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Sample records for activity images figure

  1. Atypical Activation during the Embedded Figures Task as a Functional Magnetic Resonance Imaging Endophenotype of Autism

    ERIC Educational Resources Information Center

    Spencer, Michael D.; Holt, Rosemary J.; Chura, Lindsay R.; Calder, Andrew J.; Suckling, John; Bullmore, Edward T.; Baron-Cohen, Simon

    2012-01-01

    Atypical activation during the Embedded Figures Task has been demonstrated in autism, but has not been investigated in siblings or related to measures of clinical severity. We identified atypical activation during the Embedded Figures Task in participants with autism and unaffected siblings compared with control subjects in a number of temporal…

  2. Generating Ambiguous Figure-Ground Images.

    PubMed

    Kuo, Ying-Miao; Chu, Hung-Kuo; Chi, Ming-Te; Lee, Ruen-Rone; Lee, Tong-Yee

    2016-02-26

    Ambiguous figure-ground images, mostly represented as binary images, are fascinating as they present viewers a visual phenomena of perceiving multiple interpretations from a single image. In one possible interpretation, the white region is seen as a foreground figure while the black region is treated as shapeless background. Such perception can reverse instantly at any moment. In this paper, we investigate the theory behind this ambiguous perception and present an automatic algorithm to generate such images. We model the problem as a binary image composition using two object contours and approach it through a three-stage pipeline. The algorithm first performs a partial shape matching to find a good partial contour matching between objects. This matching is based on a content-aware shape matching metric, which captures features of ambiguous figure-ground images. Then we combine matched contours into a compound contour using an adaptive contour deformation, followed by computing an optimal cropping window and image binarization for the compound contour that maximize the completeness of object contours in the final composition. We have tested our system using a wide range of input objects and generated a large number of convincing examples with or without user guidance. The efficiency of our system and quality of results are verified through an extensive experimental study.

  3. Figure Caption for pair of images of 'Comet Nucleus Q

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Figure Caption for pair of images of 'Comet Nucleus Q'. 21Jul94 Last Look at the Q-nuclei First image - March 30, 1994. Two Q-nuclei and a split nucleus, P. Second image - July 20, 1994. at T - 10 hours. Both nuclei still show no sign of further fragmentation, although the coma near each is being stretched out along the direction of motion. Both images were taken with the WFPC2 Planetary Camera using a red filter. Credit: H. A. Weaver and T. E. Smith

  4. Superpixel Cut for Figure-Ground Image Segmentation

    NASA Astrophysics Data System (ADS)

    Yang, Michael Ying; Rosenhahn, Bodo

    2016-06-01

    Figure-ground image segmentation has been a challenging problem in computer vision. Apart from the difficulties in establishing an effective framework to divide the image pixels into meaningful groups, the notions of figure and ground often need to be properly defined by providing either user inputs or object models. In this paper, we propose a novel graph-based segmentation framework, called superpixel cut. The key idea is to formulate foreground segmentation as finding a subset of superpixels that partitions a graph over superpixels. The problem is formulated as Min-Cut. Therefore, we propose a novel cost function that simultaneously minimizes the inter-class similarity while maximizing the intra-class similarity. This cost function is optimized using parametric programming. After a small learning step, our approach is fully automatic and fully bottom-up, which requires no high-level knowledge such as shape priors and scene content. It recovers coherent components of images, providing a set of multiscale hypotheses for high-level reasoning. We evaluate our proposed framework by comparing it to other generic figure-ground segmentation approaches. Our method achieves improved performance on state-of-the-art benchmark databases.

  5. Exploiting transient phenomena for imaging with breath figures

    NASA Astrophysics Data System (ADS)

    Sasikumar, Harish; Varma, Manoj M.

    2017-02-01

    Breath figures refer to the patterns formed when vapor condenses into the liquid phase on a surface, revealing heterogeneities in topography or chemical composition. These figures are composed of micro-droplets, which scatter light and produce optical contrast. Differences in hydrophobicity imposed by surface features or contaminants result in a difference in micro-droplet densities, which has been used in applications such as substrate independent optical visualization of single layer graphene flakes. Here, we show that transient phenomena, such as the pinning transition of micro-droplets condensed over a polymer surface, can be used to enhance the optical contrast even when the time averaged difference in micro-droplet densities is not substantial. Thus, this work opens a new way of visualizing surface heterogeneities using transient phenomena occurring during condensation or evaporation of micro-droplets as opposed to only using time averaged differences in wettability due to the surface features.

  6. Nondestructive imaging of hidden figures on license plates by X-ray radiograph.

    PubMed

    Jeon, Oc-Yeub; Kim, Sang-Hyeon; Lee, Joong; Park, Jong-Taek; Kim, Tae-Hoon; Park, Hak-Soo; Huh, Il-Kwon; Kang, Hyung-Tae

    2009-07-01

    In this case, we investigated the modified license plates. The evidences had new embossing pressed serial numbers after erasing the original numbers on the license plates by hammering. The X-ray radiograph could visualize the hidden figures; those were virtually unseen by naked eyes or undetectable by ordinary photography. To reveal the erased figures, we performed image processing with computer software after X-ray radiographs. It proved to be an efficient nondestructive way to visualize the hidden original figures on metals.

  7. Classification of visual signs in abdominal CT image figures in biomedical literature

    NASA Astrophysics Data System (ADS)

    Xue, Zhiyun; You, Daekeun; Antani, Sameer; Long, L. Rodney; Demner-Fushman, Dina; Thoma, George R.

    2014-03-01

    "Imaging signs" are a critical part of radiology's language. They not only are important for conveying diagnosis, but may also aid in indexing radiology literature and retrieving relevant cases and images. Here we report our work towards representing and categorizing imaging signs of abdominal abnormalities in figures in the radiology literature. Given a region-of-interest (ROI) from a figure, our goal was to assign a correct imaging sign label to that ROI from the following seven: accordion, comb, ring, sandwich, small bowel feces, target, or whirl. As training and test data, we created our own "gold standard" dataset of regions containing imaging signs. We computed 2997 feature attributes to represent imaging sign characteristics for each ROI in training and test sets. Following feature selection they were reduced to 70 attributes and were input to a Support Vector Machine classifier. We applied image-enhancement methods to compensate for variable quality of the images in radiology articles. In particular we developed a method for automatic detection and removal of pointers/markers (arrows, arrowheads, and asterisk symbols) on the images. These pointers/markers are valuable for approximately locating ROIs; however, they degrade the classification because they are often (partially) included in the training ROIs. On a test set of 283 ROIs, our method achieved an overall accuracy of 70% in labeling the seven signs, which we believe is a promising result for using imaging signs to search/retrieve radiology literature. This work is also potentially valuable for the creation of a visual ontology of biomedical imaging entities.

  8. Figure-ground separation during active electrolocation in the weakly electric fish, Gnathonemus petersii.

    PubMed

    Fechler, Katharina; von der Emde, Gerhard

    2013-01-01

    The weakly electric fish Gnathonemus petersii uses active electrolocation to detect and discriminate between objects in its environment. Objects are recognised by analysing the electric images, which they project onto the fish's skin. In this study, we determined whether different types of large backgrounds interfere with the fishes' ability to discriminate between objects. Fish were trained in a food-rewarded two-alternative forced-choice procedure to discriminate between two objects. In subsequent tests, structured and non-structured as well as stationary and moving backgrounds were positioned behind the objects and discrimination performance between objects was measured at different object distances. To define the electrosensory stimuli during the tests, the electric images of the objects and backgrounds used were measured. Without a background G. petersii was able to discriminate between objects up to distances of about 3-4 cm. Even though the electric images of background and object superimposed in a complex way, the addition of stationary structured or plain backgrounds had only minor effects on the range of object discrimination. However, two types of moving backgrounds improved electrolocation by extending the range of object discrimination up to a distance of almost 5 cm. This suggests that movements in the environment plays an important role for object identification and improves figure-ground separation during active electrolocation.

  9. Determining the relative importance of figures in journal articles to find representative images

    NASA Astrophysics Data System (ADS)

    Müller, Henning; Foncubierta-Rodríguez, Antonio; Lin, Chang; Eggel, Ivan

    2013-03-01

    When physicians are searching for articles in the medical literature, images of the articles can help determining relevance of the article content for a specific information need. The visual image representation can be an advantage in effectiveness (quality of found articles) and also in efficiency (speed of determining relevance or irrelevance) as many articles can likely be excluded much quicker by looking at a few representative images. In domains such as medical information retrieval, allowing to determine relevance quickly and accurately is an important criterion. This becomes even more important when small interfaces are used as it is frequently the case on mobile phones and tablets to access scientific data whenever information needs arise. In scientific articles many figures are used and particularly in the biomedical literature only a subset may be relevant for determining the relevance of a specific article to an information need. In many cases clinical images can be seen as more important for visual appearance than graphs or histograms that require looking at the context for interpretation. To get a clearer idea of image relevance in articles, a user test with a physician was performed who classified images of biomedical research articles into categories of importance that can subsequently be used to evaluate algorithms that automatically select images as representative examples. The manual sorting of images of 50 journal articles of BioMedCentral with each containing more than 8 figures by importance also allows to derive several rules that determine how to choose images and how to develop algorithms for choosing the most representative images of specific texts. This article describes the user tests and can be a first important step to evaluate automatic tools to select representative images for representing articles and potentially also images in other contexts, for example when representing patient records or other medical concepts when selecting

  10. Decreased beta-band activity is correlated with disambiguation of hidden figures.

    PubMed

    Minami, Tetsuto; Noritake, Yosuke; Nakauchi, Shigeki

    2014-04-01

    Insight is commonly described as sudden comprehension, sometimes called an "Aha! moment." In everyday life, we apply the process of insight to problems that are difficult to solve at first glance or that we perceive as ambiguous; however the brain dynamics underlying the disambiguation process remains elusive. Beta-band oscillatory brain activity has been hypothesized to reflect the transition of cognitive states. To elucidate the neural mechanism of insight, we recorded electroencephalograms while subjects were presented with hidden figures followed by unambiguous, gray images. We identified oscillatory activity to detect temporal changes, and compared brain activity that occurred during a perceptual transition with activity that occurred when no perceptual transition occurred. Statistical comparison confirmed stronger beta-power decrease during perceptual transition. Source analysis indicated that the beta-power decrease was around the parietal-posterior regions, mainly in the precuneus. We propose that beta-band desynchronization in the parietal-posterior regions reflects the disambiguation process, and our findings provide additional support for the theory that beta-band activity is related to the transition of cognitive state.

  11. Figure of merit for task-based assessment of frequency-domain diffusive imaging.

    PubMed

    Kang, DongYel; Kupinski, Matthew A

    2013-01-15

    A figure of merit (FOM) for frequency-domain diffusive imaging (FDDI) is theoretically developed adapting the concept of Hotelling observer signal-to-noise ratio. Different from conventionally used FOMs for FDDI, the newly developed FOM considers diffused intensities, modulation amplitudes, and phases in combination. The FOM applied to Monte Carlo simulations of signal- and background-known-exactly problems shows unique characteristics that are in agreement with findings in the literature. We believe that a task based assessment using the FOM improves the characterization of FDDI systems and allows for complete system optimization.

  12. Increased alpha band activity indexes inhibitory competition across a border during figure assignment.

    PubMed

    Sanguinetti, Joseph L; Trujillo, Logan T; Schnyer, David M; Allen, John J B; Peterson, Mary A

    2016-09-01

    Figure-ground assignment is thought to entail inhibitory competition between potential objects on opposite sides of a shared border; the winner is perceived as the figure, and the loser as the shapeless ground. Computational models and response time measures support this understanding but to date no online measure of inhibitory competition during figure-ground assignment has been reported. The current study assays electroencephalogram (EEG) alpha power as a measure of inhibitory competition during figure-ground assignment. Activity in the EEG alpha band has been linked to functional inhibition in the brain, and it has been proposed that increased alpha power reflects increased inhibition. In 2 experiments participants viewed silhouettes designed so that the insides would be perceived as figures. Real-world silhouettes depicted namable objects. Novel silhouettes depicted novel objects on the insides of their borders, but varied in the amount of hypothesized cross-border competition for figural status: In "Low-Competition" silhouettes, the borders suggested novel objects on the outside as well as on the inside. In "High-Competition" silhouettes the borders suggested portions of real-world objects on the outside; these compete with the figural properties favoring the inside as figure. Participants accurately categorized both types of novel silhouettes as "novel" objects and were unaware of the real world objects suggested on the outside of the High-Competition silhouettes. In both experiments, we observed more alpha power while participants viewed High- rather than Low-Competition novel silhouettes. These are the first results to show via an online index of neural activity that figure assignment entails inhibitory competition.

  13. Analysis of Active Figure Control Effects on Mounting Strategy for X-Ray Optics

    NASA Technical Reports Server (NTRS)

    Kolodziejczak, Jeffrey J.; Roche, Jacqueline M.; O'Dell, Stephen L.; Ramsey, Brian D.; Elsner, Ryan F.; Gubarev, Mikhail V.; Weisskopf, Martin C.

    2014-01-01

    As part of ongoing development efforts at MSFC, we have begun to investigate mounting strategies for highly nested x-ray optics in both full-shell and segmented configurations. The analytical infrastructure for this effort also lends itself to investigation of active strategies. We expect that a consequence of active figure control on relatively thin substrates is that errors are propagated to the edges, where they might affect the effective precision of the mounting points. Based upon modeling, we describe parametrically, the conditions under which active mounts are preferred over fixed ones, and the effect of active figure corrections on the required number, locations, and kinematic characteristics of mounting points.

  14. Active Figure Control Effects on Mounting Strategy for X-Ray Optics

    NASA Technical Reports Server (NTRS)

    Kolodziejczak, Jeffery J.; Atkins, Carolyn; Roche, Jacqueline M.; ODell, Stephen L.; Ramsey, Brian D.; Elsner, Ronald F.; Weisskopf, Martin C.; Gubarev, Mikhail V.

    2014-01-01

    As part of ongoing development efforts at MSFC, we have begun to investigate mounting strategies for highly nested xray optics in both full-shell and segmented configurations. The analytical infrastructure for this effort also lends itself to investigation of active strategies. We expect that a consequence of active figure control on relatively thin substrates is that errors are propagated to the edges, where they might affect the effective precision of the mounting points. Based upon modeling, we describe parametrically, the conditions under which active mounts are preferred over fixed ones, and the effect of active figure corrections on the required number, locations, and kinematic characteristics of mounting points.

  15. Figures of merit for optimizing imaging systems on joint estimation/detection tasks

    NASA Astrophysics Data System (ADS)

    Clarkson, Eric

    2016-05-01

    Previously published work on joint estimation/detection tasks has focused on the area under the Estimation Receiver Operating Characteristic (EROC) curve as a figure of merit for these tasks in imaging. A brief discussion of this concept and the corresponding ideal observer is included here, but the main focus is on three new approaches for system optimization on these joint tasks. One of these approaches is a generalization of Shannon Task Specific Information (TSI) to this setting. The form of this TSI is used to show that a system optimized for the joint task will not in general be optimized for the detection task alone. Another figure of merit for these joint tasks is the Bayesian Risk, where a cost is assigned to all detection outcomes and to the estimation errors, and then averaged over all sources of randomness in the object ensemble and the imaging system. The ideal observer in this setting, which minimizes the risk, is shown to be the same as the ideal EROC observer, which maximizes the area under the EROC curve. It is also shown that scaling the estimation cost function upwards, i.e making the estimation task more important, degrades the performance of this ideal observer on the detection component of the joint task. Finally we generalize these concepts to the idea of Estimation/Detection Information Tradeoff (EDIT) curves which can be used to quantify the tradeof between estimation performance and detection performance in system design.

  16. Image, measure, figure: a critical discourse analysis of nursing practices that develop children.

    PubMed

    Einboden, Rochelle; Rudge, Trudy; Varcoe, Colleen

    2013-07-01

    Motivated by discourses that link early child development and health, nurses engage in seemingly benign surveillance of children. These practices are based on knowledge claims and technologies of developmental science, which remain anchored in assumptions of the child body as an incomplete form with a universal developmental trajectory and inherent potentiality. This paper engages in a critical discursive analysis, drawing on Donna Haraway's conceptualizations of technoscience and figuration. Using a contemporary developmental screening tool from nursing practice, this analysis traces the effects of this tool through production, transformation, distribution, and consumption. It reveals how the techniques of imaging, abstraction, and measurement collide to fix the open, transformative child body in a figuration of the developing child. This analysis also demonstrates how technobiopower infuses nurses' understandings of children and structures developmentally appropriate expectations for children, parents, and nurses. Furthermore, it describes how practices that claim to facilitate healthy child development may inversely deprive children of agency and foster the production of normal or ideal children. An alternative ontological perspective is offered as a challenge to the individualism of developmental models and other dominant ideologies of development, as well as practices associated with these ideologies. In summary, this analysis argues that nurses must pay closer attention to how technobiopower infuses practices that monitor and promote child development. Fostering a critical understanding of the harmful implications of these practices is warranted and offers the space to conceive of human development in alternate and exciting ways.

  17. [Estimation of appropriate dose for computed radiography by the threshold value of the image quality figure].

    PubMed

    Mochizuki, Yasuo; Abe, Shinji; Yamaguchi, Kojirou

    2009-04-20

    We estimated the optimum dose for imaging with a computed radiography (CR) system at two different pixel sizes based on the area under curve (AUC) in receiver operating characteristic (ROC) analysis and image quality figure (IQF). Samples for ROC analysis were prepared as follows. Acryl beads, 2.0 mm in diameter, were placed on a 50.0 mm tough water phantom that was fitted with a 20.0 mm Al filter (SID 200 cm, tube voltage 80 kV). The dose level at which the film density of the screen-film system (SRO250/SRG) was 1.0+/-0.05 served as the reference dose (0.69microC/kg). Five samples were prepared by multiplying the reference dose by 1/4, 1/2, 1, 2, and 4. The samples for image quality evaluation on the basis of IQF were prepared under identical conditions. A contrast-detail (C-D) phantom was placed on a 50.0 mm tough water phantom and images were taken. The contrast threshold of these samples was determined by 10 film readers, the same as those for the ROC analysis. When the significance of differences in the AUC was tested by the paired t-test (two-sided) and the Jackknife method, significant differences were noted between the reference dose and the 1/4 or 4-times dose at the standard pixel size (0.175 mm) and smaller pixel size (0.0875 mm) size, while no significant difference was noted between the reference dose and the 1/2 or 2-times dose. In terms of IQF, no significant difference was noted between standard and smaller pixel sizes (paired t-test). The IQF data indicate that the dose level for imaging with CR can be reduced by about 30% from the reference dose.

  18. Development of Automated Tracking System with Active Cameras for Figure Skating

    NASA Astrophysics Data System (ADS)

    Haraguchi, Tomohiko; Taki, Tsuyoshi; Hasegawa, Junichi

    This paper presents a system based on the control of PTZ cameras for automated real-time tracking of individual figure skaters moving on an ice rink. In the video images of figure skating, irregular trajectories, various postures, rapid movements, and various costume colors are included. Therefore, it is difficult to determine some features useful for image tracking. On the other hand, an ice rink has a limited area and uniform high intensity, and skating is always performed on ice. In the proposed system, an ice rink region is first extracted from a video image by the region growing method, and then, a skater region is extracted using the rink shape information. In the camera control process, each camera is automatically panned and/or tilted so that the skater region is as close to the center of the image as possible; further, the camera is zoomed to maintain the skater image at an appropriate scale. The results of experiments performed for 10 training scenes show that the skater extraction rate is approximately 98%. Thus, it was concluded that tracking with camera control was successful for almost all the cases considered in the study.

  19. Segmented Mirror Image Degradation Due to Surface Dust, Alignment and Figure

    NASA Technical Reports Server (NTRS)

    Schreur, Julian J.

    1999-01-01

    In 1996 an algorithm was developed to include the effects of surface roughness in the calculation of the point spread function of a telescope mirror. This algorithm has been extended to include the effects of alignment errors and figure errors for the individual elements, and an overall contamination by surface dust. The final algorithm builds an array for a guard-banded pupil function of a mirror that may or may not have a central hole, a central reflecting segment, or an outer ring of segments. The central hole, central reflecting segment, and outer ring may be circular or polygonal, and the outer segments may have trimmed comers. The modeled point spread functions show that x-tilt and y-tilt, or the corresponding R-tilt and theta-tilt for a segment in an outer ring, is readily apparent for maximum wavefront errors of 0.1 lambda. A similar sized piston error is also apparent, but integral wavelength piston errors are not. Severe piston error introduces a focus error of the opposite sign, so piston could be adjusted to compensate for segments with varying focal lengths. Dust affects the image principally by decreasing the Strehl ratio, or peak intensity of the image. For an eight-meter telescope a 25% coverage by dust produced a scattered light intensity of 10(exp -9) of the peak intensity, a level well below detectability.

  20. Uncooled microbolometer trade off or new figure of merit for uncooled imager

    NASA Astrophysics Data System (ADS)

    Crastes, Arnaud; Tissot, Jean Luc

    2007-04-01

    NETD is not the sole parameter to characterize microbolometer array and other parameters are as important as this one, indeed when a products comparison is done, NETD values but not, systematically, technology data (such as thermal time constant...) and typical imager parameters can be used. However, as NETD is strongly dependant on the thermal time constant, it's important to compare microbolometer in the same conditions to evaluate advantages and drawbacks. This paper deals with the important parameters to compare microbolometer devices and propose a figure of merit to take into account thermal sensitivity as well as imager characterization: such as MTF, fill factor and thermal time constant, which are often forgotten in the data products; for example, a die with a NETD around 10mK and thermal time constant around 40ms will not be compliant with a 100 Hz frame rate and has to be compared with a 40mK, τ=10ms component. The important point is to compare the right criteria and to make the best choice for the application. An example will be also presented to see how to choose an uncooled array for a given application.

  1. Solving problems on base of concepts formalization of language image and figurative meaning of the natural-language constructs

    NASA Astrophysics Data System (ADS)

    Bisikalo, Oleg V.; Cieszczyk, Sławomir; Yussupova, Gulbahar

    2015-12-01

    Building of "clever" thesaurus by algebraic means on base of concepts formalization of language image and figurative meaning of the natural-language constructs in the article are proposed. A formal theory based on a binary operator of directional associative relation is constructed and an understanding of an associative normal form of image constructions is introduced. A model of a commutative semigroup, which provides a presentation of a sentence as three components of an interrogative language image construction, is considered.

  2. One Size Doesn't Fit All: New Continua of Figure Drawings and Their Relation to Ideal Body Image

    ERIC Educational Resources Information Center

    Novella, Jocelyn; Gosselin, Jennifer T.; Danowski, Debbie

    2015-01-01

    Objective: This study introduces a new figure drawing measure, the Presentation of Images on a Continuum Scale (PICS), which includes continua of bodies from thin to obese and thin to muscular for both men and women. Participants: Participants were undergraduate students from a private, Catholic university in Connecticut. The data were collected…

  3. Information capacity as a figure of merit for spectral imagers: the trade-off between resolution and coregistration.

    PubMed

    Skauli, Torbjørn

    2013-03-01

    The performance of spectral imagers is customarily described by several characteristics including resolution, noise, and coregistration. These must be traded off against each other in a practical imager design. This paper proposes a way to use the information capacity, in an information-theoretic sense, as a figure of merit for spectral imagers. In particular, it is shown how a metric [Opt. Express 20, 918 (2012)] can be used to incorporate coregistration performance in a definition of total noise, which in turn can be used in the definition of information capacity. As an example, it is shown how the information capacity can be used to optimize the pixel size in a simple case that can be treated analytically. Generally, the information capacity is attractive as a fundamental, application-independent figure of merit for spectral imager optimization and benchmarking.

  4. A novel figure panel classification and extraction method for document image understanding.

    PubMed

    Yuan, Xiaohui; Ang, Dongyu

    2014-01-01

    With the availability of full-text documents in many online databases, the paradigm of biomedical literature mining and document understanding has shifted to analysis of both text and figures to derive implicit messages that are unforeseen with text mining only. To enable automatic, massive processing, a key step is to extract and parse figures embedded in papers. In this paper, we present a novel model-driven, hierarchical method to classify and extract panels from figures in scientific papers. Our method consists of two integrated components: figure (or panel) classification and panel segmentation. Figure classification evaluates each panel and decides the existence of photographs and drawings. Mixtures of photographs and non-photographs are divided into subfigures. The splitting process repeats until no further panel collage can be identified. Detection of highlighted views is addressed with Hough space analysis. Using reconstruction from Hough peaks, enclosed panels are retrieved and saved into separate files. Experiments were conducted with a total of 360 figures extracted from two sets of papers that are retrieved with difference sets of keywords. Experimental results demonstrated that our method successfully segmented figures and extracted photographs and non-photographs with high accuracy and robustness. In addition, our method was able to identify zoom-in views that are superimposed on the original photographs. The efficiency of our method allows online implementation.

  5. Correcting Surface Figure Error in Imaging Satellites Using a Deformable Mirror

    DTIC Science & Technology

    2013-12-01

    is relayed to the deformable mirror by two 60 mm focal length achromatic doublet relays. From the DM, two 175 mm focal length achromatic doublets...mirror segment on the Naval Postgraduate School Segmented Mirror Telescope to test the ability of a deformable mirror to correct inherent surface figure...deformable mirror to correct surface figure error on the Segmented Mirror Telescope mirror segments to achieve 55% root mean square improvement for

  6. Looking at Images with Human Figures: Comparison between Autistic and Normal Children.

    ERIC Educational Resources Information Center

    van der Geest, J. N.; Kemner, C.; Camfferman, G.; Verbaten, M. N.; van Engeland, H.

    2002-01-01

    In this study, the looking behavior of 16 autistic and 14 non-autistic children toward cartoon-like scenes that included a human figure was measured quantitatively using an infrared eye-tracking device. Fixation behavior of autistic children was similar to that of their age-and IQ-matched normal peers. Results do not support the idea that autistic…

  7. Activation of the attachment system in adulthood: threat-related primes increase the accessibility of mental representations of attachment figures.

    PubMed

    Mikulincer, Mario; Gillath, Omri; Shaver, Phillip R

    2002-10-01

    Three studies explored the effects of subliminal threat on the activation of representations of attachment figures. This accessibility was measured in a lexical decision task and a Stroop task following threat- or neutral-word primes, and was compared with the accessibility of representations of other close persons, known but not close persons, and unknown persons. Participants also reported on their attachment style. Threat primes led to increased accessibility of representations of attachment figures. This effect was specific to attachment figures and was replicated across tasks and experiments. Attachment anxiety heightened accessibility of representations of attachment figures even in neutral contexts, whereas attachment avoidance inhibited this activation when the threat prime was the word separation. These effects were not, explained by trait anxiety. The discussion focuses on the dynamics of attachment-system activation in adulthood.

  8. Activating Attachments Reduces Memories of Traumatic Images

    PubMed Central

    Foord, Rachael

    2016-01-01

    Emotional memories, and especially intrusive memories, are a common feature of many psychological disorders, and are overconsolidated by stress. Attachment theory posits that activation of mental representations of attachment figures can reduce stress and boost coping. This study tested the proposition that attachment activation would reduce consolidation of emotional and intrusive memories. Sixty-seven undergraduate students viewed subliminal presentations of traumatic and neutral images, which were preceded by subliminal presentations of either attachment-related images or non-attachment-related images; free recall and intrusive memories were assessed two days later. Participants with low avoidant attachment tendencies who received the attachment primes recalled fewer memories and reported fewer intrusions than those who received the non-attachment primes. Unexpectedly, those with high anxious attachment tendencies reported fewer memories. These findings generally accord with attachment theory, and suggest that consolidation of emotional memories can be moderated by activation of attachment representations. PMID:27631498

  9. Looking at images with human figures: comparison between autistic and normal children.

    PubMed

    van der Geest, J N; Kemner, C; Camfferman, G; Verbaten, M N; van Engeland, H

    2002-04-01

    Based on clinical observations of abnormal gaze behavior of autistic children, it has been suggested that autistic children have a problem in processing social information. Several studies on eye movements have indeed found indications that children with autism show particularly abnormal gaze behavior in relation to social stimuli. However, the methodology used in such investigations did not allow for precise gaze analysis. In the present study, the looking behavior of autistic children toward cartoon-like scenes that included a human figure was measured quantitatively using an infrared eye-tracking device. Fixation behavior of autistic children was similar to that of their age- and IQ-matched normal peers. These results do not support the notion that autistic children have a specific problem in processing socially loaded visual stimuli. Also, there is no indication for an abnormality in gaze behavior in relation to neutral objects. It is suggested that the often-reported abnormal use of gaze in everyday life is not related to the nature of the visual stimuli but that other factors, like social interaction, may play a decisive role.

  10. Figure of merit for macrouniformity based on image quality ruler evaluation and machine learning framework

    NASA Astrophysics Data System (ADS)

    Wang, Weibao; Overall, Gary; Riggs, Travis; Silveston-Keith, Rebecca; Whitney, Julie; Chiu, George; Allebach, Jan P.

    2013-01-01

    Assessment of macro-uniformity is a capability that is important for the development and manufacture of printer products. Our goal is to develop a metric that will predict macro-uniformity, as judged by human subjects, by scanning and analyzing printed pages. We consider two different machine learning frameworks for the metric: linear regression and the support vector machine. We have implemented the image quality ruler, based on the recommendations of the INCITS W1.1 macro-uniformity team. Using 12 subjects at Purdue University and 20 subjects at Lexmark, evenly balanced with respect to gender, we conducted subjective evaluations with a set of 35 uniform b/w prints from seven different printers with five levels of tint coverage. Our results suggest that the image quality ruler method provides a reliable means to assess macro-uniformity. We then defined and implemented separate features to measure graininess, mottle, large area variation, jitter, and large-scale non-uniformity. The algorithms that we used are largely based on ISO image quality standards. Finally, we used these features computed for a set of test pages and the subjects' image quality ruler assessments of these pages to train the two different predictors - one based on linear regression and the other based on the support vector machine (SVM). Using five-fold cross-validation, we confirmed the efficacy of our predictor.

  11. Imaging nervous system activity.

    PubMed

    Fields, R D; O'Donovan, M J

    2001-05-01

    Optical imaging methods rely upon visualization of three types of signals: (1) intrinsic optical signals, including light scattering and reflectance, birefringence, and spectroscopic changes of intrinsic molecules, such as NADH or oxyhemoglobin; (2) changes in fluorescence or absorbance of voltage-sensitive membrane dyes; and (3) changes in fluorescence or absorbance of calcium-sensitive indicator dyes. Of these, the most widely used approach is fluorescent microscopy of calcium-sensitive dyes. This unit describes protocols for the use of calcium-sensitive dyes and voltage-dependent dyes for studies of neuronal activity in culture, tissue slices, and en-bloc preparations of the central nervous system.

  12. Optical Modeling Activities for NASA's James Webb Space Telescope (JWST). 3; Wavefront Aberrations due to Alignment and Figure Compensation

    NASA Technical Reports Server (NTRS)

    Howard, Joseph

    2007-01-01

    This is part three of a series describing the ongoing optical modeling activities for James Webb Space Telescope (JWST). The first two discussed modeling JWST on-orbit performance using wavefront sensitivities to predict line of sight motion induced blur, and stability during thermal transients. The work here investigates the aberrations resulting from alignment and figure compensation of the controllable degrees of freedom (primary and secondary mirrors), which may be encountered during ground alignment and on-orbit commissioning of the observatory. The optical design of the telescope is a three-mirror anastigmat, with an active fold mirror at the exit pupil for fine guiding. The primary mirror is over 6.5 meters in diameter, and is composed of 18 hexagonal segments that can individually positioned on hexapods, as well as compensated for radius of curvature. This effectively gives both alignment and figure control of the primary mirror. The secondary mirror can be moved in rigid body only, giving alignment control of the telescope. The tertiary mirror is fixed, however, as well as the location of the science instrumentation. Simulations are performed of various combinations of active alignment corrections of component figure errors, and of primary mirror figure corrections of alignment errors. Single field point and moderate field knowledge is assumed in the corrections. Aberrations over the field are reported for the varying cases, and examples presented.

  13. The role of oscillatory brain activity in object processing and figure-ground segmentation in human vision.

    PubMed

    Kinsey, K; Anderson, S J; Hadjipapas, A; Holliday, I E

    2011-03-01

    The perception of an object as a single entity within a visual scene requires that its features are bound together and segregated from the background and/or other objects. Here, we used magnetoencephalography (MEG) to assess the hypothesis that coherent percepts may arise from the synchronized high frequency (gamma) activity between neurons that code features of the same object. We also assessed the role of low frequency (alpha, beta) activity in object processing. The target stimulus (i.e. object) was a small patch of a concentric grating of 3c/°, viewed eccentrically. The background stimulus was either a blank field or a concentric grating of 3c/° periodicity, viewed centrally. With patterned backgrounds, the target stimulus emerged--through rotation about its own centre--as a circular subsection of the background. Data were acquired using a 275-channel whole-head MEG system and analyzed using Synthetic Aperture Magnetometry (SAM), which allows one to generate images of task-related cortical oscillatory power changes within specific frequency bands. Significant oscillatory activity across a broad range of frequencies was evident at the V1/V2 border, and subsequent analyses were based on a virtual electrode at this location. When the target was presented in isolation, we observed that: (i) contralateral stimulation yielded a sustained power increase in gamma activity; and (ii) both contra- and ipsilateral stimulation yielded near identical transient power changes in alpha (and beta) activity. When the target was presented against a patterned background, we observed that: (i) contralateral stimulation yielded an increase in high-gamma (>55 Hz) power together with a decrease in low-gamma (40-55 Hz) power; and (ii) both contra- and ipsilateral stimulation yielded a transient decrease in alpha (and beta) activity, though the reduction tended to be greatest for contralateral stimulation. The opposing power changes across different regions of the gamma spectrum with

  14. Occipital network for figure/ground organization.

    PubMed

    Likova, Lora T; Tyler, Christopher W

    2008-08-01

    To study the cortical mechanism of figure/ground categorization in the human brain, we employed fMRI and the temporal-asynchrony paradigm. This paradigm is able to eliminate any differential activation for local stimulus features, and thus to identify only global perceptual interactions. Strong segmentation of the image into different spatial configurations was generated solely from temporal asynchronies between zones of homogeneous dynamic noise. The figure/ground configuration was a single geometric figure enclosed in a larger surround region. In a control condition, the figure/ground organization was eliminated by segmenting the noise field into many identical temporal-asynchrony stripes. The manipulation of the type of perceptual organization triggered dramatic reorganization in the cortical activation pattern. The figure/ground configuration generated suppression of the ground representation (limited to early retinotopic visual cortex, V1 and V2) and strong activation in the motion complex hMT+/V5+; conversely, both responses were abolished when the figure/ground organization was eliminated. These results suggest that figure/ground processing is mediated by top-down suppression of the ground representation in the earliest visual areas V1/V2 through a signal arising in the motion complex. We propose a model of a recurrent cortical architecture incorporating suppressive feedback that operates in a topographic manner, forming a figure/ground categorization network distinct from that for "pure" scene segmentation and thus underlying the perceptual organization of dynamic scenes into cognitively relevant components.

  15. The Ruff Figural Fluency Test: heightened right frontal lobe delta activity as a function of performance.

    PubMed

    Foster, Paul S; Williamson, John B; Harrison, David W

    2005-06-01

    Research has indicated that the Ruff Figural Fluency Test [RFFT; Ruff, R. M., Light, R. H., & Evans, R. W. (1987). The Ruff Figural Fluency Test: A normative study with adults. Developmental Neuropsychology, 3, 37-51] is sensitive to right frontal lobe functioning. Indeed, research has differentiated between patients with left or right frontal lobe lesions using performance on the RFFT [Ruff, R. M., Allen, C. C., Farrow, C. E., Niemann, H., & Wylie, T. (1994). Figural fluency: Differential impairment in patients with left versus right frontal lobe lesions. Archives of Clinical Neuropsychology, 9, 41-55]. The present investigation used quantitative electroencephalography to test further whether the RFFT was sensitive to right frontal lobe functioning among a group of individuals with no history of head injury. To meet this objective, the RFFT was administered to a group of 45 right-handed men with no history of significant head injury or cerebral dysfunction. Delta magnitude (muV) at three right frontal electrode sites (FP2, F4, F8) was then used to compare those who performed the best (High Fluency) with those who performed the worst (Low Fluency) on the RFFT. The findings indicated heightened right frontal delta magnitude for the Low Fluency group relative to the High Fluency group at the F2 and F8 right frontal electrode sites. Thus, the present findings provide further support for the contention that the RFFT is sensitive to right frontal lobe functioning, even among those with no history of head injury.

  16. Submillimeter Confocal Imaging Active Module

    NASA Technical Reports Server (NTRS)

    Hong, John; Mehdi, Imran; Siegel, Peter; Chattopadhyay, Goutam; Cwik, Thomas; Rowell, Mark; Hacker, John

    2009-01-01

    The term submillimeter confocal imaging active module (SCIAM) denotes a proposed airborne coherent imaging radar system that would be suitable for use in reconnaissance, surveillance, and navigation. The development of the SCIAM would include utilization and extension of recent achievements in monolithic microwave integrated circuits capable of operating at frequencies up to and beyond a nominal radio frequency of 340 GHz. Because the SCIAM would be primarily down-looking (in contradistinction to primarily side-looking), it could be useful for imaging shorter objects located between taller ones (for example, objects on streets between buildings). The SCIAM would utilize a confocal geometry to obtain high cross-track resolution, and would be amenable to synthetic-aperture processing of its output to obtain high along-track resolution. The SCIAM (see figure) would include multiple (two in the initial version) antenna apertures, separated from each other by a cross-track baseline of suitable length (e.g., 1.6 m). These apertures would both transmit the illuminating radar pulses and receive the returns. A common reference oscillator would generate a signal at a controllable frequency of (340 GHz + (Delta)f)/N, where (Delta)f is an instantaneous swept frequency difference and N is an integer. The output of this oscillator would be fed to a frequency- multiplier-and-power-amplifier module to obtain a signal, at 340 GHz + (Delta)f, that would serve as both the carrier signal for generating the transmitted pulses and a local-oscillator (LO) signal for a receiver associated with each antenna aperture. Because duplexers in the form of circulators or transmit/receive (T/R) switches would be lossy and extremely difficult to implement, the antenna apertures would be designed according to a spatial-diplexing scheme, in which signals would be coupled in and out via separate, adjacent transmitting and receiving feed horns. This scheme would cause the transmitted and received beams

  17. Go Figure.

    ERIC Educational Resources Information Center

    Greenman, Geri

    2000-01-01

    Describes the first assignment for an intermediate oil painting class in which the students painted the human figure. Explains that the assignment involved three techniques: (1) abstract application of acrylic paint; (2) oil "Paintstiks" from Shiva; and (3) a final layer of actual oil paint. (CMK)

  18. False memory for idiomatic expressions in younger and older adults: evidence for indirect activation of figurative meanings

    PubMed Central

    Coane, Jennifer H.; Sánchez-Gutiérrez, Claudia; Stillman, Chelsea M.; Corriveau, Jennifer A.

    2014-01-01

    Idiomatic expressions can be interpreted literally or figuratively. These two meanings are often processed in parallel or very rapidly, as evidenced by online measures of idiomatic processing. Because in many cases the figurative meaning cannot be derived from the component lexical elements and because of the speed with which this meaning is accessed, it is assumed such meanings are stored in semantic memory. In the present study, we examined how literal equivalents and intact idiomatic expressions are stored in memory and whether episodic memory traces interact or interfere with semantic-level representations and vice versa. To examine age-invariance, younger and older adults studied lists of idioms and literal equivalents. On a recognition test, some studied items were presented in the alternative form (e.g., if the idiom was studied, its literal equivalent was tested). False alarms to these critical items suggested that studying literal equivalents activates the idiom from which they are derived, presumably due to spreading activation in lexical/semantic networks, and results in high rates of errors. Importantly, however, the converse (false alarms to literal equivalents after studying the idiom) were significantly lower, suggesting an advantage in storage for idioms. The results are consistent with idiom processing models that suggest obligatory access to figurative meanings and that this access can also occur indirectly, through literal equivalents. PMID:25101030

  19. False memory for idiomatic expressions in younger and older adults: evidence for indirect activation of figurative meanings.

    PubMed

    Coane, Jennifer H; Sánchez-Gutiérrez, Claudia; Stillman, Chelsea M; Corriveau, Jennifer A

    2014-01-01

    Idiomatic expressions can be interpreted literally or figuratively. These two meanings are often processed in parallel or very rapidly, as evidenced by online measures of idiomatic processing. Because in many cases the figurative meaning cannot be derived from the component lexical elements and because of the speed with which this meaning is accessed, it is assumed such meanings are stored in semantic memory. In the present study, we examined how literal equivalents and intact idiomatic expressions are stored in memory and whether episodic memory traces interact or interfere with semantic-level representations and vice versa. To examine age-invariance, younger and older adults studied lists of idioms and literal equivalents. On a recognition test, some studied items were presented in the alternative form (e.g., if the idiom was studied, its literal equivalent was tested). False alarms to these critical items suggested that studying literal equivalents activates the idiom from which they are derived, presumably due to spreading activation in lexical/semantic networks, and results in high rates of errors. Importantly, however, the converse (false alarms to literal equivalents after studying the idiom) were significantly lower, suggesting an advantage in storage for idioms. The results are consistent with idiom processing models that suggest obligatory access to figurative meanings and that this access can also occur indirectly, through literal equivalents.

  20. Activation in a frontoparietal cortical network underlies individual differences in the performance of an embedded figures task.

    PubMed

    Walter, Elizabeth; Dassonville, Paul

    2011-01-01

    The Embedded Figures Test (EFT) requires observers to search for a simple geometric shape hidden inside a more complex figure. Surprisingly, performance in the EFT is negatively correlated with susceptibility to illusions of spatial orientation, such as the Roelofs effect. Using fMRI, we previously demonstrated that regions in parietal cortex are involved in the contextual processing associated with the Roelofs task. In the present study, we found that similar parietal regions (superior parietal cortex and precuneus) were more active during the EFT than during a simple matching task. Importantly, these parietal activations overlapped with regions found to be involved during contextual processing in the Roelofs illusion. Additional parietal and frontal areas, in the right hemisphere, showed strong correlations between brain activity and behavioral performance during the search task. We propose that the posterior parietal regions are necessary for processing contextual information across many different, but related visuospatial tasks, with additional parietal and frontal regions serving to coordinate this processing in participants proficient in the task.

  1. Enhancement of figural creativity by motor activation: effects of unilateral hand contractions on creativity are moderated by positive schizotypy.

    PubMed

    Rominger, Christian; Papousek, Ilona; Fink, Andreas; Weiss, Elisabeth M

    2014-01-01

    Creativity is an important trait necessary to achieve innovations in science, economy, arts and daily life. Therefore, the enhancement of creative performance is a significant field of investigation. A recent experiment showed enhanced verbal creativity after unilateral left-hand contractions, which was attributed to elevated activation of the right hemisphere. The present study aimed to extend these findings to the domain of figural creativity. Furthermore, as creativity and positive schizotypy may share some neurobiological underpinnings associated with the right hemisphere, we studied the potential moderating effect of positive schizotypy on the effects of the experimental modification of relative hemispheric activation on creativity. In a gender-balanced sample (20 men and 20 women), squeezing a hand gripper with the left hand enhanced figural creativity on the Torrance Test of Creative Thinking compared to squeezing the gripper with the right hand. However, this was only true when positive schizotypy was low. The moderating effect of schizotypy may be produced by relatively greater activity of certain parts of the right hemisphere being a shared neuronal correlate of creativity and positive schizotypy.

  2. Movement Actors in the Education Bureaucracy: The Figured World of Activity Based Learning in Tamil Nadu

    ERIC Educational Resources Information Center

    Niesz, Tricia; Krishnamurthy, Ramchandar

    2014-01-01

    Tamil Nadu has gained international recognition for reforming its government school classrooms into active, child-centered learning environments. Our exploration of the history of the Activity Based Learning movement suggests that this reform was achieved by social movement actors serving in and through the state's administration. Participants in…

  3. Figure Analysis: A Teaching Technique to Promote Visual Literacy and Active Learning

    ERIC Educational Resources Information Center

    Wiles, Amy M.

    2016-01-01

    Learning often improves when active learning techniques are used in place of traditional lectures. For many of these techniques, however, students are expected to apply concepts that they have already grasped. A challenge, therefore, is how to incorporate active learning into the classroom of courses with heavy content, such as molecular-based…

  4. Active Imaging through Cirrus Clouds.

    PubMed

    Landesman, B; Kindilien, P; Pierson, R; Matson, C; Mosley, D

    1997-11-24

    The presence of clouds of ice particles in the uplink and downlink path of an illumination beam can severely impede the performance of an active imaging system. Depending on the optical depth of the cloud, i.e., its density and depth, the beam can be completely scattered and extinguished, or the beam can pass through the cloud with some fraction attenuated, scattered, and depolarized. In particular, subvisual cirrus clouds, i.e., high, thin cirrus clouds that cannot be observed from the ground, can affect the properties and alignment of both uplink and downlink beams. This paper discusses the potential for active imaging in the presence of cirrus clouds. We document field data results from an active imaging experiment conducted several years ago, which the authors believe to show the effects of cirrus clouds on an active imaging system. To verify these conclusions, we include the results of a simulation of the interaction of a coherent illumination scheme with a cirrus cloud.

  5. Sport for All: Physical Activity and the Prevention of Disease. Facts and Figures.

    ERIC Educational Resources Information Center

    Reville, Ph.

    The material presented in this booklet is concerned with the impact of physical activity practiced by the general public, irrespective of age and sex, of various North American and European countries. Major emphasis is on the individual's physical health and susceptibility to disease. Chapter one discusses diseases which occur most frequently in…

  6. Active spectral imaging and mapping

    NASA Astrophysics Data System (ADS)

    Steinvall, Ove

    2014-04-01

    Active imaging and mapping using lasers as illumination sources have been of increasing interest during the last decades. Applications range from defense and security, remote sensing, medicine, robotics, and others. So far, these laser systems have mostly been based on a fix wavelength laser. Recent advances in lasers enable emission of tunable, multiline, or broadband emission, which together with the development of array detectors will extend the capabilities of active imaging and mapping. This paper will review some of the recent work on active imaging mainly for defense and security and remote sensing applications. A short survey of basic lidar relations and present fix wavelength laser systems is followed by a review of the benefits of adding the spectral dimension to active and/or passive electro-optical systems.

  7. Imaging nervous system activity.

    PubMed

    Fields, Douglas R; Shneider, Neil; Mentis, George Z; O'Donovan, Michael J

    2009-10-01

    This unit describes methods for loading ion- and voltage-sensitive dyes into neurons, with a particular focus on the spinal cord as a model system. In addition, we describe the use of these dyes to visualize neural activity. Although the protocols described here concern spinal networks in culture or an intact in vitro preparation, they can be, and have been, widely used in other parts of the nervous system.

  8. A CMOS Energy Harvesting and Imaging (EHI) Active Pixel Sensor (APS) Imager for Retinal Prosthesis.

    PubMed

    Ay, S U

    2011-12-01

    A CMOS image sensor capable of imaging and energy harvesting on same focal plane is presented for retinal prosthesis. The energy harvesting and imaging (EHI) active pixel sensor (APS) imager was designed, fabricated, and tested in a standard 0.5 μm CMOS process. It has 54 × 50 array of 21 × 21 μm(2) EHI pixels, 10-bit supply boosted (SB) SAR ADC, and charge pump circuits consuming only 14.25 μW from 1.2 V and running at 7.4 frames per second. The supply boosting technique (SBT) is used in an analog signal chain of the EHI imager. Harvested solar energy on focal plane is stored on an off-chip capacitor with the help of a charge pump circuit with better than 70% efficiency. Energy harvesting efficiency of the EHI pixel was measured at different light levels. It was 9.4% while producing 0.41 V open circuit voltage. The EHI imager delivers 3.35 μW of power was delivered to a resistive load at maximum power point operation. The measured pixel array figure of merit (FoM) was 1.32 pW/frame/pixel while imager figure of merit (iFoM) including whole chip power consumption was 696 fJ/pixel/code for the EHI imager.

  9. Figure Analysis: An Implementation Dialogue

    ERIC Educational Resources Information Center

    Wiles, Amy M.

    2016-01-01

    Figure analysis is a novel active learning teaching technique that reinforces visual literacy. Small groups of students discuss diagrams in class in order to learn content. The instructor then gives a brief introduction and later summarizes the content of the figure. This teaching technique can be used in place of lecture as a mechanism to deliver…

  10. Topography of Photosynthetic Activity of Leaves Obtained from Video Images of Chlorophyll Fluorescence 1

    PubMed Central

    Daley, Paul F.; Raschke, Klaus; Ball, J. Timothy; Berry, Joseph A.

    1989-01-01

    The distribution of photosynthetic activity over the area of a leaf and its change with time was determined (at low partial pressure of O2) by recording images of chlorophyll fluorescence during saturating light flashes. Simultaneously, the gas exchange was being measured. Reductions of local fluorescence intensity quantitatively displayed the extent of nonphotochemical quenching; quench coefficients, qN, were computed pixel by pixel. Because rates of photosynthetic electron transport are positively correlated with (1 − qN), computed images of (1 − qN) represented topographies of photosynthetic activity. Following application of abscisic acid to the heterobaric leaves of Xanthium strumarium L., clearly delineated regions varying in nonphotochemical quenching appeared that coincided with areoles formed by minor veins and indicated stomatal closure in groups. Images Figure 2 Figure 4 Figure 6 PMID:16666912

  11. Comparison of Brain Activity Correlating with Self-Report versus Narrative Attachment Measures during Conscious Appraisal of an Attachment Figure

    PubMed Central

    Yaseen, Zimri S.; Zhang, Xian; Muran, J. Christopher; Winston, Arnold; Galynker, Igor I.

    2016-01-01

    Objectives: The Adult Attachment Interview (AAI) has been the gold standard of attachment assessment, but requires special training. The Relationship Scales Questionnaire (RSQ) is a widely used self-report measure. We investigate how each correlates with brain activity during appraisal of subjects’ mothers. Methods: Twenty-eight women were scored on the AAI, RSQ, and mood measures. During functional magnetic resonance imaging, subjects viewed their mothers in neutral-, valence-, and salience-rating conditions. We identified regions where contrasts in brain activity between appraisal and neutral viewing conditions correlated with each measure of attachment after covarying for mood. AAI and RSQ measures were then compared in terms of the extent to which regions of correlating brain activity overlapped with “default mode network” (DMN) vs. executive frontal network (EFN) masks and cortical vs. subcortical masks. Additionally, interactions with mood were examined. Results: Salience and valence processing associated with increased thalamo-striatal, posterior cingulate, and visual cortex activity. Salience processing decreased PFC activity, whereas valence processing increased left insula activity. Activity correlating with AAI vs. RSQ measures demonstrated significantly more DMN and subcortical involvement. Interactions with mood were observed in the middle temporal gyrus and precuneus for both measures. Conclusion: The AAI appears to disproportionately correlate with conscious appraisal associated activity in DMN and subcortical structures, while the RSQ appears to tap EFN structures more extensively. Thus, the AAI may assess more interoceptive, ‘core-self’-related processes, while the RSQ captures higher-order cognitions involved in attachment. Shared interaction effects between mood and AAI and RSQ-measures may suggest that processes tapped by each belong to a common system. PMID:27014022

  12. Images of an Activated Asteroid

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-08-01

    In late April of this year, asteroid P/2016 G1 (PANSTARRS) was discovered streaking through space, a tail of dust extending behind it. What caused this asteroids dust activity?Asteroid or Comet?Images of asteroid P/2016 G1 at three different times: late April, late May, and mid June. The arrow in the center panel points out an asymmetric feature that can be explained if the asteroid initially ejected material in a single direction, perhaps due to an impact. [Moreno et al. 2016]Asteroid P/2016 G1 is an interesting case: though it has the orbital elements of a main-belt asteroid it orbits at just under three times the EarthSun distance, with an eccentricity of e ~ 0.21 its appearance is closer to that of a comet, with a dust tail extending 20 behind it.To better understand the nature and cause of this unusual asteroids activity, a team led by Fernando Moreno (Institute of Astrophysics of Andalusia, in Spain) performed deep observations of P/2016 G1 shortly after its discovery. The team used the 10.4-meter Great Canary Telescope to image the asteroid over the span of roughly a month and a half.A Closer Look at P/2016 G1P/2016 G1 lies in the inner region of the main asteroid belt, so it is unlikely to have any ices that suddenly sublimated, causing the outburst. Instead, Moreno and collaborators suggest that the asteroids tail may have been caused by an impact that disrupted the parent body.To test this idea, the team used computer simulations to model their observations of P/2016 G1s dust tail. Based on their models, they demonstrate that the asteroid was likely activated on February 10 2016 roughly 350 days before it reached perihelion in its orbit and its activity was a short-duration event, lasting only ~24 days. The teams models indicate that over these 24 days, the asteroid lost around 20 million kilograms of dust, and at its maximum activity level, it was ejecting around 8 kg/s!Comparison of the observation from late May (panel a) and two models: one in which

  13. Fueling and imaging brain activation

    PubMed Central

    Dienel, Gerald A

    2012-01-01

    Metabolic signals are used for imaging and spectroscopic studies of brain function and disease and to elucidate the cellular basis of neuroenergetics. The major fuel for activated neurons and the models for neuron–astrocyte interactions have been controversial because discordant results are obtained in different experimental systems, some of which do not correspond to adult brain. In rats, the infrastructure to support the high energetic demands of adult brain is acquired during postnatal development and matures after weaning. The brain's capacity to supply and metabolize glucose and oxygen exceeds demand over a wide range of rates, and the hyperaemic response to functional activation is rapid. Oxidative metabolism provides most ATP, but glycolysis is frequently preferentially up-regulated during activation. Underestimation of glucose utilization rates with labelled glucose arises from increased lactate production, lactate diffusion via transporters and astrocytic gap junctions, and lactate release to blood and perivascular drainage. Increased pentose shunt pathway flux also causes label loss from C1 of glucose. Glucose analogues are used to assay cellular activities, but interpretation of results is uncertain due to insufficient characterization of transport and phosphorylation kinetics. Brain activation in subjects with low blood-lactate levels causes a brain-to-blood lactate gradient, with rapid lactate release. In contrast, lactate flooding of brain during physical activity or infusion provides an opportunistic, supplemental fuel. Available evidence indicates that lactate shuttling coupled to its local oxidation during activation is a small fraction of glucose oxidation. Developmental, experimental, and physiological context is critical for interpretation of metabolic studies in terms of theoretical models. PMID:22612861

  14. All about Lissajous Figures.

    ERIC Educational Resources Information Center

    Greenslade, Thomas B.

    1993-01-01

    Uses diagrams and text to illustrate the use of Lissajous figures (the figures that are traced out when two simple harmonic motions are combined at right angles to each other) in teaching basic physics concepts. Covers the mathematics of the Lissajous Figure; demonstrating Lissajous Figures; and a typical class. (ZWH)

  15. Hinode Captures Images of Solar Active Region

    NASA Video Gallery

    In these images, Hinode's Solar Optical Telescope (SOT) zoomed in on AR 11263 on August 4, 2011, five days before the active region produced the largest flare of this cycle, an X6.9. We show images...

  16. Bilingual and Monolingual Idiom Processing Is Cut from the Same Cloth: The Role of the L1 in Literal and Figurative Meaning Activation

    PubMed Central

    Beck, Sara D.; Weber, Andrea

    2016-01-01

    The present study examines non-native (L2) and native (L1) listeners' access to figurative idiomatic meaning and literal constituent meaning in two cross-modal priming experiments. Proficient German learners of English (L2) and native speakers of American English (L1) responded to English target words preceded by English idioms embedded in non-biasing prime sentences in a lexical decision task. English idioms differed in levels of translatability: Lexical level idioms had word-for-word translation equivalents in German, while post-lexical level idioms had matching idiomatic concepts in German but could not be translated word for word. Target words either related to the figurative meaning of the idiom or related to the literal meaning of the final constituent word of the idiom (e.g., to pull someone's leg, literal target: walk, figurative target: joke). Both L1 and L2 listeners showed facilitatory priming for literally- and figuratively-related target words compared to unrelated control target words, with only marginal differences between the listener groups. No effect of translatability was found; that is, the existence of word-for-word translation equivalents in German neither facilitated nor hindered meaning activation for German L2 listeners. The results are interpreted in the context of L1 and L2 models of idiom processing as well as further relevant translation studies. PMID:27667979

  17. Bilingual and Monolingual Idiom Processing Is Cut from the Same Cloth: The Role of the L1 in Literal and Figurative Meaning Activation.

    PubMed

    Beck, Sara D; Weber, Andrea

    2016-01-01

    The present study examines non-native (L2) and native (L1) listeners' access to figurative idiomatic meaning and literal constituent meaning in two cross-modal priming experiments. Proficient German learners of English (L2) and native speakers of American English (L1) responded to English target words preceded by English idioms embedded in non-biasing prime sentences in a lexical decision task. English idioms differed in levels of translatability: Lexical level idioms had word-for-word translation equivalents in German, while post-lexical level idioms had matching idiomatic concepts in German but could not be translated word for word. Target words either related to the figurative meaning of the idiom or related to the literal meaning of the final constituent word of the idiom (e.g., to pull someone's leg, literal target: walk, figurative target: joke). Both L1 and L2 listeners showed facilitatory priming for literally- and figuratively-related target words compared to unrelated control target words, with only marginal differences between the listener groups. No effect of translatability was found; that is, the existence of word-for-word translation equivalents in German neither facilitated nor hindered meaning activation for German L2 listeners. The results are interpreted in the context of L1 and L2 models of idiom processing as well as further relevant translation studies.

  18. Automatic figure classification in bioscience literature.

    PubMed

    Kim, Daehyun; Ramesh, Balaji Polepalli; Yu, Hong

    2011-10-01

    Millions of figures appear in biomedical articles, and it is important to develop an intelligent figure search engine to return relevant figures based on user entries. In this study we report a figure classifier that automatically classifies biomedical figures into five predefined figure types: Gel-image, Image-of-thing, Graph, Model, and Mix. The classifier explored rich image features and integrated them with text features. We performed feature selection and explored different classification models, including a rule-based figure classifier, a supervised machine-learning classifier, and a multi-model classifier, the latter of which integrated the first two classifiers. Our results show that feature selection improved figure classification and the novel image features we explored were the best among image features that we have examined. Our results also show that integrating text and image features achieved better performance than using either of them individually. The best system is a multi-model classifier which combines the rule-based hierarchical classifier and a support vector machine (SVM) based classifier, achieving a 76.7% F1-score for five-type classification. We demonstrated our system at http://figureclassification.askhermes.org/.

  19. RGB-NIR active gated imaging

    NASA Astrophysics Data System (ADS)

    Spooren, Nick; Geelen, Bert; Tack, Klaas; Lambrechts, Andy; Jayapala, Murali; Ginat, Ran; David, Yaara; Levi, Eyal; Grauer, Yoav

    2016-10-01

    This paper presents multispectral active gated imaging in relation to the transportation and security fields. Active gated imaging is based on a fast gated camera and pulsed illuminator, synchronized in the time domain to provide range based images. We have developed a multispectral pattern deposited on a gated CMOS Image Sensor (CIS) with a pulsed Near Infrared VCSEL module. This paper will cover the component-level description of the multispectral gated CIS including the camera and illuminator units. Furthermore, the design considerations and characterization results of the spectral filters are presented together with a newly developed image processing method.

  20. Perceptual Experience of Visual Motion Activates hMT+ Independently From the Physical Reality: fMRI Insights From the Looming Pinna Figure.

    PubMed

    Budnik, U; Hindi-Attar, C; Hamburger, K; Pinna, B; Hennig, J; Speck, O

    2016-06-03

    The human motion processing area, hMT+, has been labeled the critical neural area for processing of real and illusory visual motion in radial 2D patterns. However, the activation in hMT+ during perception of illusory rotation in the looming double-circular Pinna Figure (PF) generated in 3D space has not been observed yet. To do so, an optic-flow like motion of rings (looming) in PF was generated on a computer screen. A psychophysically precise nulling procedure allowed quantifying the individual amount of the perceived illusory rotation in PF (PI) for each participant. The interpolation of the individual illusory motion parameters created a subjectively non-rotating PF and a physically rotating control stimulus of identical rotary strength as the PI. The physically rotating control was a double-circular figure which diverged from PF only in its arrangement of luminance gradients. In a 3-Tesla scanner, participants were presented with a random order of rotating and non-rotating figures (illusory, real, no rotation, and nulled PI). Both types, illusory and real rotation, when equal in perceptual strength for the observer, were found to be processed by hMT+.

  1. Figure analysis: An implementation dialogue.

    PubMed

    Wiles, Amy M

    2016-07-08

    Figure analysis is a novel active learning teaching technique that reinforces visual literacy. Small groups of students discuss diagrams in class in order to learn content. The instructor then gives a brief introduction and later summarizes the content of the figure. This teaching technique can be used in place of lecture as a mechanism to deliver information to students. Here, a "how to" guide is presented in the form of an in-class dialogue, displaying the difficulties in visual interpretation that some students may experience while figure analysis is being implemented in an upper-level, cell biology course. Additionally, the dialogue serves as a guide for instructors who may implement the active learning technique as they consider how to respond to students' concerns in class. © 2016 by The International Union of Biochemistry and Molecular Biology, 44(4):345-348, 2016.

