise ratios (CNR) than the multishot sequences. However, additional distortion correction in postprocessing was required in order to fully realize these advantages, particularly at higher resolutions. The retinotopic maps produced by both sequence types were qualitatively comparable, and showed equivalent test/retest reliability. Thus, when surface-based analyses are planned, or in other circumstances where geometric distortion is of particular concern, multishot pulse sequences could provide a viable alternative to single-shot EPI.

Visualize Your Data with Google Fusion Tables

NASA Astrophysics Data System (ADS)

Brisbin, K. E.

2011-12-01

Google Fusion Tables is a modern data management platform that makes it easy to host, manage, collaborate on, visualize, and publish tabular data online. Fusion Tables allows users to upload their own data to the Google cloud, which they can then use to create compelling and interactive visualizations with the data. Users can view data on a Google Map, plot data in a line chart, or display data along a timeline. Users can share these visualizations with others to explore and discover interesting trends about various types of data, including scientific data such as invasive species or global trends in disease. Fusion Tables has been used by many organizations to visualize a variety of scientific data. One example is the California Redistricting Map created by the LA Times: http://goo.gl/gwZt5 The Pacific Institute and Circle of Blue have used Fusion Tables to map the quality of water around the world: http://goo.gl/T4SX8 The World Resources Institute mapped the threat level of coral reefs using Fusion Tables: http://goo.gl/cdqe8 What attendees will learn in this session: This session will cover all the steps necessary to use Fusion Tables to create a variety of interactive visualizations. Attendees will begin by learning about the various options for uploading data into Fusion Tables, including Shapefile, KML file, and CSV file import. Attendees will then learn how to use Fusion Tables to manage their data by merging it with other data and controlling the permissions of the data. Finally, the session will cover how to create a customized visualization from the data, and share that visualization with others using both Fusion Tables and the Google Maps API.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pucci, A.A. Jr.

Hydrogeologic maps are typical products of ground-water investigations. The features on these maps can be used by planning commissions to optimize land use. Planners could use confining-unit outcrop maps for siting landfills and hazardous material handling facilities. This paper examines ground-water chemistry from 53 wells, field measurements, hydrogeologic conditions from a quasi-3-D flow model for predevelopment (before 1900), and 1984 flow conditions, and evaluates relationships between them. Several recent reports have examined water quality in the area. The wells for this paper were screened in the Potomac-Raritan-Magothy aquifer system (PRMA) in the northern Coastal Plain of New Jersey in amore » 184 square mile area which is undergoing rapid growth. Hydrogeologic conditions considered include aquifer sampled, well location relative to flow-path distance from the outcrop, confining-unit thickness, and confining-unit vertical hydraulic conductivity (Kv). Visual, graphical and principal component analyses were used to evaluate the relationships.« less

Learning Building Layouts with Non-geometric Visual Information: The Effects of Visual Impairment and Age

PubMed Central

Kalia, Amy A.; Legge, Gordon E.; Giudice, Nicholas A.

2009-01-01

Previous studies suggest that humans rely on geometric visual information (hallway structure) rather than non-geometric visual information (e.g., doors, signs and lighting) for acquiring cognitive maps of novel indoor layouts. This study asked whether visual impairment and age affect reliance on non-geometric visual information for layout learning. We tested three groups of participants—younger (< 50 years) normally sighted, older (50–70 years) normally sighted, and low vision (people with heterogeneous forms of visual impairment ranging in age from 18–67). Participants learned target locations in building layouts using four presentation modes: a desktop virtual environment (VE) displaying only geometric cues (Sparse VE), a VE displaying both geometric and non-geometric cues (Photorealistic VE), a Map, and a Real building. Layout knowledge was assessed by map drawing and by asking participants to walk to specified targets in the real space. Results indicate that low-vision and older normally-sighted participants relied on additional non-geometric information to accurately learn layouts. In conclusion, visual impairment and age may result in reduced perceptual and/or memory processing that makes it difficult to learn layouts without non-geometric visual information. PMID:19189732

Remote sensing data applied to the evaluation of soil erosion caused by land-use. Ribeirao Anhumas Basin Area: A case study. [Brazil

NASA Technical Reports Server (NTRS)

Dejesusparada, N. (Principal Investigator); Dosanjosferreirapinto, S.; Kux, H. J. H.

1980-01-01

Formerly covered by a tropical forest, the study area was deforested in the early 40's for coffee plantation and cattle raising, which caused intense gully erosion problems. To develop a method to analyze the relationship between land use and soil erosion, visual interpretations of aerial photographs (scale 1:25.000), MSS-LANDSAT imagery (scale 1:250,000), as well as automatic interpretation of computer compatible tapes by IMAGE-100 system were carried out. From visual interpretation the following data were obtained: land use and cover tapes, slope classes, ravine frequency, and a texture sketch map. During field work, soil samples were collected for texture and X-ray analysis. The texture sketch map indicate that the areas with higher slope angles have a higher susceptibilty to the development of gullies. Also, the over carriage of pastureland, together with very friable lithologies (mainly sandstone) occuring in that area, seem to be the main factors influencing the catastrophic extension of ravines in the study site.

Acoustic Seafloor Classification near the Duanqiao hydrothermal field at the Southwest Indian Ridge from Multibeam Backscatter Data

NASA Astrophysics Data System (ADS)

Wang, A.; Tao, C.; Xu, Y.; Zhang, G.; Liao, S.

2016-12-01

The inactive Duanqiao hydrothermal field is located on the 50.5°E SWIR axial high with a shallow depth of about 1700 meters. Seafloor morphology of the area surrounding the field is relatively flat, which exerts less influence on multibeam backscatter data than rugged terrains do. Therefore, it is an ideal experimental area to conduct seafloor classification utilizing multibeam sonar. This paper dealt with a backscatter analysis of Simrad EM120 multibeam sonar data, acquired during the Chinese DY115-34 cruise near the Duanqiao hydrothermal field, and comprehensively studied types and distribution characteristics of seafloor substrate by combining with visual interpretations and TV-Grab Samples. Firstly, a mosaic was built to analyze backscatter distribution after multibeam backscatter data were fully processed using Geocoder engine on CARIS HIPS&SIPS software. Prior information was gained by analyzing the link between the processed backscatter data and the visual interpretations of two deep-tow video survey lines. Among the two survey lines, one corresponds to sediment-dominated seafloor and the other corresponds to pillow basalt-dominated seafloor. Then, backscatter data of the mosaic were classified statistically to identify three types of seafloor: soft substrate, medium-hard substrate and hard substrate. Compared with visual interpretations and TV-Grab Samples, these three seafloor types were interpreted as sediment, breccia and pillow basalt, respectively. Finally, a seafloor classification map was generated. According to the results, we discovered two distinguished distribution characteristics of seafloor substrate: 1. there is a transition from pillow basalt-dominated seafloor to sediment-dominated seafloor away from the SWIR axis; 2. the Duanqiao hydrothermal field is mostly outcropped by pillow basalts and locally covered by breccias and sediments, the reason of which is probably that this field is a relatively recent volcanic area.

Representation and disconnection in imaginal neglect.

PubMed

Rode, G; Cotton, F; Revol, P; Jacquin-Courtois, S; Rossetti, Y; Bartolomeo, P

2010-08-01

Patients with neglect failure to detect, orient, or respond to stimuli from a spatially confined region, usually on their left side. Often, the presence of perceptual input increases left omissions, while sensory deprivation decreases them, possibly by removing attention-catching right-sided stimuli (Bartolomeo, 2007). However, such an influence of visual deprivation on representational neglect was not observed in patients while they were imagining a map of France (Rode et al., 2007). Therefore, these patients with imaginal neglect either failed to generate the left side of mental images (Bisiach & Luzzatti, 1978), or suffered from a co-occurrence of deficits in automatic (bottom-up) and voluntary (top-down) orienting of attention. However, in Rode et al.'s experiment visual input was not directly relevant to the task; moreover, distraction from visual input might primarily manifest itself when representation guides somatomotor actions, beyond those involved in the generation and mental exploration of an internal map (Thomas, 1999). To explore these possibilities, we asked a patient with right hemisphere damage, R.D., to explore visual and imagined versions of a map of France in three conditions: (1) 'imagine the map in your mind' (imaginal); (2) 'describe a real map' (visual); and (3) 'list the names of French towns' (propositional). For the imaginal and visual conditions, verbal and manual pointing responses were collected; the task was also given before and after mental rotation of the map by 180 degrees . R.D. mentioned more towns on the right side of the map in the imaginal and visual conditions, but showed no representational deficit in the propositional condition. The rightward inner exploration bias in the imaginal and visual conditions was similar in magnitude and was not influenced by mental rotation or response type (verbal responses or manual pointing to locations on a map), thus suggesting that the representational deficit was robust and independent of perceptual input in R.D. Structural and diffusion MRI demonstrated damage to several white matter tracts in the right hemisphere and to the splenium of corpus callosum. A second right-brain damaged patient (P.P.), who showed signs of visual but not imaginal neglect, had damage to the same intra-hemispheric tracts, but the callosal connections were spared. Imaginal neglect in R.D. may result from fronto-parietal dysfunction impairing orientation towards left-sided items and posterior callosal disconnection preventing the symmetrical processing of spatial information from long-term memory. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

fMRI evidence for sensorimotor transformations in human cortex during smooth pursuit eye movements.

PubMed

Kimmig, H; Ohlendorf, S; Speck, O; Sprenger, A; Rutschmann, R M; Haller, S; Greenlee, M W

2008-01-01

Smooth pursuit eye movements (SP) are driven by moving objects. The pursuit system processes the visual input signals and transforms this information into an oculomotor output signal. Despite the object's movement on the retina and the eyes' movement in the head, we are able to locate the object in space implying coordinate transformations from retinal to head and space coordinates. To test for the visual and oculomotor components of SP and the possible transformation sites, we investigated three experimental conditions: (I) fixation of a stationary target with a second target moving across the retina (visual), (II) pursuit of the moving target with the second target moving in phase (oculomotor), (III) pursuit of the moving target with the second target remaining stationary (visuo-oculomotor). Precise eye movement data were simultaneously measured with the fMRI data. Visual components of activation during SP were located in the motion-sensitive, temporo-parieto-occipital region MT+ and the right posterior parietal cortex (PPC). Motor components comprised more widespread activation in these regions and additional activations in the frontal and supplementary eye fields (FEF, SEF), the cingulate gyrus and precuneus. The combined visuo-oculomotor stimulus revealed additional activation in the putamen. Possible transformation sites were found in MT+ and PPC. The MT+ activation evoked by the motion of a single visual dot was very localized, while the activation of the same single dot motion driving the eye was rather extended across MT+. The eye movement information appeared to be dispersed across the visual map of MT+. This could be interpreted as a transfer of the one-dimensional eye movement information into the two-dimensional visual map. Potentially, the dispersed information could be used to remap MT+ to space coordinates rather than retinal coordinates and to provide the basis for a motor output control. A similar interpretation holds for our results in the PPC region.

