Sample records for visual search patterns

  1. Visual search patterns in neglect: Comparison of peripersonal and extrapersonal space

    Microsoft Academic Search

    Beverly C. Butler; Mike Lawrence; Gail A. Eskes; Raymond Klein

    2009-01-01

    Previous studies of visual search patterns in visuospatial neglect have analyzed shifts of attention during search tasks using eye tracking technology and verbal reports. The purpose of the present study was to replicate and extend upon reported parameters of visual scanning patterns of neglect patients in peripersonal space (within arms reach) and to examine whether similar patterns of visual search

  2. Visualized representation of visual search patterns for a visuospatial attention test

    Microsoft Academic Search

    Ho-Chuan Huang; Tsui-Ying Wang

    2008-01-01

    Cancellation tests have been widely used in clinical practice and in research to evaluate visuospatial attention, visual scanning\\u000a patterns, and neglect problems. The aim of the present work is to present a visualized interface for the visuospatial attentional\\u000a assessment system that can be employed to monitor and analyze attention performance and the search strategies used during\\u000a visuospatial processing of target

  3. Emotional Devaluation of Distracting Patterns and Faces: A Consequence of Attentional Inhibition During Visual Search?

    Microsoft Academic Search

    Jane E. Raymond; Mark J. Fenske; Nikki Westoby

    2005-01-01

    Visual search has been studied extensively, yet little is known about how its constituent processes affect subsequent emotional evaluation of searched-for and searched-through items. In 3 experiments, the authors asked observers to locate a colored pattern or tinted face in an array of other patterns or faces. Shortly thereafter, either the target or a distractor was rated on an emotional

  4. A Temporal Pattern Search Algorithm for Personal History Event Visualization

    E-print Network

    Shneiderman, Ben

    , sorted by time stamps. Instead, TPS operates on a set of arrays, where each array contains all events of the same type, sorted by time stamps. TPS searches for a particular item in the pattern using a binary a query for the purpose of exploratory analysis, the multiple turnarounds are detri- mental to the process

  5. Priming cases disturb visual search patterns in screening mammography

    NASA Astrophysics Data System (ADS)

    Lewis, Sarah J.; Reed, Warren M.; Tan, Alvin N. K.; Brennan, Patrick C.; Lee, Warwick; Mello-Thoms, Claudia

    2015-03-01

    Rationale and Objectives: To investigate the effect of inserting obvious cancers into a screening set of mammograms on the visual search of radiologists. Previous research presents conflicting evidence as to the impact of priming in scenarios where prevalence is naturally low, such as in screening mammography. Materials and Methods: An observer performance and eye position analysis study was performed. Four expert breast radiologists were asked to interpret two sets of 40 screening mammograms. The Control Set contained 36 normal and 4 malignant cases (located at case # 9, 14, 25 and 37). The Primed Set contained the same 34 normal and 4 malignant cases (in the same location) plus 2 "primer" malignant cases replacing 2 normal cases (located at positions #20 and 34). Primer cases were defined as lower difficulty cases containing salient malignant features inserted before cases of greater difficulty. Results: Wilcoxon Signed Rank Test indicated no significant differences in sensitivity or specificity between the two sets (P > 0.05). The fixation count in the malignant cases (#25, 37) in the Primed Set after viewing the primer cases (#20, 34) decreased significantly (Z = -2.330, P = 0.020). False-Negatives errors were mostly due to sampling in the Primed Set (75%) in contrast to in the Control Set (25%). Conclusion: The overall performance of radiologists is not affected by the inclusion of obvious cancer cases. However, changes in visual search behavior, as measured by eye-position recording, suggests visual disturbance by the inclusion of priming cases in screening mammography.

  6. An Experiment on the Effects of Program Code Highlighting on Visual Search for Local Patterns

    Microsoft Academic Search

    Tuomas Hakala; Pekka Nykyri; Jorma Sajaniemi

    2006-01-01

    Many current program editors use syntax highlighting but effects of various coloring schemes are not known. This paper presents the results of an experiment where three coloring schemes were used by intermediate programmers in visual search tasks for local patterns in Java programs. Differences between the coloring schemes were small and not statistically significant. Especially, in contrast to intuition, the

  7. Distractor ratio influences patterns of eye movements during visual search

    Microsoft Academic Search

    Jiye Shen; Eyal M Reingold; Marc Pomplun

    2000-01-01

    We examined the flexibility of guidance in a conjunctive search task by manipulating the ratios between different types of distractors. Participants were asked to decide whether a target was present or absent among distractors sharing either colour or shape. Results indicated a strong effect of distractor ratio on search performance. Shorter latency to move, faster manual response, and fewer fixations

  8. Linking physiology with behaviour: Functional specialisation of the visual field is reflected in gaze patterns during visual search

    Microsoft Academic Search

    Tobias Pflugshaupt; Roman von Wartburg; Pascal Wurtz; Silvia Chaves; Anouk Déruaz; Thomas Nyffeler; Sebastian von Arx; Mathias Luethi; Dario Cazzoli; René M. Mueri

    2009-01-01

    Based on neurophysiological findings and a grid to score binocular visual field function, two hypotheses concerning the spatial distribution of fixations during visual search were tested and confirmed in healthy participants and patients with homonymous visual field defects. Both groups showed significant biases of fixations and viewing time towards the centre of the screen and the upper screen half. Patients

  9. Eye movement trajectories in active visual search: Contributions of attention, memory, and scene boundaries to pattern formation

    Microsoft Academic Search

    T. D. Keech; L. Resca

    2010-01-01

    We relate the roles of attention, memory, and spatial constraints to pattern formation in eye movement trajectories previously\\u000a measured in a conjunctive visual search task. Autocorrelations and power spectra of saccade direction cosines confirm a bias\\u000a to progress forwardly, while turning at the display boundaries, plus a long-range memory component for the search path. Analyses\\u000a of certain measures of circulation

  10. Collaboration during visual search

    Microsoft Academic Search

    Kelly A. Malcolmson; Michael G. Reynolds; Daniel Smilek

    2007-01-01

    Two experiments examine how collaboration influences visual search performance. Working with a partner or on their own, participants\\u000a reported whether a target was present or absent in briefly presented search displays. We compared the search performance of\\u000a individuals working together (collaborative pairs) with the pooled responses of the individuals working alone (nominal pairs).\\u000a Collaborative pairs were less likely than nominal

  11. Feature Conjunctions in Visual Search

    Microsoft Academic Search

    Antonio Jose Rodríguez-sánchez; Evgueni Simine; John K. Tsotsos

    2006-01-01

    Selective Tuning (ST) [1] presents a framework for modeling attention and in this paper we show how it performs in visual\\u000a search tasks. Two types of tasks are presented, a motion search task and an object search task. Both tasks are successfully\\u000a tested with different feature and conjunction visual searches.

  12. Searching for camouflaged targets: Effects of target-background similarity on visual search

    E-print Network

    Zelinsky, Greg

    Searching for camouflaged targets: Effects of target-background similarity on visual search Mark B high TBS conditions. These data suggest a biased search process; salient patterns segmented from-based attention; Eye movements; Guided search 1. Introduction Visual search, our ability to detect a target among

  13. Visual Search Connecting Your World

    E-print Network

    Fisher, Kathleen

    's why AT&T Labs researchers have developed a mobile app that allows use of visuals or audio clips as search terms, instead of text. Visual Search is a powerful app that allows users to find products that you're curious about, you can simply take a photo of it ­ the app will search for it in its database

  14. Selective visual attention, visual search and visual awareness

    Microsoft Academic Search

    Charles M. Butter

    2004-01-01

    In a previous study, Butter and Goodale (2000) reported that visual search increases the identification of targets relative to distracters. The present series of studies investigated further this effect of search. Search increased identification of Ls when they were targets and decreased their identification when Ls were distracters in concurrent search involving feature conjunctions (Exp. 1). Subjects in Experiment 2

  15. The psychophysics of visual search

    Microsoft Academic Search

    John Palmer; Preeti Verghese; Misha Pavel

    2000-01-01

    Most theories of visual search emphasize issues of limited versus unlimited capacity and serial versus parallel processing. In the present article, we suggest a broader framework based on two principles, one empirical and one theoretical. The empirical principle is to focus on conditions at the intersection of visual search and the simple detection and discrimination paradigms of spatial vision. Such

  16. Hemispheric asymmetries in visual search

    Microsoft Academic Search

    William Poynter; Candice Roberts

    2011-01-01

    We conducted two visual search experiments, and found that target-detection accuracy and speed were better when the target was projected to the right hemisphere in the feature search condition and better when the target was projected to the left hemisphere in the feature-conjunction search condition. We propose that the highly efficient, so-called parallel search performance characteristic of feature search is

  17. Join patterns for visual basic

    Microsoft Academic Search

    Claudio V. Russo

    2008-01-01

    We describe an extension of Visual Basic 9.0 with asyn- chronous concurrency constructs - join patterns - based on the join calculus. Our design of Concurrent Basic (CB) builds on earlier work on Polyphonic C # and C!. Since that work, the need for language-integrated concurrency has only grown, both due to the arrival of commodity, multi-core hardware, and the

  18. Evolutionary pattern search algorithms

    SciTech Connect

    Hart, W.E.

    1995-09-19

    This paper defines a class of evolutionary algorithms called evolutionary pattern search algorithms (EPSAs) and analyzes their convergence properties. This class of algorithms is closely related to evolutionary programming, evolutionary strategie and real-coded genetic algorithms. EPSAs are self-adapting systems that modify the step size of the mutation operator in response to the success of previous optimization steps. The rule used to adapt the step size can be used to provide a stationary point convergence theory for EPSAs on any continuous function. This convergence theory is based on an extension of the convergence theory for generalized pattern search methods. An experimental analysis of the performance of EPSAs demonstrates that these algorithms can perform a level of global search that is comparable to that of canonical EAs. We also describe a stopping rule for EPSAs, which reliably terminated near stationary points in our experiments. This is the first stopping rule for any class of EAs that can terminate at a given distance from stationary points.

  19. ANTENNA DESIGN AND RADIATION PATTERN VISUALIZATION

    E-print Network

    Elsherbeni, Atef Z.

    ANTENNA DESIGN AND RADIATION PATTERN VISUALIZATION Atef Z. Elsherbeni, Matthew J. Inman, R and radiation patterns of many antenna geometries and antenna arrays can be evaluated but not easily visualized of the radiation patterns for many different types of antennas and antenna arrays. The package allows the user

  20. Development of a Computerized Visual Search Test

    ERIC Educational Resources Information Center

    Reid, Denise; Babani, Harsha; Jon, Eugenia

    2009-01-01

    Visual attention and visual search are the features of visual perception, essential for attending and scanning one's environment while engaging in daily occupations. This study describes the development of a novel web-based test of visual search. The development information including the format of the test will be described. The test was designed…

  1. Perceptual dependencies in information visualization assessed by complex visual search

    Microsoft Academic Search

    Ronald Van Den Berg; Frans W. Cornelissen; Jos B. T. M. Roerdink

    2008-01-01

    A common approach for visualizing data sets is to map them to images in which distinct data dimensions are mapped to distinct visual features, such as color, size and orientation. Here, we consider visualizations in which different data dimensions should receive equal weight and attention. Many of the end-user tasks performed on these images involve a form of visual search.

  2. Supporting Web Search with Visualization

    Microsoft Academic Search

    Orland Hoeber; Xue Dong Yang

    2010-01-01

    \\u000a One of the fundamental goals of Web-based support systems is to promote and support human activities on the Web. The focus\\u000a of this Chapter is on the specific activities associated with Web search, with special emphasis given to the use of visualization\\u000a to enhance the cognitive abilities of Web searchers. An overview of information retrieval basics, along with a focus

  3. Designing a Visual Interface for Online Searching.

    ERIC Educational Resources Information Center

    Lin, Xia

    1999-01-01

    "MedLine Search Assistant" is a new interface for MEDLINE searching that improves both search precision and recall by helping the user convert a free text search to a controlled vocabulary-based search in a visual environment. Features of the interface are described, followed by details of the conceptual design and the physical design of the…

  4. Statistical templates for visual search

    PubMed Central

    Ackermann, John F.; Landy, Michael S.

    2014-01-01

    How do we find a target embedded in a scene? Within the framework of signal detection theory, this task is carried out by comparing each region of the scene with a “template,” i.e., an internal representation of the search target. Here we ask what form this representation takes when the search target is a complex image with uncertain orientation. We examine three possible representations. The first is the matched filter. Such a representation cannot account for the ease with which humans can find a complex search target that is rotated relative to the template. A second representation attempts to deal with this by estimating the relative orientation of target and match and rotating the intensity-based template. No intensity-based template, however, can account for the ability to easily locate targets that are defined categorically and not in terms of a specific arrangement of pixels. Thus, we define a third template that represents the target in terms of image statistics rather than pixel intensities. Subjects performed a two-alternative, forced-choice search task in which they had to localize an image that matched a previously viewed target. Target images were texture patches. In one condition, match images were the same image as the target and distractors were a different image of the same textured material. In the second condition, the match image was of the same texture as the target (but different pixels) and the distractor was an image of a different texture. Match and distractor stimuli were randomly rotated relative to the target. We compared human performance to pixel-based, pixel-based with rotation, and statistic-based search models. The statistic-based search model was most successful at matching human performance. We conclude that humans use summary statistics to search for complex visual targets. PMID:24627458

  5. Beyond the Search Surface: Visual Search and Attentional Engagement

    Microsoft Academic Search

    John Duncan; Glyn Humphreys

    1992-01-01

    Treisman (1991) described a series of visual search studies testing feature integration theory against an alternative (Duncan & Humphreys, 1989) in which feature and conjunction search are basically similar. Here the latter account is noted to have 2 distinct levels: (a) a summary of search findings in terms of stimulus similarities, and (b) a theory of how visual attention is

  6. Words, shape, visual search and visual working memory in 3-year-old children

    PubMed Central

    Vales, Catarina; Smith, Linda B.

    2014-01-01

    Do words cue children’s visual attention, and if so, what are the relevant mechanisms? Across four experiments, 3-year-old children (N = 163) were tested in visual search tasks in which targets were cued with only a visual preview versus a visual preview and a spoken name. The experiments were designed to determine whether labels facilitated search times and to examine one route through which labels could have their effect: By influencing the visual working memory representation of the target. The targets and distractors were pictures of instances of basic-level known categories and the labels were the common name for the target category. We predicted that the label would enhance the visual working memory representation of the target object, guiding attention to objects that better matched the target representation. Experiments 1 and 2 used conjunctive search tasks, and Experiment 3 varied shape discriminability between targets and distractors. Experiment 4 compared the effects of labels to repeated presentations of the visual target, which should also influence the working memory representation of the target. The overall pattern fits contemporary theories of how the contents of visual working memory interact with visual search and attention, and shows that even in very young children heard words affect the processing of visual information. PMID:24720802

  7. Modeling the Visual Search of Displays

    E-print Network

    Byrne, Mike

    Modeling the Visual Search of Displays: A Revised ACT-R Model of Icon Search Based on Eye nearest to their current point of gaze. These findings were integrated into an ACT-R model of the task Search Literature Paradigm Preattentive Search Effects 1.2. ACT-R 5.0 ACT-R System Configuration

  8. Visual Search Across the Life Span

    Microsoft Academic Search

    Bernhard Hommel; Karen Z. H. Li; Shu-Chen Li

    2004-01-01

    Gains and losses in visual search were studied across the life span in a representative sample of 298 individuals from 6 to 89 years of age. Participants searched for single-feature and conjunction targets of high or low eccentricity. Search was substantially slowed early and late in life, age gradients were more pronounced in conjunction than in feature search, and all

  9. Temporal stability of visual search-driven biometrics

    NASA Astrophysics Data System (ADS)

    Yoon, Hong-Jun; Carmichael, Tandy R.; Tourassi, Georgia

    2015-03-01

    Previously, we have shown the potential of using an individual's visual search pattern as a possible biometric. That study focused on viewing images displaying dot-patterns with different spatial relationships to determine which pattern can be more effective in establishing the identity of an individual. In this follow-up study we investigated the temporal stability of this biometric. We performed an experiment with 16 individuals asked to search for a predetermined feature of a random-dot pattern as we tracked their eye movements. Each participant completed four testing sessions consisting of two dot patterns repeated twice. One dot pattern displayed concentric circles shifted to the left or right side of the screen overlaid with visual noise, and participants were asked which side the circles were centered on. The second dot-pattern displayed a number of circles (between 0 and 4) scattered on the screen overlaid with visual noise, and participants were asked how many circles they could identify. Each session contained 5 untracked tutorial questions and 50 tracked test questions (200 total tracked questions per participant). To create each participant's "fingerprint", we constructed a Hidden Markov Model (HMM) from the gaze data representing the underlying visual search and cognitive process. The accuracy of the derived HMM models was evaluated using cross-validation for various time-dependent train-test conditions. Subject identification accuracy ranged from 17.6% to 41.8% for all conditions, which is significantly higher than random guessing (1/16 = 6.25%). The results suggest that visual search pattern is a promising, temporally stable personalized fingerprint of perceptual organization.

  10. Universality in visual cortical pattern formation

    Microsoft Academic Search

    F. Wolf; T. Geisel

    2003-01-01

    During ontogenetic development, the visual cortical circuitry is remodeled by activity-dependent mechanisms of synaptic plasticity. From a dynamical systems perspective this is a process of dynamic pattern formation. The emerging cortical network supports functional activity patterns that are used to guide the further improvement of the network’s structure. In this picture, spontaneous symmetry breaking in the developmental dynamics of the

  11. Visual Search for Faces with Emotional Expressions

    ERIC Educational Resources Information Center

    Frischen, Alexandra; Eastwood, John D.; Smilek, Daniel

    2008-01-01

    The goal of this review is to critically examine contradictory findings in the study of visual search for emotionally expressive faces. Several key issues are addressed: Can emotional faces be processed preattentively and guide attention? What properties of these faces influence search efficiency? Is search moderated by the emotional state of the…

  12. Innate Visual Learning through Spontaneous Activity Patterns

    PubMed Central

    Albert, Mark V.; Schnabel, Adam; Field, David J.

    2008-01-01

    Patterns of spontaneous activity in the developing retina, LGN, and cortex are necessary for the proper development of visual cortex. With these patterns intact, the primary visual cortices of many newborn animals develop properties similar to those of the adult cortex but without the training benefit of visual experience. Previous models have demonstrated how V1 responses can be initialized through mechanisms specific to development and prior to visual experience, such as using axonal guidance cues or relying on simple, pairwise correlations on spontaneous activity with additional developmental constraints. We argue that these spontaneous patterns may be better understood as part of an “innate learning” strategy, which learns similarly on activity both before and during visual experience. With an abstraction of spontaneous activity models, we show how the visual system may be able to bootstrap an efficient code for its natural environment prior to external visual experience, and we continue the same refinement strategy upon natural experience. The patterns are generated through simple, local interactions and contain the same relevant statistical properties of retinal waves and hypothesized waves in the LGN and V1. An efficient encoding of these patterns resembles a sparse coding of natural images by producing neurons with localized, oriented, bandpass structure—the same code found in early visual cortical cells. We address the relevance of higher-order statistical properties of spontaneous activity, how this relates to a system that may adapt similarly on activity prior to and during natural experience, and how these concepts ultimately relate to an efficient coding of our natural world. PMID:18670593

  13. Fractal analysis of radiologists' visual scanning pattern in screening mammography

    NASA Astrophysics Data System (ADS)

    Alamudun, Folami T.; Yoon, Hong-Jun; Hudson, Kathy; Morin-Ducote, Garnetta; Tourassi, Georgia

    2015-03-01

    Several researchers have investigated radiologists' visual scanning patterns with respect to features such as total time examining a case, time to initially hit true lesions, number of hits, etc. The purpose of this study was to examine the complexity of the radiologists' visual scanning pattern when viewing 4-view mammographic cases, as they typically do in clinical practice. Gaze data were collected from 10 readers (3 breast imaging experts and 7 radiology residents) while reviewing 100 screening mammograms (24 normal, 26 benign, 50 malignant). The radiologists' scanpaths across the 4 mammographic views were mapped to a single 2-D image plane. Then, fractal analysis was applied on the composite 4- view scanpaths. For each case, the complexity of each radiologist's scanpath was measured using fractal dimension estimated with the box counting method. The association between the fractal dimension of the radiologists' visual scanpath, case pathology, case density, and radiologist experience was evaluated using fixed effects ANOVA. ANOVA showed that the complexity of the radiologists' visual search pattern in screening mammography is dependent on case specific attributes (breast parenchyma density and case pathology) as well as on reader attributes, namely experience level. Visual scanning patterns are significantly different for benign and malignant cases than for normal cases. There is also substantial inter-observer variability which cannot be explained only by experience level.

  14. Cascade category-aware visual search.

    PubMed

    Zhang, Shiliang; Tian, Qi; Huang, Qingming; Gao, Wen; Rui, Yong

    2014-06-01

    Incorporating image classification into image retrieval system brings many attractive advantages. For instance, the search space can be narrowed down by rejecting images in irrelevant categories of the query. The retrieved images can be more consistent in semantics by indexing and returning images in the relevant categories together. However, due to their different goals on recognition accuracy and retrieval scalability, it is hard to efficiently incorporate most image classification works into large-scale image search. To study this problem, we propose cascade category-aware visual search, which utilizes weak category clue to achieve better retrieval accuracy, efficiency, and memory consumption. To capture the category and visual clues of an image, we first learn category-visual words, which are discriminative and repeatable local features labeled with categories. By identifying category-visual words in database images, we are able to discard noisy local features and extract image visual and category clues, which are hence recorded in a hierarchical index structure. Our retrieval system narrows down the search space by: 1) filtering the noisy local features in query; 2) rejecting irrelevant categories in database; and 3) preforming discriminative visual search in relevant categories. The proposed algorithm is tested on object search, landmark search, and large-scale similar image search on the large-scale LSVRC10 data set. Although the category clue introduced is weak, our algorithm still shows substantial advantages in retrieval accuracy, efficiency, and memory consumption than the state-of-the-art. PMID:24760907

  15. Urban camouflage assessment through visual search and computational saliency

    NASA Astrophysics Data System (ADS)

    Toet, Alexander; Hogervorst, Maarten A.

    2013-04-01

    We present a new method to derive a multiscale urban camouflage pattern from a given set of background image samples. We applied this method to design a camouflage pattern for a given (semi-arid) urban environment. We performed a human visual search experiment and a computational evaluation study to assess the effectiveness of this multiscale camouflage pattern relative to the performance of 10 other (multiscale, disruptive and monotonous) patterns that were also designed for deployment in the same operating theater. The results show that the pattern combines the overall lowest detection probability with an average mean search time. We also show that a frequency-tuned saliency metric predicts human observer performance to an appreciable extent. This computational metric can therefore be incorporated in the design process to optimize the effectiveness of camouflage patterns derived from a set of background samples.

  16. Modeling spatial patterns in the visual cortex

    NASA Astrophysics Data System (ADS)

    Daza C., Yudy Carolina; Tauro, Carolina B.; Tamarit, Francisco A.; Gleiser, Pablo M.

    2014-10-01

    We propose a model for the formation of patterns in the visual cortex. The dynamical units of the model are Kuramoto phase oscillators that interact through a complex network structure embedded in two dimensions. In this way the strength of the interactions takes into account the geographical distance between units. We show that for different parameters, clustered or striped patterns emerge. Using the structure factor as an order parameter we are able to quantitatively characterize these patterns and present a phase diagram. Finally, we show that the model is able to reproduce patterns with cardinal preference, as observed in ferrets.

  17. Relax! Cognitive strategy influences visual search

    Microsoft Academic Search

    Daniel Smilek; James T. Enns; John D. Eastwood; Philip M. Merikle

    2006-01-01

    Two experiments evaluated whether visual search can be made more efficient by having participants give up active control over the guidance of attention. In Experiment 1 participants were instructed to search while either actively directing their attention to the target or by passively allowing the target to just “pop” into their minds. Results showed that passive instructions led to more

  18. The Search for Optimal Visual Stimuli

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B.; Ellis, Stephen R. (Technical Monitor)

    1997-01-01

    In 1983, Watson, Barlow and Robson published a brief report in which they explored the relative visibility of targets that varied in size, shape, spatial frequency, speed, and duration (referred to subsequently here as WBR). A novel aspect of that paper was that visibility was quantified in terms of threshold contrast energy, rather than contrast. As they noted, this provides a more direct measure of the efficiency with which various patterns are detected, and may be more edifying as to the underlying detection machinery. For example, under certain simple assumptions, the waveform of the most efficiently detected signal is an estimate of the receptive field of the visual system's most efficient detector. Thus one goal of their experiment Basuto search for the stimulus that the 'eye sees best'. Parenthetically, the search for optimal stimuli may be seen as the most general and sophisticated variant of the traditional 'subthreshold summation' experiment, in which one measures the effect upon visibility of small probes combined with a base stimulus.

  19. Visual abstraction of complex motion patterns

    NASA Astrophysics Data System (ADS)

    Janetzko, Halldór; Jäckle, Dominik; Deussen, Oliver; Keim, Daniel A.

    2013-12-01

    Today's tracking devices allow high spatial and temporal resolutions and due to their decreasing size also an ever increasing number of application scenarios. However, understanding motion over time is quite difficult as soon as the resulting trajectories are getting complex. Simply plotting the data may obscure important patterns since trajectories over long time periods often include many revisits of the same place which creates a high degree of over-plotting. Furthermore, important details are often hidden due to a combination of large-scale transitions with local and small-scale movement patterns. We present a visualization and abstraction technique for such complex motion data. By analyzing the motion patterns and displaying them with visual abstraction techniques a synergy of aggregation and simplification is reached. The capabilities of the method are shown in real-world applications for tracked animals and discussed with experts from biology. Our proposed abstraction techniques reduce visual clutter and help analysts to understand the movement patterns that are hidden in raw spatiotemporal data.