  2. Incomplete figure perception and invisible masking.

    PubMed

    Chikhman, Valery; Shelepin, Yuri; Foreman, Nigel; Merkuljev, Aleksey; Pronin, Sergey

    2006-01-01

    The Gollin test (measuring recognition thresholds for fragmented line drawings of everyday objects and animals) has traditionally been regarded as a test of incomplete figure perception or 'closure', though there is a debate about how such closure is achieved. Here, figural incompleteness is considered to be the result of masking, such that absence of contour elements of a fragmented figure is the result of the influence of an 'invisible' mask. It is as though the figure is partly obscured by a mask having parameters identical to those of the background. This mask is 'invisible' only consciously, but for the early stages of visual processing it is real and has properties of multiplicative noise. Incomplete Gollin figures were modeled as the figure covered by the mask with randomly distributed transparent and opaque patches. We adjusted the statistical characteristics of the contour image and empty noise patches and processed those using spatial and spatial-frequency measures. Across 73 figures, despite inter-subject variability, mean recognition threshold was always approximately 15% of total contour in naive observers. Recognition worsened with increasing spectral similarity between the figure and the 'invisible' mask. Near threshold, the spectrum of the fragmented image was equally similar to that of the 'invisible' mask and complete image. The correlation between spectral parameters of figures at threshold and complete figures was greatest for figures that were most easily recognised. Across test sessions, thresholds reduced when either figure or mask parameters were familiar. We argue that recognition thresholds for Gollin stimuli in part reflect the extraction of signal from noise.

  3. African American men's perspectives on promoting physical activity: "We're not that difficult to figure out!".

    PubMed

    Friedman, Daniela B; Hooker, Steven P; Wilcox, Sara; Burroughs, Ericka L; Rheaume, Carol E

    2012-01-01

    African American men report poorer health than do White men and have significantly greater odds for developing chronic diseases partly because of limited physical activity. Understanding how to encourage healthy behaviors among African American men will be critical in the development of effective physical activity messages and programs. Guided by principles of cultural sensitivity and social marketing, this research examined middle-aged and older African American men's recommended strategies for promoting physical activity to African American men of their age. The authors report results from 49 interviews conducted with middle-aged (45-64 years) and older (65-84 years) African American men in South Carolina. Four groups of African American men were recruited: middle-aged active men (n = 17), middle-aged inactive men (n = 12), older active men (n = 10), older inactive men (n = 10). Themes related to marketing and recruitment strategies, message content, and spokesperson characteristics emerged and differed by age and physical activity level. Recommended marketing strategies included word of mouth; use of mass media; partnering with churches, businesses, and fraternities; strategic placement of messages; culturally appropriate message framing; and careful attention to selection of program spokespersons. Findings will help in the marketing, design, implementation, and evaluation of culturally appropriate interventions to encourage physical activity among middle-aged and older African American men in the South.

  4. Physical activity - preventive medicine (image)

    MedlinePlus

    Physical activity contributes to health by reducing the heart rate, decreasing the risk for cardiovascular disease, and reducing the amount of bone loss that is associated with age and osteoporosis. Physical ...

  5. Active vs. inactive muscle (image)

    MedlinePlus

    ... may lose 20 to 40 percent of their muscle -- and, along with it, their strength -- as they ... have found that a major reason people lose muscle is because they stop doing everyday activities that ...

  6. Active dictionary learning for image representation

    NASA Astrophysics Data System (ADS)

    Wu, Tong; Sarwate, Anand D.; Bajwa, Waheed U.

    2015-05-01

    Sparse representations of images in overcomplete bases (i.e., redundant dictionaries) have many applications in computer vision and image processing. Recent works have demonstrated improvements in image representations by learning a dictionary from training data instead of using a predefined one. But learning a sparsifying dictionary can be computationally expensive in the case of a massive training set. This paper proposes a new approach, termed active screening, to overcome this challenge. Active screening sequentially selects subsets of training samples using a simple heuristic and adds the selected samples to a "learning pool," which is then used to learn a newer dictionary for improved representation performance. The performance of the proposed active dictionary learning approach is evaluated through numerical experiments on real-world image data; the results of these experiments demonstrate the effectiveness of the proposed method.

  7. Facts and Figures

    MedlinePlus

    ... Saves Lives Facts & Figures My Blood, Your Blood Blood Donation Types Did you know there is more than one type of blood donation? Learn more about blood donation types here. Blood Safety and Testing The blood supply ...

  8. Texture Segregation Causes Early Figure Enhancement and Later Ground Suppression in Areas V1 and V4 of Visual Cortex.

    PubMed

    Poort, Jasper; Self, Matthew W; van Vugt, Bram; Malkki, Hemi; Roelfsema, Pieter R

    2016-10-01

    Segregation of images into figures and background is fundamental for visual perception. Cortical neurons respond more strongly to figural image elements than to background elements, but the mechanisms of figure-ground modulation (FGM) are only partially understood. It is unclear whether FGM in early and mid-level visual cortex is caused by an enhanced response to the figure, a suppressed response to the background, or both.We studied neuronal activity in areas V1 and V4 in monkeys performing a texture segregation task. We compared texture-defined figures with homogeneous textures and found an early enhancement of the figure representation, and a later suppression of the background. Across neurons, the strength of figure enhancement was independent of the strength of background suppression.We also examined activity in the different V1 layers. Both figure enhancement and ground suppression were strongest in superficial and deep layers and weaker in layer 4. The current-source density profiles suggested that figure enhancement was caused by stronger synaptic inputs in feedback-recipient layers 1, 2, and 5 and ground suppression by weaker inputs in these layers, suggesting an important role for feedback connections from higher level areas. These results provide new insights into the mechanisms for figure-ground organization.

  9. See around the corner using active imaging

    NASA Astrophysics Data System (ADS)

    Steinvall, Ove; Elmqvist, Magnus; Larsson, Håkan

    2011-11-01

    This paper investigates the prospects of "seeing around the corner" using active imaging. A monostatic active imaging system offers interesting capabilities in the presence of glossy reflecting objects. Examples of such surfaces are windows in buildings and cars, calm water, signs and vehicle surfaces. During daylight it might well be possible to use mirrorlike reflection by the naked eye or a CCD camera for non-line of sight imaging. However the advantage with active imaging is that one controls the illumination. This will not only allow for low light and night utilization but also for use in cases where the sun or other interfering lights limit the non-line of sight imaging possibility. The range resolution obtained by time gating will reduce disturbing direct reflections and allow simultaneous view in several directions using range discrimination. Measurements and theoretical considerations in this report support the idea of using laser to "see around the corner". Examples of images and reflectivity measurements will be presented together with examples of potential system applications.

  10. Figuring Out Fat and Calories

    MedlinePlus

    ... our growth and activities — everything from solving a math problem to racing up and down the soccer ... The Nemours Foundation, iStock, Getty Images, Corbis, Veer, Science Photo Library, Science Source Images, Shutterstock, and Clipart. ...

  11. Impact of target-to-background ratio, target size, emission scan duration, and activity on physical figures of merit for a 3D LSO-based whole body PET/CT scanner.

    PubMed

    Brambilla, M; Matheoud, R; Secco, C; Sacchetti, G; Comi, S; Rudoni, M; Carriero, A; Inglese, E

    2007-10-01

    The aim of our work is to describe the way in which physical figures of merit such as contrast-to-noise ratio (CNR) behave when varying acquisition parameters such as emission scan duration (ESD) or activity at the start of acquisition (A(acq)) that in clinical practice can be selected by the user, or object properties such as target dimensions or target-to-background (T/B) ratio, which depend uniquely on the intrinsic characteristics of the object being imaged. Figures of merit, used to characterize image quality and quantitative accuracy for a 3D-LSO based PET/CT scanner, were studied as a function of ESD and A(acq) for different target sizes and T/B ratios using a multivariate approach in a wide range of conditions approaching the ones that can be encountered in clinical practice. An annular ring of water bags of 3 cm thickness was fitted over an IEC phantom in order to obtain counting rates similar to those found in average patients. The average scatter fraction (SF) of the modified IEC phantom was similar to the mean SF measured on patients with a similar scanner. A supplemental set of micro-hollow spheres was positioned inside the phantom. The NEMA NU 2-2001 scatter phantom was positioned at the end of the IEC phantom to approximate the clinical situation of having activity that extends beyond the scanner. The phantoms were filled with a solution of water and 18F (12 kBq/mL) and the spheres with various T/B ratios of 22.5, 10.3, and 3.6. Sequential imaging was performed to acquire PET images with varying background activity concentrations of about 12, 9, 6.4, 5.3, and 3.1 kBq/mL, positioned on the linear portion of the phantom's NECR curve, well below peak NECR of 61.2 kcps that is reached at 31.8 kBq/mL. The ESD was set to 1, 2, 3, and 4 min/bed. With T/B ratios of 3.6, 10.3, and 22.5, the 13.0, 8.1, and 6.5 mm spheres were detectable for the whole ranges of background activity concentration and ESD, respectively. The ESD resulted as the most significant

  12. Impact of target-to-background ratio, target size, emission scan duration, and activity on physical figures of merit for a 3D LSO-based whole body PET/CT scanner

    SciTech Connect

    Brambilla, M.; Matheoud, R.; Secco, C.; Sacchetti, G.; Comi, S.; Rudoni, M.; Carriero, A.; Inglese, E.

    2007-10-15

    The aim of our work is to describe the way in which physical figures of merit such as contrast-to-noise ratio (CNR) behave when varying acquisition parameters such as emission scan duration (ESD) or activity at the start of acquisition (A{sub acq}) that in clinical practice can be selected by the user, or object properties such as target dimensions or target-to-background (T/B) ratio, which depend uniquely on the intrinsic characteristics of the object being imaged. Figures of merit, used to characterize image quality and quantitative accuracy for a 3D-LSO based PET/CT scanner, were studied as a function of ESD and A{sub acq} for different target sizes and T/B ratios using a multivariate approach in a wide range of conditions approaching the ones that can be encountered in clinical practice. An annular ring of water bags of 3 cm thickness was fitted over an IEC phantom in order to obtain counting rates similar to those found in average patients. The average scatter fraction (SF) of the modified IEC phantom was similar to the mean SF measured on patients with a similar scanner. A supplemental set of micro-hollow spheres was positioned inside the phantom. The NEMA NU 2-2001 scatter phantom was positioned at the end of the IEC phantom to approximate the clinical situation of having activity that extends beyond the scanner. The phantoms were filled with a solution of water and {sup 18}F (12 kBq/mL) and the spheres with various T/B ratios of 22.5, 10.3, and 3.6. Sequential imaging was performed to acquire PET images with varying background activity concentrations of about 12, 9, 6.4, 5.3, and 3.1 kBq/mL, positioned on the linear portion of the phantom's NECR curve, well below peak NECR of 61.2 kcps that is reached at 31.8 kBq/mL. The ESD was set to 1, 2, 3, and 4 min/bed. With T/B ratios of 3.6, 10.3, and 22.5, the 13.0, 8.1, and 6.5 mm spheres were detectable for the whole ranges of background activity concentration and ESD, respectively. The ESD resulted as the most

  13. Active confocal imaging for visual prostheses.

    PubMed

    Jung, Jae-Hyun; Aloni, Doron; Yitzhaky, Yitzhak; Peli, Eli

    2015-06-01

    There are encouraging advances in prosthetic vision for the blind, including retinal and cortical implants, and other "sensory substitution devices" that use tactile or electrical stimulation. However, they all have low resolution, limited visual field, and can display only few gray levels (limited dynamic range), severely restricting their utility. To overcome these limitations, image processing or the imaging system could emphasize objects of interest and suppress the background clutter. We propose an active confocal imaging system based on light-field technology that will enable a blind user of any visual prosthesis to efficiently scan, focus on, and "see" only an object of interest while suppressing interference from background clutter. The system captures three-dimensional scene information using a light-field sensor and displays only an in-focused plane with objects in it. After capturing a confocal image, a de-cluttering process removes the clutter based on blur difference. In preliminary experiments we verified the positive impact of confocal-based background clutter removal on recognition of objects in low resolution and limited dynamic range simulated phosphene images. Using a custom-made multiple-camera system based on light-field imaging, we confirmed that the concept of a confocal de-cluttered image can be realized effectively.

  14. Active confocal imaging for visual prostheses

    PubMed Central

    Jung, Jae-Hyun; Aloni, Doron; Yitzhaky, Yitzhak; Peli, Eli

    2014-01-01

    There are encouraging advances in prosthetic vision for the blind, including retinal and cortical implants, and other “sensory substitution devices” that use tactile or electrical stimulation. However, they all have low resolution, limited visual field, and can display only few gray levels (limited dynamic range), severely restricting their utility. To overcome these limitations, image processing or the imaging system could emphasize objects of interest and suppress the background clutter. We propose an active confocal imaging system based on light-field technology that will enable a blind user of any visual prosthesis to efficiently scan, focus on, and “see” only an object of interest while suppressing interference from background clutter. The system captures three-dimensional scene information using a light-field sensor and displays only an in-focused plane with objects in it. After capturing a confocal image, a de-cluttering process removes the clutter based on blur difference. In preliminary experiments we verified the positive impact of confocal-based background clutter removal on recognition of objects in low resolution and limited dynamic range simulated phosphene images. Using a custom-made multiple-camera system, we confirmed that the concept of a confocal de-cluttered image can be realized effectively using light field imaging. PMID:25448710

  15. Active segmentation of 3D axonal images.

    PubMed

    Muralidhar, Gautam S; Gopinath, Ajay; Bovik, Alan C; Ben-Yakar, Adela

    2012-01-01

    We present an active contour framework for segmenting neuronal axons on 3D confocal microscopy data. Our work is motivated by the need to conduct high throughput experiments involving microfluidic devices and femtosecond lasers to study the genetic mechanisms behind nerve regeneration and repair. While most of the applications for active contours have focused on segmenting closed regions in 2D medical and natural images, there haven't been many applications that have focused on segmenting open-ended curvilinear structures in 2D or higher dimensions. The active contour framework we present here ties together a well known 2D active contour model [5] along with the physics of projection imaging geometry to yield a segmented axon in 3D. Qualitative results illustrate the promise of our approach for segmenting neruonal axons on 3D confocal microscopy data.

  16. Active-imaging-based underwater navigation

    NASA Astrophysics Data System (ADS)

    Monnin, David; Schmitt, Gwenaël.; Fischer, Colin; Laurenzis, Martin; Christnacher, Frank

    2015-10-01

    Global navigation satellite systems (GNSS) are widely used for the localization and the navigation of unmanned and remotely operated vehicles (ROV). In contrast to ground or aerial vehicles, GNSS cannot be employed for autonomous underwater vehicles (AUV) without the use of a communication link to the water surface, since satellite signals cannot be received underwater. However, underwater autonomous navigation is still possible using self-localization methods which determines the relative location of an AUV with respect to a reference location using inertial measurement units (IMU), depth sensors and even sometimes radar or sonar imaging. As an alternative or a complementary solution to common underwater reckoning techniques, we present the first results of a feasibility study of an active-imaging-based localization method which uses a range-gated active-imaging system and can yield radiometric and odometric information even in turbid water.

  17. Active gated imaging in driver assistance system

    NASA Astrophysics Data System (ADS)

    Grauer, Yoav

    2014-04-01

    In this paper, we shall present the active gated imaging system (AGIS) in relation to the automotive field. AGIS is based on a fast-gated camera and pulsed illuminator, synchronized in the time domain to record images of a certain range of interest. A dedicated gated CMOS imager sensor and near infra-red (NIR) pulsed laser illuminator, is presented in this paper to provide active gated technology. In recent years, we have developed these key components and learned the system parameters, which are most beneficial to nighttime (in all weather conditions) driving in terms of field of view, illumination profile, resolution, and processing power. We shall present our approach of a camera-based advanced driver assistance systems (ADAS) named BrightEye™, which makes use of the AGIS technology in the automotive field.

  18. Active imaging system with Faraday filter

    DOEpatents

    Snyder, James J.

    1993-01-01

    An active imaging system has a low to medium powered laser transmitter and receiver wherein the receiver includes a Faraday filter with an ultranarrow optical bandpass and a bare (nonintensified) CCD camera. The laser is locked in the vicinity of the passband of the Faraday filter. The system has high sensitivity to the laser illumination while eliminating solar background.

  19. Active imaging system with Faraday filter

    DOEpatents

    Snyder, J.J.

    1993-04-13

    An active imaging system has a low to medium powered laser transmitter and receiver wherein the receiver includes a Faraday filter with an ultranarrow optical bandpass and a bare (nonintensified) CCD camera. The laser is locked in the vicinity of the passband of the Faraday filter. The system has high sensitivity to the laser illumination while eliminating solar background.

  20. Brain bases for auditory stimulus-driven figure-ground segregation.

    PubMed

    Teki, Sundeep; Chait, Maria; Kumar, Sukhbinder; von Kriegstein, Katharina; Griffiths, Timothy D

    2011-01-05

    Auditory figure-ground segregation, listeners' ability to selectively hear out a sound of interest from a background of competing sounds, is a fundamental aspect of scene analysis. In contrast to the disordered acoustic environment we experience during everyday listening, most studies of auditory segregation have used relatively simple, temporally regular signals. We developed a new figure-ground stimulus that incorporates stochastic variation of the figure and background that captures the rich spectrotemporal complexity of natural acoustic scenes. Figure and background signals overlap in spectrotemporal space, but vary in the statistics of fluctuation, such that the only way to extract the figure is by integrating the patterns over time and frequency. Our behavioral results demonstrate that human listeners are remarkably sensitive to the appearance of such figures. In a functional magnetic resonance imaging experiment, aimed at investigating preattentive, stimulus-driven, auditory segregation mechanisms, naive subjects listened to these stimuli while performing an irrelevant task. Results demonstrate significant activations in the intraparietal sulcus (IPS) and the superior temporal sulcus related to bottom-up, stimulus-driven figure-ground decomposition. We did not observe any significant activation in the primary auditory cortex. Our results support a role for automatic, bottom-up mechanisms in the IPS in mediating stimulus-driven, auditory figure-ground segregation, which is consistent with accumulating evidence implicating the IPS in structuring sensory input and perceptual organization.

  1. Figurative Language Awards Ceremony.

    ERIC Educational Resources Information Center

    Fink, Lisa

    Figurative language enlivens a text, providing visuals in the minds of readers. This lesson will have students listening to and reading selected texts as they seek out their favorite literary devices. During the five to seven 50-minute sessions, grade three through five students will: acquire a clear understanding of the concept of figurative…

  2. OECD in Figures, 2008

    ERIC Educational Resources Information Center

    OECD Publishing (NJ1), 2008

    2008-01-01

    "OECD in Figures" is a primary statistical source for key data on OECD countries, ranging from economic growth and employment to inflation, trade and environment. Information is presented in tabular form for: (1) Demography and Health; (2) Economy; (3) Energy; (4) Labour; (5) Science and Technology; (6) Environment; (7) Education; (8)…

  3. Changes in Brain Activation Associated with Spontaneous Improvization and Figural Creativity After Design-Thinking-Based Training: A Longitudinal fMRI Study.

    PubMed

    Saggar, Manish; Quintin, Eve-Marie; Bott, Nicholas T; Kienitz, Eliza; Chien, Yin-Hsuan; Hong, Daniel W-C; Liu, Ning; Royalty, Adam; Hawthorne, Grace; Reiss, Allan L

    2016-06-15

    Creativity is widely recognized as an essential skill for entrepreneurial success and adaptation to daily-life demands. However, we know little about the neural changes associated with creative capacity enhancement. For the first time, using a prospective, randomized control design, we examined longitudinal changes in brain activity associated with participating in a five-week design-thinking-based Creative Capacity Building Program (CCBP), when compared with Language Capacity Building Program (LCBP). Creativity, an elusive and multifaceted construct, is loosely defined as an ability to produce useful/appropriate and novel outcomes. Here, we focus on one of the facets of creative thinking-spontaneous improvization. Participants were assessed pre- and post-intervention for spontaneous improvization skills using a game-like figural Pictionary-based fMRI task. Whole-brain group-by-time interaction revealed reduced task-related activity in CCBP participants (compared with LCBP participants) after training in the right dorsolateral prefrontal cortex, anterior/paracingulate gyrus, supplementary motor area, and parietal regions. Further, greater cerebellar-cerebral connectivity was observed in CCBP participants at post-intervention when compared with LCBP participants. In sum, our results suggest that improvization-based creative capacity enhancement is associated with reduced engagement of executive functioning regions and increased involvement of spontaneous implicit processing.

  4. Figural symbolism in Chinese ideographs.

    PubMed

    Koriat, A; Levy, I

    1979-07-01

    Hebrew-speaking subjects were presented with 42 pairs of Chinese characters designating antonymic concepts and were required to match them with their corresponding Hebrew words. Correct translation was significant and was related to foreign language study and academic experience. Highest success was found for the activity domain of the semantic differential and for attributes judged to afford a diagrammatic representation. Examination of the character-referent relationships suggested that translation success was due to principles of figural symbolism rather than to pictographic representation of the attributes in question. The results are seen as suggestive of the effects of figural symbolization on the invention and/or evolution of natural scripts and are discussed in terms of the manner in which the graphic medium has been fashioned to convey abstract concepts.

  5. Active Mask Segmentation of Fluorescence Microscope Images

    PubMed Central

    Srinivasa, Gowri; Fickus, Matthew C.; Guo, Yusong; Linstedt, Adam D.; Kovačević, Jelena

    2009-01-01

    We propose a new active mask algorithm for the segmentation of fluorescence microscope images of punctate patterns. It combines the (a) flexibility offered by active-contour methods, (b) speed offered by multiresolution methods, (c) smoothing offered by multiscale methods, and (d) statistical modeling offered by region-growing methods into a fast and accurate segmentation tool. The framework moves from the idea of the “contour” to that of “inside and outside”, or, masks, allowing for easy multidimensional segmentation. It adapts to the topology of the image through the use of multiple masks. The algorithm is almost invariant under initialization, allowing for random initialization, and uses a few easily tunable parameters. Experiments show that the active mask algorithm matches the ground truth well, and outperforms the algorithm widely used in fluorescence microscopy, seeded watershed, both qualitatively as well as quantitatively. PMID:19380268

  6. Active gated imaging for automotive safety applications

    NASA Astrophysics Data System (ADS)

    Grauer, Yoav; Sonn, Ezri

    2015-03-01

    The paper presents the Active Gated Imaging System (AGIS), in relation to the automotive field. AGIS is based on a fast gated-camera equipped with a unique Gated-CMOS sensor, and a pulsed Illuminator, synchronized in the time domain to record images of a certain range of interest which are then processed by computer vision real-time algorithms. In recent years we have learned the system parameters which are most beneficial to night-time driving in terms of; field of view, illumination profile, resolution and processing power. AGIS provides also day-time imaging with additional capabilities, which enhances computer vision safety applications. AGIS provides an excellent candidate for camera-based Advanced Driver Assistance Systems (ADAS) and the path for autonomous driving, in the future, based on its outstanding low/high light-level, harsh weather conditions capabilities and 3D potential growth capabilities.

  7. Image Segmentation With Cage Active Contours.

    PubMed

    Garrido, Lluís; Guerrieri, Marité; Igual, Laura

    2015-12-01

    In this paper, we present a framework for image segmentation based on parametrized active contours. The evolving contour is parametrized according to a reduced set of control points that form a closed polygon and have a clear visual interpretation. The parametrization, called mean value coordinates, stems from the techniques used in computer graphics to animate virtual models. Our framework allows to easily formulate region-based energies to segment an image. In particular, we present three different local region-based energy terms: 1) the mean model; 2) the Gaussian model; 3) and the histogram model. We show the behavior of our method on synthetic and real images and compare the performance with state-of-the-art level set methods.

  8. Bioluminescence imaging of myeloperoxidase activity in vivo

    PubMed Central

    Gross, Shimon; Gammon, Seth T; Moss, Britney L; Rauch, Daniel; Harding, John; Heinecke, Jay W; Ratner, Lee; Piwnica-Worms, David

    2010-01-01

    The myeloperoxidase (MPO) system of activated phagocytes is central to normal host defense mechanisms, and dysregulated MPO contributes to the pathogenesis of inflammatory disease states ranging from atherosclerosis to cancer. Here we show that upon systemic administration, the small molecule luminol enables noninvasive bioluminescence imaging (BLI) of MPO activity in vivo. Luminol-BLI allowed quantitative longitudinal monitoring of MPO activity in animal models of acute dermatitis, mixed allergic contact hypersensitivity, focal arthritis and spontaneous large granular lymphocytic tumors. Bioluminescence colocalized with histological sites of inflammation and was totally abolished in gene-deleted Mpo−/− mice, despite massive tissue infiltration of neutrophils and activated eosinophils, indicating that eosinophil peroxidase did not contribute to luminol-BLI in vivo. Thus, luminol-BLI provides a noninvasive, specific and highly sensitive optical readout of phagocyte-mediated MPO activity in vivo and may enable new diagnostic applications in a wide range of acute and chronic inflammatory conditions. PMID:19305414

  9. Bioluminescence imaging of myeloperoxidase activity in vivo.

    PubMed

    Gross, Shimon; Gammon, Seth T; Moss, Britney L; Rauch, Daniel; Harding, John; Heinecke, Jay W; Ratner, Lee; Piwnica-Worms, David

    2009-04-01

    The myeloperoxidase (MPO) system of activated phagocytes is central to normal host defense mechanisms, and dysregulated MPO contributes to the pathogenesis of inflammatory disease states ranging from atherosclerosis to cancer. Here we show that upon systemic administration, the small molecule luminol enables noninvasive bioluminescence imaging (BLI) of MPO activity in vivo. Luminol-BLI allowed quantitative longitudinal monitoring of MPO activity in animal models of acute dermatitis, mixed allergic contact hypersensitivity, focal arthritis and spontaneous large granular lymphocytic tumors. Bioluminescence colocalized with histological sites of inflammation and was totally abolished in gene-deleted Mpo(-/-) mice, despite massive tissue infiltration of neutrophils and activated eosinophils, indicating that eosinophil peroxidase did not contribute to luminol-BLI in vivo. Thus, luminol-BLI provides a noninvasive, specific and highly sensitive optical readout of phagocyte-mediated MPO activity in vivo and may enable new diagnostic applications in a wide range of acute and chronic inflammatory conditions.

  10. A functional magnetic resonance imaging study of the body schema using full human line-drawing figures in an on-line verbal naming and localization task of single body part words.

    PubMed

    McCrea, Simon M

    2007-06-18

    Naming and localization of individual body part words to a high-resolution line drawing of a full human figure was tested in a mixed-sex sample of nine right handed subjects. Activation within the superior medial left parietal cortex and bilateral dorsolateral cortex was consistent with involvement of the body schema which is a dynamic postural self-representation coding and combining sensory afference and motor efference inputs/outputs that is automatic and nonconscious. Additional activation of the left rostral occipitotemporal cortex was consistent with involvement of the neural correlates of the verbalizable body structural description that encodes semantic and categorical representations to animate objects such as full human figures. The results point to a highly distributed cortical representation for the encoding and manipulation of body part information and highlight the need for the incorporation of more ecologically valid measures of body schema coding in future functional neuroimaging studies.

  11. Active imaging system with Faraday filter

    SciTech Connect

    Snyder, J.J.

    1992-12-31

    This invention is comprised of an active imaging system which has a low to medium powered laser transmitter and a receiver wherein the receiver includes a Faraday filter with an ultranarrow optical bandpass and a bare (nonintensified) CCD camera. The laser is locked in the vicinity of the passband of the Faraday filter. The system has high sensitivity to the laser illumination wile eliminating solar background.

  12. Hooke's figurations: a figural drawing attributed to Robert Hooke.

    PubMed

    Hunter, Matthew C

    2010-09-20

    The experimental philosopher Robert Hooke (1635-1703) is known to have apprenticed to the leading painter Peter Lely on his first arrival in London in the late 1640s. Yet the relevance of Hooke's artistic training to his mature draughtsmanship and identity has remained unclear. Shedding light on that larger interpretive problem, this article argues for the attribution to Hooke of a figural drawing now in Tate Britain (T10678). This attributed drawing is especially interesting because it depicts human subjects and bears Hooke's name functioning as an artistic signature, both highly unusual features for his draughtsmanship. From evidence of how this drawing was collected and physically placed alongside images by leading artists in the early eighteenth century, I suggest how it can offer new insight into the reception of Hooke and his graphic work in the early Enlightenment.

  13. Texture Segregation Causes Early Figure Enhancement and Later Ground Suppression in Areas V1 and V4 of Visual Cortex

    PubMed Central

    Poort, Jasper; Self, Matthew W.; van Vugt, Bram; Malkki, Hemi; Roelfsema, Pieter R.

    2016-01-01

    Segregation of images into figures and background is fundamental for visual perception. Cortical neurons respond more strongly to figural image elements than to background elements, but the mechanisms of figure–ground modulation (FGM) are only partially understood. It is unclear whether FGM in early and mid-level visual cortex is caused by an enhanced response to the figure, a suppressed response to the background, or both. We studied neuronal activity in areas V1 and V4 in monkeys performing a texture segregation task. We compared texture-defined figures with homogeneous textures and found an early enhancement of the figure representation, and a later suppression of the background. Across neurons, the strength of figure enhancement was independent of the strength of background suppression. We also examined activity in the different V1 layers. Both figure enhancement and ground suppression were strongest in superficial and deep layers and weaker in layer 4. The current–source density profiles suggested that figure enhancement was caused by stronger synaptic inputs in feedback-recipient layers 1, 2, and 5 and ground suppression by weaker inputs in these layers, suggesting an important role for feedback connections from higher level areas. These results provide new insights into the mechanisms for figure–ground organization. PMID:27522074

  14. Functional Evaluation of Hidden Figures Object Analysis in Children with Autistic Disorder

    ERIC Educational Resources Information Center

    Malisza, Krisztina L.; Clancy, Christine; Shiloff, Deborah; Foreman, Derek; Holden, Jeanette; Jones, Cheryl; Paulson, K.; Summers, Randy; Yu, C. T.; Chudley, Albert E.

    2011-01-01

    Functional magnetic resonance imaging (fMRI) during performance of a hidden figures task (HFT) was used to compare differences in brain function in children diagnosed with autism disorder (AD) compared to children with attention-deficit/hyperactivity disorder (ADHD) and typical controls (TC). Overall greater functional MRI activity was observed in…

  15. PSMA-Activated Imaging Agents for Prostate Cancer

    DTIC Science & Technology

    2009-07-01

    media and the cell extract were run on the LCMS . Figure 3. MTT assay evaluating varying concentrations of I-PD...Society 62, 2422-2423. 7. Fujii, A., Tanaka, K., Tsuchiya, Y., Cook, E.S., 1971. Antistaphylococcal and Antifibrinolytic Activities of Omega- Amino ... Acids and Their L-Histidine Dipeptides. Journal of Medicinal Chemistry 14, 354-&.

  16. Electromagnetic imaging of dynamic brain activity

    SciTech Connect

    Mosher, J.; Leahy, R. . Dept. of Electrical Engineering); Lewis, P.; Lewine, J.; George, J. ); Singh, M. . Dept. of Radiology)

    1991-01-01

    Neural activity in the brain produces weak dynamic electromagnetic fields that can be measured by an array of sensors. Using a spatio-temporal modeling framework, we have developed a new approach to localization of multiple neural sources. This approach is based on the MUSIC algorithm originally developed for estimating the direction of arrival of signals impinging on a sensor array. We present applications of this technique to magnetic field measurements of a phantom and of a human evoked somatosensory response. The results of the somatosensory localization are mapped onto the brain anatomy obtained from magnetic resonance images.

  17. Electromagnetic imaging of dynamic brain activity

    SciTech Connect

    Mosher, J.; Leahy, R.; Lewis, P.; Lewine, J.; George, J.; Singh, M.

    1991-12-31

    Neural activity in the brain produces weak dynamic electromagnetic fields that can be measured by an array of sensors. Using a spatio-temporal modeling framework, we have developed a new approach to localization of multiple neural sources. This approach is based on the MUSIC algorithm originally developed for estimating the direction of arrival of signals impinging on a sensor array. We present applications of this technique to magnetic field measurements of a phantom and of a human evoked somatosensory response. The results of the somatosensory localization are mapped onto the brain anatomy obtained from magnetic resonance images.

  18. Lunar Regolith Figures of Merit

    NASA Technical Reports Server (NTRS)

    Rickman, Doug; Scjrader. Cjrostoam; Jpe (zer. Jams); Fourroux, Kathy

    2009-01-01

    This viewgraph presentation reviews the lunar regolith figures of merit. The contents include: 1) A quick review of Figures-of-Merit (FoM); 2) Software Implementation of FoM Algorithms; and 3) Demonstration of the Software.

  19. Making better scientific figures

    NASA Astrophysics Data System (ADS)

    Hawkins, Ed; McNeall, Doug

    2016-04-01

    In the words of the UK government chief scientific adviser "Science is not finished until it's communicated" (Walport 2013). The tools to produce good visual communication have never been so easily accessible to scientists as at the present. Correspondingly, it has never been easier to produce and disseminate poor graphics. In this presentation, we highlight some good practice and offer some practical advice in preparing scientific figures for presentation to peers or to the public. We identify common mistakes in visualisation, including some made by the authors, and offer some good reasons not to trust defaults in graphics software. In particular, we discuss the use of colour scales and share our experiences in running a social media campaign (http://tiny.cc/endrainbow) to replace the "rainbow" (also "jet", or "spectral") colour scale as the default in (climate) scientific visualisation.

  20. The Theory of Figural Concepts.

    ERIC Educational Resources Information Center

    Fischbein, Efraim

    1993-01-01

    The main thesis of the paper is that geometry deals with mental entities (the so-called geometrical figures) which possess simultaneously conceptual and figural characters. The paper analyzes the internal tensions which may arise in figural concepts because of their double nature, developmental aspects, and didactical implications. (Author/MDH)

  1. Neural substrates of figurative language during natural speech perception: an fMRI study

    PubMed Central

    Nagels, Arne; Kauschke, Christina; Schrauf, Judith; Whitney, Carin; Straube, Benjamin; Kircher, Tilo

    2013-01-01

    Many figurative expressions are fully conventionalized in everyday speech. Regarding the neural basis of figurative language processing, research has predominantly focused on metaphoric expressions in minimal semantic context. It remains unclear in how far metaphoric expressions during continuous text comprehension activate similar neural networks as isolated metaphors. We therefore investigated the processing of similes (figurative language, e.g., “He smokes like a chimney!”) occurring in a short story. Sixteen healthy, male, native German speakers listened to similes that came about naturally in a short story, while blood-oxygenation-level-dependent (BOLD) responses were measured with functional magnetic resonance imaging (fMRI). For the event-related analysis, similes were contrasted with non-figurative control sentences (CS). The stimuli differed with respect to figurativeness, while they were matched for frequency of words, number of syllables, plausibility, and comprehensibility. Similes contrasted with CS resulted in enhanced BOLD responses in the left inferior (IFG) and adjacent middle frontal gyrus. Concrete CS as compared to similes activated the bilateral middle temporal gyri as well as the right precuneus and the left middle frontal gyrus (LMFG). Activation of the left IFG for similes in a short story is consistent with results on single sentence metaphor processing. The findings strengthen the importance of the left inferior frontal region in the processing of abstract figurative speech during continuous, ecologically-valid speech comprehension; the processing of concrete semantic contents goes along with a down-regulation of bilateral temporal regions. PMID:24065897

  2. Software systems for modeling articulated figures

    NASA Technical Reports Server (NTRS)

    Phillips, Cary B.

    1989-01-01

    Research in computer animation and simulation of human task performance requires sophisticated geometric modeling and user interface tools. The software for a research environment should present the programmer with a powerful but flexible substrate of facilities for displaying and manipulating geometric objects, yet insure that future tools have a consistent and friendly user interface. Jack is a system which provides a flexible and extensible programmer and user interface for displaying and manipulating complex geometric figures, particularly human figures in a 3D working environment. It is a basic software framework for high-performance Silicon Graphics IRIS workstations for modeling and manipulating geometric objects in a general but powerful way. It provides a consistent and user-friendly interface across various applications in computer animation and simulation of human task performance. Currently, Jack provides input and control for applications including lighting specification and image rendering, anthropometric modeling, figure positioning, inverse kinematics, dynamic simulation, and keyframe animation.

  3. Mitotic figure counts are significantly overestimated in resection specimens of invasive breast carcinomas.

    PubMed

    Lehr, Hans-Anton; Rochat, Candice; Schaper, Cornelia; Nobile, Antoine; Shanouda, Sherien; Vijgen, Sandrine; Gauthier, Arnaud; Obermann, Ellen; Leuba, Susana; Schmidt, Marcus; C, Curzio Ruegg; Delaloye, Jean-Francois; Simiantonaki, Nectaria; Schaefer, Stephan C

    2013-03-01

    Several authors have demonstrated an increased number of mitotic figures in breast cancer resection specimen when compared with biopsy material. This has been ascribed to a sampling artifact where biopsies are (i) either too small to allow formal mitotic figure counting or (ii) not necessarily taken form the proliferating tumor periphery. Herein, we propose a different explanation for this phenomenon. Biopsy and resection material of 52 invasive ductal carcinomas was studied. We counted mitotic figures in 10 representative high power fields and quantified MIB-1 immunohistochemistry by visual estimation, counting and image analysis. We found that mitotic figures were elevated by more than three-fold on average in resection specimen over biopsy material from the same tumors (20±6 vs 6±2 mitoses per 10 high power fields, P=0.008), and that this resulted in a relative diminution of post-metaphase figures (anaphase/telophase), which made up 7% of all mitotic figures in biopsies but only 3% in resection specimen (P<0.005). At the same time, the percentages of MIB-1 immunostained tumor cells among total tumor cells were comparable in biopsy and resection material, irrespective of the mode of MIB-1 quantification. Finally, we found no association between the size of the biopsy material and the relative increase of mitotic figures in resection specimen. We propose that the increase in mitotic figures in resection specimen and the significant shift towards metaphase figures is not due to a sampling artifact, but reflects ongoing cell cycle activity in the resected tumor tissue due to fixation delay. The dwindling energy supply will eventually arrest tumor cells in metaphase, where they are readily identified by the diagnostic pathologist. Taken together, we suggest that the rapidly fixed biopsy material better represents true tumor biology and should be privileged as predictive marker of putative response to cytotoxic chemotherapy.

  4. Natural image classification driven by human brain activity

    NASA Astrophysics Data System (ADS)

    Zhang, Dai; Peng, Hanyang; Wang, Jinqiao; Tang, Ming; Xue, Rong; Zuo, Zhentao

    2016-03-01

    Natural image classification has been a hot topic in computer vision and pattern recognition research field. Since the performance of an image classification system can be improved by feature selection, many image feature selection methods have been developed. However, the existing supervised feature selection methods are typically driven by the class label information that are identical for different samples from the same class, ignoring with-in class image variability and therefore degrading the feature selection performance. In this study, we propose a novel feature selection method, driven by human brain activity signals collected using fMRI technique when human subjects were viewing natural images of different categories. The fMRI signals associated with subjects viewing different images encode the human perception of natural images, and therefore may capture image variability within- and cross- categories. We then select image features with the guidance of fMRI signals from brain regions with active response to image viewing. Particularly, bag of words features based on GIST descriptor are extracted from natural images for classification, and a sparse regression base feature selection method is adapted to select image features that can best predict fMRI signals. Finally, a classification model is built on the select image features to classify images without fMRI signals. The validation experiments for classifying images from 4 categories of two subjects have demonstrated that our method could achieve much better classification performance than the classifiers built on image feature selected by traditional feature selection methods.

  5. Image change detection using a SWIR active imaging system

    NASA Astrophysics Data System (ADS)

    Schneider, Armin L.; Monnin, David; Laurenzis, Martin; Christnacher, Frank

    2013-10-01

    We are currently developing a system consisting of a GPS receiver, a three-axis magnetic compass as well as a digital video camera in order to visualize changes occuring along a regularily used itinerary. This is done by comparing actual images with images from the same scene, which have been acquired during a previous measurement. The luminosity of images from two different passages however can be quite different (due to different meteorological conditions). Whereas the global luminosity can be adjusted using non-linear luminosity correction, the treatment of shadows is more di cult. Since meteorological conditions cannot be controlled, we are investigating the possibility of using a Laser Gated Viewing system in the SWIR domain to illuminate the scene. Using appropriate filters for the camera, we are completely independent of natural illumination and in addition, the system can also be used at night.

  6. Active multi-aperture imaging through turbulence

    NASA Astrophysics Data System (ADS)

    Miller, Nicholas J.; Widiker, Jeffrey J.; McManamon, Paul F.; Haus, Joseph W.

    2012-06-01

    We describe our Innovative Multi Aperture Gimbaless Electro-Optical (IMAGE) testbed which uses coherent detection of the complex field reflected off a diffuse target with seven hexagonally arranged apertures. The seven measured optical fields are then phased with a digital optimization algorithm to synthesize a composite image whose angular resolution exceeds that of a single aperture. This same post-detection phasing algorithm also corrects aberrations induced by imperfect optics and a turbulent atmospheric path. We present the coherent imaging sub-aperture design used in the IMAGE array as well as the design of a compact range used to perform scaled tests of the IMAGE array. We present some experimental results of imaging diffuse targets in the compact range with two phase screens which simulates a ~7[Km] propagation path through distributed atmospheric turbulence.

  7. Three-Dimensional Lissajous Figures.

    ERIC Educational Resources Information Center

    D'Mura, John M.

    1989-01-01

    Described is a mechanically driven device for generating three-dimensional harmonic space figures with different frequencies and phase angles on the X, Y, and Z axes. Discussed are apparatus, viewing stereo pairs, equations of motion, and using space figures in classroom. (YP)

  8. Digital image processing and analysis for activated sludge wastewater treatment.

    PubMed

    Khan, Muhammad Burhan; Lee, Xue Yong; Nisar, Humaira; Ng, Choon Aun; Yeap, Kim Ho; Malik, Aamir Saeed

    2015-01-01

    Activated sludge system is generally used in wastewater treatment plants for processing domestic influent. Conventionally the activated sludge wastewater treatment is monitored by measuring physico-chemical parameters like total suspended solids (TSSol), sludge volume index (SVI) and chemical oxygen demand (COD) etc. For the measurement, tests are conducted in the laboratory, which take many hours to give the final measurement. Digital image processing and analysis offers a better alternative not only to monitor and characterize the current state of activated sludge but also to predict the future state. The characterization by image processing and analysis is done by correlating the time evolution of parameters extracted by image analysis of floc and filaments with the physico-chemical parameters. This chapter briefly reviews the activated sludge wastewater treatment; and, procedures of image acquisition, preprocessing, segmentation and analysis in the specific context of activated sludge wastewater treatment. In the latter part additional procedures like z-stacking, image stitching are introduced for wastewater image preprocessing, which are not previously used in the context of activated sludge. Different preprocessing and segmentation techniques are proposed, along with the survey of imaging procedures reported in the literature. Finally the image analysis based morphological parameters and correlation of the parameters with regard to monitoring and prediction of activated sludge are discussed. Hence it is observed that image analysis can play a very useful role in the monitoring of activated sludge wastewater treatment plants.

  9. A Computer Graphics Human Figure Application Of Biostereometrics

    NASA Astrophysics Data System (ADS)

    Fetter, William A.

    1980-07-01

    A study of improved computer graphic representation of the human figure is being conducted under a National Science Foundation grant. Special emphasis is given biostereometrics as a primary data base from which applications requiring a variety of levels of detail may be prepared. For example, a human figure represented by a single point can be very useful in overview plots of a population. A crude ten point figure can be adequate for queuing theory studies and simulated movement of groups. A one hundred point figure can usefully be animated to achieve different overall body activities including male and female figures. A one thousand point figure si-milarly animated, begins to be useful in anthropometrics and kinesiology gross body movements. Extrapolations of this order-of-magnitude approach ultimately should achieve very complex data bases and a program which automatically selects the correct level of detail for the task at hand. See Summary Figure 1.

  10. Echocardiographic image of an active human heart

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Echocardiographic images provide quick, safe images of the heart as it beats. While a state-of-the art echocardiograph unit is part of the Human Research Facility on International Space Station, quick transmission of images and data to Earth is a challenge. NASA is developing techniques to improve the echocardiography available to diagnose sick astronauts as well as study the long-term effects of space travel on their health. Echocardiography uses ultrasound, generated in a sensor head placed against the patient's chest, to produce images of the structure of the heart walls and valves. However, ultrasonic imaging creates an enormous volume of data, up to 220 million bits per second. This can challenge ISS communications as well as Earth-based providers. Compressing data for rapid transmission back to Earth can degrade the quality of the images. Researchers at the Cleveland Clinic Foundation are working with NASA to develop compression techniques that meet imaging standards now used on the Internet and by the medical community, and that ensure that physicians receive quality diagnostic images.

  11. Figure content analysis for improved biomedical article retrieval

    NASA Astrophysics Data System (ADS)

    You, Daekeun; Apostolova, Emilia; Antani, Sameer; Demner-Fushman, Dina; Thoma, George R.

    2009-01-01

    Biomedical images are invaluable in medical education and establishing clinical diagnosis. Clinical decision support (CDS) can be improved by combining biomedical text with automatically annotated images extracted from relevant biomedical publications. In a previous study we reported 76.6% accuracy using supervised machine learning on the feasibility of automatically classifying images by combining figure captions and image content for usefulness in finding clinical evidence. Image content extraction is traditionally applied on entire images or on pre-determined image regions. Figure images articles vary greatly limiting benefit of whole image extraction beyond gross categorization for CDS due to the large variety. However, text annotations and pointers on them indicate regions of interest (ROI) that are then referenced in the caption or discussion in the article text. We have previously reported 72.02% accuracy in text and symbols localization but we failed to take advantage of the referenced image locality. In this work we combine article text analysis and figure image analysis for localizing pointer (arrows, symbols) to extract ROI pointed that can then be used to measure meaningful image content and associate it with the identified biomedical concepts for improved (text and image) content-based retrieval of biomedical articles. Biomedical concepts are identified using National Library of Medicine's Unified Medical Language System (UMLS) Metathesaurus. Our methods report an average precision and recall of 92.3% and 75.3%, respectively on identifying pointing symbols in images from a randomly selected image subset made available through the ImageCLEF 2008 campaign.

  12. Infrared active polarimetric imaging system controlled by image segmentation algorithms: application to decamouflage

    NASA Astrophysics Data System (ADS)

    Vannier, Nicolas; Goudail, François; Plassart, Corentin; Boffety, Matthieu; Feneyrou, Patrick; Leviandier, Luc; Galland, Frédéric; Bertaux, Nicolas

    2016-05-01

    We describe an active polarimetric imager with laser illumination at 1.5 µm that can generate any illumination and analysis polarization state on the Poincar sphere. Thanks to its full polarization agility and to image analysis of the scene with an ultrafast active-contour based segmentation algorithm, it can perform adaptive polarimetric contrast optimization. We demonstrate the capacity of this imager to detect manufactured objects in different types of environments for such applications as decamouflage and hazardous object detection. We compare two imaging modes having different number of polarimetric degrees of freedom and underline the characteristics that a polarimetric imager aimed at this type of applications should possess.

  13. Structure analysis for plane geometry figures

    NASA Astrophysics Data System (ADS)

    Feng, Tianxiao; Lu, Xiaoqing; Liu, Lu; Li, Keqiang; Tang, Zhi

    2013-12-01

    As there are increasing numbers of digital documents for education purpose, we realize that there is not a retrieval application for mathematic plane geometry images. In this paper, we propose a method for retrieving plane geometry figures (PGFs), which often appear in geometry books and digital documents. First, detecting algorithms are applied to detect common basic geometry shapes from a PGF image. Based on all basic shapes, we analyze the structural relationships between two basic shapes and combine some of them to a compound shape to build the PGF descriptor. Afterwards, we apply matching function to retrieve candidate PGF images with ranking. The great contribution of the paper is that we propose a structure analysis method to better describe the spatial relationships in such image composed of many overlapped shapes. Experimental results demonstrate that our analysis method and shape descriptor can obtain good retrieval results with relatively high effectiveness and efficiency.

  14. R-X Modeling Figures

    SciTech Connect

    Goda, Joetta Marie; Miller, Thomas; Grogan, Brandon

    2016-10-26

    This document contains figures that will be included in an ORNL final report that details computational efforts to model an irradiation experiment performed on the Godiva IV critical assembly. This experiment was a collaboration between LANL and ORNL.

  15. Facts and Figures on Pain

    MedlinePlus

    ... Room Position Statements AAPM Facts and Figures on Pain Overview What is Chronic Pain? Incidence of Pain, ... of them. Back to Top What is Chronic Pain? While acute pain is a normal sensation triggered ...

  16. Being active after a heart attack (image)

    MedlinePlus

    ... best activity when you start exercising after a heart attack. Start slowly, and increase the amount of time ... best activity when you start exercising after a heart attack. Start slowly, and increase the amount of time ...

  17. Sport-specific injuries and medical problems of figure skaters.

    PubMed

    Porter, Emily B; Young, Craig C; Niedfeldt, Mark W; Gottschlich, Laura M

    2007-09-01

    Figure skating is becoming increasingly popular as both a recreational and competitive sport. As the number of figure skating participants increases, so will the number of active patients who present to their primary care physician with sport-related injuries and medical problems. Figure skating is a unique sport that continues to evolve and progress with participants partaking in more difficult moves and more rigorous training programs. Common problems in figure skating include acute musculo-skeletal injuries and chronic overuse injuries, which primarily occur in the foot, ankle, knee, leg, hip, and lower back. Figure skaters are also more likely to endure specific medical problems such as exercise-induced bronchospasm and eating disorders. Primary care physicians are able to contribute to their figure skating patient's health by recognition and appropriate treatment of acute injuries and prevention of chronic injuries and other medical problems.

  18. The Utility of Auroral Image-based Activities Metrics

    NASA Technical Reports Server (NTRS)

    Germany, G.; Spann, J.; Deverapalli, C.; Hung, C.-C.

    2004-01-01

    Auroral activity indices such as Hemispheric Power and Auroral Boundary are currently key data products used for space weather predictions and nowcasting. However, these products are necessarily based on limited observations which must be extrapolated to provide global coverage. The advent of routine space-based auroral imaging in the last decade offers the seeming advantage of more detailed measures of auroral activity. Examples of image-derived products include energy deposition maps, oval location, cap size, and morphological classification. However, activity metrics derived from auroral images have shortcomings, as well. For example, limited fields-of-view and orbital motion prevent full coverage of the auroral regions. This paper will examine the utility of activity metrics derived h m auroral images for operational purposes. The eight-year collection of Polar UVI images databased in the UVI Online Search Tool (OST) will be used to illustrate the advantages and shortcomings of auroral activity metrics. The potential role of other currently-active imaging missions will also be examined and correlative studies to date using auroral imaging will be summarized.

  19. Measurements and analysis of active/passive multispectral imaging

    NASA Astrophysics Data System (ADS)

    Grönwall, Christina; Hamoir, Dominique; Steinvall, Ove; Larsson, Hâkan; Amselem, Elias; Lutzmann, Peter; Repasi, Endre; Göhler, Benjamin; Barbé, Stéphane; Vaudelin, Olivier; Fracès, Michel; Tanguy, Bernard; Thouin, Emmanuelle

    2013-10-01

    This paper describes a data collection on passive and active imaging and the preliminary analysis. It is part of an ongoing work on active and passive imaging for target identification using different wavelength bands. We focus on data collection at NIR-SWIR wavelengths but we also include the visible and the thermal region. Active imaging in NIRSWIR will support the passive imaging by eliminating shadows during day-time and allow night operation. Among the applications that are most likely for active multispectral imaging, we focus on long range human target identification. We also study the combination of active and passive sensing. The target scenarios of interest include persons carrying different objects and their associated activities. We investigated laser imaging for target detection and classification up to 1 km assuming that another cueing sensor - passive EO and/or radar - is available for target acquisition and detection. Broadband or multispectral operation will reduce the effects of target speckle and atmospheric turbulence. Longer wavelengths will improve performance in low visibility conditions due to haze, clouds and fog. We are currently performing indoor and outdoor tests to further investigate the target/background phenomena that are emphasized in these wavelengths. We also investigate how these effects can be used for target identification and image fusion. Performed field tests and the results of preliminary data analysis are reported.

  20. Data Behind the Figures in AAS Journals

    NASA Astrophysics Data System (ADS)

    Biemesderfer, Chris

    2013-01-01

    Substantial amounts of digital data are produced in the scientific enterprise, and much of it is carefully analyzed and processed. Often resulting from a good deal of intellectual effort, many of these highly-processed products are published in the scholarly literature. Many of these data - or more precisely, representations of these data - are committed to the scholarly record in the forms of figures and tables that appear within articles: the AAS journals publish more than 30,000 figures and nearly 10,000 tables each year. For more than a decade, the AAS journals have accepted machine-readable tables that provide the data behind (some of) the tables, and recently the journals have started to encourage the submission of the data behind figures. (See the related poster by Greg Schwarz.) During this time, the journals have been refining techniques for acquiring and managing the digital data that underlie figures and tables. In 2012 the AAS was awarded a grant by the US NSF so that the journals can extend the methods for providing access to these data objects, through a deeper collaboration with the VO and with organizations like DataCite, and by spearheading discussions about the formats and metadata that will best facilitate long-term data management and access. An important component of these activities is educating scientists about the importance and benefits of making such data sets available.

  1. Joint contrast optimization and object segmentation in active polarimetric images.

    PubMed

    Anna, Guillaume; Bertaux, Nicolas; Galland, Frédéric; Goudail, François; Dolfi, Daniel

    2012-08-15

    We present a method for automatic target detection based on the iterative interplay between an active polarimetric imager with adaptive capabilities and a snake-based image segmentation algorithm. It successfully addresses the difficult situations where the target and the background differ only by their polarimetric properties. This method illustrates the benefits of integrating digital processing algorithms at the heart of the image acquisition process rather than using them only for postprocessing.

  2. Active terahertz wave imaging system for detecting hidden objects

    NASA Astrophysics Data System (ADS)

    Gan, Yuner; Liu, Ming; Zhao, Yuejin

    2016-11-01

    Terahertz wave can penetrate the common dielectric materials such as clothing, cardboard boxes, plastics and so on. Besides, the low photon energy and non-ionizing characteristic of the terahertz wave are especially suitable for the safety inspection of the human body. Terahertz imaging technology has a tremendous potential in the field of security inspection such as stations, airports and other public places. Terahertz wave imaging systems are divided into two categories: active terahertz imaging systems and passive terahertz imaging systems. So far, most terahertz imaging systems work at point to point mechanical scan pattern with the method of passive imaging. The imaging results of passive imaging tend to have low contrast and the image is not clear enough. This paper designs and implements an active terahertz wave imaging system combining terahertz wave transmitting and receiving with a Cassegrain antenna. The terahertz wave at the frequency of 94GHz is created by impact ionization avalanche transit time (IMPATT) diode, focused on the feed element for Cassegrain antenna by high density polyethylene (HDPE) lens, and transmitted to the human body by Cassegrain antenna. The reflected terahertz wave goes the same way it was emitted back to the feed element for Cassegrain antenna, focused on the horn antenna of detector by another high density polyethylene lens. The scanning method is the use of two-dimensional planar mirror, one responsible for horizontal scanning, and another responsible for vertical scanning. Our system can achieve a clear human body image, has better sensitivity and resolution than passive imaging system, and costs much lower than other active imaging system in the meantime.

  3. Circularly polarized antennas for active holographic imaging through barriers

    SciTech Connect

    McMakin, Douglas L; Severtsen, Ronald H; Lechelt, Wayne M; Prince, James M

    2011-07-26

    Circularly-polarized antennas and their methods of use for active holographic imaging through barriers. The antennas are dielectrically loaded to optimally match the dielectric constant of the barrier through which images are to be produced. The dielectric loading helps to remove barrier-front surface reflections and to couple electromagnetic energy into the barrier.

  4. Active Metamaterials for Terahertz Communication and Imaging

    NASA Astrophysics Data System (ADS)

    Rout, Saroj

    In recent years there has been significant interest in terahertz (THz) systems mostly due to their unique applications in communication and imaging. One of the primary reason for this resurgence is the use of metamaterials to design THz devices due to lack of natural materials that can respond to this electromagnetic spectrum, the so-called ''THz gap''. Even after years of intense research, THz systems are complex and expensive, unsuitable for mainstream applications. This work focuses on bridging this gap by building all solid-state THz devices for imaging and communication applications in a commercial integrated circuit (IC) technology. One such canonical device is a THz wave modulator that can be used in THz wireless communication devices and as spatial light modulator (SLM) for THz imaging systems. The key contribution of this thesis is a metamaterial based THz wave modulator fabricated in a commercial gallium arsenide (GaAs) process resonant at 0.46 THz using a novel approach of embedding pseudomorphic high electron mobility transistors (pHEMTs) in metamaterial and demonstrate modulation values over 30%, and THz modulation at frequencies up to 10 MHz. Using the THz wave modulator, we fabricated and experimentally demonstrated an all solid-state metamaterial based THz spatial light modulator (SLM) as a 2x2 pixel array operating around 0.46 THz, by raster scanning an occluded metal object in polystyrene using a single-pixel imaging setup. This was an important step towards building an low-voltage (1V), low power, on-chip integrable THz imaging device. Using the characterization result from the THz SLM, we computationally demonstrated a multi-level amplitude shift keying (ASK) terahertz wireless communication system using spatial light modulation instead of traditional voltage mode modulation, achieving higher spectral efficiency for high speed communication. We show two orders of magnitude improvement in symbol error rate (SER) for a degradation of 20 dB in

  5. Using Digital Imaging in Classroom and Outdoor Activities.

    ERIC Educational Resources Information Center

    Thomasson, Joseph R.

    2002-01-01

    Explains how to use digital cameras and related basic equipment during indoor and outdoor activities. Uses digital imaging in general botany class to identify unknown fungus samples. Explains how to select a digital camera and other necessary equipment. (YDS)

  6. Figure-Ground Segmentation Using Factor Graphs.

    PubMed

    Shen, Huiying; Coughlan, James; Ivanchenko, Volodymyr

    2009-06-04

    Foreground-background segmentation has recently been applied [26,12] to the detection and segmentation of specific objects or structures of interest from the background as an efficient alternative to techniques such as deformable templates [27]. We introduce a graphical model (i.e. Markov random field)-based formulation of structure-specific figure-ground segmentation based on simple geometric features extracted from an image, such as local configurations of linear features, that are characteristic of the desired figure structure. Our formulation is novel in that it is based on factor graphs, which are graphical models that encode interactions among arbitrary numbers of random variables. The ability of factor graphs to express interactions higher than pairwise order (the highest order encountered in most graphical models used in computer vision) is useful for modeling a variety of pattern recognition problems. In particular, we show how this property makes factor graphs a natural framework for performing grouping and segmentation, and demonstrate that the factor graph framework emerges naturally from a simple maximum entropy model of figure-ground segmentation.We cast our approach in a learning framework, in which the contributions of multiple grouping cues are learned from training data, and apply our framework to the problem of finding printed text in natural scenes. Experimental results are described, including a performance analysis that demonstrates the feasibility of the approach.

  7. Ambiguous Benefits: The Effect of Bilingualism on Reversing Ambiguous Figures

    ERIC Educational Resources Information Center

    Bialystok, Ellen; Shapero, Dana

    2005-01-01

    Two studies are reported in which monolingual and bilingual children, approximately 6 years old, attempted to identify the alternative image in a reversible figure. In both studies, bilingual children were more successful than monolinguals in seeing the other meaning in the images. In the first study, there was no relation between the ability to…

  8. Figure/Ground Anomalies in Commercial Television: A Diagnostic Study.

    ERIC Educational Resources Information Center

    Metallinos, Nikos

    A diagnostic study tested the hypothesis that still advertising pictures and television commercials are governed by a basic visual communication principle: that viewers' comprehension and retention of still and moving images depends greatly on the harmonious coexistence of their figure/ground relationships. Ten still images (half in black and…

  9. African American Men’s Perspectives on Promoting Physical Activity: “We’re Not That Difficult to Figure out!”

    PubMed Central

    Friedman, Daniela B.; Hooker, Steven P.; Wilcox, Sara; Burroughs, Ericka L.; Rheaume, Carol E.