ClimatePipes: User-Friendly Data Access, Manipulation, Analysis & Visualization of Community Climate Models

NASA Astrophysics Data System (ADS)

Chaudhary, A.; DeMarle, D.; Burnett, B.; Harris, C.; Silva, W.; Osmari, D.; Geveci, B.; Silva, C.; Doutriaux, C.; Williams, D. N.

2013-12-01

The impact of climate change will resonate through a broad range of fields including public health, infrastructure, water resources, and many others. Long-term coordinated planning, funding, and action are required for climate change adaptation and mitigation. Unfortunately, widespread use of climate data (simulated and observed) in non-climate science communities is impeded by factors such as large data size, lack of adequate metadata, poor documentation, and lack of sufficient computational and visualization resources. We present ClimatePipes to address many of these challenges by creating an open source platform that provides state-of-the-art, user-friendly data access, analysis, and visualization for climate and other relevant geospatial datasets, making the climate data available to non-researchers, decision-makers, and other stakeholders. The overarching goals of ClimatePipes are: - Enable users to explore real-world questions related to climate change. - Provide tools for data access, analysis, and visualization. - Facilitate collaboration by enabling users to share datasets, workflows, and visualization. ClimatePipes uses a web-based application platform for its widespread support on mainstream operating systems, ease-of-use, and inherent collaboration support. The front-end of ClimatePipes uses HTML5 (WebGL, Canvas2D, CSS3) to deliver state-of-the-art visualization and to provide a best-in-class user experience. The back-end of the ClimatePipes is built around Python using the Visualization Toolkit (VTK, http://vtk.org), Climate Data Analysis Tools (CDAT, http://uv-cdat.llnl.gov), and other climate and geospatial data processing tools such as GDAL and PROJ4. ClimatePipes web-interface to query and access data from remote sources (such as ESGF). Shown in the figure is climate data layer from ESGF on top of map data layer from OpenStreetMap. The ClimatePipes workflow editor provides flexibility and fine grained control, and uses the VisTrails (http://www.vistrails.org) workflow engine in the backend.

Polarization imaging of imperfect m-plane GaN surfaces

NASA Astrophysics Data System (ADS)

Sakai, Yuji; Kawayama, Iwao; Nakanishi, Hidetoshi; Tonouchi, Masayoshi

2017-04-01

Surface polar states in m-plane GaN wafers were studied using a laser terahertz (THz) emission microscope (LTEM). Femtosecond laser illumination excites THz waves from the surface due to photocarrier acceleration by local spontaneous polarization and/or the surface built-in electric field. The m-plane, in general, has a large number of unfavorable defects and unintentional polarization inversion created during the regrowth process. The LTEM images can visualize surface domains with different polarizations, some of which are hard to visualize with photoluminescence mapping, i.e., non-radiative defect areas. The present study demonstrates that the LTEM provides rich information about the surface polar states of GaN, which is crucial to improve the performance of GaN-based optoelectronic and power devices.

Investigating the Use of 3d Geovisualizations for Urban Design in Informal Settlement Upgrading in South Africa

NASA Astrophysics Data System (ADS)

Rautenbach, V.; Coetzee, S.; Çöltekin, A.

2016-06-01

Informal settlements are a common occurrence in South Africa, and to improve in-situ circumstances of communities living in informal settlements, upgrades and urban design processes are necessary. Spatial data and maps are essential throughout these processes to understand the current environment, plan new developments, and communicate the planned developments. All stakeholders need to understand maps to actively participate in the process. However, previous research demonstrated that map literacy was relatively low for many planning professionals in South Africa, which might hinder effective planning. Because 3D visualizations resemble the real environment more than traditional maps, many researchers posited that they would be easier to interpret. Thus, our goal is to investigate the effectiveness of 3D geovisualizations for urban design in informal settlement upgrading in South Africa. We consider all involved processes: 3D modelling, visualization design, and cognitive processes during map reading. We found that procedural modelling is a feasible alternative to time-consuming manual modelling, and can produce high quality models. When investigating the visualization design, the visual characteristics of 3D models and relevance of a subset of visual variables for urban design activities of informal settlement upgrades were qualitatively assessed. The results of three qualitative user experiments contributed to understanding the impact of various levels of complexity in 3D city models and map literacy of future geoinformatics and planning professionals when using 2D maps and 3D models. The research results can assist planners in designing suitable 3D models that can be used throughout all phases of the process.

Biological Parametric Mapping: A Statistical Toolbox for Multi-Modality Brain Image Analysis

PubMed Central

Casanova, Ramon; Ryali, Srikanth; Baer, Aaron; Laurienti, Paul J.; Burdette, Jonathan H.; Hayasaka, Satoru; Flowers, Lynn; Wood, Frank; Maldjian, Joseph A.

2006-01-01

In recent years multiple brain MR imaging modalities have emerged; however, analysis methodologies have mainly remained modality specific. In addition, when comparing across imaging modalities, most researchers have been forced to rely on simple region-of-interest type analyses, which do not allow the voxel-by-voxel comparisons necessary to answer more sophisticated neuroscience questions. To overcome these limitations, we developed a toolbox for multimodal image analysis called biological parametric mapping (BPM), based on a voxel-wise use of the general linear model. The BPM toolbox incorporates information obtained from other modalities as regressors in a voxel-wise analysis, thereby permitting investigation of more sophisticated hypotheses. The BPM toolbox has been developed in MATLAB with a user friendly interface for performing analyses, including voxel-wise multimodal correlation, ANCOVA, and multiple regression. It has a high degree of integration with the SPM (statistical parametric mapping) software relying on it for visualization and statistical inference. Furthermore, statistical inference for a correlation field, rather than a widely-used T-field, has been implemented in the correlation analysis for more accurate results. An example with in-vivo data is presented demonstrating the potential of the BPM methodology as a tool for multimodal image analysis. PMID:17070709

Mapping of Sample Collection Data: GIS Tools for the Natural Product Researcher

PubMed Central

Oberlies, Nicholas H.; Rineer, James I.; Alali, Feras Q.; Tawaha, Khaled; Falkinham, Joseph O.; Wheaton, William D.

2009-01-01

Scientists engaged in the research of natural products often either conduct field collections themselves or collaborate with partners who do, such as botanists, mycologists, or SCUBA divers. The information gleaned from such collecting trips (e.g. longitude/latitude coordinates, geography, elevation, and a multitude of other field observations) have provided valuable data to the scientific community (e.g., biodiversity), even if it is tangential to the direct aims of the natural products research, which are often focused on drug discovery and/or chemical ecology. Geographic Information Systems (GIS) have been used to display, manage, and analyze geographic data, including collection sites for natural products. However, to the uninitiated, these tools are often beyond the financial and/or computational means of the natural product scientist. With new, free, and easy-to-use geospatial visualization tools, such as Google Earth, mapping and geographic imaging of sampling data are now within the reach of natural products scientists. The goals of the present study were to develop simple tools that are tailored for the natural products setting, thereby presenting a means to map such information, particularly via open source software like Google Earth. PMID:20161345

Evolution of attention mechanisms for early visual processing

NASA Astrophysics Data System (ADS)

Müller, Thomas; Knoll, Alois

2011-03-01

Early visual processing as a method to speed up computations on visual input data has long been discussed in the computer vision community. The general target of a such approaches is to filter nonrelevant information from the costly higher-level visual processing algorithms. By insertion of this additional filter layer the overall approach can be speeded up without actually changing the visual processing methodology. Being inspired by the layered architecture of the human visual processing apparatus, several approaches for early visual processing have been recently proposed. Most promising in this field is the extraction of a saliency map to determine regions of current attention in the visual field. Such saliency can be computed in a bottom-up manner, i.e. the theory claims that static regions of attention emerge from a certain color footprint, and dynamic regions of attention emerge from connected blobs of textures moving in a uniform way in the visual field. Top-down saliency effects are either unconscious through inherent mechanisms like inhibition-of-return, i.e. within a period of time the attention level paid to a certain region automatically decreases if the properties of that region do not change, or volitional through cognitive feedback, e.g. if an object moves consistently in the visual field. These bottom-up and top-down saliency effects have been implemented and evaluated in a previous computer vision system for the project JAST. In this paper an extension applying evolutionary processes is proposed. The prior vision system utilized multiple threads to analyze the regions of attention delivered from the early processing mechanism. Here, in addition, multiple saliency units are used to produce these regions of attention. All of these saliency units have different parameter-sets. The idea is to let the population of saliency units create regions of attention, then evaluate the results with cognitive feedback and finally apply the genetic mechanism: mutation and cloning of the best performers and extinction of the worst performers considering computation of regions of attention. A fitness function can be derived by evaluating, whether relevant objects are found in the regions created. It can be seen from various experiments, that the approach significantly speeds up visual processing, especially regarding robust ealtime object recognition, compared to an approach not using saliency based preprocessing. Furthermore, the evolutionary algorithm improves the overall performance of the preprocessing system in terms of quality, as the system automatically and autonomously tunes the saliency parameters. The computational overhead produced by periodical clone/delete/mutation operations can be handled well within the realtime constraints of the experimental computer vision system. Nevertheless, limitations apply whenever the visual field does not contain any significant saliency information for some time, but the population still tries to tune the parameters - overfitting avoids generalization in this case and the evolutionary process may be reset by manual intervention.

TIES that BIND: an introduction to domain mapping as a visualization tool for virtual rehabilitation.

PubMed

Weiss, Patrice L Tamar; Kedar, Rochelle; Shahar, Meir

2006-04-01

The application of virtual reality (VR) to rehabilitation is a young, interdisciplinary field where clinical implementation very rapidly follows scientific discovery and technological advancement. Implementation is often so rapid that demonstration of intervention efficacy by investigators, and establishment of research and development priorities by funding bodies tend to be more reactive than proactive. An examination of the dynamic unfolding of the history of our young discipline may help us recognize the facilitators of current practice and identify the barriers that limit greater progress. This paper presents a first step towards the examination of the past and future growth of VR-based rehabilitation by presenting the use of concept maps to explore the publication history of application of VR to rehabilitation.

The Cosmic V-Web

NASA Astrophysics Data System (ADS)

Pomarède, Daniel; Hoffman, Yehuda; Courtois, Hélène M.; Tully, R. Brent

2017-08-01

The network of filaments with embedded clusters surrounding voids, which has been seen in maps derived from redshift surveys and reproduced in simulations, has been referred to as the cosmic web. A complementary description is provided by considering the shear in the velocity field of galaxies. The eigenvalues of the shear provide information regarding whether or not a region is collapsing in three dimensions, which is the condition for a knot, expanding in three dimensions, which is the condition for a void, or in the intermediate condition of a filament or sheet. The structures that are quantitatively defined by the eigenvalues can be approximated by iso-contours that provide a visual representation of the cosmic velocity (V) web. The current application is based on radial peculiar velocities from the Cosmicflows-2 collection of distances. The three-dimensional velocity field is constructed using the Wiener filter methodology in the linear approximation. Eigenvalues of the velocity shear are calculated at each point on a grid. Here, knots and filaments are visualized across a local domain of diameter ˜ 0.1c.

Mapping of mosquito breeding sites in malaria endemic areas in Pos Lenjang, Kuala Lipis, Pahang, Malaysia.