  20. Online Search Patterns: NLM CATLINE Database.

    ERIC Educational Resources Information Center

    Tolle, John E.; Hah, Sehchang

    1985-01-01

    Presents analysis of online search patterns within user searching sessions of National Library of Medicine ELHILL system and examines user search patterns on the CATLINE database. Data previously analyzed on MEDLINE database for same period is used to compare the performance parameters of different databases within the same information system.…

  1. Cardiac and Respiratory Responses During Visual Search in Nonretarded Children and Retarded Adolescents

    ERIC Educational Resources Information Center

    Porges, Stephen W.; Humphrey, Mary M.

    1977-01-01

    The relationship between physiological response patterns and mental competence was investigated by evaluating heart rate and respiratory responses during a sustained visual-search task in 29 nonretarded grade school children and 16 retarded adolescents. (Author)

  2. Do Multielement Visual Tracking and Visual Search Draw Continuously on the Same Visual Attention Resources?

    ERIC Educational Resources Information Center

    Alvarez, George A.; Horowitz, Todd S.; Arsenio, Helga C.; DiMase, Jennifer S.; Wolfe, Jeremy M.

    2005-01-01

    Multielement visual tracking and visual search are 2 tasks that are held to require visual-spatial attention. The authors used the attentional operating characteristic (AOC) method to determine whether both tasks draw continuously on the same attentional resource (i.e., whether the 2 tasks are mutually exclusive). The authors found that observers…

  3. Pattern Search Methods for Linearly Constrained Minimization

    NASA Technical Reports Server (NTRS)

    Lewis, Robert Michael; Torczon, Virginia

    1998-01-01

    We extend pattern search methods to linearly constrained minimization. We develop a general class of feasible point pattern search algorithms and prove global convergence to a Karush-Kuhn-Tucker point. As in the case of unconstrained minimization, pattern search methods for linearly constrained problems accomplish this without explicit recourse to the gradient or the directional derivative. Key to the analysis of the algorithms is the way in which the local search patterns conform to the geometry of the boundary of the feasible region.

  4. Target and nontarget grouping in visual search

    Microsoft Academic Search

    John Duncan

    1995-01-01

    Results recently reported by Driver, McLeod, and Dienes (1992) are used to contrast three accounts of visual search—in particular,\\u000a their mechanism for easy conjunction search. In the Driver et al. study, the target was defined by a conjunction of form and\\u000a movement; the key manipulation was phase in both target and nontarget motion sets. Mechanisms working separately on each display

  5. Involvement of prefrontal cortex in visual search

    Microsoft Academic Search

    E. J. Anderson; S. K. Mannan; M. Husain; G. Rees; P. Sumner; D. J. Mort; D. McRobbie; C. Kennard

    2007-01-01

    Visual search for target items embedded within a set of distracting items has consistently been shown to engage regions of\\u000a occipital and parietal cortex, but the contribution of different regions of prefrontal cortex remains unclear. Here, we used\\u000a fMRI to compare brain activity in 12 healthy participants performing efficient and inefficient search tasks in which target\\u000a discriminability and the number

  6. Visual search with imperfect recognition

    Microsoft Academic Search

    John Holmgren

    1968-01-01

    A task involving both the search for and recognition of one of two possible critical elements embedded in a set of noise elements\\u000a was investigated with the aid of a mathematical model. The model consists of three processes, these being search, recognition,\\u000a and decision. The first of two experiments attempted to show the operation of two separate bias parameters in

  7. The neurodynamics of visual search

    Microsoft Academic Search

    Gustavo Deco; Josef Zihl

    2006-01-01

    We review different functions in visual perception associated with attention and memory that have been integrated by a model based on the biased competition hypothesis. The model integrates, in a unifying form, the explanation of several existing types of experimental data obtained at different levels of investigation. At the microscopic level, single cell recordings are simulated. At the mesoscopic level

  8. ResultMaps: visualization for search interfaces.

    PubMed

    Clarkson, Edward; Desai, Krishna; Foley, James

    2009-01-01

    Hierarchical representations are common in digital repositories, yet are not always fully leveraged in their online search interfaces. This work describes ResultMaps, which use hierarchical treemap representations with query string-driven digital library search engines. We describe two lab experiments, which find that ResultsMap users yield significantly better results over a control condition on some subjective measures, and we find evidence that ResultMaps have ancillary benefits via increased understanding of some aspects of repository content. The ResultMap system and experiments contribute an understanding of the benefits--direct and indirect--of the ResultMap approach to repository search visualization. PMID:19834172

  9. Visual search for emotional faces in children

    Microsoft Academic Search

    Allison M. Waters; Ottmar V. Lipp

    2008-01-01

    The ability to rapidly detect facial expressions of anger and threat over other salient expressions has adaptive value across the lifespan. Although studies have demonstrated this threat superiority effect in adults, surprisingly little research has examined the development of this process over the childhood period. In this study, we examined the efficiency of children's facial processing in visual search tasks.

  10. Dynamic Prototypicality Effects in Visual Search

    ERIC Educational Resources Information Center

    Kayaert, Greet; Op de Beeck, Hans P.; Wagemans, Johan

    2011-01-01

    In recent studies, researchers have discovered a larger neural activation for stimuli that are more extreme exemplars of their stimulus class, compared with stimuli that are more prototypical. This has been shown for faces as well as for familiar and novel shape classes. We used a visual search task to look for a behavioral correlate of these…

  11. Background, an important factor in visual search.

    PubMed

    De Vries, Jelmer P; Hooge, Ignace T C; Wertheim, Alexander H; Verstraten, Frans A J

    2013-06-28

    The ability to detect an object depends on the contrast between the object and its background. Despite this, many models of visual search rely solely on the properties of target and distractors, and do not take the background into account. Yet, both target and distractors have their individual contrasts with the background. These contrasts generally differ, because the target and distractors are different in at least one feature. Therefore, background is likely to play an important role in visual search. In three experiments we manipulated the properties of the background (luminance, orientation and spatial frequency, respectively) while keeping the target and distractors constant. In the first experiment, in which target and distractors had a different luminance, changing the background luminance had an extensive effect on search times. When background luminance was in between that of the target and distractors, search times were always short. Interestingly, when the background was darker than both the target and the distractors, search times were much longer than when the background was lighter. Manipulating orientation and spatial frequency of the background, on the other hand, resulted in search times that were longest for small target-background differences. Thus, background plays an important role in search. This role depends on the individual contrast of both target and distractors with the background and the type of feature contrast (luminance, orientation or spatial frequency). PMID:23623804

  12. ON THE CONVERGENCE OF PATTERN SEARCH ALGORITHMS

    Microsoft Academic Search

    VIRGINIA TORCZON

    1997-01-01

    We introduce an abstract definition of pattern search methods for solving nonlinear unconstrained optimization problems. Our definition unifies an important collection of optimization methods that neither compute nor explicitly approximate derivatives. We exploit our characterization of pattern search methods to establish a global convergence theory that does not enforce a notion of sufficient decrease. Our analysis is possible because the

  13. Search Goal Tunes Visual Features Optimally Vidhya Navalpakkam1,

    E-print Network

    Itti, Laurent

    present a brief overview of the relevant visual search literature. The ``biased competition'' hypoth- esisNeuron Article Search Goal Tunes Visual Features Optimally Vidhya Navalpakkam1, * and Laurent Itti2.neuron.2007.01.018 SUMMARY How does a visual search goal modulate the activity of neurons encoding different

  14. Pattern electroretinogram, visual evoked potential and psychophysical functions in maculopathy

    Microsoft Academic Search

    Armin Junghardt; Hannes Wildberger; Béla Török

    1995-01-01

    To compare pattern electroretinograms and visual evoked potentials with psychophysical examinations, such as visual acuity, static (automated) perimetry and color vision in unilateral maculopathies of various origins, 20 patients with unilateral retinal diseases within the macula and the posterior pole were tested. Pattern electroretinography, visual evoked potential testing and static perimetry (Octopus program M1) were performed with three different test

  15. Vocal Dynamic Visual Pattern for voice characterization

    NASA Astrophysics Data System (ADS)

    Dajer, M. E.; Andrade, F. A. S.; Montagnoli, A. N.; Pereira, J. C.; Tsuji, D. H.

    2011-12-01

    Voice assessment requires simple and painless exams. Modern technologies provide the necessary resources for voice signal processing. Techniques based on nonlinear dynamics seem to asses the complexity of voice more accurately than other methods. Vocal dynamic visual pattern (VDVP) is based on nonlinear methods and provides qualitative and quantitative information. Here we characterize healthy and Reinke's edema voices by means of perturbation measures and VDVP analysis. VDPD and jitter show different results for both groups, while amplitude perturbation has no difference. We suggest that VDPD analysis improve and complement the evaluation methods available for clinicians.

  16. Pattern Visualization of Human Connectome Data

    PubMed Central

    Guo, Yishi; Wang, Yang; Fang, Shiaofen; Chao, Hongyang; Saykin, Andrew J.; Shen, Li

    2015-01-01

    The human brain is a complex network with countless connected neurons, and can be described as a “connectome”. Existing studies on analyzing human connectome data are primarily focused on characterizing the brain networks with a small number of easily computable measures that may be inadequate for revealing complex relationship between brain function and its structural substrate. To facilitate large-scale connectomic analysis, in this paper, we propose a powerful and flexible volume rendering scheme to effectively visualize and interactively explore thousands of network measures in the context of brain anatomy, and to aid pattern discovery. We demonstrate the effectiveness of the proposed scheme by applying it to a real connectome data set.

  17. An Information Theoretic Model of Saliency and Visual Search

    E-print Network

    observed visual search behavior and additionally is based on some basic well defined principle. It is ourAn Information Theoretic Model of Saliency and Visual Search Neil D.B. Bruce and John K. Tsotsos quantifies visual saliency based on an information theoretic definition is evaluated with respect to visual

  18. Visual Search and Dual Tasks Reveal Two Distinct Attentional Resources

    E-print Network

    Koch, Christof

    by visual attention. In visual search experiments, the detection of ``basic'' or ``preattentive'' featuresVisual Search and Dual Tasks Reveal Two Distinct Attentional Resources Rufin VanRullen1, *, Lavanya Reddy2, *, and Christof Koch2 Abstract & Most theories of visual processing assume that a target

  19. Similarity relations in visual search predict rapid visual categorization

    PubMed Central

    Mohan, Krithika; Arun, S. P.

    2012-01-01

    How do we perform rapid visual categorization?It is widely thought that categorization involves evaluating the similarity of an object to other category items, but the underlying features and similarity relations remain unknown. Here, we hypothesized that categorization performance is based on perceived similarity relations between items within and outside the category. To this end, we measured the categorization performance of human subjects on three diverse visual categories (animals, vehicles, and tools) and across three hierarchical levels (superordinate, basic, and subordinate levels among animals). For the same subjects, we measured their perceived pair-wise similarities between objects using a visual search task. Regardless of category and hierarchical level, we found that the time taken to categorize an object could be predicted using its similarity to members within and outside its category. We were able to account for several classic categorization phenomena, such as (a) the longer times required to reject category membership; (b) the longer times to categorize atypical objects; and (c) differences in performance across tasks and across hierarchical levels. These categorization times were also accounted for by a model that extracts coarse structure from an image. The striking agreement observed between categorization and visual search suggests that these two disparate tasks depend on a shared coarse object representation. PMID:23092947

  20. The Pattern of Learned Visual Improvements in Adult Amblyopia

    E-print Network

    Nottingham, University of

    be collapsed along two basic visual dimensions (visual acuity and contrast sensitivity) that together accountThe Pattern of Learned Visual Improvements in Adult Amblyopia Andrew T. Astle, Ben S. Webb for most of the variability in performance of the amblyopic visual system. In this study, this space

  1. Recognition of Facially Expressed Emotions and Visual Search Strategies in Adults with Asperger Syndrome

    ERIC Educational Resources Information Center

    Falkmer, Marita; Bjallmark, Anna; Larsson, Matilda; Falkmer, Torbjorn

    2011-01-01

    Can the disadvantages persons with Asperger syndrome frequently experience with reading facially expressed emotions be attributed to a different visual perception, affecting their scanning patterns? Visual search strategies, particularly regarding the importance of information from the eye area, and the ability to recognise facially expressed…

  2. Common Visual Pattern Discovery via Directed Graph.

    PubMed

    Wang, Chen; Ma, Kai-Kuang

    2014-03-01

    A directed graph (or digraph) approach is proposed in this paper for identifying all the visual objects commonly presented in the two images under comparison. As a model, the directed graph is superior to the undirected graph, since there are two link weights with opposite orientations associated with each link of the graph. However, it inevitably draws two main challenges: 1) how to compute the two link weights for each link and 2) how to extract the subgraph from the digraph. For 1), a novel n-ranking process for computing the generalized median and the Gaussian link-weight mapping function are developed that basically map the established undirected graph to the digraph. To achieve this graph mapping, the proposed process and function are applied to each vertex independently for computing its directed link weight by not only considering the influences inserted from its immediately adjacent neighboring vertices (in terms of their link-weight values), but also offering other desirable merits-i.e., link-weight enhancement and computational complexity reduction. For 2), an evolutionary iterative process for solving the non-cooperative game theory is exploited to handle the non-symmetric weighted adjacency matrix. The abovementioned two stages of processes will be conducted for each assumed scale-change factor, experimented over a range of possible values, one factor at a time. If there is a match on the scale-change factor under experiment, the common visual patterns with the same scale-change factor will be extracted. If more than one pattern are extracted, the proposed topological splitting method is able to further differentiate among them provided that the visual objects are sufficiently far apart from each other. Extensive simulation results have clearly demonstrated the superior performance accomplished by the proposed digraph approach, compared with those of using the undirected graph approach. PMID:24723536

  3. Investigation of Neural Strategies of Visual Search

    NASA Technical Reports Server (NTRS)

    Krauzlis, Richard J.

    2003-01-01

    The goal of this project was to measure how neurons in the superior colliculus (SC) change their activity during a visual search task. Specifically, we proposed to measure how the activity of these neurons was altered by the discriminability of visual targets and to test how these changes might predict the changes in the subjects performance. The primary rationale for this study was that understanding how the information encoded by these neurons constrains overall search performance would foster the development of better models of human performance. Work performed during the period supported by this grant has achieved these aims. First, we have recorded from neurons in the superior colliculus (SC) during a visual search task in which the difficulty of the task and the performance of the subject was systematically varied. The results from these single-neuron physiology experiments shows that prior to eye movement onset, the difference in activity across the ensemble of neurons reaches a fixed threshold value, reflecting the operation of a winner-take-all mechanism. Second, we have developed a model of eye movement decisions based on the principle of winner-take-all . The model incorporates the idea that the overt saccade choice reflects only one of the multiple saccades prepared during visual discrimination, consistent with our physiological data. The value of the model is that, unlike previous models, it is able to account for both the latency and the percent correct of saccade choices.

  4. Personalized online information search and visualization

    PubMed Central

    Chen, Dongquan; Orthner, Helmuth F; Sell, Susan M

    2005-01-01

    Background The rapid growth of online publications such as the Medline and other sources raises the questions how to get the relevant information efficiently. It is important, for a bench scientist, e.g., to monitor related publications constantly. It is also important, for a clinician, e.g., to access the patient records anywhere and anytime. Although time-consuming, this kind of searching procedure is usually similar and simple. Likely, it involves a search engine and a visualization interface. Different words or combination reflects different research topics. The objective of this study is to automate this tedious procedure by recording those words/terms in a database and online sources, and use the information for an automated search and retrieval. The retrieved information will be available anytime and anywhere through a secure web server. Results We developed such a database that stored searching terms, journals and et al., and implement a piece of software for searching the medical subject heading-indexed sources such as the Medline and other online sources automatically. The returned information were stored locally, as is, on a server and visible through a Web-based interface. The search was performed daily or otherwise scheduled and the users logon to the website anytime without typing any words. The system has potentials to retrieve similarly from non-medical subject heading-indexed literature or a privileged information source such as a clinical information system. The issues such as security, presentation and visualization of the retrieved information were thus addressed. One of the presentation issues such as wireless access was also experimented. A user survey showed that the personalized online searches saved time and increased and relevancy. Handheld devices could also be used to access the stored information but less satisfactory. Conclusion The Web-searching software or similar system has potential to be an efficient tool for both bench scientists and clinicians for their daily information needs. PMID:15766382

  5. Guidance of Eye Movements During Conjunctive Visual Search: The Distractor-Ratio Effect

    Microsoft Academic Search

    Jiye Shen; Eyal M. Reingold; Marc Pomplun

    2003-01-01

    The distractor-ratio effect refers to the finding that search performance in a conjunctive visual search task depends on the relative frequency of two types or subsets of distractors when the total number of items in a display is fixed. Previously, Shen, Reingold, and Pomplun (2000) examined participants' patterns of eye movements in a distractor-ratio paradigm and demonstrated that on any

  6. Competition-Induced Visual Field Differences in Search

    Microsoft Academic Search

    Jillian H. Fecteau; James T. Enns; Alan Kingstone

    2000-01-01

    Do visual field effects point to differences in cortical rep- resentation, or do they reflect differences in the way these represen- tations are used by other brain regions? This study explored three attributes of visual search that provide strong evidence in favor of differences in use. Competition refers to the finding that visual field differences in search efficiency are larger

  7. Large Visual Repository Search with Hash Collision Design Optimization

    E-print Network

    of this technology that enables large- scale visual search: indexing (or hashing). Index- ing is the process- ples of this new wave of applications enabled by large visual search capabilities. In these appli elements in our case are compact features extracted from images. In a typical indexing scheme for visual

  8. An active visual search interface for Medline.

    PubMed

    Xuan, Weijian; Dai, Manhong; Mirel, Barbara; Wilson, Justin; Athey, Brian; Watson, Stanley J; Meng, Fan

    2007-01-01

    Searching the Medline database is almost a daily necessity for many biomedical researchers. However, available Medline search solutions are mainly designed for the quick retrieval of a small set of most relevant documents. Because of this search model, they are not suitable for the large-scale exploration of literature and the underlying biomedical conceptual relationships, which are common tasks in the age of high throughput experimental data analysis and cross-discipline research. We try to develop a new Medline exploration approach by incorporating interactive visualization together with powerful grouping, summary, sorting and active external content retrieval functions. Our solution, PubViz, is based on the FLEX platform designed for interactive web applications and its prototype is publicly available at: http://brainarray.mbni.med.umich.edu/Brainarray/DataMining/PubViz. PMID:17951838

  9. Guided Text Search Using Adaptive Visual Analytics

    SciTech Connect

    Steed, Chad A [ORNL; Symons, Christopher T [ORNL; Senter, James K [ORNL; DeNap, Frank A [ORNL

    2012-10-01

    This research demonstrates the promise of augmenting interactive visualizations with semi- supervised machine learning techniques to improve the discovery of significant associations and insights in the search and analysis of textual information. More specifically, we have developed a system called Gryffin that hosts a unique collection of techniques that facilitate individualized investigative search pertaining to an ever-changing set of analytical questions over an indexed collection of open-source documents related to critical national infrastructure. The Gryffin client hosts dynamic displays of the search results via focus+context record listings, temporal timelines, term-frequency views, and multiple coordinate views. Furthermore, as the analyst interacts with the display, the interactions are recorded and used to label the search records. These labeled records are then used to drive semi-supervised machine learning algorithms that re-rank the unlabeled search records such that potentially relevant records are moved to the top of the record listing. Gryffin is described in the context of the daily tasks encountered at the US Department of Homeland Security s Fusion Center, with whom we are collaborating in its development. The resulting system is capable of addressing the analysts information overload that can be directly attributed to the deluge of information that must be addressed in the search and investigative analysis of textual information.

  10. Visual pattern discovery in timed event data

    NASA Astrophysics Data System (ADS)

    Schaefer, Matthias; Wanner, Franz; Mansmann, Florian; Scheible, Christian; Stennett, Verity; Hasselrot, Anders T.; Keim, Daniel A.

    2011-01-01

    Business processes have tremendously changed the way large companies conduct their business: The integration of information systems into the workflows of their employees ensures a high service level and thus high customer satisfaction. One core aspect of business process engineering are events that steer the workflows and trigger internal processes. Strict requirements on interval-scaled temporal patterns, which are common in time series, are thereby released through the ordinal character of such events. It is this additional degree of freedom that opens unexplored possibilities for visualizing event data. In this paper, we present a flexible and novel system to find significant events, event clusters and event patterns. Each event is represented as a small rectangle, which is colored according to categorical, ordinal or intervalscaled metadata. Depending on the analysis task, different layout functions are used to highlight either the ordinal character of the data or temporal correlations. The system has built-in features for ordering customers or event groups according to the similarity of their event sequences, temporal gap alignment and stacking of co-occurring events. Two characteristically different case studies dealing with business process events and news articles demonstrate the capabilities of our system to explore event data.

  11. Enhancing Network Trac Visualization by Graph Pattern Analysis

    Microsoft Academic Search

    Apeksha Godiyal; John C Hart

    Internet attacks are on the rise and pose serious security threats. Network trac visualization tools rely on human expertise to discover anomalies in trac and attack patterns. However, human ca- pacity to comprehend massive amounts of time-varying data is limited and the network visualization tools need further visual aid to extract interesting patters from such large and complex data sets.

  12. Explicit memory for rejected distractors during visual search

    Microsoft Academic Search

    Melissa R. Beck; Matthew S. Peterson; Walter R. Boot; Miroslava Vomela; Arthur F. Kramer

    2006-01-01

    Although memory for the identities of examined items is not used to guide visual search, identity memory may be acquired during visual search. In all experiments reported here, search was occasionally terminated and a memory test was presented for the identity of a previously examined item. Participants demonstrated memory for the locations of the examined items by avoiding revisits to

  13. Neural substrates for visual pattern recognition learning in Igo

    Microsoft Academic Search

    Kosuke Itoh; Hideaki Kitamura; Yukihiko Fujii; Tsutomu Nakada

    2008-01-01

    Different contexts require different visual pattern recognitions even for identical retinal inputs, and acquiring expertise in various visual-cognitive skills requires long-term training to become capable of recognizing relevant visual patterns in otherwise ambiguous stimuli. This 3-Tesla fMRI experiment exploited shikatsu-mondai (life-or-death problems) in the Oriental board game of Igo (Go) to identify the neural substrates supporting this gradual and adaptive

  14. Aging and Top-Down Attentional Control in Visual Search

    E-print Network

    McShea, Daniel W.

    Visual search and detection tasks are widely used to determine the cognitive components of visual object systems that bias the gating of this featural information to later processing stages such as object

  15. Reader error, object recognition, and visual search

    NASA Astrophysics Data System (ADS)

    Kundel, Harold L.

    2004-05-01

    Small abnormalities such as hairline fractures, lung nodules and breast tumors are missed by competent radiologists with sufficient frequency to make them a matter of concern to the medical community; not only because they lead to litigation but also because they delay patient care. It is very easy to attribute misses to incompetence or inattention. To do so may be placing an unjustified stigma on the radiologists involved and may allow other radiologists to continue a false optimism that it can never happen to them. This review presents some of the fundamentals of visual system function that are relevant to understanding the search for and the recognition of small targets embedded in complicated but meaningful backgrounds like chests and mammograms. It presents a model for visual search that postulates a pre-attentive global analysis of the retinal image followed by foveal checking fixations and eventually discovery scanning. The model will be used to differentiate errors of search, recognition and decision making. The implications for computer aided diagnosis and for functional workstation design are discussed.

  16. Orthographic versus semantic matching in visual search for words within lists.

    PubMed

    Léger, Laure; Rouet, Jean-François; Ros, Christine; Vibert, Nicolas

    2012-03-01

    An eye-tracking experiment was performed to assess the influence of orthographic and semantic distractor words on visual search for words within lists. The target word (e.g., "raven") was either shown to participants before the search (literal search) or defined by its semantic category (e.g., "bird", categorical search). In both cases, the type of words included in the list affected visual search times and eye movement patterns. In the literal condition, the presence of orthographic distractors sharing initial and final letters with the target word strongly increased search times. Indeed, the orthographic distractors attracted participants' gaze and were fixated for longer times than other words in the list. The presence of semantic distractors related to the target word also increased search times, which suggests that significant automatic semantic processing of nontarget words took place. In the categorical condition, semantic distractors were expected to have a greater impact on the search task. As expected, the presence in the list of semantic associates of the target word led to target selection errors. However, semantic distractors did not significantly increase search times any more, whereas orthographic distractors still did. Hence, the visual characteristics of nontarget words can be strong predictors of the efficiency of visual search even when the exact target word is unknown. The respective impacts of orthographic and semantic distractors depended more on the characteristics of lists than on the nature of the search task. PMID:22148903

  17. Words, Shape, Visual Search and Visual Working Memory in 3-Year-Old Children

    ERIC Educational Resources Information Center

    Vales, Catarina; Smith, Linda B.

    2015-01-01

    Do words cue children's visual attention, and if so, what are the relevant mechanisms? Across four experiments, 3-year-old children (N = 163) were tested in visual search tasks in which targets were cued with only a visual preview versus a visual preview and a spoken name. The experiments were designed to determine whether labels facilitated…

  18. Visual memory for natural scenes: Evidence from change detection and visual search

    Microsoft Academic Search

    Andrew Hollingworth

    2006-01-01

    This paper reviews research examining the role of visual memory in scene perception and visual search. Recent theories in these literatures have held that coherent object representations in visual memory are fleeting, disintegrating upon the withdrawal of attention from an object. I discuss evidence demonstrating that, far from being transient, visual memory supports the accumulation of information from scores of

  19. Attentional weighting: A possible account of visual field asymmetries in visual search?

    Microsoft Academic Search

    Amy A. Rezec; Karen R. Dobkins

    2004-01-01

    Abstract—Several previous,visual search studies measuring reaction times have,demonstrated scanning,biases across the visual field (i.e. a tendency,to begin a serial search in a particular region of space). In the present study, we measured visual discrimination thresholds for a target presented amongst,distractors using displays that were short enough,to greatly reduce the potential for serial (i.e. scanning) search. For both a motion and

  20. Visual search and eye movements in novel and familiar contexts

    NASA Astrophysics Data System (ADS)

    McDermott, Kyle; Mulligan, Jeffrey B.; Bebis, George; Webster, Michael A.