    2012-01-01

    African American men report poorer health than do White men and have significantly greater odds for developing chronic diseases partly because of limited physical activity. Understanding how to encourage healthy behaviors among African American men will be critical in the development of effective physical activity messages and programs. Guided by principles of cultural sensitivity and social marketing, this research examined middle-aged and older African American men’s recommended strategies for promoting physical activity to African American men of their age. The authors report results from. 49 interviews conducted with middle-aged (45–64 years) and older (65–84 years) African American men in South Carolina. Four groups of African American men were recruited; middle-aged active men (n = 17), middle-aged inactive men (n = 12), older active men (n = 10), older inactive men (n = 10). Themes related to marketing and recruitment strategies, message content, and spokesperson characteristics emerged and differed by age and physical activity level. Recommended marketing strategies included word of mouth; use of mass media; partnering with churches, businesses, and fraternities; strategic placement of messages; culturally appropriate message framing; and careful attention to selection of program spokespersons. Findings will help in the marketing, design, implementation, and evaluation of culturally appropriate interventions to encourage physical activity among middle-aged and older African American men in the South. PMID:22808914

  10. Molecular Imaging of the ATM Kinase Activity

    SciTech Connect

    Williams, Terence M.; Nyati, Shyam; Ross, Brian D.; Rehemtulla, Alnawaz

    2013-08-01

    Purpose: Ataxia telangiectasia mutated (ATM) is a serine/threonine kinase critical to the cellular DNA-damage response, including from DNA double-strand breaks. ATM activation results in the initiation of a complex cascade of events including DNA damage repair, cell cycle checkpoint control, and survival. We sought to create a bioluminescent reporter that dynamically and noninvasively measures ATM kinase activity in living cells and subjects. Methods and Materials: Using the split luciferase technology, we constructed a hybrid cDNA, ATM-reporter (ATMR), coding for a protein that quantitatively reports on changes in ATM kinase activity through changes in bioluminescence. Results: Treatment of ATMR-expressing cells with ATM inhibitors resulted in a dose-dependent increase in bioluminescence activity. In contrast, induction of ATM kinase activity upon irradiation resulted in a decrease in reporter activity that correlated with ATM and Chk2 activation by immunoblotting in a time-dependent fashion. Nuclear targeting improved ATMR sensitivity to both ATM inhibitors and radiation, whereas a mutant ATMR (lacking the target phosphorylation site) displayed a muted response. Treatment with ATM inhibitors and small interfering (si)RNA-targeted knockdown of ATM confirm the specificity of the reporter. Using reporter expressing xenografted tumors demonstrated the ability of ATMR to report in ATM activity in mouse models that correlated in a time-dependent fashion with changes in Chk2 activity. Conclusions: We describe the development and validation of a novel, specific, noninvasive bioluminescent reporter that enables monitoring of ATM activity in real time, in vitro and in vivo. Potential applications of this reporter include the identification and development of novel ATM inhibitors or ATM-interacting partners through high-throughput screens and in vivo pharmacokinetic/pharmacodynamic studies of ATM inhibitors in preclinical models.

  11. Concepts and Figures in Geometric Reasoning.

    ERIC Educational Resources Information Center

    Fischbein, Efraim; Nachlieli, Talli

    1998-01-01

    Opens with the theoretical construct of figural concepts. Argues that geometrical figures are characterized by both conceptual and sensorial properties. Investigates the effects of interaction between conceptual and figural components. Contains 19 references. (DDR)

  12. Imaging of Alkaline Phosphatase Activity in Bone Tissue

    PubMed Central

    Gade, Terence P.; Motley, Matthew W.; Beattie, Bradley J.; Bhakta, Roshni; Boskey, Adele L.; Koutcher, Jason A.; Mayer-Kuckuk, Philipp

    2011-01-01

    The purpose of this study was to develop a paradigm for quantitative molecular imaging of bone cell activity. We hypothesized the feasibility of non-invasive imaging of the osteoblast enzyme alkaline phosphatase (ALP) using a small imaging molecule in combination with 19Flourine magnetic resonance spectroscopic imaging (19FMRSI). 6, 8-difluoro-4-methylumbelliferyl phosphate (DiFMUP), a fluorinated ALP substrate that is activatable to a fluorescent hydrolysis product was utilized as a prototype small imaging molecule. The molecular structure of DiFMUP includes two Fluorine atoms adjacent to a phosphate group allowing it and its hydrolysis product to be distinguished using 19Fluorine magnetic resonance spectroscopy (19FMRS) and 19FMRSI. ALP-mediated hydrolysis of DiFMUP was tested on osteoblastic cells and bone tissue, using serial measurements of fluorescence activity. Extracellular activation of DiFMUP on ALP-positive mouse bone precursor cells was observed. Concurringly, DiFMUP was also activated on bone derived from rat tibia. Marked inhibition of the cell and tissue activation of DiFMUP was detected after the addition of the ALP inhibitor levamisole. 19FMRS and 19FMRSI were applied for the non-invasive measurement of DiFMUP hydrolysis. 19FMRS revealed a two-peak spectrum representing DiFMUP with an associated chemical shift for the hydrolysis product. Activation of DiFMUP by ALP yielded a characteristic pharmacokinetic profile, which was quantifiable using non-localized 19FMRS and enabled the development of a pharmacokinetic model of ALP activity. Application of 19FMRSI facilitated anatomically accurate, non-invasive imaging of ALP concentration and activity in rat bone. Thus, 19FMRSI represents a promising approach for the quantitative imaging of bone cell activity during bone formation with potential for both preclinical and clinical applications. PMID:21799916

  13. Statistical algorithms for target detection in coherent active polarimetric images.

    PubMed

    Goudail, F; Réfrégier, P

    2001-12-01

    We address the problem of small-target detection with a polarimetric imager that provides orthogonal state contrast images. Such active systems allow one to measure the degree of polarization of the light backscattered by purely depolarizing isotropic materials. To be independent of the spatial nonuniformities of the illumination beam, small-target detection on the orthogonal state contrast image must be performed without using the image of backscattered intensity. We thus propose and develop a simple and efficient target detection algorithm based on a nonlinear pointwise transformation of the orthogonal state contrast image followed by a maximum-likelihood algorithm optimal for additive Gaussian perturbations. We demonstrate the efficiency of this suboptimal technique in comparison with the optimal one, which, however, assumes a priori knowledge about the scene that is not available in practice. We illustrate the performance of this approach on both simulated and real polarimetric images.

  14. A Radiological Image Processing Facility and some of its Three-Dimensional Data Manipulation Capabilities

    PubMed Central

    Huang, H.K.; Mankovich, Nicholas J.; Chuang, K.S.; Papin, Patrick; Lo, S. B.; Wong, C. K.; Hernandez-Armas, Jose

    1983-01-01

    In anticipation of the arrival of a digital radiology department, a dedicated image processing laboratory has been established within the Department of Radiological Sciences, UCLA. This laboratory consists of a multiple user computer, an image processor, a communication system, and an image mass storage device. Three major areas of activities in the laboratory are the development of a radiological image archiving and communication system, installation of a multiple digital viewing station, and research on picture processing techniques to enhance the image diagnostic value. This paper describes the system configuration of the laboratory and some of its capabilities in manipulating three-dimensional medical images. ImagesFigure 2Figure 3Figure 4

  15. Observations of Io's Active Volcanoes from IRTF: Imaging and Occultation Lightcurves

    NASA Astrophysics Data System (ADS)

    Rathbun, J. A.; Spencer, J. R.

    2014-12-01

    We have been observing Ionian volcanism from NASA's Infrared Telescope Facility (IRTF) for more than two decades. The frequency of our observations increases dramatically when spacecraft are observing Io in order to complement the data returned by the spacecraft. The Japanese Space Agency's (JAXA) Hisaki (Sprint-A) mission recently observd the Jupiter system from earth orbit, monitoring the Io Plasma Torus and Jovian aurora. In order to investigate the possible influence of Io volcanism on the torus, we observed Io's volcanoes from the IRTF in Hawaii between September 2013 and May 2014. We imaged Io at 2.2, 3.5, and 4.8 microns in eclipse and reflected sunlight. We also observed Io during occultation by Jupiter, which allows us to locate and characterize individual volcanic eruptions, with greater spatial accuracy, on the Jupiter-facing hemisphere. The 2013 3.5 micron images of a sunlit Io showed no obvious bright volcanic features. However, further increases in spatial resolution is possible with shift-and-add processing of short exposure images. Preliminary occultation lightcurves from 2013 show moderate levels of activity at Kaneheliki/Janus and Loki, the two volcanic centers most often observed in occultation lightcurves. Loki was much brighter in 2013 than during the New Horizons flyby in 2007, but not as bright as during the Galileo era (see figure). From February 2014 through May 2014, due to a planned upgrade on the SPEX instrument and an unplanned required repair on the NSFCam2 instrument (both of which we have used previously), we exclusively used the CSHELL instrument as an imager. Unfortunately, CSHELL was not designed for imaging and has limited spatial resolution and photometric precision, complicating image analysis.

  16. An Investigation of Implicit Active Contours for Scientific Image Segmentation

    SciTech Connect

    Weeratunga, S K; Kamath, C

    2003-10-29

    The use of partial differential equations in image processing has become an active area of research in the last few years. In particular, active contours are being used for image segmentation, either explicitly as snakes, or implicitly through the level set approach. In this paper, we consider the use of the implicit active contour approach for segmenting scientific images of pollen grains obtained using a scanning electron microscope. Our goal is to better understand the pros and cons of these techniques and to compare them with the traditional approaches such as the Canny and SUSAN edge detectors. The preliminary results of our study show that the level set method is computationally expensive and requires the setting of several different parameters. However, it results in closed contours, which may be useful in separating objects from the background in an image.

  17. Choreography Styles in Figure Skating

    ERIC Educational Resources Information Center

    Moormann, Peter Paul

    2006-01-01

    Fifty-eight figure skating trainers from fifteen different countries acted as volunteers in this study on choreography styles. The styles were based on reports of artistic-creative strategies in composing music, drawing, writing poems or novels, and in making dances. The prevalence of the Mozartian (at the onset the choreographer already has a…

  18. Storytelling Figures: A Pueblo Tradition.

    ERIC Educational Resources Information Center

    Kraus, Nancy

    1997-01-01

    In a collaborative unit on pueblo storytelling figures involving art, music, language arts, and physical education, a teacher describes how she helped second graders understand the Pueblo pottery tradition by reading aloud literature covering the past and present. Lists folklore, fiction, poetry, nonfiction, professional resources, videos, CDs,…

  19. Vortex shedding as a precursor of turbulent electrical activity in cardiac muscle.

    PubMed Central

    Cabo, C; Pertsov, A M; Davidenko, J M; Baxter, W T; Gray, R A; Jalife, J

    1996-01-01

    In cardiac tissue, during partial blockade of the membrane sodium channels, or at high frequencies of excitation, inexcitable obstacles with sharp edges may destabilize the propagation of electrical excitation waves, causing the formation of self-sustained vortices and turbulent cardiac electrical activity. The formation of such vortices, which visually resembles vortex shedding in hydrodynamic turbulent flows, was observed in sheep epicardial tissue using voltage-sensitive dyes in combination with video-imaging techniques. Vortex shedding is a potential mechanism leading to the spontaneous initiation of uncontrolled high-frequency excitation of the heart. Images FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 5 FIGURE 7 PMID:8785270

  20. Theory in Biology: Figure 1 or Figure 7?

    PubMed Central

    2015-01-01

    The pace of modern science is staggering. The quantities of data now flowing from DNA sequencers, fluorescence and electron microscopes, mass spectrometers and other mind-blowing instruments leave us faced with information overload. This explosion in data has brought on its heels a concomitant need for efforts at the kinds of synthesis and unification we see in theoretical physics. Often in cell biology, when theoretical modeling takes place, it is as a figure 7 reflection on experiments that have already been done, with data fitting providing a metric of success. Figure 1 theory, by way of contrast, is about living dangerously by turning our thinking into formal mathematical predictions and confronting that math with experiments that have not yet been done. PMID:26584768

  1. Theory in Biology: Figure 1 or Figure 7?

    PubMed

    Phillips, Rob

    2015-12-01

    The pace of modern science is staggering. The quantities of data now flowing from DNA sequencers, fluorescence and electron microscopes, mass spectrometers, and other mind-blowing instruments leave us faced with information overload. This explosion in data has brought on its heels a concomitant need for efforts at the kinds of synthesis and unification we see in theoretical physics. Often in cell biology, when theoretical modeling takes place, it is as a figure 7 reflection on experiments that have already been done, with data fitting providing a metric of success. Figure 1 theory, by way of contrast, is about living dangerously by turning our thinking into formal mathematical predictions and confronting that math with experiments that have not yet been done.

  2. CMOS Active-Pixel Image Sensor With Simple Floating Gates

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R.; Nakamura, Junichi; Kemeny, Sabrina E.

    1996-01-01

    Experimental complementary metal-oxide/semiconductor (CMOS) active-pixel image sensor integrated circuit features simple floating-gate structure, with metal-oxide/semiconductor field-effect transistor (MOSFET) as active circuit element in each pixel. Provides flexibility of readout modes, no kTC noise, and relatively simple structure suitable for high-density arrays. Features desirable for "smart sensor" applications.

  3. Technologies for imaging neural activity in large volumes

    PubMed Central

    Ji, Na; Freeman, Jeremy; Smith, Spencer L.

    2017-01-01

    Neural circuitry has evolved to form distributed networks that act dynamically across large volumes. Collecting data from individual planes, conventional microscopy cannot sample circuitry across large volumes at the temporal resolution relevant to neural circuit function and behaviors. Here, we review emerging technologies for rapid volume imaging of neural circuitry. We focus on two critical challenges: the inertia of optical systems, which limits image speed, and aberrations, which restrict the image volume. Optical sampling time must be long enough to ensure high-fidelity measurements, but optimized sampling strategies and point spread function engineering can facilitate rapid volume imaging of neural activity within this constraint. We also discuss new computational strategies for the processing and analysis of volume imaging data of increasing size and complexity. Together, optical and computational advances are providing a broader view of neural circuit dynamics, and help elucidate how brain regions work in concert to support behavior. PMID:27571194

  4. IMAGING BRAIN ACTIVATION: SIMPLE PICTURES OF COMPLEX BIOLOGY

    PubMed Central

    Dienel, Gerald A.; Cruz, Nancy F.

    2009-01-01

    Elucidation of biochemical, physiological, and cellular contributions to metabolic images of brain is important for interpretation of images of brain activation and disease. Discordant brain images obtained with [14C]deoxyglucose (DG) and [1- or 6-14C]glucose were previously ascribed to increased glycolysis and rapid [14C]lactate release from tissue, but direct proof of [14C]lactate release from activated brain structures is lacking. Analysis of factors contributing to images of focal metabolic activity evoked by monotonic acoustic stimulation of conscious rats reveals that labeled metabolites of [1- or 6-14C]glucose are quickly released from activated cells due to decarboxylation reactions, spreading via gap junctions, and efflux via lactate transporters. Label release from activated tissue accounts for most of the additional [14C]glucose consumed during activation compared to rest. Metabolism of [3,4-14C]glucose generates about four times more [14C]lactate compared to 14CO2 in extracellular fluid suggesting that most lactate is not locally oxidized. In brain slices, direct assays of lactate uptake from extracellular fluid demonstrate that astrocytes have faster influx and higher transport capacity than neurons. Also, lactate transfer from a single astrocyte to other gap junction-coupled astrocytes exceeds astrocyte-to-neuron lactate shuttling. Astrocytes and neurons have excess capacities for glycolysis, and oxidative metabolism in both cell types rises during sensory stimulation. The energetics of brain activation is quite complex and the proportion of glucose consumed by astrocytes and neurons, lactate generation by either cell type, and the contributions of both cell types to brain images during brain activation are likely to vary with the stimulus paradigm and activated pathways. PMID:19076439

  5. A 190GHz active millimeter-wave imager

    NASA Astrophysics Data System (ADS)

    Brothers, Michael L.; Timms, Greg P.; Bunton, John D.; Archer, John W.; Tello, Juan Y.; Rosolen, Grahame C.; Li, Yue; Hellicar, Andrew D.

    2007-04-01

    The design and testing of a 190 GHz imaging system is presented. The system features two beam-scanning antennas; the first transmits a horizontal fan beam and the second receives a vertical fan beam. By correlating the signals from the antennas, an estimate of the millimeter-wave reflectivity at the intersection of the fan beams is obtained. Each fan beam is scanned by rotating a small subreflector within the antenna; this simple rotation motion allows rapid scanning. The system is portable, currently approximately 0.6m × 0.6m × 2m high; the key size constraint is imposed by the 450 mm aperture length of the antennas. The imager has an angular resolution of 0.25° and a field of view of 14°×14°, resulting in a raw image of approximately 50 × 50 pixels. The raw image is processed using super-resolution techniques. Images will be presented which show the capability of the system to image metallic and ceramic objects beneath clothing. These images were obtained by illuminating the scene with signals from a frequency-doubled Gunn oscillator. While this paper focuses on active imaging, the system can also operate in passive mode with reduced sensitivity.

  6. PET imaging of neurogenic activity in the adult brain: Toward in vivo imaging of human neurogenesis.

    PubMed

    Tamura, Yasuhisa; Kataoka, Yosky

    2017-01-01

    Neural stem cells are present in 2 neurogenic regions, the subventricular zone (SVZ) and the subgranular zone (SGZ) of the hippocampal dentate gyrus (DG), and continue to generate new neurons throughout life. Adult hippocampal neurogenesis is linked to a variety of psychiatric disorders such as depression and anxiety, and to the therapeutic effects of antidepressants, as well as learning and memory. In vivo imaging for hippocampal neurogenic activity may be used to diagnose psychiatric disorders and evaluate the therapeutic efficacy of antidepressants. However, these imaging techniques remain to be established until now. Recently, we established a quantitative positron emission tomography (PET) imaging technique for neurogenic activity in the adult brain with 3'-deoxy-3'-[(18)F]fluoro-L-thymidine ([(18)F]FLT) and probenecid, a drug transporter inhibitor in blood-brain barrier. Moreover, we showed that this PET imaging technique can monitor alterations in neurogenic activity in the hippocampus of adult rats with depression and following treatment with an antidepressant. This PET imaging method may assist in diagnosing depression and in monitoring the therapeutic efficacy of antidepressants. In this commentary, we discuss the possibility of in vivo PET imaging for neurogenic activity in adult non-human primates and humans.

  7. Molecular Imaging of Activated Platelets Allows the Detection of Pulmonary Embolism with Magnetic Resonance Imaging

    PubMed Central

    Heidt, Timo; Ehrismann, Simon; Hövener, Jan-Bernd; Neudorfer, Irene; Hilgendorf, Ingo; Reisert, Marco; Hagemeyer, Christoph E.; Zirlik, Andreas; Reinöhl, Jochen; Bode, Christoph; Peter, Karlheinz; von Elverfeldt, Dominik; von zur Muhlen, Constantin

    2016-01-01

    Early and reliable detection of pulmonary embolism (PE) is critical for improving patient morbidity and mortality. The desire for low-threshold screening for pulmonary embolism is contradicted by unfavorable radiation of currently used computed tomography or nuclear techniques, while standard magnetic resonance imaging still struggles to provide sufficient diagnostic sensitivity in the lung. In this study we evaluate a molecular-targeted contrast agent against activated platelets for non-invasive detection of murine pulmonary thromboembolism using magnetic resonance imaging. By intravenous injection of human thrombin, pulmonary thromboembolism were consistently induced as confirmed by immunohistochemistry of the lung. Magnetic resonance imaging after thrombin injection showed local tissue edema in weighted images which co-localized with the histological presence of pulmonary thromboembolism. Furthermore, injection of a functionalized contrast agent targeting activated platelets provided sensitive evidence of focal accumulation of activated platelets within the edematous area, which, ex vivo, correlated well with the size of the pulmonary embolism. In summary, we here show delivery and specific binding of a functionalized molecular contrast agent against activated platelets for targeting pulmonary thromboembolism. Going forward, molecular imaging may provide new opportunities to increase sensitivity of magnetic resonance imaging for detection of pulmonary embolism. PMID:27138487

  8. Solar Activity Studies using Microwave Imaging Observations

    NASA Technical Reports Server (NTRS)

    Gopalswamy, N.

    2016-01-01

    We report on the status of solar cycle 24 based on polar prominence eruptions (PEs) and microwave brightness enhancement (MBE) information obtained by the Nobeyama radioheliograph. The north polar region of the Sun had near-zero field strength for more than three years (2012-2015) and ended only in September 2015 as indicated by the presence of polar PEs and the lack of MBE. The zero-polar-field condition in the south started only around 2013, but it ended by June 2014. Thus the asymmetry in the times of polarity reversal switched between cycle 23 and 24. The polar MBE is a good proxy for the polar magnetic field strength as indicated by the high degree of correlation between the two. The cross-correlation between the high- and low-latitude MBEs is significant for a lag of approximately 5.5 to 7.3 years, suggesting that the polar field of one cycle indicates the sunspot number of the next cycle in agreement with the Babcock-Leighton mechanism of solar cycles. The extended period of near-zero field in the north-polar region should result in a weak and delayed sunspot activity in the northern hemisphere in cycle 25.

  9. Experiences from long range passive and active imaging

    NASA Astrophysics Data System (ADS)

    Grönwall, Christina; Gustafsson, David; Steinvall, Ove; Tolt, Gustav

    2015-10-01

    We present algorithm evaluations for ATR of small sea vessels. The targets are at km distance from the sensors, which means that the algorithms have to deal with images affected by turbulence and mirage phenomena. We evaluate previously developed algorithms for registration of 3D-generating laser radar data. The evaluations indicate that some robustness to turbulence and mirage induced uncertainties can be handled by our probabilistic-based registration method. We also assess methods for target classification and target recognition on these new 3D data. An algorithm for detecting moving vessels in infrared image sequences is presented; it is based on optical flow estimation. Detection of moving target with an unknown spectral signature in a maritime environment is a challenging problem due to camera motion, background clutter, turbulence and the presence of mirage. First, the optical flow caused by the camera motion is eliminated by estimating the global flow in the image. Second, connected regions containing significant motions that differ from camera motion is extracted. It is assumed that motion caused by a moving vessel is more temporally stable than motion caused by mirage or turbulence. Furthermore, it is assumed that the motion caused by the vessel is more homogenous with respect to both magnitude and orientation, than motion caused by mirage and turbulence. Sufficiently large connected regions with a flow of acceptable magnitude and orientation are considered target regions. The method is evaluated on newly collected sequences of SWIR and MWIR images, with varying targets, target ranges and background clutter. Finally we discuss a concept for combining passive and active imaging in an ATR process. The main steps are passive imaging for target detection, active imaging for target/background segmentation and a fusion of passive and active imaging for target recognition.

  10. Imaging of brain tumor proliferative activity with iodine-131-iododeoxyuridine

    SciTech Connect

    Tjuvajev, J.G.; Macapinlac, H.A.; Daghighian, F.

    1994-09-01

    Iodine-131-iododeoxyuridine (IUdR) uptake and retention was imaged with SPECT at 2 and 24 hr after administering a 10-mCi dose to six patients with primary brain tumors. The SPECT images were directly compared to gadolinium contrast-enhanced MR images as well as to ({sup 18}F) fluorodeoxyglucose (FDG) PET scans and {sup 201}Tl SPECT scans. Localized uptake and retention of IUdR-derived radioactivity was observed in five of six patients. The plasma half-life of ({sup 131}I) IUdR was short (1.5 min) in comparison to the half-life of total plasma radioactivity (6.4 hr). The pattern of ({sup 131}I)IUdR-derived radioactivity was markedly different in the 2-hr compared to 24-hr images. Radioactivity was localized along the periphery of the tumor and extended beyond the margin of tumor identified by contrast enhancement on MRI. The estimated levels of tumor radioactivity at 24 hr, based on semiquantitative phantom studies, ranged between <0.1 and 0.2 {mu}Ci/cc (<0.001% and 0.002% dose/cc); brain levels were not measurable. Iodine-131-IUdR SPECT imaging of brain tumor proliferation has low (marginal) sensitivity due to low count rates and can detect only the most active regions of tumor growth. Imaging at 24 hr represents a washout strategy to reduce {sup 131}I-labeled metabolites contributing to background activity in the tumors, and is more likely to show the pattern of ({sup 131}I)IUdR-DNA incorporation and thereby increase image specificity. Iodine-123-IUdR SPECT imaging at 12 hr and the use of ({sup 124}I)IUdR and PET will improve count acquisitions and image quality. 74 refs., 6 figs., 2 tabs.

  11. Waveforms for Active Sensing: Optical Waveform Design and Analysis for Ballistic Imaging Through Turbid Media

    DTIC Science & Technology

    2008-04-04

    Figure 15 shows the results of two imaging exper- iments where the objective is to read the text written on transparency sheets by a ballpoint pen , sur...λ) + pen (λ)] (3.6) where pen (λ) > 0 is a penalty function that assigns small values to smooth λ and larger values to non-smooth λ. The notion of

  12. Segmentation of volumetric tissue images using constrained active contour models.

    PubMed

    Adiga, P S Umesh

    2003-06-01

    In this article we describe an application of active contour model for the segmentation of 3D histo-pathological images. The 3D images of a thick tissue specimen are obtained as a stack of optical sections using confocal laser beam scanning microscope (CLSM). We have applied noise reduction and feature enhancement methods so that a smooth and slowly varying potential surface is obtained for proper convergence. To increase the capture range of the potential surface, we use a combination of distance potential and the diffused gradient potential as external forces. It has been shown that the region-based information obtained from low-level segmentation can be applied to reduce the adverse influence of the neighbouring nucleus having a strong boundary feature. We have also shown that, by increasing the axial resolution of the image stack, we can automatically propagate the optimum active contour of one image slice to its neighbouring image slices as an appropriate initial model. Results on images of prostate tissue section are presented.

  13. [Electrophysiological mechanisms and possibility of increasing figural creativity under conditions of monetary reward].

    PubMed

    Vol'f, N V; Tarasova, I V

    2012-01-01

    Analysis of EEG correlates of figural creativity (Torrens "Incomplete figures" subtest) and its efficacy after the instruction "to create an original solution" (condition I) and after the same instruction with the promise of a monetary reward for high performance (condition II) was carried out. Fifteen right-handed men and 16 women were examined. In condition II, the image originality was not increased, but performance fluency was reduced as compared to condition I. Promise of the monetary reward in condition II was followed by a decrease in the theta1-rhythm power before the task performance, which persisted during the image creation. Baseline values of the power of rhythms alpha1 and 2 were higher in condition II as compared to condition 1. Promise of the monetary reward in condition II was associated with a reduction of the experimental beta1- and beta2-rhythm power in posterior regions of the cerebral cortex. These effects may be associated with pre-setting to the forthcoming activity and task performance under increased extrinsic motivation. The enhancement of external motivation in condition II also induced changes in hemispheric power asymmetry of the teta1-, alpha1, and beta2-rhythm at the expense of the left-hemisphere activity, which may be the basis of different effects of high motivation levels on subjects, who preferred right or left hemispheric strategies during figural divergent thinking.

  14. Surface figure control for coated optics

    DOEpatents

    Ray-Chaudhuri, Avijit K.; Spence, Paul A.; Kanouff, Michael P.

    2001-01-01

    A pedestal optical substrate that simultaneously provides high substrate dynamic stiffness, provides low surface figure sensitivity to mechanical mounting hardware inputs, and constrains surface figure changes caused by optical coatings to be primarily spherical in nature. The pedestal optical substrate includes a disk-like optic or substrate section having a top surface that is coated, a disk-like base section that provides location at which the substrate can be mounted, and a connecting cylindrical section between the base and optics or substrate sections. The optic section has an optical section thickness.sup.2 /optical section diameter ratio of between about 5 to 10 mm, and a thickness variation between front and back surfaces of less than about 10%. The connecting cylindrical section may be attached via three spaced legs or members. However, the pedestal optical substrate can be manufactured from a solid piece of material to form a monolith, thus avoiding joints between the sections, or the disk-like base can be formed separately and connected to the connecting section. By way of example, the pedestal optical substrate may be utilized in the fabrication of optics for an extreme ultraviolet (EUV) lithography imaging system, or in any optical system requiring coated optics and substrates with reduced sensitivity to mechanical mounts.

  15. Active Contours for Multispectral Images With Non-Homogeneous Sub-Regions

    DTIC Science & Technology

    2005-09-16

    green , and blue. Hyperspectral images, used in remote sensing, are other examples of multispectral im- ages. A set of images, measured by physically...method 1, (b) method 2, (c) proposed method The green solid line of all three graphs presents the same statistics measured within class 2 in the...segmentation result. As the green solid line exists closer to the blue solid line, it presents better result. In figure 8.7(a), the dotted green line with

  16. Non-Invasive Molecular Imaging of Disease Activity in Atherosclerosis

    PubMed Central

    Dweck, Marc R; Aikawa, Elena; Newby, David E; Tarkin, Jason; Rudd, James; Narula, Jagat; Fayad, Zahi A.

    2016-01-01

    Major focus has been placed on the identification of vulnerable plaques as a means of improving the prediction of myocardial infarction. However, this strategy has recently been questioned on the basis that the majority of these individual coronary lesions do not in fact go on to cause clinical events. Attention is therefore shifting to alternative imaging modalities that might provide a more complete pan-coronary assessment of the atherosclerotic disease process. These include markers of disease activity with the potential to discriminate between patients with stable burnt-out disease that is no longer metabolically active and those with active atheroma, faster disease progression and increased risk of infarction. This review will examine how novel molecular imaging approaches can provide such assessments, focusing on inflammation and microcalcification activity, the importance of these processes to coronary atherosclerosis and the advantages and challenges posed by these techniques. PMID:27390335

  17. A novel approach to image neural activity directly by MRI

    NASA Astrophysics Data System (ADS)

    Singh, Manbir; Sungkarat, Witaya

    2005-04-01

    Though an approach to image the electrical activity of neurons directly by detecting phase shifts in MRI was first reported in 1991, results to-date remain equivocal due to the low signal-to-noise ratio. The objective of this work was to develop a stimulus-presentation and data acquisition strategy specially geared to detect phase-dispersion effects of neuronal currents within 10-100 ms following stimulation. The key feature is to set the repeated MR data acquisition time TR and the stimulus presentation interval (TI) slightly different from each other so that the time at which images are acquired shifts gradually from one acquisition to the next with respect to stimulus onset. For example, at TR=275ms and 4 Hz stimulus presentation (TI=250ms), initial synchronization of the stimulus onset and MR acquisition would result in the first image being acquired at a latency of 0+/- (temporal width of data acquisition window), second image at a latency of 25ms, third image at a latency of 50ms and so on up to a latency of 250ms, at which time the stimulus and data acquisition times would become re-synchronized to once again acquire an image at latency=0. Human data were acquired on a 1.5T GE EXCITE scanner from two 8mm thick contiguous slices bracketing the calcarine fissure during a checkerboard flashing at 4 Hz. Preliminary results show activity in the visual cortex at latencies consistent with EEG studies, suggesting the potential of this methodology to image neural activity directly.

  18. Active illuminated space object imaging and tracking simulation

    NASA Astrophysics Data System (ADS)

    Yue, Yufang; Xie, Xiaogang; Luo, Wen; Zhang, Feizhou; An, Jianzhu

    2016-10-01

    Optical earth imaging simulation of a space target in orbit and it's extraction in laser illumination condition were discussed. Based on the orbit and corresponding attitude of a satellite, its 3D imaging rendering was built. General simulation platform was researched, which was adaptive to variable 3D satellite models and relative position relationships between satellite and earth detector system. Unified parallel projection technology was proposed in this paper. Furthermore, we denoted that random optical distribution in laser-illuminated condition was a challenge for object discrimination. Great randomicity of laser active illuminating speckles was the primary factor. The conjunction effects of multi-frame accumulation process and some tracking methods such as Meanshift tracking, contour poid, and filter deconvolution were simulated. Comparison of results illustrates that the union of multi-frame accumulation and contour poid was recommendable for laser active illuminated images, which had capacities of high tracking precise and stability for multiple object attitudes.

  19. Linear and non-linear fluorescence imaging of neuronal activity

    NASA Astrophysics Data System (ADS)

    Fisher, Jonathan A. N.

    Optical imaging of neuronal activity offers new possibilities for understanding brain physiology. The predominant methods in neuroscience for measuring electrical activity require electrodes inserted into the tissue. Such methods, however, provide limited spatial information and are invasive. Optical methods are less physically invasive and offer the possibility for simultaneously imaging the activity of many neurons. In this thesis one- and two-photon fluorescence microscopy techniques were applied to several in vivo and in vitro mammalian preparations. Using one-photon absorption fluorescence microscopy and gradient index (GRIN) lens optics, cortical electrical activity in response to electric stimulation was resolved in three-dimensions at high-speed in the primary somatosensory cortex of the mouse in vivo using voltage-sensitive dyes. Imaging at depths up to 150 mum below the cortex surface, it was possible to resolve depth-dependent patterns of neuronal activity in response to cortical and thalamic electric stimulation. The patterns of activity were consistent with known cortical cellular architecture. In a qualitatively different set of experiments, one-photon fluorescence microscopy via voltage-sensitive dyes was successfully employed to image an in vitro preparation of the perfused rat brainstem during the process of respiratory rhythmogenesis. Imaging results yielded insights into the spatial organization of the central respiratory rhythm generation region in the ventrolateral medulla. A multifocal two-photon scanning microscope was constructed, and design and operation principles are described. Utilizing the novel device, anatomical and functional two-photon imaging via potentiometric dyes and calcium dyes is described, and the results of in vivo versus in vitro imaging are compared. Anatomical imaging results used either functional probe background fluorescence or green fluorescent protein (GFP) expression. Spectroscopic experiments measuring the two

  20. Ultrasound Activated Contrast Imaging for Prostate Cancer Detection

    DTIC Science & Technology

    2005-03-01

    ultrasound engine with a P4-2 phased array transducer were modified to perform EEI on a vector-by-vector basis in fundamental and pulse inversion harmonic...albumin-encapsulated Abunex® bubble is 18 times greater than that for a free bubble if the two bubbles oscillate with the same relative amplitude at...utilizes two acoustic fields: the activation field for intermittently activating contrast bubbles and the imaging field, applied shortly afterwards, for

  1. An active contour model for medical image segmentation with application to brain CT image

    PubMed Central

    Qian, Xiaohua; Wang, Jiahui; Guo, Shuxu; Li, Qiang

    2013-01-01

    Purpose: Cerebrospinal fluid (CSF) segmentation in computed tomography (CT) is a key step in computer-aided detection (CAD) of acute ischemic stroke. Because of image noise, low contrast and intensity inhomogeneity, CSF segmentation has been a challenging task. A region-based active contour model, which is insensitive to contour initialization and robust to intensity inhomogeneity, was developed for segmenting CSF in brain CT images. Methods: The energy function of the region-based active contour model is composed of a range domain kernel function, a space domain kernel function, and an edge indicator function. By minimizing the energy function, the region of edge elements of the target could be automatically identified in images with less dependence on initial contours. The energy function was optimized by means of the deepest descent method with a level set framework. An overlap rate between segmentation results and the reference standard was used to assess the segmentation accuracy. The authors evaluated the performance of the proposed method on both synthetic data and real brain CT images. They also compared the performance level of our method to those of region-scalable fitting (RSF) and global convex segment (GCS) models. Results: For the experiment of CSF segmentation in 67 brain CT images, their method achieved an average overlap rate of 66% compared to the average overlap rates of 16% and 46% from the RSF model and the GCS model, respectively. Conclusions: Their region-based active contour model has the ability to achieve accurate segmentation results in images with high noise level and intensity inhomogeneity. Therefore, their method has great potential in the segmentation of medical images and would be useful for developing CAD schemes for acute ischemic stroke in brain CT images. PMID:23387759

  2. Research on range-gated laser active imaging seeker

    NASA Astrophysics Data System (ADS)

    You, Mu; Wang, PengHui; Tan, DongJie

    2013-09-01

    Compared with other imaging methods such as millimeter wave imaging, infrared imaging and visible light imaging, laser imaging provides both a 2-D array of reflected intensity data as well as 2-D array of range data, which is the most important data for use in autonomous target acquisition .In terms of application, it can be widely used in military fields such as radar, guidance and fuse. In this paper, we present a laser active imaging seeker system based on range-gated laser transmitter and sensor technology .The seeker system presented here consist of two important part, one is laser image system, which uses a negative lens to diverge the light from a pulse laser to flood illuminate a target, return light is collected by a camera lens, each laser pulse triggers the camera delay and shutter. The other is stabilization gimbals, which is designed to be a rotatable structure both in azimuth and elevation angles. The laser image system consists of transmitter and receiver. The transmitter is based on diode pumped solid-state lasers that are passively Q-switched at 532nm wavelength. A visible wavelength was chosen because the receiver uses a Gen III image intensifier tube with a spectral sensitivity limited to wavelengths less than 900nm.The receiver is image intensifier tube's micro channel plate coupled into high sensitivity charge coupled device camera. The image has been taken at range over one kilometer and can be taken at much longer range in better weather. Image frame frequency can be changed according to requirement of guidance with modifiable range gate, The instantaneous field of views of the system was found to be 2×2 deg. Since completion of system integration, the seeker system has gone through a series of tests both in the lab and in the outdoor field. Two different kinds of buildings have been chosen as target, which is located at range from 200m up to 1000m.To simulate dynamic process of range change between missile and target, the seeker system has

  3. Active spectral imaging for standoff detection of explosives

    SciTech Connect

    Skvortsov, L A

    2011-12-31

    Laser methods of standoff detection of explosive traces on surfaces of objects are considered. These methods are based on active formation of multi- and hyperspectral images of an object examined. The possibilities of these methods and the prospects of their development are discussed. Emphasis is laid on the justification of the most preferred field of application of the technique under consideration.

  4. Browsing Image Collections with Representations of Common-Sense Activities.

    ERIC Educational Resources Information Center

    Gordon, Andrew S.

    2001-01-01

    Describes a methodology for creating networks of subject terms by manually representing a large number of common-sense activities that are broadly related to image subject terms. Application of this methodology to the Library of Congress Thesaurus for Graphic Materials produced 768 representations that supported users of a prototype browsing-based…

  5. Evidence for a left-over-right inhibitory mechanism during figural creative thinking in healthy nonartists.

    PubMed

    Huang, Peiyu; Qiu, Lihua; Shen, Lin; Zhang, Yong; Song, Zhe; Qi, Zhiguo; Gong, Qiyong; Xie, Peng

    2013-10-01

    As a complex mental process, creativity requires the coordination of multiple brain regions. Previous pathological research on figural creativity has indicated that there is a mechanism by which the left side of the brain inhibits the activities of the right side of the brain during figural creative thinking, but this mechanism has not been directly demonstrated. In this study, we used functional magnetic resonance imaging (fMRI) to demonstrate the existence of this inhibitory mechanism in young adults (15 women, 11 men, mean age: 22 years) that were not artists. By making comparisons between brain activity during creative and uncreative tasks, we found increased activity in the left middle and inferior frontal lobe and strong decreases in activity in the right middle frontal lobe and the left inferior parietal lobe. As such, these data suggest that the left frontal lobe may inhibit the right hemisphere during figural creative thinking in normal people. Moreover, removal of this inhibition by practicing artistry or through specific damage to the left frontal lobe may facilitate the emergence of artistic creativity.

  6. Trinocular stereovision using figural continuity, dealing with curved objects

    NASA Technical Reports Server (NTRS)

    Vaillant, R.; Faugeras, O. D.

    1989-01-01

    A method to build a dense and reliable 3-D description of a scene from three digital images by means of passive stereovision is presented. This method uses figural continuity to improve the results of a previously developed algorithm. In particular, it copes much better with curved objects and produces results which are organized as 3-D chains of segments.

  7. Relationships of the Piagetian Cognitive Development to Human Figure Drawing.

    ERIC Educational Resources Information Center

    Sisto, Fermino Fernandes

    2000-01-01

    Examined validity of use of human figure drawing to evaluate cognitive development status using Piagetian tasks with 7- to 11-year-olds. Found that scores for children's drawings of a man and a woman correlated significantly with mental imaging, conservation of mass, and conservation of length, suggesting the possibility of finding patterns to…

  8. AMISS - Active and passive MIcrowaves for Security and Subsurface imaging

    NASA Astrophysics Data System (ADS)

    Soldovieri, Francesco; Slob, Evert; Turk, Ahmet Serdar; Crocco, Lorenzo; Catapano, Ilaria; Di Matteo, Francesca

    2013-04-01

    The FP7-IRSES project AMISS - Active and passive MIcrowaves for Security and Subsurface imaging is based on a well-combined network among research institutions of EU, Associate and Third Countries (National Research Council of Italy - Italy, Technische Universiteit Delft - The Netherlands, Yildiz Technical University - Turkey, Bauman Moscow State Technical University - Russia, Usikov Institute for Radio-physics and Electronics and State Research Centre of Superconductive Radioelectronics "Iceberg" - Ukraine and University of Sao Paulo - Brazil) with the aims of achieving scientific advances in the framework of microwave and millimeter imaging systems and techniques for security and safety social issues. In particular, the involved partners are leaders in the scientific areas of passive and active imaging and are sharing their complementary knowledge to address two main research lines. The first one regards the design, characterization and performance evaluation of new passive and active microwave devices, sensors and measurement set-ups able to mitigate clutter and increase information content. The second line faces the requirements to make State-of-the-Art processing tools compliant with the instrumentations developed in the first line, suitable to work in electromagnetically complex scenarios and able to exploit the unexplored possibilities offered by new instrumentations. The main goals of the project are: 1) Development/improvement and characterization of new sensors and systems for active and passive microwave imaging; 2) Set up, analysis and validation of state of art/novel data processing approach for GPR in critical infrastructure and subsurface imaging; 3) Integration of state of art and novel imaging hardware and characterization approaches to tackle realistic situations in security, safety and subsurface prospecting applications; 4) Development and feasibility study of bio-radar technology (system and data processing) for vital signs detection and

  9. Parametric kernel-driven active contours for image segmentation

    NASA Astrophysics Data System (ADS)

    Wu, Qiongzhi; Fang, Jiangxiong

    2012-10-01

    We investigated a parametric kernel-driven active contour (PKAC) model, which implicitly transfers kernel mapping and piecewise constant to modeling the image data via kernel function. The proposed model consists of curve evolution functional with three terms: global kernel-driven and local kernel-driven terms, which evaluate the deviation of the mapped image data within each region from the piecewise constant model, and a regularization term expressed as the length of the evolution curves. In the local kernel-driven term, the proposed model can effectively segment images with intensity inhomogeneity by incorporating the local image information. By balancing the weight between the global kernel-driven term and the local kernel-driven term, the proposed model can segment the images with either intensity homogeneity or intensity inhomogeneity. To ensure the smoothness of the level set function and reduce the computational cost, the distance regularizing term is applied to penalize the deviation of the level set function and eliminate the requirement of re-initialization. Compared with the local image fitting model and local binary fitting model, experimental results show the advantages of the proposed method in terms of computational efficiency and accuracy.

  10. Figure-ground interaction in the human visual cortex.

    PubMed

    Appelbaum, Lawrence G; Wade, Alex R; Pettet, Mark W; Vildavski, Vladimir Y; Norcia, Anthony M

    2008-07-18

    Discontinuities in feature maps serve as important cues for the location of object boundaries. Here we used multi-input nonlinear analysis methods and EEG source imaging to assess the role of several different boundary cues in visual scene segmentation. Synthetic figure/ground displays portraying a circular figure region were defined solely by differences in the temporal frequency of the figure and background regions in the limiting case and by the addition of orientation or relative alignment cues in other cases. The use of distinct temporal frequencies made it possible to separately record responses arising from each region and to characterize the nature of nonlinear interactions between the two regions as measured in a set of retinotopically and functionally defined cortical areas. Figure/background interactions were prominent in retinotopic areas, and in an extra-striate region lying dorsal and anterior to area MT+. Figure/background interaction was greatly diminished by the elimination of orientation cues, the introduction of small gaps between the two regions, or by the presence of a constant second-order border between regions. Nonlinear figure/background interactions therefore carry spatially precise, time-locked information about the continuity/discontinuity of oriented texture fields. This information is widely distributed throughout occipital areas, including areas that do not display strong retinotopy.

  11. Figure-ground modulation in awake primate thalamus

    PubMed Central

    Jones, Helen E.; Andolina, Ian M.; Shipp, Stewart D.; Adams, Daniel L.; Cudeiro, Javier; Salt, Thomas E.; Sillito, Adam M.

    2015-01-01

    Figure-ground discrimination refers to the perception of an object, the figure, against a nondescript background. Neural mechanisms of figure-ground detection have been associated with feedback interactions between higher centers and primary visual cortex and have been held to index the effect of global analysis on local feature encoding. Here, in recordings from visual thalamus of alert primates, we demonstrate a robust enhancement of neuronal firing when the figure, as opposed to the ground, component of a motion-defined figure-ground stimulus is located over the receptive field. In this paradigm, visual stimulation of the receptive field and its near environs is identical across both conditions, suggesting the response enhancement reflects higher integrative mechanisms. It thus appears that cortical activity generating the higher-order percept of the figure is simultaneously reentered into the lowest level that is anatomically possible (the thalamus), so that the signature of the evolving representation of the figure is imprinted on the input driving it in an iterative process. PMID:25901330

  12. Figure-ground modulation in awake primate thalamus.

    PubMed

    Jones, Helen E; Andolina, Ian M; Shipp, Stewart D; Adams, Daniel L; Cudeiro, Javier; Salt, Thomas E; Sillito, Adam M

    2015-06-02

    Figure-ground discrimination refers to the perception of an object, the figure, against a nondescript background. Neural mechanisms of figure-ground detection have been associated with feedback interactions between higher centers and primary visual cortex and have been held to index the effect of global analysis on local feature encoding. Here, in recordings from visual thalamus of alert primates, we demonstrate a robust enhancement of neuronal firing when the figure, as opposed to the ground, component of a motion-defined figure-ground stimulus is located over the receptive field. In this paradigm, visual stimulation of the receptive field and its near environs is identical across both conditions, suggesting the response enhancement reflects higher integrative mechanisms. It thus appears that cortical activity generating the higher-order percept of the figure is simultaneously reentered into the lowest level that is anatomically possible (the thalamus), so that the signature of the evolving representation of the figure is imprinted on the input driving it in an iterative process.

  13. Localized Patch-Based Fuzzy Active Contours for Image Segmentation

    PubMed Central

    Liu, Huaxiang; Zhang, Liting; Liu, Jun

    2016-01-01

    This paper presents a novel fuzzy region-based active contour model for image segmentation. By incorporating local patch-energy functional along each pixel of the evolving curve into the fuzziness of the energy, we construct a patch-based energy function without the regurgitation term. Its purpose is not only to make the active contour evolve very stably without the periodical initialization during the evolution but also to reduce the effect of noise. In particular, in order to reject local minimal of the energy functional, we utilize a direct method to calculate the energy alterations instead of solving the Euler-Lagrange equation of the underlying problem. Compared with other fuzzy active contour models, experimental results on synthetic and real images show the advantages of the proposed method in terms of computational efficiency and accuracy. PMID:28070210

  14. Simultaneous reconstruction of the activity image and registration of the CT image in TOF-PET

    NASA Astrophysics Data System (ADS)

    Rezaei, Ahmadreza; Michel, Christian; Casey, Michael E.; Nuyts, Johan

    2016-02-01

    Previously, maximum-likelihood methods have been proposed to jointly estimate the activity image and the attenuation image or the attenuation sinogram from time-of-flight (TOF) positron emission tomography (PET) data. In this contribution, we propose a method that addresses the possible alignment problem of the TOF-PET emission data and the computed tomography (CT) attenuation data, by combining reconstruction and registration. The method, called MLRR, iteratively reconstructs the activity image while registering the available CT-based attenuation image, so that the pair of activity and attenuation images maximise the likelihood of the TOF emission sinogram. The algorithm is slow to converge, but some acceleration could be achieved by using Nesterov’s momentum method and by applying a multi-resolution scheme for the non-rigid displacement estimation. The latter also helps to avoid local optima, although convergence to the global optimum cannot be guaranteed. The results are evaluated on 2D and 3D simulations as well as a respiratory gated clinical scan. Our experiments indicate that the proposed method is able to correct for possible misalignment of the CT-based attenuation image, and is therefore a very promising approach to suppressing attenuation artefacts in clinical PET/CT. When applied to respiratory gated data of a patient scan, it produced deformations that are compatible with breathing motion and which reduced the well known attenuation artefact near the dome of the liver. Since the method makes use of the energy-converted CT attenuation image, the scale problem of joint reconstruction is automatically solved.

  15. Determination of visual figure and ground in dynamically deforming shapes.

    PubMed

    Barenholtz, Elan; Feldman, Jacob

    2006-10-01

    Figure/ground assignment - determining which part of the visual image is foreground and which background - is a critical step in early visual analysis, upon which much later processing depends. Previous research on the assignment of figure and ground to opposing sides of a contour has almost exclusively involved static geometric factors - such as convexity, symmetry, and size - in non-moving images. Here, we introduce a new class of cue to figural assignment based on the motion of dynamically deforming contours. Subjects viewing an animated, deforming shape tended to assign figure and ground so that articulating curvature extrema - i.e., "hinging" vertices - had negative (concave) contour curvature. This articulating-concavity bias is present when all known static cues to figure/ground are absent or neutral in each of the individual frames of the animation, and even seems to override a number of well-known static cues when they are in opposition to the motion cue. We propose that the phenomenon reflects the visual system's inbuilt expectations about the way shapes will deform - specifically, that deformations tend to involve rigid parts articulating at concavities.

  16. PHOBOS Experiment: Figures and Data

    DOE Data Explorer

    The PHOBOS Collaboration

    PHOBOS consists of many silicon detectors surrounding the interaction region. With these detectors physicists can count the total number of produced particles and study the angular distributions of all the products. Physicists know from other branches of physics that a characteristic of phase transitions are fluctuations in physical observables. With the PHOBOS array they look for unusual events or fluctuations in the number of particles and angular distribution. The articles that have appeared in refereed science journals are listed here with separate links to the supporting data plots, figures, and tables of numeric data.  See also supporting data for articles in technical journals at http://www.phobos.bnl.gov/Publications/Technical/phobos_technical_publications.htm and from conference proceedings at http://www.phobos.bnl.gov/Publications/Proceedings/phobos_proceedings_publications.htm

  17. The role of attention in figure-ground segregation in areas V1 and V4 of the visual cortex.

    PubMed

    Poort, Jasper; Raudies, Florian; Wannig, Aurel; Lamme, Victor A F; Neumann, Heiko; Roelfsema, Pieter R

    2012-07-12

    Our visual system segments images into objects and background. Figure-ground segregation relies on the detection of feature discontinuities that signal boundaries between the figures and the background and on a complementary region-filling process that groups together image regions with similar features. The neuronal mechanisms for these processes are not well understood and it is unknown how they depend on visual attention. We measured neuronal activity in V1 and V4 in a task where monkeys either made an eye movement to texture-defined figures or ignored them. V1 activity predicted the timing and the direction of the saccade if the figures were task relevant. We found that boundary detection is an early process that depends little on attention, whereas region filling occurs later and is facilitated by visual attention, which acts in an object-based manner. Our findings are explained by a model with local, bottom-up computations for boundary detection and feedback processing for region filling.

  18. Finding Figurative Language in "The Phantom Tollbooth."

    ERIC Educational Resources Information Center

    Hinton, Lisa

    This lesson is an exploration of figurative language using the novel "The Phantom Tollbooth" and various Web resources. Students examine figurative language in the story and create a chart representing the literal and figurative meanings of words and phrases. During the four to eight 40-minute class sessions, middle school students will: read the…

  19. High-speed compressive range imaging based on active illumination.

    PubMed

    Sun, Yangyang; Yuan, Xin; Pang, Shuo

    2016-10-03

    We report a compressive imaging method based on active illumination, which reconstructs a 3D scene at a frame rate beyond the acquisition speed limit of the camera. We have built an imaging prototype that projects temporally varying illumination pattern and demonstrated a joint reconstruction algorithm that iteratively retrieves both the range and high-temporal-frequency information from the 2D low-frame rate measurement. The reflectance and depth-map videos have been reconstructed at 1000 frames per second (fps) from the measurement captured at 200 fps. The range resolution is in agreement with the resolution calculated from the triangulation methods based on the same system geometry. We expect such an imaging method could become a simple solution to a wide range of applications, including industrial metrology, 3D printing, and vehicle navigations.

  20. A simple and effective figure caption detection system for old-style documents

    NASA Astrophysics Data System (ADS)

    Liu, Zongyi; Zhou, Hanning

    2011-01-01

    Identifying figure captions has wide applications in producing high quality e-books such as kindle books or ipad books. In this paper, we present a rule-based system to detect horizontal figure captions in old-style documents. Our algorithm consists of three steps: (i) segment images into regions of different types such as text and figures, (ii) search the best caption region candidate based on heuristic rules such as region alignments and distances, and (iii) expand caption regions identified in step (ii) with its neighboring text-regions in order to correct oversegmentation errors. We test our algorithm using 81 images collected from old-style books, with each image containing at least one figure area. We show that the approach is able to correctly detect figure captions from images with different layouts, and we also measure its performances in terms of both precision rate and recall rate.

  1. Simultaneous water activation and glucose metabolic rate imaging with PET

    NASA Astrophysics Data System (ADS)

    Verhaeghe, Jeroen; Reader, Andrew J.

    2013-02-01

    A novel imaging and signal separation strategy is proposed to be able to separate [18F]FDG and multiple [15O]H2O signals from a simultaneously acquired dynamic PET acquisition of the two tracers. The technique is based on the fact that the dynamics of the two tracers are very distinct. By adopting an appropriate bolus injection strategy and by defining tailored sets of basis functions that model either the FDG or water component, it is possible to separate the FDG and water signal. The basis functions are inspired from the spectral analysis description of dynamic PET studies and are defined as the convolution of estimated generating functions (GFs) with a set of decaying exponential functions. The GFs are estimated from the overall measured head curve, while the decaying exponential functions are pre-determined. In this work, the time activity curves (TACs) are modelled post-reconstruction but the model can be incorporated in a global 4D reconstruction strategy. Extensive PET simulation studies are performed considering single [18F]FDG and 6 [15O]H2O bolus injections for a total acquisition time of 75 min. The proposed method is evaluated at multiple noise levels and different parameters were estimated such as [18F]FDG uptake and blood flow estimated from the [15O]H2O component, requiring a full dynamic analysis of the two components, static images of [18F]FDG and the water components as well as [15O]H2O activation. It is shown that the resulting images and parametric values in ROIs are comparable to images obtained from separate imaging, illustrating the feasibility of simultaneous imaging of [18F]FDG and [15O]H2O components. For more information on this article, see medicalphysicsweb.org

  2. Non-line-of-sight active imaging of scattered photons

    NASA Astrophysics Data System (ADS)

    Laurenzis, Martin; Velten, Andreas

    2013-10-01

    Laser Gated Viewing is a prominent sensing technology for optical imaging in harsh environments and can be applied to the vision through fog, smoke and other degraded environmental conditions as well as to the vision through sea water in submarine operation. A direct imaging of non-scattered photons (or ballistic photons) is limited in range and performance by the free optical path length i.e. the length in which a photon can propagate without interaction with scattering particles or object surfaces. The imaging and analysis of scattered photons can overcome these classical limitations and it is possible to realize a non-line-of-sight imaging. The spatial and temporal distribution of scattered photons can be analyzed by means of computational optics and their information of the scenario can be restored. In the case of Lambertian scattering sources the scattered photons carry information of the complete environment. Especial the information outside the line of sight or outside the visibility range is of high interest. Here, we discuss approaches for non line of sight active imaging with different indirect and direct illumination concepts (point, surface and volume scattering sources).

  3. Human brain activity with functional NIR optical imager

    NASA Astrophysics Data System (ADS)

    Luo, Qingming

    2001-08-01

    In this paper we reviewed the applications of functional near infrared optical imager in human brain activity. Optical imaging results of brain activity, including memory for new association, emotional thinking, mental arithmetic, pattern recognition ' where's Waldo?, occipital cortex in visual stimulation, and motor cortex in finger tapping, are demonstrated. It is shown that the NIR optical method opens up new fields of study of the human population, in adults under conditions of simulated or real stress that may have important effects upon functional performance. It makes practical and affordable for large populations the complex technology of measuring brain function. It is portable and low cost. In cognitive tasks subjects could report orally. The temporal resolution could be millisecond or less in theory. NIR method will have good prospects in exploring human brain secret.

  4. Activity-based imaging probes of the proteasome.

    PubMed

    Carmony, Kimberly Cornish; Kim, Kyung Bo

    2013-09-01

    Over the years, the proteasome has been extensively investigated due to its crucial roles in many important signaling pathways and its implications in diseases. Two proteasome inhibitors--bortezomib and carfilzomib--have received FDA approval for the treatment of multiple myeloma, thereby validating the proteasome as a chemotherapeutic target. As a result, further research efforts have been focused on dissecting the complex biology of the proteasome to gain the insight required for developing next-generation proteasome inhibitors. It is clear that chemical probes have made significant contributions to these efforts, mostly by functioning as inhibitors that selectively block the catalytic activity of proteasomes. Analogues of these inhibitors are now providing additional tools for visualization of catalytically active proteasome subunits, several of which allow real-time monitoring of proteasome activity in living cells as well as in in vivo settings. These imaging probes will provide powerful tools for assessing the efficacy of proteasome inhibitors in clinical settings. In this review, we will focus on the recent efforts towards developing imaging probes of proteasomes, including the latest developments in immunoproteasome-selective imaging probes.

  5. Passive and active thermal nondestructive imaging of materials

    NASA Astrophysics Data System (ADS)

    Avdelidis, Nicolas P.; Moropoulou, Antonia; Almond, Darryl P.

    2004-12-01

    Thermal non-destructive approaches, passive and active, are widely used due to the outstanding advantages that offer in a number of applications and particularly for the assessment of materials and structures. In this work, different applications, employing either MWIR or LWIR thermographic testing, as well as passive and/or active approaches, depending on the application, concerning the assessment of various materials are presented. In a few instances, thermal modelling is also discussed and compared with the outcome of experimental testing. The following applications are reviewed: × Emissivity measurements. × Moisture impact assessment in porous materials. × Evaluation of conservation interventions, concerning: - Consolidation interventions on porous stone. - Cleaning of architectural surfaces. × Assessment of airport pavements. × Investigation of repaired aircraft panels. × Through skin sensing assessment on aircraft composite structures. Real time monitoring of all features was obtained using passive imaging or transient thermographic analysis (active imaging). However, in the composite repairs and through skin imaging cases thermal modelling was also used with the intention of providing supplementary results, as well as to demonstrate the importance of thermal contact resistance between two surfaces (skin and strut in through skin sensing). Finally, in order to obtain useful information from the surveys, various properties (thermal, optical, physical) of the examined materials were taken into account.

  6. Ambiguous benefits: the effect of bilingualism on reversing ambiguous figures.

    PubMed

    Bialystok, Ellen; Shapero, Dana

    2005-11-01

    Two studies are reported in which monolingual and bilingual children, approximately 6 years old, attempted to identify the alternative image in a reversible figure. In both studies, bilingual children were more successful than monolinguals in seeing the other meaning in the images. In the first study, there was no relation between the ability to reverse the interpretation and performance on the children's embedded figures task, a task that superficially appeared to involve similar processes. The second study replicated this finding but showed that performance was strongly related to success in the post-switch phase of the dimensional change card sort task. In both cases, the meaning of an image must be reassigned, and bilinguals were better in both these tasks.

  7. Figure-Ground Organization in Visual Cortex for Natural Scenes

    PubMed Central

    2016-01-01

    Abstract Figure-ground organization and border-ownership assignment are essential for understanding natural scenes. It has been shown that many neurons in the macaque visual cortex signal border-ownership in displays of simple geometric shapes such as squares, but how well these neurons resolve border-ownership in natural scenes is not known. We studied area V2 neurons in behaving macaques with static images of complex natural scenes. We found that about half of the neurons were border-ownership selective for contours in natural scenes, and this selectivity originated from the image context. The border-ownership signals emerged within 70 ms after stimulus onset, only ∼30 ms after response onset. A substantial fraction of neurons were highly consistent across scenes. Thus, the cortical mechanisms of figure-ground organization are fast and efficient even in images of complex natural scenes. Understanding how the brain performs this task so fast remains a challenge. PMID:28058269

  8. Riverine Imaging

    DTIC Science & Technology

    2011-12-16

    Tab -1 Information -Theoretic Analysis & Performance Bounds for Super- Resolution (SR) Video Imagery Reconstruction Tab - 2 Appendix: Riverine Imaging...Figure 27 Range Doppler Map of Reduced 7 Point Model 20 Figure 28 Frequency vs Doppler and Frequency vs Velocity Maps of Reduced 7 Point Model 21 Figure...curve) chamber background subtracted 45 Figure 52: Predicted SNR vs . Range Performance for the Akela Radar with 500 mW Power Amp Based on Noise Power

  9. Direct imaging of macrophage activation during PDT treatment

    NASA Astrophysics Data System (ADS)

    Song, Sheng; Zhou, Feifan; Chen, Wei R.; Xing, Da

    2012-03-01

    Mounting evidence describes a more complex progress of macrophage activation during photodynamic therapy (PDT), which performing distinct immunological functions and different physiologies on surrounding cells and tissues. Macrophage-targeted PDT has been applied in the selective killing of cells involved in inflammation and tumor. We have previously shown that PDT-mediated tumor cells apoptosis can induce a higher level immune response than necrosis, and enhance the macrophage activation. However, the molecular mechanism of macrophage activation during PDT-induced apoptotic cells (AC) still unclear. Here, we use confocal microscopy to image the phagocytosis of tumor cells by macrophages. We also observed that PDT-treated AC can activate Toll-like receptors (TLRs) which are present on macrophages surface. Besides, the increase in nitric oxide (NO) formation in macrophages was detected in real time by a laser scanning microscopy. This study provided more details for understanding the molecular mechanism of the immune response induced by PDT-treated AC.