PubMed

Ahmad, Rohani; Ali, Wan N W M; Nor, Zurainee M; Ismail, Zamree; Hadi, Azahari A; Ibrahim, Mohd N; Lim, Lee H

2011-12-13

The application of the Geographic Information Systems (GIS) to the study of vector transmitted diseases considerably improves the management of the information obtained from the field survey and facilitates the study of the distribution patterns of the vector species. As part of a study to assess remote sensing data as a tool for vector mapping, geographical features like rivers, small streams, forest, roads and residential area were digitized from the satellite images and overlaid with entomological data. Map of larval breeding habitats distribution and map of malaria transmission risk area were developed using a combination of field data, satellite image analysis and GIS technique. All digital data in the GIS were displayed in the WGS 1984 coordinate system. Six occasions of larval surveillance were also conducted to determine the species of mosquitoes, their characteristics and the abundance of habitats. Larval survey studies showed that anopheline and culicine larvae were collected and mapped from 79 and 67 breeding sites respectively. Breeding habitats were located at 100-400 m from human settlement. Map of villages with 400 m buffer zone visualizes that more than 80% of Anopheles maculatus s.s. immature habitats were found within the buffer zone. This study amplifies the need for a broadening of the GIS approach which is emphasized with the aim of rejuvenating the dynamic aspect of entomological studies in Malaysia. In fact, the use of such basic GIS platforms promote a more rational basis for strategic planning and management in the control of endemic diseases at the national level.

Mapping of mosquito breeding sites in malaria endemic areas in Pos Lenjang, Kuala Lipis, Pahang, Malaysia

PubMed Central

2011-01-01

Background The application of the Geographic Information Systems (GIS) to the study of vector transmitted diseases considerably improves the management of the information obtained from the field survey and facilitates the study of the distribution patterns of the vector species. Methods As part of a study to assess remote sensing data as a tool for vector mapping, geographical features like rivers, small streams, forest, roads and residential area were digitized from the satellite images and overlaid with entomological data. Map of larval breeding habitats distribution and map of malaria transmission risk area were developed using a combination of field data, satellite image analysis and GIS technique. All digital data in the GIS were displayed in the WGS 1984 coordinate system. Six occasions of larval surveillance were also conducted to determine the species of mosquitoes, their characteristics and the abundance of habitats. Results Larval survey studies showed that anopheline and culicine larvae were collected and mapped from 79 and 67 breeding sites respectively. Breeding habitats were located at 100-400 m from human settlement. Map of villages with 400 m buffer zone visualizes that more than 80% of Anopheles maculatus s.s. immature habitats were found within the buffer zone. Conclusions This study amplifies the need for a broadening of the GIS approach which is emphasized with the aim of rejuvenating the dynamic aspect of entomological studies in Malaysia. In fact, the use of such basic GIS platforms promote a more rational basis for strategic planning and management in the control of endemic diseases at the national level. PMID:22166101

Development of Maps of Simple and Complex Cells in the Primary Visual Cortex

PubMed Central

Antolík, Ján; Bednar, James A.

2011-01-01

Hubel and Wiesel (1962) classified primary visual cortex (V1) neurons as either simple, with responses modulated by the spatial phase of a sine grating, or complex, i.e., largely phase invariant. Much progress has been made in understanding how simple-cells develop, and there are now detailed computational models establishing how they can form topographic maps ordered by orientation preference. There are also models of how complex cells can develop using outputs from simple cells with different phase preferences, but no model of how a topographic orientation map of complex cells could be formed based on the actual connectivity patterns found in V1. Addressing this question is important, because the majority of existing developmental models of simple-cell maps group neurons selective to similar spatial phases together, which is contrary to experimental evidence, and makes it difficult to construct complex cells. Overcoming this limitation is not trivial, because mechanisms responsible for map development drive receptive fields (RF) of nearby neurons to be highly correlated, while co-oriented RFs of opposite phases are anti-correlated. In this work, we model V1 as two topographically organized sheets representing cortical layer 4 and 2/3. Only layer 4 receives direct thalamic input. Both sheets are connected with narrow feed-forward and feedback connectivity. Only layer 2/3 contains strong long-range lateral connectivity, in line with current anatomical findings. Initially all weights in the model are random, and each is modified via a Hebbian learning rule. The model develops smooth, matching, orientation preference maps in both sheets. Layer 4 units become simple cells, with phase preference arranged randomly, while those in layer 2/3 are primarily complex cells. To our knowledge this model is the first explaining how simple cells can develop with random phase preference, and how maps of complex cells can develop, using only realistic patterns of connectivity. PMID:21559067

Ergodic theory and visualization. II. Fourier mesochronic plots visualize (quasi)periodic sets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Levnajić, Zoran; Department of Mechanical Engineering, University of California Santa Barbara, Santa Barbara, California 93106; Mezić, Igor

We present an application and analysis of a visualization method for measure-preserving dynamical systems introduced by I. Mezić and A. Banaszuk [Physica D 197, 101 (2004)], based on frequency analysis and Koopman operator theory. This extends our earlier work on visualization of ergodic partition [Z. Levnajić and I. Mezić, Chaos 20, 033114 (2010)]. Our method employs the concept of Fourier time average [I. Mezić and A. Banaszuk, Physica D 197, 101 (2004)], and is realized as a computational algorithms for visualization of periodic and quasi-periodic sets in the phase space. The complement of periodic phase space partition contains chaotic zone,more » and we show how to identify it. The range of method's applicability is illustrated using well-known Chirikov standard map, while its potential in illuminating higher-dimensional dynamics is presented by studying the Froeschlé map and the Extended Standard Map.« less

Ergodic theory and visualization. II. Fourier mesochronic plots visualize (quasi)periodic sets.

PubMed

Levnajić, Zoran; Mezić, Igor

2015-05-01

We present an application and analysis of a visualization method for measure-preserving dynamical systems introduced by I. Mezić and A. Banaszuk [Physica D 197, 101 (2004)], based on frequency analysis and Koopman operator theory. This extends our earlier work on visualization of ergodic partition [Z. Levnajić and I. Mezić, Chaos 20, 033114 (2010)]. Our method employs the concept of Fourier time average [I. Mezić and A. Banaszuk, Physica D 197, 101 (2004)], and is realized as a computational algorithms for visualization of periodic and quasi-periodic sets in the phase space. The complement of periodic phase space partition contains chaotic zone, and we show how to identify it. The range of method's applicability is illustrated using well-known Chirikov standard map, while its potential in illuminating higher-dimensional dynamics is presented by studying the Froeschlé map and the Extended Standard Map.

Visualizing Article Similarities via Sparsified Article Network and Map Projection for Systematic Reviews.

PubMed

Ji, Xiaonan; Machiraju, Raghu; Ritter, Alan; Yen, Po-Yin

2017-01-01

Systematic Reviews (SRs) of biomedical literature summarize evidence from high-quality studies to inform clinical decisions, but are time and labor intensive due to the large number of article collections. Article similarities established from textual features have been shown to assist in the identification of relevant articles, thus facilitating the article screening process efficiently. In this study, we visualized article similarities to extend its utilization in practical settings for SR researchers, aiming to promote human comprehension of article distributions and hidden patterns. To prompt an effective visualization in an interpretable, intuitive, and scalable way, we implemented a graph-based network visualization with three network sparsification approaches and a distance-based map projection via dimensionality reduction. We evaluated and compared three network sparsification approaches and the visualization types (article network vs. article map). We demonstrated the effectiveness in revealing article distribution and exhibiting clustering patterns of relevant articles with practical meanings for SRs.

Automatic face recognition in HDR imaging

NASA Astrophysics Data System (ADS)

Pereira, Manuela; Moreno, Juan-Carlos; Proença, Hugo; Pinheiro, António M. G.

2014-05-01

The gaining popularity of the new High Dynamic Range (HDR) imaging systems is raising new privacy issues caused by the methods used for visualization. HDR images require tone mapping methods for an appropriate visualization on conventional and non-expensive LDR displays. These visualization methods might result in completely different visualization raising several issues on privacy intrusion. In fact, some visualization methods result in a perceptual recognition of the individuals, while others do not even show any identity. Although perceptual recognition might be possible, a natural question that can rise is how computer based recognition will perform using tone mapping generated images? In this paper, a study where automatic face recognition using sparse representation is tested with images that result from common tone mapping operators applied to HDR images. Its ability for the face identity recognition is described. Furthermore, typical LDR images are used for the face recognition training.

Automatic estimation of retinal nerve fiber bundle orientation in SD-OCT images using a structure-oriented smoothing filter

NASA Astrophysics Data System (ADS)

Ghafaryasl, Babak; Baart, Robert; de Boer, Johannes F.; Vermeer, Koenraad A.; van Vliet, Lucas J.

2017-02-01

Optical coherence tomography (OCT) yields high-resolution, three-dimensional images of the retina. A better understanding of retinal nerve fiber bundle (RNFB) trajectories in combination with visual field data may be used for future diagnosis and monitoring of glaucoma. However, manual tracing of these bundles is a tedious task. In this work, we present an automatic technique to estimate the orientation of RNFBs from volumetric OCT scans. Our method consists of several steps, starting from automatic segmentation of the RNFL. Then, a stack of en face images around the posterior nerve fiber layer interface was extracted. The image showing the best visibility of RNFB trajectories was selected for further processing. After denoising the selected en face image, a semblance structure-oriented filter was applied to probe the strength of local linear structure in a discrete set of orientations creating an orientation space. Gaussian filtering along the orientation axis in this space is used to find the dominant orientation. Next, a confidence map was created to supplement the estimated orientation. This confidence map was used as pixel weight in normalized convolution to regularize the semblance filter response after which a new orientation estimate can be obtained. Finally, after several iterations an orientation field corresponding to the strongest local orientation was obtained. The RNFB orientations of six macular scans from three subjects were estimated. For all scans, visual inspection shows a good agreement between the estimated orientation fields and the RNFB trajectories in the en face images. Additionally, a good correlation between the orientation fields of two scans of the same subject was observed. Our method was also applied to a larger field of view around the macula. Manual tracing of the RNFB trajectories shows a good agreement with the automatically obtained streamlines obtained by fiber tracking.

Automated grain mapping using wide angle convergent beam electron diffraction in transmission electron microscope for nanomaterials.

PubMed

Kumar, Vineet

2011-12-01

The grain size statistics, commonly derived from the grain map of a material sample, are important microstructure characteristics that greatly influence its properties. The grain map for nanomaterials is usually obtained manually by visual inspection of the transmission electron microscope (TEM) micrographs because automated methods do not perform satisfactorily. While the visual inspection method provides reliable results, it is a labor intensive process and is often prone to human errors. In this article, an automated grain mapping method is developed using TEM diffraction patterns. The presented method uses wide angle convergent beam diffraction in the TEM. The automated technique was applied on a platinum thin film sample to obtain the grain map and subsequently derive grain size statistics from it. The grain size statistics obtained with the automated method were found in good agreement with the visual inspection method.

Land use and land cover (LULC) of the Republic of the Maldives: first national map and LULC change analysis using remote-sensing data.