    2006-02-01

    Adapting to the visual characteristics of a specific environment may facilitate detecting novel stimuli within that environment. We monitored eye movements while subjects searched for a color target on familiar or unfamiliar color backgrounds, in order to test for these performance changes and to explore whether they reflect changes in salience from adaptation vs. changes in search strategies or perceptual learning. The target was an ellipse of variable color presented at a random location on a dense background of ellipses. In one condition, the colors of the background varied along either the LvsM or SvsLM cardinal axes. Observers adapted by viewing a rapid succession of backgrounds drawn from one color axis, and then searched for a target on a background from the same or different color axis. Searches were monitored with a Cambridge Research Systems Video Eyetracker. Targets were located more quickly on the background axis that observers were pre-exposed to, confirming that this exposure can improve search efficiency for stimuli that differ from the background. However, eye movement patterns (e.g. fixation durations and saccade magnitudes) did not clearly differ across the two backgrounds, suggesting that how the novel and familiar backgrounds were sampled remained similar. In a second condition, we compared search on a nonselective color background drawn from a circle of hues at fixed contrast. Prior exposure to this background did not facilitate search compared to an achromatic adapting field, suggesting that subjects were not simply learning the specific colors defining the background distributions. Instead, results for both conditions are consistent with a selective adaptation effect that enhances the salience of novel stimuli by partially discounting the background.

  1. Predicting Cognitive Strategies and Eye Movements in Hierarchical Visual Search

    E-print Network

    Hornof, Anthony

    Predicting Cognitive Strategies and Eye Movements in Hierarchical Visual Search Anthony J. Hornof to make a priori predictions of newly collected eye movement data. Based on what is learned here cognitive modeling of visual search, and the synergistic relationship between cognitive modeling and eye

  2. Spatial Constraints on Learning in Visual Search: Modeling Contextual Cuing

    Microsoft Academic Search

    Timothy F. Brady; Marvin M. Chun

    2007-01-01

    Predictive visual context facilitates visual search, a benefit termed contextual cuing (M. M. Chun & Y. Jiang, 1998). In the original task, search arrays were repeated across blocks such that the spatial configuration (context) of all of the distractors in a display predicted an embedded target location. The authors modeled existing results using a connectionist architecture and then designed new

  3. Global Statistical Learning in a Visual Search Task

    Microsoft Academic Search

    John L. Jones; Michael P. Kaschak

    2012-01-01

    Locating a target in a visual search task is facilitated when the target location is repeated on successive trials. Global statistical properties also influence visual search, but have often been confounded with local regularities (i.e., target location repetition). In two experiments, target locations were not repeated for four successive trials, but with a target location bias (i.e., the target appeared

  4. Visual similarity is stronger than semantic similarity in guiding visual search for numbers.

    PubMed

    Godwin, Hayward J; Hout, Michael C; Menneer, Tamaryn

    2014-06-01

    Using a visual search task, we explored how behavior is influenced by both visual and semantic information. We recorded participants' eye movements as they searched for a single target number in a search array of single-digit numbers (0-9). We examined the probability of fixating the various distractors as a function of two key dimensions: the visual similarity between the target and each distractor, and the semantic similarity (i.e., the numerical distance) between the target and each distractor. Visual similarity estimates were obtained using multidimensional scaling based on the independent observer similarity ratings. A linear mixed-effects model demonstrated that both visual and semantic similarity influenced the probability that distractors would be fixated. However, the visual similarity effect was substantially larger than the semantic similarity effect. We close by discussing the potential value of using this novel methodological approach and the implications for both simple and complex visual search displays. PMID:24347113

  5. Visualizing flow patterns in coupled geomechanical simulation using streamlines

    E-print Network

    Parihar, Prannay

    2009-05-15

    dynamics through visualization of flow patterns in the reservoir. Streamline tracing is a proved reservoir engineering tool that is widely used by industry experts to capture information on flood movement, injector-producer relations and swept area...

  6. Searching through subsets: A test of the Visual Indexing Hypothesis

    E-print Network

    Pylyshyn, Zenon

    support the basic claim of the indexing theory: The claim that multiple visual indexes are usedSearching through subsets: A test of the Visual Indexing Hypothesis Burkell, Jacquelyn A experiments investigating the claim that the visual system utilizes a primitive indexing mechanism (sometimes

  7. Lifespan changes in attention: The visual search task

    Microsoft Academic Search

    Lana M. Trick; James T. Enns

    1998-01-01

    There are two popular frameworks for the study of visual attention. Treisman's Feature Integration Theory focuses on the effortful process of binding together the multiple attributes of an object. Posner's Visual Orienting Theory emphasizes the movement of an attentional spotlight across space. Although both aspects are undoubtedly important in any visual search task, it is not clear how each of

  8. Visual Search Deficits Are Independent of Magnocellular Deficits in Dyslexia

    ERIC Educational Resources Information Center

    Wright, Craig M.; Conlon, Elizabeth G.; Dyck, Murray

    2012-01-01

    The aim of this study was to investigate the theory that visual magnocellular deficits seen in groups with dyslexia are linked to reading via the mechanisms of visual attention. Visual attention was measured with a serial search task and magnocellular function with a coherent motion task. A large group of children with dyslexia (n = 70) had slower…

  9. How important is lateral masking in visual search?

    Microsoft Academic Search

    A. H. Wertheim; I. T. C. Hooge; K. Krikke; A. Johnson

    2006-01-01

    Five experiments are presented, providing empirical support of the hypothesis that the sensory phenomenon of lateral masking\\u000a may explain many well-known visual search phenomena that are commonly assumed to be governed by cognitive attentional mechanisms.\\u000a Experiment I showed that when the same visual arrays are used in visual search and in lateral masking experiments, the factors\\u000a (1) number of distractors,

  10. Visual Search Behavior while Viewing Driving Scenes under the Influence of Alcohol and Marihuana

    Microsoft Academic Search

    Herbert Moskowitz; Kenneth Ziedman; Satanand Sharma

    1976-01-01

    Two experiments were performed to determine the effects of alcohol and marihuana on visual scanning patterns in a simulated driving situation. In the first experiment 27 male heavy drinkers were divided into three groups of nine, defined by three blood alcohol levels produced by alcohol treatment: 0.0%, 0.075%, and 0.15% BAC's. Significant changes in visual search behavior including increased dwell

  11. Usage Patterns of an Online Search System.

    ERIC Educational Resources Information Center

    Cooper, Michael D.

    1983-01-01

    Examines usage patterns of ELHILL retrieval program of National Library of Medicine's MEDLARS system. Based on sample of 6,759 searches, the study analyzes frequency of various commands, classifies messages issued by system, and investigates searcher error rates. Suggestions for redesigning program and query language are noted. Seven references…

  12. INTRODUCTION Human visual search is an important aspect of

    E-print Network

    Duchowski, Andrew T.

    © 2006, Human Factors and Ergonomics Society. All rights reserved #12;SEMISYSTEMATIC SEARCH MODEL 541INTRODUCTION Human visual search is an important aspect of many civilian and military applications replaced the human eye as the primary search instrument, the information is fre- quently still transferred

  13. Probing distractor inhibition in visual search: Inhibition of return

    Microsoft Academic Search

    Hermann J. Müller; Adrian von Miihlenen

    2000-01-01

    The mle of inhibition of retum (IOR) in serial visual search was reinvestigated using R. Klein's (1988) paradigm of a seatvh task followed by a probe-detection task. Robes were presented at either the location of a potentially inhibited mh distractor or an empty location. No evidence of IOR was obtained when the search objects were removed after the search-task response.

  14. Applying models of visual search to menu design

    Microsoft Academic Search

    Baili Liu; Gregory Francis; Gavriel Salvendy

    2002-01-01

    The Guided Search (GS) model, a quantitative model of visual search, was used to develop menu designs in a four-step process. First, a GS simulation model was defined for a menu search task. Second, model parameters were estimated to provide the best fit between model predictions and experimental data. Third, an optimization algorithm was used to identify the menu design

  15. Visual search in a forced-choice paradigm

    NASA Technical Reports Server (NTRS)

    Holmgren, J. E.

    1974-01-01

    The processing of visual information was investigated in the context of two visual search tasks. The first was a forced-choice task in which one of two alternative letters appeared in a visual display of from one to five letters. The second task included trials on which neither of the two alternatives was present in the display. Search rates were estimated from the slopes of best linear fits to response latencies plotted as a function of the number of items in the visual display. These rates were found to be much slower than those estimated in yes-no search tasks. This result was interpreted as indicating that the processes underlying visual search in yes-no and forced-choice tasks are not the same.

  16. Reinforcing saccadic amplitude variability in a visual search task.

    PubMed

    Paeye, Céline; Madelain, Laurent

    2014-01-01

    Human observers often adopt rigid scanning strategies in visual search tasks, even though this may lead to suboptimal performance. Here we ask whether specific levels of saccadic amplitude variability may be induced in a visual search task using reinforcement learning. We designed a new gaze-contingent visual foraging task in which finding a target among distractors was made contingent upon specific saccadic amplitudes. When saccades of rare amplitudes led to displaying the target, the U values (measuring uncertainty) increased by 54.89% on average. They decreased by 41.21% when reinforcing frequent amplitudes. In a noncontingent control group no consistent change in variability occurred. A second experiment revealed that this learning transferred to conventional visual search trials. These results provide experimental support for the importance of reinforcement learning for saccadic amplitude variability in visual search. PMID:25413626

  17. Searching for intellectual turning points: Progressive knowledge domain visualization

    PubMed Central

    Chen, Chaomei

    2004-01-01

    This article introduces a previously undescribed method progressively visualizing the evolution of a knowledge domain's cocitation network. The method first derives a sequence of cocitation networks from a series of equal-length time interval slices. These time-registered networks are merged and visualized in a panoramic view in such a way that intellectually significant articles can be identified based on their visually salient features. The method is applied to a cocitation study of the superstring field in theoretical physics. The study focuses on the search of articles that triggered two superstring revolutions. Visually salient nodes in the panoramic view are identified, and the nature of their intellectual contributions is validated by leading scientists in the field. The analysis has demonstrated that a search for intellectual turning points can be narrowed down to visually salient nodes in the visualized network. The method provides a promising way to simplify otherwise cognitively demanding tasks to a search for landmarks, pivots, and hubs. PMID:14724295

  18. Visualizing Predictability of File Access Patterns

    Microsoft Academic Search

    Alison Luo; Ahmed Amer; Newton Der; Darrell D. E. Long; Alex Pang

    We propose a novel method to study storage system pre- dictability based on the visualization of file successor en- tropy, a form of conditional entropy drawn from a file ac- cess trace. First-order conditional entropy is used as a measure of predictability. It is superior to the more com- mon measures such as independent likelihood of data ac- cess. For

  19. Efficient hybrid search for visual reconstruction problems

    Microsoft Academic Search

    Shang-Hong Lai; Baba C. Vemuri

    Visual reconstruction refers to extracting stable descriptions from visual data ((1); A. Blake and A. Zisserman, Visual Reconstruction, MIT Press, Cambridge, MA, 1987). Visual reconstruction problems are commonly formulated in an optimization framework and normally require the optimization of nonconvex functions especially when discontinuity preserving image\\/shape recovery is the goal. Example problems include, image restoration, surface reconstruction, shape from shading

  20. The Pattern of Learned Visual Improvements in Adult Amblyopia

    PubMed Central

    Webb, Ben S.; McGraw, Paul V.

    2011-01-01

    Purpose. Although amblyopia is diagnosed in terms of a monocular letter acuity loss, individuals typically present with deficits on a wide range of spatial tasks. Many of these deficits can be collapsed along two basic visual dimensions (visual acuity and contrast sensitivity) that together account for most of the variability in performance of the amblyopic visual system. In this study, this space was exploited, to target the main deficits and fully characterize the pattern of learned visual improvements in adult amblyopic subjects. Methods. Twenty-six amblyopic subjects (mean age, 39 ±12 years) were trained on one of four tasks, categorized as either visual acuity (letter or grating acuity) or contrast sensitivity (letter or grating contrast) tasks. Performance was measured on all tasks before and after training, to quantify learning along each dimension and generalization to the other dimension. Performance in 35 visually normal subjects (mean, age 24 ± 5 years) was used to establish normal variation in visual performance along each dimension, against which the learned improvements in amblyopic subjects was compared. Results. Training on the contrast sensitivity tasks produced substantial within-task learning and generalization to measures of visual acuity. The learned improvements in performance after training on the letter acuity task were also substantial, but did not generalize to contrast sensitivity. Conclusions. Mapping the pattern of learning onto the known deficit space for amblyopia enabled the identification of tasks and stimulus configurations that optimized learning, guiding further development of learning-based interventions in this clinical group. PMID:21810976

  1. The effect of face inversion on the detection of emotional faces in visual search.

    PubMed

    Savage, Ruth A; Lipp, Ottmar V

    2015-09-01

    Past literature has indicated that face inversion either attenuates emotion detection advantages in visual search, implying that detection of emotional expressions requires holistic face processing, or has no effect, implying that expression detection is feature based. Across six experiments that utilised different task designs, ranging from simple (single poser, single set size) to complex (multiple posers, multiple set sizes), and stimuli drawn from different databases, significant emotion detection advantages were found for both upright and inverted faces. Consistent with past research, the nature of the expression detection advantage, anger superiority (Experiments 1, 2 and 6) or happiness superiority (Experiments 3, 4 and 5), differed across stimulus sets. However both patterns were evident for upright and inverted faces. These results indicate that face inversion does not interfere with visual search for emotional expressions, and suggest that expression detection in visual search may rely on feature-based mechanisms. PMID:25229360

  2. Visualizing Digital Library Search Results with Categorical and Hierarchical Axes

    E-print Network

    Golbeck, Jennifer

    Visualizing Digital Library Search Results with Categorical and Hierarchical Axes Ben Shneiderman a simplified two­dimensional display that uses categorical and hierarchical axes, called hieraxes. Users, categorical axes, hieraxes INTRODUCTION Digital library researchers face numerous challenges in helping users

  3. Visualizing Digital Library Search Results with Categorical and Hierarchical Axes

    E-print Network

    Shneiderman, Ben

    57 Visualizing Digital Library Search Results with Categorical and Hierarchical Axes Ben a simplified two-dimensional display that uses categorical and hierarchical axes, called hieraxes. Users, categorical axes, hieraxes INTRODUCTION Digital library researchers face numerous challenges in helping users

  4. Searching Efficiency on Complex Networks Under Visual Range of Nodes

    NASA Astrophysics Data System (ADS)

    Liu, Bin; Deng, Hongzhong; Wu, Xiaoyue

    We study the searching efficiency of complex networks considering node's visual range within which a node can see its neighbors and knows the topology. We firstly introduce the network generating models and searching strategies. Using the generating function method, in both random networks and scale-free networks we derive the most-effective-visual-range (MEVR) which means every step of random walkers can find most of new nodes and we also obtain the searching-cost (SC) under visual range. To validate the generating function method, we perform simulations in random networks and scale-free networks. We also explain why the deviation between numerical simulation and theoretical prediction in scale-free networks is much larger than that in random networks. By studying the visual range of nodes in the networks, the results open the possibility to learn about the searching on networks with unknown topologies.

  5. A Term Distribution Visualization Approach to Digital Forensic String Search

    Microsoft Academic Search

    Moses Schwartz; Lorie M. Liebrock

    2008-01-01

    Digital forensic string search is vital to the forensic discovery process, but there has been little research on improving\\u000a tools or methods for this task. We propose the use of term distribution visualizations to aid digital forensic string search\\u000a tasks. Our visualization model enables an analyst to quickly identify relevant sections of a text and provides brushing and\\u000a drilling-down capabilities

  6. A Common Discrete Resource for Visual Working Memory and Visual Search

    PubMed Central

    Anderson, David E.; Vogel, Edward K.; Awh, Edward

    2014-01-01

    Visual search, a dominant paradigm within attention research, requires observers to rapidly identify targets hidden among distractors. Major models of search presume that working memory (WM) provides the on-line work space for evaluating potential targets. According to this hypothesis, individuals with higher WM capacity should search more efficiently, because they should be able to apprehend a larger number of search elements at a time. Nevertheless, no compelling evidence of such a correlation has emerged, and this null result challenges a growing consensus that there is strong overlap between the neural processes that limit internal storage and those that limit external selection. Here, we provide multiple demonstrations of robust correlations between WM capacity and search efficiency, and we document a key boundary condition for observing this link. Finally, examination of a neural measure of visual selection capacity (the N2pc) demonstrates that visual search and WM storage are constrained by a common discrete resource. PMID:23572280

  7. Visual Search by Children with and without ADHD

    ERIC Educational Resources Information Center

    Mullane, Jennifer C.; Klein, Raymond M.

    2008-01-01

    Objective: To summarize the literature that has employed visual search tasks to assess automatic and effortful selective visual attention in children with and without ADHD. Method: Seven studies with a combined sample of 180 children with ADHD (M age = 10.9) and 193 normally developing children (M age = 10.8) are located. Results: Using a…

  8. Varieties of Attention: A Model of Visual Search

    Microsoft Academic Search

    Giedrius T. Burdas; Thomas D. Albright; Terrence J. Sejnowski

    1996-01-01

    We have trained monkeys to perform a feature conjunction search task for color and motion and have recorded from neurons in area MT during the performance of this task. In order to put the experimental results into a theoretical context, we have developed a system-level model of visual processing incorporating several attentional mechanisms known to function in mammalian visual systems.

  9. Prism adaptation improves visual search in hemispatial neglect

    Microsoft Academic Search

    Styrmir Saevarsson; Árni Kristjánsson; Helmut Hildebrandt; Ulrike Halsband

    2009-01-01

    Visuomotor prism adaptation has been found to induce a lateral bias of spatial attention in chronic hemispatial neglect patients. Here, two experiments were conducted to explore the effects of 10° prism adaptation on visual search tasks and standard visual inattention tests. Baselines and intervention effects were measured on separate days for all patients. The first experiment explored whether prism adaptation

  10. Unintended Effects: Varying Icon Spacing Changes Users' Visual Search Strategy

    E-print Network

    Byrne, Mike

    and associated selection errors. Further research could help reduce this cost as better-designed icons couldUnintended Effects: Varying Icon Spacing Changes Users' Visual Search Strategy Sarah P. Everett control items, such as buttons and icons. Because this is so ubiquitous, it is important that the visual

  11. Visual search, anticipation and expertise in soccer goalkeepers

    Microsoft Academic Search

    Geert J. P. Savelsbergh; A. Mark Williams; John Van Der Kamp; Paul Ward

    2002-01-01

    We used a novel methodological approach to examine skill-based differences in anticipation and visual search behaviour during the penalty kick in soccer. Expert and novice goalkeepers were required to move a joystick in response to penalty kicks presented on film. The proportion of penalties saved was assessed, as well as the frequency and time of initiation of joystick corrections. Visual

  12. Visual Search in a Multi-Element Asynchronous Dynamic (MAD) World

    ERIC Educational Resources Information Center

    Kunar, Melina A.; Watson, Derrick G.

    2011-01-01

    In visual search tasks participants search for a target among distractors in strictly controlled displays. We show that visual search principles observed in these tasks do not necessarily apply in more ecologically valid search conditions, using dynamic and complex displays. A multi-element asynchronous dynamic (MAD) visual search was developed in…

  13. A Bayesian model for efficient visual search and recognition Lior Elazary a,*, Laurent Itti b

    E-print Network

    Itti, Laurent

    for a particular ob- ject. For example, if we wish to search for a green bottle, we could bias the visual system soA Bayesian model for efficient visual search and recognition Lior Elazary a,*, Laurent Itti b searching for our car). Previous re- search has shown that visual search tasks can be performed faster when

  14. Spacing affects some but not all visual searches: Implications for theories of attention and crowding

    E-print Network

    VanRullen, Rufin

    : visual search, serial search, crowding, spacing effects, attention, biased competition, featureSpacing affects some but not all visual searches: Implications for theories of attention of crowding. The observed spacing effect in visual search suggests that for certain tasks, serial search may

  15. How important is lateral masking in visual search?

    PubMed

    Wertheim, A H; Hooge, I T C; Krikke, K; Johnson, A

    2006-04-01

    Five experiments are presented, providing empirical support of the hypothesis that the sensory phenomenon of lateral masking may explain many well-known visual search phenomena that are commonly assumed to be governed by cognitive attentional mechanisms. Experiment I showed that when the same visual arrays are used in visual search and in lateral masking experiments, the factors (1) number of distractors, (2) distractor density, and (3) search type (conjunction vs disjunction) have the same effect on search times as they have on lateral masking scores. Experiment II showed that when the number of distractors and eccentricity is kept constant in a search task, the effect of reducing density (which reduces the lateral masking potential of distractors on the target) is to strongly reduce the disjunction-conjunction difference. In experiment III, the lateral masking potential of distractors on a target was measured with arrays that typically yield asymmetric search times in visual search studies (a Q among Os vs. an O among Qs). The lateral masking scores showed the same asymmetry. Experiment IV was a visual search study with such asymmetric search arrays in which the number of distractors and eccentricity was kept constant, while manipulating density. Reducing density (i.e., reducing lateral masking) produced a strong reduction of the asymmetry effect. Finally in experiment V, we showed that the data from experiment IV cannot be explained due to a difference between a fine and a coarse grain attentional mechanism. Taken together with eye movement data and error scores from experiment II and with similar findings from the literature, these results suggest that the sensory mechanism of lateral masking could well be a very important (if not the main) factor causing many of the well-known effects that are traditionally attributed to higher level cognitive or attentional mechanisms in visual search. PMID:16328267

  16. The individual and relative contributions of different regions of the visual field to visual search 

    E-print Network

    Greenwood Mears, Ruth

    2012-06-27

    The individual and relative contributions of foveal, central and peripheral vision to object-scene search were assessed using the window and scotoma paradigms. The visual field simulation (window or scotoma and a control), ...

  17. Spatial context and top-down strategies in visual search

    Microsoft Academic Search

    Alejandro Lleras; Adrian Von Mühlenen

    2004-01-01

    Abstract—Marvin M. Chun and Yuhong Jiang (1998) investigated the role of spatial context on visual search. They used two display conditions. In the Old Display condition, the spatial arrangement of items in the search display was kept constant throughout the experiment. In the New Display condition, the spatial arrangement of items was always novel from trial to trial. The results

  18. Why Is Visual Search Superior in Autism Spectrum Disorder?

    ERIC Educational Resources Information Center

    Joseph, Robert M.; Keehn, Brandon; Connolly, Christine; Wolfe, Jeremy M.; Horowitz, Todd S.

    2009-01-01

    This study investigated the possibility that enhanced memory for rejected distractor locations underlies the superior visual search skills exhibited by individuals with autism spectrum disorder (ASD). We compared the performance of 21 children with ASD and 21 age- and IQ-matched typically developing (TD) children in a standard static search task…

  19. Hiding and finding: The relationship between visual concealment and visual search

    Microsoft Academic Search

    Daniel Smilek; Laura Weinheimer; Donna Kwan; Mike Reynolds; Alan Kingstone

    2009-01-01

    As an initial step toward developing a theory of visual concealment, we assessed whether people would use factors known to\\u000a influence visual search difficulty when the degree of concealment of objects among distractors was varied. In Experiment 1,\\u000a participants arranged search objects (shapes, emotional faces, and graphemes) to create displays in which the targets were\\u000a in plain sight but were

  20. The role of visual working memory (VWM) in the control of gaze during visual search

    Microsoft Academic Search

    Andrew Hollingworth; Steven J. Luck

    2009-01-01

    We investigated the interactions among visual working memory (VWM), attention, and gaze control in a visual search task that\\u000a was performed while a color was held in VWM for a concurrent discrimination task. In the search task, participants were required\\u000a to foveate a cued item within a circular array of colored objects. During the saccade to the target, the array

  1. Phase Oscillatory Network and Visual Pattern Recognition.

    PubMed

    Follmann, Rosangela; Macau, Elbert E N; Rosa, Epaminondas; Piqueira, Jose R C

    2015-07-01

    We explore a properly interconnected set of Kuramoto type oscillators that results in a new associative-memory network configuration, which includes second- and third-order additional terms in the Fourier expansion of the network's coupling. Investigation of the response of the network to different external stimuli indicates an increase in the network capability for coding and information retrieval. Comparison of the network output with that of an equivalent experiment with subjects, for recognizing perturbed binary patterns, shows comparable results between the two approaches. We also discuss the enhanced storage capacity of the network. PMID:25137734

  2. Statistical Analysis of Visual Attentional Patterns for Video Surveillance

    E-print Network

    Cristani, Marco

    Statistical Analysis of Visual Attentional Patterns for Video Surveillance Giorgio Roffo , Marco activities. In this study, we consider 36 surveillance videos, organized in four categories (confront the advanced automated analysis of video surveil- lance footage, where machines imitate as best as possible

  3. Interactive visualization of design patterns can help in framework understanding

    Microsoft Academic Search

    Danny B. Lange; Yuichi Nakamura

    1995-01-01

    Framework programming is regarded as one the main advantages of object-oriented software engineering, and is expected to increase software reuse. In exploiting frameworks, however, programmers often face difficulties caused by the complexity of the hidden architecture and the multiplicity of the design decisions that are embedded in a framework. Interactive visualization of design patterns occurring in a framework shows how

  4. Top-down guidance in visual search for facial expressions

    Microsoft Academic Search

    Sowon Hahn; Scott D. Gronlund

    2007-01-01

    Using a visual search paradigm, we investigated how a top-down goal modified attentional bias for threatening facial expressions.\\u000a In two experiments, participants searched for a facial expression either based on stimulus characteristics or a top-down goal.\\u000a In Experiment 1, participants searched for a discrepant facial expression in a homogenous crowd of faces. Consistent with\\u000a previous research, we obtained a shallower

  5. Saccadic selection and crowding in visual search: stronger lateral masking leads to shorter search times

    Microsoft Academic Search

    Jelmer P. de Vries; Ignace T. C. Hooge; Marco A. Wiering; Frans A. J. Verstraten

    2011-01-01

    We investigated the role of crowding in saccadic selection during visual search. To guide eye movements, often information\\u000a from the visual periphery is used. Crowding is known to deteriorate the quality of peripheral information. In four search\\u000a experiments, we studied the role of crowding, by accompanying individual search elements by flankers. Varying the difference\\u000a between target and flankers allowed us

  6. Rapid and implicit effects of color category on visual search

    NASA Astrophysics Data System (ADS)

    Yokoi, Kenji; Watanabe, Katsumi; Saida, Shinya

    2012-07-01

    Many studies suggest that the color category influences visual perception. It is also well known that oculomotor control and visual attention are closely linked. In order to clarify temporal characteristics of color categorization, we investigated eye movements during color visual search. Eight color disks were presented briefly for 20-320 ms, and the subject was instructed to gaze at a target shown prior to the trial. We found that the color category of the target modulated eye movements significantly when the stimulus was displayed for more than 40 ms and the categorization could be completed within 80 ms. With the 20 ms presentation, the search performance was at a chance level, however, the first saccadic latency suggested that the color category had an effect on visual attention. These results suggest that color categorization affects the guidance of visual attention rapidly and implicitly.