  10. Direct imaging of macrophage activation during PDT treatment

    NASA Astrophysics Data System (ADS)

    Song, Sheng; Zhou, Feifan; Chen, Wei R.; Xing, Da

    2011-11-01

    Mounting evidence describes a more complex progress of macrophage activation during photodynamic therapy (PDT), which performing distinct immunological functions and different physiologies on surrounding cells and tissues. Macrophage-targeted PDT has been applied in the selective killing of cells involved in inflammation and tumor. We have previously shown that PDT-mediated tumor cells apoptosis can induce a higher level immune response than necrosis, and enhance the macrophage activation. However, the molecular mechanism of macrophage activation during PDT-induced apoptotic cells (AC) still unclear. Here, we use confocal microscopy to image the phagocytosis of tumor cells by macrophages. We also observed that PDT-treated AC can activate Toll-like receptors (TLRs) which are present on macrophages surface. Besides, the increase in nitric oxide (NO) formation in macrophages was detected in real time by a laser scanning microscopy. This study provided more details for understanding the molecular mechanism of the immune response induced by PDT-treated AC.

  11. Creating metaphors: The neural basis of figurative language production☆

    PubMed Central

    Benedek, Mathias; Beaty, Roger; Jauk, Emanuel; Koschutnig, Karl; Fink, Andreas; Silvia, Paul J.; Dunst, Beate; Neubauer, Aljoscha C.

    2014-01-01

    Neuroscience research has thoroughly studied how nonliteral language is processed during metaphor comprehension. However, it is not clear how the brain actually creates nonliteral language. Therefore, the present study for the first time investigates the neural correlates of metaphor production. Participants completed sentences by generating novel metaphors or literal synonyms during functional imaging. Responses were spoken aloud in the scanner, recorded, and subsequently rated for their creative quality. We found that metaphor production was associated with focal activity in predominantly left-hemispheric brain regions, specifically the left angular gyrus, the left middle and superior frontal gyri—corresponding to the left dorsomedial prefrontal (DMPFC) cortex—and the posterior cingulate cortex. Moreover, brain activation in the left anterior DMPFC and the right middle temporal gyrus was found to linearly increase with the creative quality of metaphor responses. These findings are related to neuroscientific evidence on metaphor comprehension, creative idea generation and episodic future thought, suggesting that creating metaphors involves the flexible adaptation of semantic memory to imagine and construct novel figures of speech. Furthermore, the left DMPFC may exert executive control to maintain strategic search and selection, thus facilitating creativity of thought. PMID:24384149

  12. Optical imaging of neural and hemodynamic brain activity

    NASA Astrophysics Data System (ADS)

    Schei, Jennifer Lynn

    Optical imaging technologies can be used to record neural and hemodynamic activity. Neural activity elicits physiological changes that alter the optical tissue properties. Specifically, changes in polarized light are concomitant with neural depolarization. We measured polarization changes from an isolated lobster nerve during action potential propagation using both reflected and transmitted light. In transmission mode, polarization changes were largest throughout the center of the nerve, suggesting that most of the optical signal arose from the inner nerve bundle. In reflection mode, polarization changes were largest near the edges, suggesting that most of the optical signal arose from the outer sheath. To overcome irregular cell orientation found in the brain, we measured polarization changes from a nerve tied in a knot. Our results show that neural activation produces polarization changes that can be imaged even without regular cell orientations. Neural activation expends energy resources and elicits metabolic delivery through blood vessel dilation, increasing blood flow and volume. We used spectroscopic imaging techniques combined with electrophysiological measurements to record evoked neural and hemodynamic responses from the auditory cortex of the rat. By using implantable optics, we measured responses across natural wake and sleep states, as well as responses following different amounts of sleep deprivation. During quiet sleep, evoked metabolic responses were larger compared to wake, perhaps because blood vessels were more compliant. When animals were sleep deprived, evoked hemodynamic responses were smaller following longer periods of deprivation. These results suggest that prolonged neural activity through sleep deprivation may diminish vascular compliance as indicated by the blunted vascular response. Subsequent sleep may allow vessels to relax, restoring their ability to deliver blood. These results also suggest that severe sleep deprivation or chronic

  13. Two critical periods in early visual cortex during figure-ground segregation.

    PubMed

    Wokke, Martijn E; Sligte, Ilja G; Steven Scholte, H; Lamme, Victor A F

    2012-11-01

    The ability to distinguish a figure from its background is crucial for visual perception. To date, it remains unresolved where and how in the visual system different stages of figure-ground segregation emerge. Neural correlates of figure border detection have consistently been found in early visual cortex (V1/V2). However, areas V1/V2 have also been frequently associated with later stages of figure-ground segregation (such as border ownership or surface segregation). To causally link activity in early visual cortex to different stages of figure-ground segregation, we briefly disrupted activity in areas V1/V2 at various moments in time using transcranial magnetic stimulation (TMS). Prior to stimulation we presented stimuli that made it possible to differentiate between figure border detection and surface segregation. We concurrently recorded electroencephalographic (EEG) signals to examine how neural correlates of figure-ground segregation were affected by TMS. Results show that disruption of V1/V2 in an early time window (96-119 msec) affected detection of figure stimuli and affected neural correlates of figure border detection, border ownership, and surface segregation. TMS applied in a relatively late time window (236-259 msec) selectively deteriorated performance associated with surface segregation. We conclude that areas V1/V2 are not only essential in an early stage of figure-ground segregation when figure borders are detected, but subsequently causally contribute to more sophisticated stages of figure-ground segregation such as surface segregation.

  14. Neural Correlates of Metaphor Processing: The Roles of Figurativeness, Familiarity and Difficulty

    PubMed Central

    Schmidt, Gwenda L.; Seger, Carol A.

    2009-01-01

    There is currently much interest in investigating the neural substrates of metaphor processing. In particular, it has been suggested that the right hemisphere plays a special role in the comprehension of figurative (non-literal) language, and in particular metaphors. However, some studies find no evidence of right hemisphere involvement in metaphor comprehension (e.g. Lee & Dapretto, 2006; Rapp et al., 2004). We suggest that lateralization differences between literal and metaphorical language may be due to factors such as differences in familiarity (Schmidt et al., 2007), or difficulty (Bookheimer, 2002; Rapp et al., 2004) in addition to figurativeness. The purpose of this study was to separate the effects of figurativeness, familiarity, and difficulty on the recruitment of neural systems involved in language, in particular right hemisphere mechanisms. This was achieved by comparing neural activation using functional magnetic resonance imaging (fMRI) between four conditions: literal sentences, familiar and easy to understand metaphors, unfamiliar and easy to understand metaphors, and unfamiliar and difficult to understand metaphors. Metaphors recruited the right insula, left temporal pole and right inferior frontal gyrus in comparison with literal sentences. Familiar metaphors recruited the right middle frontal gyrus when contrasted with unfamiliar metaphors. Easy metaphors showed higher activation in the left middle frontal gyrus as compared to difficult metaphors, while difficult metaphors showed selective activation in the left inferior frontal gyrus as compared to easy metaphors. We conclude that the right hemisphere is involved in metaphor processing and that the factors of figurativeness, familiarity and difficulty are important in determining neural recruitment of semantic processing. PMID:19586700

  15. Semantic-gap-oriented active learning for multilabel image annotation.

    PubMed

    Tang, Jinhui; Zha, Zheng-Jun; Tao, Dacheng; Chua, Tat-Seng

    2012-04-01

    User interaction is an effective way to handle the semantic gap problem in image annotation. To minimize user effort in the interactions, many active learning methods were proposed. These methods treat the semantic concepts individually or correlatively. However, they still neglect the key motivation of user feedback: to tackle the semantic gap. The size of the semantic gap of each concept is an important factor that affects the performance of user feedback. User should pay more efforts to the concepts with large semantic gaps, and vice versa. In this paper, we propose a semantic-gap-oriented active learning method, which incorporates the semantic gap measure into the information-minimization-based sample selection strategy. The basic learning model used in the active learning framework is an extended multilabel version of the sparse-graph-based semisupervised learning method that incorporates the semantic correlation. Extensive experiments conducted on two benchmark image data sets demonstrated the importance of bringing the semantic gap measure into the active learning process.

  16. Figure Control of Lightweight Optical Structures

    NASA Technical Reports Server (NTRS)

    Main, John A.; Song, Haiping

    2005-01-01

    The goal of this paper is to demonstrate the use of fuzzy logic controllers in modifying the figure of a piezoceramic bimorph mirror. Non-contact electron actuation technology is used to actively control a bimorph mirror comprised two PZT-5H wafers by varying the electron flux and electron voltages. Due to electron blooming generated by the electron flux, it is difficult to develop an accurate control model for the bimorph mirror through theoretical analysis alone. The non-contact shape control system with electron flux blooming can be approximately described with a heuristic model based on experimental data. Two fuzzy logic feedback controllers are developed to control the shape of the bimorph mirror according to heuristic fuzzy inference rules generated from previous experimental results. Validation of the proposed fuzzy logic controllers is also discussed.

  17. "Old Dead Guys": Using Activity Breaks to Teach History

    ERIC Educational Resources Information Center

    Holles, Joseph H.

    2009-01-01

    The people and history of chemical engineering surround us: Gibbs free energy, Arrhenius Equation, and Reynolds number. Since these seminal figures appear in almost every classroom lecture, they provide an opportunity for a historically focused activity break. Each activity break provides the students with an image of the historical figure along…

  18. Quantitative phase imaging technologies to assess neuronal activity (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Thouvenin, Olivier; Fink, Mathias; Boccara, Claude

    2016-03-01

    Active neurons tends to have a different dynamical behavior compared to resting ones. Non-exhaustively, vesicular transport towards the synapses is increased, since axonal growth becomes slower. Previous studies also reported small phase variations occurring simultaneously with the action potential. Such changes exhibit times scales ranging from milliseconds to several seconds on spatial scales smaller than the optical diffraction limit. Therefore, QPI systems are of particular interest to measure neuronal activity without labels. Here, we report the development of two new QPI systems that should enable the detection of such activity. Both systems can acquire full field phase images with a sub nanometer sensitivity at a few hundreds of frames per second. The first setup is a synchronous combination of Full Field Optical Coherence Tomography (FF-OCT) and Fluorescence wide field imaging. The latter modality enables the measurement of neurons electrical activity using calcium indicators. In cultures, FF-OCT exhibits similar features to Digital Holographic Microscopy (DHM), except from complex computational reconstruction. However, FF-OCT is of particular interest in order to measure phase variations in tissues. The second setup is based on a Quantitative Differential Interference Contrast setup mounted in an epi-illumination configuration with a spectrally incoherent illumination. Such a common path interferometer exhibits a very good mechanical stability, and thus enables the measurement of phase images during hours. Additionally, such setup can not only measure a height change, but also an optical index change for both polarization. Hence, one can measure simultaneously a phase change and a birefringence change.

  19. High-throughput imaging of neuronal activity in Caenorhabditis elegans

    PubMed Central

    Larsch, Johannes; Ventimiglia, Donovan; Bargmann, Cornelia I.; Albrecht, Dirk R.

    2013-01-01

    Neuronal responses to sensory inputs can vary based on genotype, development, experience, or stochastic factors. Existing neuronal recording techniques examine a single animal at a time, limiting understanding of the variability and range of potential responses. To scale up neuronal recordings, we here describe a system for simultaneous wide-field imaging of neuronal calcium activity from at least 20 Caenorhabditis elegans animals under precise microfluidic chemical stimulation. This increased experimental throughput was used to perform a systematic characterization of chemosensory neuron responses to multiple odors, odor concentrations, and temporal patterns, as well as responses to pharmacological manipulation. The system allowed recordings from sensory neurons and interneurons in freely moving animals, whose neuronal responses could be correlated with behavior. Wide-field imaging provides a tool for comprehensive circuit analysis with elevated throughput in C. elegans. PMID:24145415

  20. Superresolution Imaging of Amyloid Fibrils with Binding-Activated Probes

    PubMed Central

    2013-01-01

    Protein misfolding into amyloid-like aggregates underlies many neurodegenerative diseases. Thus, insights into the structure and function of these amyloids will provide valuable information on the pathological mechanisms involved and aid in the design of improved drugs for treating amyloid-based disorders. However, determining the structure of endogenous amyloids at high resolution has been difficult. Here we employ binding-activated localization microscopy (BALM) to acquire superresolution images of α-synuclein amyloid fibrils with unprecedented optical resolution. We propose that BALM imaging can be extended to study the structure of other amyloids, for differential diagnosis of amyloid-related diseases and for discovery of drugs that perturb amyloid structure for therapy. PMID:23594172

  1. Active Volcano Monitoring using a Space-based Hyperspectral Imager

    NASA Astrophysics Data System (ADS)

    Cipar, J. J.; Dunn, R.; Cooley, T.

    2010-12-01

    Active volcanoes occur on every continent, often in close proximity to heavily populated areas. While ground-based studies are essential for scientific research and disaster mitigation, remote sensing from space can provide rapid and continuous monitoring of active and potentially active volcanoes [Ramsey and Flynn, 2004]. In this paper, we report on hyperspectral measurements of Kilauea volcano, Hawaii. Hyperspectral images obtained by the US Air Force TacSat-3/ARTEMIS sensor [Lockwood et al, 2006] are used to obtain estimates of the surface temperatures for the volcano. ARTEMIS measures surface-reflected light in the visible, near-infrared, and short-wave infrared bands (VNIR-SWIR). The SWIR bands are known to be sensitive to thermal radiation [Green, 1996]. For example, images from the NASA Hyperion hyperspectral sensor have shown the extent of wildfires and active volcanoes [Young, 2009]. We employ the methodology described by Dennison et al, (2006) to obtain an estimate of the temperature of the active region of Kilauea. Both day and night-time images were used in the analysis. To improve the estimate, we aggregated neighboring pixels. The active rim of the lava lake is clearly discernable in the temperature image, with a measured temperature exceeding 1100o C. The temperature decreases markedly on the exterior of the summit crater. While a long-wave infrared (LWIR) sensor would be ideal for volcano monitoring, we have shown that the thermal state of an active volcano can be monitored using the SWIR channels of a reflective hyperspectral imager. References: Dennison, Philip E., Kraivut Charoensiri, Dar A. Roberts, Seth H. Peterson, and Robert O. Green (2006). Wildfire temperature and land cover modeling using hyperspectral data, Remote Sens. Environ., vol. 100, pp. 212-222. Green, R. O. (1996). Estimation of biomass fire temperature and areal extent from calibrated AVIRIS spectra, in Summaries of the 6th Annual JPL Airborne Earth Science Workshop, Pasadena, CA

  2. Quantitative evaluation of activation state in functional brain imaging.

    PubMed

    Hu, Zhenghui; Ni, Pengyu; Liu, Cong; Zhao, Xiaohu; Liu, Huafeng; Shi, Pengcheng

    2012-10-01

    Neuronal activity can evoke the hemodynamic change that gives rise to the observed functional magnetic resonance imaging (fMRI) signal. These increases are also regulated by the resting blood volume fraction (V (0)) associated with regional vasculature. The activation locus detected by means of the change in the blood-oxygen-level-dependent (BOLD) signal intensity thereby may deviate from the actual active site due to varied vascular density in the cortex. Furthermore, conventional detection techniques evaluate the statistical significance of the hemodynamic observations. In this sense, the significance level relies not only upon the intensity of the BOLD signal change, but also upon the spatially inhomogeneous fMRI noise distribution that complicates the expression of the results. In this paper, we propose a quantitative strategy for the calibration of activation states to address these challenging problems. The quantitative assessment is based on the estimated neuronal efficacy parameter [Formula: see text] of the hemodynamic model in a voxel-by-voxel way. It is partly immune to the inhomogeneous fMRI noise by virtue of the strength of the optimization strategy. Moreover, it is easy to incorporate regional vascular information into the activation detection procedure. By combining MR angiography images, this approach can remove large vessel contamination in fMRI signals, and provide more accurate functional localization than classical statistical techniques for clinical applications. It is also helpful to investigate the nonlinear nature of the coupling between synaptic activity and the evoked BOLD response. The proposed method might be considered as a potentially useful complement to existing statistical approaches.

  3. Local spectral anisotropy is a valid cue for figure-ground organization in natural scenes

    PubMed Central

    Ramenahalli, Sudarshan; Mihalas, Stefan; Niebur, Ernst

    2016-01-01

    An important step in the process of understanding visual scenes is its organization in different perceptual objects which requires figure-ground segregation. The determination which side of an occlusion boundary is figure (closer to the observer) and which is ground (further away from the observer) is made through a combination of global cues, like convexity, and local cues, like T-junctions. We here focus on a novel set of local cues in the intensity patterns along occlusion boundaries which we show to differ between figure and ground. Image patches are extracted from natural scenes from two standard image sets along the boundaries of objects and spectral analysis is performed separately on figure and ground. On the figure side, oriented spectral power orthogonal to the occlusion boundary significantly exceeds that parallel to the boundary. This “spectral anisotropy” is present only for higher spatial frequencies, and absent on the ground side. The difference in spectral anisotropy between the two sides of an occlusion border predicts which is the figure and which the background with an accuracy exceeding 60% per patch. Spectral anisotropy of close-by locations along the boundary co-varies but is largely independent over larger distances which allows to combine results from different image regions. Given the low cost of this strictly local computation, we propose that spectral anisotropy along occlusion boundaries is a valuable cue for figure-ground segregation. A data base of images and extracted patches labeled for figure and ground is made freely available. PMID:25175115

  4. Local spectral anisotropy is a valid cue for figure-ground organization in natural scenes.

    PubMed

    Ramenahalli, Sudarshan; Mihalas, Stefan; Niebur, Ernst

    2014-10-01

    An important step in the process of understanding visual scenes is its organization in different perceptual objects which requires figure-ground segregation. The determination of which side of an occlusion boundary is figure (closer to the observer) and which is ground (further away from the observer) is made through a combination of global cues, like convexity, and local cues, like T-junctions. We here focus on a novel set of local cues in the intensity patterns along occlusion boundaries which we show to differ between figure and ground. Image patches are extracted from natural scenes from two standard image sets along the boundaries of objects and spectral analysis is performed separately on figure and ground. On the figure side, oriented spectral power orthogonal to the occlusion boundary significantly exceeds that parallel to the boundary. This "spectral anisotropy" is present only for higher spatial frequencies, and absent on the ground side. The difference in spectral anisotropy between the two sides of an occlusion border predicts which is the figure and which the background with an accuracy exceeding 60% per patch. Spectral anisotropy of close-by locations along the boundary co-varies but is largely independent over larger distances which allows to combine results from different image regions. Given the low cost of this strictly local computation, we propose that spectral anisotropy along occlusion boundaries is a valuable cue for figure-ground segregation. A data base of images and extracted patches labeled for figure and ground is made freely available.

  5. Selecting Children's Picture Books with Positive Native American Fathers and Father Figures.

    ERIC Educational Resources Information Center

    Heller, Craig; Cunningham, Bruce; Heller, Hannah M.

    2003-01-01

    Explores images of Native American fathers and father figures in children's picture books, offering background information about Native American cultures, traditional ways of culture and family, and the past and present role of fathers and father figures. Presents distinctive children's books along with guidelines for selecting and evaluating…

  6. Recommended reference figures for geophysics and geodesy

    NASA Technical Reports Server (NTRS)

    Khan, M. A.; Okeefe, J. A.

    1973-01-01

    Specific reference figures are recommended for consistent use in geophysics and geodesy. The selection of appropriate reference figure for geophysical studies suggests a relationship between the Antarctic negative gravity anomaly and the great shrinkage of the Antarctic ice cap about 4-5 million years ago. The depression of the south polar regions relative to the north polar regions makes the Southern Hemisphere flatter than the Northern Hemisphere, thus producing the third harmonic (pear-shaped) contribution to the earth's figure.

  7. Calcium imaging of infrared-stimulated activity in rodent brain.

    PubMed

    Cayce, Jonathan Matthew; Bouchard, Matthew B; Chernov, Mykyta M; Chen, Brenda R; Grosberg, Lauren E; Jansen, E Duco; Hillman, Elizabeth M C; Mahadevan-Jansen, Anita

    2014-04-01

    Infrared neural stimulation (INS) is a promising neurostimulation technique that can activate neural tissue with high spatial precision and without the need for exogenous agents. However, little is understood about how infrared light interacts with neural tissue on a cellular level, particularly within the living brain. In this study, we use calcium sensitive dye imaging on macroscopic and microscopic scales to explore the spatiotemporal effects of INS on cortical calcium dynamics. The INS-evoked calcium signal that was observed exhibited a fast and slow component suggesting activation of multiple cellular mechanisms. The slow component of the evoked signal exhibited wave-like properties suggesting network activation, and was verified to originate from astrocytes through pharmacology and 2-photon imaging. We also provide evidence that the fast calcium signal may have been evoked through modulation of glutamate transients. This study demonstrates that pulsed infrared light can induce intracellular calcium modulations in both astrocytes and neurons, providing new insights into the mechanisms of action of INS in the brain.

  8. Segmentation of common carotid artery with active appearance models from ultrasound images

    NASA Astrophysics Data System (ADS)

    Yang, Xin; He, Wanji; Fenster, Aaron; Yuchi, Ming; Ding, Mingyue

    2013-02-01

    Carotid atherosclerosis is a major cause of stroke, a leading cause of death and disability. In this paper, a new segmentation method is proposed and evaluated for outlining the common carotid artery (CCA) from transverse view images, which were sliced from three-dimensional ultrasound (3D US) of 1mm inter-slice distance (ISD), to support the monitoring and assessment of carotid atherosclerosis. The data set consists of forty-eight 3D US images acquired from both left and right carotid arteries of twelve patients in two time points who had carotid stenosis of 60% or more at the baseline. The 3D US data were collected at baseline and three-month follow-up, where seven treated with 80mg atorvastatin and five with placebo. The baseline manual boundaries were used for Active Appearance Models (AAM) training; while the treatment data for segmentation testing and evaluation. The segmentation results were compared with experts manually outlined boundaries, as a surrogate for ground truth, for further evaluation. For the adventitia and lumen segmentations, the algorithm yielded Dice Coefficients (DC) of 92.06%+/-2.73% and 89.67%+/-3.66%, mean absolute distances (MAD) of 0.28+/-0.18 mm and 0.22+/-0.16 mm, maximum absolute distances (MAXD) of 0.71+/-0.28 mm and 0.59+/-0.21 mm, respectively. The segmentation results were also evaluated via Pratt's figure of merit (FOM) with the value of 0.61+/-0.06 and 0.66+/-0.05, which provides a quantitative measure for judging the similarity. Experimental results indicate that the proposed method can promote the carotid 3D US usage for a fast, safe and economical monitoring of the atherosclerotic disease progression and regression during therapy.

  9. Figure-ground assignment in pigeons: evidence for a figural benefit.

    PubMed

    Lazareva, Olga E; Castro, Leyre; Vecera, Shaun P; Wasserman, Edward A

    2006-07-01

    Four pigeons discriminated whether a target spot appeared on a colored figural shape or on a differently colored background by first pecking the target and then reporting its location: on the figure or the background. We recorded three dependent variables: target detection time, choice response time, and choice accuracy. The birds were faster to detect the target, to report its location, and to learn the correct response on figure trials than on background trials. Later tests suggested that the pigeons might have attended to the figural region as a whole rather than using local properties in performing the figure-background discrimination. The location of the figural region did not affect figure-ground assignment. Finally, when 4 other pigeons had to detect and peck the target without making a choice report, no figural advantage emerged in target detection time, suggesting that the birds' attention may not have been automatically summoned to the figural region.

  10. Photon-noise effect on detection in coherent active images.

    PubMed

    Réfrégier, Philippe; Goudail, François; Delyon, Guillaume

    2004-01-15

    We analyze photon-noise effects on target detection performance in low-flux coherent active imagery systems. We show that when photon noise is expected, the performance of classical detection techniques designed for pure and fully developed speckle images can be improved with no increase in algorithm complexity. Furthermore, the mean photon number under which photon noise becomes sensitive is higher when the target and background mean values are unknown than in the idealized case, where they are assumed to be known, and when the reflectivity ratio between the target and the background is low.

  11. Functional evaluation of hidden figures object analysis in children with autistic disorder.

    PubMed

    Malisza, Krisztina L; Clancy, Christine; Shiloff, Deborah; Foreman, Derek; Holden, Jeanette; Jones, Cheryl; Paulson, K; Summers, Randy; Yu, C T; Chudley, Albert E

    2011-01-01

    Functional magnetic resonance imaging (fMRI) during performance of a hidden figures task (HFT) was used to compare differences in brain function in children diagnosed with autism disorder (AD) compared to children with attention-deficit/hyperactivity disorder (ADHD) and typical controls (TC). Overall greater functional MRI activity was observed in the two control groups compared to children with AD. Laterality differences were also evident, with AD subjects preferentially showing activity in the right medial temporal region while controls tended to activate the left medial temporal cortex. Reduced fMRI activity was observed in the parietal, ventral-temporal and hippocampal regions in the AD group, suggesting differences in the way that children with AD process the HFT.

  12. THERMAL IMAGING OF ACTIVE MAGNETIC REGERNERATOR MCE MATERIALS DURING OPERATION

    SciTech Connect

    Shassere, Benjamin; West, David L; Abdelaziz, Omar; Evans III, Boyd Mccutchen

    2012-01-01

    An active magnetic regenerator (AMR) prototype was constructed that incorporates a Gd sheet into the regenerator wall to enable visualization of the system s thermal transients. In this experiment, the thermal conditions inside the AMR are observed under a variety of operating conditions. An infrared (IR) camera is employed to visualize the thermal transients within the AMR. The IR camera is used to visually and quantitatively evaluate the temperature difference and thus giving means to calculate the performance of the system under the various operating conditions. Thermal imaging results are presented for two differing experimental test runs. Real time imaging of the thermal state of the AMR has been conducted while operating the system over a range of conditions. A 1 Tesla twin-coil electromagnet (situated on a C frame base) is used for this experiment such that all components are stationary during testing. A modular, linear reciprocating system has been realized in which the effects of regenerator porosity and utilization factor can be investigated. To evaluate the performance variation in porosity and utilization factor the AMR housing was constructed such that the plate spacing of the Gd sheets may be varied. Each Gd sheet has dimensions of 38 mm wide and 66 mm long with a thickness of 1 mm and the regenerator can hold a maximum of 29 plates with a spacing of 0.25 mm. Quantitative and thermal imaging results are presented for several regenerator configurations.

  13. MCT SWIR modules for passive and active imaging applications

    NASA Astrophysics Data System (ADS)

    Breiter, R.; Benecke, M.; Eich, D.; Figgemeier, H.; Weber, A.; Wendler, J.; Sieck, A.

    2016-05-01

    Based on AIM's state-of-the-art MCT IR technology, detector modules for the SWIR spectral range have been developed, fabricated and characterized. While LPE grown MCT FPAs with extended 2.5μm cut-off have been fabricated and integrated also MBE grown MCT on GaAs is considered for future production. Two imaging applications have been in focus operating either in passive mode by making use of e.g. the night glow, or in active mode by laser illumination for gated viewing. Dedicated readout integrated circuits (ROIC), realized in 0.18μm Si-CMOS technology providing the required functionality for passive imaging and gated imaging, have been designed and implemented. For both designs a 640x512 15μm pitch format was chosen. The FPAs are integrated in compact dewar cooler configurations using AIM's split linear coolers. A command and control electronics (CCE) provides supply voltages, biasing, clocks, control and video digitization for easy system interfacing. For imaging under low-light conditions a low-noise 640x512 15μm pitch ROIC with CTIA input stages and correlated double sampling was designed. The ROIC provides rolling shutter and snapshot integration. To reduce size, weight, power and cost (SWaP-C) a 640x512 format detector in a 10μm pitch is under development. The module makes use of the extended SWIR spectral cut-off up to 2.5μm. To be used for active gated-viewing operation SWIR MCT avalanche photodiodes have been implemented and characterized on FPA level in a 640x512 15μm pitch format. The specific ROIC provides also the necessary functions for range gate control and triggering by the laser illumination. First lab and field tests of a gated viewing demonstrator have been carried out. The paper will present the development status and performance results of AIM's MCT based SWIR Modules for imaging applications.

  14. Exploring Critical Themes through the Human Figure

    ERIC Educational Resources Information Center

    Henderson, Lynette K.

    2013-01-01

    A primary goal of substantive art education is to communicate visually--to decipher art for meaning and to construct meaning through images and objects. Strategies available to engage students are the interdisciplinary activities found in performance, visual and written forms of creative expression, and related disciplines such as ethnography,…

  15. Imaging Active Surface Processes in Barnacle Adhesive Interfaces.

    PubMed

    Golden, Joel P; Burden, Daniel K; Fears, Kenan P; Barlow, Daniel E; So, Christopher R; Burns, Justin; Miltenberg, Benjamin; Orihuela, Beatriz; Rittshof, Daniel; Spillmann, Christopher M; Wahl, Kathryn J; Tender, Leonard M

    2016-01-19

    Surface plasmon resonance imaging (SPRI) and voltammetry were used simultaneously to monitor Amphibalanus (=Balanus) amphitrite barnacles reattached and grown on gold-coated glass slides in artificial seawater. Upon reattachment, SPRI revealed rapid surface adsorption of material with a higher refractive index than seawater at the barnacle/gold interface. Over longer time periods, SPRI also revealed secretory activity around the perimeter of the barnacle along the seawater/gold interface extending many millimeters beyond the barnacle and varying in shape and region with time. Ex situ experiments using attenuated total reflectance infrared (ATR-IR) spectroscopy confirmed that reattachment of barnacles was accompanied by adsorption of protein to surfaces on similar time scales as those in the SPRI experiments. Barnacles were grown through multiple molting cycles. While the initial reattachment region remained largely unchanged, SPRI revealed the formation of sets of paired concentric rings having alternately darker/lighter appearance (corresponding to lower and higher refractive indices, respectively) at the barnacle/gold interface beneath the region of new growth. Ex situ experiments coupling the SPRI imaging with optical and FTIR microscopy revealed that the paired rings coincide with molt cycles, with the brighter rings associated with regions enriched in amide moieties. The brighter rings were located just beyond orifices of cement ducts, consistent with delivery of amide-rich chemistry from the ducts. The darker rings were associated with newly expanded cuticle. In situ voltammetry using the SPRI gold substrate as the working electrode revealed presence of redox active compounds (oxidation potential approx 0.2 V vs Ag/AgCl) after barnacles were reattached on surfaces. Redox activity persisted during the reattachment period. The results reveal surface adsorption processes coupled to the complex secretory and chemical activity under barnacles as they construct

  16. Efficient hyperspectral image segmentation using geometric active contour formulation

    NASA Astrophysics Data System (ADS)

    Albalooshi, Fatema A.; Sidike, Paheding; Asari, Vijayan K.

    2014-10-01

    In this paper, we present a new formulation of geometric active contours that embeds the local hyperspectral image information for an accurate object region and boundary extraction. We exploit self-organizing map (SOM) unsupervised neural network to train our model. The segmentation process is achieved by the construction of a level set cost functional, in which, the dynamic variable is the best matching unit (BMU) coming from SOM map. In addition, we use Gaussian filtering to discipline the deviation of the level set functional from a signed distance function and this actually helps to get rid of the re-initialization step that is computationally expensive. By using the properties of the collective computational ability and energy convergence capability of the active control models (ACM) energy functional, our method optimizes the geometric ACM energy functional with lower computational time and smoother level set function. The proposed algorithm starts with feature extraction from raw hyperspectral images. In this step, the principal component analysis (PCA) transformation is employed, and this actually helps in reducing dimensionality and selecting best sets of the significant spectral bands. Then the modified geometric level set functional based ACM is applied on the optimal number of spectral bands determined by the PCA. By introducing local significant spectral band information, our proposed method is capable to force the level set functional to be close to a signed distance function, and therefore considerably remove the need of the expensive re-initialization procedure. To verify the effectiveness of the proposed technique, we use real-life hyperspectral images and test our algorithm in varying textural regions. This framework can be easily adapted to different applications for object segmentation in aerial hyperspectral imagery.

  17. Feature Assignment in Perception of Auditory Figure

    ERIC Educational Resources Information Center

    Gregg, Melissa K.; Samuel, Arthur G.

    2012-01-01

    Because the environment often includes multiple sounds that overlap in time, listeners must segregate a sound of interest (the auditory figure) from other co-occurring sounds (the unattended auditory ground). We conducted a series of experiments to clarify the principles governing the extraction of auditory figures. We distinguish between auditory…

  18. Key Figures on Vocational Education and Training.

    ERIC Educational Resources Information Center

    Mossoux, Anne France, Ed.

    This brochure identifies key figures on vocational education and training (VET) and VET-related topics in Europe using harmonized data from Eurostat. Throughout, figures of candidate countries are compared to those of European Union (EU) member states. Background information on the education and training systems is as follows: increasing numbers…

  19. "Blessed": Musical Talent, Smartness, & Figured Identities

    ERIC Educational Resources Information Center

    Hoffman, Adria R.

    2015-01-01

    The purpose of this study is to explore smartness and talent as social constructs. Drawing on Holland et al.'s (1998) figured identities, this article explores the figuring of abilities by elucidating the voices of African American high school chorus students. Critical Race Theory (CRT) helps to unpack normalized language and practices that…

  20. Detector array evaluation and figures of merit

    NASA Technical Reports Server (NTRS)

    Dereniak, Eustace L.

    1990-01-01

    The commonly used methods to evaluate the performance of a two-dimensional focal-plane array using charge transfer devices are reviewed. Two figures of merit that attempt to combine quantum efficiency, read noise and dark-current generation into a single parameter are discussed. The figures of merit are suggested as possible alternatives to the D asterisk.

  1. Analysis of That Mysterious Figure 8

    ERIC Educational Resources Information Center

    Leyden, Michael B.

    1974-01-01

    Presents a quantitative analysis of the "figure 8" found on the globes of most earth science textbooks, using an exercise of year's eccentric shadow plotting techniques. Indicates that the exercise can serve to change a student's abstract "figure 8" to his real learning experience. (CC)

  2. The Vernier Caliper and Significant Figures.

    ERIC Educational Resources Information Center

    Oberhofer, E. S.

    1985-01-01

    Misconceptions occur because the caliper is often read with the same significant figures as a meter stick; however, the precision of the vernier caliper is greater than the precision of a meter stick. Clarification of scale reading, precision of both tools, and significant figures are discussed. (JN)

  3. The Development of Ambiguous Figure Perception

    ERIC Educational Resources Information Center

    Wimmer, Marina C.; Doherty, Martin J.

    2011-01-01

    Ambiguous figures have fascinated researchers for almost 200 years. The physical properties of these figures remain constant, yet two distinct interpretations are possible; these reverse (switch) from one percept to the other. The consensus is that reversal requires complex interaction of perceptual bottom-up and cognitive top-down elements. The…

  4. Evolution of the Significant Figure Rules

    ERIC Educational Resources Information Center

    Carter, Ashley R.

    2013-01-01

    Today, almost all introductory physics textbooks include standardized "rules" on how to find the number of significant figures in a calculated value. And yet, 30 years ago these rules were almost nonexistent. Why have we increased the role of significant figures in introductory classes, and should we continue this trend? A look back at…

  5. Bone mineral density in elite adolescent female figure skaters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Elite adolescent figure skaters must accommodate both the physical demands of competitive training and the accelerated rate of bone growth that is associated with adolescence. Although, these athletes apparently undergo sufficient physical activity to develop healthy bones, it is possible that other...

  6. Identity and Figured Worlds of School Technology Use

    ERIC Educational Resources Information Center

    Lessem, Matthew

    2012-01-01

    Technology use in educational contexts is a personal and social activity. It is linked to individuals' attitudes and practices as well as the culture and structure of the institution. This research uses the theoretical framework of "figured worlds" and "self-in practice" to examine identities and cultural practices linked…

  7. Imaging of Common Adult Neurologic Disorders

    PubMed Central

    McLennan, Michael K.; Marotta, Thomas R.; TerBrugge, Karel G.; Marotta, Joseph T.

    1991-01-01

    The family physician is often called upon to diagnose a range of adult neurologic disorders. Clinical history, physical examination, laboratory tests, and imaging studies are required to discover their cause. Various imaging modalities can be used to evaluate common adult disorders of the central nervous system. ImagesFigures 1-2Figure 3Figure 4Figures 5-6Figures 7-8Figures 9-11 PMID:21229013

  8. Nonlinear Dual Reconstruction of SPECT Activity and Attenuation Images

    PubMed Central

    Liu, Huafeng; Guo, Min; Hu, Zhenghui; Shi, Pengcheng; Hu, Hongjie

    2014-01-01

    In single photon emission computed tomography (SPECT), accurate attenuation maps are needed to perform essential attenuation compensation for high quality radioactivity estimation. Formulating the SPECT activity and attenuation reconstruction tasks as coupled signal estimation and system parameter identification problems, where the activity distribution and the attenuation parameter are treated as random variables with known prior statistics, we present a nonlinear dual reconstruction scheme based on the unscented Kalman filtering (UKF) principles. In this effort, the dynamic changes of the organ radioactivity distribution are described through state space evolution equations, while the photon-counting SPECT projection data are measured through the observation equations. Activity distribution is then estimated with sub-optimal fixed attenuation parameters, followed by attenuation map reconstruction given these activity estimates. Such coupled estimation processes are iteratively repeated as necessary until convergence. The results obtained from Monte Carlo simulated data, physical phantom, and real SPECT scans demonstrate the improved performance of the proposed method both from visual inspection of the images and a quantitative evaluation, compared to the widely used EM-ML algorithms. The dual estimation framework has the potential to be useful for estimating the attenuation map from emission data only and thus benefit the radioactivity reconstruction. PMID:25225796

  9. Nonlinear dual reconstruction of SPECT activity and attenuation images.

    PubMed

    Liu, Huafeng; Guo, Min; Hu, Zhenghui; Shi, Pengcheng; Hu, Hongjie

    2014-01-01

    In single photon emission computed tomography (SPECT), accurate attenuation maps are needed to perform essential attenuation compensation for high quality radioactivity estimation. Formulating the SPECT activity and attenuation reconstruction tasks as coupled signal estimation and system parameter identification problems, where the activity distribution and the attenuation parameter are treated as random variables with known prior statistics, we present a nonlinear dual reconstruction scheme based on the unscented Kalman filtering (UKF) principles. In this effort, the dynamic changes of the organ radioactivity distribution are described through state space evolution equations, while the photon-counting SPECT projection data are measured through the observation equations. Activity distribution is then estimated with sub-optimal fixed attenuation parameters, followed by attenuation map reconstruction given these activity estimates. Such coupled estimation processes are iteratively repeated as necessary until convergence. The results obtained from Monte Carlo simulated data, physical phantom, and real SPECT scans demonstrate the improved performance of the proposed method both from visual inspection of the images and a quantitative evaluation, compared to the widely used EM-ML algorithms. The dual estimation framework has the potential to be useful for estimating the attenuation map from emission data only and thus benefit the radioactivity reconstruction.

  10. Probabilistic image modeling with an extended chain graph for human activity recognition and image segmentation.

    PubMed

    Zhang, Lei; Zeng, Zhi; Ji, Qiang

    2011-09-01

    Chain graph (CG) is a hybrid probabilistic graphical model (PGM) capable of modeling heterogeneous relationships among random variables. So far, however, its application in image and video analysis is very limited due to lack of principled learning and inference methods for a CG of general topology. To overcome this limitation, we introduce methods to extend the conventional chain-like CG model to CG model with more general topology and the associated methods for learning and inference in such a general CG model. Specifically, we propose techniques to systematically construct a generally structured CG, to parameterize this model, to derive its joint probability distribution, to perform joint parameter learning, and to perform probabilistic inference in this model. To demonstrate the utility of such an extended CG, we apply it to two challenging image and video analysis problems: human activity recognition and image segmentation. The experimental results show improved performance of the extended CG model over the conventional directed or undirected PGMs. This study demonstrates the promise of the extended CG for effective modeling and inference of complex real-world problems.

  11. 131I activity quantification of gamma camera planar images

    NASA Astrophysics Data System (ADS)

    Barquero, Raquel; Garcia, Hugo P.; Incio, Monica G.; Minguez, Pablo; Cardenas, Alexander; Martínez, Daniel; Lassmann, Michael

    2017-02-01

    A procedure to estimate the activity in target tissues in patients during the therapeutic administration of 131I radiopharmaceutical treatment for thyroid conditions (hyperthyroidism and differentiated thyroid cancer) using a gamma camera (GC) with a high energy (HE) collimator, is proposed. Planar images are acquired for lesions of different sizes r, and at different distances d, in two HE GC systems. Defining a region of interest (ROI) on the image of size r, total counts n g are measured. Sensitivity S (cps MBq-1) in each acquisition is estimated as the product of the geometric G and the intrinsic efficiency η 0. The mean fluence of 364 keV photons arriving at the ROI per disintegration G, is calculated with the MCNPX code, simulating the entire GC and the HE collimator. Intrinsic efficiency η 0 is estimated from a calibration measurement of a plane reference source of 131I in air. Values of G and S for two GC systems—Philips Skylight and Siemens e-cam—are calculated. The total range of possible sensitivity values in thyroidal imaging in the e-cam and skylight GC measure from 7 cps MBq-1 to 35 cps MBq-1, and from 6 cps MBq-1 to 29 cps MBq-1, respectively. These sensitivity values have been verified with the SIMIND code, with good agreement between them. The results have been validated with experimental measurements in air, and in a medium with scatter and attenuation. The counts in the ROI can be produced by direct, scatter and penetration photons. The fluence value for direct photons is constant for any r and d values, but scatter and penetration photons show different values related to specific r and d values, resulting in the large sensitivity differences found. The sensitivity in thyroidal GC planar imaging is strongly dependent on uptake size, and distance from the GC. An individual value for the acquisition sensitivity of each lesion can significantly alleviate the level of uncertainty in the measurement of thyroid uptake activity for each patient.

  12. (131)I activity quantification of gamma camera planar images.

    PubMed

    Barquero, Raquel; Garcia, Hugo P; Incio, Monica G; Minguez, Pablo; Cardenas, Alexander; Martínez, Daniel; Lassmann, Michael

    2017-02-07

    A procedure to estimate the activity in target tissues in patients during the therapeutic administration of (131)I radiopharmaceutical treatment for thyroid conditions (hyperthyroidism and differentiated thyroid cancer) using a gamma camera (GC) with a high energy (HE) collimator, is proposed. Planar images are acquired for lesions of different sizes r, and at different distances d, in two HE GC systems. Defining a region of interest (ROI) on the image of size r, total counts n g are measured. Sensitivity S (cps MBq(-1)) in each acquisition is estimated as the product of the geometric G and the intrinsic efficiency η 0. The mean fluence of 364 keV photons arriving at the ROI per disintegration G, is calculated with the MCNPX code, simulating the entire GC and the HE collimator. Intrinsic efficiency η 0 is estimated from a calibration measurement of a plane reference source of (131)I in air. Values of G and S for two GC systems-Philips Skylight and Siemens e-cam-are calculated. The total range of possible sensitivity values in thyroidal imaging in the e-cam and skylight GC measure from 7 cps MBq(-1) to 35 cps MBq(-1), and from 6 cps MBq(-1) to 29 cps MBq(-1), respectively. These sensitivity values have been verified with the SIMIND code, with good agreement between them. The results have been validated with experimental measurements in air, and in a medium with scatter and attenuation. The counts in the ROI can be produced by direct, scatter and penetration photons. The fluence value for direct photons is constant for any r and d values, but scatter and penetration photons show different values related to specific r and d values, resulting in the large sensitivity differences found. The sensitivity in thyroidal GC planar imaging is strongly dependent on uptake size, and distance from the GC. An individual value for the acquisition sensitivity of each lesion can significantly alleviate the level of uncertainty in the measurement of thyroid uptake activity for

  13. Multispectral illumination and image processing techniques for active millimeter-wave concealed object detection.

    PubMed

    Zhang, Lixiao; Stiens, Johan; Elhawil, Amna; Vounckx, Roger

    2008-12-01

    Active millimeter-wave imaging systems for concealed object detection offer the possibility of much higher image contrast than passive systems, especially in indoor applications. By studying active millimeter-wave images of different test objects derived in the W band, we show that multispectral illumination is critical to the detectability of targets. We also propose to use image change detection techniques, including image differencing, normalized difference vegetation index, and principle component analysis to process the multispectral millimeter-wave images. The results demonstrate that multispectral illumination can significantly reveal the object features hidden by image artifacts and improve the appearance of the objects.

  14. Comparison of different active polarimetric imaging modes for target detection in outdoor environment.

    PubMed

    Vannier, Nicolas; Goudail, François; Plassart, Corentin; Boffety, Matthieu; Feneyrou, Patrick; Leviandier, Luc; Galland, Frédéric; Bertaux, Nicolas

    2016-04-10

    We address the detection of manufactured objects in different types of environments with active polarimetric imaging. Using an original, fully adaptive imager, we compare several imaging modes having different numbers of polarimetric degrees of freedom. We demonstrate the efficiency of active polarimetric imaging for decamouflage and hazardous object detection, and underline the characteristics that a polarimetric imager aimed at this type of application should possess. We show that in most encountered scenarios the Mueller matrices are nearly diagonal, and sufficient detection performance can be obtained with simple polarimetric imaging systems having reduced degrees of freedom. Moreover, intensity normalization of images is of paramount importance to better reveal polarimetric contrast.

  15. The left bundle branch block revised with novel imaging modalities

    PubMed Central

    van Dijk, J.; Mannaerts, H.F.J.; Germans, T.; Hauer, H.A.; Knaapen, P.; Visser, C.A.; Kamp, O.

    2006-01-01

    Left bundle branch block (LBBB) is related to abnormal cardiac conduction and mechanical asynchrony and is associated with hypertension and coronary artery disease. Improved evaluation of left ventricular (LV) mechanical asynchrony is needed, because of the increasing number of patients with LBBB and heart failure. In this paper, we describe tissue Doppler imaging (TDI), strain (rate) imaging and tissue tracking in LBBB patients. A variety of patterns of mechanical activation can be observed in LBBB patients. A recent development, referred to as tissue synchronisation imaging, colour codes TDI time-to-peak systolic velocities of segments and displays mechanical asynchrony. Furthermore, real-time 3D echocardiography provides new regional information about mechanical asynchrony. Contained in an LV model and projected on a bull's eye plot, this modality helps to display the spatial distribution of mechanical asynchrony. Finally, segmental time-to-peak circumferential strain curves, produced by cardiac magnetic resonance imaging, provide additional quantification of LV mechanical asynchrony. Effects of LBBB on regional and global cardiac function are impressive, myocardial involvement seems to play a role and with the help of these novel imaging modalities, new insights continue to develop. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5Figure 6Figure 7 PMID:25696572

  16. Range-gated intensified spectrographic imager: an instrument for active hyperspectral imaging

    NASA Astrophysics Data System (ADS)

    Simard, Jean-Robert; Mathieu, Pierre; Fournier, Georges R.; Larochelle, Vincent; Babey, Stephen K.

    2000-09-01

    Hyperspectral imaging has demonstrated impressive capabilities in airborne surveys, particularly for mineral and biomass characterizations. Based on this success, it is believed that other applications like search and rescue operations, and detection/identification of various ground military targets could greatly benefit from this technology. The strength of hyperspectral imaging comes from the access to another dimension of information: the spectral content of the detected return signal for each spatial pixel. In the case of conventional hyperspectral imaging, the return signal depicts the spectral reflectance of the day irradiance from the scene within the field of view of each pixel. However, by inserting a range-gated intensifier into a hyperspectral camera and by combining the camera with selected pulsed lasers, it becomes possible to relate the returned spectral information to specific light/matter interactions like induced fluorescence. This new technique may be referred to as 'active hyperspectral imaging.' Among its advantages, this approach is independent of the ambient lighting conditions and can be customized in excitation wavelengths. Moreover, by using a range-gated intensified camera, it is possible to survey limited area with a significant increase in signal-to-noise ratio. A camera of this type has been built by our group in collaboration with private industry and is described in this paper. The internal design of the camera is discussed, new issues concerning the calibration of the camera are depicted and a model based on signal-to-noise ratio analysis is presented. From the fluorescent characteristics of surrogate land mines measured in the laboratory, this model is used to predict the capabilities of detecting surface-laid mines from an aerial platform based scenario.

  17. 16 CFR Figure 3 to Part 1508 - Figure 3 to Part 1508

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 2 2014-01-01 2014-01-01 false Figure 3 to Part 1508 3 Figure 3 to Part 1508 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS FIREWORKS DEVICES Multiple-tube fireworks devices. Pt. 1508, Fig. 3 Figure 3 to Part 1508...

  18. 16 CFR Figure 3 to Part 1509 - Figure 3 to Part 1509

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Figure 3 to Part 1509 3 Figure 3 to Part 1509 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS REQUIREMENTS FOR NON-FULL-SIZE BABY CRIBS Pt. 1509, Fig. 3 Figure 3 to Part 1509 EC03OC91.066...

  19. 16 CFR Figure 3 to Part 1508 - Figure 3 to Part 1508

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Figure 3 to Part 1508 3 Figure 3 to Part 1508 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS REQUIREMENTS FOR FULL-SIZE BABY CRIBS Pt. 1508, Fig. 3 Figure 3 to Part 1508 EC03OC91.063...

  20. 16 CFR Figure 1 to Part 1509 - Figure 1 to Part 1509

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Figure 1 to Part 1509 1 Figure 1 to Part 1509 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS REQUIREMENTS FOR NON-FULL-SIZE BABY CRIBS Pt. 1509, Fig. 1 Figure 1 to Part 1509 EC03OC91.064...

  1. 16 CFR Figure 1 to Part 1509 - Figure 1 to Part 1509

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Figure 1 to Part 1509 1 Figure 1 to Part 1509 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS REQUIREMENTS FOR NON-FULL-SIZE BABY CRIBS Pt. 1509, Fig. 1 Figure 1 to Part 1509 EC03OC91.064...

  2. 16 CFR Figure 3 to Part 1508 - Figure 3 to Part 1508

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Figure 3 to Part 1508 3 Figure 3 to Part 1508 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS REQUIREMENTS FOR FULL-SIZE BABY CRIBS Pt. 1508, Fig. 3 Figure 3 to Part 1508 EC03OC91.063...

  3. 16 CFR Figure 3 to Part 1509 - Figure 3 to Part 1509

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Figure 3 to Part 1509 3 Figure 3 to Part 1509 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS REQUIREMENTS FOR NON-FULL-SIZE BABY CRIBS Pt. 1509, Fig. 3 Figure 3 to Part 1509 EC03OC91.066...

  4. 16 CFR Figure 3 to Part 1508 - Figure 3 to Part 1508

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Figure 3 to Part 1508 3 Figure 3 to Part 1508 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS FIREWORKS DEVICES Multiple-tube fireworks devices. Pt. 1508, Fig. 3 Figure 3 to Part 1508...

  5. 16 CFR Figure 3 to Part 1508 - Figure 3 to Part 1508

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Figure 3 to Part 1508 3 Figure 3 to Part 1508 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS FIREWORKS DEVICES Multiple-tube fireworks devices. Pt. 1508, Fig. 3 Figure 3 to Part 1508...

  6. Novel method for high accuracy figure measurement of optical flat

    NASA Astrophysics Data System (ADS)

    E, Kewei; Li, Dahai; Yang, Lijie; Guo, Guangrao; Li, Mengyang; Wang, Xuemin; Zhang, Tao; Xiong, Zhao

    2017-01-01

    Phase Measuring Deflectometry (PMD) is a non-contact, high dynamic-range and full-field metrology which becomes a serious competitor to interferometry. However, the accuracy of deflectometry metrology is strongly influenced by the level of the calibrations, including test geometry, imaging pin-hole camera and digital display. In this paper, we propose a novel method that can measure optical flat surface figure to a high accuracy. We first calibrate the camera using a checker pattern shown on a LCD display at six different orientations, and the last orientation is aligned at the same position as the test optical flat. By using this method, lens distortions and the mapping relationship between the CCD pixels and the subaperture coordinates on the test optical flat can be determined at the same time. To further reduce the influence of the calibration errors on measurements, a reference optical flat with a high quality surface is measured, and then the system errors in our PMD setup can be eliminated by subtracting the figure of the reference flat from the figure of the test flat. Although any expensive coordinates measuring machine, such as laser tracker and coordinates measuring machine are not applied in our measurement, our experimental results of optical flat figure from low to high order aberrations still show a good agreement with that from the Fizeau interferometer.

  7. Nerves on magnetic resonance imaging.

    PubMed Central

    Collins, J. D.; Shaver, M. L.; Batra, P.; Brown, K.

    1989-01-01

    Nerves are often visualized on magnetic resonance imaging (MRI) studies of the soft tissues on the chest and shoulder girdle. To learn the reasons for the contrast between the nerves and adjacent tissues, the authors obtained a fresh specimen containing part of the brachial plexus nerves from the left axilla and compared MRI with x-ray projections and photomicrographs of histologic sections. The results suggest that the high signals from the nerves stand out in contrast to the low signals from their rich vascular supply. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6A Figure 6B Figure 7 PMID:2733051

  8. Analysis of the Context Integration Mechanisms Underlying Figure-Ground Organization in the Visual Cortex

    PubMed Central

    Zhang, Nan R.; von der Heydt, Rüdiger

    2010-01-01

    Most neurons in visual cortex respond to contrast borders and are orientation selective, and some are also selective for which side of a border is figure and which side is ground (‘border ownership coding’). These neurons are influenced by the image context far beyond the classical receptive field (CRF), and as early as 25ms after the onset of activity in the cortex. The nature of the fast context integration mechanism is not well understood. What parts of a figure contribute to the context effect? What is the structure of the ‘extra-classical surround’? Is the context information propagated through horizontal fibers within cortex, or through reciprocal connections via higher-level areas? To address these questions we studied border ownership modulation with fragmented figures. Neurons were recorded in areas V1 and V2 of macaca mulatta under behaviorally induced fixation. Test figures were fragmented rectangles. While one edge was centered on the CRF, the presence of the fragments outside the CRF was varied. The surround fragments produced facilitation on the preferred border ownership side as well as suppression on the non-preferred side, with about 80% of the locations contributing on average. Fragments far from the CRF influenced the responses even in the absence of fragments closer to the CRF, and without the extra delay that would incur from propagation through horizontal fibers. Three principally different models are discussed. The results support a model in which the antagonistic surround influences are produced by reentrant signals from a higher-level area. PMID:20463212

  9. Using the SDO Atmospheric Imaging Assembly to Study Solar Activity

    NASA Astrophysics Data System (ADS)

    Lemen, James

    2014-01-01

    The Atmospheric Imaging Assembly (AIA) is one of the instruments on board NASA’s flagship Solar Dynamics Observatory (SDO) mission that was launched in February 2010. AIA achieves 1.5 arcsec spatial resolution of the entire solar corona with 12-second temporal resolution in seven extreme ultraviolet (EUV) band passes centered on specific lines: Fe XVIII (94 Å), Fe VIII, XXI (131 Å), Fe IX (171 Å), Fe XII, XXIV (193 Å), Fe XIV (211 Å), He II (304 Å) and Fe XVI (335 Å) one band pass observes C IV (near 1600 Å). In the past 3 years AIA has produced over 77M images and 1,200 Tbytes of data that have challenged and clarified our understanding of the solar corona, specifically how the solar magnetic field drives coronal evolution on various scales. Multi-temperature, low-noise, full-Sun observations have captured solar eruptions and flares, coronal field oscillations (in loops and filaments), fast-mode waves (up to 2,000 km/s), plasma instabilities, and a rare view of comet interactions with the corona. Comparison with data from other instruments, such as SDO EUV Variability Experiment (EVE), and with numerical models, provides the ability to develop a comprehensive understanding of solar activity and evolution. And the comparison of the information-rich spatial content of the AIA observations with EVE spectra is instructive for similar studies of stellar targets. The NASA heliophysics open-data policy enables wide-scale participation by the international community. As the time base of AIA observations and magnetic data obtained from the companion SDO Helioseismic and Magnetic Imager (HMI) increases to a good fraction of the solar dynamo cycle time scale, we anticipate that the value of the SDO data will be similarly magnified. We present highlights that have been gleaned from this already exceptional mission. http://sdowww.lmsal.com

  10. High voltage protection in active matrix flat-panel imagers

    NASA Astrophysics Data System (ADS)

    Lehnert, Joerg; Zhao, Wei

    2006-03-01

    Various direct and indirect active matrix flat-panel imagers (AMFPI) are being investigated for x-ray imaging. In both direct AMFPI and indirect AMFPI with avalanche gain, a bias potential up to several thousand volts is required to operate the photoconductor. Under the condition of a large amount of radiation exposure between subsequent readout, a potential >80 V could appear across the amorphous silicon (a-Si) thin film transistor (TFT) and cause permanent damage. The purpose of this paper is to investigate a simple pixel design for high voltage protection. The pixel electrode acts as an additional gate for the top channel of an a-Si TFT to drain excess image charge from the pixel electrode until an equilibrium is reached where the TFT channel current equals the detector signal current at a predetermined safe maximum value V Pmax for the pixel potential. This "dual-gate" TFT structure without additional protective device simplifies the TFT array design and improves yield. However special care is required to understand the characteristics of both the top and the bottom gates to ensure sufficient detector dynamic range as well as reliable high voltage protection. A physical model for dual-gate a-Si TFTs was developed and device parameters were determined by fitting the model to measured characteristics from a dual-gate TFT array. Our results showed that compared to the bottom (normal) gate, the protective gate has a shallower transfer characteristics (i.e. channel current as a function of gate voltage) due to a higher density of states in the top interface. Nevertheless it provides adequate protection of the TFT with V Pmax of ~40 V for typical radiographic exposures.

  11. A fluorescent reporter of caspase activity for live imaging

    PubMed Central

    Bardet, Pierre-Luc; Kolahgar, Golnar; Mynett, Anita; Miguel-Aliaga, Irene; Briscoe, James; Meier, Pascal; Vincent, Jean-Paul

    2008-01-01

    There is a growing interest in the mechanisms that control the apoptosis cascade during development and adult life. To investigate the regulatory events that trigger apoptosis in whole tissues, we have devised a genetically encoded caspase sensor that can be detected in live and fixed tissue by standard confocal microscopy. The sensor comprises two fluorophores, mRFP, monomeric red fluorescent protein (mRFP) and enhanced green fluorescent protein (eGFP), that are linked by an efficient and specific caspase-sensitive site. Upon caspase activation, the sensor is cleaved and eGFP translocates to the nucleus, leaving mRFP at membranes. This is detected before other markers of apoptosis, including anti–cleaved caspase 3 immunoreactivity. Moreover, the sensor does not perturb normal developmental apoptosis and is specific, as cleavage does not occur in Drosophila embryos that are unable to activate the apoptotic cascade. Importantly, dying cells can be recognized in live embryos, thus opening the way for in vivo imaging. As expected from the high conservation of caspases, it is also cleaved in dying cells of chick embryos. It is therefore likely to be generally useful to track the spatiotemporal pattern of caspase activity in a variety of species. PMID:18779587

  12. Magnetic Resonance Imaging of the Central Nervous System—An Update

    PubMed Central

    Brant-Zawadzki, Michael; Norman, David; Newton, T. Hans; Kucharczyk, Walter

    1985-01-01

    Magnetic resonance imaging has developed rapidly and now has superior ability to detect and to characterize disease in the central nervous system without any significant biologic hazard. It is becoming the screening method of choice in the diagnosis of neoplasm, ischemia, hemorrhage, infection and degenerative and demyelinating diseases involving the central nervous system. ImagesFigure 1.Figure 2.Figure 3.Figure 4.Figure 5.Figure 6.Figure 7.Figure 8.Figure 9. PMID:3976220

  13. Advanced figure sensor operations and maintenance manual

    NASA Technical Reports Server (NTRS)

    Robertson, H. J.

    1972-01-01

    This manual contains procedures for installing, operating, and maintaining the optical figure sensor and its associated electronic controls. The optical figure sensor, a system of integrated components, comprises: (1) a phase measuring modified interferometer employing a single frequency 6328 A laser, and a Vidissector; (2) a two-axis automatic thermal compensation control mount; (3) a five degree of freedom manual adjustment stand; and (4) a control console. This instrument provides real time output data of optical figure errors for spherical mirrors, and is also capable of measuring aspherical mirrors if a null corrector is added.

  14. Active vision and image/video understanding with decision structures based on the network-symbolic models

    NASA Astrophysics Data System (ADS)

    Kuvich, Gary

    2003-08-01

    Vision is a part of a larger information system that converts visual information into knowledge structures. These structures drive vision process, resolve ambiguity and uncertainty via feedback projections, and provide image understanding that is an interpretation of visual information in terms of such knowledge models. The ability of human brain to emulate knowledge structures in the form of networks-symbolic models is found. And that means an important shift of paradigm in our knowledge about brain from neural networks to "cortical software". Symbols, predicates and grammars naturally emerge in such active multilevel hierarchical networks, and logic is simply a way of restructuring such models. Brain analyzes an image as a graph-type decision structure created via multilevel hierarchical compression of visual information. Mid-level vision processes like clustering, perceptual grouping, separation of figure from ground, are special kinds of graph/network transformations. They convert low-level image structure into the set of more abstract ones, which represent objects and visual scene, making them easy for analysis by higher-level knowledge structures. Higher-level vision phenomena are results of such analysis. Composition of network-symbolic models works similar to frames and agents, combines learning, classification, analogy together with higher-level model-based reasoning into a single framework. Such models do not require supercomputers. Based on such principles, and using methods of Computational intelligence, an Image Understanding system can convert images into the network-symbolic knowledge models, and effectively resolve uncertainty and ambiguity, providing unifying representation for perception and cognition. That allows creating new intelligent computer vision systems for robotic and defense industries.