PubMed

Fallati, Luca; Savini, Alessandra; Sterlacchini, Simone; Galli, Paolo

2017-08-01

The Maldives islands in recent decades have experienced dramatic land-use change. Uninhabited islands were turned into new resort islands; evergreen tropical forests were cut, to be replaced by fields and new built-up areas. All these changes happened without a proper monitoring and urban planning strategy from the Maldivian government due to the lack of national land-use and land-cover (LULC) data. This study aimed to realize the first land-use map of the entire Maldives archipelago and to detect land-use and land-cover change (LULCC) using high-resolution satellite images and socioeconomic data. Due to the peculiar geographic and environmental features of the archipelago, the land-use map was obtained by visual interpretation and manual digitization of land-use patches. The images used, dated 2011, were obtained from Digital Globe's WorldView 1 and WorldView 2 satellites. Nine land-use classes and 18 subclasses were identified and mapped. During a field survey, ground control points were collected to test the geographic and thematic accuracy of the land-use map. The final product's overall accuracy was 85%. Once the accuracy of the map had been checked, LULCC maps were created using images from the early 2000s derived from Google Earth historical imagery. Post-classification comparison of the classified maps showed that growth of built-up and agricultural areas resulted in decreases in forest land and shrubland. The LULCC maps also revealed an increase in land reclamation inside lagoons near inhabited islands, resulting in environmental impacts on fragile reef habitat. The LULC map of the Republic of the Maldives produced in this study can be used by government authorities to make sustainable land-use planning decisions and to provide better management of land use and land cover.

Impaired letter-string processing in developmental dyslexia: what visual-to-phonology code mapping disorder?

PubMed

Valdois, Sylviane; Lassus-Sangosse, Delphine; Lobier, Muriel

2012-05-01

Poor parallel letter-string processing in developmental dyslexia was taken as evidence of poor visual attention (VA) span, that is, a limitation of visual attentional resources that affects multi-character processing. However, the use of letter stimuli in oral report tasks was challenged on its capacity to highlight a VA span disorder. In particular, report of poor letter/digit-string processing but preserved symbol-string processing was viewed as evidence of poor visual-to-phonology code mapping, in line with the phonological theory of developmental dyslexia. We assessed here the visual-to-phonological-code mapping disorder hypothesis. In Experiment 1, letter-string, digit-string and colour-string processing was assessed to disentangle a phonological versus visual familiarity account of the letter/digit versus symbol dissociation. Against a visual-to-phonological-code mapping disorder but in support of a familiarity account, results showed poor letter/digit-string processing but preserved colour-string processing in dyslexic children. In Experiment 2, two tasks of letter-string report were used, one of which was performed simultaneously to a high-taxing phonological task. Results show that dyslexic children are similarly impaired in letter-string report whether a concurrent phonological task is simultaneously performed or not. Taken together, these results provide strong evidence against a phonological account of poor letter-string processing in developmental dyslexia. Copyright © 2012 John Wiley & Sons, Ltd.

Exploring Modality Compatibility in the Response-Effect Compatibility Paradigm.

PubMed

Földes, Noémi; Philipp, Andrea M; Badets, Arnaud; Koch, Iring

2017-01-01

According to ideomotor theory , action planning is based on anticipatory perceptual representations of action-effects. This aspect of action control has been investigated in studies using the response-effect compatibility (REC) paradigm, in which responses have been shown to be facilitated if ensuing perceptual effects share codes with the response based on dimensional overlap (i.e., REC). Additionally, according to the notion of ideomotor compatibility, certain response-effect (R-E) mappings will be stronger than others because some response features resemble the anticipated sensory response effects more strongly than others (e.g., since vocal responses usually produce auditory effects, an auditory stimulus should be anticipated in a stronger manner following vocal responses rather than following manual responses). Yet, systematic research on this matter is lacking. In the present study, two REC experiments aimed to explore the influence of R-E modality mappings. In Experiment 1, vocal number word responses produced visual effects on the screen (digits vs. number words; i.e., visual-symbolic vs. visual-verbal effect codes). The REC effect was only marginally larger for visual-verbal than for visual-symbolic effects. Using verbal effect codes in Experiment 2, we found that the REC effect was larger with auditory-verbal R-E mapping than with visual-verbal R-E mapping. Overall, the findings support the hypothesis of a role of R-E modality mappings in REC effects, suggesting both further evidence for ideomotor accounts as well as code-specific and modality-specific contributions to effect anticipation.

Functional MRI mapping of visual function and selective attention for performance assessment and presurgical planning using conjunctive visual search.

PubMed

Parker, Jason G; Zalusky, Eric J; Kirbas, Cemil

2014-03-01

Accurate mapping of visual function and selective attention using fMRI is important in the study of human performance as well as in presurgical treatment planning of lesions in or near visual centers of the brain. Conjunctive visual search (CVS) is a useful tool for mapping visual function during fMRI because of its greater activation extent compared with high-capacity parallel search processes. The purpose of this work was to develop and evaluate a CVS that was capable of generating consistent activation in the basic and higher level visual areas of the brain by using a high number of distractors as well as an optimized contrast condition. Images from 10 healthy volunteers were analyzed and brain regions of greatest activation and deactivation were determined using a nonbiased decomposition of the results at the hemisphere, lobe, and gyrus levels. The results were quantified in terms of activation and deactivation extent and mean z-statistic. The proposed CVS was found to generate robust activation of the occipital lobe, as well as regions in the middle frontal gyrus associated with coordinating eye movements and in regions of the insula associated with task-level control and focal attention. As expected, the task demonstrated deactivation patterns commonly implicated in the default-mode network. Further deactivation was noted in the posterior region of the cerebellum, most likely associated with the formation of optimal search strategy. We believe the task will be useful in studies of visual and selective attention in the neuroscience community as well as in mapping visual function in clinical fMRI.

Mapping the Challenges of Magnesium Battery.

PubMed

Song, Jaehee; Sahadeo, Emily; Noked, Malachi; Lee, Sang Bok

2016-05-05

Rechargeable Mg battery has been considered a major candidate as a beyond lithium ion battery technology, which is apparent through the tremendous works done in the field over the past decades. The challenges for realization of Mg battery are complicated, multidisciplinary, and the tremendous work done to overcome these challenges is very hard to organize in a regular review paper. Additionally, we claim that organization of the huge amount of information accumulated by the great scientific progress achieved by various groups in the field will shed the light on the unexplored research domains and give clear perspectives and guidelines for next breakthrough to take place. In this Perspective, we provide a convenient map of Mg battery research in a form of radar chart of Mg electrolytes, which evaluates the electrolyte under the important components of Mg batteries. The presented radar charts visualize the accumulated knowledge on Mg battery and allow for navigation of not only the current research state but also future perspective of Mg battery at a glance.

Analyzing the research in Integrative & Complementary Medicine by means of science mapping.

PubMed

Moral-Muñoz, J A; Cobo, M J; Peis, E; Arroyo-Morales, M; Herrera-Viedma, E

2014-04-01

The research in the Complementary and Alternative Medicine (CAM) field is analyzed according to the journals indexed in ISI Web of Science. Science Mapping Analysis (SMA) is used to provide and overview of the conceptual evolution of the CAM field. The software SciMAT is used to detect and visualize the hidden themes and their evolution over a consecutive span of years. It combines SMA and performance analysis. Twenty one journals related to CAM were analyzed, in four consecutive periods from 1974 to 2011. Strategic diagrams and the thematic evolution of CAM, together with performance indicators (h-index), were obtained. The results show that CAM research has focused on seven main thematic areas: MEDICINAL-PLANTS, CHIROPRACTIC-AND-LOW-BACK-PAIN, ACUPUNCTURE-AND-PAIN, CELL-PROCESSES-AND-DISEASES, LIPID-PEROXIDATION and DIABETES-AND-INSULIN. The research output could be used by the scientific community to identify thematic areas on which interest is focused. Copyright © 2014 Elsevier Ltd. All rights reserved.

Building a virtual archive using brain architecture and Web 3D to deliver neuropsychopharmacology content over the Internet.

PubMed

Mongeau, R; Casu, M A; Pani, L; Pillolla, G; Lianas, L; Giachetti, A

2008-05-01

The vast amount of heterogeneous data generated in various fields of neurosciences such as neuropsychopharmacology can hardly be classified using traditional databases. We present here the concept of a virtual archive, spatially referenced over a simplified 3D brain map and accessible over the Internet. A simple prototype (available at http://aquatics.crs4.it/neuropsydat3d) has been realized using current Web-based virtual reality standards and technologies. It illustrates how primary literature or summary information can easily be retrieved through hyperlinks mapped onto a 3D schema while navigating through neuroanatomy. Furthermore, 3D navigation and visualization techniques are used to enhance the representation of brain's neurotransmitters, pathways and the involvement of specific brain areas in any particular physiological or behavioral functions. The system proposed shows how the use of a schematic spatial organization of data, widely exploited in other fields (e.g. Geographical Information Systems) can be extremely useful to develop efficient tools for research and teaching in neurosciences.

Anticipatory Attentional Suppression of Visual Features Indexed by Oscillatory Alpha-Band Power Increases: A High-Density Electrical Mapping Study

PubMed Central

Snyder, Adam C.; Foxe, John J.

2010-01-01

Retinotopically specific increases in alpha-band (~10 Hz) oscillatory power have been strongly implicated in the suppression of processing for irrelevant parts of the visual field during the deployment of visuospatial attention. Here, we asked whether this alpha suppression mechanism also plays a role in the nonspatial anticipatory biasing of feature-based attention. Visual word cues informed subjects what the task-relevant feature of an upcoming visual stimulus (S2) was, while high-density electroencephalographic recordings were acquired. We examined anticipatory oscillatory activity in the Cue-to-S2 interval (~2 s). Subjects were cued on a trial-by-trial basis to attend to either the color or direction of motion of an upcoming dot field array, and to respond when they detected that a subset of the dots differed from the majority along the target feature dimension. We used the features of color and motion, expressly because they have well known, spatially separated cortical processing areas, to distinguish shifts in alpha power over areas processing each feature. Alpha power from dorsal regions increased when motion was the irrelevant feature (i.e., color was cued), and alpha power from ventral regions increased when color was irrelevant. Thus, alpha-suppression mechanisms appear to operate during feature-based selection in much the same manner as has been shown for space-based attention. PMID:20237273

Integrating natural language processing and web GIS for interactive knowledge domain visualization

NASA Astrophysics Data System (ADS)

Du, Fangming

Recent years have seen a powerful shift towards data-rich environments throughout society. This has extended to a change in how the artifacts and products of scientific knowledge production can be analyzed and understood. Bottom-up approaches are on the rise that combine access to huge amounts of academic publications with advanced computer graphics and data processing tools, including natural language processing. Knowledge domain visualization is one of those multi-technology approaches, with its aim of turning domain-specific human knowledge into highly visual representations in order to better understand the structure and evolution of domain knowledge. For example, network visualizations built from co-author relations contained in academic publications can provide insight on how scholars collaborate with each other in one or multiple domains, and visualizations built from the text content of articles can help us understand the topical structure of knowledge domains. These knowledge domain visualizations need to support interactive viewing and exploration by users. Such spatialization efforts are increasingly looking to geography and GIS as a source of metaphors and practical technology solutions, even when non-georeferenced information is managed, analyzed, and visualized. When it comes to deploying spatialized representations online, web mapping and web GIS can provide practical technology solutions for interactive viewing of knowledge domain visualizations, from panning and zooming to the overlay of additional information. This thesis presents a novel combination of advanced natural language processing - in the form of topic modeling - with dimensionality reduction through self-organizing maps and the deployment of web mapping/GIS technology towards intuitive, GIS-like, exploration of a knowledge domain visualization. A complete workflow is proposed and implemented that processes any corpus of input text documents into a map form and leverages a web application framework to let users explore knowledge domain maps interactively. This workflow is implemented and demonstrated for a data set of more than 66,000 conference abstracts.