  7. An initial search for visual overshadowing.

    PubMed

    Harris, Kevin R; Paul, Stephen T; Adams-Price, Carolyn E

    2012-01-01

    A consistent, albeit fragile, finding over the last couple of decades has been that verbalization of hard-to-verbalize stimuli, such as faces, interferes with subsequent recognition of the described target stimulus. We sought to elicit a similar phenomenon whereby visualization interferes with verbal recognition--that is, visual overshadowing. We randomly assigned participants (n?=?180) to either concrete (easy to visualize) or abstract (difficult to visualize) sentence conditions. Following presentation, participants were asked to verbalize the sentence, visualize the sentence, or work on a filler task. As predicted, visualization of an abstract verbal stimulus resulted in significantly lower recognition accuracy; unexpectedly, however, so did verbalization. The findings are discussed within the framework of fuzzy-trace theory. PMID:22502741

  8. The Serial Process in Visual Search

    ERIC Educational Resources Information Center

    Gilden, David L.; Thornton, Thomas L.; Marusich, Laura R.

    2010-01-01

    The conditions for serial search are described. A multiple target search methodology (Thornton & Gilden, 2007) is used to home in on the simplest target/distractor contrast that effectively mandates a serial scheduling of attentional resources. It is found that serial search is required when (a) targets and distractors are mirror twins, and (b)…

  9. Transcranial Magnetic Stimulation Reveals Attentional Feedback to Area V1 during Serial Visual Search

    E-print Network

    Paris-Sud XI, Université de

    during Serial Visual Search. PLoS ONE 6(5): e19712. doi:10.1371/journal.pone.0019712 Editor: Michael H (1980) [1], visual search experiments have been used to study attention [1­4]. Visual search tasksTranscranial Magnetic Stimulation Reveals Attentional Feedback to Area V1 during Serial Visual

  10. Processes influencing visual search efficiency in

    E-print Network

    Byrne, Mike

    Methods Participant results ACT-R model Model results Comparison Discussion Closing remarks 2 #12 inception, the ACT-R visual system hasn't really addressed these issues Currently doesn't handle bottom involved 14 #12;ACT-R Model Target rectangle encoded and placed in goal buffer +visual-location> requests

  11. Visual search for arbitrary objects in real scenes Jeremy M. Wolfe & George A. Alvarez &

    E-print Network

    . There is a vast literature on visual search for a target item among distracting items (for reviews, see SandersVisual search for arbitrary objects in real scenes Jeremy M. Wolfe & George A. Alvarez & Ruth. 2011 Abstract How efficient is visual search in real scenes? In searches for targets among arrays

  12. A Summary Statistic Representation in Peripheral Vision Explains Visual Search

    PubMed Central

    Rosenholtz, Ruth; Huang, Jie; Raj, Alvin; Balas, Benjamin J.; Ilie, Livia

    2014-01-01

    Vision is an active process: we repeatedly move our eyes to seek out objects of interest and explore our environment. Visual search experiments capture aspects of this process, by having subjects look for a target within a background of distractors. Search speed often correlates with target-distractor discriminability; search is faster when the target and distractors look quite different. However, there are notable exceptions. A given discriminability can yield efficient searches (where the target seems to “pop-out”) as well as inefficient ones (where additional distractors make search significantly slower and more difficult). Search is often more difficult when finding the target requires distinguishing a particular configuration or conjunction of features. Search asymmetries abound. These puzzling results have fueled three decades of theoretical and experimental studies. We argue that the key issue in search is the processing of image patches in the periphery, where visual representation is characterized by summary statistics computed over a sizable pooling region. By quantifying these statistics, we predict a set of classic search results, as well as peripheral discriminability of crowded patches such as those found in search displays. PMID:22523401

  13. A working memory account of refixations in visual search.

    PubMed

    Shen, Kelly; McIntosh, Anthony R; Ryan, Jennifer D

    2014-01-01

    We tested the hypothesis that active exploration of the visual environment is mediated not only by visual attention but also by visual working memory (VWM) by examining performance in both a visual search and a change detection task. Subjects rarely fixated previously examined distracters during visual search, suggesting that they successfully retained those items. Change detection accuracy decreased with increasing set size, suggesting that subjects had a limited VWM capacity. Crucially, performance in the change detection task predicted visual search efficiency: Higher VWM capacity was associated with faster and more accurate responses as well as lower probabilities of refixation. We found no temporal delay for return saccades, suggesting that active vision is primarily mediated by VWM rather than by a separate attentional disengagement mechanism commonly associated with the inhibition-of-return (IOR) effect. Taken together with evidence that visual attention, VWM, and the oculomotor system involve overlapping neural networks, these data suggest that there exists a general capacity for cognitive processing. PMID:25527149

  14. Using Pattern Search Methods for Surface Structure Determination of Nanomaterials

    E-print Network

    Lee, Jason R.

    Using Pattern Search Methods for Surface Structure Determination of Nanomaterials Zhengji Zhao High, especially in the case of nanomaterials. One of the most effective techniques for surface structure

  15. Signal detection evidence for limited capacity in visual search

    PubMed Central

    Fencsik, David E.; Flusberg, Stephen J.; Horowitz, Todd S.; Wolfe, Jeremy M.

    2014-01-01

    The nature of capacity limits (if any) in visual search has been a topic of controversy for decades. In 30 years of work, researchers have attempted to distinguish between two broad classes of visual search models. Attention-limited models have proposed two stages of perceptual processing: an unlimited-capacity preattentive stage, and a limited-capacity selective attention stage. Conversely, noise-limited models have proposed a single, unlimited-capacity perceptual processing stage, with decision processes influenced only by stochastic noise. Here, we use signal detection methods to test a strong prediction of attention-limited models. In standard attention-limited models, performance of some searches (feature searches) should only be limited by a preattentive stage. Other search tasks (e.g., spatial configuration search for a “2” among “5”s) should be additionally limited by an attentional bottleneck. We equated average accuracies for a feature and a spatial configuration search over set sizes of 1–8 for briefly presented stimuli. The strong prediction of attention-limited models is that, given overall equivalence in performance, accuracy should be better on the spatial configuration search than on the feature search for set size 1, and worse for set size 8. We confirm this crossover interaction and show that it is problematic for at least one class of one-stage decision models. PMID:21901574

  16. Visual Search Asymmetry with Uncertain Targets

    ERIC Educational Resources Information Center

    Saiki, Jun; Koike, Takahiko; Takahashi, Kohske; Inoue, Tomoko

    2005-01-01

    The underlying mechanism of search asymmetry is still unknown. Many computational models postulate top-down selection of target-defining features as a crucial factor. This feature selection account implies, and other theories implicitly assume, that predefined target identity is necessary for search asymmetry. The authors tested the validity of…

  17. Toward Visualization for Games: Theory, Design Space, and Patterns.

    PubMed

    Bowman, Brian; Elmqvist, Niklas; Jankun-Kelly, T J

    2012-02-29

    Electronic games are starting to incorporate in-game telemetry that collects data about player, team, and community performance on a massive scale, and as data begins to accumulate, so does the demand for effectively analyzing this data. In this paper, we use examples from both old and new games of different genres to explore the theory and design space of visualization for games. Drawing on these examples, we define a design space for this novel research topic and use it to formulate design patterns for how to best apply visualization technology to games. We then discuss the implications that this new framework will potentially have on the design and development of game and visualization technology in the future. PMID:22392715

  18. Visual search near threshold : some features are more equal than others

    Microsoft Academic Search

    Aave Hannus; Ronald van den Berg; Harold Bekkering; Jos B. T. M. Roerdink; Frans W. Cornelissen

    2006-01-01

    While searching for objects, we combine information from multiple visual modalities. Classical theories of visual search assume that features are processed independently prior to an integration stage. Based on this, one would predict that features that are equally discriminable in single feature search should remain so in conjunction search. We test this hypothesis by examining whether search accuracy in feature

  19. Electrophysiological Evidence of Semantic Interference in Visual Search

    Microsoft Academic Search

    Anna L. Telling; Sanjay Kumar; Antje S. Meyer; Glyn W. Humphreys

    2009-01-01

    Visual evoked responses were monitored while participants searched for a target (e.g.,bird) in a four-object display that could include a semantically related distractor (e.g., fish). The occurrence of both the target and the semantically related distractor modulated the N2pc response to the search display: The N2pc amplitude was more pronounced when the target and the distractor appeared in the same

  20. Visual search for arbitrary objects in real scenes

    Microsoft Academic Search

    Jeremy M. Wolfe; George A. Alvarez; Ruth Rosenholtz; Yoana I. Kuzmova; Ashley M. Sherman

    2011-01-01

    How efficient is visual search in real scenes? In searches for targets among arrays of randomly placed distractors, efficiency\\u000a is often indexed by the slope of the reaction time (RT) × Set Size function. However, it may be impossible to define set size\\u000a for real scenes. As an approximation, we hand-labeled 100 indoor scenes and used the number of labeled

  1. Electrophysiological Evidence of Semantic Interference in Visual Search

    Microsoft Academic Search

    Anna L. Telling; Sanjay Kumar; Antje S. Meyer; Glyn W. Humphreys

    2010-01-01

    Visual evoked responses were monitored while participants searched for a target(e.g.,bird) ina four-object display that could include a semantically related distractor (e.g., fish). The occur- rence of both the target and the semantically related distractor modulated the N2pc response to the search display: The N2pc amplitude was more pronounced when the target and the distrac- tor appeared in the same

  2. Visual Exploratory Search of Relationship Graphs on Smartphones

    PubMed Central

    Ouyang, Jianquan; Zheng, Hao; Kong, Fanbin; Liu, Tianming

    2013-01-01

    This paper presents a novel framework for Visual Exploratory Search of Relationship Graphs on Smartphones (VESRGS) that is composed of three major components: inference and representation of semantic relationship graphs on the Web via meta-search, visual exploratory search of relationship graphs through both querying and browsing strategies, and human-computer interactions via the multi-touch interface and mobile Internet on smartphones. In comparison with traditional lookup search methodologies, the proposed VESRGS system is characterized with the following perceived advantages. 1) It infers rich semantic relationships between the querying keywords and other related concepts from large-scale meta-search results from Google, Yahoo! and Bing search engines, and represents semantic relationships via graphs; 2) the exploratory search approach empowers users to naturally and effectively explore, adventure and discover knowledge in a rich information world of interlinked relationship graphs in a personalized fashion; 3) it effectively takes the advantages of smartphones’ user-friendly interfaces and ubiquitous Internet connection and portability. Our extensive experimental results have demonstrated that the VESRGS framework can significantly improve the users’ capability of seeking the most relevant relationship information to their own specific needs. We envision that the VESRGS framework can be a starting point for future exploration of novel, effective search strategies in the mobile Internet era. PMID:24223936

  3. Immediate Structured Visual Search for Medical Images

    E-print Network

    Kim, Tae-Kyun

    to a baseline. 1 Introduction The exponential growth of digital medical images of recent years poses both chal.g. an organ or anomaly), to search for ­ every region is searchable. Use cases include: conducting population

  4. How visual edge features influence cuttlefish camouflage patterning.

    PubMed

    Chiao, Chuan-Chin; Ulmer, Kimberly M; Siemann, Liese A; Buresch, Kendra C; Chubb, Charles; Hanlon, Roger T

    2013-05-01

    Rapid adaptive camouflage is the primary defense of soft-bodied cuttlefish. Previous studies have shown that cuttlefish body patterns are strongly influenced by visual edges in the substrate. The aim of the present study was to examine how cuttlefish body patterning is differentially controlled by various aspects of edges, including contrast polarity, contrast strength, and the presence or absence of "line terminators" introduced into a pattern when continuous edges are fragmented. Spatially high- and low-pass filtered white or black disks, as well as isolated, continuous and fragmented edges varying in contrast, were used to assess activation of cuttlefish skin components. Although disks of both contrast polarities evoked relatively weak disruptive body patterns, black disks activated different skin components than white disks, and high-frequency information alone sufficed to drive the responses to white disks whereas high- and low-frequency information were both required to drive responses to black disks. Strikingly, high-contrast edge fragments evoked substantially stronger body pattern responses than low-contrast edge fragments, whereas the body pattern responses evoked by high-contrast continuous edges were no stronger than those produced by low-contrast edges. This suggests that line terminators vs. continuous edges influence expression of disruptive body pattern components via different mechanisms that are controlled by contrast in different ways. PMID:23499977

  5. Reference effets -1-Asymmetries in Categorization, Perceptual Discrimination, and Visual Search for Reference and

    E-print Network

    Indiana University

    Reference effets -1- Asymmetries in Categorization, Perceptual Discrimination, and Visual Search;Reference effets -3- Asymmetries in Categorization, Perceptual Discrimination, and Visual Search; Livingston, Andrews, & Harnad, 1999) and addressed the consequences of this bias for memory (e.g., Corneille

  6. The nature of the visual environment induces implicit biases during language-mediated visual search

    Microsoft Academic Search

    Falk Huettig; James M. McQueen

    2011-01-01

    Four eyetracking experiments examined whether semantic and visual-shape representations are routinely retrieved from printed\\u000a word displays and used during language-mediated visual search. Participants listened to sentences containing target words\\u000a that were similar semantically or in shape to concepts invoked by concurrently displayed printed words. In Experiment 1, the displays contained semantic and shape competitors of the targets along with two

  7. VISUAL SALIENCY DOES NOT ACCOUNT FOR EYE MOVEMENTS DURING VISUAL SEARCH IN REAL-WORLD SCENES

    Microsoft Academic Search

    JOHN M. HENDERSON; JAMES R. BROCKMOLE; MONICA S. CASTELHANO; Michael Mack

    Abstract We tested the hypothesis that fixation locations during scene viewing,are primarily determined,by visual salience. Eye movements,were collected from participants who viewed photographs of real-world scenes during an active search task. Visual salience as determined by a popular computational,model did not predict region-to-region saccades or saccade sequences any better than did a random,model. Consistent with other reports in the literature,

  8. Selection-for-action in visual search

    Microsoft Academic Search

    Aave Hannus; Frans W. Cornelissen; Oliver Lindemann; Harold Bekkering

    2005-01-01

    Grasping an object rather than pointing to it enhances processing of its orientation but not its color. Apparently, visual discrimination is selectively enhanced for a behaviorally relevant feature. In two experiments we investigated the limitations and targets of this bias. Specifically, in Experiment 1 we were interested to find out whether the effect is capacity demanding, therefore we manipulated the

  9. Physiological Effect of Frequency of Illumination in Visual Search Task

    NASA Astrophysics Data System (ADS)

    Nozawa, Akio; Karita, Keita

    The objective of this study is to assess physiological effect of the frequency of illumination in a visual search task by physiological indices. Three types of a fluorescent light were tested, which were operated with DC, high-frequency AC, and commercial AC. As a result, significant differences on central and sympathetic nervous systems' activity were confirmed depending on the types of illumination.

  10. Enhancing Visual Search Abilities of People with Intellectual Disabilities

    ERIC Educational Resources Information Center

    Li-Tsang, Cecilia W. P.; Wong, Jackson K. K.

    2009-01-01

    This study aimed to evaluate the effects of cueing in visual search paradigm for people with and without intellectual disabilities (ID). A total of 36 subjects (18 persons with ID and 18 persons with normal intelligence) were recruited using convenient sampling method. A series of experiments were conducted to compare guided cue strategies using…

  11. Operator Choice Modeling for Collaborative UAV Visual Search Tasks

    E-print Network

    Cummings, Mary "Missy"

    Operator Choice Modeling for Collaborative UAV Visual Search Tasks Luca F. Bertuccelli Member, IEEE, and Mary L. Cummings Senior Member, IEEE Abstract--Unmanned Aerial Vehicles (UAVs) provide unprece- dented is expected to increase with envisaged future missions of one operator controlling mul- tiple UAVs

  12. Finding Wally: Prism adaptation improves visual search in chronic neglect

    Microsoft Academic Search

    Signe Vangkilde; Thomas Habekost

    2010-01-01

    Several studies have found that visuo-motor adaptation to rightward deviating prismatic goggles (prism adaptation) can alleviate symptoms of neglect after brain damage, but the long-term effect and clinical relevance of this rehabilitation approach have been questioned. In particular, the effect on visual search performance is controversial. In the present study 6 patients with chronic spatial neglect due to rightsided focal

  13. Fusing Concept Detection and Geo Context for Visual Search

    E-print Network

    Smeulders, Arnold

    Fusing Concept Detection and Geo Context for Visual Search Xirong Li Cees G.M. Snoek Marcel Worring Arnold W.M. Smeulders§ MOE Key Lab of Data Engineering and Knowledge Engineering, Renmin University.nl,m.worring@uva.nl,arnold.smeulders@cwi.nl ABSTRACT Given the proliferation of geo-tagged images, the question of how to exploit geo tags

  14. History effects in visual search for monsters: search times, choice biases, and liking.

    PubMed

    Chetverikov, Andrey; Kristjansson, Árni

    2015-02-01

    Repeating targets and distractors on consecutive visual search trials facilitates search performance, whereas switching targets and distractors harms search. In addition, search repetition leads to biases in free choice tasks, in that previously attended targets are more likely to be chosen than distractors. Another line of research has shown that attended items receive high liking ratings, whereas ignored distractors are rated negatively. Potential relations between the three effects are unclear, however. Here we simultaneously measured repetition benefits and switching costs for search times, choice biases, and liking ratings in color singleton visual search for "monster" shapes. We showed that if expectations from search repetition are violated, targets are liked to be less attended than otherwise. Choice biases were, on the other hand, affected by distractor repetition, but not by target/distractor switches. Target repetition speeded search times but had little influence on choice or liking. Our findings suggest that choice biases reflect distractor inhibition, and liking reflects the conflict associated with attending to previously inhibited stimuli, while speeded search follows both target and distractor repetition. Our results support the newly proposed affective-feedback-of-hypothesis-testing account of cognition, and additionally, shed new light on the priming of visual search. PMID:25338539

  15. Measuring Search Efficiency in Complex Visual Search Tasks: Global and Local Clutter

    ERIC Educational Resources Information Center

    Beck, Melissa R.; Lohrenz, Maura C.; Trafton, J. Gregory

    2010-01-01

    Set size and crowding affect search efficiency by limiting attention for recognition and attention against competition; however, these factors can be difficult to quantify in complex search tasks. The current experiments use a quantitative measure of the amount and variability of visual information (i.e., clutter) in highly complex stimuli (i.e.,…

  16. Visual search for natural grains in pigeons (Columba livia): Search images and selective attention

    Microsoft Academic Search

    Cynthia M. Langley; Donald A. Riley; Alan B. Bond; Namni Goel

    1996-01-01

    The experiments reported here were designed to test the suggestion of many researchers that selective attention to visual features of a prey can account for search-image effects. In 3 experiments pigeons ate wheat and vetch grains presented on multicolored and gray gravel trays. In Experiment 1 search-image effects were evident when grains were cryptic but not when they were conspicuous.

  17. Visual and memory search in complex environments: determinants of eye movements and search performance

    Microsoft Academic Search

    Lynn Huestegge; Ralph Radach

    2012-01-01

    Previous research on visual and memory search revealed various top down and bottom up factors influencing performance. However, utilising abstract stimuli (e.g. geometrical shapes or letters) and focussing on individual factors has often limited the applicability of research findings. Two experiments were designed to analyse which attributes of a product facilitate search in an applied environment. Participants scanned displays containing

  18. The role of memory for visual search in scenes.

    PubMed

    Le-Hoa Võ, Melissa; Wolfe, Jeremy M

    2015-03-01

    Many daily activities involve looking for something. The ease with which these searches are performed often allows one to forget that searching represents complex interactions between visual attention and memory. Although a clear understanding exists of how search efficiency will be influenced by visual features of targets and their surrounding distractors or by the number of items in the display, the role of memory in search is less well understood. Contextual cueing studies have shown that implicit memory for repeated item configurations can facilitate search in artificial displays. When searching more naturalistic environments, other forms of memory come into play. For instance, semantic memory provides useful information about which objects are typically found where within a scene, and episodic scene memory provides information about where a particular object was seen the last time a particular scene was viewed. In this paper, we will review work on these topics, with special emphasis on the role of memory in guiding search in organized, real-world scenes. PMID:25684693

  19. Visual search for arbitrary objects in real scenes

    PubMed Central

    Alvarez, George A.; Rosenholtz, Ruth; Kuzmova, Yoana I.; Sherman, Ashley M.

    2011-01-01

    How efficient is visual search in real scenes? In searches for targets among arrays of randomly placed distractors, efficiency is often indexed by the slope of the reaction time (RT) × Set Size function. However, it may be impossible to define set size for real scenes. As an approximation, we hand-labeled 100 indoor scenes and used the number of labeled regions as a surrogate for set size. In Experiment 1, observers searched for named objects (a chair, bowl, etc.). With set size defined as the number of labeled regions, search was very efficient (~5 ms/item). When we controlled for a possible guessing strategy in Experiment 2, slopes increased somewhat (~15 ms/item), but they were much shallower than search for a random object among other distinctive objects outside of a scene setting (Exp. 3: ~40 ms/item). In Experiments 4–6, observers searched repeatedly through the same scene for different objects. Increased familiarity with scenes had modest effects on RTs, while repetition of target items had large effects (>500 ms). We propose that visual search in scenes is efficient because scene-specific forms of attentional guidance can eliminate most regions from the “functional set size” of items that could possibly be the target. PMID:21671156

  20. Memory for Where, but Not What, Is Used During Visual Search

    Microsoft Academic Search

    Melissa R. Beck; Matthew S. Peterson; Miroslava Vomela

    2006-01-01

    Although the role of memory in visual search is debatable, most researchers agree with a limited-capacity model of memory in visual search. The authors demonstrate the role of memory by replicating previous findings showing that visual search is biased away from old items (previously examined items) and toward new items (nonexamined items). Furthermore, the authors examined the type of memory

  1. Visual search performance of patients with vision impairment: effect of JPEG image enhancement

    E-print Network

    Peli, Eli

    Visual search performance of patients with vision impairment: effect of JPEG image enhancement Gang & Peli E. Visual search performance of patients with vision impairment: effect of JPEG image enhancement, image enhancement, low vision rehabilitation, visual search Correspondence: Gang Luo E-mail address

  2. Use of an Augmented-Vision Device for Visual Search by Patients with Tunnel Vision

    E-print Network

    Peli, Eli

    Use of an Augmented-Vision Device for Visual Search by Patients with Tunnel Vision Gang Luo and Eli images over natural vision on visual search performance of patients with tunnel vision. METHODS. Twelve subjects with tunnel vision searched for targets presented outside their visual fields (VFs) on a blank

  3. Why are there eccentricity effects in visual search? Visual and attentional hypotheses

    Microsoft Academic Search

    Jeremy M. Wolfe; Patricia O’Neill; Sara C. Bennett

    1998-01-01

    In standard visual search experiments, observers search for a target item among distracting items. The locations of target\\u000a items are generally random within the display and ignored as a factor in data analysis. Previous work has shown that targets\\u000a presented near fixation are, in fact, found more efficiently than are targets presented at more peripheral locations. This\\u000a paper proposes that

  4. Eye movements during visual search in patients with glaucoma

    PubMed Central

    2012-01-01

    Background Glaucoma has been shown to lead to disability in many daily tasks including visual search. This study aims to determine whether the saccadic eye movements of people with glaucoma differ from those of people with normal vision, and to investigate the association between eye movements and impaired visual search. Methods Forty patients (mean age: 67 [SD: 9] years) with a range of glaucomatous visual field (VF) defects in both eyes (mean best eye mean deviation [MD]: –5.9 (SD: 5.4) dB) and 40 age-related people with normal vision (mean age: 66 [SD: 10] years) were timed as they searched for a series of target objects in computer displayed photographs of real world scenes. Eye movements were simultaneously recorded using an eye tracker. Average number of saccades per second, average saccade amplitude and average search duration across trials were recorded. These response variables were compared with measurements of VF and contrast sensitivity. Results The average rate of saccades made by the patient group was significantly smaller than the number made by controls during the visual search task (P?=?0.02; mean reduction of 5.6% (95% CI: 0.1 to 10.4%). There was no difference in average saccade amplitude between the patients and the controls (P?=?0.09). Average number of saccades was weakly correlated with aspects of visual function, with patients with worse contrast sensitivity (PR logCS; Spearman’s rho: 0.42; P?=?0.006) and more severe VF defects (best eye MD; Spearman’s rho: 0.34; P?=?0.037) tending to make less eye movements during the task. Average detection time in the search task was associated with the average rate of saccades in the patient group (Spearman’s rho?=??0.65; P?visual search by this group of patients was fewer than those made by people with normal vision of a similar average age. There was wide variability in saccade rate in the patients but there was an association between an increase in this measure and better performance in the search task. Assessment of eye movements in individuals with glaucoma might provide insight into the functional deficits of the disease. PMID:22937814