  15. A case of figurate urticaria by etanercept

    PubMed Central

    Sessa, Maurizio; Sullo, Maria Giuseppa; Mascolo, Annamaria; Cimmaruta, Daniela; Romano, Francesca; Puca, Rosa Valentina; Capuano, Annalisa; Rossi, Francesco; Schiavo, Ada Lo

    2016-01-01

    Etanercept is a competitive inhibitor of tumor necrosis factor-alpha (TNF-α) a polypeptide hormone, involved in the development of the immune system, in host defense and immune surveillance. Even if the etanercept mechanism of action is not completely understood, it is supposed that it negatively modulates biological responses mediated by molecules (cytokines, adhesion molecules, or proteinases) induced or regulated by TNF. For this reason, it is widely used in the treatment of immunologicals diseases, such as rheumatoid and psoriatic arthritis, polyarticular juvenile idiopathic active, ankylosing spondylitis, and plaque psoriasis. Etanercept has a good tolerability profile. Adverse events related to skin are rare, arising usually in about 5% of patients treated with anti-TNF α. In this scenario, we describe a case of figurate urticaria arose after the re-administration of etanercept in a patient affected by psoriasis and hepatitis B. A 65-year-old man, affected by psoriasis, was hospitalized in September 2014 to the Regional Center for the treatment of psoriasis and Biological Drugs of Second University of Naples for progressive extension of psoriatic skin lesions. The laboratory analysis detected positivity for hepatitis B virus (HBV) antigens. For this reason, it was administered to him lamivudine 100 mg/die about 30 days before to start etanercept treatment. The etanercept therapy has resulted in a progressive improving of skin manifestations, and the patient decided individually to stop the therapy. Afterwards, for worsening of the psoriatic lesions, he was again hospitalized and treated with the same therapeutic schedule (lamivudine followed by etanercept). Ten days after the start of therapy, the patient showed the onset of urticarial rash. Due to this, the treatment with lamivudine and etanercept was suspended and the patient's clinical conditions improved. It is probably that immunological disorders due to etanercept therapy and HBV infection could

  16. The image and advocacy of public health in American caricature and cartoons from 1860 to 1900.

    PubMed Central

    Hansen, B

    1997-01-01

    The decades just before and after the founding of the American Public Health Association in 1872 saw an efflorescence of political cartooning and caricature in national-circulation weeklies. Part of the political and social critique that cartoonists and their editors provided the public focused on needs or opportunities for preventing illness and accidents. This paper presents a small selection of editorial cartoons that agitated in support of public health activities over 4 decades. The goals are to illustrate several concerns that rose to national prominence in that era, to examine the kinds of imagery that newspapers and magazine editors offered their readers, and to observe how frequently the public was encouraged to see politicians and commercial interests as responsible for preventable health problems. This discussion focuses exclusively on propagandistic images, leaving aside the reportorial depictions of events in the news and the neutral illustrations of methods and machines in scientific and technical publications. Images FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 5 FIGURE 6 FIGURE 7 FIGURE 8 FIGURE 9 FIGURE 10 FIGURE 11 PMID:9366637

  17. Past to Present: Undergrowth with Two Figures

    ERIC Educational Resources Information Center

    School Arts: The Art Education Magazine for Teachers, 2004

    2004-01-01

    This brief article describes the historical, cultural, and artistic elements of Vincent van Gogh's oil on canvas "Undergrowth with Two Figures" of 1980. The article concludes with questions for students to consider in relation to these aspects of the painting.

  18. Rhetoric Denuded and Redressed: Figs and Figures.

    ERIC Educational Resources Information Center

    Poulakos, John; Whitson, Steve

    1995-01-01

    Replies to an article in this issue that responds to an earlier article by these authors. Replies aesthetically in aphorisms, subsuming philosophical argument within a vortex of figuration and thus troping the knowledge drive while privileging "doxa" over "episteme." (SR)

  19. A feedback model of figure-ground assignment.

    PubMed

    Domijan, Drazen; Setić, Mia

    2008-05-30

    A computational model is proposed in order to explain how bottom-up and top-down signals are combined into a unified perception of figure and background. The model is based on the interaction between the ventral and the dorsal stream. The dorsal stream computes saliency based on boundary signals provided by the simple and the complex cortical cells. Output from the dorsal stream is projected to the surface network which serves as a blackboard on which the surface representation is formed. The surface network is a recurrent network which segregates different surfaces by assigning different firing rates to them. The figure is labeled by the maximal firing rate. Computer simulations showed that the model correctly assigns figural status to the surface with a smaller size, a greater contrast, convexity, surroundedness, horizontal-vertical orientation and a higher spatial frequency content. The simple gradient of activity in the dorsal stream enables the simulation of the new principles of the lower region and the top-bottom polarity. The model also explains how the exogenous attention and the endogenous attention may reverse the figural assignment. Due to the local excitation in the surface network, neural activity at the cued region will spread over the whole surface representation. Therefore, the model implements the object-based attentional selection.

  20. Using the One Degree Imager to Study Active Asteroids

    NASA Astrophysics Data System (ADS)

    Brunker, Samantha; Rajagopal, Jayadev; Ridgway, Susan E.

    2015-01-01

    Active asteroids are asteroids that eject material, which can be caused by several different mechanisms that act on the asteroid, such as collisions, rotational instability, or radiation pressure. We study these asteroids in order to better understand these ejection mechanisms, and gauge their contribution to the zodiacal dust in the Solar System. For this project at the NOAO/KPNO REU program, we chose to focus on two specific asteroids, P/2010 A2 and 300160. Both asteroids were observed with the partial One Degree Imager on the WIYN 3.5 meter telescope on Kitt Peak. P/2010 A2 has an impressive debris tail made up of ejected dust that stretches for over a million kilometers. The wide field of pODI allowed us to construct a surface brightness profile for almost the entire extent of the tail. From this we can investigate the ejection mechanisms that caused the tail to form, and estimate the dust mass. For 300163 we did follow up observations to search for any current activity. We did not identify any trace of nebulosity in our data which indicate that the previously seen nebulosity was part of a transient event. This gives us clues about the possible ejection mechanisms acting on 300163.S. Brunker was supported by the NOAO/KPNO Research Experiences for Undergraduates Program which is funded by the National Science Foundation Research Experiences for Undergraduates Program (AST-1262829).

  1. GRID based Thermal Images Processing for volcanic activity monitoring

    NASA Astrophysics Data System (ADS)

    Mangiagli, S.; Coco, S.; Drago, L.; Laudani, A.,; Lodato, L.; Pollicino, G.; Torrisi, O.

    2009-04-01

    Since 2001, the Catania Section of the National Institute of Geophysics and Volcanology (INGV) has been running the video stations recording the volcanic activity of Mount Etna, Stromboli and the Fossa Crater of Vulcano island. The video signals of 11 video cameras (seven operating in the visible band and four in infrared) are sent in real time to INGV Control Centre where they are visualized on monitors and archived on a dedicated NAS storage. The video surveillance of the Sicilian volcanoes, situated near to densely populated areas, helps the volcanologists providing the Civil Protection authorities with updates in real time on the on-going volcanic activity. In particular, five video cameras are operating on Mt. Etna and they record the volcano from the south and east sides 24 hours a day. During emergencies, mobile video stations may also be used to better film the most important phases of the activity. Single shots are published on the Catania Section intranet and internet websites. On June 2006 a A 40 thermal camera was installed in Vulcano La Fossa Crater. The location was in the internal and opposite crater flank (S1), 400 m distant from the fumarole field. The first two-year of data on temperature distribution frequency were recorded with this new methodology of acquisition, and automatically elaborated by software at INGV Catania Section. In fact a dedicated software developed in IDL, denominated Volcano Thermo Analysis (VTA), was appositely developed in order to extract a set of important features, able to characterize with a good approssimation the volcanic activity. In particular the program first load and opportunely convert the thermal images, then according to the Region Of Interest (ROI) and the temperature ranges defined by the user provide to automatic spatial and statistic analysis. In addition the VTA is able to analysis all the temporal series of images available in order to achieve the time-event analysis and the dynamic of the volcanic

  2. Evolution of the Significant Figure Rules

    NASA Astrophysics Data System (ADS)

    Carter, Ashley R.

    2013-09-01

    Today, almost all introductory physics textbooks include standardized "rules" on how to find the number of significant figures in a calculated value. And yet, 30 years ago these rules were almost nonexistent. Whyhave we increased the role of significant figures in introductory classes, and should we continue this trend? A look back at the evolution of significant figures over the last 300 years, from Newton to Millikan to modern authors, sheds some light on their purpose moving forward. While there is much discussion for and against their use, especially in chemistry, a review of earlier versions of the rules suggests that we have lost some items of value, most notably, a significant figure rule for angles. In addition, we have lost the emphasis that the significant figure rules were designed to calculate an approximate (not exact) precision. Now that the significant figure rules are ingrained into our introductory physics sequence, we would be wise to reiterate that these are just general "rules of thumb."

  3. Ion beam figuring of small optical components

    NASA Astrophysics Data System (ADS)

    Drueding, Thomas W.; Fawcett, Steven C.; Wilson, Scott R.; Bifano, Thomas G.

    1995-12-01

    Ion beam figuring provides a highly deterministic method for the final precision figuring of optical components with advantages over conventional methods. The process involves bombarding a component with a stable beam of accelerated particles that selectively removes material from the surface. Figure corrections are achieved by rastering the fixed-current beam across the workplace at appropriate, time-varying velocities. Unlike conventional methods, ion figuring is a noncontact technique and thus avoids such problems as edge rolloff effects, tool wear, and force loading of the workpiece. This work is directed toward the development of the precision ion machining system at NASA's Marshall Space Flight Center. This system is designed for processing small (approximately equals 10-cm diam) optical components. Initial experiments were successful in figuring 8-cm-diam fused silica and chemical-vapor-deposited SiC samples. The experiments, procedures, and results of figuring the sample workpieces to shallow spherical, parabolic (concave and convex), and non-axially-symmetric shapes are discussed. Several difficulties and limitations encountered with the current system are discussed. The use of a 1-cm aperture for making finer corrections on optical components is also reported.

  4. Research on the system scheme and experiment for the active laser polarization imaging

    NASA Astrophysics Data System (ADS)

    Fu, Qiang; Duan, Jin; Zhao, Rui; Li, Zheng; Zhang, Su; Zhan, Juntong; Zhu, Yong; Jiang, Hui-Lin

    2015-10-01

    The polarization imaging detection technology increased the polarization information on the basis of the intensity imaging, which is extensive application in the military and civil and other fields. The research present and development trend of polarization imaging detection technology was introduce, the system scheme of the active polarization imaging detection was put forward, and the key technologies such as the polarization information detection, optical system design, polarization radiation calibration and image fusion approach was analyzed. On this basis, detection system by existing equipment of laboratory was set up, and on the different materials such as wood, metal, plastic and goal was detected by polarization imaging to realize the active polarization imaging detection. The results show that image contrast of the metal and man-made objects is higher, the polarization effect is better, which provided the basis on the better performance of the polarization imaging instruments.

  5. Linking brain to behavior for the visual perception of figures and objects.

    PubMed

    Fesi, Jeremy D; Mendola, Janine D

    2013-11-01

    The dissociation of a figure from its background is an essential feat of visual perception, as it allows us to detect, recognize, and interact with shapes and objects in our environment. In order to understand how the human brain gives rise to the perception of figures, we here review experiments that explore the links between activity in visual cortex and performance of perceptual tasks related to figure perception. We organize our review according to a proposed model that attempts to contextualize figure processing within the more general framework of object processing in the brain. Overall, the current literature provides us with individual linking hypotheses as to cortical regions that are necessary for particular tasks related to figure perception. Attempts to reach a more complete understanding of how the brain instantiates figure and object perception, however, will have to consider the temporal interaction between the many regions involved, the details of which may vary widely across different tasks.

  6. Wet-Etch Figuring Optical Figuring by Controlled Application of Liquid Etchant

    SciTech Connect

    Britten, J

    2001-02-13

    WET-ETCH FIGURING (WEF) is an automated method of precisely figuring optical materials by the controlled application of aqueous etchant solution. This technology uses surface-tension-gradient-driven flow to confine and stabilize a wetted zone of an etchant solution or other aqueous processing fluid on the surface of an object. This wetted zone can be translated on the surface in a computer-controlled fashion for precise spatial control of the surface reactions occurring (e.g. chemical etching). WEF is particularly suitable for figuring very thin optical materials because it applies no thermal or mechanical stress to the material. Also, because the process is stress-free the workpiece can be monitored during figuring using interferometric metrology, and the measurements obtained can be used to control the figuring process in real-time--something that cannot be done with traditional figuring methods.

  7. Optical imaging of neural activity: from neuron to brain

    NASA Astrophysics Data System (ADS)

    Luo, Qingming; Zeng, Shaoqun; Gong, Hui

    2003-12-01

    This paper introduces the optical imaging approaches at three levels in cognitive neuroscience in the Key Laboratory of Biomedical Photonics of Ministry of Education of China. In molecular and cellular level, the advances in microscopy, molecular optical marker, and sample preparations have made possible studies that characterize the form and function of neurons in unprecedented detail. The development of two-photon excitation has enabled fluorescent imaging of small structures in the midst of highly scattering media with little photodamage. The combination of MPE and multi-electrode array provides a powerful approach for neuronal networks imaging. Intrinsic signal imaging (ISI) and laser speckle imaging (LSI) are effective approaches for intrinsic signal imaging at a given cortical site. No alternative imaging technique for the visualization of functional organization in the living brain provides a comparable spatial resolution. It is this level of resolution that reveals where processing is performed - a necessary step for the understanding of the neural code at the population level. Completely noninvasive optical imaging through the intact human skull, such as functional near infrared imaging may provide an imaging tool offering both the spatial and the temporal resolutions required to expand our knowledge of the principles underlying the remarkable performance of the human cerebral cortex.

  8. Figure-ground processing during fixational saccades in V1: indication for higher-order stability.

    PubMed

    Gilad, Ariel; Pesoa, Yair; Ayzenshtat, Inbal; Slovin, Hamutal

    2014-02-26

    In a typical visual scene we continuously perceive a "figure" that is segregated from the surrounding "background" despite ongoing microsaccades and small saccades that are performed when attempting fixation (fixational saccades [FSs]). Previously reported neuronal correlates of figure-ground (FG) segregation in the primary visual cortex (V1) showed enhanced activity in the "figure" along with suppressed activity in the noisy "background." However, it is unknown how this FG modulation in V1 is affected by FSs. To investigate this question, we trained two monkeys to detect a contour embedded in a noisy background while simultaneously imaging V1 using voltage-sensitive dyes. During stimulus presentation, the monkeys typically performed 1-3 FSs, which displaced the contour over the retina. Using eye position and a 2D analytical model to map the stimulus onto V1, we were able to compute FG modulation before and after each FS. On the spatial cortical scale, we found that, after each FS, FG modulation follows the stimulus retinal displacement and "hops" within the V1 retinotopic map, suggesting visual instability. On the temporal scale, FG modulation is initiated in the new retinotopic position before it disappeared from the old retinotopic position. Moreover, the FG modulation developed faster after an FS, compared with after stimulus onset, which may contribute to visual stability of FG segregation, along the timeline of stimulus presentation. Therefore, despite spatial discontinuity of FG modulation in V1, the higher-order stability of FG modulation along time may enable our stable and continuous perception.

  9. Imaging of influenza virus sialidase activity in living cells.

    PubMed

    Kurebayashi, Yuuki; Takahashi, Tadanobu; Otsubo, Tadamune; Ikeda, Kiyoshi; Takahashi, Shunsaku; Takano, Maiko; Agarikuchi, Takashi; Sato, Tsubasa; Matsuda, Yukino; Minami, Akira; Kanazawa, Hiroaki; Uchida, Yuko; Saito, Takehiko; Kawaoka, Yoshihiro; Yamada, Toshihiro; Kawamori, Fumihiko; Thomson, Robin; von Itzstein, Mark; Suzuki, Takashi

    2014-05-02

    Influenza virus is rich in variation and mutations. It would be very convenient for virus detection and isolation to histochemically detect viral infection regardless of variation and mutations. Here, we established a histochemical imaging assay for influenza virus sialidase activity in living cells by using a new fluorescent sialidase substrate, 2-(benzothiazol-2-yl)-4-bromophenyl 5-acetamido-3,5-dideoxy-α-D-glycero-D-galacto-2-nonulopyranosidonic acid (BTP3-Neu5Ac). The BTP3-Neu5Ac assay histochemically visualized influenza virus-infected cells regardless of viral hosts and subtypes. Influenza virus neuraminidase-expressed cells, viral focus formation, and virus-infected locations in mice lung tissues were easily, rapidly, and sensitively detected by the BTP3-Neu5Ac assay. Histochemical visualization with the BTP3-Neu5Ac assay is extremely useful for detection of influenza viruses without the need for fixation or a specific antibody. This novel assay should greatly improve the efficiency of detection, titration, and isolation of influenza viruses and might contribute to research on viral sialidase.

  10. Body image, BMI, and physical activity in girls and boys aged 14-16 years.

    PubMed

    Kantanista, Adam; Osiński, Wiesław; Borowiec, Joanna; Tomczak, Maciej; Król-Zielińska, Magdalena

    2015-09-01

    The aim of this study was to investigate the relationship between body image, body mass index (BMI), and physical activity in adolescents. The study included 1702 girls and 1547 boys aged 14-16 years. Moderate-to-vigorous physical activity (MVPA) was evaluated by the Physical Activity Screening Measure. Body image was assessed using the Feelings and Attitudes Towards the Body Scale, and participants' BMI was determined based on measured height and weight. Compared to boys, girls reported more negative body image (p<.05). The results of the three-way hierarchical regression revealed that body image was a statistically significant positive predictor of MVPA for adolescents, regardless of BMI. Additionally, body image was a stronger predictor of MVPA in boys than in girls. These findings suggest that body image, rather than BMI, is important in undertaking physical activity in adolescents and should be considered when preparing programs aimed at improving physical activity.

  11. Minimizing Uncertainty in Cryogenic Surface Figure Measurement

    NASA Technical Reports Server (NTRS)

    Blake, Peter; Mink, Ronald G.; Chambers, John; Robinson, F. David; Content, David; Davila, Pamela

    2005-01-01

    A new facility at the Goddard Space Flight Center is designed to measure with unusual accuracy the surface figure of mirrors at cryogenic temperatures down to 12 K. The facility is currently configured for spherical mirrors with a radius of curvature (ROC) of 600 mm, and apertures of about 150 mm or less. The goals of the current experiment were to 1) Obtain the best possible estimate of test mirror surface figure, S(x,y) at 87 K and 20 K; 2) Obtain the best estimate of the cryo-change, Delta (x,y): the change in surface figure between room temperature and the two cryo-temperatures; and 3) Determine the uncertainty of these measurements, using the definitions and guidelines of the ISO Guide to the Expression of Uncertainty in Measurement. A silicon mirror was tested, and the cry-change from room temperature to 20K was found to be 3.7 nm rms, with a standard uncertainty of 0.23 nm in the rms statistic. Both the cryo-change figure and the uncertainty are among the lowest such figures yet published. This report describes the facilities, experimental methods, and uncertainty analysis of the measurements.

  12. 50 CFR Figure 1 to Subpart E of... - Sitka Local Area Management Plan

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Sitka Local Area Management Plan 1 Figure 1 to Subpart E of Part 300 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS Pacific Halibut Fisheries Pt. 300, Subpt. E, Fig. 1 Figure 1 to Subpart E...

  13. 50 CFR Figure 1 to Subpart E of... - Sitka Local Area Management Plan

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 11 2013-10-01 2013-10-01 false Sitka Local Area Management Plan 1 Figure 1 to Subpart E of Part 300 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS Pacific Halibut Fisheries Pt. 300, Subpt. E, Fig. 1 Figure 1 to Subpart E...

  14. 50 CFR Figure 1 to Subpart E of... - Sitka Local Area Management Plan

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false Sitka Local Area Management Plan 1 Figure 1 to Subpart E of Part 300 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS Pacific Halibut Fisheries Pt. 300, Subpt. E, Fig. 1 Figure 1 to Subpart E...

  15. 50 CFR Figure 1 to Subpart E of... - Sitka Local Area Management Plan

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 11 2014-10-01 2014-10-01 false Sitka Local Area Management Plan 1 Figure 1 to Subpart E of Part 300 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS Pacific Halibut Fisheries Pt. 300, Subpt. E, Fig. 1 Figure 1 to Subpart E...

  16. Hybrid coded aperture and Compton imaging using an active mask

    NASA Astrophysics Data System (ADS)

    Schultz, L. J.; Wallace, M. S.; Galassi, M. C.; Hoover, A. S.; Mocko, M.; Palmer, D. M.; Tornga, S. R.; Kippen, R. M.; Hynes, M. V.; Toolin, M. J.; Harris, B.; McElroy, J. E.; Wakeford, D.; Lanza, R. C.; Horn, B. K. P.; Wehe, D. K.

    2009-09-01

    The trimodal imager (TMI) images gamma-ray sources from a mobile platform using both coded aperture (CA) and Compton imaging (CI) modalities. In this paper we will discuss development and performance of image reconstruction algorithms for the TMI. In order to develop algorithms in parallel with detector hardware we are using a GEANT4 [J. Allison, K. Amako, J. Apostolakis, H. Araujo, P.A. Dubois, M. Asai, G. Barrand, R. Capra, S. Chauvie, R. Chytracek, G. Cirrone, G. Cooperman, G. Cosmo, G. Cuttone, G. Daquino, et al., IEEE Trans. Nucl. Sci. NS-53 (1) (2006) 270] based simulation package to produce realistic data sets for code development. The simulation code incorporates detailed detector modeling, contributions from natural background radiation, and validation of simulation results against measured data. Maximum likelihood algorithms for both imaging methods are discussed, as well as a hybrid imaging algorithm wherein CA and CI information is fused to generate a higher fidelity reconstruction.

  17. Online glocal transfer for automatic figure-ground segmentation.

    PubMed

    Zou, Wenbin; Bai, Cong; Kpalma, Kidiyo; Ronsin, Joseph

    2014-05-01

    This paper addresses the problem of automatic figure-ground segmentation, which aims at automatically segmenting out all foreground objects from background. The underlying idea of this approach is to transfer segmentation masks of globally and locally (glocally) similar exemplars into the query image. For this purpose, we propose a novel high-level image representation method named as object-oriented descriptor. Using this descriptor, a set of exemplar images glocally similar to the query image is retrieved. Then, using over-segmented regions of these retrieved exemplars, a discriminative classifier is learned on-the-fly and subsequently used to predict foreground probability for the query image. Finally, the optimal segmentation is obtained by combining the online prediction with typical energy optimization of Markov random field. The proposed approach has been extensively evaluated on three datasets, including Pascal VOC 2010, VOC 2011 segmentation challenges, and iCoseg dataset. Experiments show that the proposed approach outperforms state-of-the-art methods and has the potential to segment large-scale images containing unknown objects, which never appear in the exemplar images.

  18. Active Millimeter-Wave and Sub-Millimeter-Wave Imaging for Security Applications

    SciTech Connect

    Sheen, David M.; McMakin, Douglas L.; Hall, Thomas E.

    2011-09-02

    Active imaging at millimeter and sub-millimeter wavelengths has been developed for security applications including concealed weapon detection. The physical properties that affect imaging performance are discussed along with a review of the current state-of-the-art and future potential for security imaging systems.

  19. In vivo stepwise multi-photon activation fluorescence imaging of melanin in human skin

    NASA Astrophysics Data System (ADS)

    Lai, Zhenhua; Gu, Zetong; Abbas, Saleh; Lowe, Jared; Sierra, Heidy; Rajadhyaksha, Milind; DiMarzio, Charles

    2014-03-01

    The stepwise multi-photon activated fluorescence (SMPAF) of melanin is a low cost and reliable method of detecting melanin because the activation and excitation can be a continuous-wave (CW) mode near infrared (NIR) laser. Our previous work has demonstrated the melanin SMPAF images in sepia melanin, mouse hair, and mouse skin. In this study, we show the feasibility of using SMPAF to detect melanin in vivo. in vivo melanin SMPAF images of normal skin and benign nevus are demonstrated. SMPAF images add specificity for melanin detection than MPFM images and CRM images. Melanin SMPAF is a promising technology to enable early detection of melanoma for dermatologists.

  20. Correspondence between some wave patterns and Lissajous figures

    NASA Astrophysics Data System (ADS)

    Górska, K. J.; Makowski, A. J.; Dembinski, S. T.

    2006-10-01

    We study the connections between some specially entangled stationary states and the classical periodic trajectories of two non-interacting oscillators. The latter are well-known Lissajous figures, which are shown to run precisely over the apogees of their corresponding probability distributions in the above states. We propose in this work a very simple criterion enabling us to obtain the best agreement between the quantum and the classical images. Finally, our results are successfully applied to the interpretation of some experimentally observed wave patterns.

  1. [Figures of anima in the Odyssey].

    PubMed

    Meneghello, Mauro

    2012-01-01

    Feminine characters in the Odyssey show different aspects of the archetype: Mother and Anima (C.G. Jung). From an Analytical Psychology perspective the encounters of Odysseus with goddesses: Circe, Calypso, Ino are looked at as different and successive stages of the hero's way into the inconscious, who shows himself in feminine figures, being masculine the consciousness of the hero. Nausicaa is a new, nearly-human figure of Anima who appears after the symbolic death of Odysseus and leads him to the royal couple Alcinous-Arete: in front of them all he finds his new, reborn, personality by creating and narrating his own myth.

  2. Metrics of Justice. A Sundial's Nomological Figuration.

    PubMed

    Behrmann, Carolin

    2015-01-01

    This paper examines a polyhedral dial from the British Museum made by the instrument maker Ulrich Schniep, and discusses the status of multifunctional scientific instruments. It discerns a multifaceted iconic meaning considering different dimensions such as scientific functionality (astronomy), the complex allegorical figure of Justice (iconography), and the representation of the sovereign (politics), the court and the Kunstkammer of Albrecht v of Bavaria. As a numen mixtum the figure of "Justicia" touches different fields that go far beyond pure astronomical measurement and represents the power of the ruler as well as the rules of economic justice.

  3. CMOS active pixel sensor type imaging system on a chip

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Nixon, Robert (Inventor)

    2011-01-01

    A single chip camera which includes an .[.intergrated.]. .Iadd.integrated .Iaddend.image acquisition portion and control portion and which has double sampling/noise reduction capabilities thereon. Part of the .[.intergrated.]. .Iadd.integrated .Iaddend.structure reduces the noise that is picked up during imaging.

  4. Images as Orienting Activity: Using Theory to Inform Classroom Practices

    ERIC Educational Resources Information Center

    Feryok, Anne; Pryde, Michael

    2012-01-01

    Conceptualizations of teacher knowledge have shifted to focusing on the role of experiential rather than theoretical knowledge. There are different approaches to this, but the idea of an image that guides practice is widespread. One approach to images that has not been frequently investigated in studies of second language teachers is through…

  5. Integrated imaging sensor systems with CMOS active pixel sensor technology

    NASA Technical Reports Server (NTRS)

    Yang, G.; Cunningham, T.; Ortiz, M.; Heynssens, J.; Sun, C.; Hancock, B.; Seshadri, S.; Wrigley, C.; McCarty, K.; Pain, B.

    2002-01-01

    This paper discusses common approaches to CMOS APS technology, as well as specific results on the five-wire programmable digital camera-on-a-chip developed at JPL. The paper also reports recent research in the design, operation, and performance of APS imagers for several imager applications.

  6. Ultrasound Activated Contrast Imaging for Prostate Cancer Detection

    DTIC Science & Technology

    2007-03-01

    Goldberg. Nonlinear imaging with a new contrast agent. Ultrasound Med Biol, vol. 29, pp. S97, 2003. R. J. Ro, F. Forsberg, M. Knauer, W. T. Shi, P. A ... Lewin , R. Bernardi. On the temperature and concentration dependency of excitation-enhanced imaging. Proc Biomed Eng Soc Ann Fall Meetg, abstract no

  7. Rapid volumetric temporal focusing multiphoton microscopy of neural activity: theory, image processing, and experimental realization

    NASA Astrophysics Data System (ADS)

    Dana, Hod; Marom, Anat; Kruger, Nimrod; Ellman, Aviv; Shoham, Shy

    2012-03-01

    The development of rapid volumetric imaging systems for functional multiphoton microscopy is essential for dynamical imaging of large-scale neuronal network activity. Here, we introduce a line-illuminating temporal-focusing microscope capable of rapid three-dimensional imaging at 10-20 volumes/sec, and study the system's characteristics both theoretically and experimentally. We demonstrate that our system is capable of functional volumetric calcium imaging of distributed neuronal activity patterns, and introduce a computational strategy for activity reconstruction in strongly scattering media.

  8. Active and passive imaging of clothes in the NIR and SWIR regions for reflectivity analysis.

    PubMed

    Grönwall, Christina; Steinvall, Ove; Göhler, Benjamin; Hamoir, Dominique

    2016-07-10

    We perform statistical analysis of data from active and passive imaging sensors in the near infrared (NIR) and short wavelength infrared (SWIR) wavelength bands. The data were obtained from measurements performed on clothing in a field campaign and in the laboratory. We show that reflectivity data from active imaging can be fitted to Gaussian functions, although earlier theory proposes gamma-gamma functions. We analyze the reflectivity data collected during the field campaign and compare that data with data obtained in the laboratory. We focus on the added value of active imaging when combined with passive imaging to distinguish different clothes for friend/foe identification.

  9. Teaching electron diffraction and imaging of macromolecules.

    PubMed Central

    Chiu, W; Schmid, M F; Prasad, B V

    1993-01-01

    Electron microscopic analysis can be used to determine the three-dimensional structures of macromolecules at resolutions ranging between 3 and 30 A. It differs from nuclear magnetic resonance spectroscopy or x-ray crystallography in that it allows an object's Coulomb potential functions to be determined directly from images and can be used to study relatively complex macromolecular assemblies in a crystalline or noncrystalline state. Electron imaging already has provided valuable structural information about various biological systems, including membrane proteins, protein-nucleic acid complexes, contractile and motile protein assemblies, viruses, and transport complexes for ions or macromolecules. This article, organized as a series of lectures, presents the biophysical principles of three-dimensional analysis of objects possessing different symmetries. Images FIGURE 3 FIGURE 4 FIGURE 5 FIGURE 6 FIGURE 7 FIGURE 9 FIGURE 10 FIGURE 11 FIGURE 12 FIGURE 13 FIGURE 17 FIGURE 18 PMID:8324196

  10. 50 CFR Figure 1 to Part 640 - Figure 1 to Part 640

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 10 2011-10-01 2011-10-01 false Figure 1 to Part 640 1 Figure 1 to Part 640 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE SPINY LOBSTER FISHERY OF THE GULF OF MEXICO AND SOUTH ATLANTIC Pt....

  11. 50 CFR Figure 1 to Part 640 - Figure 1 to Part 640

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 12 2012-10-01 2012-10-01 false Figure 1 to Part 640 1 Figure 1 to Part 640 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE SPINY LOBSTER FISHERY OF THE GULF OF MEXICO AND SOUTH ATLANTIC Pt....

  12. 50 CFR Figure 1 to Part 640 - Figure 1 to Part 640

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Figure 1 to Part 640 1 Figure 1 to Part 640 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE SPINY LOBSTER FISHERY OF THE GULF OF MEXICO AND SOUTH ATLANTIC Pt....

  13. Contextual effects on perceived contrast: figure-ground assignment and orientation contrast.

    PubMed

    Self, Matthew W; Mookhoek, Aart; Tjalma, Nienke; Roelfsema, Pieter R

    2015-02-02

    Figure-ground segregation is an important step in the path leading to object recognition. The visual system segregates objects ('figures') in the visual scene from their backgrounds ('ground'). Electrophysiological studies in awake-behaving monkeys have demonstrated that neurons in early visual areas increase their firing rate when responding to a figure compared to responding to the background. We hypothesized that similar changes in neural firing would take place in early visual areas of the human visual system, leading to changes in the perception of low-level visual features. In this study, we investigated whether contrast perception is affected by figure-ground assignment using stimuli similar to those in the electrophysiological studies in monkeys. We measured contrast discrimination thresholds and perceived contrast for Gabor probes placed on figures or the background and found that the perceived contrast of the probe was increased when it was placed on a figure. Furthermore, we tested how this effect compared with the well-known effect of orientation contrast on perceived contrast. We found that figure-ground assignment and orientation contrast produced changes in perceived contrast of a similar magnitude, and that they interacted. Our results demonstrate that figure-ground assignment influences perceived contrast, consistent with an effect of figure-ground assignment on activity in early visual areas of the human visual system.

  14. Specialized structure and metabolic activities of high endothelial venules in rat lymphatic tissues.

    PubMed Central

    Anderson, N D; Anderson, A O; Wyllie, R G

    1976-01-01

    Microscopic, histochemical and ultrastructural techniques were used to define characteristics of high endothelial venules (HEV) in rat lymphatic tissues. This endothelium contained acetyl esterase and acid hydrolase activities which were not altered by lymphocyte depletion. No immunoglobulins were detected on luminal surfaces of HEV by fluorescent antibody staining. Only minor structural differences were seen between HEV within lymph nodes and Peyer's patches. At both sites, high endothelial cells were linked together by macular junctional complexes and interlocking basal foot processes. Endothelial cell cytoplasm moulded about surfaces of lymphocytes migrating through the venular wall, and flocculant deposits of basement membrane formed over lymphocytes penetrating the basal lamina. The endothelium was ensheathed by three to five layers of overlapping reticular cell plates and connective tissue. Each plate was linked to the reticular meshwork of the node by collagen bundles and anchoring filaments which inserted into the plate's external limiting membrane. This permitted individual paltes to separate or approximate each other as tissue and intravascular pressure varied, and lymphocytes moved across the sheath by insinuating themselves into gaps between overlapping plates. This composite structure of the HEV wall appeared to facilitate lymphocyte entry into the node and minimized vascular leakge. Images Figures 11-13 Figures 1-4 Figure 5 Figure 6 Figure 7 Figure 8 Figures 9-10 Figures 14-15 Figure 16 Figures 17-20 Figure 22 Figure 23 Figure 24 PMID:1027726

  15. Curiosity's Mars Hand Lens Imager (MAHLI): Inital Observations and Activities

    NASA Technical Reports Server (NTRS)

    Edgett, K. S.; Yingst, R. A.; Minitti, M. E.; Robinson, M. L.; Kennedy, M. R.; Lipkaman, L. J.; Jensen, E. H.; Anderson, R. C.; Bean, K. M.; Beegle, L. W.; Carsten, J. L.; Collins, C. L.; Cooper, B.; Deen, R. G.; Gupta, S.

    2013-01-01

    MAHLI (Mars Hand Lens Imager) is a 2-megapixel focusable macro lens color camera on the turret on Curiosity's robotic arm. The investigation centers on stratigraphy, grain-scale texture, structure, mineralogy, and morphology of geologic materials at Curiosity's Gale robotic field site. MAHLI acquires focused images at working distances of 2.1 cm to infinity; for reference, at 2.1 cm the scale is 14 microns/pixel; at 6.9 cm it is 31 microns/pixel, like the Spirit and Opportunity Microscopic Imager (MI) cameras.

  16. Magnetic resonance imaging as a tool for extravehicular activity analysis

    NASA Technical Reports Server (NTRS)

    Dickenson, R.; Lorenz, C.; Peterson, S.; Strauss, A.; Main, J.

    1992-01-01

    The purpose of this research is to examine the value of magnetic resonance imaging (MRI) as a means of conducting kinematic studies of the hand for the purpose of EVA capability enhancement. After imaging the subject hand using a magnetic resonance scanner, the resulting 2D slices were reconstructed into a 3D model of the proximal phalanx of the left hand. Using the coordinates of several landmark positions, one is then able to decompose the motion of the rigid body. MRI offers highly accurate measurements due to its tomographic nature without the problems associated with other imaging modalities for in vivo studies.

  17. The Offerings of Fringe Figures and Migrants

    ERIC Educational Resources Information Center

    Engels-Schwarzpaul, A.-Chr.

    2015-01-01

    "The Western tradition", as passe-partout, includes fringe figures, émigrés and migrants. Rather than looking to resources at the core of the Western tradition to overcome its own blindnesses, I am more interested in its gaps and peripheries, where other thoughts and renegade knowledges take hold. It is in the contact zones with…

  18. Cylindrical optic figuring dwell time optimization

    NASA Astrophysics Data System (ADS)

    Waluschka, Eugene

    2000-11-01

    The Constellation-X, grazing incidence, x-ray telescope may be fabricated from replicated segments. A series of mandrels will serve as the 'masters' in the replication processes. Diamond turning (milling) followed by abrasive figuring followed by a super polishing are the steps currently envisioned in making just one (of many) mandrel. The abrasive figuring of a mandrel is accomplished by moving a grinding tool along a helical path on this almost cylindrical surface. The measurement of the surface is, however, performed along 'axial' scan lines which intercept this helical path. This approach to figuring and measuring permits a relatively simple scheme to be implemented for the determination of the optimal dwell times of the figuring tool. These optimal dwell times are determined by a deconvolution which approaches the problem in a linear programming context and uses the Simplex Method. The approach maximizes the amount of material removed at any point subject to inequality constraints. The effects of using these 'optimum' dwell times is to significantly improve the tools effectiveness at removing the higher spatial frequencies while staying (strictly) within the bounds and constraints imposed by the hardware. In addition, the ringing at the edges of the optic, frequently present in deconvolution problems, is completely eliminated.

  19. Go Figure. HEADJAM. Teaching Guide [and Videotape].

    ERIC Educational Resources Information Center

    MATHCOUNTS Foundation, Alexandria, VA.

    The HeadJam series is comprised of six programs exploring mathematics, science, and critical thinking skills. It is an award-winning, educational videotape series for middle school students that explores multi-disciplinary skills in a highly entertaining way. The teacher's guide and 22-minute video, "Go Figure," demonstrate how math is used in the…

  20. Noise figure of hybrid optical parametric amplifiers.

    PubMed

    Marhic, Michel E

    2012-12-17

    Following a fiber optical parametric amplifier, used as a wavelength converter or in the phase-sensitive mode, by a phase-insensitive amplifier (PIA) can significantly reduce four-wave mixing between signals in broadband systems. We derive the quantum mechanical noise figures (NF) for these two hybrid configurations, and show that adding the PIA only leads to a moderate increase in NF.

  1. Computerized Testing: The Hidden Figures Test.

    ERIC Educational Resources Information Center

    Jacobs, Ronald L.; And Others

    1985-01-01

    This study adapted the Hidden Figures Test for use on PLATO and determined the reliability of the computerized version compared to the paper and pencil version. Results indicate the test was successfully adapted with some modifications, and it was judged reliable although it may be measuring additional constructs. (MBR)

  2. Human Figure Drawings of Vietnamese Children.

    ERIC Educational Resources Information Center

    Delatte, Joseph G. Jr.

    1978-01-01

    Some characteristics of the human figure drawings of 93 Vietnamese children were investigated. Drawings were scored according to the Goodenough method. Mental age scores were high in relation to chronological age and this result is explained in terms of cultural emphasis on the value of copying well. (SE)

  3. Facts and Figures about Chinese Americans.

    ERIC Educational Resources Information Center

    Association of Chinese Teachers, San Francisco, CA.

    In this brief collection of facts and figures about Chinese Americans, information and data are presented on the geographic location of Chinese in America, the pattern of Chinese immigration to the United States, and income and occupations of Chinese Americans. In addition, a brief chronology of Chinese American history is presented. (Author/AM)

  4. Cultural Impact on Human Figure Drawings.

    ERIC Educational Resources Information Center

    De La Serna, Marcelo; And Others

    1979-01-01

    A human figure drawing instrument was administered to Black children from the Virgin Islands and Georgia and to White children from Mexico. Both cultural and sex differences occurred, influencing the drawings. Black children from different cultures differed from each other on this instrument. (Author/BEF)

  5. 36 CFR Appendix - Figures to Part 1194

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 3 2011-07-01 2011-07-01 false Figures to Part 1194 Parks, Forests, and Public Property ARCHITECTURAL AND TRANSPORTATION BARRIERS COMPLIANCE BOARD ELECTRONIC AND INFORMATION TECHNOLOGY ACCESSIBILITY STANDARDS Information, Documentation, and Support Information, documentation, and support. Pt. 1194,...

  6. 36 CFR Appendix - Figures to Part 1192

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 3 2011-07-01 2011-07-01 false Figures to Part 1192 Parks, Forests, and Public Property ARCHITECTURAL AND TRANSPORTATION BARRIERS COMPLIANCE BOARD AMERICANS WITH DISABILITIES ACT (ADA) ACCESSIBILITY GUIDELINES FOR TRANSPORTATION VEHICLES Other Vehicles and Systems Trams, similar vehicles and systems. Pt....

  7. 36 CFR Appendix - Figures to Part 1192

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Figures to Part 1192 Parks, Forests, and Public Property ARCHITECTURAL AND TRANSPORTATION BARRIERS COMPLIANCE BOARD AMERICANS WITH DISABILITIES ACT (ADA) ACCESSIBILITY GUIDELINES FOR TRANSPORTATION VEHICLES Other Vehicles and Systems Trams, similar vehicles and systems. Pt....

  8. 36 CFR Appendix - Figures to Part 1194

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Figures to Part 1194 Parks, Forests, and Public Property ARCHITECTURAL AND TRANSPORTATION BARRIERS COMPLIANCE BOARD ELECTRONIC AND INFORMATION TECHNOLOGY ACCESSIBILITY STANDARDS Information, Documentation, and Support Information, documentation, and support. Pt. 1194,...

  9. T'ang Dynasty Tomb Figure.

    ERIC Educational Resources Information Center

    Selle, Penny

    1988-01-01

    Uses a print of a T'ang Dynasty tomb figure to acquaint grades 10-12 students with the tools needed for developing aesthetic judgement and artistic criticism. Includes background on the artwork and instructional strategies to help students describe the object, analyze the artmaking process, and formulate their own opinions. (GEA)

  10. Fading-Figure Tracing in Williams Syndrome

    ERIC Educational Resources Information Center

    Nagai, Chiyoko; Inui, Toshio; Iwata, Makoto

    2011-01-01

    Williams syndrome (WS) is a neurodevelopmental disorder characterized by severe impairment of visuospatial abilities. Figure-drawing abilities, which are thought to reflect visuospatial abilities, have yet to be fully investigated in WS. The purpose of the present study was to clarify whether drawing abilities differ between WS individuals and…

  11. Participation in the Figured World of Graffiti

    ERIC Educational Resources Information Center

    Valle, Imuris; Weiss, Eduardo

    2010-01-01

    This article is based on ethnographic work with two "crews" of young graffiti artists in southern Mexico City. The crews share certain characteristics with gangs or urban tribes, but more with "communities of practice": they live in the "figured world" of graffiti, a community of practice at the local and global…

  12. Self-assembled breath figure arrays of conjugated conducting polymers for photovoltaic application

    NASA Astrophysics Data System (ADS)

    Routh, Prahlad Kumar; Venkatesh, T. A.; Cotlet, Mircea

    2014-03-01

    Ordered microporous polymer structures have potential application in catalysis, surface engineering and optoelectronics. The Breath Figure Technique (BFT) is a simple method of producing such ordered microporous structures. In this study BFT was applied to a series of commercial conjugated polymer polythiophene derivatives with varying side chain length (n =6,8,10,12). An in-depth study of processing parameters has been carried with the aim of controlling the morphology of the honeycomb film over large, PV relevant areas. Structural and spectroscopic characterization of honeycomb films were performed using Scanning Electron Microscopy (SEM), X-ray scattering, Fluorescence Lifetime Imaging (FLIM) and Spectroscopy. Blends of these polymers with a fullerene derivative, PCBM, were also subjected to BFT and characterized with similar methods to assess their potential use as active layers in PV solar cells. Center for Functional Nanomaterials, Brookhaven National Laboratory.

  13. Effects of gender constancy and figure's height and sex on young children's gender-typed attributions.

    PubMed

    Levy, G D

    1998-01-01

    Young children's attributions of gender-typed activities to figures/models differing in height and/or sex were examined over three experiments. The influence of gender constancy understanding on children's gender-typed attributions was also examined. In Experiment 1, young children attributed significantly more masculine activities to male than female figures and significantly more feminine activities to female than male figures. Experiment 2 confirmed the results demonstrated in Experiment 1. In Experiment 2, additional line-drawn stimuli and figure comparisons were incorporated; participants attributed significantly more masculine activities to taller than shorter male figures and taller than shorter female figures. In addition, children attributed significantly more feminine activities to taller than shorter female figures. In Experiment 3, participants viewed pictures of taller and shorter male and female models. Results confirmed those of Experiment 1, as well as most of those of Experiment 2. No consistent patterns of children's gender-typed attributions as a function of gender constancy understanding emerged in the three experiments. Results are discussed as they apply to unexplored tenets from Kohlberg's cognitive-developmental model, as well as those of gender schema models, of early gender role development.

  14. Oculomotor Exploration of Impossible Figures in Early Infancy.

    PubMed

    Shuwairi, Sarah M; Johnson, Scott P

    2013-01-01

    Previous studies with young infants revealed that young infants can distinguish between displays of possible or impossible figures, which may require detection of inconsistent depth relations among local line junctions that disrupt global object configurations. Here, we used an eye-tracking paradigm to record eye movements in young infants during an object discrimination task with matched pairs of possible and impossible figures. Our goal was to identify differential patterns of oculomotor activity as infants viewed pictures of possible and impossible objects. We predicted that infants would actively attend to specific pictorial depth cues that denote shape (e.g., T-junctions), and in the context of an impossible figure that they would fixate to a greater extent in anomalous regions of the display relative to other parts. By the age of 4 months, infants fixated reliably longer overall on displays of impossible vs. possible cubes, specifically within the critical region where the incompatible lines and irreconcilable depth relations were located, implying an early capacity for selective attention to critical line junction information and integration of local depth cues necessary to perceive object coherence.

  15. Mirror Figuring Techniques of Sir William Herschel

    NASA Astrophysics Data System (ADS)

    Albin, E. F.

    2004-05-01

    Between the years 1773 to 1818, Sir William Herschel constructed dozens of speculum telescope mirrors, with diameters ranging from 6 - 48 inches. Very little, if any, detailed information has ever been published on the specifics of his mirror figuring efforts. The reason for this certainly relates to his desire to closely guard mirror production trade secrets. Upon Herschel's death, all telescope-making documents were passed on to his only son, Sir John Herschel. These materials are now in the possession of the British RAS and primarily consist of: a) a four volume series entitled "Experiments on the Construction of Specula," b) a 129 page treaty called "On the Construction of Specula," and c) a 179 page manuscript entitled "Results of Experiments on the Construction of Mirrors." It is suggested that publication was further delayed and then eventually abandoned due to silver-coated glass mirrors coming into favor. A recent investigation by the author, of the unpublished manuscripts on the construction of specula, suggests that Herschel's mirror figuring techniques did not involve any guess work; in fact, his methods were highly refined -- never leaving to chance the evolution of a spherical surface into the required paraboloid. At the heart of Herschel's figuring techniques were a series of aperture diaphragms (similar to the Couder masks used by modern telescope makers) that were placed over the mirror, which allowed for the precise determination of its curvature at various predefined zones. With this information, Herschel was able to vary his figuring strokes with his polishing tool accordingly. In addition, all mirrors were subsequently "star tested," sometimes with aperture diaphragms in place, allowing for field examination of the mirror's "distinctness" or performance. Double stars and the planet Saturn were favorite targets used to analyze and then correct a mirror's figure.

  16. Spatial Frequency Components of Images Modulate Neuronal Activity in Monkey Amygdala.

    PubMed

    Montes-Lourido, Pilar; Bermudez, M A; Romero, M C; Vicente, A F; Gonzalez, F

    2016-04-01

    Processing the spatial frequency components of an image is a crucial feature for visual perception, especially in recognition of faces. Here, we study the correlation between spatial frequency components of images of faces and neuronal activity in monkey amygdala while performing a visual recognition task. The frequency components of the images were analyzed using a fast Fourier transform for 40 spatial frequency ranges. We recorded 65 neurons showing statistically significant responses to at least one of the images used as a stimulus. A total of 37 of these neurons (n = 37) showed significant responses to at least three images, and in eight of them (8/37, 22%), we found a statistically significant correlation between neuron response and the modulus amplitude of at least one frequency range present in the images. Our results indicate that high spatial frequency and low spatial frequency components of images influence the activity of amygdala neurons.

  17. Functional Imaging of Chemically Active Surfaces with Optical Reporter Microbeads

    PubMed Central

    Ahuja, Punkaj; Nair, Sumitha; Narayan, Sreenath; Gratzl, Miklós

    2015-01-01

    We have developed a novel approach to allow for continuous imaging of concentration fields that evolve at surfaces due to release, uptake, and mass transport of molecules, without significant interference of the concentration fields by the chemical imaging itself. The technique utilizes optical “reporter” microbeads immobilized in a thin layer of transparent and inert hydrogel on top of the surface. The hydrogel has minimal density and therefore diffusion in and across it is like in water. Imaging the immobilized microbeads over time provides quantitative concentration measurements at each location where an optical reporter resides. Using image analysis in post-processing these spatially discrete measurements can be transformed into contiguous maps of the dynamic concentration field across the entire surface. If the microbeads are small enough relative to the dimensions of the region of interest and sparsely applied then chemical imaging will not noticeably affect the evolution of concentration fields. In this work colorimetric optode microbeads a few micrometers in diameter were used to image surface concentration distributions on the millimeter scale. PMID:26332766

  18. Noninvasive Imaging of the High Frequency Brain Activity in Focal Epilepsy Patients

    PubMed Central

    Lu, Yunfeng; Worrell, Gregory A.; Zhang, Huishi Clara; Yang, Lin; Brinkmann, Benjamin; Nelson, Cindy

    2014-01-01

    High frequency (HF) activity represents a potential biomarker of the epileptogenic zone in epilepsy patients, the removal of which is considered to be crucial for seizure-free surgical outcome. We proposed a high frequency source imaging (HFSI) approach to noninvasively image the brain sources of scalp recorded high frequency EEG activity. Both computer simulation and clinical patient data analysis were performed to investigate the feasibility of using the HFSI approach to image the sources of HF activity from noninvasive scalp EEG recordings. The HF activity was identified from high-density scalp recordings after high-pass filtering the EEG data and the EEG segments with HF activity were concatenated together to form repetitive HF activity. Independent component analysis was utilized to extract the components corresponding to the HF activity. Noninvasive EEG source imaging using realistic geometric boundary element head modeling was then applied to image the sources of the pathological HF brain activity. Five medically intractable focal epilepsy patients were studied and the estimated sources were found to be concordant with the surgical resection or intracranial recordings of the patients. The present study demonstrates, for the first time, that source imaging from the scalp HF activity could help to localize the seizure onset zone (SOZ) and provide a novel noninvasive way of studying the epileptic brain in humans. This study also indicates the potential application of studying HF activity in the pre-surgical planning of medically intractable epilepsy patients. PMID:24845275

  19. Neural dynamics of feedforward and feedback processing in figure-ground segregation.

    PubMed

    Layton, Oliver W; Mingolla, Ennio; Yazdanbakhsh, Arash

    2014-01-01

    Determining whether a region belongs to the interior or exterior of a shape (figure-ground segregation) is a core competency of the primate brain, yet the underlying mechanisms are not well understood. Many models assume that figure-ground segregation occurs by assembling progressively more complex representations through feedforward connections, with feedback playing only a modulatory role. We present a dynamical model of figure-ground segregation in the primate ventral stream wherein feedback plays a crucial role in disambiguating a figure's interior and exterior. We introduce a processing strategy whereby jitter in RF center locations and variation in RF sizes is exploited to enhance and suppress neural activity inside and outside of figures, respectively. Feedforward projections emanate from units that model cells in V4 known to respond to the curvature of boundary contours (curved contour cells), and feedback projections from units predicted to exist in IT that strategically group neurons with different RF sizes and RF center locations (teardrop cells). Neurons (convex cells) that preferentially respond when centered on a figure dynamically balance feedforward (bottom-up) information and feedback from higher visual areas. The activation is enhanced when an interior portion of a figure is in the RF via feedback from units that detect closure in the boundary contours of a figure. Our model produces maximal activity along the medial axis of well-known figures with and without concavities, and inside algorithmically generated shapes. Our results suggest that the dynamic balancing of feedforward signals with the specific feedback mechanisms proposed by the model is crucial for figure-ground segregation.

  20. Active Learning in Context-Driven Stream Mining With an Application to Image Mining.

    PubMed

    Tekin, Cem; van der Schaar, Mihaela

    2015-11-01

    We propose an image stream mining method in which images arrive with contexts (metadata) and need to be processed in real time by the image mining system (IMS), which needs to make predictions and derive actionable intelligence from these streams. After extracting the features of the image by preprocessing, IMS determines online the classifier to use on the extracted features to make a prediction using the context of the image. A key challenge associated with stream mining is that the prediction accuracy of the classifiers is unknown, since the image source is unknown; thus, these accuracies need to be learned online. Another key challenge of stream mining is that learning can only be done by observing the true label, but this is costly to obtain. To address these challenges, we model the image stream mining problem as an active, online contextual experts problem, where the context of the image is used to guide the classifier selection decision. We develop an active learning algorithm and show that it achieves regret sublinear in the number of images that have been observed so far. To further illustrate and assess the performance of our proposed methods, we apply them to diagnose breast cancer from the images of cellular samples obtained from the fine needle aspirate of breast mass. Our findings show that very high diagnosis accuracy can be achieved by actively obtaining only a small fraction of true labels through surgical biopsies. Other applications include video surveillance and video traffic monitoring.

  1. Figure correction of multilayer coated optics

    DOEpatents

    Chapman; Henry N. , Taylor; John S.

    2010-02-16

    A process is provided for producing near-perfect optical surfaces, for EUV and soft-x-ray optics. The method involves polishing or otherwise figuring the multilayer coating that has been deposited on an optical substrate, in order to correct for errors in the figure of the substrate and coating. A method such as ion-beam milling is used to remove material from the multilayer coating by an amount that varies in a specified way across the substrate. The phase of the EUV light that is reflected from the multilayer will be affected by the amount of multilayer material removed, but this effect will be reduced by a factor of 1-n as compared with height variations of the substrate, where n is the average refractive index of the multilayer.

  2. Recommended Figures of Merit for Green Monopropellants

    NASA Technical Reports Server (NTRS)

    Marshall. William M.; Deans, Matthew C.

    2013-01-01

    Hydrazine propellant has historically been used as a rocket thruster monopropellant since the mid-1960s. Mission managers are well aware of its characteristics and performance. However, it is a known toxic chemical and a wide effort is underway to reduce and/or eliminate its use worldwide. Several new propellant combinations have been developed in the last few years which tout or promise to provide same or better performance as hydrazine while being "non-toxic" or "green". Yet, there is no consistent definition for what constitutes "non-toxic" or "green", and thus no good figure of merit for which to compare. This paper seeks to review the three major categories of figures of merit, and discusses how they might be used to assess the viability of a propellant.

  3. LETTER TO THE EDITOR: Significant figures

    NASA Astrophysics Data System (ADS)

    Wheeler, David

    2000-05-01

    The interesting article on `University students' conceptions of basic astronomy concepts' by Ricardo Trumper (2000 Phys. Educ. 35 9-15) was spoiled by a lack of attention to detail. The percentages for the student responses were mostly quoted to three figures but the sample size of 76 allows for only two at most. As well as making the article much less `readable', the decimal point in the percentage figure implies a measurement accuracy that is just not there in reality. Sociologists and newspaper reporters have long been guilty of this kind of accidental deception. If we physicists don't set an example in our own journals how can we ever expect it to stop?

  4. Figure and finish of grazing incidence mirrors

    SciTech Connect

    Takacs, P.Z. ); Church, E.L. . Army Armament Research, Development and Engineering Center)

    1989-08-01

    Great improvement has been made in the past several years in the quality of optical components used in synchrotron radiation (SR) beamlines. Most of this progress has been the result of vastly improved metrology techniques and instrumentation permitting rapid and accurate measurement of the surface finish and figure on grazing incidence optics. A significant theoretical effort has linked the actual performance of components used as x-ray wavelengths to their topological properties as measured by surface profiling instruments. Next-generation advanced light sources will require optical components and systems to have sub-arc second surface figure tolerances. This paper will explore the consequences of these requirements in terms of manufacturing tolerances to see if the present manufacturing state-of-the-art is capable of producing the required surfaces. 15 refs., 14 figs., 2 tabs.

  5. High figure of merit thermoelectrics - Theoretical considerations

    NASA Technical Reports Server (NTRS)

    Vining, Cronin B.

    1990-01-01

    The thermoelectric figure of merit of a semiconductor, ZT, can be calculated from a small number of microscopic material parameters, the material composition, the doping level, and the temperature. The functional dependence of ZT on these parameters has been studied for a range of material parameters using a recently developed model which accurately and self-consistently describes the thermoelectric properties of n-type silicon-germanium alloys. ZT values several times larger than current state-of-the-art values of ZT of about 1 are shown to be entirely consistent with existing theory, even using material parameters already observed. A search for materials with much higher figure of merit values therefore remains of interest, in spite of several decades of relatively slow progress in this area.

  6. Adolescent girls' parasocial interactions with media figures.

    PubMed

    Theran, Sally A; Newberg, Emily M; Gleason, Tracy R

    2010-01-01

    We examined aspects of adolescent girls' parasocial interactions in the context of typical development. Parasocial interactions are defined as symbolic, one-sided quasi-interactions between a viewer and a media figure. In total, 107 adolescent girls were examined; 94% reported engaging in parasocial interactions to some degree. Preoccupied attachment style predicted the degree of involvement in and emotional intensity of parasocial interactions. Results suggest that parasocial interactions are characteristic of girls with preoccupied attachment, but are also part of normative development.

  7. In harbor underwater threat detection/identification using active imaging

    NASA Astrophysics Data System (ADS)

    Weidemann, Alan; Fournier, Georges R.; Forand, Luc; Mathieu, Pierre

    2005-05-01

    We present results from trials of the LUCIE 2 (Laser Underwater Camera Image Enhancer) conducted in Halifax Harbor, Nova Scotia, Canada and Esquimalt Harbor, Victoria, British Columbia, Canada. LUCIE 2 is a new compact laser range gated camera (10 inches in diameter, 24 inches in length, and neutrally buoyant in water) originally designed to improve search and recovery operations under eye safe restrictions. The flexibility and eye safety of this second generation LUCIE makes it a tool for improved hull searches and force protection operations when divers are in the water attempting to identify bottom lying objects. The camera is equipped with a full image geo-positioning system. To cover various environmental and targets size conditions, the gate-delay, gate width, polarization and viewing and illuminating angles can be varied as well. We present an analysis on the performance of the system in various water conditions using several target types and a comparison with diver and camera identification. Coincident in-situ optical properties of absorption and scattering were taken to help resolve the environmental information contained in the LUCIE image. Several new capabilities are currently being designed and tested, among them a differential polarization imaging system, a stabilized line of sight system with step-stare capability for high resolution mosaic area coverage, a precision dimensioning system and a diver guided and operated version.

  8. Changes in area affect figure-ground assignment in pigeons.

    PubMed

    Castro, Leyre; Lazareva, Olga F; Vecera, Shaun P; Wasserman, Edward A

    2010-03-05

    A critical cue for figure-ground assignment in humans is area: smaller regions are more likely to be perceived as figures than are larger regions. To see if pigeons are similarly sensitive to this cue, we trained birds to report whether a target appeared on a colored figure or on a differently colored background. The initial training figure was either smaller than (Experiments 1 and 2) or the same area as (Experiment 2) the background. After training, we increased or decreased the size of the figure. When the original training shape was smaller than the background, pigeons' performance improved with smaller figures (and worsened with larger figures); when the original training shape was the same area as the background, pigeons' performance worsened when they were tested with smaller figures. A smaller figural region appeared to improve the figure-ground discrimination only when size was a relevant cue in the initial discrimination.

  9. Concealed objects detection based on FWT in active millimeter-wave images

    NASA Astrophysics Data System (ADS)

    Du, Kun; Zhang, Lu; Chen, Wei; Wan, Guolong; Fu, Ruoran

    2017-01-01

    Active millimeter-wave (MMW) near-filed human imaging is a means for concealed objects detection. A method of concealed objects detection based on fast wavelet transforms (FWT) in the usage of active MMW images is presented as a result of image characteristics, which includes high resolution, characteristics varying in different parts of the human, imaging influenced among human, concealed objects and other objects, and different textures of concealed objects. Images segmentation utilizing results of edge detection based on FWT is conducted and preliminary segmentation results can be obtained. Some kinds of concealed objects according to comparing gray value of concealed objects to human average gray value can be detected in this paper. The experiments of concealed objects on images of actual acquisition are conducted with a result of accurate rate 80.92% and false alarm rate 11.78%, illustrating the effectiveness of the method proposed in this paper.

  10. Differential Deposition for Surface Figure Corrections in Grazing Incidence X-Ray Optics

    NASA Technical Reports Server (NTRS)

    Ramsey, Brian D.; Kilaru, Kiranmayee; Atkins, Carolyn; Gubarev, Mikhail V.; Broadway, David M.