Visual cues to geographical orientation during low-level flight

NASA Technical Reports Server (NTRS)

Battiste, Vernol; Delzell, Suzanne

1991-01-01

A field study of an operational Emergency Medical Service (EMS) unit was conducted to investigate the relationships among geographical orientation, pilot decision making, and workload in EMS flights. The map data collected during this study were compared to protocols gathered in the laboratory, where pilots viewed a simulated flight over different types of unfamiliar terrain and verbally identified the features utilized to maintain geographical orientation. The EMS pilot's questionnaire data were compared with data from non-EMS helicopter pilots with comparable flight experience.

Large-Scale, High-Resolution Neurophysiological Maps Underlying fMRI of Macaque Temporal Lobe

PubMed Central

Papanastassiou, Alex M.; DiCarlo, James J.

2013-01-01

Maps obtained by functional magnetic resonance imaging (fMRI) are thought to reflect the underlying spatial layout of neural activity. However, previous studies have not been able to directly compare fMRI maps to high-resolution neurophysiological maps, particularly in higher level visual areas. Here, we used a novel stereo microfocal x-ray system to localize thousands of neural recordings across monkey inferior temporal cortex (IT), construct large-scale maps of neuronal object selectivity at subvoxel resolution, and compare those neurophysiology maps with fMRI maps from the same subjects. While neurophysiology maps contained reliable structure at the sub-millimeter scale, fMRI maps of object selectivity contained information at larger scales (>2.5 mm) and were only partly correlated with raw neurophysiology maps collected in the same subjects. However, spatial smoothing of neurophysiology maps more than doubled that correlation, while a variety of alternative transforms led to no significant improvement. Furthermore, raw spiking signals, once spatially smoothed, were as predictive of fMRI maps as local field potential signals. Thus, fMRI of the inferior temporal lobe reflects a spatially low-passed version of neurophysiology signals. These findings strongly validate the widespread use of fMRI for detecting large (>2.5 mm) neuronal domains of object selectivity but show that a complete understanding of even the most pure domains (e.g., faces vs nonface objects) requires investigation at fine scales that can currently only be obtained with invasive neurophysiological methods. PMID:24048850

Electric field imaging of single atoms

PubMed Central

Shibata, Naoya; Seki, Takehito; Sánchez-Santolino, Gabriel; Findlay, Scott D.; Kohno, Yuji; Matsumoto, Takao; Ishikawa, Ryo; Ikuhara, Yuichi

2017-01-01

In scanning transmission electron microscopy (STEM), single atoms can be imaged by detecting electrons scattered through high angles using post-specimen, annular-type detectors. Recently, it has been shown that the atomic-scale electric field of both the positive atomic nuclei and the surrounding negative electrons within crystalline materials can be probed by atomic-resolution differential phase contrast STEM. Here we demonstrate the real-space imaging of the (projected) atomic electric field distribution inside single Au atoms, using sub-Å spatial resolution STEM combined with a high-speed segmented detector. We directly visualize that the electric field distribution (blurred by the sub-Å size electron probe) drastically changes within the single Au atom in a shape that relates to the spatial variation of total charge density within the atom. Atomic-resolution electric field mapping with single-atom sensitivity enables us to examine their detailed internal and boundary structures. PMID:28555629

Intuitive Visualization of Transient Flow: Towards a Full 3D Tool

NASA Astrophysics Data System (ADS)

Michel, Isabel; Schröder, Simon; Seidel, Torsten; König, Christoph

2015-04-01

Visualization of geoscientific data is a challenging task especially when targeting a non-professional audience. In particular, the graphical presentation of transient vector data can be a significant problem. With STRING Fraunhofer ITWM (Kaiserslautern, Germany) in collaboration with delta h Ingenieurgesellschaft mbH (Witten, Germany) developed a commercial software for intuitive 2D visualization of 3D flow problems. Through the intuitive character of the visualization experts can more easily transport their findings to non-professional audiences. In STRING pathlets moving with the flow provide an intuition of velocity and direction of both steady-state and transient flow fields. The visualization concept is based on the Lagrangian view of the flow which means that the pathlets' movement is along the direction given by pathlines. In order to capture every detail of the flow an advanced method for intelligent, time-dependent seeding of the pathlets is implemented based on ideas of the Finite Pointset Method (FPM) originally conceived at and continuously developed by Fraunhofer ITWM. Furthermore, by the same method pathlets are removed during the visualization to avoid visual cluttering. Additional scalar flow attributes, for example concentration or potential, can either be mapped directly to the pathlets or displayed in the background of the pathlets on the 2D visualization plane. The extensive capabilities of STRING are demonstrated with the help of different applications in groundwater modeling. We will discuss the strengths and current restrictions of STRING which have surfaced during daily use of the software, for example by delta h. Although the software focusses on the graphical presentation of flow data for non-professional audiences its intuitive visualization has also proven useful to experts when investigating details of flow fields. Due to the popular reception of STRING and its limitation to 2D, the need arises for the extension to a full 3D tool. Currently STRING can generate animations of single 2D cuts, either planar or curved surfaces, through 3D simulation domains. To provide a general tool for experts enabling also direct exploration and analysis of large 3D flow fields the software needs to be extended to intuitive as well as interactive visualizations of entire 3D flow domains. The current research concerning this project, which is funded by the Federal Ministry for Economic Affairs and Energy (Germany), is presented.

Fusion of pixel and object-based features for weed mapping using unmanned aerial vehicle imagery

NASA Astrophysics Data System (ADS)

Gao, Junfeng; Liao, Wenzhi; Nuyttens, David; Lootens, Peter; Vangeyte, Jürgen; Pižurica, Aleksandra; He, Yong; Pieters, Jan G.

2018-05-01

The developments in the use of unmanned aerial vehicles (UAVs) and advanced imaging sensors provide new opportunities for ultra-high resolution (e.g., less than a 10 cm ground sampling distance (GSD)) crop field monitoring and mapping in precision agriculture applications. In this study, we developed a strategy for inter- and intra-row weed detection in early season maize fields from aerial visual imagery. More specifically, the Hough transform algorithm (HT) was applied to the orthomosaicked images for inter-row weed detection. A semi-automatic Object-Based Image Analysis (OBIA) procedure was developed with Random Forests (RF) combined with feature selection techniques to classify soil, weeds and maize. Furthermore, the two binary weed masks generated from HT and OBIA were fused for accurate binary weed image. The developed RF classifier was evaluated by 5-fold cross validation, and it obtained an overall accuracy of 0.945, and Kappa value of 0.912. Finally, the relationship of detected weeds and their ground truth densities was quantified by a fitted linear model with a coefficient of determination of 0.895 and a root mean square error of 0.026. Besides, the importance of input features was evaluated, and it was found that the ratio of vegetation length and width was the most significant feature for the classification model. Overall, our approach can yield a satisfactory weed map, and we expect that the obtained accurate and timely weed map from UAV imagery will be applicable to realize site-specific weed management (SSWM) in early season crop fields for reducing spraying non-selective herbicides and costs.

Identifying non-toxic doses of manganese for manganese-enhanced magnetic resonance imaging to map brain areas activated by operant behavior in trained rats.

PubMed

Gálosi, Rita; Szalay, Csaba; Aradi, Mihály; Perlaki, Gábor; Pál, József; Steier, Roy; Lénárd, László; Karádi, Zoltán

2017-04-01

Manganese-enhanced magnetic resonance imaging (MEMRI) offers unique advantages such as studying brain activation in freely moving rats, but its usefulness has not been previously evaluated during operant behavior training. Manganese in a form of MnCl 2 , at a dose of 20mg/kg, was intraperitoneally infused. The administration was repeated and separated by 24h to reach the dose of 40mg/kg or 60mg/kg, respectively. Hepatotoxicity of the MnCl 2 was evaluated by determining serum aspartate aminotransferase, alanine aminotransferase, total bilirubin, albumin and protein levels. Neurological examination was also carried out. The animals were tested in visual cue discriminated operant task. Imaging was performed using a 3T clinical MR scanner. T1 values were determined before and after MnCl 2 administrations. Manganese-enhanced images of each animal were subtracted from their baseline images to calculate decrease in the T1 value (ΔT1) voxel by voxel. The subtracted T1 maps of trained animals performing visual cue discriminated operant task, and those of naive rats were compared. The dose of 60mg/kg MnCl 2 showed hepatotoxic effect, but even these animals did not exhibit neurological symptoms. The dose of 20 and 40mg/kg MnCl 2 increased the number of omissions and did not affect the accuracy of performing the visual cue discriminated operant task. Using the accumulated dose of 40mg/kg, voxels with a significant enhanced ΔT1 value were detected in the following brain areas of the visual cue discriminated operant behavior performed animals compared to those in the controls: the visual, somatosensory, motor and premotor cortices, the insula, cingulate, ectorhinal, entorhinal, perirhinal and piriform cortices, hippocampus, amygdala with amygdalohippocampal areas, dorsal striatum, nucleus accumbens core, substantia nigra, and retrorubral field. In conclusion, the MEMRI proved to be a reliable method to accomplish brain activity mapping in correlation with the operant behavior of freely moving rodents. Copyright © 2016 Elsevier Inc. All rights reserved.

RIMS: An Integrated Mapping and Analysis System with Applications to Earth Sciences and Hydrology

NASA Astrophysics Data System (ADS)

Proussevitch, A. A.; Glidden, S.; Shiklomanov, A. I.; Lammers, R. B.

2011-12-01

A web-based information and computational system for analysis of spatially distributed Earth system, climate, and hydrologic data have been developed. The System allows visualization, data exploration, querying, manipulation and arbitrary calculations with any loaded gridded or vector polygon dataset. The system's acronym, RIMS, stands for its core functionality as a Rapid Integrated Mapping System. The system can be deployed for a Global scale projects as well as for regional hydrology and climatology studies. In particular, the Water Systems Analysis Group of the University of New Hampshire developed the global and regional (Northern Eurasia, pan-Arctic) versions of the system with different map projections and specific data. The system has demonstrated its potential for applications in other fields of Earth sciences and education. The key Web server/client components of the framework include (a) a visualization engine built on Open Source libraries (GDAL, PROJ.4, etc.) that are utilized in a MapServer; (b) multi-level data querying tools built on XML server-client communication protocols that allow downloading map data on-the-fly to a client web browser; and (c) data manipulation and grid cell level calculation tools that mimic desktop GIS software functionality via a web interface. Server side data management of the system is designed around a simple database of dataset metadata facilitating mounting of new data to the system and maintaining existing data in an easy manner. RIMS contains "built-in" river network data that allows for query of upstream areas on-demand which can be used for spatial data aggregation and analysis of sub-basin areas. RIMS is an ongoing effort and currently being used to serve a number of websites hosting a suite of hydrologic, environmental and other GIS data.