  5. The Mechanisms Underlying the ASD Advantage in Visual Search.

    PubMed

    Kaldy, Zsuzsa; Giserman, Ivy; Carter, Alice S; Blaser, Erik

    2013-10-01

    A number of studies have demonstrated that individuals with autism spectrum disorders (ASDs) are faster or more successful than typically developing control participants at various visual-attentional tasks (for reviews, see Dakin and Frith in Neuron 48:497-507, 2005; Simmons et al. in Vis Res 49:2705-2739, 2009). This "ASD advantage" was first identified in the domain of visual search by Plaisted et al. (J Child Psychol Psychiatry 39:777-783, 1998). Here we survey the findings of visual search studies from the past 15 years that contrasted the performance of individuals with and without ASD. Although there are some minor caveats, the overall consensus is that-across development and a broad range of symptom severity-individuals with ASD reliably outperform controls on visual search. The etiology of the ASD advantage has not been formally specified, but has been commonly attributed to 'enhanced perceptual discrimination', a superior ability to visually discriminate between targets and distractors in such tasks (e.g. O'Riordan in Cognition 77:81-96, 2000). As well, there is considerable evidence for impairments of the attentional network in ASD (for a review, see Keehn et al. in J Child Psychol Psychiatry 37:164-183, 2013). We discuss some recent results from our laboratory that support an attentional, rather than perceptual explanation for the ASD advantage in visual search. We speculate that this new conceptualization may offer a better understanding of some of the behavioral symptoms associated with ASD, such as over-focusing and restricted interests. PMID:24091470

  6. Video Google: Efficient Visual Search of Videos

    Microsoft Academic Search

    Josef Sivic; Andrew Zisserman

    2006-01-01

    We describe an approach to object retrieval which searches for and localizes all the occurrences of an object in a video, given a query image of the object. The object is represented by a set of viewpoint invariant region descriptors so that recognition can proceed successfully despite changes in viewpoint, illumination and partial occlusion. The temporal continuity of the video

  7. A mechanism for inhibition in visual search

    Microsoft Academic Search

    Jeff Moher; Howard E. Egeth

    2011-01-01

    Observers can use explicit foreknowledge of a feature of an upcoming target to guide search. However, little is known about observers' use of explicit foreknowledge that a specific feature will not match the upcoming target. In a series of experiments, we presented observers with either \\

  8. Adjustment of fixation duration in visual search

    Microsoft Academic Search

    Ignace Th. C. Hooge; Casper J. Erkelens

    1998-01-01

    To investigate whether fixation durations are adjusted to the duration of a foveal analysis task, we designed a search task in which each stimulus element yielded information about the position of the target. We asked subjects to look for the target by making eye movements in the direction indicated by each stimulus element. We explicitly asked the subjects to make

  9. Overlapping multivoxel patterns for two levels of visual expectation.

    PubMed

    de Gardelle, Vincent; Stokes, Mark; Johnen, Vanessa M; Wyart, Valentin; Summerfield, Christopher

    2013-01-01

    According to predictive accounts of perception, visual cortical regions encode sensory expectations about the external world, and the violation of those expectations by inputs (surprise). Here, using multi-voxel pattern analysis (MVPA) of functional magnetic resonance imaging (fMRI) data, we asked whether expectations and surprise activate the same pattern of voxels, in face-sensitive regions of the extra-striate visual cortex (the fusiform face area or FFA). Participants viewed pairs of repeating or alternating faces, with high or low probability of repetitions. As in previous studies, we found that repetition suppression (the attenuated BOLD response to repeated stimuli) in the FFA was more pronounced for probable repetitions, consistent with it reflecting reduced surprise to anticipated inputs. Secondly, we observed that repetition suppression and repetition enhancement responses were both consistent across scanner runs, suggesting that both have functional significance, with repetition enhancement possibly indicating the build up of sensory expectation. Critically, we also report that multi-voxels patterns associated with probability and repetition effects were significantly correlated within the left FFA. We argue that repetition enhancement responses and repetition probability effects can be seen as two types of expectation signals, occurring simultaneously, although at different processing levels (lower vs. higher), and different time scales (immediate vs. long term). PMID:23630488

  10. Visualizing patterns of craniofacial shape variation in Homo sapiens.

    PubMed

    Zollikofer, Christoph P E; Ponce De León, Marcia S

    2002-04-22

    The geometric morphometric analysis of shape variation in complex biological structures such as the human skull poses a number of specific challenges: the registration of homologous morphologies, the treatment of bilateral symmetry, the graphical representation of form variability in three dimensions and the interpretation of the results in terms of differential growth processes. To visualize complex patterns of shape change, we propose an alternative to classical Cartesian deformation grids in the style of D'Arcy W. Thompson. Reference to the surface structures of the organism under investigation permits a comprehensive visual grasp of shape change and its tentative interpretation in terms of differential growth. The application of this method to the analysis of human craniofacial shape variation reveals distinct modes of growth and development of the neurocranial and viscerocranial regions of the skull. Our data further indicate that variations in the orientation of the viscerocranium relative to the neurocranium impinge on the shapes of the face and the cranial vault. PMID:11958711

  11. Flow pattern visualization in a mimic anaerobic digester using CFD.

    PubMed

    Vesvikar, Mehul S; Al-Dahhan, Muthanna

    2005-03-20

    Three-dimensional steady-state computational fluid dynamics (CFD) simulations were performed in mimic anaerobic digesters to visualize their flow pattern and obtain hydrodynamic parameters. The mixing in the digester was provided by sparging gas at three different flow rates. The gas phase was simulated with air and the liquid phase with water. The CFD results were first evaluated using experimental data obtained by computer automated radioactive particle tracking (CARPT). The simulation results in terms of overall flow pattern, location of circulation cells and stagnant regions, trends of liquid velocity profiles, and volume of dead zones agree reasonably well with the experimental data. CFD simulations were also performed on different digester configurations. The effects of changing draft tube size, clearance, and shape of the tank bottoms were calculated to evaluate the effect of digester design on its flow pattern. Changing the draft tube clearance and height had no influence on the flow pattern or dead regions volume. However, increasing the draft tube diameter or incorporating a conical bottom design helped in reducing the volume of the dead zones as compared to a flat-bottom digester. The simulations showed that the gas flow rate sparged by a single point (0.5 cm diameter) sparger does not have an appreciable effect on the flow pattern of the digesters at the range of gas flow rates used. PMID:15685599

  12. Searching for pulsars using image pattern recognition

    SciTech Connect

    Zhu, W. W.; Berndsen, A.; Madsen, E. C.; Tan, M.; Stairs, I. H. [Department of Physics and Astronomy, 6224 Agricultural Road, University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada); Brazier, A. [Astronomy Department, Cornell University, Ithaca, NY 14853 (United States); Lazarus, P. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Lynch, R.; Scholz, P. [Department of Physics, McGill University, Montreal, QC H3A 2T8 (Canada); Stovall, K.; Cohen, S.; Dartez, L. P.; Lunsford, G.; Martinez, J. G.; Mata, A. [Center for Advanced Radio Astronomy, University of Texas at Brownsville, Brownsville, TX 78520 (United States); Ransom, S. M. [NRAO, Charlottesville, VA 22903 (United States); Banaszak, S.; Biwer, C. M.; Flanigan, J.; Rohr, M., E-mail: zhuww@phas.ubc.ca, E-mail: berndsen@phas.ubc.ca [Center for Gravitation, Cosmology and Astrophysics. University of Wisconsin Milwaukee, Milwaukee, WI 53211 (United States); and others

    2014-02-01

    In the modern era of big data, many fields of astronomy are generating huge volumes of data, the analysis of which can sometimes be the limiting factor in research. Fortunately, computer scientists have developed powerful data-mining techniques that can be applied to various fields. In this paper, we present a novel artificial intelligence (AI) program that identifies pulsars from recent surveys by using image pattern recognition with deep neural nets—the PICS (Pulsar Image-based Classification System) AI. The AI mimics human experts and distinguishes pulsars from noise and interference by looking for patterns from candidate plots. Different from other pulsar selection programs that search for expected patterns, the PICS AI is taught the salient features of different pulsars from a set of human-labeled candidates through machine learning. The training candidates are collected from the Pulsar Arecibo L-band Feed Array (PALFA) survey. The information from each pulsar candidate is synthesized in four diagnostic plots, which consist of image data with up to thousands of pixels. The AI takes these data from each candidate as its input and uses thousands of such candidates to train its ?9000 neurons. The deep neural networks in this AI system grant it superior ability to recognize various types of pulsars as well as their harmonic signals. The trained AI's performance has been validated with a large set of candidates from a different pulsar survey, the Green Bank North Celestial Cap survey. In this completely independent test, the PICS ranked 264 out of 277 pulsar-related candidates, including all 56 previously known pulsars and 208 of their harmonics, in the top 961 (1%) of 90,008 test candidates, missing only 13 harmonics. The first non-pulsar candidate appears at rank 187, following 45 pulsars and 141 harmonics. In other words, 100% of the pulsars were ranked in the top 1% of all candidates, while 80% were ranked higher than any noise or interference. The performance of this system can be improved over time as more training data are accumulated. This AI system has been integrated into the PALFA survey pipeline and has discovered six new pulsars to date.

  13. Searching for Pulsars Using Image Pattern Recognition

    NASA Astrophysics Data System (ADS)

    Zhu, W. W.; Berndsen, A.; Madsen, E. C.; Tan, M.; Stairs, I. H.; Brazier, A.; Lazarus, P.; Lynch, R.; Scholz, P.; Stovall, K.; Ransom, S. M.; Banaszak, S.; Biwer, C. M.; Cohen, S.; Dartez, L. P.; Flanigan, J.; Lunsford, G.; Martinez, J. G.; Mata, A.; Rohr, M.; Walker, A.; Allen, B.; Bhat, N. D. R.; Bogdanov, S.; Camilo, F.; Chatterjee, S.; Cordes, J. M.; Crawford, F.; Deneva, J. S.; Desvignes, G.; Ferdman, R. D.; Freire, P. C. C.; Hessels, J. W. T.; Jenet, F. A.; Kaplan, D. L.; Kaspi, V. M.; Knispel, B.; Lee, K. J.; van Leeuwen, J.; Lyne, A. G.; McLaughlin, M. A.; Siemens, X.; Spitler, L. G.; Venkataraman, A.

    2014-02-01

    In the modern era of big data, many fields of astronomy are generating huge volumes of data, the analysis of which can sometimes be the limiting factor in research. Fortunately, computer scientists have developed powerful data-mining techniques that can be applied to various fields. In this paper, we present a novel artificial intelligence (AI) program that identifies pulsars from recent surveys by using image pattern recognition with deep neural nets—the PICS (Pulsar Image-based Classification System) AI. The AI mimics human experts and distinguishes pulsars from noise and interference by looking for patterns from candidate plots. Different from other pulsar selection programs that search for expected patterns, the PICS AI is taught the salient features of different pulsars from a set of human-labeled candidates through machine learning. The training candidates are collected from the Pulsar Arecibo L-band Feed Array (PALFA) survey. The information from each pulsar candidate is synthesized in four diagnostic plots, which consist of image data with up to thousands of pixels. The AI takes these data from each candidate as its input and uses thousands of such candidates to train its ~9000 neurons. The deep neural networks in this AI system grant it superior ability to recognize various types of pulsars as well as their harmonic signals. The trained AI's performance has been validated with a large set of candidates from a different pulsar survey, the Green Bank North Celestial Cap survey. In this completely independent test, the PICS ranked 264 out of 277 pulsar-related candidates, including all 56 previously known pulsars and 208 of their harmonics, in the top 961 (1%) of 90,008 test candidates, missing only 13 harmonics. The first non-pulsar candidate appears at rank 187, following 45 pulsars and 141 harmonics. In other words, 100% of the pulsars were ranked in the top 1% of all candidates, while 80% were ranked higher than any noise or interference. The performance of this system can be improved over time as more training data are accumulated. This AI system has been integrated into the PALFA survey pipeline and has discovered six new pulsars to date.

  14. The long and the short of priming in visual search.

    PubMed

    Kruijne, Wouter; Meeter, Martijn

    2015-07-01

    Memory affects visual search, as is particularly evident from findings that when target features are repeated from one trial to the next, selection is faster. Two views have emerged on the nature of the memory representations and mechanisms that cause these intertrial priming effects: independent feature weighting versus episodic retrieval of previous trials. Previous research has attempted to disentangle these views focusing on short term effects. Here, we illustrate that the episodic retrieval models make the unique prediction of long-term priming: biasing one target type will result in priming of this target type for a much longer time, well after the bias has disappeared. We demonstrate that such long-term priming is indeed found for the visual feature of color, but only in conjunction search and not in singleton search. Two follow-up experiments showed that it was the kind of search (conjunction versus singleton) and not the difficulty, that determined whether long-term priming occurred. Long term priming persisted unaltered for at least 200 trials, and could not be explained as the result of explicit strategy. We propose that episodic memory may affect search more consistently than previously thought, and that the mechanisms for intertrial priming may be qualitatively different for singleton and conjunction search. PMID:25832185

  15. Do the Contents of Visual Working Memory Automatically Influence Attentional Selection During Visual Search?

    Microsoft Academic Search

    Geoffrey F. Woodman; Steven J. Luck

    2007-01-01

    In many theories of cognition, researchers propose that working memory and perception operate interactively. For example, in previous studies researchers have suggested that sensory inputs matching the contents of working memory will have an automatic advantage in the competition for processing resources. The authors tested this hypothesis by requiring observers to perform a visual search task while concurrently maintaining object

  16. Intertrial Temporal Contextual Cuing: Association Across Successive Visual Search Trials Guides Spatial Attention

    Microsoft Academic Search

    Fuminori Ono; Yuhong Jiang; Jun-ichiro Kawahara

    2005-01-01

    Contextual cuing refers to the facilitation of performance in visual search due to the repetition of the same displays. Whereas previous studies have focused on contextual cuing within single-search trials, this study tested whether 1 trial facilitates visual search of the next trial. Participants searched for a T among Ls. In the training phase, the spatial layout on trial N?1

  17. The Inferior Temporal Lobe Mediates Distracter-Resistant Visual Search of Patients with Spatial Neglect

    Microsoft Academic Search

    Radek Ptak; Nathalie Valenza

    2005-01-01

    Although impaired visual search is a core deficit of patients with spatial neglect, current evidence is not conclusive about the mechanisms underlying this failure. We present evidence from 14 neglect patients searching for a target defined by two perceptual features that visual search is mediated by mechanisms of attentional competition. Participants were tested in three search conditions with constant target

  18. Searching for Signs, Symbols, and Icons: Effects of Time of Day, Visual Complexity, and Grouping

    Microsoft Academic Search

    Siné McDougall; Victoria Tyrer; Simon Folkard

    2006-01-01

    Searching for icons, symbols, or signs is an integral part of tasks involving computer or radar displays, head-up displays in aircraft, or attending to road traffic signs. Icons therefore need to be designed to optimize search times, taking into account the factors likely to slow down visual search. Three factors likely to adversely affect visual search were examined: the time

  19. Why is visual search superior in autism spectrum disorder? Robert M. Joseph,1

    E-print Network

    underlies the superior visual search skills exhibited by individuals with autism spectrum disorder (ASD). WePAPER Why is visual search superior in autism spectrum disorder? Robert M. Joseph,1 Brandon Keehn,1) children in a standard static search task and a dynamic search task, in which targets and distractors

  20. [Visual search training for a case of homonymous field defect with multiple visual dysfunctions].

    PubMed

    Hirayama, Kazumi; Sakai, Shinya; Yamawaki, Rie; Kondo, Yumiko; Suzuki, Taemi; Fujimoto, Chiaki; Yamadori, Atsushi; Mori, Etsuro

    2004-05-01

    A 72-year-old right handed man developed right homonymous hemianopia without macular sparing, left homonymous lower quadranopia with macular sparing, cerebral amblyopia, cerebral achromatopsia, impaired form vision, and mild right hemispatial neglect, after multiple cerebral infarctions, involving bilateral occipital cortices. His intelligence and memory were deteriorated moderately. He failed to notice objects located in the affected visual field, because of his severely impaired visual search. When ordinary lighting was used, he showed severe right-sided omissions on the line cancellation test. However, omissions were less marked under the brighter lighting. By using a modified method of Kerkhoff and Vianen (1994), he was trained to make saccadic eye movements toward affected regions to find a target and to search and point at targets arranged randomly. As the sensitivity for contrast of isoluminante red and green stimuli was preserved well at high spatial frequencies despite the decreaced contrast sensitivity for brightness, we used green targets as the training stimuli. After the training, search field and pointing range that could be covered by the patient increased in size for both green and white targets, and daily activities improved. Moreover, after the training, he no longer showed discrepancy in line cancellation performances between ordinary and brighter lighting conditions. In the follow up period, the search field and the performance on the line cancellation test were maintained, while the performance of pointing targets array declined. The family members complained of mild re-deterioration of daily activities. Then, the training for searching and pointing re-introduced at home. After the training, his pointing performance and daily activities, evaluated by questionnaires to his family members, improved again. In conclusion, it was suggested that disordered visual search after a homonymous field defect can be treated effectively, even if multiple visual dysfunctions were associated. PMID:15279198

  1. Evolving the stimulus to fit the brain: a genetic algorithm reveals the brain's feature priorities in visual search.

    PubMed

    Van der Burg, Erik; Cass, John; Theeuwes, Jan; Alais, David

    2015-01-01

    How does the brain find objects in cluttered visual environments? For decades researchers have employed the classic visual search paradigm to answer this question using factorial designs. Although such approaches have yielded important information, they represent only a tiny fraction of the possible parametric space. Here we use a novel approach, by using a genetic algorithm (GA) to discover the way the brain solves visual search in complex environments, free from experimenter bias. Participants searched a series of complex displays, and those supporting fastest search were selected to reproduce (survival of the fittest). Their display properties (genes) were crossed and combined to create a new generation of "evolved" displays. Displays evolved quickly over generations towards a stable, efficiently searched array. Color properties evolved first, followed by orientation. The evolved displays also contained spatial patterns suggesting a coarse-to-fine search strategy. We argue that this behavioral performance-driven GA reveals the way the brain selects information during visual search in complex environments. We anticipate that our approach can be adapted to a variety of sensory and cognitive questions that have proven too intractable for factorial designs. PMID:25761347

  2. Time Course of Target Recognition in Visual Search

    PubMed Central

    Kotowicz, Andreas; Rutishauser, Ueli; Koch, Christof

    2009-01-01

    Visual search is a ubiquitous task of great importance: it allows us to quickly find the objects that we are looking for. During active search for an object (target), eye movements are made to different parts of the scene. Fixation locations are chosen based on a combination of information about the target and the visual input. At the end of a successful search, the eyes typically fixate on the target. But does this imply that target identification occurs while looking at it? The duration of a typical fixation (?170?ms) and neuronal latencies of both the oculomotor system and the visual stream indicate that there might not be enough time to do so. Previous studies have suggested the following solution to this dilemma: the target is identified extrafoveally and this event will trigger a saccade towards the target location. However this has not been experimentally verified. Here we test the hypothesis that subjects recognize the target before they look at it using a search display of oriented colored bars. Using a gaze-contingent real-time technique, we prematurely stopped search shortly after subjects fixated the target. Afterwards, we asked subjects to identify the target location. We find that subjects can identify the target location even when fixating on the target for less than 10?ms. Longer fixations on the target do not increase detection performance but increase confidence. In contrast, subjects cannot perform this task if they are not allowed to move their eyes. Thus, information about the target during conjunction search for colored oriented bars can, in some circumstances, be acquired at least one fixation ahead of reaching the target. The final fixation serves to increase confidence rather then performance, illustrating a distinct role of the final fixation for the subjective judgment of confidence rather than accuracy. PMID:20428512

  3. BATSE Gamma-Ray Burst Line Search. IV. Line Candidates from the Visual Search

    NASA Astrophysics Data System (ADS)

    Band, D. L.; Ryder, S.; Ford, L. A.; Matteson, J. L.; Palmer, D. M.; Teegarden, B. J.; Briggs, M. S.; Paciesas, W. S.; Pendleton, G. N.; Preece, R. D.

    1996-02-01

    We evaluate the significance of the line candidates identified by a visual search of burst spectra from BATSE's Spectroscopy Detectors. None of the candidates satisfy our detection criteria: an F-test probability less than 10-4 for a feature in one detector and consistency among the detectors that viewed the burst. Most of the candidates are not very significant and are likely to be fluctuations. Because of the expectation of finding absorption lines, the search was biased toward absorption features. We do not have a quantitative measure of the completeness of the search, which would enable a comparison with previous missions. Therefore, a more objective computerized search has begun.

  4. BATSE gamma-ray burst line search; 4, line candidates from the visual search

    E-print Network

    Band, D L; Ford, L A; Matteson, J L; Palmer, D M; Teegarden, B J; Briggs, M S; Paciesas, W S; Pendleton, G N; Preece, R D

    1995-01-01

    We evaluate the significance of the line candidates identified by a visual search of burst spectra from BATSE's Spectroscopy Detectors. None of the candidates satisfy our detection criteria: an F-test probability less than 10^-4 for a feature in one detector and consistency among the detectors which viewed the burst. Most of the candidates are not very significant, and are likely to be fluctuations. Because of the expectation of finding absorption lines, the search was biased towards absorption features. We do not have a quantitative measure of the completeness of the search which would enable a comparison with previous missions. Therefore a more objective computerized search has begun.

  5. Dynamic analysis and pattern visualization of forest fires.

    PubMed

    Lopes, António M; Tenreiro Machado, J A

    2014-01-01

    This paper analyses forest fires in the perspective of dynamical systems. Forest fires exhibit complex correlations in size, space and time, revealing features often present in complex systems, such as the absence of a characteristic length-scale, or the emergence of long range correlations and persistent memory. This study addresses a public domain forest fires catalogue, containing information of events for Portugal, during the period from 1980 up to 2012. The data is analysed in an annual basis, modelling the occurrences as sequences of Dirac impulses with amplitude proportional to the burnt area. First, we consider mutual information to correlate annual patterns. We use visualization trees, generated by hierarchical clustering algorithms, in order to compare and to extract relationships among the data. Second, we adopt the Multidimensional Scaling (MDS) visualization tool. MDS generates maps where each object corresponds to a point. Objects that are perceived to be similar to each other are placed on the map forming clusters. The results are analysed in order to extract relationships among the data and to identify forest fire patterns. PMID:25137393

  6. Dynamic Analysis and Pattern Visualization of Forest Fires

    PubMed Central

    Lopes, António M.; Tenreiro Machado, J. A.

    2014-01-01

    This paper analyses forest fires in the perspective of dynamical systems. Forest fires exhibit complex correlations in size, space and time, revealing features often present in complex systems, such as the absence of a characteristic length-scale, or the emergence of long range correlations and persistent memory. This study addresses a public domain forest fires catalogue, containing information of events for Portugal, during the period from 1980 up to 2012. The data is analysed in an annual basis, modelling the occurrences as sequences of Dirac impulses with amplitude proportional to the burnt area. First, we consider mutual information to correlate annual patterns. We use visualization trees, generated by hierarchical clustering algorithms, in order to compare and to extract relationships among the data. Second, we adopt the Multidimensional Scaling (MDS) visualization tool. MDS generates maps where each object corresponds to a point. Objects that are perceived to be similar to each other are placed on the map forming clusters. The results are analysed in order to extract relationships among the data and to identify forest fire patterns. PMID:25137393

  7. Tools for visualizing landscape pattern for large geographic areas

    SciTech Connect

    Timmins, S.P. [Analysas Corporation, Oak Ridge, TN (United States); Hunsaker, C.T. [Oak Ridge National Lab., TN (United States)

    1993-10-01

    Landscape pattern can be modelled on a grid with polygons constructed from cells that share edges. Although this model only allows connections in four directions, programming is convenient because both coordinates and attributes take discrete integer values. A typical raster land-cover data set is a multimegabyte matrix of byte values derived by classification of images or gridding of maps. Each matrix may have thousands of raster polygons (patches), many of them islands inside other larger patches. These data sets have complex topology that can overwhelm vector geographic information systems. The goal is to develop tools to quantify change in the landscape structure in terms of the shape and spatial distribution of patches. Three milestones toward this goal are (1) creating polygon topology on a grid, (2) visualizing patches, and (3) analyzing shape and pattern. An efficient algorithm has been developed to locate patches, measure area and perimeter, and establish patch topology. A powerful visualization system with an extensible programming language is used to write procedures to display images and perform analysis.

  8. Visualization of Orbits and Pattern Evocation for the Double Spherical Pendulum

    E-print Network

    Wendlandt, Jeff

    Visualization of Orbits and Pattern Evocation for the Double Spherical Pendulum Jerrold E. Marsden pattern evocation and the visualization of orbits of the double spherical pendulum. Pattern evocation or symmetry. Examples of this theory are demonstrated for the double spherical pendulum. A differential

  9. Visualization of Orbits and Pattern Evocation for the Double Spherical Pendulum

    E-print Network

    Marsden, Jerrold

    Visualization of Orbits and Pattern Evocation for the Double Spherical Pendulum Jerrold E. Marsden and the visualization of orbits of the double spherical pendulum. Pattern evocation is a phenomenon where patterns of this theory are demonstrated for the double spherical pendulum. A dierential-algebraic model is created

  10. Visual search for category sets: Tradeoffs between exploration and memory

    PubMed Central

    Kibbe, Melissa M.; Kowler, Eileen

    2012-01-01

    Limitations of working memory force a reliance on motor exploration to retrieve forgotten features of the visual array. A category search task was devised to study tradeoffs between exploration and memory in the face of significant cognitive and motor demands. The task required search through arrays of hidden, multi-featured objects to find three belonging to the same category. Location contents were revealed briefly by either a: (1) mouseclick, or (2) saccadic eye movement with or without delays between saccade offset and object appearance. As the complexity of the category rule increased, search favored exploration, with more visits and revisits needed to find the set. As motor costs increased (mouseclick search or oculomotor search with delays) search favored reliance on memory. Application of the model of J. Epelboim and P. Suppes (2001) to the revisits produced an estimate of immediate memory span (M) of about 4–6 objects. Variation in estimates of M across category rules suggested that search was also driven by strategies of transforming the category rule into concrete perceptual hypotheses. The results show that tradeoffs between memory and exploration in a cognitively demanding task are determined by continual and effective monitoring of perceptual load, cognitive demand, decision strategies and motor effort. PMID:21421747

  11. Serial Attention Mechanisms in Visual Search: A Direct Behavioral Demonstration

    Microsoft Academic Search

    Emanuela Bricolo; Tiziana Gianesini; Alessandra Fanini; Claus Bundesen; Leonardo Chelazzi

    2002-01-01

    In visual search, inefficient performance of human observers is typically characterized by a steady increase in reaction time with the number of array elementsthe so-called set-size effect. In general, set-size effects are taken to indicate that processing of the array elements depends on limited-capacity resources, that is, it involves attention. Contrasting theories have been proposed to account for this attentional

  12. Frame effects in visual search for line orientation

    Microsoft Academic Search

    Shuji Mori; Akihito Kataoka

    2004-01-01

    In the present study, we investigated the effects of surrounding frames on visual search for line orientation. Every line\\u000a item presented in the display was surrounded by a square frame of identical size and orientation. The orientations of the\\u000a frames, as well as those of the target and distractor lines, were either vertical or tilted. In six experiments, the surrounding

  13. Eye movements in active visual search: A computable phenomenological model

    Microsoft Academic Search

    T. D. Keech; L. Resca

    2010-01-01

    We present a computational model and corresponding computer simulations that mimic phenomenologically the eye movement trajectories\\u000a observed in a conjunctive visual search task. The element of randomness is captured in the model through a Monte Carlo selection\\u000a of a particular eye movement based on its probability, which depends on three factors, adjusted to match to the observed saccade\\u000a amplitude distribution,

  14. Spatial probability as an attentional cue in visual search

    Microsoft Academic Search

    Joy J. Geng; Marlene Behrmann

    2005-01-01

    We investigated the role of spatial probabilities in target location during participants’ performance of a visual search task.\\u000a Experiments 1 and 2 demonstrated that spatial probabilities could serve as a powerful attentional bias that produced faster\\u000a detection of targets in high-probability locations than of those in low- or random-probability locations. The effect could\\u000a not be explained by repetition priming alone.