    2015-01-01

    Differential deposition corrects the low- and mid- spatial-frequency deviations in the axial figure of Wolter-type grazing incidence X-ray optics. Figure deviations is one of the major contributors to the achievable angular resolution. Minimizing figure errors can significantly improve the imaging quality of X-ray optics. Material of varying thickness is selectively deposited, using DC magnetron sputtering, along the length of optic to minimize figure deviations. Custom vacuum chambers are built that can incorporate full-shell and segmented Xray optics. Metrology data of preliminary corrections on a single meridian of full-shell x-ray optics show an improvement of mid-spatial frequencies from 6.7 to 1.8 arc secs HPD. Efforts are in progress to correct a full-shell and segmented optics and to verify angular-resolution improvement with X-ray testing.

  11. Soft-tissues Image Processing: Comparison of Traditional Segmentation Methods with 2D active Contour Methods

    NASA Astrophysics Data System (ADS)

    Mikulka, J.; Gescheidtova, E.; Bartusek, K.

    2012-01-01

    The paper deals with modern methods of image processing, especially image segmentation, classification and evaluation of parameters. It focuses primarily on processing medical images of soft tissues obtained by magnetic resonance tomography (MR). It is easy to describe edges of the sought objects using segmented images. The edges found can be useful for further processing of monitored object such as calculating the perimeter, surface and volume evaluation or even three-dimensional shape reconstruction. The proposed solutions can be used for the classification of healthy/unhealthy tissues in MR or other imaging. Application examples of the proposed segmentation methods are shown. Research in the area of image segmentation focuses on methods based on solving partial differential equations. This is a modern method for image processing, often called the active contour method. It is of great advantage in the segmentation of real images degraded by noise with fuzzy edges and transitions between objects. In the paper, results of the segmentation of medical images by the active contour method are compared with results of the segmentation by other existing methods. Experimental applications which demonstrate the very good properties of the active contour method are given.

  12. Figuring Out Food Labels (For Kids)

    MedlinePlus

    ... in your class to have one cookie each. Math comes in handy with food labels! Calories and ... The Nemours Foundation, iStock, Getty Images, Corbis, Veer, Science Photo Library, Science Source Images, Shutterstock, and Clipart. ...

  13. Teaching active transport at the turn of the twenty-first century: recent discoveries and conceptual changes.

    PubMed Central

    Inesi, G

    1994-01-01

    The conceptual advances introduced by recent discoveries in the field of active transport have triggered a transition from a "black box" approach to a "mechanistic" approach. At present, treating this subject in the graduate setting requires consideration of equilibrium and kinetic experimentation, protein chemistry, mutational analysis and molecular structure, with the aim of defining the "transport machine." Images FIGURE 4 FIGURE 5 FIGURE 6 PMID:8011889

  14. Cue-invariant networks for figure and background processing in human visual cortex.

    PubMed

    Appelbaum, L Gregory; Wade, Alex R; Vildavski, Vladimir Y; Pettet, Mark W; Norcia, Anthony M

    2006-11-08

    Lateral occipital cortical areas are involved in the perception of objects, but it is not clear how these areas interact with first tier visual areas. Using synthetic images portraying a simple texture-defined figure and an electrophysiological paradigm that allows us to monitor cortical responses to figure and background regions separately, we found distinct neuronal networks responsible for the processing of each region. The figure region of our displays was tagged with one temporal frequency (3.0 Hz) and the background region with another (3.6 Hz). Spectral analysis was used to separate the responses to the two regions during their simultaneous presentation. Distributed source reconstructions were made by using the minimum norm method, and cortical current density was measured in a set of visual areas defined on retinotopic and functional criteria with the use of functional magnetic resonance imaging. The results of the main experiments, combined with a set of control experiments, indicate that the figure region, but not the background, was routed preferentially to lateral cortex. A separate network extending from first tier through more dorsal areas responded preferentially to the background region. The figure-related responses were mostly invariant with respect to the texture types used to define the figure, did not depend on its spatial location or size, and mostly were unaffected by attentional instructions. Because of the emergent nature of a segmented figure in our displays, feedback from higher cortical areas is a likely candidate for the selection mechanism by which the figure region is routed to lateral occipital cortex.

  15. Comparison of passive ranging integral imaging and active imaging digital holography for three-dimensional object recognition.

    PubMed

    Frauel, Yann; Tajahuerce, Enrique; Matoba, Osamu; Castro, Albertina; Javidi, Bahram

    2004-01-10

    We present an overview of three-dimensional (3D) object recognition techniques that use active sensing by interferometric imaging (digital holography) and passive sensing by integral imaging. We describe how each technique can be used to retrieve the depth information of a 3D scene and how this information can then be used for 3D object recognition. We explore various algorithms for 3D recognition such as nonlinear correlation and target distortion tolerance. We also provide a comparison of the advantages and disadvantages of the two techniques.

  16. Some Problems for Representations of Brain Organization Based on Activation in Functional Imaging

    ERIC Educational Resources Information Center

    Sidtis, John J.

    2007-01-01

    Functional brain imaging has overshadowed traditional lesion studies in becoming the dominant approach to the study of brain-behavior relationships. The proponents of functional imaging studies frequently argue that this approach provides an advantage over lesion studies by observing normal brain activity in vivo without the disruptive effects of…

  17. Figures of merit for CMOS SPADs and arrays

    NASA Astrophysics Data System (ADS)

    Bronzi, D.; Villa, F.; Bellisai, S.; Tisa, S.; Ripamonti, G.; Tosi, A.

    2013-05-01

    SPADs (Single Photon Avalanche Diodes) are emerging as most suitable photodetectors for both single-photon counting (Fluorescence Correlation Spectroscopy, Lock-in 3D Ranging) and single-photon timing (Lidar, Fluorescence Lifetime Imaging, Diffuse Optical Imaging) applications. Different complementary metal-oxide semiconductor (CMOS) implementations have been reported in literature. We present some figure of merit able to summarize the typical SPAD performances (i.e. Dark Counting Rate, Photo Detection Efficiency, afterpulsing probability, hold-off time, timing jitter) and to identify a proper metric for SPAD comparison, both as single detectors and also as imaging arrays. The goal is to define a practical framework within which it is possible to rank detectors based on their performances in specific experimental conditions, for either photon-counting or photon-timing applications. Furthermore we review the performances of some CMOS and custom-made SPADs. Results show that CMOS SPADs performances improve as the technology scales down; moreover, miniaturization of SPADs and new solutions adopted to counteract issues related with the SPAD design (electric field uniformity, premature edge breakdown, tunneling effects, defect-rich STI interface) along with advances in standard CMOS processes led to a general improvement in all fabricated photodetectors; therefore, CMOS SPADs can be suitable for very dense and cost-effective many-pixels imagers with high performances.

  18. Active multispectral imaging system for photodiagnosis and personalized phototherapies

    NASA Astrophysics Data System (ADS)

    Ugarte, M. F.; Chávarri, L.; Briz, S.; Padrón, V. M.; García-Cuesta, E.

    2014-10-01

    The proposed system has been designed to identify dermatopathologies or to apply personalized phototherapy treatments. The system emits electromagnetic waves in different spectral bands in the range of visible and near infrared to irradiate the target (skin or any other object) to be spectrally characterized. Then, an imaging sensor measures the target response to the stimulus at each spectral band and, after processing, the system displays in real time two images. In one of them the value of each pixel corresponds to the more reflected wavenumber whereas in the other image the pixel value represents the energy absorbed at each band. The diagnosis capability of this system lies in its multispectral design, and the phototherapy treatments are adapted to the patient and his lesion by measuring his absorption capability. This "in situ" absorption measurement allows us to determine the more appropriate duration of the treatment according to the wavelength and recommended dose. The main advantages of this system are its low cost, it does not have moving parts or complex mechanisms, it works in real time, and it is easy to handle. For these reasons its widespread use in dermatologist consultation would facilitate the work of the dermatologist and would improve the efficiency of diagnosis and treatment. In fact the prototype has already been successfully applied to pathologies such as carcinomas, melanomas, keratosis, and nevi.

  19. Active multispectral imaging system for photodiagnosis and personalized phototherapies

    SciTech Connect

    Ugarte, M. F. E-mail: sbriz@fis.uc3m.es; Chávarri, L.; Padrón, V. M.; García-Cuesta, E.

    2014-10-15

    The proposed system has been designed to identify dermatopathologies or to apply personalized phototherapy treatments. The system emits electromagnetic waves in different spectral bands in the range of visible and near infrared to irradiate the target (skin or any other object) to be spectrally characterized. Then, an imaging sensor measures the target response to the stimulus at each spectral band and, after processing, the system displays in real time two images. In one of them the value of each pixel corresponds to the more reflected wavenumber whereas in the other image the pixel value represents the energy absorbed at each band. The diagnosis capability of this system lies in its multispectral design, and the phototherapy treatments are adapted to the patient and his lesion by measuring his absorption capability. This “in situ” absorption measurement allows us to determine the more appropriate duration of the treatment according to the wavelength and recommended dose. The main advantages of this system are its low cost, it does not have moving parts or complex mechanisms, it works in real time, and it is easy to handle. For these reasons its widespread use in dermatologist consultation would facilitate the work of the dermatologist and would improve the efficiency of diagnosis and treatment. In fact the prototype has already been successfully applied to pathologies such as carcinomas, melanomas, keratosis, and nevi.

  20. Present and Future Activities on Neutron Imaging in Argentina

    NASA Astrophysics Data System (ADS)

    Tartaglione, Aureliano; Blostein, Jerónimo; Cantargi, Florencia; Marín, Julio; Baruj, Alberto; Meyer, Gabriel; Santisteban, Javier; Sánchez, Fernando

    We present here a short review of the main work which has been done in the latest years in neutron imaging in Argentina, and the future plans for the development of this technique in the country, mainly focused in the design of a new neutron imaging instrument to be installed in the future research reactor RA10. We present here the results of the implementation of the technique in samples belonging to the Argentinean cultural heritage and experiments related with hydrogen storage. At the same time, the Argentinean RA10 project for the design and construction of a 30 MW multipurpose research reactor is rapidly progressing. It started to be designed by the National Atomic Energy Commission (CNEA) and the technology company INVAP SE, both from Argentina, in June 2010. The construction will start in the beginning of 2015 in the Ezeiza Atomic Center, at 36 km from Buenos Aires City, and is expected to be finished by 2020. One of the main aims of the project is to offer to the Argentinean scientific and technology system new capabilities based on neutron techniques. We present here the conceptual design of a neutron imaging facility which will use one of the cold neutron beams, and will be installed in the reactor hall. Preliminary simulation results show that at the farthest detection position, at about 17 m from the cold source, a uniform neutron beam on a detection screen with an intensity of about 108 n/cm2/s is expected.

  1. Characteristics of Monolithically Integrated InGaAs Active Pixel Image Array

    NASA Technical Reports Server (NTRS)

    Kim, Q.; Cunningham, T. J.; Pain, B.; Lange, M. J.; Olsen, G. H.

    1999-01-01

    Switching and amplifying characteristics of a newly developed monolithic InGaAs Active Pixel Imager Array are presented. The sensor array is fabricated from InGaAs material epitaxially deposited on an InP substrate.

  2. Novel assay for direct fluorescent imaging of sialidase activity

    NASA Astrophysics Data System (ADS)

    Tomin, A.; Shkandina, T.; Bilyy, R.

    2011-07-01

    Here we describe a novel approach to sialidase activity estimation. Sialidases (EC 3.2.1.18, exo-α-sialidases), also known as neuraminidases, are the group of enzymes, which hydrolyze the glycoside bound between terminal sialic acid and subsequent carbohydrate residue in glycoproteins and glycolipids. Sialic acids are the group of monosaccharides with acidic properties, since they are acetylated or glycolylated derivates of neuraminic acid. Flu and some other viruses use neuraminidase activity to infect host cells. The level of sialylation was shown to be tightly connected with tumor cell invasiveness and metastatic potential, sialylation level also determines the clearance of aged or virus-infected cells. Thus, detection of sialidase activity is of primary importance for clinical diagnostics as well as life science research. The authors developed the assay for both visualization and estimation of sialidase activity in living cells. Previously known methods for sialidase activity detection required destruction of cellular material, or were low-sensitive, or provided no information on the activity localization in certain intracellular compartment. To overcome these problems, a fluorogenic neuraminidase substrate, 4-MUNA was utilized, and the method for detection of neuraminidase activity using fluorescent microscopy was proposed, it provided a high signal level and information on cellular localization of the studied enzyme. By using this approach the increase of sialidase activity on apoptotic cells was demonstrated in comparison to viable and primary necrotic cells.

  3. Decoding figure-ground occlusions from contours and shading

    NASA Astrophysics Data System (ADS)

    Kim, Juno; Anstis, Stuart

    2016-07-01

    Visual experience of surface properties relies on accurately attributing encoded luminance variations (e.g., edges and contours) to any one of several potential environmental causes. We examined the role of differences in the local shading directions across sharp contours in (i) identifying occlusion boundaries and (ii) perceiving the depth layout of adjacent surfaces. We used graphical rendering to control the orientation of a simulated light source, and hence the shading direction between adjacent surface regions that met at a common edge. We call the difference in shading direction across the edge the delta shading angle. We found that delta-shaded edges looked like occluding boundaries. We also found that the perceived figure-ground organisation of the adjacent surface regions depended on an assumed lighting from above prior. Shaded regions experienced as convex surfaces illuminated from above were perceived as occluding surfaces in the foreground. We computed an image-based measure of delta shading using the difference in local shading direction (the orientation field) and found this model could reliably account for observer judgments of surface occlusion, better than local (in-)coherence in the orientation of isophotes across the edge alone. However, additional information from co-alignment of isophotes relative to the edge is necessary to explain figure-ground distinctions across a broad class of occlusion events. We conclude that both local and global measures of shading direction are needed to explain perceived scene organisation, and material appearance more generally.

  4. Thermoelectric figure of merit in topological insulators

    NASA Astrophysics Data System (ADS)

    Takahashi, Ryuji; Murakami, Shuichi

    2011-07-01

    Transport behavior of two-dimensional topological insulators is theoretically studied in narrow ribbon geometry. The system has perfectly conducting edge channels, which are free from backscattering. At high temperature, the bulk states dominate in the transport phenomenon. However, at low temperature the conducting channels along the edges become dominant. It causes a bulk-to-edge crossover. Namely, by lowering temperature, the figure of merit first decreases by a competition between the bulk and the edge transport, and then increases again because the edge transport become larger.

  5. Active Signal Propagation and Imaging Using Vortex Beams

    DTIC Science & Technology

    2014-08-01

    waist , and 2p+ l+1( )arctan(z / zR ) is the Gouy phase where zR is the Rayleigh range. The order of the Laguerre-Gaussian mode is given by N = 2p...cause them to rotate around the circumference of the optical vortex . 1.1. Guide-probe experiment Implementation of OV-GP imaging is based on...polarized Gaussian beam from a Helium-Neon laser cavity (633nm, ~5mW) is expanded and collimated to a beam waist of ~5mm and converted into an OV baring

  6. Real-time imaging of Rab5 activity using a prequenched biosensor.

    PubMed

    Zhan, Ke; Xie, Hexin; Gall, Jessica; Ma, Manlung; Griesbeck, Oliver; Salehi, Ahmad; Rao, Jianghong

    2011-07-15

    A key regulator of receptor-mediated endocytosis, Rab5, plays a pivotal role in cargo receptor internalization, endosomal maturation, and transduction and degradation of internalized signaling molecules and recycling cargo receptor. Stressful conditions within cells lead to increased Rab5 activation, and increasing evidence correlates Rab5 activity abnormalities with certain diseases. Current antibody-based imaging methods cannot distinguish active Rab5 from total Rab5 population and provide dynamic information on magnitude and duration of Rab5 activation in cellular events and pathogenesis. We report here novel molecular imaging probes that specifically target GTP-bound Rab5 associated with the early endosome membrane in live cells and fixed mouse brain tissues. Our Rab5 activity fluorescent biosensor (RAFB) contains the Rab5 binding domain of the Rab5 effector Rabaptin 5, a fluorophore (a quantum dot or fluorescent dye) and a cell-penetrating peptide for live-cell delivery. The quantum dot conjugated RAFB was able to image the elevated Rab5 activity in both the cortex and hippocampi tissues of a Ts65Dn mouse. A prequenched RAFB based on fluorescence resonance energy transfer (FRET) can image cytosolic active Rab5 in single live cells. This novel method should enable imaging of the biological process in which Rab5 activity is regulated in various cellular systems.

  7. Validation of a new image analysis procedure for quantifying filamentous bacteria in activated sludge.

    PubMed

    Liwarska-Bizukojc, Ewa; Bizukojc, Marcin; Andrzejczak, Olga

    2014-01-01

    Quantification of filamentous bacteria in activated sludge systems can be made by manual counting under a microscope or by the application of various automated image analysis procedures. The latter has been significantly developed in the last two decades. In this work a new method based upon automated image analysis techniques was elaborated and presented. It consisted of three stages: (a) Neisser staining, (b) grabbing of microscopic images, and (c) digital image processing and analysis. This automated image analysis procedure possessed the features of novelty. It simultaneously delivered data about aggregates and filaments in an individual calculation routine, which is seldom met in the procedures described in the literature so far. What is more important, the macroprogram performing image processing and calculation of morphological parameters was written in the same software which was used for grabbing of images. Previously published procedures required using two different types of software, one for image grabbing and another one for image processing and analysis. Application of this new procedure for the quantification of filamentous bacteria in the full-scale as well as laboratory activated sludge systems proved that it was simple, fast and delivered reliable results.

  8. A partition-based active contour model incorporating local information for image segmentation.

    PubMed

    Shi, Jiao; Wu, Jiaji; Paul, Anand; Jiao, Licheng; Gong, Maoguo

    2014-01-01

    Active contour models are always designed on the assumption that images are approximated by regions with piecewise-constant intensities. This assumption, however, cannot be satisfied when describing intensity inhomogeneous images which frequently occur in real world images and induced considerable difficulties in image segmentation. A milder assumption that the image is statistically homogeneous within different local regions may better suit real world images. By taking local image information into consideration, an enhanced active contour model is proposed to overcome difficulties caused by intensity inhomogeneity. In addition, according to curve evolution theory, only the region near contour boundaries is supposed to be evolved in each iteration. We try to detect the regions near contour boundaries adaptively for satisfying the requirement of curve evolution theory. In the proposed method, pixels within a selected region near contour boundaries have the opportunity to be updated in each iteration, which enables the contour to be evolved gradually. Experimental results on synthetic and real world images demonstrate the advantages of the proposed model when dealing with intensity inhomogeneity images.

  9. Efficient thermal image segmentation through integration of nonlinear enhancement with unsupervised active contour model

    NASA Astrophysics Data System (ADS)

    Albalooshi, Fatema A.; Krieger, Evan; Sidike, Paheding; Asari, Vijayan K.

    2015-03-01

    Thermal images are exploited in many areas of pattern recognition applications. Infrared thermal image segmentation can be used for object detection by extracting regions of abnormal temperatures. However, the lack of texture and color information, low signal-to-noise ratio, and blurring effect of thermal images make segmenting infrared heat patterns a challenging task. Furthermore, many segmentation methods that are used in visible imagery may not be suitable for segmenting thermal imagery mainly due to their dissimilar intensity distributions. Thus, a new method is proposed to improve the performance of image segmentation in thermal imagery. The proposed scheme efficiently utilizes nonlinear intensity enhancement technique and Unsupervised Active Contour Models (UACM). The nonlinear intensity enhancement improves visual quality by combining dynamic range compression and contrast enhancement, while the UACM incorporates active contour evolutional function and neural networks. The algorithm is tested on segmenting different objects in thermal images and it is observed that the nonlinear enhancement has significantly improved the segmentation performance.

  10. An enzymatically activated fluorescence probe for targeted tumor imaging

    PubMed Central

    Kamiya, Mako; Kobayashi, Hisataka; Hama, Yukihiro; Koyama, Yoshinori; Bernardo, Marcelino; Nagano, Tetsuo; Choyke, Peter L.; Urano, Yasuteru

    2008-01-01

    β-Galactosidase is a widely used reporter enzyme, but although several substrates are available for in vitro detection, its application for in vivo optical imaging remains a challenge. To obtain a probe suitable for in vivo use, we modified our previously developed activatable fluorescence probe, TG-βGal (J. Am. Chem. Soc., 2005, 127, 4888-4894), on the basis of photochemical and photophysical experiments. The new probe, AM-TG-βGal, provides a dramatic fluorescence enhancement upon reaction with β-galactosidase, and further hydrolysis of the ester moiety by ubiquitous intracellular esterases affords a hydrophilic product that is well retained within the cells without loss of fluorescence. We used a mouse tumor model to assess the practical utility of AM-TG-βGal, after confirming that tumors in the model could be labeled with avidin-β-galactosidase conjugate. This conjugate was administered to the mice in vivo, followed by AM-TG-βGal, and subsequent ex vivo fluorescence imaging clearly visualized intraperitoneal tumors as small as 200 μm. This strategy has potential clinical application, for example in video-assisted laparoscopic tumor resection. PMID:17352471

  11. Major depressive disorder is characterized by greater reward network activation to monetary than pleasant image rewards.

    PubMed

    Smoski, Moria J; Rittenberg, Alison; Dichter, Gabriel S

    2011-12-30

    Anhedonia, the loss of interest or pleasure in normally rewarding activities, is a hallmark feature of unipolar Major Depressive Disorder (MDD). A growing body of literature has identified frontostriatal dysfunction during reward anticipation and outcomes in MDD. However, no study to date has directly compared responses to different types of rewards such as pleasant images and monetary rewards in MDD. To investigate the neural responses to monetary and pleasant image rewards in MDD, a modified Monetary Incentive Delay task was used during functional magnetic resonance imaging to assess neural responses during anticipation and receipt of monetary and pleasant image rewards. Participants included nine adults with MDD and 13 affectively healthy controls. The MDD group showed lower activation than controls when anticipating monetary rewards in right orbitofrontal cortex and subcallosal cortex, and when anticipating pleasant image rewards in paracingulate and supplementary motor cortex. The MDD group had relatively greater activation in right putamen when anticipating monetary versus pleasant image rewards, relative to the control group. Results suggest reduced reward network activation in MDD when anticipating rewards, as well as relatively greater hypoactivation to pleasant image than monetary rewards.

  12. Active contour segmentation using level set function with enhanced image from prior intensity.

    PubMed

    Kim, Sunhee; Kim, Youngjun; Lee, Deukhee; Park, Sehyung

    2015-01-01

    This paper presents a new active contour segmentation model using a level set function that can correctly capture both the strong and the weak boundaries of a target enclosed by bright and dark regions at the same time. We introduce an enhanced image obtained from prior information about the intensity of the target. The enhanced image emphasizes the regions where pixels have intensities close to the prior intensity. This enables a desirable segmentation of an image having a partially low contrast with the target surrounded by regions that are brighter or darker than the target. We define an edge indicator function on an original image, and local and regularization forces on an enhanced image. An edge indicator function and two forces are incorporated in order to identify the strong and weak boundaries, respectively. We established an evolution equation of contours in the level set formulation and experimented with several medical images to show the performance of the proposed method.

  13. Lipid lowering and imaging protease activation in atherosclerosis Lipid therapy and MMP imaging in atherosclerosis

    PubMed Central

    Challa, Azariyas; Zhang, Jiasheng; Golestani, Reza; Jung, Jae-Joon; Robinson, Simon; Sadeghi, Mehran M.

    2014-01-01

    Background Lipid lowering is a mainstay of modern therapeutic approach to atherosclerosis. We sought to evaluate matrix metalloproteinase (MMP)-targeted microSPECT imaging for tracking of the effect of lipid-lowering interventions on plaque biology in atherosclerotic mice in vivo. Methods and Results ApoE−/− mice fed on a high fat diet (HFD) for 2 months were randomly assigned to continuation of HFD, HFD plus simvastatin, HFD plus fenofibrate and high fat withdrawal (HFW). The animals underwent serial microSPECT/CT imaging using RP805, a 99mTc-labeled MMP-targeted tracer at 1 and 4 weeks after randomization. All three interventions reduced total blood cholesterol by 4 weeks. In animals on HFD, aortic arch RP805 uptake significantly increased from 1 week to 4 weeks. Tracer uptake in fenofibrate and HFW groups was significantly lower than uptake in the HFD group at 4 weeks. Similarly, CD 68 gene expression, reflecting plaque inflammation, was significantly lower in fenofibrate and HFW groups compared to HFD group. MMP tracer uptake significantly correlated with aortic CD68, but not VE-cadherin or smooth muscle α-actin expression. Conclusions MMP tracer uptake paralleled the effect of lipid-lowering interventions on plaque inflammation in atherosclerotic mice. MMP-targeted imaging may be used to track the effect of therapeutic interventions in atherosclerosis. PMID:24368425

  14. Figures of Merit for Lunar Simulants

    NASA Astrophysics Data System (ADS)

    Slane, Frederick

    The collection and analysis of lunar samples from 1969 to present has yielded large amounts of data. Published analyses give some idea of the complex nature of the regolith at all scales, rocks, soils and the smaller particulates commonly referred to as dust. Data recently acquired in support of NASA's simulant effort has markedly increased our knowledge and quantitatively demonstrates that complexity. It is anticipated that future analyses will further add to the known complexity. In an effort to communicate among the diverse technical communities performing research on or research using regolith samples and simulants, a set of Figures of Merit (FoM) have been devised. The objective is to allow consistent and concise comparative communication between researchers from multiple organizations and nations engaged in lunar exploration. This paper describes Figures of Merit in a working draft of an international standard for Lunar Simulants. The FoM methodology uses scientific understanding of the lunar samples to formulate parameters which are reproducibly quantifiable. Advanced work at NASA has evolved this effort to the point that formal definitions, supporting mathematics and functioning code have implemented the concept for testing.

  15. Figure-ground separation by cue integration.

    PubMed

    Tang, Xiangyu; von der Malsburg, Christoph

    2008-06-01

    This letter presents an improved cue integration approach to reliably separate coherent moving objects from their background scene in video sequences. The proposed method uses a probabilistic framework to unify bottom-up and top-down cues in a parallel, "democratic" fashion. The algorithm makes use of a modified Bayes rule where each pixel's posterior probabilities of figure or ground layer assignment are derived from likelihood models of three bottom-up cues and a prior model provided by a top-down cue. Each cue is treated as independent evidence for figure-ground separation. They compete with and complement each other dynamically by adjusting relative weights from frame to frame according to cue quality measured against the overall integration. At the same time, the likelihood or prior models of individual cues adapt toward the integrated result. These mechanisms enable the system to organize under the influence of visual scene structure without manual intervention. A novel contribution here is the incorporation of a top-down cue. It improves the system's robustness and accuracy and helps handle difficult and ambiguous situations, such as abrupt lighting changes or occlusion among multiple objects. Results on various video sequences are demonstrated and discussed. (Video demos are available at http://organic.usc.edu:8376/ approximately tangx/neco/index.html .).

  16. Imaging of optically active biological structures by use of circularly polarized light.

    PubMed Central

    Keller, D; Bustamante, C; Maestre, M F; Tinoco, I

    1985-01-01

    If an optically active (chiral) sample is placed in a microscope and illuminated with circularly polarized light, an image can be formed that is related to the circular dichroism of each feature of the sample. A theoretical investigation has been done for the circular differential image obtained by subtracting the images formed under right- and left-circularly polarized light. Two types of differential images are possible: (i) dark-field images formed from light reflected or scattered by the sample and (ii) bright-field images formed from light transmitted through the sample. The sign and magnitude of each feature in a circular differential image strongly depend on the structure of the sample. The dark-field circular differential images are most sensitive to large features with dimensions similar to the wavelength of illumination whereas the bright-field images are most sensitive to the short-range molecular order. Applications of circular differential imaging may include clinical fingerprinting of normal and transformed cells and structural analysis of individual cellular components. PMID:3855558

  17. An addressable confocal microscope for functional imaging of neuronal activity

    NASA Astrophysics Data System (ADS)

    Bansal, Vivek

    2005-07-01

    The study of computation occurring in single neurons and small networks of interconnected neurons is often limited by (1) the number of sites that can be simultaneously probed with electrophysiology tools such as patch pipettes and (2) the recording speed of fluorescence imaging tools such as confocal or multiphoton microscopy. Even in the line scan mode of galvanometer-based scanners, where one scan dimension is sacrificed to gain overall speed, the effective frame rate is limited to less than 1 kHz with no flexibility in site selection. To overcome these limitations and allow the study of many sites throughout the dendritic arbor, we have developed an addressable confocal laser-scanning microscope that permits recording from user-selected sites-of-interest at high frame rates, in addition to conventional full frame imaging. Our system utilizes acousto-optic deflectors (AODs) in the illumination pathway to allow for rapid user-defined positioning of a focused laser spot. However, since AODs rely on diffraction to steer a laser beam, they cannot effectively descan the fluorescence emission spectrum as done in mirror-based systems which utilize reflection; this prevents the use of a stationary pinhole as a spatial filter. Instead, we implement an addressable spatial filter using a digital micromirror device (DMD) in conjunction with the AODs to achieve confocality. A registration algorithm synchronizes the AODs and DMD such that point illumination and point detection are always colocalized in conjugate image planes. The current version of the confocal system has a spatial resolution of ˜1 mum. Furthermore, by letting the user tailor which sites are visited, we have shown that recordings can be made at an aggregate frame rate of ˜40 kHz. We have successfully demonstrated that the system is capable of optical sectioning and thus exhibits the main advantage of a confocal microscope for light-scattering biological tissue. This property was used to create three

  18. [Specifics of perception of acoustic image of intrinsic bioelectric brain activity].

    PubMed

    Konstantinov, K V; Leonova, M K; Miroshnikov, D B; Klimenko, V M

    2014-06-01

    We studied the particularities of perception of the acoustic image of intrinsic EEG. We found that the assessment of perception of sounds, the presentation of which was synchronized and was agreed with current bioelectric brain activity, is higher that assessment of perception of acoustic EEG image presented in recorded form. Presentation of recorded acoustic image of EEG is accompanied by increased activity of beta-band in the frontal areas, while real-time presentation of acoustic EEG image is accompanied by the increase of slow wave activity: theta- and delta-bands of occipital areas of the brain. Increase activity in theta- and delta-bands of occipital areas in sessions of hearing the acoustic image of EEG in real time depend on the baseline frequency structure of EEG and correlates with expression of alpha-, beta- and theta-bands of bioelectric brain activity in both frontal and occipital areas. We suppose that presentation of sounds synchronized and agreed with the current bioelectric activity, activated the regulatory brain structures.

  19. Multiple Active Contours Guided by Differential Evolution for Medical Image Segmentation

    PubMed Central

    Cruz-Aceves, I.; Avina-Cervantes, J. G.; Lopez-Hernandez, J. M.; Rostro-Gonzalez, H.; Garcia-Capulin, C. H.; Torres-Cisneros, M.; Guzman-Cabrera, R.

    2013-01-01

    This paper presents a new image segmentation method based on multiple active contours guided by differential evolution, called MACDE. The segmentation method uses differential evolution over a polar coordinate system to increase the exploration and exploitation capabilities regarding the classical active contour model. To evaluate the performance of the proposed method, a set of synthetic images with complex objects, Gaussian noise, and deep concavities is introduced. Subsequently, MACDE is applied on datasets of sequential computed tomography and magnetic resonance images which contain the human heart and the human left ventricle, respectively. Finally, to obtain a quantitative and qualitative evaluation of the medical image segmentations compared to regions outlined by experts, a set of distance and similarity metrics has been adopted. According to the experimental results, MACDE outperforms the classical active contour model and the interactive Tseng method in terms of efficiency and robustness for obtaining the optimal control points and attains a high accuracy segmentation. PMID:23983809

  20. Active millimeter-wave imaging using a raster scanner

    NASA Astrophysics Data System (ADS)

    Hülsmann, Axel; Liebelt, Andreas; Tessmann, Axel; Leuther, Arnulf; Schlechtweg, Michael; Ambacher, Oliver

    2009-05-01

    A millimeter-wave imaging system has been developed operating at a center frequency of 94 GHz. The system has a single stationary mounted transmit and receive lensed horn antenna and two moving mirrors in x and y. The beam is generated by a FMCW-radar module. The final beam aperture is an off-set parabolic mirror which focuses the beam to a small spot at 2 m distance. Key component of the FMCW radar module is a MMIC, which includes a VCO, a MPA/HPA, two Lange-couplers, an LNA , a Wilkenson splitter, and an I/Q-mixer. This MMIC is fabricated using IAF's 100 nm metamorphic HEMT process.

  1. Interactive medical image segmentation using PDE control of active contours.

    PubMed

    Karasev, Peter; Kolesov, Ivan; Fritscher, Karl; Vela, Patricio; Mitchell, Phillip; Tannenbaum, Allen

    2013-11-01

    Segmentation of injured or unusual anatomic structures in medical imagery is a problem that has continued to elude fully automated solutions. In this paper, the goal of easy-to-use and consistent interactive segmentation is transformed into a control synthesis problem. A nominal level set partial differential equation (PDE) is assumed to be given; this open-loop system achieves correct segmentation under ideal conditions, but does not agree with a human expert's ideal boundary for real image data. Perturbing the state and dynamics of a level set PDE via the accumulated user input and an observer-like system leads to desirable closed-loop behavior. The input structure is designed such that a user can stabilize the boundary in some desired state without needing to understand any mathematical parameters. Effectiveness of the technique is illustrated with applications to the challenging segmentations of a patellar tendon in magnetic resonance and a shattered femur in computed tomography.

  2. Interactive Medical Image Segmentation using PDE Control of Active Contours

    PubMed Central

    Karasev, Peter; Kolesov, Ivan; Fritscher, Karl; Vela, Patricio; Mitchell, Phillip; Tannenbaum, Allen

    2014-01-01

    Segmentation of injured or unusual anatomic structures in medical imagery is a problem that has continued to elude fully automated solutions. In this paper, the goal of easy-to-use and consistent interactive segmentation is transformed into a control synthesis problem. A nominal level set PDE is assumed to be given; this open-loop system achieves correct segmentation under ideal conditions, but does not agree with a human expert's ideal boundary for real image data. Perturbing the state and dynamics of a level set PDE via the accumulated user input and an observer-like system leads to desirable closed-loop behavior. The input structure is designed such that a user can stabilize the boundary in some desired state without needing to understand any mathematical parameters. Effectiveness of the technique is illustrated with applications to the challenging segmentations of a patellar tendon in MR and a shattered femur in CT. PMID:23893712

  3. The structure function as a metric for roughness and figure

    NASA Astrophysics Data System (ADS)

    Parks, Robert E.; Tuell, Michael T.

    2016-09-01

    As optical designs become more sophisticated and incorporate aspheric and free form surfaces, the need to specify limits on mid-spatial frequency manufacturing errors becomes more critical, particularly as we better understand the effects of these errors on image quality. While there already exist methods based on Fourier analysis to specify these errors in most commercial interferometry software, the method of calculation and the power spectral density (PSD) results remain obscure to many in the optical design and manufacturing field. We suggest that the structure functions (SF) contains the same information as in the Fourier based PSD but in a way that is much more transparent to analysis, interpretation and application as a specification. The units of measure are more familiar and the concept behind the analysis is simpler to understand. Further, the information contained in the structure function (or PSD) allows a complete specification of an optical surface from the finest measurable detail of roughness to the overall figure. We discuss the origin of the structure function in the field of astronomy to describe the effects of air turbulence on image quality, the simple mathematical definition of the structure function and its easy means of calculation and how its results should be scaled depending on the location of the optical surface in a system from pupil to image plane. Finally, we give an example of how to write a specification of an optical surface using the structure function.

  4. Figure-ground organization in real and subjective contours: a new ambiguous figure, some novel measures of ambiguity, and apparent distance across regions of figure and ground.

    PubMed

    Shank, M D; Walker, J T

    1989-08-01

    This study was designed to assess the effects of organization, luminance contrast, sector angle, and orientation on a new, highly ambiguous Cs-keyhole figure. Organization and contrast were the most important factors, and sector angle also influenced figure-ground relationships. There was no significant effect of orientation, nor was there any significant interaction between any of the factors. Several new measures of figure-ground organization were developed, such as ambiguity ratios based on reaction times and on ratings of the strength of perceived organizations, providing new quantitative measures of figure-ground relationships. Distances measured across figural regions appeared smaller than equal distances across the ground in the new reversible figure, and also in Rubin's classic vase-face figure presented in real and subjective contours. Inducing a perceptual set to see a particular organization in a reversible figure influenced the apparent distance across that organization. Several possible explanations of the observed effects are considered: (1) an instance of Emmert's law, based on the difference in apparent depth of figure and ground; (2) an aspect of the Müller-Lyer illusion; (3) a feature-detector model of contour attraction; (4) a natural set or predisposition to see a figure as smaller; and (5) framing effects. The first two explanations appear the most promising.

  5. Reconstructing liver shape and position from MR image slices using an active shape model

    NASA Astrophysics Data System (ADS)

    Fenchel, Matthias; Thesen, Stefan; Schilling, Andreas

    2008-03-01

    We present an algorithm for fully automatic reconstruction of 3D position, orientation and shape of the human liver from a sparsely covering set of n 2D MR slice images. Reconstructing the shape of an organ from slice images can be used for scan planning, for surgical planning or other purposes where 3D anatomical knowledge has to be inferred from sparse slices. The algorithm is based on adapting an active shape model of the liver surface to a given set of slice images. The active shape model is created from a training set of liver segmentations from a group of volunteers. The training set is set up with semi-manual segmentations of T1-weighted volumetric MR images. Searching for the optimal shape model that best fits to the image data is done by maximizing a similarity measure based on local appearance at the surface. Two different algorithms for the active shape model search are proposed and compared: both algorithms seek to maximize the a-posteriori probability of the grey level appearance around the surface while constraining the surface to the space of valid shapes. The first algorithm works by using grey value profile statistics in normal direction. The second algorithm uses average and variance images to calculate the local surface appearance on the fly. Both algorithms are validated by fitting the active shape model to abdominal 2D slice images and comparing the shapes, which have been reconstructed, to the manual segmentations and to the results of active shape model searches from 3D image data. The results turn out to be promising and competitive to active shape model segmentations from 3D data.

  6. The interference effect of men's handling of muscular action figures on a lexical decision task.

    PubMed

    Barlett, Christopher P; Smith, Sara J; Harris, Richard J

    2006-12-01

    It has been shown in previous work [Action figures and men. Sex Roles 53, 877-885] that male participants who handled extremely muscular action figures had lower body esteem than those who did not handle action figures or a Ken doll. However, the internal mechanisms that dictated this effect are unclear. Therefore, the current study extended this previous work by having male participants handle action figures of varying muscularity and completing a lexical decision task with target words that consisted of both positive and negative body words and feeling words in order to determine if males would be primed to think negatively about their bodies and self or if positive thoughts about their bodies and self would be interfered with. The results show that those participants who handled the extremely muscular action figures responded significantly more slowly to feeling positive words (e.g., content, confident) and marginally more slowly to body positive words (e.g., muscle, bicep) than those who did not handle any action figures. Overall, this suggests that the interference of positive words, not the priming of negative words, is the internal mechanism that produces the decreased body image satisfaction after exposure to muscular stimuli. Implications and future research are discussed.

  7. Figure and ground in the visual cortex: v2 combines stereoscopic cues with gestalt rules.

    PubMed

    Qiu, Fangtu T; von der Heydt, Rüdiger

    2005-07-07

    Figure-ground organization is a process by which the visual system identifies some image regions as foreground and others as background, inferring 3D layout from 2D displays. A recent study reported that edge responses of neurons in area V2 are selective for side-of-figure, suggesting that figure-ground organization is encoded in the contour signals (border ownership coding). Here, we show that area V2 combines two strategies of computation, one that exploits binocular stereoscopic information for the definition of local depth order, and another that exploits the global configuration of contours (Gestalt factors). These are combined in single neurons so that the "near" side of the preferred 3D edge generally coincides with the preferred side-of-figure in 2D displays. Thus, area V2 represents the borders of 2D figures as edges of surfaces, as if the figures were objects in 3D space. Even in 3D displays, Gestalt factors influence the responses and can enhance or null the stereoscopic depth information.

  8. Profiling glycosyltransferase activities by tritium imaging of glycan microarrays.

    PubMed

    Serna, Sonia; Hokke, Cornelis H; Weissenborn, Martin; Flitsch, Sabine; Martin-Lomas, Manuel; Reichardt, Niels-Christian

    2013-05-10

    High-throughput microarray technology has been combined with ultrasensitive and high-resolution tritium autoradiography to create a new platform for the quantitative detection of glycosyltransferase activity on glycan arrays. In addition, we show full compatibility with the use of fluorescently labeled lectins to help with the stereochemical assignment of newly formed glycoside linkages.

  9. Images and Influences in the Promotion of Physical Activity

    ERIC Educational Resources Information Center

    Overdorf, Virginia

    2005-01-01

    This article presents the author's presentation on the 13th Delphine Hanna Commemorative Lecture in 2004. The presentation examines some of the problems and issues that must be addressed in order to promote physical activity in the academy and beyond. While there is no all embracing prescription, the author hopes to offer some suggestions that…

  10. Non-invasive imaging of neuroanatomical structures and neural activation with high-resolution MRI.

    PubMed

    Herberholz, Jens; Mishra, Subrata H; Uma, Divya; Germann, Markus W; Edwards, Donald H; Potter, Kimberlee

    2011-01-01

    Several years ago, manganese-enhanced magnetic resonance imaging (MEMRI) was introduced as a new powerful tool to image active brain areas and to identify neural connections in living, non-human animals. Primarily restricted to studies in rodents and later adapted for bird species, MEMRI has recently been discovered as a useful technique for neuroimaging of invertebrate animals. Using crayfish as a model system, we highlight the advantages of MEMRI over conventional techniques for imaging of small nervous systems. MEMRI can be applied to image invertebrate nervous systems at relatively high spatial resolution, and permits identification of stimulus-evoked neural activation non-invasively. Since the selection of specific imaging parameters is critical for successful in vivo micro-imaging, we present an overview of different experimental conditions that are best suited for invertebrates. We also compare the effects of hardware and software specifications on image quality, and provide detailed descriptions of the steps necessary to prepare animals for successful imaging sessions. Careful consideration of hardware, software, experiments, and specimen preparation will promote a better understanding of this novel technique and facilitate future MEMRI studies in other laboratories.

  11. Magnetic resonance image features identify glioblastoma phenotypic subtypes with distinct molecular pathway activities

    PubMed Central

    Itakura, Haruka; Achrol, Achal S.; Mitchell, Lex A.; Loya, Joshua J.; Liu, Tiffany; Westbroek, Erick M.; Feroze, Abdullah H.; Rodriguez, Scott; Echegaray, Sebastian; Azad, Tej D.; Yeom, Kristen W.; Napel, Sandy; Rubin, Daniel L.; Chang, Steven D.; Harsh, Griffith R.; Gevaert, Olivier

    2015-01-01

    Glioblastoma (GBM) is the most common and highly lethal primary malignant brain tumor in adults. There is a dire need for easily accessible, noninvasive biomarkers that can delineate underlying molecular activities and predict response to therapy. To this end, we sought to identify subtypes of GBM, differentiated solely by quantitative MR imaging features, that could be used for better management of GBM patients. Quantitative image features capturing the shape, texture, and edge sharpness of each lesion were extracted from MR images of 121 patients with de novo, solitary, unilateral GBM. Three distinct phenotypic “clusters” emerged in the development cohort using consensus clustering with 10,000 iterations on these image features. These three clusters—pre-multifocal, spherical, and rim-enhancing, names reflecting their image features—were validated in an independent cohort consisting of 144 multi-institution patients with similar tumor characteristics from The Cancer Genome Atlas (TCGA). Each cluster mapped to a unique set of molecular signaling pathways using pathway activity estimates derived from analysis of TCGA tumor copy number and gene expression data with the PARADIGM algorithm. Distinct pathways, such as c-Kit and FOXA, were enriched in each cluster, indicating differential molecular activities as determined by image features. Each cluster also demonstrated differential probabilities of survival, indicating prognostic importance. Our imaging method offers a noninvasive approach to stratify GBM patients and also provides unique sets of molecular signatures to inform targeted therapy and personalized treatment of GBM. PMID:26333934

  12. From static electric images to electric flow: towards dynamic perceptual cues in active electroreception.

    PubMed

    Hofmann, Volker; Sanguinetti-Scheck, Juan I; Gómez-Sena, Leonel; Engelmann, Jacob

    2013-01-01

    Active electroreception is an ancestral trait found in many aquatic vertebrates and has evolved independently in two teleost lineages, the Gymnotiformes and the Mormyriformes. Unique to these so-called weakly electric fish is their ability to actively generate electrical currents in the water and sense the electrical properties of the environment. How natural behavior contributes to this sensory system has been of interest to neuroethologists since the pioneering works of Lissmann. Here we report on a mutual modeling and experimental study of the stimuli available during active electrolocation of Gnathonemus petersii (Mormyridae). We show the validity of the model (I) by demonstrating that localized spatial patterns of object induced modulations in the electric field (electric images) are comparable to experimentally mapped 2-dimensional electric images and (II) by replicating earlier key findings showing that a normalized metric of electric image width provides an unambiguous cue for distance estimation. We then show that electric images and the distance metric vary systematically when an object is moved along the trunk. These potential ambiguities with regard to localization lead us to a spatiotemporal analysis of electric images. We introduce a new temporal metric for distance estimation that is based on the normalized spatial properties of electrical images. Finally, based on a survey of exploratory behavior, we show how objects situated at the tail, a region previously neglected, cast global electric images that extend over the whole sensory epithelium of the animals.

  13. Advancing Sustainable Materials Management: Facts and Figures Report

    EPA Pesticide Factsheets

    Each year EPA releases the Advancing Sustainable Materials Management: Facts and Figures report, formerly called Municipal Solid Waste in the United States: Facts and Figures. It includes information on Municipal Solid Waste generation, recycling, an

  14. Towards brain-activity-controlled information retrieval: Decoding image relevance from MEG signals.

    PubMed

    Kauppi, Jukka-Pekka; Kandemir, Melih; Saarinen, Veli-Matti; Hirvenkari, Lotta; Parkkonen, Lauri; Klami, Arto; Hari, Riitta; Kaski, Samuel

    2015-05-15

    We hypothesize that brain activity can be used to control future information retrieval systems. To this end, we conducted a feasibility study on predicting the relevance of visual objects from brain activity. We analyze both magnetoencephalographic (MEG) and gaze signals from nine subjects who were viewing image collages, a subset of which was relevant to a predetermined task. We report three findings: i) the relevance of an image a subject looks at can be decoded from MEG signals with performance significantly better than chance, ii) fusion of gaze-based and MEG-based classifiers significantly improves the prediction performance compared to using either signal alone, and iii) non-linear classification of the MEG signals using Gaussian process classifiers outperforms linear classification. These findings break new ground for building brain-activity-based interactive image retrieval systems, as well as for systems utilizing feedback both from brain activity and eye movements.

  15. 2',3'-cyclic nucleotide phosphohydrolase activity determined using an image analyzer detection system.

    PubMed

    Jacks, A S; Jones, M A

    1990-02-01

    The activity of 2',3'-cyclic nucleotide phosphohydrolase (CNPase) was assayed using high-performance thin-layer chromatography (HPTLC) and an image analyzer detection system. The assay system was used to study a possible inhibitory effect by aminoguanidine on CNPase specific activity. One advantage of using a fixed-time HPTLC system over a real-time spectrophotometric system for an enzyme activity study was that apparent inhibition of the enzyme due to interference of the assay system (chromophore inhibition, etc.) was avoided. In addition, due to the increased accuracy of the image analyzer over conventional methods of TLC plate analysis, a rapid and more accurate measurement of HPTLC plates was possible which required only nanomole amounts of substrate. Also, a digital image of each plate analyzed was stored indefinitely in the computer's memory for future reference. The measurements of CNPase specific activity made using this system compared favorably to those found in recent literature.

  16. Peptic ulcer perforation: sonographic imaging of active fluid leakage.

    PubMed

    Minardos, Ioannis; Ioannis, Minardos; Ziogana, Dimitra; Dimitra, Ziogana; Hristopoulos, Hristos; Hristos, Hristopoulos; Dermitzakis, Ioannis; Ioannis, Dermitzakis

    2006-01-01

    Sonography is not the method of choice for the evaluation of suspected peptic ulcer perforation (PUP). However, indirect sonographic signs and direct visualization of PUP have been reported by several authors in recent years. We report a case of an elderly woman who presented with severe abdominal pain and positive rebound sign, in whom abdominal sonography demonstrated indirect signs of PUP, the site of perforation, and active air fluid leakage through the perforated anterior prepyloric antral wall.

  17. Final Report: Imaging of Buried Nanoscale Optically Active Materials

    SciTech Connect

    Appelbaum, Ian

    2011-07-05

    This is a final report covering work done at University of Maryland to develop a Ballistic Electron Emission Luminescence (BEEL) microscope. This technique was intended to examine the carrier transport and photon emission in deeply buried optically-active layers and thereby provide a means for materials science to unmask the detailed consequences of experimentally controllable growth parameters, such as quantum dot size, statistics and orientation, and defect density and charge recombination pathways.

  18. Volcanic activity: a review for health professionals.

    PubMed Central

    Newhall, C G; Fruchter, J S

    1986-01-01

    Volcanoes erupt magma (molten rock containing variable amounts of solid crystals, dissolved volatiles, and gas bubbles) along with pulverized pre-existing rock (ripped from the walls of the vent and conduit). The resulting volcanic rocks vary in their physical and chemical characteristics, e.g., degree of fragmentation, sizes and shapes of fragments, minerals present, ratio of crystals to glass, and major and trace elements composition. Variability in the properties of magma, and in the relative roles of magmatic volatiles and groundwater in driving an eruption, determine to a great extent the type of an eruption; variability in the type of an eruption in turn influences the physical characteristics and distribution of the eruption products. The principal volcanic hazards are: ash and larger fragments that rain down from an explosion cloud (airfall tephra and ballistic fragments); flows of hot ash, blocks, and gases down the slopes of a volcano (pyroclastic flows); "mudflows" (debris flows); lava flows; and concentrations of volcanic gases in topographic depressions. Progress in volcanology is bringing improved long- and short-range forecasts of volcanic activity, and thus more options for mitigation of hazards. Collaboration between health professionals and volcanologists helps to mitigate health hazards of volcanic activity. Images FIGURE 1 FIGURE 2 FIGURE 6a-6e FIGURE 6a-6e FIGURE 8 FIGURE 9 FIGURE 10 FIGURE 11 PMID:3946726

  19. Active shape models incorporating isolated landmarks for medical image annotation

    NASA Astrophysics Data System (ADS)

    Norajitra, Tobias; Meinzer, Hans-Peter; Stieltjes, Bram; Maier-Hein, Klaus H.

    2014-03-01

    Apart from their robustness in anatomic surface segmentation, purely surface based 3D Active Shape Models lack the ability to automatically detect and annotate non-surface key points of interest. However, annotation of anatomic landmarks is desirable, as it yields additional anatomic and functional information. Moreover, landmark detection might help to further improve accuracy during ASM segmentation. We present an extension of surface-based 3D Active Shape Models incorporating isolated non-surface landmarks. Positions of isolated and surface landmarks are modeled conjoint within a point distribution model (PDM). Isolated landmark appearance is described by a set of haar-like features, supporting local landmark detection on the PDM estimates using a kNN-Classi er. Landmark detection was evaluated in a leave-one-out cross validation on a reference dataset comprising 45 CT volumes of the human liver after shape space projection. Depending on the anatomical landmark to be detected, our experiments have shown in about 1/4 up to more than 1/2 of all test cases a signi cant improvement in detection accuracy compared to the position estimates delivered by the PDM. Our results encourage further research with regard to the combination of shape priors and machine learning for landmark detection within the Active Shape Model Framework.

  20. The contribution of physical activity and media use during childhood and adolescence to adult women's body image.

    PubMed

    Slater, Amy; Tiggemann, Marika

    2006-07-01

    This study aimed to investigate the effects of both past and current physical activity and media use on women's body image. A sample of 144 female undergraduate students completed measures of current physical activity, media use and body image, as well as providing retrospective reports of their physical activity participation and media usage during childhood and adolescence. Regression analyses showed that childhood experiences of physical activity and media use predicted adult body-image concerns more strongly than current activities. It was concluded that early experiences of both physical activity and media use during childhood and adolescence play an important role in the development of adult women's body image.

  1. Tomographic image of a seismically active volcano: Mammoth Mountain, California

    USGS Publications Warehouse

    Dawson, Phillip B.; Chouet, Bernard A.; Pitt, Andrew M.

    2016-01-01

    High-resolution tomographic P wave, S wave, and VP/VS velocity structure models are derived for Mammoth Mountain, California, using phase data from the Northern California Seismic Network and a temporary deployment of broadband seismometers. An anomalous volume (5.1 × 109 to 5.9 × 1010m3) of low P and low S wave velocities is imaged beneath Mammoth Mountain, extending from near the surface to a depth of ∼2 km below sea level. We infer that the reduction in seismic wave velocities is due to the presence of CO2 distributed in oblate spheroid pores with mean aspect ratio α = 1.6 × 10−3 to 7.9 × 10−3 (crack-like pores) and mean gas volume fraction ϕ = 8.1 × 10−4 to 3.4 × 10−3. The pore density parameter κ = 3ϕ/(4πα) = na3=0.11, where n is the number of pores per cubic meter and a is the mean pore equatorial radius. The total mass of CO2 is estimated to be 4.6 × 109 to 1.9 × 1011 kg. The local geological structure indicates that the CO2 contained in the pores is delivered to the surface through fractures controlled by faults and remnant foliation of the bedrock beneath Mammoth Mountain. The total volume of CO2 contained in the reservoir suggests that given an emission rate of 500 tons day−1, the reservoir could supply the emission of CO2 for ∼25–1040 years before depletion. Continued supply of CO2 from an underlying magmatic system would significantly prolong the existence of the reservoir.

  2. Tomographic Image of a Seismically Active Volcano: Mammoth Mountain, California

    NASA Astrophysics Data System (ADS)

    Dawson, P. B.; Chouet, B. A.; Pitt, A. M.

    2015-12-01

    High-resolution tomographic P wave, S wave, and VP /VS velocity structure models are derived for Mammoth Mountain, California using phase data from the Northern California Seismic Network and a temporary deployment of broadband seismometers. An anomalous volume (˜50 km3) of low P and low S wave velocities is imaged beneath Mammoth Mountain, extending from near the surface to a depth of ˜2 km below sea level. We infer that the reduction in seismic wave velocities is primarily due to the presence of CO2 distributed in oblate-spheroid pores with mean aspect ratio α ˜8 x 10-4 (crack-like pores) and gas volume fraction φ ˜4 x 10-4. The pore density parameter κ = 3φ / (4πα) = na3 = 0.12, where n is the number of pores per cubic meter and a is the mean pore equatorial radius. The total mass of CO2 is estimated to range up to ˜1.6 x 1010 kg if the pores exclusively contain CO2, although he presence of an aqueous phase may lower this estimate by up to one order of magnitude. The local geological structure indicates that the CO2 contained in the pores is delivered to the surface through fractures controlled by faults and remnant foliation of the bedrock beneath Mammoth Mountain. The total volume of CO2 contained in the reservoir suggests that given an emission rate of 5 x 105 kg day-1, the reservoir could supply the emission of CO2 for ˜8 to ˜90 years before depletion. Continued supply of CO2 from an underlying magmatic system would significantly prolong the existence of the reservoir.

  3. Tomographic image of a seismically active volcano: Mammoth Mountain, California

    NASA Astrophysics Data System (ADS)

    Dawson, Phillip; Chouet, Bernard; Pitt, Andrew

    2016-01-01

    High-resolution tomographic P wave, S wave, and VP/VS velocity structure models are derived for Mammoth Mountain, California, using phase data from the Northern California Seismic Network and a temporary deployment of broadband seismometers. An anomalous volume (5.1 × 109 to 5.9 × 1010m3) of low P and low S wave velocities is imaged beneath Mammoth Mountain, extending from near the surface to a depth of ˜2 km below sea level. We infer that the reduction in seismic wave velocities is due to the presence of CO2 distributed in oblate spheroid pores with mean aspect ratio α = 1.6 × 10-3 to 7.9 × 10-3 (crack-like pores) and mean gas volume fraction ϕ = 8.1 × 10-4 to 3.4 × 10-3. The pore density parameter κ = 3ϕ/(4πα) = na3=0.11, where n is the number of pores per cubic meter and a is the mean pore equatorial radius. The total mass of CO2 is estimated to be 4.6 × 109 to 1.9 × 1011 kg. The local geological structure indicates that the CO2 contained in the pores is delivered to the surface through fractures controlled by faults and remnant foliation of the bedrock beneath Mammoth Mountain. The total volume of CO2 contained in the reservoir suggests that given an emission rate of 500 tons day-1, the reservoir could supply the emission of CO2 for ˜25-1040 years before depletion. Continued supply of CO2 from an underlying magmatic system would significantly prolong the existence of the reservoir.

  4. Active imaging systems to see through adverse conditions: Light-scattering based models and experimental validation

    NASA Astrophysics Data System (ADS)

    Riviere, Nicolas; Ceolato, Romain; Hespel, Laurent

    2014-10-01

    Onera, the French aerospace lab, develops and models active imaging systems to understand the relevant physical phenomena affecting these systems performance. As a consequence, efforts have been done on the propagation of a pulse through the atmosphere and on target geometries and surface properties. These imaging systems must operate at night in all ambient illumination and weather conditions in order to perform strategic surveillance for various worldwide operations. We have implemented codes for 2D and 3D laser imaging systems. As we aim to image a scene in the presence of rain, snow, fog or haze, we introduce such light-scattering effects in our numerical models and compare simulated images with measurements provided by commercial laser scanners.

  5. A novel active contour model for unsupervised low-key image segmentation

    NASA Astrophysics Data System (ADS)

    Mei, Jiangyuan; Si, Yulin; Karimi, Hamid; Gao, Huijun

    2013-06-01

    Unsupervised image segmentation is greatly useful in many vision-based applications. In this paper, we aim at the unsupervised low-key image segmentation. In low-key images, dark tone dominates the background, and gray level distribution of the foreground is heterogeneous. They widely exist in the areas of space exploration, machine vision, medical imaging, etc. In our algorithm, a novel active contour model with the probability density function of gamma distribution is proposed. The flexible gamma distribution gives a better description for both of the foreground and background in low-key images. Besides, an unsupervised curve initialization method is designed, which helps to accelerate the convergence speed of curve evolution. The experimental results demonstrate the effectiveness of the proposed algorithm through comparison with the CV model. Also, one real-world application based on our approach is described in this paper.

  6. Unsupervised Cardiac Image Segmentation via Multiswarm Active Contours with a Shape Prior

    PubMed Central

    Cruz-Aceves, I.; Avina-Cervantes, J. G.; Lopez-Hernandez, J. M.; Garcia-Hernandez, M. G.; Ibarra-Manzano, M. A.

    2013-01-01

    This paper presents a new unsupervised image segmentation method based on particle swarm optimization and scaled active contours with shape prior. The proposed method uses particle swarm optimization over a polar coordinate system to perform the segmentation task, increasing the searching capability on medical images with respect to different interactive segmentation techniques. This method is used to segment the human heart and ventricular areas from datasets of computed tomography and magnetic resonance images, where the shape prior is acquired by cardiologists, and it is utilized as the initial active contour. Moreover, to assess the performance of the cardiac medical image segmentations obtained by the proposed method and by the interactive techniques regarding the regions delineated by experts, a set of validation metrics has been adopted. The experimental results are promising and suggest that the proposed method is capable of segmenting human heart and ventricular areas accurately, which can significantly help cardiologists in clinical decision support. PMID:24198850

  7. Spatiotemporal relations of primary sensorimotor and secondary motor activation patterns mapped by NIR imaging

    PubMed Central

    Khan, Bilal; Chand, Pankaj; Alexandrakis, George

    2011-01-01

    Functional near infrared (fNIR) imaging was used to identify spatiotemporal relations between spatially distinct cortical regions activated during various hand and arm motion protocols. Imaging was performed over a field of view (FOV, 12 x 8.4 cm) including the secondary motor, primary sensorimotor, and the posterior parietal cortices over a single brain hemisphere. This is a more extended FOV than typically used in current fNIR studies. Three subjects performed four motor tasks that induced activation over this extended FOV. The tasks included card flipping (pronation and supination) that, to our knowledge, has not been performed in previous functional magnetic resonance imaging (fMRI) or fNIR studies. An earlier rise and a longer duration of the hemodynamic activation response were found in tasks requiring increased physical or mental effort. Additionally, analysis of activation images by cluster component analysis (CCA) demonstrated that cortical regions can be grouped into clusters, which can be adjacent or distant from each other, that have similar temporal activation patterns depending on whether the performed motor task is guided by visual or tactile feedback. These analyses highlight the future potential of fNIR imaging to tackle clinically relevant questions regarding the spatiotemporal relations between different sensorimotor cortex regions, e.g. ones involved in the rehabilitation response to motor impairments. PMID:22162826

  8. Electrochemiluminescence imaging for parallel single-cell analysis of active membrane cholesterol.

    PubMed

    Zhou, Junyu; Ma, Guangzhong; Chen, Yun; Fang, Danjun; Jiang, Dechen; Chen, Hong-Yuan

    2015-08-18

    Luminol electrochemiluminescence (ECL) imaging was developed for the parallel measurement of active membrane cholesterol at single living cells, thus establishing a novel electrochemical detection technique for single cells with high analysis throughput and low detection limit. In our strategy, the luminescence generated from luminol and hydrogen peroxide upon the potential was recorded in one image so that hydrogen peroxide at the surface of multiple cells could be simultaneously analyzed. Compared with the classic microelectrode array for the parallel single-cell analysis, the plat electrode only was needed in our ECL imaging, avoiding the complexity of electrode fabrication. The optimized ECL imaging system showed that hydrogen peroxide as low as 10 μM was visible and the efflux of hydrogen peroxide from cells could be determined. Coupled with the reaction between active membrane cholesterol and cholesterol oxidase to generate hydrogen peroxide, active membrane cholesterol at cells on the electrode was analyzed at single-cell level. The luminescence intensity was correlated with the amount of active membrane cholesterol, validating our system for single-cell cholesterol analysis. The relative high standard deviation on the luminescence suggested high cellular heterogeneities on hydrogen peroxide efflux and active membrane cholesterol, which exhibited the significance of single-cell analysis. This success in ECL imaging for single-cell analysis opens a new field in the parallel measurement of surface molecules at single cells.