Estimation of Visual Maps with a Robot Network Equipped with Vision Sensors

PubMed Central

Gil, Arturo; Reinoso, Óscar; Ballesta, Mónica; Juliá, Miguel; Payá, Luis

2010-01-01

In this paper we present an approach to the Simultaneous Localization and Mapping (SLAM) problem using a team of autonomous vehicles equipped with vision sensors. The SLAM problem considers the case in which a mobile robot is equipped with a particular sensor, moves along the environment, obtains measurements with its sensors and uses them to construct a model of the space where it evolves. In this paper we focus on the case where several robots, each equipped with its own sensor, are distributed in a network and view the space from different vantage points. In particular, each robot is equipped with a stereo camera that allow the robots to extract visual landmarks and obtain relative measurements to them. We propose an algorithm that uses the measurements obtained by the robots to build a single accurate map of the environment. The map is represented by the three-dimensional position of the visual landmarks. In addition, we consider that each landmark is accompanied by a visual descriptor that encodes its visual appearance. The solution is based on a Rao-Blackwellized particle filter that estimates the paths of the robots and the position of the visual landmarks. The validity of our proposal is demonstrated by means of experiments with a team of real robots in a office-like indoor environment. PMID:22399930

Estimation of visual maps with a robot network equipped with vision sensors.

PubMed

Gil, Arturo; Reinoso, Óscar; Ballesta, Mónica; Juliá, Miguel; Payá, Luis

2010-01-01

In this paper we present an approach to the Simultaneous Localization and Mapping (SLAM) problem using a team of autonomous vehicles equipped with vision sensors. The SLAM problem considers the case in which a mobile robot is equipped with a particular sensor, moves along the environment, obtains measurements with its sensors and uses them to construct a model of the space where it evolves. In this paper we focus on the case where several robots, each equipped with its own sensor, are distributed in a network and view the space from different vantage points. In particular, each robot is equipped with a stereo camera that allow the robots to extract visual landmarks and obtain relative measurements to them. We propose an algorithm that uses the measurements obtained by the robots to build a single accurate map of the environment. The map is represented by the three-dimensional position of the visual landmarks. In addition, we consider that each landmark is accompanied by a visual descriptor that encodes its visual appearance. The solution is based on a Rao-Blackwellized particle filter that estimates the paths of the robots and the position of the visual landmarks. The validity of our proposal is demonstrated by means of experiments with a team of real robots in a office-like indoor environment.

An Intracranial Electroencephalography (iEEG) Brain Function Mapping Tool with an Application to Epilepsy Surgery Evaluation.

PubMed

Wang, Yinghua; Yan, Jiaqing; Wen, Jianbin; Yu, Tao; Li, Xiaoli

2016-01-01

Before epilepsy surgeries, intracranial electroencephalography (iEEG) is often employed in function mapping and epileptogenic foci localization. Although the implanted electrodes provide crucial information for epileptogenic zone resection, a convenient clinical tool for electrode position registration and Brain Function Mapping (BFM) visualization is still lacking. In this study, we developed a BFM Tool, which facilitates electrode position registration and BFM visualization, with an application to epilepsy surgeries. The BFM Tool mainly utilizes electrode location registration and function mapping based on pre-defined brain models from other software. In addition, the electrode node and mapping properties, such as the node size/color, edge color/thickness, mapping method, can be adjusted easily using the setting panel. Moreover, users may manually import/export location and connectivity data to generate figures for further application. The role of this software is demonstrated by a clinical study of language area localization. The BFM Tool helps clinical doctors and researchers visualize implanted electrodes and brain functions in an easy, quick and flexible manner. Our tool provides convenient electrode registration, easy brain function visualization, and has good performance. It is clinical-oriented and is easy to deploy and use. The BFM tool is suitable for epilepsy and other clinical iEEG applications.

An Intracranial Electroencephalography (iEEG) Brain Function Mapping Tool with an Application to Epilepsy Surgery Evaluation

PubMed Central

Wang, Yinghua; Yan, Jiaqing; Wen, Jianbin; Yu, Tao; Li, Xiaoli

2016-01-01

Objects: Before epilepsy surgeries, intracranial electroencephalography (iEEG) is often employed in function mapping and epileptogenic foci localization. Although the implanted electrodes provide crucial information for epileptogenic zone resection, a convenient clinical tool for electrode position registration and Brain Function Mapping (BFM) visualization is still lacking. In this study, we developed a BFM Tool, which facilitates electrode position registration and BFM visualization, with an application to epilepsy surgeries. Methods: The BFM Tool mainly utilizes electrode location registration and function mapping based on pre-defined brain models from other software. In addition, the electrode node and mapping properties, such as the node size/color, edge color/thickness, mapping method, can be adjusted easily using the setting panel. Moreover, users may manually import/export location and connectivity data to generate figures for further application. The role of this software is demonstrated by a clinical study of language area localization. Results: The BFM Tool helps clinical doctors and researchers visualize implanted electrodes and brain functions in an easy, quick and flexible manner. Conclusions: Our tool provides convenient electrode registration, easy brain function visualization, and has good performance. It is clinical-oriented and is easy to deploy and use. The BFM tool is suitable for epilepsy and other clinical iEEG applications. PMID:27199729

Direct visuomotor mapping for fast visually-evoked arm movements.

PubMed

Reynolds, Raymond F; Day, Brian L

2012-12-01

In contrast to conventional reaction time (RT) tasks, saccadic RT's to visual targets are very fast and unaffected by the number of possible targets. This can be explained by the sub-cortical circuitry underlying eye movements, which involves direct mapping between retinal input and motor output in the superior colliculus. Here we asked if the choice-invariance established for the eyes also applies to a special class of fast visuomotor responses of the upper limb. Using a target-pointing paradigm we observed very fast reaction times (<150 ms) which were completely unaffected as the number of possible target choices was increased from 1 to 4. When we introduced a condition of altered stimulus-response mapping, RT went up and a cost of choice was observed. These results can be explained by direct mapping between visual input and motor output, compatible with a sub-cortical pathway for visual control of the upper limb. Copyright © 2012 Elsevier Ltd. All rights reserved.

Remote sensing applied to land-use studies in Wyoming

NASA Technical Reports Server (NTRS)

Breckenridge, R. M.; Marrs, R. W.; Murphy, D. J.

1973-01-01

Impending development of Wyoming's vast fuel resources requires a quick and efficient method of land use inventory and evaluation. Preliminary evaluations of ERTS-1 imagery have shown that physiographic and land use inventory maps can be compiled by using a combination of visual and automated interpretation techniques. Test studies in the Powder River Basin showed that ERTS image interpretations can provide much of the needed physiographic and land use information. Water impoundments as small as one acre were detected and water bodies larger than five acres could be mapped and their acreage estimated. Flood plains and irrigated lands were successfully mapped, and some individual crops were identified and mapped. Coniferous and deciduous trees were mapped separately using color additive analysis on the ERTS multispectral imagery. Gross soil distinctions were made with the ERTS imagery, and were found to be closely related to the bedrock geology. Several broad unstable areas were identified. These were related to specific geologic and slope conditions and generally extended through large regions. Some new oil fields and all large open-cut coal mines were mapped. The most difficult task accomplished was that of mapping urban areas. Work in the urban areas provides a striking example of snow enhancement and the detail available from a snow enhanced image.

Self-Organizing Hidden Markov Model Map (SOHMMM): Biological Sequence Clustering and Cluster Visualization.

PubMed

Ferles, Christos; Beaufort, William-Scott; Ferle, Vanessa

2017-01-01

The present study devises mapping methodologies and projection techniques that visualize and demonstrate biological sequence data clustering results. The Sequence Data Density Display (SDDD) and Sequence Likelihood Projection (SLP) visualizations represent the input symbolical sequences in a lower-dimensional space in such a way that the clusters and relations of data elements are depicted graphically. Both operate in combination/synergy with the Self-Organizing Hidden Markov Model Map (SOHMMM). The resulting unified framework is in position to analyze automatically and directly raw sequence data. This analysis is carried out with little, or even complete absence of, prior information/domain knowledge.

Lessons in modern digital field geology: Open source software, 3D techniques, and the new world of digital mapping

NASA Astrophysics Data System (ADS)

Pavlis, Terry; Hurtado, Jose; Langford, Richard; Serpa, Laura

2014-05-01

Although many geologists refuse to admit it, it is time to put paper-based geologic mapping into the historical archives and move to the full potential of digital mapping techniques. For our group, flat map digital geologic mapping is now a routine operation in both research and instruction. Several software options are available, and basic proficiency with the software can be learned in a few hours of instruction and practice. The first practical field GIS software, ArcPad, remains a viable, stable option on Windows-based systems. However, the vendor seems to be moving away from ArcPad in favor of mobile software solutions that are difficult to implement without GIS specialists. Thus, we have pursued a second software option based on the open source program QGIS. Our QGIS system uses the same shapefile-centric data structure as our ArcPad system, including similar pop-up data entry forms and generic graphics for easy data management in the field. The advantage of QGIS is that the same software runs on virtually all common platforms except iOS, although the Android version remains unstable as of this writing. A third software option we are experimenting with for flat map-based field work is Fieldmove, a derivative of the 3D-capable program Move developed by Midland Valley. Our initial experiments with Fieldmove are positive, particularly with the new, inexpensive (<300Euros) Windows tablets. However, the lack of flexibility in data structure makes for cumbersome workflows when trying to interface our existing shapefile-centric data structures to Move. Nonetheless, in spring 2014 we will experiment with full-3D immersion in the field using the full Move software package in combination with ground based LiDAR and photogrammetry. One new workflow suggested by our initial experiments is that field geologists should consider using photogrammetry software to capture 3D visualizations of key outcrops. This process is now straightforward in several software packages, and it affords a previously unheard of potential for communicating the complexity of key exposures. For example, in studies of metamorphic structures we often search for days to find "Rosetta Stone" outcrops that display key geometric relationships. While conventional photographs rarely can capture the essence of the field exposure, capturing a true 3D representation of the exposure with multiple photos from many orientations can solve this communication problem. As spatial databases evolve these 3D models should be readily importable into the database.

Tile-based parallel coordinates and its application in financial visualization

NASA Astrophysics Data System (ADS)

Alsakran, Jamal; Zhao, Ye; Zhao, Xinlei

2010-01-01

Parallel coordinates technique has been widely used in information visualization applications and it has achieved great success in visualizing multivariate data and perceiving their trends. Nevertheless, visual clutter usually weakens or even diminishes its ability when the data size increases. In this paper, we first propose a tile-based parallel coordinates, where the plotting area is divided into rectangular tiles. Each tile stores an intersection density that counts the total number of polylines intersecting with that tile. Consequently, the intersection density is mapped to optical attributes, such as color and opacity, by interactive transfer functions. The method visualizes the polylines efficiently and informatively in accordance with the density distribution, and thus, reduces visual cluttering and promotes knowledge discovery. The interactivity of our method allows the user to instantaneously manipulate the tiles distribution and the transfer functions. Specifically, the classic parallel coordinates rendering is a special case of our method when each tile represents only one pixel. A case study on a real world data set, U.S. stock mutual fund data of year 2006, is presented to show the capability of our method in visually analyzing financial data. The presented visual analysis is conducted by an expert in the domain of finance. Our method gains the support from professionals in the finance field, they embrace it as a potential investment analysis tool for mutual fund managers, financial planners, and investors.