  15. Size Matters: Large Objects Capture Attention in Visual Search

    Microsoft Academic Search

    Michael J. Proulx; Matthieu Louis

    2010-01-01

    Can objects or events ever capture one's attention in a purely stimulus-driven manner? A recent review of the literature set out the criteria required to find stimulus-driven attentional capture independent of goal-directed influences, and concluded that no published study has satisfied that criteria. Here visual search experiments assessed whether an irrelevantly large object can capture attention. Capture of attention by

  16. Reading and Visual Search: A Developmental Study in Normal Children

    PubMed Central

    Seassau, Magali; Bucci, Maria-Pia

    2013-01-01

    Studies dealing with developmental aspects of binocular eye movement behaviour during reading are scarce. In this study we have explored binocular strategies during reading and during visual search tasks in a large population of normal young readers. Binocular eye movements were recorded using an infrared video-oculography system in sixty-nine children (aged 6 to 15) and in a group of 10 adults (aged 24 to 39). The main findings are (i) in both tasks the number of progressive saccades (to the right) and regressive saccades (to the left) decreases with age; (ii) the amplitude of progressive saccades increases with age in the reading task only; (iii) in both tasks, the duration of fixations as well as the total duration of the task decreases with age; (iv) in both tasks, the amplitude of disconjugacy recorded during and after the saccades decreases with age; (v) children are significantly more accurate in reading than in visual search after 10 years of age. Data reported here confirms and expands previous studies on children's reading. The new finding is that younger children show poorer coordination than adults, both while reading and while performing a visual search task. Both reading skills and binocular saccades coordination improve with age and children reach a similar level to adults after the age of 10. This finding is most likely related to the fact that learning mechanisms responsible for saccade yoking develop during childhood until adolescence. PMID:23894627

  17. Development of a flow visualization apparatus. [to study convection flow patterns

    NASA Technical Reports Server (NTRS)

    Spradley, L. W.

    1975-01-01

    The use of an optical flow visualization device for studying convection flow patterns was investigated. The investigation considered use of a shadowgraph, schlieren and other means for visualizing the flow. A laboratory model was set up to provide data on the proper optics and photography procedures to best visualize the flow. A preliminary design of a flow visualization system is provided as a result of the study. Recommendations are given for a flight test program utilizing the flow visualization apparatus.

  18. Visual search in noise: Revealing the influence of structural cues by gaze-contingent

    E-print Network

    Field, David

    of real-world visual search. Despite the seemingly complex mechanisms underlying search, humans excel database query and data mining; image understanding; autonomous vehicle navigation; real-time, foveatedVisual search in noise: Revealing the influence of structural cues by gaze

  19. Searching for Signs, Symbols, and Icons: Effects of Time of Day, Visual Complexity, and Grouping

    ERIC Educational Resources Information Center

    McDougall, Sine; Tyrer, Victoria; Folkard, Simon

    2006-01-01

    Searching for icons, symbols, or signs is an integral part of tasks involving computer or radar displays, head-up displays in aircraft, or attending to road traffic signs. Icons therefore need to be designed to optimize search times, taking into account the factors likely to slow down visual search. Three factors likely to adversely affect visual

  20. Optimal feature gain modulation during visual search Vidhya Navalpakkam, Laurent Itti

    E-print Network

    Itti, Laurent

    Optimal feature gain modulation during visual search Vidhya Navalpakkam, Laurent Itti Dept Psychophysics experiments3 5 Discussion and Conclusion6Simulation Results4Formalizing visual search 1 2 Beware salience s i i b s search speed & accuracy TOP-DOWN BIAS Feature extraction Phase 2: Acquiring a belief

  1. A Minimal Model for Predicting Visual Search in Human-Computer Interaction

    E-print Network

    Hornof, Anthony

    A Minimal Model for Predicting Visual Search in Human-Computer Interaction Tim Halverson with and without a visual hierarchy and built computational cognitive models of the task. Hornof and Halverson [5

  2. QueryMarvel: A visual query language for temporal patterns using comic strips

    Microsoft Academic Search

    Jing Jin; Pedro A. Szekely

    2009-01-01

    In many domains, decision makers want to find and understand patterns of events as these patterns often give insight into the causal relationships among events. Current systems to specify patterns are either too difficult to use or only support simple patterns. We present QueryMarvel, an interactive visual query environment that allows ordinary users to easily and efficiently specify complex temporal

  3. How Temporal and Spatial Aspects of Presenting Visualizations Affect Learning about Locomotion Patterns

    ERIC Educational Resources Information Center

    Imhof, Birgit; Scheiter, Katharina; Edelmann, Jorg; Gerjets, Peter

    2012-01-01

    Two studies investigated the effectiveness of dynamic and static visualizations for a perceptual learning task (locomotion pattern classification). In Study 1, seventy-five students viewed either dynamic, static-sequential, or static-simultaneous visualizations. For tasks of intermediate difficulty, dynamic visualizations led to better…

  4. Participation of the thalamofugal visual pathway in a coarse pattern discrimination task in an open arena

    Microsoft Academic Search

    Cheri A. Budzynski; Verner P. Bingman

    2004-01-01

    The purpose of this study was to examine the role of the thalamofugal pathway in far-field visual processing. Experiment 1 examined the role of the visual wulst and the ectostriatum in a far-field pattern discrimination task in a large open arena. Control pigeons, pigeons with ectostriatum lesions, and pigeons with wulst lesions were trained to discriminate between four patterns within

  5. A visualized study of flow pattern and pressure distribution in a fluidic device

    Microsoft Academic Search

    Y. Nakayama; K. Ohta; K. Aoki; H. Ohta; M. Oki

    1981-01-01

    An attempt to define the flow pattern and pressure distribution in a wall attachment amplifier is reported. The pressure distribution was visualized using air as a working fluid and photographing with a Mach-Zehnder interferometer, using a supply pressure of 20,000 Pa. The flow pattern visualization was accomplished using the hydrogen bubble, tuft, surface floating, and suspension methods. The stream lines

  6. Memory under pressure: secondary-task effects on contextual cueing of visual search.

    PubMed

    Annac, Efsun; Manginelli, Angela A; Pollmann, Stefan; Shi, Zhuanghua; Müller, Hermann J; Geyer, Thomas

    2013-01-01

    Repeated display configurations improve visual search. Recently, the question has arisen whether this contextual cueing effect (Chun & Jiang, 1998) is itself mediated by attention, both in terms of selectivity and processing resources deployed. While it is accepted that selective attention modulates contextual cueing (Jiang & Leung, 2005), there is an ongoing debate whether the cueing effect is affected by a secondary working memory (WM) task, specifically at which stage WM influences the cueing effect: the acquisition of configural associations (e.g., Travis, Mattingley, & Dux, 2013) versus the expression of learned associations (e.g., Manginelli, Langer, Klose, & Pollmann, 2013). The present study re-investigated this issue. Observers performed a visual search in combination with a spatial WM task. The latter was applied on either early or late search trials--so as to examine whether WM load hampers the acquisition of or retrieval from contextual memory. Additionally, the WM and search tasks were performed either temporally in parallel or in succession--so as to permit the effects of spatial WM load to be dissociated from those of executive load. The secondary WM task was found to affect cueing in late, but not early, experimental trials--though only when the search and WM tasks were performed in parallel. This pattern suggests that contextual cueing involves a spatial WM resource, with spatial WM providing a workspace linking the current search array with configural long-term memory; as a result, occupying this workspace by a secondary WM task hampers the expression of learned configural associations. PMID:24190911

  7. Association and dissociation between detection and discrimination of objects of expertise: Evidence from visual search.

    PubMed

    Golan, Tal; Bentin, Shlomo; DeGutis, Joseph M; Robertson, Lynn C; Harel, Assaf

    2014-02-01

    Expertise in face recognition is characterized by high proficiency in distinguishing between individual faces. However, faces also enjoy an advantage at the early stage of basic-level detection, as demonstrated by efficient visual search for faces among nonface objects. In the present study, we asked (1) whether the face advantage in detection is a unique signature of face expertise, or whether it generalizes to other objects of expertise, and (2) whether expertise in face detection is intrinsically linked to expertise in face individuation. We compared how groups with varying degrees of object and face expertise (typical adults, developmental prosopagnosics [DP], and car experts) search for objects within and outside their domains of expertise (faces, cars, airplanes, and butterflies) among a variable set of object distractors. Across all three groups, search efficiency (indexed by reaction time slopes) was higher for faces and airplanes than for cars and butterflies. Notably, the search slope for car targets was considerably shallower in the car experts than in nonexperts. Although the mean face slope was slightly steeper among the DPs than in the other two groups, most of the DPs' search slopes were well within the normative range. This pattern of results suggests that expertise in object detection is indeed associated with expertise at the subordinate level, that it is not specific to faces, and that the two types of expertise are distinct facilities. We discuss the potential role of experience in bridging between low-level discriminative features and high-level naturalistic categories. PMID:24338355

  8. Visual search and location probability learning from variable perspectives.

    PubMed

    Jiang, Yuhong V; Swallow, Khena M; Capistrano, Christian G

    2013-01-01

    Do moving observers code attended locations relative to the external world or relative to themselves? To address this question we asked participants to conduct visual search on a tabletop. The search target was more likely to occur in some locations than others. Participants walked to different sides of the table from trial to trial, changing their perspective. The high-probability locations were stable on the tabletop but variable relative to the viewer. When participants were informed of the high-probability locations, search was faster when the target was in those locations, demonstrating probability cuing. However, in the absence of explicit instructions and awareness, participants failed to acquire an attentional bias toward the high-probability locations even when the search items were displayed over an invariant natural scene. Additional experiments showed that locomotion did not interfere with incidental learning, but the lack of a consistent perspective prevented participants from acquiring probability cuing incidentally. We conclude that spatial biases toward target-rich locations are directed by two mechanisms: incidental learning and goal-driven attention. Incidental learning codes attended locations in a viewer-centered reference frame and is not updated with viewer movement. Goal-driven attention can be deployed to prioritize an environment-rich region. PMID:23716120

  9. CuZero: embracing the frontier of interactive visual search for informed users

    Microsoft Academic Search

    Eric Zavesky; Shih-fu Chang

    2008-01-01

    Users of most visual search systems suer from two pri- mary sources of frustration. Before a search over this data is executed, a query must be formulated. Traditional key- word search systems oer only passive, non-interactive in- put, which frustrates users that are unfamiliar with the search topic or the target data set. Additionally, after query formulation, result inspection is

  10. Visual height intolerance and acrophobia: clinical characteristics and comorbidity patterns.

    PubMed

    Kapfhammer, Hans-Peter; Huppert, Doreen; Grill, Eva; Fitz, Werner; Brandt, Thomas

    2015-08-01

    The purpose of this study was to estimate the general population lifetime and point prevalence of visual height intolerance and acrophobia, to define their clinical characteristics, and to determine their anxious and depressive comorbidities. A case-control study was conducted within a German population-based cross-sectional telephone survey. A representative sample of 2,012 individuals aged 14 and above was selected. Defined neurological conditions (migraine, Menière's disease, motion sickness), symptom pattern, age of first manifestation, precipitating height stimuli, course of illness, psychosocial impairment, and comorbidity patterns (anxiety conditions, depressive disorders according to DSM-IV-TR) for vHI and acrophobia were assessed. The lifetime prevalence of vHI was 28.5 % (women 32.4 %, men 24.5 %). Initial attacks occurred predominantly (36 %) in the second decade. A rapid generalization to other height stimuli and a chronic course of illness with at least moderate impairment were observed. A total of 22.5 % of individuals with vHI experienced the intensity of panic attacks. The lifetime prevalence of acrophobia was 6.4 % (women 8.6 %, men 4.1 %), and point prevalence was 2.0 % (women 2.8 %; men 1.1 %). VHI and even more acrophobia were associated with high rates of comorbid anxious and depressive conditions. Migraine was both a significant predictor of later acrophobia and a significant consequence of previous acrophobia. VHI affects nearly a third of the general population; in more than 20 % of these persons, vHI occasionally develops into panic attacks and in 6.4 %, it escalates to acrophobia. Symptoms and degree of social impairment form a continuum of mild to seriously distressing conditions in susceptible subjects. PMID:25262317

  11. The Parameters of Pattern Visual Evoked Potential in the Severe Visual Loss Patients in Korean

    PubMed Central

    Kim, Min Kyung

    2015-01-01

    Purpose To compare the characteristics of the pattern visual evoked potential (PVEP) in patients with severe visual loss and normal controls, and to demonstrate the range of PVEP parameters in normal Koreans. Methods The patients were divided into three groups according to visual acuity: group 1, ranging from no light perception to less than 0.02; group 2, ranging from 0.02 to 0.1; and group 3, ranging from 0.125 to 0.25. Group 4 was established as a healthy control group. The 95% confidence intervals (CIs) of the PVEP parameters were calculated for group 4. The PVEP parameters were compared among these four groups, and the amplitudes were evaluated with respect to the 95% CIs. We used the area under the curve to integrate the sensitivity and the specificity of the PVEP parameter quantitative values (7.01 to 9.57 µV and 6.75 to 10.11 µV). Results A total of 101 eyes were investigated. The 95% CIs of the P100 and N135 amplitudes of group 4 were 7.01 to 9.57 µV and 6.75 to 10.11 µV, respectively. The amplitudes of P100 and N135 were significantly higher in group 4 (p < 0.001). The P100 and N135 amplitude were below the 95% CI in all group 1 patients. The area under the curve of the P100 amplitude was the highest (0.789). Conclusions No legally blind patient in the present study exhibited a value within the 95% CI of the controls. The P100 amplitude may be the best parameter for defining blindness in patients. PMID:26028947

  12. Adaptation of video game UVW mapping to 3D visualization of gene expression patterns

    NASA Astrophysics Data System (ADS)

    Vize, Peter D.; Gerth, Victor E.

    2007-01-01

    Analysis of gene expression patterns within an organism plays a critical role in associating genes with biological processes in both health and disease. During embryonic development the analysis and comparison of different gene expression patterns allows biologists to identify candidate genes that may regulate the formation of normal tissues and organs and to search for genes associated with congenital diseases. No two individual embryos, or organs, are exactly the same shape or size so comparing spatial gene expression in one embryo to that in another is difficult. We will present our efforts in comparing gene expression data collected using both volumetric and projection approaches. Volumetric data is highly accurate but difficult to process and compare. Projection methods use UV mapping to align texture maps to standardized spatial frameworks. This approach is less accurate but is very rapid and requires very little processing. We have built a database of over 180 3D models depicting gene expression patterns mapped onto the surface of spline based embryo models. Gene expression data in different models can easily be compared to determine common regions of activity. Visualization software, both Java and OpenGL optimized for viewing 3D gene expression data will also be demonstrated.

  13. Pattern masking investigations of the second-order visual mechanisms

    NASA Astrophysics Data System (ADS)

    Huang, Pi-Chun; Chen, Chien-Chung

    2009-02-01

    Human visual system is sensitive to both the first-order and the second-order variations in an image. The latter one is especially important for the digital image processing as it allows human observers to perceive the envelope of the pixel intensities as smooth surface instead of the discrete pixels. Here we used pattern masking paradigm to measure the detection threshold of contrast modulated (CM) stimuli, which comprise the modulation of the contrast of horizontal gratings by a vertical Gabor function, under different modulation depth of the CM stimuli. The threshold function showed a typical dipper shape: the threshold decreased with modulation depth (facilitation) at low pedestal depth modulations and then increased (suppression) at high pedestal modulation. The data was well explained by a modified divisive inhibition model that operated both on depth modulation and carrier contrast in the input images. Hence the divisive inhibition, determined by both the first- and the second-order information in the stimuli, is necessary to explain the discrimination between two second-order stimuli.

  14. Mouse Visual Neocortex Supports Multiple Stereotyped Patterns of Microcircuit Activity

    PubMed Central

    Sadovsky, Alexander J.

    2014-01-01

    Spiking correlations between neocortical neurons provide insight into the underlying synaptic connectivity that defines cortical microcircuitry. Here, using two-photon calcium fluorescence imaging, we observed the simultaneous dynamics of hundreds of neurons in slices of mouse primary visual cortex (V1). Consistent with a balance of excitation and inhibition, V1 dynamics were characterized by a linear scaling between firing rate and circuit size. Using lagged firing correlations between neurons, we generated functional wiring diagrams to evaluate the topological features of V1 microcircuitry. We found that circuit connectivity exhibited both cyclic graph motifs, indicating recurrent wiring, and acyclic graph motifs, indicating feedforward wiring. After overlaying the functional wiring diagrams onto the imaged field of view, we found properties consistent with Rentian scaling: wiring diagrams were topologically efficient because they minimized wiring with a modular architecture. Within single imaged fields of view, V1 contained multiple discrete circuits that were overlapping and highly interdigitated but were still distinct from one another. The majority of neurons that were shared between circuits displayed peri-event spiking activity whose timing was specific to the active circuit, whereas spike times for a smaller percentage of neurons were invariant to circuit identity. These data provide evidence that V1 microcircuitry exhibits balanced dynamics, is efficiently arranged in anatomical space, and is capable of supporting a diversity of multineuron spike firing patterns from overlapping sets of neurons. PMID:24899701

  15. Immaturity of the Oculomotor Saccade and Vergence Interaction in Dyslexic Children: Evidence from a Reading and Visual Search Study

    PubMed Central

    Bucci, Maria Pia; Nassibi, Naziha; Gerard, Christophe-Loic; Bui-Quoc, Emmanuel; Seassau, Magali

    2012-01-01

    Studies comparing binocular eye movements during reading and visual search in dyslexic children are, at our knowledge, inexistent. In the present study we examined ocular motor characteristics in dyslexic children versus two groups of non dyslexic children with chronological/reading age-matched. Binocular eye movements were recorded by an infrared system (mobileEBT®, e(ye)BRAIN) in twelve dyslexic children (mean age 11 years old) and a group of chronological age-matched (N?=?9) and reading age-matched (N?=?10) non dyslexic children. Two visual tasks were used: text reading and visual search. Independently of the task, the ocular motor behavior in dyslexic children is similar to those reported in reading age-matched non dyslexic children: many and longer fixations as well as poor quality of binocular coordination during and after the saccades. In contrast, chronological age-matched non dyslexic children showed a small number of fixations and short duration of fixations in reading task with respect to visual search task; furthermore their saccades were well yoked in both tasks. The atypical eye movement's patterns observed in dyslexic children suggest a deficiency in the visual attentional processing as well as an immaturity of the ocular motor saccade and vergence systems interaction. PMID:22438934

  16. How fast can you change your mind? The speed of top-down guidance in visual search

    Microsoft Academic Search

    Jeremy M. Wolfe; Todd S. Horowitz; Naomi Kenner; Megan Hyle; Nina Vasan

    2004-01-01

    Most laboratory visual search tasks involve many searches for the same target, while in the real world we typically change our target with each search (e.g. find the coffee cup, then the sugar). How quickly can the visual system be reconfigured to search for a new target? Here observers searched for targets specified by cues presented at different SOAs relative

  17. Inhibition and anticipation in visual search: Evidence from effects of color foreknowledge on preview search

    Microsoft Academic Search

    Jason J. Braithwaite; Glyn W. Humphreys

    2003-01-01

    We present four experiments in which we examined the effects of color mixing andprior target color knowledge on preview search (Watson & Humphreys, 1997). The task was to detect a target letter (an N or a Z)\\u000a that appeared along with other new letters, when old distractors remained in the visual field. In some conditions, participants\\u000a were told the target’s

  18. Adaptation of video game UVW mapping to 3D visualization of gene expression patterns

    E-print Network

    Vize, Peter D.

    Adaptation of video game UVW mapping to 3D visualization of gene expression patterns Peter D. Vize University Drive NW, Calgary, Alberta T2N1N4, Canada ABSTRACT Analysis of gene expression patterns within. During embryonic development the analysis and comparison of different gene expression patterns allows

  19. Query suggestions for mobile search: understanding usage patterns

    Microsoft Academic Search

    Maryam Kamvar; Shumeet Baluja

    2008-01-01

    Entering search terms on mobile phones is a time consuming and cumbersome task. In this paper, we explore the usage patterns of query entry interfaces that display suggestions. Our primary goal is to build a usage model of query suggestions in order to provide user interface guidelines for mobile text prediction interfaces. We find that users who were asked to

  20. Is There a Limit to the Superiority of Individuals with ASD in Visual Search?

    ERIC Educational Resources Information Center

    Hessels, Roy S.; Hooge, Ignace T. C.; Snijders, Tineke M.; Kemner, Chantal

    2014-01-01

    Superiority in visual search for individuals diagnosed with autism spectrum disorder (ASD) is a well-reported finding. We administered two visual search tasks to individuals with ASD and matched controls. One showed no difference between the groups, and one did show the expected superior performance for individuals with ASD. These results offer an…

  1. Analysis and modeling of fixation point selection for visual search in cluttered backgrounds

    Microsoft Academic Search

    Magnus Snorrason; James Hoffman; Harald Ruda

    2000-01-01

    Hard-to-see targets are generally only detected by human observers once they have been fixated. Hence, understanding how the human visual system allocates fixation locations is necessary for predicting target detectability. Visual search experiments were conducted where observers searched for military vehicles in cluttered terrain. Instantaneous eye position measurements were collected using an eye tracker. The resulting data was partitioned into

  2. Area activation: a computational model of saccadic selectivity in visual search

    Microsoft Academic Search

    Marc Pomplun; Eyal M. Reingold; Jiye Shen

    2003-01-01

    The Area Activation Model (Pomplun, Reingold, Shen, & Williams, 2000) is a computational model predicting the statistical distribution of saccadic endpoints in visual search tasks. Its basic assumption is that saccades in visual search tend to foveate display areas that provide a maximum amount of task- relevant information for processing during the subsequent fixation. In the present study, a counterintuitive

  3. Visual search in dynamic 3D visualisations of unstructured picture collections

    Microsoft Academic Search

    Olivier Christmann; Noëlle Carbonell; Simon Richir

    2010-01-01

    We present two empirical studies of visual search in dynamic 3D visualisations of large, randomly ordered, photo collections. The aim is to assess the possible effects of geometrical distortions on visual search effectiveness, efficiency and comfort, by comparing the influence of two perspective representations of photo collections on participants’ performance results and subjective judgments. Thumbnails of the 1000 or so

  4. The Effect of Animated Banner Advertisements on a Visual Search Task

    E-print Network

    Hornof, Anthony

    distracted by animation and subjectively believe that their performance suffers when flashing objects Animation, visual search, banner advertisements, flashing INTRODUCTION As processor and Internet connectionThe Effect of Animated Banner Advertisements on a Visual Search Task Moira Burke and Anthony J

  5. Toddlers with Autism Spectrum Disorder Are More Successful at Visual Search than Typically Developing Toddlers

    ERIC Educational Resources Information Center

    Kaldy, Zsuzsa; Kraper, Catherine; Carter, Alice S.; Blaser, Erik

    2011-01-01

    Plaisted, O'Riordan and colleagues (Plaisted, O'Riordan & Baron-Cohen, 1998; O'Riordan, 2004) showed that school-age children and adults with Autism Spectrum Disorder (ASD) are faster at finding targets in certain types of visual search tasks than typical controls. Currently though, there is very little known about the visual search skills of very…

  6. Bicycle accidents and drivers' visual search at left and right turns.

    PubMed

    Summala, H; Pasanen, E; Räsänen, M; Sievänen, J

    1996-03-01

    The accident data base of the City of Helsinki shows that when drivers cross a cycle path as they enter a non-signalized intersection, the clearly dominant type of car-cycle crashes is that in which a cyclist comes from the right and the driver is turning right, in marked contrast to the cases with drivers turning left (Pasanen 1992; City of Helsinki, Traffic Planning Department, Report L4). This study first tested an explanation that drivers turning right simply focus their attention on the cars coming from the left-those coming from the right posing no threat to them-and fail to see the cyclist from the right early enough. Drivers' scanning behavior was studied at two T-intersections. Two well-hidden video cameras were used, one to measure the head movements of the approaching drivers and the other one to measure speed and distance from the cycle crossroad. The results supported the hypothesis: the drivers turning right scanned the right leg of the T-intersection less frequently and later than those turning left. Thus, it appears that drivers develop a visual scanning strategy which concentrates on detection of more frequent and major dangers but ignores and may even mask visual information on less frequent dangers. The second part of the study evaluated different countermeasures, including speed humps, in terms of drivers' visual search behavior. The results suggested that speed-reducing countermeasures changed drivers' visual search patterns in favor of the cyclists coming from the right, presumably at least in part due to the fact that drivers were simply provided with more time to focus on each direction. PMID:8703272