  9. Cross-sectional imaging of functional activation in the rat somatosensory cortex with optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Aguirre, A. D.; Chen, Y.; Ruvinskaya, L.; Devor, A.; Boas, D. A.; Fujimoto, J. G.

    2005-08-01

    Simultaneous optical coherence tomography (OCT) and video microscopy were performed on the rat somatosensory cortex through a thinned skull during forepaw stimulation. Fractional change measurements in OCT images reveal a functional signal timecourse similar to well understood hemodynamic signal timecourses measured with video microscopy. The precise etiology of the observed OCT functional signal is still under investigation, but these results suggest that OCT can provide high-resolution cross-sectional images of functional neuro-vascular activation.

  10. Chronic multiscale imaging of neuronal activity in the awake common marmoset

    PubMed Central

    Yamada, Yoshiyuki; Matsumoto, Yoshifumi; Okahara, Norio; Mikoshiba, Katsuhiko

    2016-01-01

    We report a methodology to chronically record in vivo brain activity in the awake common marmoset. Over a month, stable imaging revealed macroscopic sensory maps in the somatosensory cortex and their underlying cellular activity with a high signal-to-noise ratio in the awake but not anesthetized state. This methodology is applicable to other brain regions, and will be useful for studying cortical activity and plasticity in marmosets during learning, development, and in neurological disorders. PMID:27786241

  11. [Metabolically active volumes automatic delineation methodologies in PET imaging: review and perspectives].

    PubMed

    Hatt, M; Boussion, N; Cheze-Le Rest, C; Visvikis, D; Pradier, O

    2012-02-01

    PET imaging is now considered a gold standard tool in clinical oncology, especially for diagnosis purposes. More recent applications such as therapy follow-up or tumor targeting in radiotherapy require a fast, accurate and robust metabolically active tumor volumes delineation on emission images, which cannot be obtained through manual contouring. This clinical need has sprung a large number of methodological developments regarding automatic methods to define tumor volumes on PET images. This paper reviews most of the methodologies that have been recently proposed and discusses their framework and methodological and/or clinical validation. Perspectives regarding the future work to be done are also suggested.

  12. Near-infrared microscopy imaging for quantitative analysis of active component in counterfeit imidacloprid

    NASA Astrophysics Data System (ADS)

    Huang, Yue; Cao, Jinli; Ye, Shengfeng; Duan, Jia; Wu, Lijun; Li, Qianqian; Min, Shungeng

    2012-01-01

    Near-infrared (NIR) imaging systems simultaneously record spectral and spatial information. Near-infrared imaging was applied to the identification of imidacloprid in both artificially mixed samples and commercial formulation in this study. The distributions of technical imidacloprid and additive in the heterogeneous counterfeit were obtained by the relationship imaging (RI) mode. Furthermore a series of samples which consisted of different contents of uniformly distributed imidacloprid were prepared and three data cubes were generated at each content. Extracted spectra from those images were imported to establish the partial least squares model. The model's results were: R2 99.21%, RMSEC 0.0306, RMSECV 0.0183, RMSECV/mean value 0.0348 and RSEP 0.0784. The prediction relative error of commercial formulation is 0.0680, indicating the predicted value was correlated to the real content. Lastly the chemical value reconstruction image of imidacloprid formulation products was calculated by MATLAB program. NIR microscopy imaging manifests herein its potential in qualitatively identifying the active component in counterfeit pesticide and quantifying the active component in scanned image.

  13. Emerging liquid crystal waveguide technology for low SWaP active short-wave infrared imagers

    NASA Astrophysics Data System (ADS)

    Keller, Sean D.; Uyeno, Gerald P.; Lynch, Ted; Davis, Scott R.; Rommel, Scott D.; Pino, Juan

    2015-03-01

    Raytheon's innovative active short wave infrared (SWIR) imager uses Vescent Photonic's emerging liquid crystal waveguide (LCWG) technology to continuously steer the illumination laser beam over the imager field of view (FOV). This approach instantly illuminates a very small fraction of the FOV, which significantly reduces the laser power compared to flash illumination. This reduced laser power directly leads to a reduction in the size, weight and power (SWaP) of the laser. The reduction in laser power reduces the input power and thermal rejection, which leads to additional reduction in the SWaP of the power supplies and thermal control. The high-speed steering capability of the LCWG enables the imager's SWaP reduction. The SWaP reduction is possible using either global or rolling shutter detectors. In both cases, the LCWG steers the laser beam over the entire FOV while the detector is integrating. For a rolling shutter detector, the LCWG synchronizes the steering with the rolling shutter to illuminate only regions currently integrating. Raytheon's approach enables low SWaP active SWIR imagers without compromising image quality. This paper presents the results of Raytheon's active SWIR imager demonstration including steering control and synchronization with the detector integration.

  14. Review of mesoscopic optical tomography for depth-resolved imaging of hemodynamic changes and neural activities.

    PubMed

    Tang, Qinggong; Lin, Jonathan; Tsytsarev, Vassiliy; Erzurumlu, Reha S; Liu, Yi; Chen, Yu

    2017-01-01

    Understanding the functional wiring of neural circuits and their patterns of activation following sensory stimulations is a fundamental task in the field of neuroscience. Furthermore, charting the activity patterns is undoubtedly important to elucidate how neural networks operate in the living brain. However, optical imaging must overcome the effects of light scattering in the tissue, which limit the light penetration depth and affect both the imaging quantitation and sensitivity. Laminar optical tomography (LOT) is a three-dimensional (3-D) in-vivo optical imaging technique that can be used for functional imaging. LOT can achieve both a resolution of 100 to [Formula: see text] and a penetration depth of 2 to 3 mm based either on absorption or fluorescence contrast, as well as large field-of-view and high acquisition speed. These advantages make LOT suitable for 3-D depth-resolved functional imaging of the neural functions in the brain and spinal cords. We review the basic principles and instrumentations of representative LOT systems, followed by recent applications of LOT on 3-D imaging of neural activities in the rat forepaw stimulation model and mouse whisker-barrel system.

  15. Optimization of wavelengths sets for multispectral reflectance imaging of rat olfactory bulb activation in vivo

    NASA Astrophysics Data System (ADS)

    Renaud, Rémi; Bendahmane, Mounir; Chery, Romain; Martin, Claire; Gurden, Hirac; Pain, Frederic

    2012-06-01

    Wide field multispectral imaging of light backscattered by brain tissues provides maps of hemodynamics changes (total blood volume and oxygenation) following activation. This technique relies on the fit of the reflectance images obtain at two or more wavelengths using a modified Beer-Lambert law1,2. It has been successfully applied to study the activation of several sensory cortices in the anesthetized rodent using visible light1-5. We have carried out recently the first multispectral imaging in the olfactory bulb6 (OB) of anesthetized rats. However, the optimization of wavelengths choice has not been discussed in terms of cross talk and uniqueness of the estimated parameters (blood volume and saturation maps) although this point was shown to be crucial for similar studies in Diffuse Optical Imaging in humans7-10. We have studied theoretically and experimentally the optimal sets of wavelength for multispectral imaging of rodent brain activation in the visible. Sets of optimal wavelengths have been identified and validated in vivo for multispectral imaging of the OB of rats following odor stimulus. We studied the influence of the wavelengths sets on the magnitude and time courses of the oxy- and deoxyhemoglobin concentration variations as well as on the spatial extent of activated brain areas following stimulation. Beyond the estimation of hemodynamic parameters from multispectral reflectance data, we observed repeatedly and for all wavelengths a decrease of light reflectance. For wavelengths longer than 590 nm, these observations differ from those observed in the somatosensory and barrel cortex and question the basis of the reflectance changes during activation in the OB. To solve this issue, Monte Carlo simulations (MCS) have been carried out to assess the relative contribution of absorption, scattering and anisotropy changes to the intrinsic optical imaging signals in somatosensory cortex (SsC) and OB model.

  16. Visual field and task influence illusory figure responses.

    PubMed

    Abu Bakar, Afiza; Liu, Lichan; Conci, Markus; Elliott, Mark A; Ioannides, Andreas A

    2008-11-01

    In normal viewing conditions, many objects are often hidden or occluded by others, therefore restricting the information that enters the eye. One ability that the human visual system has developed to compensate for this visual limitation is to relate the surrounding elements to globally interpret the whole scene. The appearance of illusory figures (IF) based on surrounding elements also relies on this similar function. In the present study, we hypothesized that different mechanisms may be used by the brain to process IF from the center and periphery of the visual field. We compared magnetoencephalographic responses to IFs presented at different parts of the visual field under three task loads. For central presentation, IF specific responses peaked first in V1/V2 (96-101 ms), and then in the lateral occipital complex (LOC; 132-141 ms), independent of task. For peripheral presentation, the relative modulation towards IF was markedly reduced in V1/V2 and LOC while prominent activation peaks now shifted to the Fusiform Gyrus (from 200 ms onwards). Additionally, the type of task influenced processing at early stages beginning in V1/V2 (87 ms). Our results show that retinal eccentricity plays a crucial role in IF processing: figural completion at the center of the visual field is achieved in an 'automatic' and seemingly effortless fashion whereas peripheral stimulus locations necessitate higher-order object completion stages which rely more heavily on attentional demands.

  17. 50 CFR Figure 3 to Subpart E of... - Northern Southeast Alaska Rural and Non-Rural Areas

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false Northern Southeast Alaska Rural and Non-Rural Areas 3 Figure 3 to Subpart E of Part 300 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS Pacific Halibut Fisheries Pt. 300, Subpt. E, Fig. 3 Figure...

  18. 50 CFR Figure 2 to Subpart E of... - Southern Southeast Alaska Rural and Non-Rural Areas

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 11 2013-10-01 2013-10-01 false Southern Southeast Alaska Rural and Non-Rural Areas 2 Figure 2 to Subpart E of Part 300 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS Pacific Halibut Fisheries Pt. 300, Subpt. E, Fig. 2 Figure...

  19. 50 CFR Figure 3 to Subpart E of... - Northern Southeast Alaska Rural and Non-Rural Areas

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 11 2013-10-01 2013-10-01 false Northern Southeast Alaska Rural and Non-Rural Areas 3 Figure 3 to Subpart E of Part 300 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS Pacific Halibut Fisheries Pt. 300, Subpt. E, Fig. 3 Figure...

  20. 50 CFR Figure 7 to Subpart E of... - Western and Central Alaska Rural and Non-Rural Areas

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false Western and Central Alaska Rural and Non-Rural Areas 7 Figure 7 to Subpart E of Part 300 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS Pacific Halibut Fisheries Pt. 300, Subpt. E, Fig. 7 Figure...

  1. 50 CFR Figure 2 to Subpart E of... - Southern Southeast Alaska Rural and Non-Rural Areas

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false Southern Southeast Alaska Rural and Non-Rural Areas 2 Figure 2 to Subpart E of Part 300 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS Pacific Halibut Fisheries Pt. 300, Subpt. E, Fig. 2 Figure...

  2. 50 CFR Figure 7 to Subpart E of... - Western and Central Alaska Rural and Non-Rural Areas

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 11 2013-10-01 2013-10-01 false Western and Central Alaska Rural and Non-Rural Areas 7 Figure 7 to Subpart E of Part 300 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS Pacific Halibut Fisheries Pt. 300, Subpt. E, Fig. 7 Figure...

  3. 50 CFR Figure 5 to Subpart E of... - Anchorage, Matanuska-Susitna, and Kenai Rural and Non-Rural Areas

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Anchorage, Matanuska-Susitna, and Kenai Rural and Non-Rural Areas 5 Figure 5 to Subpart E of Part 300 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS Pacific Halibut Fisheries Pt. 300, Subpt. E, Fig. 5 Figure 5 to Subpart E of Part...

  4. 50 CFR Figure 5 to Subpart E of... - Anchorage, Matanuska-Susitna, and Kenai Rural and Non-Rural Areas

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false Anchorage, Matanuska-Susitna, and Kenai Rural and Non-Rural Areas 5 Figure 5 to Subpart E of Part 300 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS Pacific Halibut Fisheries Pt. 300, Subpt. E, Fig. 5 Figure 5 to Subpart E of Part...

  5. 50 CFR Figure 5 to Subpart E of... - Anchorage, Matanuska-Susitna, and Kenai Rural and Non-Rural Areas

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 11 2012-10-01 2012-10-01 false Anchorage, Matanuska-Susitna, and Kenai Rural and Non-Rural Areas 5 Figure 5 to Subpart E of Part 300 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS Pacific Halibut Fisheries Pt. 300, Subpt. E, Fig. 5 Figure 5 to Subpart E of Part...

  6. 50 CFR Figure 5 to Subpart E of... - Anchorage, Matanuska-Susitna, and Kenai Rural and Non-Rural Areas

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 11 2013-10-01 2013-10-01 false Anchorage, Matanuska-Susitna, and Kenai Rural and Non-Rural Areas 5 Figure 5 to Subpart E of Part 300 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS Pacific Halibut Fisheries Pt. 300, Subpt. E, Fig. 5 Figure 5 to Subpart E of Part...

  7. 50 CFR Figure 5 to Subpart E of... - Anchorage, Matanuska-Susitna, and Kenai Rural and Non-Rural Areas

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 11 2014-10-01 2014-10-01 false Anchorage, Matanuska-Susitna, and Kenai Rural and Non-Rural Areas 5 Figure 5 to Subpart E of Part 300 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS Pacific Halibut Fisheries Pt. 300, Subpt. E, Fig. 5 Figure 5 to Subpart E of Part...

  8. Fast range estimation based on active range-gated imaging for coastal surveillance

    NASA Astrophysics Data System (ADS)

    Kong, Qingshan; Cao, Yinan; Wang, Xinwei; Tong, Youwan; Zhou, Yan; Liu, Yuliang

    2012-11-01

    Coastal surveillance is very important because it is useful for search and rescue, illegal immigration, or harbor security and so on. Furthermore, range estimation is critical for precisely detecting the target. Range-gated laser imaging sensor is suitable for high accuracy range especially in night and no moonlight. Generally, before detecting the target, it is necessary to change delay time till the target is captured. There are two operating mode for range-gated imaging sensor, one is passive imaging mode, and the other is gate viewing mode. Firstly, the sensor is passive mode, only capturing scenes by ICCD, once the object appears in the range of monitoring area, we can obtain the course range of the target according to the imaging geometry/projecting transform. Then, the sensor is gate viewing mode, applying micro second laser pulses and sensor gate width, we can get the range of targets by at least two continuous images with trapezoid-shaped range intensity profile. This technique enables super-resolution depth mapping with a reduction of imaging data processing. Based on the first step, we can calculate the rough value and quickly fix delay time which the target is detected. This technique has overcome the depth resolution limitation for 3D active imaging and enables super-resolution depth mapping with a reduction of imaging data processing. By the two steps, we can quickly obtain the distance between the object and sensor.

  9. Active imaging with the aids of polarization retrieve in turbid media system

    NASA Astrophysics Data System (ADS)

    Tao, Qiangqiang; Sun, Yongxuan; Shen, Fei; Xu, Qiang; Gao, Jun; Guo, Zhongyi

    2016-01-01

    We propose a novel active imaging based on the polarization retrieve (PR) method in turbid media system. In our simulations, the Monte Carlo (MC) algorithm has been used to investigate the scattering process between the incident photons and the scattering particles, and the visually concordant object but with different polarization characteristics in different regions, has been selected as the original target that is placed in the turbid media. Under linearly and circularly polarized illuminations, the simulation results demonstrate that the corresponding polarization properties can provide additional information for the imaging, and the contrast of the polarization image can also be enhanced greatly compared to the simplex intensity image in the turbid media. Besides, the polarization image adjusted by the PR method can further enhance the visibility and contrast. In addition, by PR imaging method, with the increasing particles' size in Mie's scale, the visibility can be enhanced, because of the increased forward scattering effect. In general, in the same circumstance, the circular polarization images can offer a better contrast and visibility than that of linear ones. The results indicate that the PR imaging method is more applicable to the scattering media system with relatively larger particles such as aerosols, heavy fog, cumulus, and seawater, as well as to biological tissues and blood media.

  10. Gamma activity modulated by naming of ambiguous and unambiguous images: intracranial recording

    PubMed Central

    Cho-Hisamoto, Yoshimi; Kojima, Katsuaki; Brown, Erik C; Matsuzaki, Naoyuki; Asano, Eishi

    2014-01-01

    OBJECTIVE Humans sometimes need to recognize objects based on vague and ambiguous silhouettes. Recognition of such images may require an intuitive guess. We determined the spatial-temporal characteristics of intracranially-recorded gamma activity (at 50–120 Hz) augmented differentially by naming of ambiguous and unambiguous images. METHODS We studied ten patients who underwent epilepsy surgery. Ambiguous and unambiguous images were presented during extraoperative electrocorticography recording, and patients were instructed to overtly name the object as it is first perceived. RESULTS Both naming tasks were commonly associated with gamma-augmentation sequentially involving the occipital and occipital-temporal regions, bilaterally, within 200 ms after the onset of image presentation. Naming of ambiguous images elicited gamma-augmentation specifically involving portions of the inferior-frontal, orbitofrontal, and inferior-parietal regions at 400 ms and after. Unambiguous images were associated with more intense gamma-augmentation in portions of the occipital and occipital-temporal regions. CONCLUSIONS Frontal-parietal gamma-augmentation specific to ambiguous images may reflect the additional cortical processing involved in exerting intuitive guess. Occipital gamma-augmentation enhanced during naming of unambiguous images can be explained by visual processing of stimuli with richer detail. SIGNIFICANCE Our results support the theoretical model that guessing processes in visual domain occur following the accumulation of sensory evidence resulting from the bottom-up processing in the occipital-temporal visual pathways. PMID:24815577

  11. X-ray imaging of chemically active valence electrons during a pericyclic reaction

    PubMed Central

    Bredtmann, Timm; Ivanov, Misha; Dixit, Gopal

    2014-01-01

    Time-resolved imaging of chemically active valence electron densities is a long-sought goal, as these electrons dictate the course of chemical reactions. However, X-ray scattering is always dominated by the core and inert valence electrons, making time-resolved X-ray imaging of chemically active valence electron densities extremely challenging. Here we demonstrate an effective and robust method, which emphasizes the information encoded in weakly scattered photons, to image chemically active valence electron densities. The degenerate Cope rearrangement of semibullvalene, a pericyclic reaction, is used as an example to visually illustrate our approach. Our work also provides experimental access to the long-standing problem of synchronous versus asynchronous bond formation and breaking during pericyclic reactions. PMID:25424639

  12. Imaging ERK and PKA Activation in Single Dendritic Spines during Structural Plasticity.

    PubMed

    Tang, Shen; Yasuda, Ryohei

    2017-03-22

    Extracellular signal-regulated kinase (ERK) and protein kinase A (PKA) play important roles in LTP and spine structural plasticity. While fluorescence resonance energy transfer (FRET)-based sensors for these kinases had previously been developed, they did not provide sufficient sensitivity for imaging small neuronal compartments, such as single dendritic spines in brain slices. Here we improved the sensitivity of FRET-based kinase sensors for monitoring kinase activity under two-photon fluorescence lifetime imaging microscopy (2pFLIM). Using these improved sensors, we succeeded in imaging ERK and PKA activation in single dendritic spines during structural long-term potentiation (sLTP) in hippocampal CA1 pyramidal neurons, revealing that the activation of these kinases spreads widely with length constants of more than 10 μm. The strategy for improvement of sensors used here should be applicable for developing highly sensitive biosensors for various protein kinases. VIDEO ABSTRACT.

  13. Petrological imaging of an active pluton beneath Cerro Uturuncu, Bolivia

    NASA Astrophysics Data System (ADS)

    Muir, Duncan D.; Blundy, Jon D.; Hutchinson, Michael C.; Rust, Alison C.

    2014-03-01

    Uturuncu is a dormant volcano in the Altiplano of SW Bolivia. A present day ~70 km diameter interferometric synthetic aperture radar (InSAR) anomaly roughly centred on Uturuncu's edifice is believed to be a result of magma intrusion into an active crustal pluton. Past activity at the volcano, spanning 0.89 to 0.27 Ma, is exclusively effusive and almost all lavas and domes are dacitic with phenocrysts of plagioclase, orthopyroxene, biotite, ilmenite and Ti-magnetite plus or minus quartz, and microlites of plagioclase and orthopyroxene set in rhyolitic groundmass glass. Plagioclase-hosted melt inclusions (MI) are rhyolitic with major element compositions that are similar to groundmass glasses. H2O concentrations plotted versus incompatible elements for individual samples describe a trend typical of near-isobaric, volatile-saturated crystallisation. At 870 °C, the average magma temperature calculated from Fe-Ti oxides, the average H2O of 3.2 ± 0.7 wt% and CO2 typically <160 ppm equate to MI trapping pressures of 50-120 MPa, approximately 2-4.5 km below surface. Such shallow storage precludes the role of dacite magma emplacement into pre-eruptive storage regions as being the cause of the observed InSAR anomaly. Storage pressures, whole-rock (WR) chemistry and phase assemblage are remarkably consistent across the eruptive history of the volcano, although magmatic temperatures calculated from Fe-Ti oxide geothermometry, zircon saturation thermometry using MI and orthopyroxene-melt thermometry range from 760 to 925 °C at NNO ± 1 log. This large temperature range is similar to that of saturation temperatures of observed phases in experimental data on Uturuncu dacites. The variation in calculated temperatures is attributed to piecemeal construction of the active pluton by successive inputs of new magma into a growing volume of plutonic mush. Fluctuating temperatures within the mush can account for sieve-textured cores and complex zoning in plagioclase phenocrysts

  14. Figure-ground organization based on three-dimensional symmetry

    NASA Astrophysics Data System (ADS)

    Michaux, Aaron; Jayadevan, Vijai; Delp, Edward; Pizlo, Zygmunt

    2016-11-01

    We present an approach to figure/ground organization using mirror symmetry as a general purpose and biologically motivated prior. Psychophysical evidence suggests that the human visual system makes use of symmetry in producing three-dimensional (3-D) percepts of objects. 3-D symmetry aids in scene organization because (i) almost all objects exhibit symmetry, and (ii) configurations of objects are not likely to be symmetric unless they share some additional relationship. No general purpose approach is known for solving 3-D symmetry correspondence in two-dimensional (2-D) camera images, because few invariants exist. Therefore, we present a general purpose method for finding 3-D symmetry correspondence by pairing the problem with the two-view geometry of the binocular correspondence problem. Mirror symmetry is a spatially global property that is not likely to be lost in the spatially local noise of binocular depth maps. We tested our approach on a corpus of 180 images collected indoors with a stereo camera system. K-means clustering was used as a baseline for comparison. The informative nature of the symmetry prior makes it possible to cluster data without a priori knowledge of which objects may appear in the scene, and without knowing how many objects there are in the scene.

  15. Multiplexed assays by high-content imaging for assessment of GPCR activity.

    PubMed

    Ross, D A; Lee, S; Reiser, V; Xue, J; Alves, K; Vaidya, S; Kreamer, A; Mull, R; Hudak, E; Hare, T; Detmers, P A; Lingham, R; Ferrer, M; Strulovici, B; Santini, F

    2008-07-01

    G-protein-coupled receptors (GPCR) participate in many disease pathways and represent the largest family of therapeutic targets. Thus, great investments are made to discover drugs modulating GPCR-mediated events. Among functional assays for screening GPCRs, the Transfluor imaging assay is based on redistribution of cytosolic beta-arrestin to an activated GPCR and has become widely used in high-content screening. However, assessing Transfluor alone has limitations: relying on a single mechanistic step of beta-arrestin redistribution during GPCR activation, providing no information on the stimulated GPCR's intracellular fate, and using only a single fluorescent color (green fluorescent protein). Taking full advantage of high-content imaging to screen approximately 2000 compounds, the authors multiplexed the Transfluor assay with an immunofluorescence-based quantification of GPCR internalization. This approach identified and classified 377 compounds interfering with agonist-induced activation of the Transfluor assay, receptor internalization, or both. In addition, a subset of compounds was analyzed for their performance across imaging, cell-based calcium release (fluorometric imaging plate reader [FLIPR]), and biochemical receptor binding assays (scintillation proximity assay). This indicated that the imaging assays have even better predictive power for direct inhibition of receptor binding than the FLIPR assay. In conclusion, compounds inducing unique responses can suggest novel mechanisms of action and be used as tools to study GPCR activation and internalization.

  16. Advances in multifocal methods for imaging human brain activity

    NASA Astrophysics Data System (ADS)

    Carney, Thom; Ales, Justin; Klein, Stanley A.

    2006-02-01

    The typical multifocal stimulus used in visual evoked potential (VEP) studies consists of about 60 checkerboard stimulus patches each independently contrast reversed according to an m-sequence. Cross correlation of the response (EEG, MEG, ERG, or fMRI) with the m-sequence results in a series of response kernels for each response channel and each stimulus patch. In the past the number and complexity of stimulus patches has been constrained by graphics hardware, namely the use of look-up-table (LUT) animation methods. To avoid such limitations we replaced the LUTs with true color graphic sprites to present arbitrary spatial patterns. To demonstrate the utility of the method we have recorded simultaneously from 192 cortically scaled stimulus patches each of which activate about 12mm2 of cortex in area V1. Because of the sparseness of cortical folding, very small stimulus patches and robust estimation of dipole source orientation, the method opens a new window on precise spatio-temporal mapping of early visual areas. The use of sprites also enables multiplexing stimuli such that at each patch location multiple stimuli can be presented. We have presented patterns with different orientations (or spatial frequencies) at the same patch locations but independently temporally modulated, effectively doubling the number of stimulus patches, to explore cell population interactions at the same cortical locus. We have also measured nonlinear responses to adjacent pairs of patches, thereby getting an edge response that doubles the spatial sampling density to about 1.8 mm on cortex.

  17. Noninvasive imaging of sialyltransferase activity in living cells by chemoselective recognition

    NASA Astrophysics Data System (ADS)

    Bao, Lei; Ding, Lin; Yang, Min; Ju, Huangxian

    2015-06-01

    To elucidate the biological and pathological functions of sialyltransferases (STs), intracellular ST activity evaluation is necessary. Focusing on the lack of noninvasive methods for obtaining the dynamic activity information, this work designs a sensing platform for in situ FRET imaging of intracellular ST activity and tracing of sialylation process. The system uses tetramethylrhodamine isothiocyanate labeled asialofetuin (TRITC-AF) as a ST substrate and fluorescein isothiocyanate labeled 3-aminophenylboronic acid (FITC-APBA) as the chemoselective recognition probe of sialylation product, both of which are encapsulated in a liposome vesicle for cellular delivery. The recognition of FITC-APBA to sialylated TRITC-AF leads to the FRET signal that is analyzed by FRET efficiency images. This strategy has been used to evaluate the correlation of ST activity with malignancy and cell surface sialylation, and the sialylation inhibition activity of inhibitors. This work provides a powerful noninvasive tool for glycan biosynthesis mechanism research, cancer diagnostics and drug development.

  18. Temporal muscle activation assessment by ultrasound imaging during flexor withdrawal reflex and voluntary contraction.

    PubMed

    Jose, Gomez-Tames; Shuto, Nakamura; Jose, Gonzalez; Wenwei, Yu

    2013-01-01

    Activating flexor reflexes by electrical stimulation has been used as a mechanism to initiate the swing phase or to enhance it for spinal cord injured patients. However, it is necessary to know their contraction dynamics in order to artificially induce them at the right moment of a walking cycle. This requires understanding the temporal activation pattern of both surface and deep muscles simultaneously. This study aimed at developing a system to measure and analyze the temporal activation of both surface and deep muscles during voluntary contraction and flexor reflexes (also called withdrawal reflexes) using ultrasound imaging. A set of experiments were done to verify the validity of the system, while exploring the temporal pattern of muscle activation during flexor reflexes. As a result, we were able to quantify the surface and deep muscle activity by measuring the muscle thickness, pennation angle and long-axis displacement, from the ultrasound images.

  19. Reconstruction of burst activity from calcium imaging of neuronal population via Lq minimization and interval screening

    PubMed Central

    Quan, Tingwei; Lv, Xiaohua; Liu, Xiuli; Zeng, Shaoqun

    2016-01-01

    Calcium imaging is becoming an increasingly popular technology to indirectly measure activity patterns in local neuronal networks. Based on the dependence of calcium fluorescence on neuronal spiking, two-photon calcium imaging affords single-cell resolution of neuronal population activity. However, it is still difficult to reconstruct neuronal activity from complex calcium fluorescence traces, particularly for traces contaminated by noise. Here, we describe a robust and efficient neuronal-activity reconstruction method that utilizes Lq minimization and interval screening (IS), which we refer to as LqIS. The simulation results show that LqIS performs satisfactorily in terms of both accuracy and speed of reconstruction. Reconstruction of simulation and experimental data also shows that LqIS has advantages in terms of the recall rate, precision rate, and timing error. Finally, LqIS is demonstrated to effectively reconstruct neuronal burst activity from calcium fluorescence traces recorded from large-size neuronal population. PMID:27375930

  20. A dynamic model for anomalous figures: the shape of line-induced brightness modifications.

    PubMed

    Pinna, B; Sambin, M

    1991-01-01

    It is recognized that a fundamental role in the perception of anomalous figures is played by the intensity and shape of brightness modifications induced by line ends. The aim of this work was to study the structure of these modifications experimentally, by using variously arranged dots as probes. It was thus assumed that dots can measure activations generated inside abrupt line ends. The results show distribution of activation which differs according to dot distance and angle with respect to the continuation of the line near its end. These data do not agree with the predictions of information processing models in the literature on anomalous figures, which are based on perceptually postulated figures accounting for unlikely gaps. However, they do agree with the dynamic model proposed here, which is based on the idea that certain figure characteristics, eg the differential brightness of anomalous figures, depend on activation distribution which in turn depends on the organization of the forces in play. This idea is rooted in Gestalt theory. Another model supported by our experimental data is Grossberg's neural dynamic approach. In this case too, the basic idea is that of activation distribution which depends on the interaction of complex neural networks functioning according to special algorithms.

  1. Correlation of sensorimotor activation with functional magnetic resonance imaging and magnetoencephalography in presurgical functional imaging: a spatial analysis.

    PubMed

    Kober, H; Nimsky, C; Möller, M; Hastreiter, P; Fahlbusch, R; Ganslandt, O

    2001-11-01

    In this study we investigated the spatial heterotopy of MEG and fMRI localizations after sensory and motor stimulation tasks. Both methods are frequently used to study the topology of the primary and secondary motor cortex, as well as a tool for presurgical brain mapping. fMRI was performed with a 1.5T MR system, using echo-planar imaging with a motor and a sensory task. Somatosensory and motor evoked fields were recorded with a biomagnetometer. fMRI activation was determined with a cross-correlation analysis. MEG source localization was performed with a single equivalent current dipole model and a current density localization approach. Distances between MEG and fMRI activation sites were measured within the same anatomical 3-D-MR image set. The central region could be identified by MEG and fMRI in 33 of 34 cases. However, MEG and fMRI localization results showed significantly different activation sites for the motor and sensory task with a distance of 10 and 15 mm, respectively. This reflects the different neurophysiological mechanisms: direct neuronal current flow (MEG) and secondary changes in cerebral blood flow and oxygenation level of activated versus non activated brain structures (fMRI). The result of our study has clinical implications when MEG and fMRI localizations are used for pre- and intraoperative brain mapping. Although both modalities are useful for the estimation of the motor cortex, a single modality may err in the exact topographical labeling of the motor cortex. In some unclear cases a combination of both methods should be used in order to avoid neurological deficits.

  2. Synthetic aperture microwave imaging with active probing for fusion plasma diagnostics

    SciTech Connect

    Shevchenko, Vladimir F.; Freethy, Simon J.; Huang, Billy K.

    2014-08-21

    A Synthetic Aperture Microwave Imaging (SAMI) system has been designed and built to obtain 2-D images at several frequencies from fusion plasmas. SAMI uses a phased array of linearly polarised antennas. The array configuration has been optimised to achieve maximum synthetic aperture beam efficiency. The signals received by antennas are down-converted to the intermediate frequency range and then recorded in a full vector form. Full vector signals allow beam focusing and image reconstruction in both real time and a post-processing mode. SAMI can scan over 16 pre-programmed frequencies in the range of 10-35GHz with a switching time of 300ns. The system operates in 2 different modes simultaneously: both a 'passive' imaging of plasma emission and also an 'active' imaging of the back-scattered signal of the radiation launched by one of the antennas from the same array. This second mode is similar to so-called Doppler backscattering (DBS) reflectometry with 2-D resolution of the propagation velocity of turbulent structures. Both modes of operation show good performance in fusion plasma experiments on Mega Amp Spherical Tokamak (MAST). We have obtained the first ever 2-D images of BXO mode conversion windows. With active probing, first ever turbulence velocity maps have been obtained. We present an overview of the diagnostic and discuss recent results. In contrast to quasi-optical microwave imaging systems SAMI requires neither big aperture viewing ports nor large 2-D detector arrays to achieve the desired imaging resolution. The number of effective 'pixels' of the synthesized image is proportional to the number of receiving antennas squared. Thus only a small number of optimised antennas is sufficient for the majority of applications. Possible implementation of SAMI on ITERand DEMO is discussed.

  3. Ionic contrast terahertz time resolved imaging of frog auricular heart muscle electrical activity

    NASA Astrophysics Data System (ADS)

    Masson, Jean-Baptiste; Sauviat, Martin-Pierre; Gallot, Guilhem

    2006-10-01

    The authors demonstrate the direct, noninvasive and time resolved imaging of functional frog auricular fibers by ionic contrast terahertz (ICT) near field microscopy. This technique provides quantitative, time-dependent measurement of ionic flow during auricular muscle electrical activity, and opens the way of direct noninvasive imaging of cardiac activity under stimulation. ICT microscopy technique was associated with full three-dimensional simulation enabling to measure precisely the fiber sizes. This technique coupled to waveguide technology should provide the grounds to development of advanced in vivo ion flux measurement in mammalian hearts, allowing the prediction of heart attack from change in K+ fluxes.

  4. Lag Synchronization of Switched Neural Networks via Neural Activation Function and Applications in Image Encryption.

    PubMed

    Wen, Shiping; Zeng, Zhigang; Huang, Tingwen; Meng, Qinggang; Yao, Wei

    2015-07-01

    This paper investigates the problem of global exponential lag synchronization of a class of switched neural networks with time-varying delays via neural activation function and applications in image encryption. The controller is dependent on the output of the system in the case of packed circuits, since it is hard to measure the inner state of the circuits. Thus, it is critical to design the controller based on the neuron activation function. Comparing the results, in this paper, with the existing ones shows that we improve and generalize the results derived in the previous literature. Several examples are also given to illustrate the effectiveness and potential applications in image encryption.

  5. Ka-band Dielectric Waveguide Antenna Array for Millimeter Wave Active Imaging System

    NASA Astrophysics Data System (ADS)

    Fang, Weihai; Fei, Peng; Nian, Feng; Yang, Yujie; Feng, Keming

    2014-11-01

    Ka-band compact dielectric waveguide antenna array for active imaging system is given. Antenna array with WR28 metal waveguide direct feeding is specially designed with small size, high gain, good radiation pattern, easy realization, low insertion loss and low mutual coupling. One practical antenna array for 3-D active imaging system is shown with theoretic analysis and experimental results. The mutual coupling of transmitting and receiving units is less than -30dB, the gain from 26.5GHz to 40GHz is (12-16) dB. The results in this paper provide guidelines for the designing of millimeter wave dielectric waveguide antenna array.

  6. Development of differential deposition technique for figure corrections in grazing incidence x-ray optics

    NASA Astrophysics Data System (ADS)

    Kilaru, Kiranmayee; Ramsey, Brian D.; Gubarev, Mikhail V.

    2009-08-01

    A differential deposition technique is being developed to correct the low- and mid-spatial-frequency deviations in the axial figure profile of Wolter-type grazing-incidence X-ray optics. These deviations arise due to various factors in the fabrication process and they degrade the performance of optics by limiting the achievable angular resolution. In the differential deposition technique, material is selectively deposited in varying thickness along the length of the optic to minimize these deviations, thereby improving the overall figure. The process is being tested on focusing X-ray optics being developed at MSFC for small-animal radionuclide imaging. The required spatial resolution for these optics is 100 μm (30 arc secs), which can be achieved with the electroformnickel- replication fabrication technique regularly employed at MSFC. However, by improving the figure quality of the optics through differential deposition, we aim to significantly improve the resolution beyond this value.

  7. Differential Deposition Technique for Figure Corrections in Grazing Incidence X-ray Optics

    NASA Technical Reports Server (NTRS)

    Kilaru, Kiranmayee; Ramsey, Brian D.; Gubarev, Mikhail

    2009-01-01

    A differential deposition technique is being developed to correct the low- and mid-spatial-frequency deviations in the axial figure profile of Wolter type grazing incidence X-ray optics. These deviations arise due to various factors in the fabrication process and they degrade the performance of the optics by limiting the achievable angular resolution. In the differential deposition technique, material of varying thickness is selectively deposited along the length of the optic to minimize these deviations, thereby improving the overall figure. High resolution focusing optics being developed at MSFC for small animal radionuclide imaging are being coated to test the differential deposition technique. The required spatial resolution for these optics is 100 m. This base resolution is achievable with the regular electroform-nickel-replication fabrication technique used at MSFC. However, by improving the figure quality of the optics through differential deposition, we aim at significantly improving the resolution beyond this value.

  8. Thermoelectric Figure of Merit in Anisotropic Systems

    NASA Astrophysics Data System (ADS)

    Bies, W.; Radtke, R. J.; Ehrenreich, H.

    1998-03-01

    General expressions for the electrical conductivity, thermopower, and electronic thermal conductivity are derived for anisotropic materials including their full tensorial character and properly treating the effects of the sample boundaries. The thermoelectric figure of merit ZT constructed from these quantities is proved to be maximal only when the electric field (in thermoelectric coolers) or thermal gradient (in power generators) is applied along the direction of highest conductivity. Fields applied along directions for which the conductivity tensor is non-diagonal induce transverse electric fields and thermal gradients which may be larger in magnitude than the applied fields. These fields reduce ZT below that expected from anisotropy alone. Numerical results are presented for bulk n-type Bi_2Te3 and quantum well and quantum wire geometries using semiclassical transport theory in the effective mass and relaxation time approximations. The effects of multi-valley conduction and confinement-induced splitting of the valley degeneracy are included. Surprisingly, this model predicts generally that the thermopower and hence ZT are independent of the direction of the applied fields in the limit of vanishing lattice thermal conductivity.

  9. An economics figure of merit in ALPS

    SciTech Connect

    Shatilla, Y.A.

    2000-07-01

    One of the most pressing issues facing the deregulated nuclear electric power industry is its economic competitiveness when compared to other sources of electrical power. Traditionally, finding the optimum loading pattern (LP) that meets all the safety and operational objective functions and at the same time produces the most attractive economical solutions is an iterative process. This is because (a) LP search tools usually lack the capability to generate equilibrium solutions and (b) economics objective functions are hard to include in the search process. In this paper, the Westinghouse Advanced Loading Pattern Search code (ALPS) has been demonstrated to successfully find LPs that meet user-defined operational and safety as well as economics objectives. This has been made possible by the development of TULIP language that allows the integration of external procedures into the search process of the main program, ALPS. In the example given, an economic figure of merit (EFM) has been defined and included via TULIP script into the fuel management optimization problem of a three-loop Westinghouse core operating an 18-month cycle. The LPs found by ALPS exhibit a clear trend of meeting and, in some cases, exceeding the EFM objective function defined for the ALPS search process a priori.

  10. Birth delays skew developing world's fertility figures.

    PubMed

    1999-09-01

    This article explains that birth delays skew developing world's fertility figures. When successive groups of women who have delayed childbearing start having children, the rapid fertility decline stalls. Such change in the timing of childbearing skews the total fertility rate (TFR). Analysis of the tempo component of TFR trends in Taiwan suggests that tempo effects reduced its TFR by about 10% in the late 1970s and early 1990s and by about 19% in the late 1980s. In Colombia, on the basis of increasing mean maternal age at childbirth between the 1970s and the late 1980s, tempo distortions of the TFR during the most of the 1980s seem likely. Moreover, many developing countries are now experiencing rapid fertility declines that are in part attributable to tempo changes. These changes have accelerated past fertility transitions, but they also make these countries vulnerable to future stalls in fertility when the delays in childbearing end. Since fertility reductions caused by tempo effects lead to real declines in birth rates and hence in population growth, countries that wish to reduce birth rates can take actions that encourage women to delay marriage and the onset of childbearing.

  11. Effects of image noise, respiratory motion, and motion compensation on 3D activity quantification in count-limited PET images

    NASA Astrophysics Data System (ADS)

    Siman, W.; Mawlawi, O. R.; Mikell, J. K.; Mourtada, F.; Kappadath, S. C.

    2017-01-01

    The aims of this study were to evaluate the effects of noise, motion blur, and motion compensation using quiescent-period gating (QPG) on the activity concentration (AC) distribution—quantified using the cumulative AC volume histogram (ACVH)—in count-limited studies such as 90Y-PET/CT. An International Electrotechnical Commission phantom filled with low 18F activity was used to simulate clinical 90Y-PET images. PET data were acquired using a GE-D690 when the phantom was static and subject to 1-4 cm periodic 1D motion. The static data were down-sampled into shorter durations to determine the effect of noise on ACVH. Motion-degraded PET data were sorted into multiple gates to assess the effect of motion and QPG on ACVH. Errors in ACVH at AC90 (minimum AC that covers 90% of the volume of interest (VOI)), AC80, and ACmean (average AC in the VOI) were characterized as a function of noise and amplitude before and after QPG. Scan-time reduction increased the apparent non-uniformity of sphere doses and the dispersion of ACVH. These effects were more pronounced in smaller spheres. Noise-related errors in ACVH at AC20 to AC70 were smaller (<15%) compared to the errors between AC80 to AC90 (>15%). The accuracy of ACmean was largely independent of the total count. Motion decreased the observed AC and skewed the ACVH toward lower values; the severity of this effect depended on motion amplitude and tumor diameter. The errors in AC20 to AC80 for the 17 mm sphere were  -25% and  -55% for motion amplitudes of 2 cm and 4 cm, respectively. With QPG, the errors in AC20 to AC80 of the 17 mm sphere were reduced to  -15% for motion amplitudes  <4 cm. For spheres with motion amplitude to diameter ratio  >0.5, QPG was effective at reducing errors in ACVH despite increases in image non-uniformity due to increased noise. ACVH is believed to be more relevant than mean or maximum AC to calculate tumor control and normal tissue complication probability

  12. Tracking molecular dynamics without tracking: image correlation of photo-activation microscopy

    NASA Astrophysics Data System (ADS)

    Pandžić, Elvis; Rossy, Jérémie; Gaus, Katharina

    2015-03-01

    Measuring protein dynamics in the plasma membrane can provide insights into the mechanisms of receptor signaling and other cellular functions. To quantify protein dynamics on the single molecule level over the entire cell surface, sophisticated approaches such as single particle tracking (SPT), photo-activation localization microscopy (PALM) and fluctuation-based analysis have been developed. However, analyzing molecular dynamics of fluorescent particles with intermittent excitation and low signal-to-noise ratio present at high densities has remained a challenge. We overcame this problem by applying spatio-temporal image correlation spectroscopy (STICS) analysis to photo-activated (PA) microscopy time series. In order to determine under which imaging conditions this approach is valid, we simulated PA images of diffusing particles in a homogeneous environment and varied photo-activation, reversible blinking and irreversible photo-bleaching rates. Further, we simulated data with high particle densities that populated mobile objects (such as adhesions and vesicles) that often interfere with STICS and fluctuation-based analysis. We demonstrated in experimental measurements that the diffusion coefficient of the epidermal growth factor receptor (EGFR) fused to PAGFP in live COS-7 cells can be determined in the plasma membrane and revealed differences in the time-dependent diffusion maps between wild-type and mutant Lck in activated T cells. In summary, we have developed a new analysis approach for live cell photo-activation microscopy data based on image correlation spectroscopy to quantify the spatio-temporal dynamics of single proteins.

  13. Quantum Enhanced Imaging by Entangled States

    DTIC Science & Technology

    2009-07-01

    2009 13 . SUPPLEMENTARY NOTES 14. ABSTRACT The use of entangled states in a prospective standoff imaging sensor has been explored. Specifically... 13 FIGURE 6 UNFOLDED VERSION OF SETUP FOR PSEUDO-THERMAL GHOST IMAGING. ....................... 13 FIGURE 7 SYSTEM...ALONG ATMOSPHERIC PATH. (D)-(E) FFTS OF STARTING AND FINAL DISTRIBUTIONS OF BEAM. ABSCISSA IS IN CYCLES PER METER. ......... 22 FIGURE 13 VARIANCE

  14. An active contour framework based on the Hermite transform for shape segmentation of cardiac MR images

    NASA Astrophysics Data System (ADS)

    Barba-J, Leiner; Escalante-Ramírez, Boris

    2016-04-01

    Early detection of cardiac affections is fundamental to address a correct treatment that allows preserving the patient's life. Since heart disease is one of the main causes of death in most countries, analysis of cardiac images is of great value for cardiac assessment. Cardiac MR has become essential for heart evaluation. In this work we present a segmentation framework for shape analysis in cardiac magnetic resonance (MR) images. The method consists of an active contour model which is guided by the spectral coefficients obtained from the Hermite transform (HT) of the data. The HT is used as model to code image features of the analyzed images. Region and boundary based energies are coded using the zero and first order coefficients. An additional shape constraint based on an elliptical function is used for controlling the active contour deformations. The proposed framework is applied to the segmentation of the endocardial and epicardial boundaries of the left ventricle using MR images with short axis view. The segmentation is sequential for both regions: the endocardium is segmented followed by the epicardium. The algorithm is evaluated with several MR images at different phases of the cardiac cycle demonstrating the effectiveness of the proposed method. Several metrics are used for performance evaluation.

  15. Temporal pattern of acoustic imaging noise asymmetrically modulates activation in the auditory cortex.

    PubMed

    Ranaweera, Ruwan D; Kwon, Minseok; Hu, Shuowen; Tamer, Gregory G; Luh, Wen-Ming; Talavage, Thomas M

    2016-01-01

    This study investigated the hemisphere-specific effects of the temporal pattern of imaging related acoustic noise on auditory cortex activation. Hemodynamic responses (HDRs) to five temporal patterns of imaging noise corresponding to noise generated by unique combinations of imaging volume and effective repetition time (TR), were obtained using a stroboscopic event-related paradigm with extra-long (≥27.5 s) TR to minimize inter-acquisition effects. In addition to confirmation that fMRI responses in auditory cortex do not behave in a linear manner, temporal patterns of imaging noise were found to modulate both the shape and spatial extent of hemodynamic responses, with classically non-auditory areas exhibiting responses to longer duration noise conditions. Hemispheric analysis revealed the right primary auditory cortex to be more sensitive than the left to the presence of imaging related acoustic noise. Right primary auditory cortex responses were significantly larger during all the conditions. This asymmetry of response to imaging related acoustic noise could lead to different baseline activation levels during acquisition schemes using short TR, inducing an observed asymmetry in the responses to an intended acoustic stimulus through limitations of dynamic range, rather than due to differences in neuronal processing of the stimulus. These results emphasize the importance of accounting for the temporal pattern of the acoustic noise when comparing findings across different fMRI studies, especially those involving acoustic stimulation.

  16. Active self-calibration of thoracoscopic images for assisted minimally invasive spinal surgery

    NASA Astrophysics Data System (ADS)

    Girard, Fantin; Benboujja, Fouzi; Parent, Stefan; Cheriet, Farida

    2010-02-01

    Registration of thoracoscopic images to a preoperative 3D model of the spine is a prerequisite for minimally invasive surgical guidance. We propose an active self-calibration method of thoracoscopic image sequences acquired by an angled monocular endoscope with varying focal length during minimally invasive surgery of the spine. The extrinsic parameters are updated in real time by a motion tracking system while the intrinsic parameters are determined from a set of geometrical primitives extracted from the image of the surgical instrument tracked throughout the thoracoscopic sequence. A particle filter was used for the tracking of the instrument on the image sequence that was preprocessed to detect and correct reflexions due to the light source. The proposed method requires undertaking a pure rotation of the endoscope to update the focal length and exploits the inherent temporal rigid motion of the instrument through consecutive frames. A pure rotation is achievable by undertaking a rotation of the scope cylinder with respect to the head of the camera. Therefore, the surgeon may take full advantage of an angled endoscope by adjusting focus and zoom during surgery. Simulation experiments have assessed the accuracy of the obtained parameters and the optimal number of geometrical primitives required for an active self-calibration of the angled monocular endoscope. Finally, an in vitro experiment demonstrated that 3D reconstruction of rigid structures tracked throughout a monocular thoracoscopic image sequence is feasible and its accuracy is adequate for the registration of thoracoscopic images to a preoperative MRI 3D model of the spine.

  17. Temporal pattern of acoustic imaging noise asymmetrically modulates activation in the auditory cortex

    PubMed Central

    Ranaweera, Ruwan D.; Kwon, Minseok; Hu, Shuowen; Tamer, Gregory G.; Luh, Wen-Ming; Talavage, Thomas M.

    2015-01-01

    This study investigated the hemisphere-specific effects of the temporal pattern of imaging related acoustic noise on auditory cortex activation. Hemodynamic responses (HDRs) to five temporal patterns of imaging noise corresponding to noise generated by unique combinations of imaging volume and effective repetition time (TR), were obtained using a stroboscopic event-related paradigm with extra-long (≥27.5s) TR to minimize inter-acquisition effects. In addition to confirmation that fMRI responses in auditory cortex do not behave in a linear manner, temporal patterns of imaging noise were found to modulate both the shape and spatial extent of hemodynamic responses, with classically non-auditory areas exhibiting responses to longer duration noise conditions. Hemispheric analysis revealed the right primary auditory cortex to be more sensitive than the left to the presence of imaging related acoustic noise. Right primary auditory cortex responses were significantly larger during all the conditions. This asymmetry of response to imaging related acoustic noise could lead to different baseline activation levels during acquisition schemes using short TR, inducing an observed asymmetry in the responses to an intended acoustic stimulus through limitations of dynamic range, rather than due to differences in neuronal processing of the stimulus. These results emphasize the importance of accounting for the temporal pattern of the acoustic noise when comparing findings across different fMRI studies, especially those involving acoustic stimulation. PMID:26519093

  18. Infrared-active quadruple contrast FePt nanoparticles for multiple scale molecular imaging.

    PubMed

    Chou, Shang-Wei; Liu, Chien-Liang; Liu, Tzu-Ming; Shen, Yu-Fang; Kuo, Lun-Chang; Wu, Cheng-Ham; Hsieh, Tsung-Yuan; Wu, Pei-Chun; Tsai, Ming-Rung; Yang, Che-Chang; Chang, Kai-Yao; Lu, Meng-Hua; Li, Pai-Chi; Chen, Shi-Ping; Wang, Yu-Hsin; Lu, Chen-Wen; Chen, Yi-An; Huang, Chih-Chia; Wang, Churng-Ren Chris; Hsiao, Jong-Kai; Li, Meng-Lin; Chou, Pi-Tai

    2016-04-01

    A single nanomaterial with multiple imaging contrasts and functions is highly desired for multiscale theragnosis. Herein, we demonstrate single 1-1.9 μm infrared-active FePt alloy nanoparticles (FePt NPs) offering unprecedented four-contrast-in-one molecular imaging - computed tomography (CT), magnetic resonance imaging (MRI), photoacoustic (PA) imaging, and high-order multiphoton luminescence (HOMPL) microscopy. The PA response of FePt NPs outperforms that of infrared-active gold nanorods by 3- to 5.6-fold under identical excitation fluence and particle concentrations. HOMPL (680 nm) of an isolated FePt NP renders spatial full-width-at-half-maximum values of 432 nm and 300 nm beyond the optical diffraction limit for 1230-nm and 920-nm excitation, respectively. The in vivo targeting function was successfully visualized using HOMPL, PA imaging, CT, and MRI, thereby validating FePt as a single nanomaterial system covering up to four types (Optical/PA/CT/MRI) of molecular imaging contrast, ranging from the microscopic level to whole-body scale investigation.

  19. An active contour method for bone cement reconstruction from C-arm x-ray images.

    PubMed

    Lucas, Blake C; Otake, Yoshito; Armand, Mehran; Taylor, Russell H

    2012-04-01

    A novel algorithm is presented to segment and reconstruct injected bone cement from a sparse set of X-ray images acquired at arbitrary poses. The sparse X-ray multi-view active contour (SxMAC-pronounced "smack") can 1) reconstruct objects for which the background partially occludes the object in X-ray images, 2) use X-ray images acquired on a noncircular trajectory, and 3) incorporate prior computed tomography (CT) information. The algorithm's inputs are preprocessed X-ray images, their associated pose information, and prior CT, if available. The algorithm initiates automated reconstruction using visual hull computation from a sparse number of X-ray images. It then improves the accuracy of the reconstruction by optimizing a geodesic active contour. Experiments with mathematical phantoms demonstrate improvements over a conventional silhouette based approach, and a cadaver experiment demonstrates SxMAC's ability to reconstruct high contrast bone cement that has been injected into a femur and achieve sub-millimeter accuracy with four images.

  20. Assessment of Activity of Crohn Disease by Diffusion-Weighted Magnetic Resonance Imaging.

    PubMed

    Li, Xue-Hua; Sun, Can-Hui; Mao, Ren; Zhang, Zhong-Wei; Jiang, Xiao-Song; Pui, Margaret H; Chen, Min-Hu; Li, Zi-Ping

    2015-10-01

    To assess the diagnostic efficacy of diffusion-weighted MR imaging (DWI) for evaluating inflammatory activity in patients with Crohn's disease (CD). A total of 47 CD patients underwent MR enterography (MRE) and DWI using 3 b values of 50, 400, and 800 s/mm. Apparent diffusion coefficients (ADCs) of inflamed and normal bowel wall were calculated. The conventional MRE findings and DWI signal intensities were qualitatively scored from 0 to 3. The correlation between Crohn disease activity index (CDAI) and both ADCs and magnetic resonance imaging scores was analyzed. Receiver-operating characteristic curve analysis was used to determine the diagnostic accuracy of CD activity. Of the 47 patients, 25 were active CD (CDAI≥150) and 22 were inactive (CDAI<150). Diffusion-weighted MR imaging and MRE + DWI scores of active CD were significantly higher than that of inactive CD (both P < 0.001). Apparent diffusion coefficients in inflamed segments of active CD were lower than that of inactive CD (P < 0.001). The DWI scores (r = 0.74, P < 0.001), ADCs (r = -0.71, P < 0.001), MRE scores (r = 0.54, P < 0.001), and MRE + DWI scores (r = 0.66, P < 0.001) were all correlated with CDAI. The areas under the receiver-operating characteristics curves for ADCs, DWI scores, MRE scores, and MRE + DWI scores ranged from 0.83 to 0.98. The threshold ADC value of 1.17 × 10 mm/s allowed differentiation of active from inactive CD with 100% sensitivity and 88% specificity. Diffusion-weighted MR imaging and ADC correlated with CD activity, and had excellent diagnostic accuracy for differentiating active from inactive CD.

  1. Figure-ground discrimination behavior in Drosophila. II. Visual influences on head movement behavior.

    PubMed

    Fox, Jessica L; Frye, Mark A

    2014-02-15

    Visual identification of small moving targets is a challenge for all moving animals. Their own motion generates displacement of the visual surroundings, inducing wide-field optic flow across the retina. Wide-field optic flow is used to sense perturbations in the flight course. Both ego-motion and corrective optomotor responses confound any attempt to track a salient target moving independently of the visual surroundings. What are the strategies that flying animals use to discriminate small-field figure motion from superimposed wide-field background motion? We examined how fruit flies adjust their gaze in response to a compound visual stimulus comprising a small moving figure against an independently moving wide-field ground, which they do by re-orienting their head or their flight trajectory. We found that fixing the head in place impairs object fixation in the presence of ground motion, and that head movements are necessary for stabilizing wing steering responses to wide-field ground motion when a figure is present. When a figure is moving relative to a moving ground, wing steering responses follow components of both the figure and ground trajectories, but head movements follow only the ground motion. To our knowledge, this is the first demonstration that wing responses can be uncoupled from head responses and that the two follow distinct trajectories in the case of simultaneous figure and ground motion. These results suggest that whereas figure tracking by wing kinematics is independent of head movements, head movements are important for stabilizing ground motion during active figure tracking.

  2. Surveillance of waste disposal activity at sea using satellite ocean color imagers: GOCI and MODIS

    NASA Astrophysics Data System (ADS)

    Hong, Gi Hoon; Yang, Dong Beom; Lee, Hyun-Mi; Yang, Sung Ryull; Chung, Hee Woon; Kim, Chang Joon; Kim, Young-Il; Chung, Chang Soo; Ahn, Yu-Hwan; Park, Young-Je; Moon, Jeong-Eon

    2012-09-01

    Korean Geostationary Ocean Color Imager (GOCI) and Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua observations of the variation in ocean color at the sea surface were utilized to monitor the impact of nutrient-rich sewage sludge disposal in the oligotrophic area of the Yellow Sea. MODIS revealed that algal blooms persisted in the spring annually at the dump site in the Yellow Sea since year 2000 to the present. A number of implications of using products of the satellite ocean color imagers were exploited here based on the measurements in the Yellow Sea. GOCI observes almost every hour during the daylight period, every day since June 2011. Therefore, GOCI provides a powerful tool to monitor waste disposal at sea in real time. Tracking of disposal activity from a large tanker was possible hour by hour from the GOCI timeseries images compared to MODIS. Smaller changes in the color of the ocean surface can be easily observed, as GOCI resolves images at smaller scales in space and time in comparison to polar orbiting satellites, e.g., MODIS. GOCI may be widely used to monitor various marine activities in the sea, including waste disposal activity from ships.

  3. Simple platform for chronic imaging of hippocampal activity during spontaneous behaviour in an awake mouse

    PubMed Central

    Villette, Vincent; Levesque, Mathieu; Miled, Amine; Gosselin, Benoit; Topolnik, Lisa

    2017-01-01

    Chronic electrophysiological recordings of neuronal activity combined with two-photon Ca2+ imaging give access to high resolution and cellular specificity. In addition, awake drug-free experimentation is required for investigating the physiological mechanisms that operate in the brain. Here, we developed a simple head fixation platform, which allows simultaneous chronic imaging and electrophysiological recordings to be obtained from the hippocampus of awake mice. We performed quantitative analyses of spontaneous animal behaviour, the associated network states and the cellular activities in the dorsal hippocampus as well as estimated the brain stability limits to image dendritic processes and individual axonal boutons. Ca2+ imaging recordings revealed a relatively stereotyped hippocampal activity despite a high inter-animal and inter-day variability in the mouse behavior. In addition to quiet state and locomotion behavioural patterns, the platform allowed the reliable detection of walking steps and fine speed variations. The brain motion during locomotion was limited to ~1.8 μm, thus allowing for imaging of small sub-cellular structures to be performed in parallel with recordings of network and behavioural states. This simple device extends the drug-free experimentation in vivo, enabling high-stability optophysiological experiments with single-bouton resolution in the mouse awake brain. PMID:28240275

  4. Phase-based probabilistic active contour for nerve detection in ultrasound images for regional anesthesia.

    PubMed

    Hafiane, Adel; Vieyres, Pierre; Delbos, Alain

    2014-09-01

    Ultrasound guided regional anesthesia (UGRA) is steadily growing in popularity, owing to advances in ultrasound imaging technology and the advantages that this technique presents for safety and efficiency. The aim of this work is to assist anaesthetists during the UGRA procedure by automatically detecting the nerve blocks in the ultrasound images. The main disadvantage of ultrasound images is the poor quality of the images, which are also affected by the speckle noise. Moreover, the nerve structure is not salient amid the other tissues, which makes its detection a challenging problem. In this paper we propose a new method to tackle the problem of nerve zone detection in ultrasound images. The method consists in a combination of three approaches: probabilistic, edge phase information and active contours. The gradient vector flow (GVF) is adopted as an edge-based active contour. The phase analysis of the monogenic signal is used to provide reliable edges for the GVF. Then, a learned probabilistic model reduces the false positives and increases the likelihood energy term of the target region. It yields a new external force field that attracts the active contour toward the desired region of interest. The proposed scheme has been applied to sciatic nerve regions. The qualitative and quantitative evaluations show a high accuracy and a significant improvement in performance.