MyGeoHub: A Collaborative Geospatial Research and Education Platform

NASA Astrophysics Data System (ADS)

Kalyanam, R.; Zhao, L.; Biehl, L. L.; Song, C. X.; Merwade, V.; Villoria, N.

2017-12-01

Scientific research is increasingly collaborative and globally distributed; research groups now rely on web-based scientific tools and data management systems to simplify their day-to-day collaborative workflows. However, such tools often lack seamless interfaces, requiring researchers to contend with manual data transfers, annotation and sharing. MyGeoHub is a web platform that supports out-of-the-box, seamless workflows involving data ingestion, metadata extraction, analysis, sharing and publication. MyGeoHub is built on the HUBzero cyberinfrastructure platform and adds general-purpose software building blocks (GABBs), for geospatial data management, visualization and analysis. A data management building block iData, processes geospatial files, extracting metadata for keyword and map-based search while enabling quick previews. iData is pervasive, allowing access through a web interface, scientific tools on MyGeoHub or even mobile field devices via a data service API. GABBs includes a Python map library as well as map widgets that in a few lines of code, generate complete geospatial visualization web interfaces for scientific tools. GABBs also includes powerful tools that can be used with no programming effort. The GeoBuilder tool provides an intuitive wizard for importing multi-variable, geo-located time series data (typical of sensor readings, GPS trackers) to build visualizations supporting data filtering and plotting. MyGeoHub has been used in tutorials at scientific conferences and educational activities for K-12 students. MyGeoHub is also constantly evolving; the recent addition of Jupyter and R Shiny notebook environments enable reproducible, richly interactive geospatial analyses and applications ranging from simple pre-processing to published tools. MyGeoHub is not a monolithic geospatial science gateway, instead it supports diverse needs ranging from just a feature-rich data management system, to complex scientific tools and workflows.

Virtual reality hardware for use in interactive 3D data fusion and visualization

NASA Astrophysics Data System (ADS)

Gourley, Christopher S.; Abidi, Mongi A.

1997-09-01

Virtual reality has become a tool for use in many areas of research. We have designed and built a VR system for use in range data fusion and visualization. One major VR tool is the CAVE. This is the ultimate visualization tool, but comes with a large price tag. Our design uses a unique CAVE whose graphics are powered by a desktop computer instead of a larger rack machine making it much less costly. The system consists of a screen eight feet tall by twenty-seven feet wide giving a variable field-of-view currently set at 160 degrees. A silicon graphics Indigo2 MaxImpact with the impact channel option is used for display. This gives the capability to drive three projectors at a resolution of 640 by 480 for use in displaying the virtual environment and one 640 by 480 display for a user control interface. This machine is also the first desktop package which has built-in hardware texture mapping. This feature allows us to quickly fuse the range and intensity data and other multi-sensory data. The final goal is a complete 3D texture mapped model of the environment. A dataglove, magnetic tracker, and spaceball are to be used for manipulation of the data and navigation through the virtual environment. This system gives several users the ability to interactively create 3D models from multiple range images.

Before the N400: effects of lexical-semantic violations in visual cortex.

PubMed

Dikker, Suzanne; Pylkkanen, Liina

2011-07-01

There exists an increasing body of research demonstrating that language processing is aided by context-based predictions. Recent findings suggest that the brain generates estimates about the likely physical appearance of upcoming words based on syntactic predictions: words that do not physically look like the expected syntactic category show increased amplitudes in the visual M100 component, the first salient MEG response to visual stimulation. This research asks whether violations of predictions based on lexical-semantic information might similarly generate early visual effects. In a picture-noun matching task, we found early visual effects for words that did not accurately describe the preceding pictures. These results demonstrate that, just like syntactic predictions, lexical-semantic predictions can affect early visual processing around ∼100ms, suggesting that the M100 response is not exclusively tuned to recognizing visual features relevant to syntactic category analysis. Rather, the brain might generate predictions about upcoming visual input whenever it can. However, visual effects of lexical-semantic violations only occurred when a single lexical item could be predicted. We argue that this may be due to the fact that in natural language processing, there is typically no straightforward mapping between lexical-semantic fields (e.g., flowers) and visual or auditory forms (e.g., tulip, rose, magnolia). For syntactic categories, in contrast, certain form features do reliably correlate with category membership. This difference may, in part, explain why certain syntactic effects typically occur much earlier than lexical-semantic effects. Copyright © 2011 Elsevier Inc. All rights reserved.

Scanning laser polarimetry using variable corneal compensation in the detection of glaucoma with localized visual field defects.

PubMed

Kook, Michael S; Cho, Hyun-soo; Seong, Mincheol; Choi, Jaewan

2005-11-01

To evaluate the ability of scanning laser polarimetry parameters and a novel deviation map algorithm to discriminate between healthy and early glaucomatous eyes with localized visual field (VF) defects confined to one hemifield. Prospective case-control study. Seventy glaucomatous eyes with localized VF defects and 66 normal controls. A Humphrey field analyzer 24-2 full-threshold test and scanning laser polarimetry with variable corneal compensation were used. We assessed the sensitivity and specificity of scanning laser polarimetry parameters, sensitivity and cutoff values for scanning laser polarimetry deviation map algorithms at different specificity values (80%, 90%, and 95%) in the detection of glaucoma, and correlations between the algorithms of scanning laser polarimetry and of the pattern deviation derived from Humphrey field analyzer testing. There were significant differences between the glaucoma group and normal subjects in the mean parametric values of the temporal, superior, nasal, inferior, temporal (TSNIT) average, superior average, inferior average, and TSNIT standard deviation (SD) (P<0.05). The sensitivity and specificity of each scanning laser polarimetry variable was as follows: TSNIT, 44.3% (95% confidence interval [CI], 39.8%-49.8%) and 100% (95.4%-100%); superior average, 30% (25.5%-34.5%) and 97% (93.5%-100%); inferior average, 45.7% (42.2%-49.2%) and 100% (95.8%-100%); and TSNIT SD, 30% (25.9%-34.1%) and 97% (93.2%-100%), respectively (when abnormal was defined as P<0.05). Based on nerve fiber indicator cutoff values of > or =30 and > or =51 to indicate glaucoma, sensitivities were 54.3% (50.1%-58.5%) and 10% (6.4%-13.6%), and specificities were 97% (93.2%-100%) and 100% (95.8%-100%), respectively. The range of areas under the receiver operating characteristic curves using the scanning laser polarimetry deviation map algorithm was 0.790 to 0.879. Overall sensitivities combining each probability scale and severity score at 80%, 90%, and 95% specificities were 90.0% (95% CI, 86.4%-93.6%), 71.4% (67.4%-75.4%), and 60.0% (56.2%-63.8%), respectively. There was a statistically significant correlation between the scanning laser polarimetry severity score and the VF severity score (R2 = 0.360, P<0.001). Scanning laser polarimetry parameters may not be sufficiently sensitive to detect glaucomatous patients with localized VF damage. Our algorithm using the scanning laser polarimetry deviation map may enhance the understanding of scanning laser polarimetry printouts in terms of the locality, deviation size, and severity of localized retinal nerve fiber layer defects in eyes with localized VF loss.

Will it Blend? Visualization and Accuracy Evaluation of High-Resolution Fuzzy Vegetation Maps

NASA Astrophysics Data System (ADS)

Zlinszky, A.; Kania, A.

2016-06-01

Instead of assigning every map pixel to a single class, fuzzy classification includes information on the class assigned to each pixel but also the certainty of this class and the alternative possible classes based on fuzzy set theory. The advantages of fuzzy classification for vegetation mapping are well recognized, but the accuracy and uncertainty of fuzzy maps cannot be directly quantified with indices developed for hard-boundary categorizations. The rich information in such a map is impossible to convey with a single map product or accuracy figure. Here we introduce a suite of evaluation indices and visualization products for fuzzy maps generated with ensemble classifiers. We also propose a way of evaluating classwise prediction certainty with "dominance profiles" visualizing the number of pixels in bins according to the probability of the dominant class, also showing the probability of all the other classes. Together, these data products allow a quantitative understanding of the rich information in a fuzzy raster map both for individual classes and in terms of variability in space, and also establish the connection between spatially explicit class certainty and traditional accuracy metrics. These map products are directly comparable to widely used hard boundary evaluation procedures, support active learning-based iterative classification and can be applied for operational use.

A novel visual saliency analysis model based on dynamic multiple feature combination strategy

NASA Astrophysics Data System (ADS)

Lv, Jing; Ye, Qi; Lv, Wen; Zhang, Libao

2017-06-01

The human visual system can quickly focus on a small number of salient objects. This process was known as visual saliency analysis and these salient objects are called focus of attention (FOA). The visual saliency analysis mechanism can be used to extract the salient regions and analyze saliency of object in an image, which is time-saving and can avoid unnecessary costs of computing resources. In this paper, a novel visual saliency analysis model based on dynamic multiple feature combination strategy is introduced. In the proposed model, we first generate multi-scale feature maps of intensity, color and orientation features using Gaussian pyramids and the center-surround difference. Then, we evaluate the contribution of all feature maps to the saliency map according to the area of salient regions and their average intensity, and attach different weights to different features according to their importance. Finally, we choose the largest salient region generated by the region growing method to perform the evaluation. Experimental results show that the proposed model cannot only achieve higher accuracy in saliency map computation compared with other traditional saliency analysis models, but also extract salient regions with arbitrary shapes, which is of great value for the image analysis and understanding.

Criteria for the optimal selection of remote sensing optical images to map event landslides

NASA Astrophysics Data System (ADS)

Fiorucci, Federica; Giordan, Daniele; Santangelo, Michele; Dutto, Furio; Rossi, Mauro; Guzzetti, Fausto

2018-01-01

Landslides leave discernible signs on the land surface, most of which can be captured in remote sensing images. Trained geomorphologists analyse remote sensing images and map landslides through heuristic interpretation of photographic and morphological characteristics. Despite a wide use of remote sensing images for landslide mapping, no attempt to evaluate how the image characteristics influence landslide identification and mapping exists. This paper presents an experiment to determine the effects of optical image characteristics, such as spatial resolution, spectral content and image type (monoscopic or stereoscopic), on landslide mapping. We considered eight maps of the same landslide in central Italy: (i) six maps obtained through expert heuristic visual interpretation of remote sensing images, (ii) one map through a reconnaissance field survey, and (iii) one map obtained through a real-time kinematic (RTK) differential global positioning system (dGPS) survey, which served as a benchmark. The eight maps were compared pairwise and to a benchmark. The mismatch between each map pair was quantified by the error index, E. Results show that the map closest to the benchmark delineation of the landslide was obtained using the higher resolution image, where the landslide signature was primarily photographical (in the landslide source and transport area). Conversely, where the landslide signature was mainly morphological (in the landslide deposit) the best mapping result was obtained using the stereoscopic images. Albeit conducted on a single landslide, the experiment results are general, and provide useful information to decide on the optimal imagery for the production of event, seasonal and multi-temporal landslide inventory maps.