  7. Visualization of search results: a comparative evaluation of text, 2D, and 3D interfaces

    Microsoft Academic Search

    Marc M. Sebrechts; John V. Cugini; Sharon J. Laskowski; Joanna Vasilakis; Michael S. Miller

    1999-01-01

    Although there have been many prototypes of visualization in support of information retrieval, there has been little systematic evaluation that distinguishes the benefits of the visualization per se from that of various accompanying features. The current study focuses on such an evaluation of NIRVE, a tool that supports visualization of search results. Insofar as possible, functionally equivalent 3D, 2D, and

  8. Perceptual Encoding Efficiency in Visual Search Robert Rauschenberger and Steven Yantis

    E-print Network

    Yantis, Steven

    - tance as a basic cognitive task. Often overlooked, however, is the reason why visual search is so interesting to begin with: It is arguably one of the most basic of visual behaviors. Even during apparently by the idea that the visual system cannot represent all possible com- binations of basic features in parallel

  9. Visual Working Memory Supports the Inhibition of Previously Processed Information: Evidence from Preview Search

    ERIC Educational Resources Information Center

    Al-Aidroos, Naseem; Emrich, Stephen M.; Ferber, Susanne; Pratt, Jay

    2012-01-01

    In four experiments we assessed whether visual working memory (VWM) maintains a record of previously processed visual information, allowing old information to be inhibited, and new information to be prioritized. Specifically, we evaluated whether VWM contributes to the inhibition (i.e., visual marking) of previewed distractors in a preview search.…

  10. Visual Search in Typically Developing Toddlers and Toddlers with Fragile X or Williams Syndrome

    ERIC Educational Resources Information Center

    Scerif, Gaia; Cornish, Kim; Wilding, John; Driver, Jon; Karmiloff-Smith, Annette

    2004-01-01

    Visual selective attention is the ability to attend to relevant visual information and ignore irrelevant stimuli. Little is known about its typical and atypical development in early childhood. Experiment 1 investigates typically developing toddlers' visual search for multiple targets on a touch-screen. Time to hit a target, distance between…

  11. Relationships among balance, visual search, and lacrosse-shot accuracy.

    PubMed

    Marsh, Darrin W; Richard, Leon A; Verre, Arlene B; Myers, Jay

    2010-06-01

    The purpose of this study was to examine variables that may contribute to shot accuracy in women's college lacrosse. A convenience sample of 15 healthy women's National Collegiate Athletic Association Division III College lacrosse players aged 18-23 (mean+/-SD, 20.27+/-1.67) participated in the study. Four experimental variables were examined: balance, visual search, hand grip strength, and shoulder joint position sense. Balance was measured by the Biodex Stability System (BSS), and visual search was measured by the Trail-Making Test Part A (TMTA) and Trail-Making Test Part B (TMTB). Hand-grip strength was measured by a standard hand dynamometer, and shoulder joint position sense was measured using a modified inclinometer. All measures were taken in an indoor setting. These experimental variables were then compared with lacrosse-shot error that was measured indoors using a high-speed video camera recorder and a specialized L-shaped apparatus. A Stalker radar gun measured lacrosse-shot velocity. The mean lacrosse-shot error was 15.17 cm with a mean lacrosse-shot velocity of 17.14 m.s (38.35 mph). Lower scores on the BSS level 8 eyes open (BSS L8 E/O) test and TMTB were positively related to less lacrosse-shot error (r=0.760, p=0.011) and (r=0.519, p=0.048), respectively. Relations were not significant between lacrosse-shot error and grip strength (r=0.191, p = 0.496), lacrosse-shot error and BSS level 8 eyes closed (BSS L8 E/C) (r=0.501, p=0.102), lacrosse-shot error and BSS level 4 eyes open (BSS L4 E/O) (r=0.313, p=0.378), lacrosse-shot error and BSS level 4 eyes closed (BSS L4 E/C) (r=-0.029, p=0.936) lacrosse-shot error and shoulder joint position sense (r=-0.509, p=0.055) and between lacrosse-shot error and TMTA (r=0.375, p=0.168). The results reveal that greater levels of shot accuracy may be related to greater levels of visual search and balance ability in women college lacrosse athletes. PMID:20508452

  12. Navigation and Search in 3D Visualizations of Large Unstructured Photo Collections: An Empirical Study

    Microsoft Academic Search

    Olivier Christmann; Noëlle Carbonell

    2008-01-01

    We present an empirical study which aims at assessing the effects of dynamic 3D visualizations of randomly ordered photo collections\\u000a on visual search effectiveness, efficiency and comfort. 20 participants performed visual search tasks in collections of about\\u000a 1000 colour photos using 2 perspective views of a vertical cylinder: thumbnails were displayed on its lateral surface either\\u000a on the inside (IV)

  13. Strategies of the honeybee Apis mellifera during visual search for vertical targets presented at various heights: a role for spatial attention?

    PubMed Central

    Morawetz, Linde; Chittka, Lars; Spaethe, Johannes

    2014-01-01

    When honeybees are presented with a colour discrimination task, they tend to choose swiftly and accurately when objects are presented in the ventral part of their frontal visual field. In contrast, poor performance is observed when objects appear in the dorsal part. Here we investigate if this asymmetry is caused by fixed search patterns or if bees can use alternative search mechanisms such as spatial attention, which allows flexible focusing on different areas of the visual field. We asked individual honeybees to choose an orange rewarded target among blue distractors. Target and distractors were presented in the ventral visual field, the dorsal field or both. Bees presented with targets in the ventral visual field consistently had the highest search efficiency, with rapid decisions, high accuracy and direct flight paths. In contrast, search performance for dorsally located targets was inaccurate and slow at the beginning of the test phase, but bees increased their search performance significantly after a few learning trials: they found the target faster, made fewer errors and flew in a straight line towards the target. However, bees needed thrice as long to improve the search for a dorsally located target when the target’s position changed randomly between the ventral and the dorsal visual field. We propose that honeybees form expectations of the location of the target’s appearance and adapt their search strategy accordingly. Different possible mechanisms of this behavioural adaptation are discussed. PMID:25254109

  14. Strategies of the honeybee Apis mellifera during visual search for vertical targets presented at various heights: a role for spatial attention?

    PubMed

    Morawetz, Linde; Chittka, Lars; Spaethe, Johannes

    2014-01-01

    When honeybees are presented with a colour discrimination task, they tend to choose swiftly and accurately when objects are presented in the ventral part of their frontal visual field. In contrast, poor performance is observed when objects appear in the dorsal part. Here we investigate if this asymmetry is caused by fixed search patterns or if bees can use alternative search mechanisms such as spatial attention, which allows flexible focusing on different areas of the visual field. We asked individual honeybees to choose an orange rewarded target among blue distractors. Target and distractors were presented in the ventral visual field, the dorsal field or both. Bees presented with targets in the ventral visual field consistently had the highest search efficiency, with rapid decisions, high accuracy and direct flight paths. In contrast, search performance for dorsally located targets was inaccurate and slow at the beginning of the test phase, but bees increased their search performance significantly after a few learning trials: they found the target faster, made fewer errors and flew in a straight line towards the target. However, bees needed thrice as long to improve the search for a dorsally located target when the target's position changed randomly between the ventral and the dorsal visual field. We propose that honeybees form expectations of the location of the target's appearance and adapt their search strategy accordingly. Different possible mechanisms of this behavioural adaptation are discussed. PMID:25254109

  15. A particle swarm pattern search method for bound constrained global optimization

    E-print Network

    Vicente, Luís Nunes

    stationarity mentioned before. The particle swarm optimization algorithm was firstly proposed in [11, 24A particle swarm pattern search method for bound constrained global optimization A. Ismael F. Vaz, pattern search, particle swarm, derivative free optimization, global optimization, bound constrained

  16. Fruitful visual search: Inhibition of return in a virtual foraging task

    Microsoft Academic Search

    Laura E. Thomas; Michael S. Ambinder; Brendon Hsieh; Brian Levinthal; James A. Crowell; David E. Irwin; Arthur F. Kramer; Alejandro Lleras; Daniel J. Simons; Ranxiao Frances Wang

    2006-01-01

    Inhibition of return (IOR) has long been viewed as a foraging facilitator in visual search. We investigated the contribution\\u000a of IOR in a task that approximates natural foraging more closely than typical visual search tasks. Participants in a fully\\u000a immersive virtual reality environment manually searched an array of leaves for a hidden piece of fruit, using a wand to select

  17. Transformation of an uncertain video search pipeline to a sketch-based visual analytics loop.

    PubMed

    Legg, Philip A; Chung, David H S; Parry, Matthew L; Bown, Rhodri; Jones, Mark W; Griffiths, Iwan W; Chen, Min

    2013-12-01

    Traditional sketch-based image or video search systems rely on machine learning concepts as their core technology. However, in many applications, machine learning alone is impractical since videos may not be semantically annotated sufficiently, there may be a lack of suitable training data, and the search requirements of the user may frequently change for different tasks. In this work, we develop a visual analytics systems that overcomes the shortcomings of the traditional approach. We make use of a sketch-based interface to enable users to specify search requirement in a flexible manner without depending on semantic annotation. We employ active machine learning to train different analytical models for different types of search requirements. We use visualization to facilitate knowledge discovery at the different stages of visual analytics. This includes visualizing the parameter space of the trained model, visualizing the search space to support interactive browsing, visualizing candidature search results to support rapid interaction for active learning while minimizing watching videos, and visualizing aggregated information of the search results. We demonstrate the system for searching spatiotemporal attributes from sports video to identify key instances of the team and player performance. PMID:24051777

  18. Enhanced Visual Search in Infancy Predicts Emerging Autism Symptoms

    PubMed Central

    Gliga, Teodora; Bedford, Rachael; Charman, Tony; Johnson, Mark H.; Baron-Cohen, Simon; Bolton, Patrick; Cheung, Celeste; Davies, Kim; Liew, Michelle; Fernandes, Janice; Gammer, Issy; Maris, Helen; Salomone, Erica; Pasco, Greg; Pickles, Andrew; Ribeiro, Helena; Tucker, Leslie

    2015-01-01

    Summary In addition to core symptoms, i.e., social interaction and communication difficulties and restricted and repetitive behaviors, autism is also characterized by aspects of superior perception [1]. One well-replicated finding is that of superior performance in visual search tasks, in which participants have to indicate the presence of an odd-one-out element among a number of foils [2–5]. Whether these aspects of superior perception contribute to the emergence of core autism symptoms remains debated [4, 6]. Perceptual and social interaction atypicalities could reflect co-expressed but biologically independent pathologies, as suggested by a “fractionable” phenotype model of autism [7]. A developmental test of this hypothesis is now made possible by longitudinal cohorts of infants at high risk, such as of younger siblings of children with autism spectrum disorder (ASD). Around 20% of younger siblings are diagnosed with autism themselves [8], and up to another 30% manifest elevated levels of autism symptoms [9]. We used eye tracking to measure spontaneous orienting to letter targets (O, S, V, and +) presented among distractors (the letter X; Figure 1). At 9 and 15 months, emerging autism symptoms were assessed using the Autism Observation Scale for Infants (AOSI; [10]), and at 2 years of age, they were assessed using the Autism Diagnostic Observation Schedule (ADOS; [11]). Enhanced visual search performance at 9 months predicted a higher level of autism symptoms at 15 months and at 2 years. Infant perceptual atypicalities are thus intrinsically linked to the emerging autism phenotype. PMID:26073135

  19. Conversation Clock: Visualizing audio patterns in co-located groups

    Microsoft Academic Search

    Tony Bergstrom; Karrie Karahalios

    2007-01-01

    Aural conversation is ephemeral by nature. The interaction history of conversation fades as the present moment demands the attention of participants. In this paper, we explore the nature of group interaction by augmenting aural conversation with a persistent visualization of audio input. This visualization, Conversation Clock, displays individual contribution via audio input and provides a corresponding social mirror over the

  20. Parafoveal Retinal Vascular Response to Pattern Visual Stimulation Assessed with OCT Angiography

    E-print Network

    Wei, Eric

    We used optical coherence tomography (OCT) angiography with a high-speed swept-source OCT system to investigate retinal blood flow changes induced by visual stimulation with a reversing checkerboard pattern. The split-spectrum ...

  1. Pattern Visual Evoked Cortical Potentials in Patients With Toxic Optic Neuropathy Caused by Toluene Abuse

    Microsoft Academic Search

    Masahiro Kiyokawa; Atsushi Mizota; Michihiko Takasoh; Emiko Adachi-Usami

    1999-01-01

    Purpose: Electrophysiological evaluation of the visual function of patients with toxic neuropathy caused by toluene abuse.Methods: Fifteen patients (mean age 25.6 years, eight men and seven women) were diagnosed with bilateral optic neuropathy. Pattern visual evoked cortical potentials (PVECPs) and clinical symptoms were investigated.Results: Visual acuities at the initial visit were less than 0.1 in 5 cases and 0.1–1.0 in

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

  3. 'Meaningful' patterns in visual noise: effects of lateral stimulation and the observer's belief in ESP.

    PubMed

    Brugger, P; Regard, M; Landis, T; Cook, N; Krebs, D; Niederberger, J

    1993-01-01

    Visual noise subjectively contains more meaningful patterns (1) when tachistoscopically presented to the left visual field, and (2) for persons who believe in extrasensory perception (ESP). These results indicate a possible right hemisphere mediation of delusional perception and suggest some delusional component in the belief in ESP. PMID:8190845

  4. How visual edge features influence cuttlefish camouflage patterning Chuan-Chin Chiao a,b,

    E-print Network

    California at Irvine, University of

    How visual edge features influence cuttlefish camouflage patterning Chuan-Chin Chiao a Sepia officinalis a b s t r a c t Rapid adaptive camouflage is the primary defense of soft Cephalopod camouflage is the fastest changing and most versa- tile in the animal kingdom. These visually

  5. Disruptive Body Patterning of Cuttlefish (Sepia officinalis) Requires Visual Information Regarding

    E-print Network

    Hanlon, Roger T.

    Disruptive Body Patterning of Cuttlefish (Sepia officinalis) Requires Visual Information Regarding of Sussex, Brighton, UK Cuttlefish (Sepia officinalis Linnaeus, 1758) on mixed light and dark gravel show of natural substrates that cuttlefish cue on visually are largely unknown. Therefore, we aimed to identify

  6. Prediction of shot success for basketball free throws: visual search strategy.

    PubMed

    Uchida, Yusuke; Mizuguchi, Nobuaki; Honda, Masaaki; Kanosue, Kazuyuki

    2014-01-01

    In ball games, players have to pay close attention to visual information in order to predict the movements of both the opponents and the ball. Previous studies have indicated that players primarily utilise cues concerning the ball and opponents' body motion. The information acquired must be effective for observing players to select the subsequent action. The present study evaluated the effects of changes in the video replay speed on the spatial visual search strategy and ability to predict free throw success. We compared eye movements made while observing a basketball free throw by novices and experienced basketball players. Correct response rates were close to chance (50%) at all video speeds for the novices. The correct response rate of experienced players was significantly above chance (and significantly above that of the novices) at the normal speed, but was not different from chance at both slow and fast speeds. Experienced players gazed more on the lower part of the player's body when viewing a normal speed video than the novices. The players likely detected critical visual information to predict shot success by properly moving their gaze according to the shooter's movements. This pattern did not change when the video speed was decreased, but changed when it was increased. These findings suggest that temporal information is important for predicting action outcomes and that such outcomes are sensitive to video speed. PMID:24319995

  7. Visual Search Is Postponed during the Attentional Blink until the System Is Suitably Reconfigured

    ERIC Educational Resources Information Center

    Ghorashi, S. M. Shahab; Smilek, Daniel; Di Lollo, Vincent

    2007-01-01

    J. S. Joseph, M. M. Chun, and K. Nakayama (1997) found that pop-out visual search was impaired as a function of intertarget lag in an attentional blink (AB) paradigm in which the 1st target was a letter and the 2nd target was a search display. In 4 experiments, the present authors tested the implication that search efficiency should be similarly…

  8. The effects of visual search efficiency on object-based attention.

    PubMed

    Greenberg, Adam S; Rosen, Maya; Cutrone, Elizabeth; Behrmann, Marlene

    2015-07-01

    The attentional prioritization hypothesis of object-based attention (Shomstein & Yantis in Perception & Psychophysics, 64, 41-51, 2002) suggests a two-stage selection process comprising an automatic spatial gradient and flexible strategic (prioritization) selection. The combined attentional priorities of these two stages of object-based selection determine the order in which participants will search the display for the presence of a target. The strategic process has often been likened to a prioritized visual search. By modifying the double-rectangle cueing paradigm (Egly, Driver, & Rafal in Journal of Experimental Psychology: General, 123, 161-177, 1994) and placing it in the context of a larger-scale visual search, we examined how the prioritization search is affected by search efficiency. By probing both targets located on the cued object and targets external to the cued object, we found that the attentional priority surrounding a selected object is strongly modulated by search mode. However, the ordering of the prioritization search is unaffected by search mode. The data also provide evidence that standard spatial visual search and object-based prioritization search may rely on distinct mechanisms. These results provide insight into the interactions between the mode of visual search and object-based selection, and help define the modulatory consequences of search efficiency for object-based attention. PMID:25832192

  9. Aging and visual search: Automatic and controlled attentional bias to threat faces

    Microsoft Academic Search

    Sowon Hahn; Curt Carlson; Shawn Singer; Scott D. Gronlund

    2006-01-01

    Using a visual search paradigm, we investigated how age affected attentional bias to emotional facial expressions. In Experiments 1 and 2, participants searched for a discrepant facial expression in a matrix of otherwise homogeneous faces. Both younger and older adults showed a more effective search when the discrepant face was angry rather than happy or neutral. However, when the angry

  10. Modeling the design of visual search tasks in human-computer interaction

    Microsoft Academic Search

    Baili Liu

    2000-01-01

    Previous studies in identifying factors related to search efficiency resulted in empirical models that are hard to apply. In order to overcome the limitations inherent in descriptive empirical methods, a quantitative model of visual search, the Guided Search (GS) model, which has been validated in many perceptual tasks, was extended to Human-Computer Interaction (HCI) settings. By testing the validity of

  11. Visual Search Is Postponed During the Attentional Blink Until the System Is Suitably Reconfigured

    Microsoft Academic Search

    S. M. Shahab Ghorashi; Daniel Smilek; Vincent Di Lollo

    2007-01-01

    J. S. Joseph, M. M. Chun, and K. Nakayama (1997) found that pop-out visual search was impaired as a function of intertarget lag in an attentional blink (AB) paradigm in which the 1st target was a letter and the 2nd target was a search display. In 4 experiments, the present authors tested the implication that search efficiency should be similarly

  12. Searching for the right word: Hybrid visual and memory search for words.

    PubMed

    Boettcher, Sage E P; Wolfe, Jeremy M

    2015-05-01

    In "hybrid search" (Wolfe Psychological Science, 23(7), 698-703, 2012), observers search through visual space for any of multiple targets held in memory. With photorealistic objects as the stimuli, response times (RTs) increase linearly with the visual set size and logarithmically with the memory set size, even when over 100 items are committed to memory. It is well-established that pictures of objects are particularly easy to memorize (Brady, Konkle, Alvarez, & Oliva Proceedings of the National Academy of Sciences, 105, 14325-14329, 2008). Would hybrid-search performance be similar if the targets were words or phrases, in which word order can be important, so that the processes of memorization might be different? In Experiment 1, observers memorized 2, 4, 8, or 16 words in four different blocks. After passing a memory test, confirming their memorization of the list, the observers searched for these words in visual displays containing two to 16 words. Replicating Wolfe (Psychological Science, 23(7), 698-703, 2012), the RTs increased linearly with the visual set size and logarithmically with the length of the word list. The word lists of Experiment 1 were random. In Experiment 2, words were drawn from phrases that observers reported knowing by heart (e.g., "London Bridge is falling down"). Observers were asked to provide four phrases, ranging in length from two words to no less than 20 words (range 21-86). All words longer than two characters from the phrase, constituted the target list. Distractor words were matched for length and frequency. Even with these strongly ordered lists, the results again replicated the curvilinear function of memory set size seen in hybrid search. One might expect to find serial position effects, perhaps reducing the RTs for the first (primacy) and/or the last (recency) members of a list (Atkinson & Shiffrin, 1968; Murdock Journal of Experimental Psychology, 64, 482-488, 1962). Surprisingly, we showed no reliable effects of word order. Thus, in "London Bridge is falling down," "London" and "down" were found no faster than "falling." PMID:25788035

  13. Disruptive coloration in cuttlefish: a visual perception mechanism that regulates ontogenetic adjustment of skin patterning.

    PubMed

    Barbosa, Alexandra; Mäthger, Lydia M; Chubb, Charles; Florio, Christopher; Chiao, Chuan-Chin; Hanlon, Roger T

    2007-04-01

    Among the changeable camouflage patterns of cuttlefish, disruptive patterning is shown in response to certain features of light objects in the visual background. However, whether animals show disruptive patterns is dependent not only on object size but also on their body size. Here, we tested whether cuttlefish (Sepia officinalis) are able to match their disruptive body patterning with increasing size of background objects as they grow from hatchling to adult size (0.7 to 19.6 cm mantle length; factor of 28). Specifically, do cuttlefish have a single ;visual sampling rule' that scales accurately during ontogeny? For each of seven size classes of cuttlefish, we created black and white checkerboards whose check sizes corresponded to 4, 12, 40, 120, 400 and 1200% of the area of the cuttlefish's White square, which is a neurophysiologically controlled component of the skin. Disruptive body patterns were evoked when, regardless of animal size, the check size measured either 40 or 120% of the area of the cuttlefish's White square, thus demonstrating a remarkable ontogenetic conformity to a single visual sampling rule. Cuttlefish have no known visual feedback loop with which to adjust their skin patterns. Since the area of a cuttlefish's White square skin component is a function of body size, our results indicate that cuttlefish are solving a visual scaling problem of camouflage presumably without visual confirmation of the size of their own skin component. PMID:17371913

  14. Effect of pattern complexity on the visual span for Chinese and alphabet characters.

    PubMed

    Wang, Hui; He, Xuanzi; Legge, Gordon E

    2014-01-01

    The visual span for reading is the number of letters that can be recognized without moving the eyes and is hypothesized to impose a sensory limitation on reading speed. Factors affecting the size of the visual span have been studied using alphabet letters. There may be common constraints applying to recognition of other scripts. The aim of this study was to extend the concept of the visual span to Chinese characters and to examine the effect of the greater complexity of these characters. We measured visual spans for Chinese characters and alphabet letters in the central vision of bilingual subjects. Perimetric complexity was used as a metric to quantify the pattern complexity of binary character images. The visual span tests were conducted with four sets of stimuli differing in complexity--lowercase alphabet letters and three groups of Chinese characters. We found that the size of visual spans decreased with increasing complexity, ranging from 10.5 characters for alphabet letters to 4.5 characters for the most complex Chinese characters studied. A decomposition analysis revealed that crowding was the dominant factor limiting the size of the visual span, and the amount of crowding increased with complexity. Errors in the spatial arrangement of characters (mislocations) had a secondary effect. We conclude that pattern complexity has a major effect on the size of the visual span, mediated in large part by crowding. Measuring the visual span for Chinese characters is likely to have high relevance to understanding visual constraints on Chinese reading performance. PMID:24993020

  15. Effect of pattern complexity on the visual span for Chinese and alphabet characters

    PubMed Central

    Wang, Hui; He, Xuanzi; Legge, Gordon E.

    2014-01-01

    The visual span for reading is the number of letters that can be recognized without moving the eyes and is hypothesized to impose a sensory limitation on reading speed. Factors affecting the size of the visual span have been studied using alphabet letters. There may be common constraints applying to recognition of other scripts. The aim of this study was to extend the concept of the visual span to Chinese characters and to examine the effect of the greater complexity of these characters. We measured visual spans for Chinese characters and alphabet letters in the central vision of bilingual subjects. Perimetric complexity was used as a metric to quantify the pattern complexity of binary character images. The visual span tests were conducted with four sets of stimuli differing in complexity—lowercase alphabet letters and three groups of Chinese characters. We found that the size of visual spans decreased with increasing complexity, ranging from 10.5 characters for alphabet letters to 4.5 characters for the most complex Chinese characters studied. A decomposition analysis revealed that crowding was the dominant factor limiting the size of the visual span, and the amount of crowding increased with complexity. Errors in the spatial arrangement of characters (mislocations) had a secondary effect. We conclude that pattern complexity has a major effect on the size of the visual span, mediated in large part by crowding. Measuring the visual span for Chinese characters is likely to have high relevance to understanding visual constraints on Chinese reading performance. PMID:24993020

  16. Finding an emotional face in a crowd: emotional and perceptual stimulus factors influence visual search efficiency.

    PubMed

    Lundqvist, Daniel; Bruce, Neil; Öhman, Arne

    2015-01-01

    In this article, we examine how emotional and perceptual stimulus factors influence visual search efficiency. In an initial task, we run a visual search task, using a large number of target/distractor emotion combinations. In two subsequent tasks, we then assess measures of perceptual (rated and computational distances) and emotional (rated valence, arousal and potency) stimulus properties. In a series of regression analyses, we then explore the degree to which target salience (the size of target/distractor dissimilarities) on these emotional and perceptual measures predict the outcome on search efficiency measures (response times and accuracy) from the visual search task. The results show that both emotional and perceptual stimulus salience contribute to visual search efficiency. The results show that among the emotional measures, salience on arousal measures was more influential than valence salience. The importance of the arousal factor may be a contributing factor to contradictory history of results within this field. PMID:24933527

  17. Visual Search and Line Bisection in Hemianopia: Computational Modelling of Cortical Compensatory Mechanisms and Comparison with Hemineglect

    PubMed Central

    Lanyon, Linda J.; Barton, Jason J. S.