  5. Simple platform for chronic imaging of hippocampal activity during spontaneous behaviour in an awake mouse.

    PubMed

    Villette, Vincent; Levesque, Mathieu; Miled, Amine; Gosselin, Benoit; Topolnik, Lisa

    2017-02-27

    Chronic electrophysiological recordings of neuronal activity combined with two-photon Ca(2+) imaging give access to high resolution and cellular specificity. In addition, awake drug-free experimentation is required for investigating the physiological mechanisms that operate in the brain. Here, we developed a simple head fixation platform, which allows simultaneous chronic imaging and electrophysiological recordings to be obtained from the hippocampus of awake mice. We performed quantitative analyses of spontaneous animal behaviour, the associated network states and the cellular activities in the dorsal hippocampus as well as estimated the brain stability limits to image dendritic processes and individual axonal boutons. Ca(2+) imaging recordings revealed a relatively stereotyped hippocampal activity despite a high inter-animal and inter-day variability in the mouse behavior. In addition to quiet state and locomotion behavioural patterns, the platform allowed the reliable detection of walking steps and fine speed variations. The brain motion during locomotion was limited to ~1.8 μm, thus allowing for imaging of small sub-cellular structures to be performed in parallel with recordings of network and behavioural states. This simple device extends the drug-free experimentation in vivo, enabling high-stability optophysiological experiments with single-bouton resolution in the mouse awake brain.

  6. DETECTING ACTIVE GALACTIC NUCLEI USING MULTI-FILTER IMAGING DATA. II. INCORPORATING ARTIFICIAL NEURAL NETWORKS

    SciTech Connect

    Dong, X. Y.; De Robertis, M. M.

    2013-10-01

    This is the second paper of the series Detecting Active Galactic Nuclei Using Multi-filter Imaging Data. In this paper we review shapelets, an image manipulation algorithm, which we employ to adjust the point-spread function (PSF) of galaxy images. This technique is used to ensure the image in each filter has the same and sharpest PSF, which is the preferred condition for detecting AGNs using multi-filter imaging data as we demonstrated in Paper I of this series. We apply shapelets on Canada-France-Hawaii Telescope Legacy Survey Wide Survey ugriz images. Photometric parameters such as effective radii, integrated fluxes within certain radii, and color gradients are measured on the shapelets-reconstructed images. These parameters are used by artificial neural networks (ANNs) which yield: photometric redshift with an rms of 0.026 and a regression R-value of 0.92; galaxy morphological types with an uncertainty less than 2 T types for z ≤ 0.1; and identification of galaxies as AGNs with 70% confidence, star-forming/starburst (SF/SB) galaxies with 90% confidence, and passive galaxies with 70% confidence for z ≤ 0.1. The incorporation of ANNs provides a more reliable technique for identifying AGN or SF/SB candidates, which could be very useful for large-scale multi-filter optical surveys that also include a modest set of spectroscopic data sufficient to train neural networks.

  7. Stimulus Selectivity of Figural Aftereffects for Faces

    ERIC Educational Resources Information Center

    Yamashita, Jill A.; Hardy, Joseph L.; De Valois, Karen K.; Webster, Michael A.

    2005-01-01

    Viewing a distorted face induces large aftereffects in the appearance of an undistorted face. The authors examined the processes underlying this adaptation by comparing how selective the aftereffects are for different dimensions of the images including size, spatial frequency content, contrast, and color. Face aftereffects had weaker selectivity…

  8. A Figure-of-Merit for Beta Cell Detector Characterization

    SciTech Connect

    Foxe, Michael P.; Miller, Brian W.; Suarez, Rey; Hayes, James C.

    2015-09-02

    In order to decrease the minimum detectable activities (MDAs) of beta-gamma radioxenon detectors, it is important to increase the ability to resolve the individual isotopes. One proposed method for doing this is to increase the energy resolution of the beta cell through the use of silicon detectors. While silicon detectors can improve the energy resolution, it is accompanied with a decrease in detection efficiency compared to plastic scintillator beta cells. Due to the uncertainty on the impact of the competing variables, we have developed a figure-of-merit (FOM) capable of determining the impact of detector parameters on the MDAs. By utilizing the FOM to analyze different detectors, we are able to directly compare current and future detectors and estimate their impact on the radioxenon MDAs.

  9. The role of suppression in figurative language comprehension✩

    PubMed Central

    Gemsbacher, Morton Ann; Robertson, Rachel R.W.

    2014-01-01

    In this paper, we describe the crucial role that suppression plays in many aspects of language comprehension. We define suppression as a general, cognitive mechanism, the purpose of which is to attenuate the interference caused by the activation of extraneous, unnecessary, or inappropriate information. We illustrate the crucial role that suppression plays in general comprehension by reviewing numerous experiments. These experiments demonstrate that suppression attenuates interference during lexical access (how word meanings are ‘accessed’), anaphoric reference (how referents for anaphors, like pronouns, are computed), cataphoric reference (how concepts that are marked by devices, such as spoken stress, gain a privileged status), syntactic parsing (how grammatical forms of sentences are decoded), and individual differences in (adult) language comprehension skill. We also review research that suggests that suppression plays a crucial role in the understanding of figurative language, in particular, metaphors, idioms, and proverbs. PMID:25520540

  10. Calcium imaging of sleep-wake related neuronal activity in the dorsal pons.

    PubMed

    Cox, Julia; Pinto, Lucas; Dan, Yang

    2016-02-25

    The dorsal pons has long been implicated in the generation of rapid eye movement (REM) sleep, but the underlying circuit mechanisms remain poorly understood. Using cell-type-specific microendoscopic Ca(2+) imaging in and near the laterodorsal tegmental nucleus, we found that many glutamatergic neurons are maximally active during REM sleep (REM-max), while the majority of GABAergic neurons are maximally active during wakefulness (wake-max). Furthermore, the activity of glutamatergic neurons exhibits a medio-lateral spatial gradient, with medially located neurons more selectively active during REM sleep.

  11. Comparison of flash and accumulation mode in range-gated active imaging

    NASA Astrophysics Data System (ADS)

    Christnacher, Frank; Laurenzis, Martin; Schertzer, Stéphane

    2013-10-01

    Range-gated active imaging has significantly been improved in the recent past. Due to the availability of high power laser diodes around 800-860 nm, it is now possible to find off-the-shelf systems working with very sensitive light intensifier and laser diodes. On the other hand, eye-safe systems working around 1.5 μm suffer from a lack of intensified sensor in the SWIR band. The only existing intensified sensors require the use of high power pulsed laser sources for the illumination. Consequently, the type of source (diode or solid-state laser) gives fundamental differences between the two types of system. The first technique which uses laser diodes, μchip or fiber lasers, is called "accumulation" imaging. These sources are characterized by a low-pulse power and high repetition rate, mostly around a few tens of kHz. Here, each image is the result of the accumulation of hundred of pulses during the frame time. The second technique which uses a solid-state laser illumination is called "flash" imaging. Here, each image is the result of a unique high power illumination of the scene at low repetition rate, mostly around the video rate. In this paper, we investigate the theoretical and practical differences between these two imaging modes and its influence on image quality, on sensitivity to day light or stray light, on fog penetration capacity, on its sensitivity to turbulences and on laser safety (NOHD). For comparative experimental purposes, we've built a range-gated active imaging system which allows the investigation of both methods. We've carried out precise comparative studies between the two acquisition methods.

  12. Acute two-photon imaging of the neurovascular unit in the cortex of active mice

    PubMed Central

    Tran, Cam Ha T.; Gordon, Grant R.

    2015-01-01

    In vivo two-photon scanning fluorescence imaging is a powerful technique to observe physiological processes from the millimeter to the micron scale in the intact animal. In neuroscience research, a common approach is to install an acute cranial window and head bar to explore neocortical function under anesthesia before inflammation peaks from the surgery. However, there are few detailed acute protocols for head-restrained and fully awake animal imaging of the neurovascular unit during activity. This is because acutely performed awake experiments are typically untenable when the animal is naïve to the imaging apparatus. Here we detail a method that achieves acute, deep-tissue two-photon imaging of neocortical astrocytes and microvasculature in behaving mice. A week prior to experimentation, implantation of the head bar alone allows mice to train for head-immobilization on an easy-to-learn air-supported ball treadmill. Following just two brief familiarization sessions to the treadmill on separate days, an acute cranial window can subsequently be installed for immediate imaging. We demonstrate how running and whisking data can be captured simultaneously with two-photon fluorescence signals with acceptable movement artifacts during active motion. We also show possible applications of this technique by (1) monitoring dynamic changes to microvascular diameter and red blood cells in response to vibrissa sensory stimulation, (2) examining responses of the cerebral microcirculation to the systemic delivery of pharmacological agents using a tail artery cannula during awake imaging, and (3) measuring Ca2+ signals from synthetic and genetically encoded Ca2+ indicators in astrocytes. This method will facilitate acute two-photon fluorescence imaging in awake, active mice and help link cellular events within the neurovascular unit to behavior. PMID:25698926

  13. Miniature microscopes for large-scale imaging of neuronal activity in freely behaving rodents.

    PubMed

    Ziv, Yaniv; Ghosh, Kunal K

    2015-06-01

    Recording neuronal activity in behaving subjects has been instrumental in studying how information is represented and processed by the brain. Recent advances in optical imaging and bioengineering have converged to enable time-lapse, cell-type specific recordings of neuronal activities from large neuronal populations in deep-brain structures of freely behaving rodents. We will highlight these advancements, with an emphasis on miniaturized integrated microscopy for large-scale imaging in freely behaving mice. This technology potentially enables studies that were difficult to perform using previous generation imaging and current electrophysiological techniques. These studies include longitudinal and population-level analyses of neuronal representations associated with different types of naturalistic behaviors and cognitive or emotional processes.

  14. Improving target discrimination ability of active polarization imagers by spectral broadening.

    PubMed

    Thomas, Lijo; Boffety, Matthieu; Goudail, François

    2015-12-28

    Active polarization imagers using liquid crystal variable retarders (LCVR) usually operate at one given wavelength for the sake of polarimetric accuracy. However, this often requires to use narrowband filters which reduces the amount of light entering the system and thus the signal-to-noise ratio. For applications where good target/background discriminability (contrast) is required rather than polarimetric accuracy, this may not be the best choice. In this Article, we address contrast optimization in the case of broadband active polarimetric imaging for target detection applications. Through numerical and experimental studies, we show that broadening the spectrum of the light entering the system can increase the contrast between two regions of a scene. Furthermore, we show that this contrast can be further increased by taking into account the spectral dependence of the scene and of the polarimetric properties of the imaging system in the optimization of the measurement procedure.

  15. Functional imaging of glucose-evoked rat islet activities using transient intrinsic optical signals

    NASA Astrophysics Data System (ADS)

    Yao, Xin-Cheng; Cui, Wan-Xing; Li, Yi-Chao; Zhang, Wei; Lu, Rong-Wen; Thompson, Anthony; Amthor, Franklin; Wang, Xu-Jing

    2012-05-01

    We demonstrate intrinsic optical signal (IOS) imaging of intact rat islet, which consists of many endocrine cells working together. A near-infrared digital microscope was employed for optical monitoring of islet activities evoked by glucose stimulation. Dynamic NIR images revealed transient IOS responses in the islet activated by low-dose (2.75 mM) and high-dose (5.5 mM) glucose stimuli. Comparative experiments and quantitative analysis indicated that both glucose metabolism and calcium/insulin dynamics might contribute to the observed IOS responses. Further investigation of the IOS imaging technology may provide a high resolution method for ex vivo functional examination of the islet, which is important for advanced study of diabetes associated islet dysfunctions and for improved quality control of donor islets for transplantation.

  16. Brain Activation during Semantic Processing in Autism Spectrum Disorders via Functional Magnetic Resonance Imaging

    ERIC Educational Resources Information Center

    Harris, Gordon J.; Chabris, Christopher F.; Clark, Jill; Urban, Trinity; Aharon, Itzhak; Steele, Shelley; McGrath, Lauren; Condouris, Karen; Tager-Flusberg, Helen

    2006-01-01

    Language and communication deficits are core features of autism spectrum disorders (ASD), even in high-functioning adults with ASD. This study investigated brain activation patterns using functional magnetic resonance imaging in right-handed adult males with ASD and a control group, matched on age, handedness, and verbal IQ. Semantic processing in…

  17. In Vivo Mesoscopic Voltage-Sensitive Dye Imaging of Brain Activation

    NASA Astrophysics Data System (ADS)

    Tang, Qinggong; Tsytsarev, Vassiliy; Frank, Aaron; Wu, Yalun; Chen, Chao-Wei; Erzurumlu, Reha S.; Chen, Yu

    2016-04-01

    Functional mapping of brain activity is important in elucidating how neural networks operate in the living brain. The whisker sensory system of rodents is an excellent model to study peripherally evoked neural activity in the central nervous system. Each facial whisker is represented by discrete modules of neurons all along the pathway leading to the neocortex. These modules are called “barrels” in layer 4 of the primary somatosensory cortex. Their location (approximately 300–500 μm below cortical surface) allows for convenient imaging of whisker-evoked neural activity in vivo. Fluorescence laminar optical tomography (FLOT) provides depth-resolved fluorescence molecular information with an imaging depth of a few millimeters. Angled illumination and detection configurations can improve both resolution and penetration depth. We applied angled FLOT (aFLOT) to record 3D neural activities evoked in the whisker system of mice by deflection of a single whisker in vivo. A 100 μm capillary and a pair of microelectrodes were inserted to the mouse brain to test the capability of the imaging system. The results show that it is possible to obtain 3D functional maps of the sensory periphery in the brain. This approach can be broadly applicable to functional imaging of other brain structures.

  18. Research on acupuncture points and cortical functional activation position in cats by infrared imaging detection

    NASA Astrophysics Data System (ADS)

    Chen, Shuwang; Sha, Zhanyou; Wang, Shuhai; Wen, Huanming

    2007-12-01

    The research of the brain cognition is mainly to find out the activation position in brain according to the stimulation at present in the world. The research regards the animals as the experimental objects and explores the stimulation response on the cerebral cortex of acupuncture. It provides a new method, which can detect the activation position on the creatural cerebral cortex directly by middle-far infrared imaging. According to the theory of local temperature situation, the difference of cortical temperature maybe associate with the excitement of cortical nerve cells, the metabolism of local tissue and the local hemal circulation. Direct naked detection of temperature variety on cerebral cortex is applied by middle and far infrared imaging technology. So the activation position is ascertained. The effect of stimulation response is superior to other indirect methods. After removing the skulls on the head, full of cerebral cortex of a cat are exposed. By observing the infrared images and measuring the temperatures of the visual cerebral cortex during the process of acupuncturing, the points are used to judge the activation position. The variety in the cortical functional sections is corresponding to the result of the acupuncture points in terms of infrared images and temperatures. According to experimental results, we know that the variety of a cortical functional section is corresponding to a special acupuncture point exactly.

  19. Assisting in Radiology/Imaging. Instructor's Guide, Student's Manual, and Student Learning Activities.

    ERIC Educational Resources Information Center

    Fair, Helena J.

    The instructor's guide, the first of three documents in this package, is designed for a course to help students who are investigating the activities within a radiology department or considering any of the imaging technologies as a career. The material is designed to relate training experience to information studied in the classroom. This…

  20. In Vivo Mesoscopic Voltage-Sensitive Dye Imaging of Brain Activation

    PubMed Central

    Tang, Qinggong; Tsytsarev, Vassiliy; Frank, Aaron; Wu, Yalun; Chen, Chao-wei; Erzurumlu, Reha S.; Chen, Yu

    2016-01-01

    Functional mapping of brain activity is important in elucidating how neural networks operate in the living brain. The whisker sensory system of rodents is an excellent model to study peripherally evoked neural activity in the central nervous system. Each facial whisker is represented by discrete modules of neurons all along the pathway leading to the neocortex. These modules are called “barrels” in layer 4 of the primary somatosensory cortex. Their location (approximately 300–500 μm below cortical surface) allows for convenient imaging of whisker-evoked neural activity in vivo. Fluorescence laminar optical tomography (FLOT) provides depth-resolved fluorescence molecular information with an imaging depth of a few millimeters. Angled illumination and detection configurations can improve both resolution and penetration depth. We applied angled FLOT (aFLOT) to record 3D neural activities evoked in the whisker system of mice by deflection of a single whisker in vivo. A 100 μm capillary and a pair of microelectrodes were inserted to the mouse brain to test the capability of the imaging system. The results show that it is possible to obtain 3D functional maps of the sensory periphery in the brain. This approach can be broadly applicable to functional imaging of other brain structures. PMID:27125318

  1. The Influence of Sentence Novelty and Figurativeness on Brain Activity

    ERIC Educational Resources Information Center

    Diaz, Michele T.; Barrett, Kyle T.; Hogstrom, Larson J.

    2011-01-01

    The predominance of the left hemisphere in language comprehension and production is well established. More recently, the right hemisphere's contribution to language has been examined. Clinical, behavioral, and neuroimaging research support the right hemisphere's involvement in metaphor processing. But, there is disagreement about whether…

  2. Real-time imaging of evoked activity in local circuits of the salamander olfactory bulb.

    PubMed

    Kauer, J S

    1988-01-14

    The encoding of olfactory information in the central nervous system (CNS) depends on spatially distributed patterns of activity generated simultaneously in many neuronal circuits. Optical neurophysiological recording permits analysis of neural activity non-invasively and with high spatial and temporal resolution. Here, a video method for imaging voltage-sensitive dye fluorescence in vivo is used to map neuronal activity in local circuits of the salamander olfactory bulb. The method permits the imaging of simultaneous ensemble transmembrane activity in real time. After electrical stimulation of the olfactory nerve, activity spreads centripetally from the sites of synaptic input to generate nonhomogeneous response patterns that are presumably mediated by local circuits within the bulbar layers. The results also show the overlapping temporal sequences of activation of cell groups in each layer. The method thus provides high resolution, sequential video images of the spatial and temporal progression of transmembrane events in neuronal circuits after afferent stimulation and offers the opportunity for studying ensemble events in other brain regions.

  3. Versatile illumination platform and fast optical switch to give standard observation camera gated active imaging capacity

    NASA Astrophysics Data System (ADS)

    Grasser, R.; Peyronneaudi, Benjamin; Yon, Kevin; Aubry, Marie

    2015-10-01

    CILAS, subsidiary of Airbus Defense and Space, develops, manufactures and sales laser-based optronics equipment for defense and homeland security applications. Part of its activity is related to active systems for threat detection, recognition and identification. Active surveillance and active imaging systems are often required to achieve identification capacity in case for long range observation in adverse conditions. In order to ease the deployment of active imaging systems often complex and expensive, CILAS suggests a new concept. It consists on the association of two apparatus working together. On one side, a patented versatile laser platform enables high peak power laser illumination for long range observation. On the other side, a small camera add-on works as a fast optical switch to select photons with specific time of flight only. The association of the versatile illumination platform and the fast optical switch presents itself as an independent body, so called "flash module", giving to virtually any passive observation systems gated active imaging capacity in NIR and SWIR.

  4. A survey of Martian dust devil activity using Mars Global Surveyor Mars Orbiter Camera images

    NASA Astrophysics Data System (ADS)

    Fisher, Jenny A.; Richardson, Mark I.; Newman, Claire E.; Szwast, Mark A.; Graf, Chelsea; Basu, Shabari; Ewald, Shawn P.; Toigo, Anthony D.; Wilson, R. John

    2005-03-01

    A survey of dust devils using the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) wide- and narrow-angle (WA and NA) images has been undertaken. The survey comprises two parts: (1) sampling of nine broad regions from September 1997 to July 2001 and (2) a focused seasonal monitoring of variability in the Amazonis region, an active dust devil site, from March 2001 to April 2004. For part 1, dust devils were identified in NA and WA images, and dust devil tracks were identified in NA images. Great spatial variability in dust devil occurrence is highlighted, with Amazonis Planitia being the most active region examined. Other active regions included Cimmerium, Sinai, and Solis. Numerous dust devil tracks, but very few dust devils, were observed in Casius. This may suggest dust devils here occur at local times other than that of the MGS orbit (~2 pm). Alternatively, variations in surface properties may affect the ability of dust devils to leave visible tracks. The seasonal campaign within Amazonis shows a relatively smooth variation of dust devil activity with season, peaking in mid northern summer and falling to zero in southern spring and summer. This pattern of activity correlates well with the boundary layer maximum depth and hence the vigor of convection. Global maps of boundary layer depth and surface temperature do not predict that Amazonis should be especially active, potentially suggesting a role for mesoscale circulations. Measurement of observed dust devils yields heights of up to 8 km and widths in excess of 0.5 km.

  5. The effect of activity outside the field of view on image quality for a 3D LSO-based whole body PET/CT scanner.

    PubMed

    Matheoud, R; Secco, C; Della Monica, P; Leva, L; Sacchetti, G; Inglese, E; Brambilla, M

    2009-10-07

    The purpose of this study was to quantify the influence of outside field of view (FOV) activity concentration (A(c)(,out)) on the noise equivalent count rate (NECR), scatter fraction (SF) and image quality of a 3D LSO whole-body PET/CT scanner. The contrast-to-noise ratio (CNR) was the figure of merit used to characterize the image quality of PET scans. A modified International Electrotechnical Commission (IEC) phantom was used to obtain SF and counting rates similar to those found in average patients. A scatter phantom was positioned at the end of the modified IEC phantom to simulate an activity that extends beyond the scanner. The modified IEC phantom was filled with (18)F (11 kBq mL(-1)) and the spherical targets, with internal diameter (ID) ranging from 10 to 37 mm, had a target-to-background ratio of 10. PET images were acquired with background activity concentrations into the FOV (A(c)(,bkg)) about 11, 9.2, 6.6, 5.2 and 3.5 kBq mL(-1). The emission scan duration (ESD) was set to 1, 2, 3 and 4 min. The tube inside the scatter phantom was filled with activities to provide A(c)(,out) in the whole scatter phantom of zero, half, unity, twofold and fourfold the one of the modified IEC phantom. Plots of CNR versus the various parameters are provided. Multiple linear regression was employed to study the effects of A(c)(,out) on CNR, adjusted for the presence of variables (sphere ID, A(c)(,bkg) and ESD) related to CNR. The presence of outside FOV activity at the same concentration as the one inside the FOV reduces peak NECR of 30%. The increase in SF is marginal (1.2%). CNR diminishes significantly with increasing outside FOV activity, in the range explored. ESD and A(c)(,out) have a similar weight in accounting for CNR variance. Thus, an experimental law that adjusts the scan duration to the outside FOV activity can be devised. Recovery of CNR loss due to an elevated A(c)(,out) activity seems feasible by modulating the ESD in individual bed positions according to A(c)(,out).

  6. Interactive Change Detection Using High Resolution Remote Sensing Images Based on Active Learning with Gaussian Processes

    NASA Astrophysics Data System (ADS)

    Ru, Hui; Yu, Huai; Huang, Pingping; Yang, Wen

    2016-06-01

    Although there have been many studies for change detection, the effective and efficient use of high resolution remote sensing images is still a problem. Conventional supervised methods need lots of annotations to classify the land cover categories and detect their changes. Besides, the training set in supervised methods often has lots of redundant samples without any essential information. In this study, we present a method for interactive change detection using high resolution remote sensing images with active learning to overcome the shortages of existing remote sensing image change detection techniques. In our method, there is no annotation of actual land cover category at the beginning. First, we find a certain number of the most representative objects in unsupervised way. Then, we can detect the change areas from multi-temporal high resolution remote sensing images by active learning with Gaussian processes in an interactive way gradually until the detection results do not change notably. The artificial labelling can be reduced substantially, and a desirable detection result can be obtained in a few iterations. The experiments on Geo-Eye1 and WorldView2 remote sensing images demonstrate the effectiveness and efficiency of our proposed method.

  7. Memory based active contour algorithm using pixel-level classified images for colon crypt segmentation.

    PubMed

    Cohen, Assaf; Rivlin, Ehud; Shimshoni, Ilan; Sabo, Edmond

    2015-07-01

    In this paper, we introduce a novel method for detection and segmentation of crypts in colon biopsies. Most of the approaches proposed in the literature try to segment the crypts using only the biopsy image without understanding the meaning of each pixel. The proposed method differs in that we segment the crypts using an automatically generated pixel-level classification image of the original biopsy image and handle the artifacts due to the sectioning process and variance in color, shape and size of the crypts. The biopsy image pixels are classified to nuclei, immune system, lumen, cytoplasm, stroma and goblet cells. The crypts are then segmented using a novel active contour approach, where the external force is determined by the semantics of each pixel and the model of the crypt. The active contour is applied for every lumen candidate detected using the pixel-level classification. Finally, a false positive crypt elimination process is performed to remove segmentation errors. This is done by measuring their adherence to the crypt model using the pixel level classification results. The method was tested on 54 biopsy images containing 4944 healthy and 2236 cancerous crypts, resulting in 87% detection of the crypts with 9% of false positive segments (segments that do not represent a crypt). The segmentation accuracy of the true positive segments is 96%.

  8. Magnetic resonance imaging of the initial active stage of equine laminitis at 4.7 T.

    PubMed

    Arble, Jason B; Mattoon, John S; Drost, Wm Tod; Weisbrode, Steven E; Wassenaar, Peter A; Pan, Xueliang; Hunt, Robert J; Belknap, James K

    2009-01-01

    Equine laminitis is a severely debilitating disease. There is a poor understanding of the underlying pathophysiology, and traditional imaging modalities have limited diagnostic capacity. High field strength magnetic resonance (MR) imaging allows direct visualization of the laminae, which other modalities do not. This would prove useful both in assessment of clinical patients and in further investigation into the pathophysiology of the disease. The objective of this study was to characterize the anatomic changes within the equine foot associated with the initial active stage of laminitis. Images obtained using a 4.7 T magnet were compared with digital radiographs using histologic diagnosis as the reference standard. Objective measurements and subjective evaluation for both modalities were evaluated for the ability to predict the histologic diagnosis in horses with clinical signs of laminitis as well as in clinically normal horses and horses that were in a population at risk for developing laminitis. Signal intensity and architectural changes within the corium and laminae were readily seen at 4.7 T, and there was a strong association with the histologic diagnosis of active laminitis. Measurements obtained with MR imaging were more sensitive and specific predictors of laminitis than those obtained radiographically. Subjective evaluation with MR imaging was more sensitive than with radiography and should become more specific with greater understanding of normal anatomy.

  9. The Stellar Imager (SI) - A Mission to Resolve Stellar Surfaces, Interiors, and Magnetic Activity

    NASA Astrophysics Data System (ADS)

    Carpenter, K. G.; Schrijver, C. J.; Karovska, M.; Si Vision Mission Team

    2009-09-01

    The Stellar Imager (SI) is a UV/Optical, Space-Based Interferometer designed to enable 0.1 milli-arcsecond (mas) spectral imaging of stellar surfaces and, via asteroseismology, stellar interiors and of the Universe in general. The ultra-sharp images of the Stellar Imager will revolutionize our view of many dynamic astrophysical processes by transforming point sources into extended sources, and snapshots into evolving views. SI's science focuses on the role of magnetism in the Universe, particularly on magnetic activity on the surfaces of stars like the Sun. SI's prime goal is to enable long-term forecasting of solar activity and the space weather that it drives. SI will also revolutionize our understanding of the formation of planetary systems, of the habitability and climatology of distant planets, and of many magneto-hydrodynamically controlled processes in the Universe. SI is included as a ``Flagship and Landmark Discovery Mission'' in the 2005 NASA Sun Solar System Connection (SSSC) Roadmap and as a candidate for a ``Pathways to Life Observatory'' in the NASA Exploration of the Universe Division (EUD) Roadmap (May, 2005). In this paper we discuss the science goals and technology needs of, and the baseline design for, the SI Mission (http://hires.gsfc.nasa.gov/si/) and its ability to image the Biggest, Baddest, Coolest Stars.

  10. The Stellar Imager (SI) - A Mission to Resolve Stellar Surfaces, Interiors, and Magnetic Activity

    NASA Technical Reports Server (NTRS)

    Carpenter, Kenneth; Schrijver, Carolus J.; Karovska, Margarita

    2007-01-01

    The Stellar Imager (SI) is a UV/Optical, Space-Based Interferometer designed to enable 0.1 milli-arcsecond (mas) spectral imaging of stellar surfaces and, via asteroseismology, stellar interiors and of the Universe in general. The ultra-sharp images of the Stellar Imager will revolutionize our view of many dynamic astrophysical processes by transforming point sources into extended sources, and snapshots into evolving views. SI's science focuses on the role of magnetism in the Universe, particularly on magnetic activity on the surfaces of stars like the Sun. SI's prime goal is to enable long-term forecasting of solar activity and the space weather that it drives. SI will also revolutionize our understanding of the formation of planetary systems, of the habitability and climatology of distant planets, and of many magneto-hydrodynamically controlled processes in the Universe. SI is included as a 'Flagship and Landmark Discovery Mission' in the 2005 NASA Sun Solar System Connection (SSSC) Roadmap and as a candidate for a 'Pathways to Life Observatory' in the NASA Exploration of the Universe Division (EUD) Roadmap (May, 2005). In this paper we discuss the science goals and technology needs of, and the baseline design for, the SI Mission (http://hires.gsfc.nasa.gov/si/) its ability to image the 'Biggest, Baddest, Coolest Stars'.

  11. Beyond captions: linking figures with abstract sentences in biomedical articles.

    PubMed

    Bockhorst, Joseph P; Conroy, John M; Agarwal, Shashank; O'Leary, Dianne P; Yu, Hong

    2012-01-01

    Although figures in scientific articles have high information content and concisely communicate many key research findings, they are currently under utilized by literature search and retrieval systems. Many systems ignore figures, and those that do not typically only consider caption text. This study describes and evaluates a fully automated approach for associating figures in the body of a biomedical article with sentences in its abstract. We use supervised methods to learn probabilistic language models, hidden Markov models, and conditional random fields for predicting associations between abstract sentences and figures. Three kinds of evidence are used: text in abstract sentences and figures, relative positions of sentences and figures, and the patterns of sentence/figure associations across an article. Each information source is shown to have predictive value, and models that use all kinds of evidence are more accurate than models that do not. Our most accurate method has an F1-score of 69% on a cross-validation experiment, is competitive with the accuracy of human experts, has significantly better predictive accuracy than state-of-the-art methods and enables users to access figures associated with an abstract sentence with an average of 1.82 fewer mouse clicks. A user evaluation shows that human users find our system beneficial. The system is available at http://FigureItOut.askHERMES.org.

  12. Higher-order figure discrimination in fly and human vision.

    PubMed

    Aptekar, Jacob W; Frye, Mark A

    2013-08-19

    Visually-guided animals rely on their ability to stabilize the panorama and simultaneously track salient objects, or figures, that are distinct from the background in order to avoid predators, pursue food resources and mates, and navigate spatially. Visual figures are distinguished by luminance signals that produce coherent motion cues as well as more enigmatic 'higher-order' statistical features. Figure discrimination is thus a complex form of motion vision requiring specialized neural processing. In this minireview, we will highlight recent advances in understanding the perceptual, behavioral, and neurophysiological basis of higher-order figure detection in flies, much of which is grounded in the historical perspective and mechanistic underpinnings of human psychophysics.

  13. Surface reconstruction, figure-ground modulation, and border-ownership.

    PubMed

    Jeurissen, Danique; Self, Matthew W; Roelfsema, Pieter R

    2013-01-01

    The Differentiation-Integration for Surface Completion (DISC) model aims to explain the reconstruction of visual surfaces. We find the model a valuable contribution to our understanding of figure-ground organization. We point out that, next to border-ownership, neurons in visual cortex code whether surface elements belong to a figure or the background and that this is influenced by attention. We furthermore suggest that there must be strong links between object recognition and figure-ground assignment in order to resolve the status of interior contours. Incorporation of these factors in neurocomputational models will further improve our understanding of surface reconstruction, figure-ground organization, and border-ownership.

  14. BOOK REVIEW: Relativistic Figures of Equilibrium

    NASA Astrophysics Data System (ADS)

    Mars, M.

    2009-08-01

    Compact fluid bodies in equilibrium under its own gravitational field are abundant in the Universe and a proper treatment of them can only be carried out using the full theory of General Relativity. The problem is of enormous complexity as it involves two very different regimes, namely the interior and the exterior of the fluid, coupled through the surface of the body. This problem is very challenging both from a purely theoretical point of view, as well as regarding the obtaining of realistic models and the description of their physical properties. It is therefore an excellent piece of news that the book 'Relativistic Figures of Equilibrium' by R Meinel, M Ansorg, A Kleinwächter, G Neugebauer and D Petroff has been recently published. This book approaches the topic in depth and its contents will be of interest to a wide range of scientists working on gravitation, including theoreticians in general relativity, mathematical physicists, astrophysicists and numerical relativists. This is an advanced book that intends to present some of the present-day results on this topic. The most basic results are presented rather succinctly, and without going into the details, of their derivations. Although primarily not intended to serve as a textbook, the presentation is nevertheless self-contained and can therefore be of interest both for experts on the field as well as for anybody wishing to learn more about rotating self-gravitating compact bodies in equilibrium. It should be remarked, however, that this book makes a rather strong selection of topics and concentrates fundamentally on presenting the main results obtained by the authors during their research in this field. The book starts with a chapter where the fundamental aspects of rotating fluids in equilibrium, including its thermodynamic properties, are summarized. Of particular interest are the so-called mass-shedding limit, which is the limit where the body is rotating so fast that it is on the verge of starting

  15. Dual Gated Imaging system for Enhanced Fluorescent Diagnostics Measurements

    DTIC Science & Technology

    1992-03-13

    Imaging: An Approach for Fuel Equivalence Ratio Imaging", Applied Spectroscopy , 45, 938 (1991). 2. R.M. Ballew and J.N. Demas, "An Error Analysis of...and S.C. Yang, Applied Spectroscopy , 39, 266 (1985). of Figures Block diagram of dual gated imaging system VII. List Figure 1 Figure 2

  16. Health Perceptions, Self and Body Image, Physical Activity and Nutrition among Undergraduate Students in Israel

    PubMed Central

    Korn, Liat; Gonen, Ester; Shaked, Yael; Golan, Moria

    2013-01-01

    Purpose This study examines health perceptions, self and body image, physical exercise and nutrition among undergraduate students. Methods A structured, self-reported questionnaire was administered to more than 1500 students at a large academic institute in Israel. The study population was heterogenic in both gender and fields of academic study. Results High correlations between health perceptions, appropriate nutrition, and positive self and body image were found. The relationships between these variables differed between the subpopulation in the sample and the different genders. Engagement in physical exercise contributed to positive body image and positive health perceptions more than engagement in healthy nutrition. Nutrition students reported higher frequencies of positive health perceptions, positive self and body image and higher engagement in physical exercise in comparison to all other students in the sample. Conclusions This study suggests, as have many before, that successful health promotion policy should reflect a collectivist rather than an individualist ethos by providing health prerequisites through a public policy of health-promotion, where the academic settings support a healthy lifestyle policy, by increasing availability of a healthy, nutritious and varied menu in the cafeterias, and offering students various activities that enhance healthy eating and exercise. Implications and contribution This study examined health perceptions, self-image, physical exercise and nutrition among undergraduate students and found high correlations between these topics. Nutrition students reported higher frequencies of positive health perceptions, and positive self and body image and engaged more in physical exercise when compared with all other students in the sample. PMID:23516503

  17. High-contrast active cavitation imaging technique based on multiple bubble wavelet transform.

    PubMed

    Lu, Shukuan; Xu, Shanshan; Liu, Runna; Hu, Hong; Wan, Mingxi

    2016-08-01

    In this study, a unique method that combines the ultrafast active cavitation imaging technique with multiple bubble wavelet transform (MBWT) for improving cavitation detection contrast was presented. The bubble wavelet was constructed by the modified Keller-Miksis equation that considered the mutual effect among bubbles. A three-dimensional spatial model was applied to simulate the spatial distribution of multiple bubbles. The effects of four parameters on the signal-to-noise ratio (SNR) of cavitation images were evaluated, including the following: initial radii of bubbles, scale factor in the wavelet transform, number of bubbles, and the minimum inter-bubble distance. And the other two spatial models and cavitation bubble size distributions were introduced in the MBWT method. The results suggested that in the free-field experiments, the averaged SNR of images acquired by the MBWT method was improved by 7.16 ± 0.09 dB and 3.14 ± 0.14 dB compared with the values of images acquired by the B-mode and single bubble wavelet transform (SBWT) methods. In addition, in the tissue experiments, the averaged cavitation-to-tissue ratio of cavitation images acquired by the MBWT method was improved by 4.69 ± 0.25 dB and 1.74± 0.29 dB compared with that of images acquired by B-mode and SBWT methods.

  18. Image patch analysis of sunspots and active regions. I. Intrinsic dimension and correlation analysis

    NASA Astrophysics Data System (ADS)

    Moon, Kevin R.; Li, Jimmy J.; Delouille, Véronique; De Visscher, Ruben; Watson, Fraser; Hero, Alfred O.

    2016-01-01

    Context. The flare productivity of an active region is observed to be related to its spatial complexity. Mount Wilson or McIntosh sunspot classifications measure such complexity but in a categorical way, and may therefore not use all the information present in the observations. Moreover, such categorical schemes hinder a systematic study of an active region's evolution for example. Aims: We propose fine-scale quantitative descriptors for an active region's complexity and relate them to the Mount Wilson classification. We analyze the local correlation structure within continuum and magnetogram data, as well as the cross-correlation between continuum and magnetogram data. Methods: We compute the intrinsic dimension, partial correlation, and canonical correlation analysis (CCA) of image patches of continuum and magnetogram active region images taken from the SOHO-MDI instrument. We use masks of sunspots derived from continuum as well as larger masks of magnetic active regions derived from magnetogram to analyze separately the core part of an active region from its surrounding part. Results: We find relationships between the complexity of an active region as measured by its Mount Wilson classification and the intrinsic dimension of its image patches. Partial correlation patterns exhibit approximately a third-order Markov structure. CCA reveals different patterns of correlation between continuum and magnetogram within the sunspots and in the region surrounding the sunspots. Conclusions: Intrinsic dimension has the potential to distinguish simple from complex active regions. These results also pave the way for patch-based dictionary learning with a view toward automatic clustering of active regions.

  19. Highly Sensitive Detection of Minimal Cardiac Ischemia using Positron Emission Tomography Imaging of Activated Platelets

    PubMed Central

    Ziegler, Melanie; Alt, Karen; Paterson, Brett M.; Kanellakis, Peter; Bobik, Alex; Donnelly, Paul S.; Hagemeyer, Christoph E.; Peter, Karlheinz

    2016-01-01

    A reliable method for the diagnosis of minimal cardiac ischemia would meet a strong demand for the sensitive diagnosis of coronary artery disease in cardiac stress testing and risk stratification in patients with chest pain but unremarkable ECGs and biomarkers. We hypothesized that platelets accumulate early on in ischemic myocardium and a newly developed technology of non-invasive molecular PET imaging of activated platelets can thus detect minimal degrees of myocardial ischemia. To induce different degrees of minimal cardiac ischemia, the left anterior descending artery (LAD) was ligated for 10, 20 or 60 min. Mice were injected with a newly generated scFvanti-GPIIb/IIIa-64CuMeCOSar radiotracer, composed of a single-chain antibody that only binds to activated integrin GPIIb/IIIa (αIIbβIII) and thus to activated platelets, and a sarcophagine cage MeCOSar complexing the long half-life PET tracer copper-64. A single PET/CT scan was performed. Evans Blue/TTC staining to detect necrosis as well as classical serological biomarkers like Troponin I and heart-type fatty acid-binding protein (H-FABP) were negative, whereas PET imaging of activated platelets was able to detect small degrees of ischemia. Taken together, molecular PET imaging of activated platelets represents a unique and highly sensitive method to detect minimal cardiac ischemia. PMID:27909290

  20. Imaging the spatiotemporal organization of neural activity in the developing spinal cord.

    PubMed

    O'Donovan, Michael J; Bonnot, Agnes; Mentis, George Z; Arai, Yoshi; Chub, Nikolai; Shneider, Neil A; Wenner, Peter

    2008-05-01

    In this review, we discuss the use of imaging to visualize the spatiotemporal organization of network activity in the developing spinal cord of the chick embryo and the neonatal mouse. We describe several different methods for loading ion- and voltage-sensitive dyes into spinal neurons and consider the advantages and limitations of each one. We review work in the chick embryo, suggesting that motoneurons play a critical role in the initiation of each cycle of spontaneous network activity and describe how imaging has been used to identify a class of spinal interneuron that appears to be the avian homolog of mammalian Renshaw cells or 1a-inhibitory interneurons. Imaging of locomotor-like activity in the neonatal mouse revealed a wave-like activation of motoneurons during each cycle of discharge. We discuss the significance of this finding and its implications for understanding how locomotor-like activity is coordinated across different segments of the cord. In the last part of the review, we discuss some of the exciting new prospects for the future.

  1. Protease-Activated Pore-Forming Peptides for the Treatment and Imaging of Prostate Cancer

    PubMed Central

    LeBeau, Aaron M.; Denmeade, Samuel R.

    2015-01-01

    A common hallmark of cancers with highly aggressive phenotypes is increased proteolysis in the tumor and the surrounding microenvironment. Prostate cancer has a number of proteases uniquely associated with it that may play various important roles in disease progression. In this report, we utilize the peritumoral proteolytic activity of prostate cancer to activate engineered peptide constructs for the treatment and noninvasive imaging of prostate cancer. Using a modular "propeptide" approach, a cationic diastereomeric pore-forming peptide domain was linked to an inactivating acidic peptide domain. The inactivating acidic peptide domain was engineered to be a cleavable substrate for the secreted serine protease prostate-specific antigen (PSA) or the transmembrane metalloprotease prostate-specific membrane antigen (PSMA). The propeptides were then evaluated in a direct comparison study. Both the PSA and PSMA activated propeptides were found to be cytotoxic to prostate cancer cells in vitro. In vivo, however, treatment of LNCaP and CWR22Rv1 xenografts with the PSMA propeptide resulted in a pronounced cytostatic effect when compared with xenografts treated with the PSA propeptide or the cationic diastereomeric peptide alone. The PSMA activated propeptide also proved to be an effective optical imaging probe in vivo when labeled with a near-infrared fluorophore. These data suggest that protease-activated pore-forming peptides could potentially be used for both imaging and treating prostate cancer. PMID:25537662

  2. Comparison of the Extended Kalman Filter and the Unscented Kalman Filter for Magnetocardiography activation time imaging

    NASA Astrophysics Data System (ADS)

    Ahrens, H.; Argin, F.; Klinkenbusch, L.

    2013-07-01

    The non-invasive and radiation-free imaging of the electrical activity of the heart with Electrocardiography (ECG) or Magnetocardiography (MCG) can be helpful for physicians for instance in the localization of the origin of cardiac arrhythmia. In this paper we compare two Kalman Filter algorithms for the solution of a nonlinear state-space model and for the subsequent imaging of the activation/depolarization times of the heart muscle: the Extended Kalman Filter (EKF) and the Unscented Kalman Filter (UKF). The algorithms are compared for simulations of a (6×6) magnetometer array, a torso model with piecewise homogeneous conductivities, 946 current dipoles located in a small part of the heart (apex), and several noise levels. It is found that for all tested noise levels the convergence of the activation times is faster for the UKF.

  3. Figures and First Years: Examining first-year Calculus I student ability to incorporate figures into technical reports

    NASA Astrophysics Data System (ADS)

    Antonacci, Nathan; Rogers, Michael; Pfaff, Thomas

    This three-year study focused on first-year Calculus I students and their abilities to incorporate figures into technical reports. Students were handed guidelines as part of their Multidisciplinary Sustainability Education Module meant to aid them in crafting effective figures. Figure-specific questionnaires were added in the class to gain insight into the quantitative literacy skills students possessed both before starting their course and after its completion. Reviews of the figures in 78 technical reports written by 106 students showed repeated failure to refer to figures in discussion sections and use them in evidence-based arguments. Analysis of quantitative literacy skills revealed that the students could both read and interpret figures, suggesting that issues with literacy were not the main contributor to the sub-par graphs.

  4. Fluorescence imaging of local membrane electric fields during the excitation of single neurons in culture.

    PubMed Central

    Gogan, P; Schmiedel-Jakob, I; Chitti, Y; Tyc-Dumont, S

    1995-01-01

    The spatial distribution of depolarized patches of membrane during the excitation of single neurons in culture has been recorded with a high spatial resolution (1 micron2/pixel) imaging system based on a liquid-nitrogen-cooled astronomical camera mounted on an inverted microscope. Images were captured from rat nodose neurons stained with the voltage-sensitive dye RH237. Conventional intracellular microelectrode recordings were made in synchrony with the images. During an action potential the fluorescence changes occurred in localized, unevenly distributed membrane areas, which formed clusters of depolarized sites of different sizes and intensities. When fast conductances were blocked by the addition of tetrodotoxin, a reduction in the number and the intensities of the depolarized sites was observed. The blockade by tetrodotoxin of voltage-clamped neurons also reduced the number of depolarized sites, although the same depolarizing voltage step was applied. Similarly, when a voltage-clamped neuron was depolarized by a constant-amplitude voltage step, the number of depolarized sites varied according to the degree of activation of the voltage-sensitive channels, which was modified by changing the holding potential. These results suggest that the spatial patterns of depolarization observed during excitation are related to the operations of ionic channels in the membrane. Images FIGURE 1 FIGURE 2 FIGURE 4 FIGURE 5 FIGURE 6 FIGURE 7 PMID:8527643

  5. Active learning for convenient annotation and classification of secondary ion mass spectrometry images.

    PubMed

    Hanselmann, Michael; Röder, Jens; Köthe, Ullrich; Renard, Bernhard Y; Heeren, Ron M A; Hamprecht, Fred A

    2013-01-02

    Digital staining for the automated annotation of mass spectrometry imaging (MSI) data has previously been achieved using state-of-the-art classifiers such as random forests or support vector machines (SVMs). However, the training of such classifiers requires an expert to label exemplary data in advance. This process is time-consuming and hence costly, especially if the tissue is heterogeneous. In theory, it may be sufficient to only label a few highly representative pixels of an MS image, but it is not known a priori which pixels to select. This motivates active learning strategies in which the algorithm itself queries the expert by automatically suggesting promising candidate pixels of an MS image for labeling. Given a suitable querying strategy, the number of required training labels can be significantly reduced while maintaining classification accuracy. In this work, we propose active learning for convenient annotation of MSI data. We generalize a recently proposed active learning method to the multiclass case and combine it with the random forest classifier. Its superior performance over random sampling is demonstrated on secondary ion mass spectrometry data, making it an interesting approach for the classification of MS images.

  6. Short cavity active mode locking fiber laser for optical sensing and imaging

    NASA Astrophysics Data System (ADS)

    Lee, Hwi Don; Han, Ga Hee; Jeong, Syung Won; Jeong, Myung Yung; Kim, Chang-Seok; Shin, Jun Geun; Lee, Byeong Ha; Eom, Tae Joong

    2014-05-01

    We demonstrate a highly linear wavenumber- swept active mode locking (AML) fiber laser for optical sensing and imaging without any wavenumber-space resampling process. In this all-electric AML wavenumber-swept mechanism, a conventional wavelength selection filter is eliminated and, instead, the suitable programmed electric modulation signal is directly applied to the gain medium. Various types of wavenumber (or wavelength) tunings can be implemented because of the filter-less cavity configuration. Therefore, we successfully demonstrate a linearly wavenumber-swept AML fiber laser with 26.5 mW of output power to obtain an in-vivo OCT image at the 100 kHz swept rate.

  7. Development history of real-time imaging active gated TV: 1970 to present

    NASA Astrophysics Data System (ADS)

    Shimer, Steven E.; Baker, Bob; Torgerson, John

    1999-07-01

    This paper discusses the development history of real-time imaging active gated TV sensors from 1970 to present at Ball Aerospace and Technologies Corp. A number of AGTV systems are covered including: Video Imaging Detection and Ranging which was developed for hydrofoils in Southeast Asia, AC- 130U gunship, Airborne Laser-Based Enhanced Detection and Observation System search and rescue system for the Canadian Government, and several long-range surveillance systems. Technology developments related to sensor and illuminator over the past 3 decades are also discussed.

  8. Development of CMOS Active Pixel Image Sensors for Low Cost Commercial Applications

    NASA Technical Reports Server (NTRS)

    Gee, R.; Kemeny, S.; Kim, Q.; Mendis, S.; Nakamura, J.; Nixon, R.; Ortiz, M.; Pain, B.; Staller, C.; Zhou, Z; Fossum, E.

    1994-01-01

    JPL, under sponsorship from the NASA Office of Advanced Concepts and Technology, has been developing a second-generation solid-state image sensor technology. Charge-coupled devices (CCD) are a well-established first generation image sensor technology. For both commercial and NASA applications, CCDs have numerous shortcomings. In response, the active pixel sensor (APS) technology has been under research. The major advantages of APS technology are the ability to integrate on-chip timing, control, signal-processing and analog-to-digital converter functions, reduced sensitivity to radiation effects, low power operation, and random access readout.

  9. Exploration of amphoteric and negative refraction imaging of acoustic sources via active metamaterials

    NASA Astrophysics Data System (ADS)

    Wen, Jihong; Shen, Huijie; Yu, Dianlong; Wen, Xisen

    2013-11-01

    The present work describes the design of three flat superlens structures for acoustic source imaging and explores an active acoustic metamaterial (AAM) to realise such a design. The first two lenses are constructed via the coordinate transform method (CTM), and their constituent materials are anisotropic. The third lens consists of a material that has both a negative density and a negative bulk modulus. In these lenses, the quality of the images is “clear” and sharp; thus, the diffraction limit of classical lenses is overcome. Finally, a multi-control strategy is developed to achieve the desired parameters and to eliminate coupling effects in the AAM.

  10. Nanometric resolution magnetic resonance imaging methods for mapping functional activity in neuronal networks.

    PubMed

    Boretti, Albert; Castelletto, Stefania

    2016-01-01

    This contribution highlights and compares some recent achievements in the use of k-space and real space imaging (scanning probe and wide-filed microscope techniques), when applied to a luminescent color center in diamond, known as nitrogen vacancy (NV) center. These techniques combined with the optically detected magnetic resonance of NV, provide a unique platform to achieve nanometric magnetic resonance imaging (MRI) resolution of nearby nuclear spins (known as nanoMRI), and nanometric NV real space localization. •Atomic size optically detectable spin probe.•High magnetic field sensitivity and nanometric resolution.•Non-invasive mapping of functional activity in neuronal networks.

  11. The relationship between bilingualism and selective attention in young adults: Evidence from an ambiguous figures task.

    PubMed

    Chung-Fat-Yim, Ashley; Sorge, Geoff B; Bialystok, Ellen

    2017-03-01

    Previous research has shown that bilinguals outperform monolinguals on a variety of tasks that have been described as involving executive functioning, but the precise mechanism for those effects or a clear definition for "executive function" is unknown. This uncertainty has led to a number of studies for which no performance difference between monolingual and bilingual adults has been detected. One approach to clarifying these issues comes from research with children showing that bilinguals were more able than their monolingual peers to perceive both interpretations of an ambiguous figure, an ability that is more tied to a conception of selective attention than to specific components of executive function. The present study extends this notion to adults by assessing their ability to see the alternative image in an ambiguous figure. Bilinguals performed this task more efficiently than monolinguals by requiring fewer cues to identify the second image. This finding has implications for the role of selective attention in performance differences between monolinguals and bilinguals.

  12. Measurement of activity distribution using photostimulable phosphor imaging plates in decommissioned 10 MV medical linear accelerator.

    PubMed

    Fujibuchi, Toshioh; Yonai, Shunsuke; Yoshida, Masahiro; Sakae, Takeji; Watanabe, Hiroshi; Abe, Yoshihisa; Itami, Jun

    2014-08-01

    Photonuclear reactions generate neutrons in the head of the linear accelerator. Therefore, some parts of the linear accelerator can become activated. Such activated materials must be handled as radioactive waste. The authors attempted to investigate the distribution of induced radioactivity using photostimulable phosphor imaging plates. Autoradiographs were produced from some parts of the linear accelerator (the target, upper jaw, multileaf collimator and shielding). The levels of induced radioactivity were confirmed to be non-uniform within each part from the autoradiographs. The method was a simple and highly sensitive approach to evaluating the relative degree of activation of the linear accelerators, so that appropriate materials management procedures can be carried out.

  13. Dual-Modality Activity-Based Probes as Molecular Imaging Agents for Vascular Inflammation.

    PubMed

    Withana, Nimali P; Saito, Toshinobu; Ma, Xiaowei; Garland, Megan; Liu, Changhao; Kosuge, Hisanori; Amsallem, Myriam; Verdoes, Martijn; Ofori, Leslie O; Fischbein, Michael; Arakawa, Mamoru; Cheng, Zhen; McConnell, Michael V; Bogyo, Matthew

    2016-10-01

    Macrophages are cellular mediators of vascular inflammation and are involved in the formation of atherosclerotic plaques. These immune cells secrete proteases such as matrix metalloproteinases and cathepsins that contribute to disease formation and progression. Here, we demonstrate that activity-based probes (ABPs) targeting cysteine cathepsins can be used in murine models of atherosclerosis to noninvasively image activated macrophage populations using both optical and PET/CT methods. The probes can also be used to topically label human carotid plaques demonstrating similar specific labeling of activated macrophage populations.

  14. Reduction of computational complexity in the image/video understanding systems with active vision

    NASA Astrophysics Data System (ADS)

    Kuvich, Gary

    2003-10-01

    The vision system evolved not only as a recognition system, but also as a sensory system for reaching, grasping and other motion activities. In advanced creatures, it became a component of prediction function, allowing creation of environmental models and activity planning. Fast information processing and decision making is vital for any living creature, and requires reduction of informational and computational complexities. The brain achieves this goal using symbolic coding, hierarchical compression, and selective processing of visual information. Network-Symbolic representation, where both systematic structural / logical methods and neural / statistical methods are the parts of a single mechanism, is the most feasible for such models. It converts visual information into the relational Network-Symbolic structures, instead of precise computations of a 3-dimensional models. Narrow foveal vision provides separation of figure from ground, object identification, semantic analysis, and precise control of actions. Rough wide peripheral vision identifies and tracks salient motion, guiding foveal system to salient objects. It also provides scene context. Objects with rigid bodies and other stable systems have coherent relational structures. Hierarchical compression and Network-Symbolic transformations derive more abstract structures that allow invariably recognize a particular structure as an exemplar of class. Robotic systems equipped with such smart vision will be able effectively navigate in any environment, understand situation, and act accordingly.

  15. Representational pseudoneglect for detecting changes to Rey-Osterrieth figures.

    PubMed

    Aniulis, Ellie; Churches, Owen; Thomas, Nicole A; Nicholls, Michael E R

    2016-11-01

    When dividing attention between the left and right sides of physical space, most individuals pay slightly more attention to the left side. This phenomenon, known as pseudoneglect, may also occur for the left and right sides of mental representations of stimuli. Representational pseudoneglect has been shown for the recall of real-world scenes and for simple, briefly presented stimuli. The current study sought to investigate the effect of exposure duration and complexity using adaptations of the Rey-Osterrieth figures. Undergraduates (n = 97) were shown a stimulus for 20 s and asked to remember it. Participants were then shown a probe and indicated whether it was the same or different. Results showed that, irrespective of whether an element was added or subtracted, changes on the left side of the remembered image were better detected. These results are consistent with representational pseudoneglect and demonstrate that this effect occurs for complex stimuli when presented for an extended period of time. Representation neglect is therefore unlikely to be the result of an initial saccade to the left-but could be related to the formation or recall of the representation.

  16. Chronic imaging of movement-related Purkinje cell calcium activity in awake behaving mice

    PubMed Central

    Gaffield, Michael A.; Amat, Samantha B.; Bito, Haruhiko

    2015-01-01

    Purkinje cells (PCs) are a major site of information integration and plasticity in the cerebellum, a brain region involved in motor task refinement. Thus PCs provide an ideal location for studying the mechanisms necessary for cerebellum-dependent motor learning. Increasingly, sophisticated behavior tasks, used in combination with genetic reporters and effectors of activity, have opened up the possibility of studying cerebellar circuits during voluntary movement at an unprecedented level of quantitation. However, current methods used to monitor PC activity do not take full advantage of these advances. For example, single-unit or multiunit electrode recordings, which provide excellent temporal information regarding electrical activity, only monitor a small population of cells and can be quite invasive. Bolus loading of cell-permeant calcium (Ca2+) indicators is short-lived, requiring same-day imaging immediately after surgery and/or indicator injection. Genetically encoded Ca2+ indicators (GECIs) overcome many of these limits and have garnered considerable use in many neuron types but only limited use in PCs. Here we employed these indicators to monitor Ca2+ activity in PCs over several weeks. We could repeatedly image from the same cerebellar regions across multiple days and observed stable activity. We used chronic imaging to monitor PC activity in crus II, an area previously linked to licking behavior, and identified a region of increased activity at the onset of licking. We then monitored this same region after training tasks to initiate voluntary licking behavior in response to different sensory stimuli. In all cases, PC Ca2+ activity increased at the onset of rhythmic licking. PMID:26561609

  17. Real time in vivo imaging and measurement of serine protease activity in the mouse hippocampus using a dedicated complementary metal-oxide semiconductor imaging device.

    PubMed

    Ng, David C; Tamura, Hideki; Tokuda, Takashi; Yamamoto, Akio; Matsuo, Masamichi; Nunoshita, Masahiro; Ishikawa, Yasuyuki; Shiosaka, Sadao; Ohta, Jun

    2006-09-30

    The aim of the present study is to demonstrate the application of complementary metal-oxide semiconductor (CMOS) imaging technology for studying the mouse brain. By using a dedicated CMOS image sensor, we have successfully imaged and measured brain serine protease activity in vivo, in real-time, and for an extended period of time. We have developed a biofluorescence imaging device by packaging the CMOS image sensor which enabled on-chip imaging configuration. In this configuration, no optics are required whereby an excitation filter is applied onto the sensor to replace the filter cube block found in conventional fluorescence microscopes. The fully packaged device measures 350 microm thick x 2.7 mm wide, consists of an array of 176 x 144 pixels, and is small enough for measurement inside a single hemisphere of the mouse brain, while still providing sufficient imaging resolution. In the experiment, intraperitoneally injected kainic acid induced upregulation of serine protease activity in the brain. These events were captured in real time by imaging and measuring the fluorescence from a fluorogenic substrate that detected this activity. The entire device, which weighs less than 1% of the body weight of the mouse, holds promise for studying freely moving animals.

  18. Improving the diffuse optical imaging spatial resolution of the cerebral hemodynamic response to brain activation in humans

    NASA Astrophysics Data System (ADS)

    Boas, D. A.; Chen, K.; Grebert, D.; Franceschini, M. A.

    2004-07-01

    We compare two geometries of sources and detectors for optimizing the diffuse optical imaging resolution of brain activation in humans. Because of limitations in the instruments' dynamic range, most diffuse optical brain activation images have used only nonoverlapping measurements. We demonstrate theoretically and with a human experiment that a simple geometry of sources and detectors can provide overlapping measurements within the limitation of instrumentation dynamic range and produce an image resolution and localization accuracy that is twofold better.

  19. Functional photoacoustic imaging to observe regional brain activation induced by cocaine hydrochloride

    NASA Astrophysics Data System (ADS)

    Jo, Janggun; Yang, Xinmai

    2011-09-01

    Photoacoustic microscopy (PAM) was used to detect small animal brain activation in response to drug abuse. Cocaine hydrochloride in saline solution was injected into the blood stream of Sprague Dawley rats through tail veins. The rat brain functional change in response to the injection of drug was then monitored by the PAM technique. Images in the coronal view of the rat brain at the locations of 1.2 and 3.4 mm posterior to bregma were obtained. The resulted photoacoustic (PA) images showed the regional changes in the blood volume. Additionally, the regional changes in blood oxygenation were also presented. The results demonstrated that PA imaging is capable of monitoring regional hemodynamic changes induced by drug abuse.

  20. A Model for Diagnosing Breast Cancerous Tissue from Thermal Images Using Active Contour and Lyapunov Exponent

    PubMed Central

    GHAYOUMI ZADEH, Hossein; HADDADNIA, Javad; MONTAZERI, Alimohammad

    2016-01-01

    Background: The segmentation of cancerous areas in breast images is important for the early detection of disease. Thermal imaging has advantages, such as being non-invasive, non-radiation, passive, quick, painless, inexpensive, and non-contact. Imaging technique is the focus of this research. Methods: The proposed model in this paper is a combination of surf and corners that are very resistant. Obtained features are resistant to changes in rotation and revolution then with the help of active contours, this feature has been used for segmenting cancerous areas. Results: Comparing the obtained results from the proposed method and mammogram show that proposed method is Accurate and appropriate. Benign and malignance of segmented areas are detected by Lyapunov exponent. Values obtained include TP=91.31%, FN=8.69%, FP=7.26%. Conclusion: The proposed method can classify those abnormally segmented areas of the breast, to the Benign and malignant cancer. PMID:27398339