Glocalized New Age Spirituality: A Mental Map of the New Central Bus Station in Tel Aviv, Deciphered through Its Visual Codes and Based on Ethno-Visual Research

ERIC Educational Resources Information Center

Ben-Peshat, Malka; Sitton, Shoshana

2011-01-01

We present here the findings of an ethno-visual research study involving the creation of a mental map of images, artifacts and practices in Tel Aviv's New Central Bus Station. This huge and complex building, part bus station, part shopping mall, has become a stage for multicultural encounters and interactions among diverse communities of users.…

A test of a linear model of glaucomatous structure-function loss reveals sources of variability in retinal nerve fiber and visual field measurements.

PubMed

Hood, Donald C; Anderson, Susan C; Wall, Michael; Raza, Ali S; Kardon, Randy H

2009-09-01

Retinal nerve fiber (RNFL) thickness and visual field loss data from patients with glaucoma were analyzed in the context of a model, to better understand individual variation in structure versus function. Optical coherence tomography (OCT) RNFL thickness and standard automated perimetry (SAP) visual field loss were measured in the arcuate regions of one eye of 140 patients with glaucoma and 82 normal control subjects. An estimate of within-individual (measurement) error was obtained by repeat measures made on different days within a short period in 34 patients and 22 control subjects. A linear model, previously shown to describe the general characteristics of the structure-function data, was extended to predict the variability in the data. For normal control subjects, between-individual error (individual differences) accounted for 87% and 71% of the total variance in OCT and SAP measures, respectively. SAP within-individual error increased and then decreased with increased SAP loss, whereas OCT error remained constant. The linear model with variability (LMV) described much of the variability in the data. However, 12.5% of the patients' points fell outside the 95% boundary. An examination of these points revealed factors that can contribute to the overall variability in the data. These factors include epiretinal membranes, edema, individual variation in field-to-disc mapping, and the location of blood vessels and degree to which they are included by the RNFL algorithm. The model and the partitioning of within- versus between-individual variability helped elucidate the factors contributing to the considerable variability in the structure-versus-function data.

Discussing State-of-the-Art Spatial Visualization Techniques Applicable for the Epidemiological Surveillance Data on the Example of Campylobacter spp. in Raw Chicken Meat.

PubMed

Plaza-Rodríguez, C; Appel, B; Kaesbohrer, A; Filter, M

2016-08-01

Within the European activities for the 'Monitoring and Collection of Information on Zoonoses', annually EFSA publishes a European report, including information related to the prevalence of Campylobacter spp. in Germany. Spatial epidemiology becomes here a fundamental tool for the generation of these reports, including the representation of prevalence as an essential element. Until now, choropleth maps are the default visualization technique applied in epidemiological monitoring and surveillance reports made by EFSA and German authorities. However, due to its limitations, it seems to be reasonable to explore alternative chart type. Four maps including choropleth, cartogram, graduated symbols and dot-density maps were created to visualize real-world sample data on the prevalence of Campylobacter spp. in raw chicken meat samples in Germany in 2011. In addition, adjacent and coincident maps were created to visualize also the associated uncertainty. As an outcome, we found that there is not a single data visualization technique that encompasses all the necessary features to visualize prevalence data alone or prevalence data together with their associated uncertainty. All the visualization techniques contemplated in this study demonstrated to have both advantages and disadvantages. To determine which visualization technique should be used for future reports, we recommend to create a dialogue between end-users and epidemiologists on the basis of sample data and charts. The final decision should also consider the knowledge and experience of end-users as well as the specific objective to be achieved with the charts. © 2015 The Authors. Zoonoses and Public Health Published by Blackwell Verlag GmbH.

Population Coding of Visual Space: Comparison of Spatial Representations in Dorsal and Ventral Pathways

PubMed Central

Sereno, Anne B.; Lehky, Sidney R.

2011-01-01

Although the representation of space is as fundamental to visual processing as the representation of shape, it has received relatively little attention from neurophysiological investigations. In this study we characterize representations of space within visual cortex, and examine how they differ in a first direct comparison between dorsal and ventral subdivisions of the visual pathways. Neural activities were recorded in anterior inferotemporal cortex (AIT) and lateral intraparietal cortex (LIP) of awake behaving monkeys, structures associated with the ventral and dorsal visual pathways respectively, as a stimulus was presented at different locations within the visual field. In spatially selective cells, we find greater modulation of cell responses in LIP with changes in stimulus position. Further, using a novel population-based statistical approach (namely, multidimensional scaling), we recover the spatial map implicit within activities of neural populations, allowing us to quantitatively compare the geometry of neural space with physical space. We show that a population of spatially selective LIP neurons, despite having large receptive fields, is able to almost perfectly reconstruct stimulus locations within a low-dimensional representation. In contrast, a population of AIT neurons, despite each cell being spatially selective, provide less accurate low-dimensional reconstructions of stimulus locations. They produce instead only a topologically (categorically) correct rendition of space, which nevertheless might be critical for object and scene recognition. Furthermore, we found that the spatial representation recovered from population activity shows greater translation invariance in LIP than in AIT. We suggest that LIP spatial representations may be dimensionally isomorphic with 3D physical space, while in AIT spatial representations may reflect a more categorical representation of space (e.g., “next to” or “above”). PMID:21344010

Functional MRI mapping of visual function and selective attention for performance assessment and presurgical planning using conjunctive visual search

PubMed Central

Parker, Jason G; Zalusky, Eric J; Kirbas, Cemil

2014-01-01

Background Accurate mapping of visual function and selective attention using fMRI is important in the study of human performance as well as in presurgical treatment planning of lesions in or near visual centers of the brain. Conjunctive visual search (CVS) is a useful tool for mapping visual function during fMRI because of its greater activation extent compared with high-capacity parallel search processes. Aims The purpose of this work was to develop and evaluate a CVS that was capable of generating consistent activation in the basic and higher level visual areas of the brain by using a high number of distractors as well as an optimized contrast condition. Materials and methods Images from 10 healthy volunteers were analyzed and brain regions of greatest activation and deactivation were determined using a nonbiased decomposition of the results at the hemisphere, lobe, and gyrus levels. The results were quantified in terms of activation and deactivation extent and mean z-statistic. Results The proposed CVS was found to generate robust activation of the occipital lobe, as well as regions in the middle frontal gyrus associated with coordinating eye movements and in regions of the insula associated with task-level control and focal attention. As expected, the task demonstrated deactivation patterns commonly implicated in the default-mode network. Further deactivation was noted in the posterior region of the cerebellum, most likely associated with the formation of optimal search strategy. Conclusion We believe the task will be useful in studies of visual and selective attention in the neuroscience community as well as in mapping visual function in clinical fMRI. PMID:24683515

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Like; Kang, Jian, E-mail: j.kang@sheffield.ac.uk; Schroth, Olaf

Large scale transportation projects can adversely affect the visual perception of environmental quality and require adequate visual impact assessment. In this study, we investigated the effects of the characteristics of the road project and the character of the existing landscape on the perceived visual impact of motorways, and developed a GIS-based prediction model based on the findings. An online survey using computer-visualised scenes of different motorway and landscape scenarios was carried out to obtain perception-based judgements on the visual impact. Motorway scenarios simulated included the baseline scenario without road, original motorway, motorways with timber noise barriers, transparent noise barriers andmore » tree screen; different landscape scenarios were created by changing land cover of buildings and trees in three distance zones. The landscape content of each scene was measured in GIS. The result shows that presence of a motorway especially with the timber barrier significantly decreases the visual quality of the view. The resulted visual impact tends to be lower where it is less visually pleasant with more buildings in the view, and can be slightly reduced by the visual absorption effect of the scattered trees between the motorway and the viewpoint. Based on the survey result, eleven predictors were identified for the visual impact prediction model which was applied in GIS to generate maps of visual impact of motorways in different scenarios. The proposed prediction model can be used to achieve efficient and reliable assessment of visual impact of motorways. - Highlights: • Motorways induce significant visual impact especially with timber noise barriers. • Visual impact is negatively correlated with amount of buildings in the view. • Visual impact is positively correlated with percentage of trees in the view. • Perception-based motorway visual impact prediction model using mapped predictors • Predicted visual impacts in different scenarios are mapped in GIS.« less

Drawing Road Networks with Mental Maps.

PubMed

Lin, Shih-Syun; Lin, Chao-Hung; Hu, Yan-Jhang; Lee, Tong-Yee

2014-09-01

Tourist and destination maps are thematic maps designed to represent specific themes in maps. The road network topologies in these maps are generally more important than the geometric accuracy of roads. A road network warping method is proposed to facilitate map generation and improve theme representation in maps. The basic idea is deforming a road network to meet a user-specified mental map while an optimization process is performed to propagate distortions originating from road network warping. To generate a map, the proposed method includes algorithms for estimating road significance and for deforming a road network according to various geometric and aesthetic constraints. The proposed method can produce an iconic mark of a theme from a road network and meet a user-specified mental map. Therefore, the resulting map can serve as a tourist or destination map that not only provides visual aids for route planning and navigation tasks, but also visually emphasizes the presentation of a theme in a map for the purpose of advertising. In the experiments, the demonstrations of map generations show that our method enables map generation systems to generate deformed tourist and destination maps efficiently.

Map It Then Write It

ERIC Educational Resources Information Center

Lott, Kimberly; Read, Sylvia

2015-01-01

All writing begins with ideas, but young students often need visual cues to help them organize their thoughts before beginning to write. For this reason, many elementary teachers use graphic organizers or thinking maps to help students visualize patterns and organize their ideas within the different genres of writing. Graphic organizers such as…

Map-Reading Skill Development with 3D Technologies

ERIC Educational Resources Information Center

Carbonell Carrera, Carlos; Avarvarei, Bogdan Vlad; Chelariu, Elena Liliana; Draghia, Lucia; Avarvarei, Simona Catrinel

2017-01-01

Landforms often are represented on maps using abstract cartographic techniques that the reader must interpret for successful three-dimensional terrain visualization. New technologies in 3D landscape representation, both digital and tangible, offer the opportunity to visualize terrain in new ways. The results of a university student workshop, in…

A New Perspective on Surface Weather Maps

ERIC Educational Resources Information Center

Meyer, Steve

2006-01-01

A two-dimensional weather map is actually a physical representation of three-dimensional atmospheric conditions at a specific point in time. Abstract thinking is required to visualize this two-dimensional image in three-dimensional form. But once that visualization is accomplished, many of the meteorological concepts and processes conveyed by the…

Concept Maps as Cognitive Visualizations of Writing Assignments

ERIC Educational Resources Information Center

Villalon, Jorge; Calvo, Rafael A.

2011-01-01

Writing assignments are ubiquitous in higher education. Writing develops not only communication skills, but also higher-level cognitive processes that facilitate deep learning. Cognitive visualizations, such as concept maps, can also be used as part of learning activities including as a form of scaffolding, or to trigger reflection by making…