    2013-01-01

    Hemianopia patients have lost vision from the contralateral hemifield, but make behavioural adjustments to compensate for this field loss. As a result, their visual performance and behaviour contrast with those of hemineglect patients who fail to attend to objects contralateral to their lesion. These conditions differ in their ocular fixations and perceptual judgments. During visual search, hemianopic patients make more fixations in contralesional space while hemineglect patients make fewer. During line bisection, hemianopic patients fixate the contralesional line segment more and make a small contralesional bisection error, while hemineglect patients make few contralesional fixations and a larger ipsilesional bisection error. Hence, there is an attentional failure for contralesional space in hemineglect but a compensatory adaptation to attend more to the blind side in hemianopia. A challenge for models of visual attentional processes is to show how compensation is achieved in hemianopia, and why such processes are hindered or inaccessible in hemineglect. We used a neurophysiology-derived computational model to examine possible cortical compensatory processes in simulated hemianopia from a V1 lesion and compared results with those obtained with the same processes under conditions of simulated hemineglect from a parietal lesion. A spatial compensatory bias to increase attention contralesionally replicated hemianopic scanning patterns during visual search but not during line bisection. To reproduce the latter required a second process, an extrastriate lateral connectivity facilitating form completion into the blind field: this allowed accurate placement of fixations on contralesional stimuli and reproduced fixation patterns and the contralesional bisection error of hemianopia. Neither of these two cortical compensatory processes was effective in ameliorating the ipsilesional bias in the hemineglect model. Our results replicate normal and pathological patterns of visual scanning, line bisection, and differences between hemianopia and hemineglect, and may explain why compensatory processes that counter the effects of hemianopia are ineffective in hemineglect. PMID:23390506

  18. Learning From Data: Recognizing Glaucomatous Defect Patterns and Detecting Progression From Visual Field Measurements

    PubMed Central

    Yousefi, Siamak; Goldbaum, Michael H.; Balasubramanian, Madhusudhanan; Medeiros, Felipe A.; Zangwill, Linda M.; Liebmann, Jeffrey M.; Girkin, Christopher A.; Weinreb, Robert N.

    2014-01-01

    A hierarchical approach to learn from visual field data was adopted to identify glaucomatous visual field defect patterns and to detect glaucomatous progression. The analysis pipeline included three stages, namely, clustering, glaucoma boundary limit detection, and glaucoma progression detection testing. First, cross-sectional visual field tests collected from each subject were clustered using a mixture of Gaussians and model parameters were estimated using expectation maximization. The visual field clusters were further estimated to recognize glaucomatous visual field defect patterns by decomposing each cluster into several axes. The glaucoma visual field defect patterns along each axis then were identified. To derive a definition of progression, the longitudinal visual fields of stable glaucoma eyes on the abnormal cluster axes were projected and the slope was approximated using linear regression (LR) to determine the confidence limit of each axis. For glaucoma progression detection, the longitudinal visual fields of each eye on the abnormal cluster axes were projected and the slope was approximated by LR. Progression was assigned if the progression rate was greater than the boundary limit of the stable eyes; otherwise, stability was assumed. The proposed method was compared to a recently developed progression detection method and to clinically available glaucoma progression detection software. The clinical accuracy of the proposed pipeline was as good as or better than the currently available methods. PMID:24710816

  19. Learning from data: recognizing glaucomatous defect patterns and detecting progression from visual field measurements.

    PubMed

    Yousefi, Siamak; Goldbaum, Michael H; Balasubramanian, Madhusudhanan; Medeiros, Felipe A; Zangwill, Linda M; Liebmann, Jeffrey M; Girkin, Christopher A; Weinreb, Robert N; Bowd, Christopher

    2014-07-01

    A hierarchical approach to learn from visual field data was adopted to identify glaucomatous visual field defect patterns and to detect glaucomatous progression. The analysis pipeline included three stages, namely, clustering, glaucoma boundary limit detection, and glaucoma progression detection testing. First, cross-sectional visual field tests collected from each subject were clustered using a mixture of Gaussians and model parameters were estimated using expectation maximization. The visual field clusters were further estimated to recognize glaucomatous visual field defect patterns by decomposing each cluster into several axes. The glaucoma visual field defect patterns along each axis then were identified. To derive a definition of progression, the longitudinal visual fields of stable glaucoma eyes on the abnormal cluster axes were projected and the slope was approximated using linear regression (LR) to determine the confidence limit of each axis. For glaucoma progression detection, the longitudinal visual fields of each eye on the abnormal cluster axes were projected and the slope was approximated by LR. Progression was assigned if the progression rate was greater than the boundary limit of the stable eyes; otherwise, stability was assumed. The proposed method was compared to a recently developed progression detection method and to clinically available glaucoma progression detection software. The clinical accuracy of the proposed pipeline was as good as or better than the currently available methods. PMID:24710816

  20. Camouflage by Edge Enhancement in Animal Coloration Patterns and Its Implications for Visual Mechanisms

    Microsoft Academic Search

    D. Osorio; M. V. Srinivasan

    1991-01-01

    Animal camouflage patterns may exploit, and thus give an insight into, visual processing mechanisms. In one common type of camouflage the borders of the coloured patterns are enhanced by high contrast lines. This type of camouflage is seen on many frogs and we use it as the basis for speculating about vision in a small, frog-eating snake. It is argued

  1. A Visualization System for Space-Time and Multivariate Patterns (VIS-STAMP)

    E-print Network

    --The research reported here integrates computational, visual, and cartographic methods to develop a geovisual methods), a geographic small multiple display, and a 2-dimensional cartographic color design method of complex patterns and, through a variety of interactions, enables users to focus on specific patterns

  2. Overlapping Matrix Pattern Visualization: a Hypergraph Approach Ruoming Jin Yang Xiang David Fuhry Feodor F. Dragan

    E-print Network

    Jin, Ruoming

    be converted into a bi- nary matrix by considering that each gene is either "on" or "off". The typical patternOverlapping Matrix Pattern Visualization: a Hypergraph Approach Ruoming Jin Yang Xiang David Fuhry of discovered overlapping submatrices of inter- est, how can we order the rows and columns of the data matrix

  3. Production and perception rules underlying visual patterns: effects of symmetry and hierarchy

    PubMed Central

    Westphal-Fitch, Gesche; Huber, Ludwig; Gómez, Juan Carlos; Fitch, W. Tecumseh

    2012-01-01

    Formal language theory has been extended to two-dimensional patterns, but little is known about two-dimensional pattern perception. We first examined spontaneous two-dimensional visual pattern production by humans, gathered using a novel touch screen approach. Both spontaneous creative production and subsequent aesthetic ratings show that humans prefer ordered, symmetrical patterns over random patterns. We then further explored pattern-parsing abilities in different human groups, and compared them with pigeons. We generated visual plane patterns based on rules varying in complexity. All human groups tested, including children and individuals diagnosed with autism spectrum disorder (ASD), were able to detect violations of all production rules tested. Our ASD participants detected pattern violations with the same speed and accuracy as matched controls. Children's ability to detect violations of a relatively complex rotational rule correlated with age, whereas their ability to detect violations of a simple translational rule did not. By contrast, even with extensive training, pigeons were unable to detect orientation-based structural violations, suggesting that, unlike humans, they did not learn the underlying structural rules. Visual two-dimensional patterns offer a promising new formally-grounded way to investigate pattern production and perception in general, widely applicable across species and age groups. PMID:22688636

  4. High or Low Target Prevalence Increases the Dual-Target Cost in Visual Search

    Microsoft Academic Search

    Tamaryn Menneer; Nick Donnelly; Hayward J. Godwin; Kyle R. Cave

    2010-01-01

    Previous studies have demonstrated a dual-target cost in visual search. In the current study, the relationship between search for one and search for two targets was investigated to examine the effects of target prevalence and practice. Color-shape conjunction stimuli were used with response time, accuracy and signal detection measures. Performance was lower in dual-target search compared with the combined performance

  5. The Effects of Age and Exogenous Support on Visual Search Performance

    Microsoft Academic Search

    Paula M. McLaughlin; Susan J. E. Murtha

    2010-01-01

    The authors investigated whether precueing a location attenuated age-related declines in selective attention and intraindividual variability on a visual search task. The cue improved response time on the single-feature search condition for both young and older adults. On the conjoined-feature search condition, only the older adults used the cue to facilitate performance, particularly when it reduced the number of searched

  6. Individual differences in visual search: relationship to autistic traits, discrimination thresholds, and speed of processing.

    PubMed

    Brock, Jon; Xu, Jing Y; Brooks, Kevin R

    2011-01-01

    Enhanced visual search is widely reported in autism. Here we note a similar advantage for university students self-reporting higher levels of autism-like traits. Contrary to prevailing theories of autism, performance was not associated with perceptual-discrimination thresholds for the same stimuli, but was associated with inspection-time threshold--a measure of speed of perceptual processing. Enhanced visual search in autism may, therefore, at least partially be explained by faster speed of processing. PMID:21936301

  7. The influence of action on visual search: behavioral response toward stimuli modifies the selection process

    Microsoft Academic Search

    Daniel R. Buttaccio; Sowon Hahn

    2011-01-01

    In five experiments, we investigated how simple actions (as assessed via a go\\/no-go task) influence visual search. In Experiments 1 and 2, participants responded (go) when a color name (cue) matched a colored shape (prime), and did not respond (no-go) when they\\u000a mismatched. Participants then searched a visual array for a tilted line, either embedded within the prime (valid prime)

  8. Age-Related Preservation of Top-Down Control Over Distraction in Visual Search

    Microsoft Academic Search

    Matthew C. Costello; David J. Madden; Anne M. Shepler; Stephen R. Mitroff; Andrew B. Leber

    2010-01-01

    Visual search studies have demonstrated that older adults can have preserved or even increased top-down control over distraction. However, the results are mixed as to the extent of this age-related preservation. The present experiment assesses group differences in younger and older adults during visual search, with a task featuring two conditions offering varying degrees of top-down control over distraction. After

  9. Search algorithm for pattern match analysis of nucleic acid sequences.

    PubMed Central

    Harr, R; Häggström, M; Gustafsson, P

    1983-01-01

    A new type of search algorithm to find biological information inherited in nucleic acid sequences was developed. The algorithm is of pattern match type and is based on the fact that genetic information often is a function of a predictable statistical occurrence of the four bases within parts of the sequence. The search algorithm compares the known statistical pattern of bases in e.g. a promoter, with an unknown sequence and calculates the statistical significance of the match at all positions in the unknown sequence. The program was tested on 54 published prokaryotic promoters. 44 or 49 could be found with 1 or 4 false answers, respectively. The program was also used on plasmid pBR322. All promoters functioning in an in vitro transcription system were found (tet, anti-tet, p4, bla and ori) except the so called p5 promoter. A search for donor and acceptor sites was performed in a human HLA genomic sequence that contains six introns. Five of the possible six donor and acceptor sites were found. PMID:6344023

  10. Visualization and analysis of 3D gene expression patterns in zebrafish using web services

    NASA Astrophysics Data System (ADS)

    Potikanond, D.; Verbeek, F. J.

    2012-01-01

    The analysis of patterns of gene expression patterns analysis plays an important role in developmental biology and molecular genetics. Visualizing both quantitative and spatio-temporal aspects of gene expression patterns together with referenced anatomical structures of a model-organism in 3D can help identifying how a group of genes are expressed at a certain location at a particular developmental stage of an organism. In this paper, we present an approach to provide an online visualization of gene expression data in zebrafish (Danio rerio) within 3D reconstruction model of zebrafish in different developmental stages. We developed web services that provide programmable access to the 3D reconstruction data and spatial-temporal gene expression data maintained in our local repositories. To demonstrate this work, we develop a web application that uses these web services to retrieve data from our local information systems. The web application also retrieve relevant analysis of microarray gene expression data from an external community resource; i.e. the ArrayExpress Atlas. All the relevant gene expression patterns data are subsequently integrated with the reconstruction data of the zebrafish atlas using ontology based mapping. The resulting visualization provides quantitative and spatial information on patterns of gene expression in a 3D graphical representation of the zebrafish atlas in a certain developmental stage. To deliver the visualization to the user, we developed a Java based 3D viewer client that can be integrated in a web interface allowing the user to visualize the integrated information over the Internet.

  11. Different predictors of multiple-target search accuracy between nonprofessional and professional visual searchers.

    PubMed

    Biggs, Adam T; Mitroff, Stephen R

    2014-01-01

    Visual search, locating target items among distractors, underlies daily activities ranging from critical tasks (e.g., looking for dangerous objects during security screening) to commonplace ones (e.g., finding your friends in a crowded bar). Both professional and nonprofessional individuals conduct visual searches, and the present investigation is aimed at understanding how they perform similarly and differently. We administered a multiple-target visual search task to both professional (airport security officers) and nonprofessional participants (members of the Duke University community) to determine how search abilities differ between these populations and what factors might predict accuracy. There were minimal overall accuracy differences, although the professionals were generally slower to respond. However, the factors that predicted accuracy varied drastically between groups; variability in search consistency-how similarly an individual searched from trial to trial in terms of speed-best explained accuracy for professional searchers (more consistent professionals were more accurate), whereas search speed-how long an individual took to complete a search when no targets were present-best explained accuracy for nonprofessional searchers (slower nonprofessionals were more accurate). These findings suggest that professional searchers may utilize different search strategies from those of nonprofessionals, and that search consistency, in particular, may provide a valuable tool for enhancing professional search accuracy. PMID:24266390

  12. The effects of task difficulty on visual search strategy in virtual 3D displays

    PubMed Central

    Pomplun, Marc; Garaas, Tyler W.; Carrasco, Marisa

    2013-01-01

    Analyzing the factors that determine our choice of visual search strategy may shed light on visual behavior in everyday situations. Previous results suggest that increasing task difficulty leads to more systematic search paths. Here we analyze observers' eye movements in an “easy” conjunction search task and a “difficult” shape search task to study visual search strategies in stereoscopic search displays with virtual depth induced by binocular disparity. Standard eye-movement variables, such as fixation duration and initial saccade latency, as well as new measures proposed here, such as saccadic step size, relative saccadic selectivity, and x?y target distance, revealed systematic effects on search dynamics in the horizontal-vertical plane throughout the search process. We found that in the “easy” task, observers start with the processing of display items in the display center immediately after stimulus onset and subsequently move their gaze outwards, guided by extrafoveally perceived stimulus color. In contrast, the “difficult” task induced an initial gaze shift to the upper-left display corner, followed by a systematic left-right and top-down search process. The only consistent depth effect was a trend of initial saccades in the easy task with smallest displays to the items closest to the observer. The results demonstrate the utility of eye-movement analysis for understanding search strategies and provide a first step toward studying search strategies in actual 3D scenarios. PMID:23986539

  13. Visual cluster analysis and pattern recognition template and methods

    DOEpatents

    Osbourn, G.C.; Martinez, R.F.

    1999-05-04

    A method of clustering using a novel template to define a region of influence is disclosed. Using neighboring approximation methods, computation times can be significantly reduced. The template and method are applicable and improve pattern recognition techniques. 30 figs.

  14. The Effects of Presentation Method and Information Density on Visual Search Ability and Working Memory Load

    ERIC Educational Resources Information Center

    Chang, Ting-Wen; Kinshuk; Chen, Nian-Shing; Yu, Pao-Ta

    2012-01-01

    This study investigates the effects of successive and simultaneous information presentation methods on learner's visual search ability and working memory load for different information densities. Since the processing of information in the brain depends on the capacity of visual short-term memory (VSTM), the limited information processing capacity…

  15. The Role of Target-Distractor Relationships in Guiding Attention and the Eyes in Visual Search

    ERIC Educational Resources Information Center

    Becker, Stefanie I.

    2010-01-01

    Current models of visual search assume that visual attention can be guided by tuning attention toward specific feature values (e.g., particular size, color) or by inhibiting the features of the irrelevant nontargets. The present study demonstrates that attention and eye movements can also be guided by a relational specification of how the target…

  16. Learning by Selection: Visual Search and Object Perception in Young Infants

    ERIC Educational Resources Information Center

    Amso, Dima; Johnson, Scott P.

    2006-01-01

    The authors examined how visual selection mechanisms may relate to developing cognitive functions in infancy. Twenty-two 3-month-old infants were tested in 2 tasks on the same day: perceptual completion and visual search. In the perceptual completion task, infants were habituated to a partly occluded moving rod and subsequently presented with …

  17. Detection of Emotional Faces: Salient Physical Features Guide Effective Visual Search

    ERIC Educational Resources Information Center

    Calvo, Manuel G.; Nummenmaa, Lauri

    2008-01-01

    In this study, the authors investigated how salient visual features capture attention and facilitate detection of emotional facial expressions. In a visual search task, a target emotional face (happy, disgusted, fearful, angry, sad, or surprised) was presented in an array of neutral faces. Faster detection of happy and, to a lesser extent,…

  18. Responses of Neurons in Macaque Area V4 During Memory-guided Visual Search

    Microsoft Academic Search

    Leonardo Chelazzi; Earl K. Miller; John Duncan; Robert Desimone

    2001-01-01

    In a typical scene with many different objects, attentional mechan- isms are needed to select relevant objects for visual processing and control over behavior. To test the role of area V4 in the selection of objects based on non-spatial features, we recorded from V4 neurons in the monkey, using a visual search paradigm. A cue stimulus was presented at the

  19. Evaluating variable resolution displays with visual search: task performance and eye movements

    Microsoft Academic Search

    Derrick Parkhurst; Eugenio Culurciello; Ernst Niebur

    2000-01-01

    Gaze-contingent variable resolution display techniques allocate computational resources for image generation preferentially to the area around the center of gaze where visual sensitivity to detail is the greatest. Although these techniques are computationally efficient, their behavioral consequences with realistic tasks and materials are not well understood. The behavior of human observers performing visual search of natural scenes using gaze-contingent variable

  20. Adaptive but non-optimal visual search behavior with highlighted displays q

    E-print Network

    Byrne, Mike

    strategies by probability-matching to their visual environment. An ACT-R [Anderson, J. R., Bothell, D., Byrne: ACT-R; Learning; Probabilistic environment; Visual search 1. Introduction Certain properties of our had been used to evaluate fit of the micro-level ACT-R model. The authors accept full responsibility

  1. Hand Movement Deviations in a Visual Search Task with Cross Modal Cuing

    ERIC Educational Resources Information Center

    Aslan, Asli; Aslan, Hurol

    2007-01-01

    The purpose of this study is to demonstrate the cross-modal effects of an auditory organization on a visual search task and to investigate the influence of the level of detail in instructions describing or hinting at the associations between auditory stimuli and the possible locations of a visual target. In addition to measuring the participants'…

  2. A Pattern Recognition Feature Optimization Tool Using the Visual Empirical Region of Influence Algorithm

    SciTech Connect

    MARTINEZ, RUBEL F.

    2002-06-01

    This document is the second in a series that describe graphical user interface tools developed to control the Visual Empirical Region of Influence (VERI) algorithm. In this paper we describe a user interface designed to optimize the VERI algorithm results. The optimization mode uses a brute force method of searching through the combinations of features in a data set for features that produce the best pattern recognition results. With a small number of features in a data set an exact solution can be determined. However, the number of possible combinations increases exponentially with the number of features and an alternate means of finding a solution must be found. We developed and implemented a technique for finding solutions in data sets with both small and large numbers of features. This document illustrates step-by-step examples of how to use the interface and how to interpret the results. It is written in two parts, part I deals with using the interface to find the best combination from all possible sets of features, part II describes how to use the tool to find a good solution in data sets with a large number of features. The VERI Optimization Interface Tool was written using the Tcl/Tk Graphical User Interface (GUI) programming language, version 8.1. Although the Tcl/Tk packages are designed to run on multiple computer platforms, we have concentrated our efforts to develop a user interface for the ubiquitous DOS environment. The VERI algorithms are compiled, executable programs. The optimization interface executes the VERI algorithm in Leave-One-Out mode using the Euclidean metric. For a thorough description of the type of data analysis we perform, and for a general Pattern Recognition tutorial, refer to our website at: http://www.sandia.gov/imrl/XVisionScience/Xusers.htm.

  3. Performance in a Visual Search Task Uniquely Predicts Reading Abilities in Third-Grade Hong Kong Chinese Children

    ERIC Educational Resources Information Center

    Liu, Duo; Chen, Xi; Chung, Kevin K. H.

    2015-01-01

    This study examined the relation between the performance in a visual search task and reading ability in 92 third-grade Hong Kong Chinese children. The visual search task, which is considered a measure of visual-spatial attention, accounted for unique variance in Chinese character reading after controlling for age, nonverbal intelligence,…

  4. Crowding by a single bar: probing pattern recognition mechanisms in the visual periphery.

    PubMed

    Põder, Endel

    2014-01-01

    Whereas visual crowding does not greatly affect the detection of the presence of simple visual features, it heavily inhibits combining them into recognizable objects. Still, crowding effects have rarely been directly related to general pattern recognition mechanisms. In this study, pattern recognition mechanisms in visual periphery were probed using a single crowding feature. Observers had to identify the orientation of a rotated T presented briefly in a peripheral location. Adjacent to the target, a single bar was presented. The bar was either horizontal or vertical and located in a random direction from the target. It appears that such a crowding bar has very strong and regular effects on the identification of the target orientation. The observer's responses are determined by approximate relative positions of basic visual features; exact image-based similarity to the target is not important. A version of the "standard model" of object recognition with second-order features explains the main regularities of the data. PMID:25378369

  5. Generalized pattern search algorithms with adaptive precision function evaluations

    SciTech Connect

    Polak, Elijah; Wetter, Michael

    2003-05-14

    In the literature on generalized pattern search algorithms, convergence to a stationary point of a once continuously differentiable cost function is established under the assumption that the cost function can be evaluated exactly. However, there is a large class of engineering problems where the numerical evaluation of the cost function involves the solution of systems of differential algebraic equations. Since the termination criteria of the numerical solvers often depend on the design parameters, computer code for solving these systems usually defines a numerical approximation to the cost function that is discontinuous with respect to the design parameters. Standard generalized pattern search algorithms have been applied heuristically to such problems, but no convergence properties have been stated. In this paper we extend a class of generalized pattern search algorithms to a form that uses adaptive precision approximations to the cost function. These numerical approximations need not define a continuous function. Our algorithms can be used for solving linearly constrained problems with cost functions that are at least locally Lipschitz continuous. Assuming that the cost function is smooth, we prove that our algorithms converge to a stationary point. Under the weaker assumption that the cost function is only locally Lipschitz continuous, we show that our algorithms converge to points at which the Clarke generalized directional derivatives are nonnegative in predefined directions. An important feature of our adaptive precision scheme is the use of coarse approximations in the early iterations, with the approximation precision controlled by a test. Such an approach leads to substantial time savings in minimizing computationally expensive functions.

  6. Performance of visual search tasks from various types of contour information.

    PubMed

    Itan, Liron; Yitzhaky, Yitzhak

    2013-03-01

    A recently proposed visual aid for patients with a restricted visual field (tunnel vision) combines a see-through head-mounted display and a simultaneous minified contour view of the wide-field image of the environment. Such a widening of the effective visual field is helpful for tasks, such as visual search, mobility, and orientation. The sufficiency of image contours for performing everyday visual tasks is of major importance for this application, as well as for other applications, and for basic understanding of human vision. This research aims is to examine and compare the use of different types of automatically created contours, and contour representations, for practical everyday visual operations using commonly observed images. The visual operations include visual searching for items, such as cutlery, housewares, etc. Considering different recognition levels, identification of an object is distinguished from mere detection (when the object is not necessarily identified). Some nonconventional visual-based contour representations were developed for this purpose. Experiments were performed with normal-vision subjects by superposing contours of the wide field of the scene over a narrow field (see-through) background. From the results, it appears that about 85% success is obtained for searched object identification when the best contour versions are employed. Pilot experiments with video simulations are reported at the end of the paper. PMID:23456115

  7. Little correlation of the pattern electroretinogram (PERG) and visual field measures in early glaucoma

    Microsoft Academic Search

    Michael Bach; Frauke Sulimma; Jürgen Gerling

    1997-01-01

    Pattern-electroretinograms (PERG) to checkerboard reversal at 16\\/s. 0.8° and 15° check size and visual fields (Octopus G1)\\u000a were retrospectively analyzed in 40 eyes of 30 patients with early glaucoma. The mean visual field defect was calculated separately\\u000a for the central 26°×34° covered by the PERG stimulus (MDc) and the more peripheral area (MDp) surrounding the stimulus. Deeper\\u000a field loss was

  8. Little correlation of the pattern electroretinogram (PERG) and visual field measures in early glaucoma

    Microsoft Academic Search

    MICHAEL BACH; FRAUKE SULIMMA; URGEN GERLING

    1998-01-01

    Pattern-electroretinograms (PERG) to checkerboard reversal at 16\\/s. 0.8 and 15 check size and visual fields (Octopus G1) were retrospectively analyzed in 40 eyes of 30 patients with early glaucoma. The mean visual field defect was calculated separately for the central 26 34 covered by the PERG stimulus (MDc) and the more peripheral area (MDp) surrounding the stimulus. Deeper field loss

  9. Use of a twin dataset to identify AMD-related visual patterns controlled by genetic factors

    NASA Astrophysics Data System (ADS)

    Quellec, Gwénolé; Abràmoff, Michael D.; Russell, Stephen R.

    2010-03-01

    The mapping of genotype to the phenotype of age-related macular degeneration (AMD) is expected to improve the diagnosis and treatment of the disease in a near future. In this study, we focused on the first step to discover this mapping: we identified visual patterns related to AMD which seem to be controlled by genetic factors, without explicitly relating them to the genes. For this purpose, we used a dataset of eye fundus photographs from 74 twin pairs, either monozygotic twins, who have the same genotype, or dizygotic twins, whose genes responsible for AMD are less likely to be identical. If we are able to differentiate monozygotic twins from dizygotic twins, based on a given visual pattern, then this pattern is likely to be controlled by genetic factors. The main visible consequence of AMD is the apparition of drusen between the retinal pigment epithelium and Bruch's membrane. We developed two automated drusen detectors based on the wavelet transform: a shape-based detector for hard drusen, and a texture- and color- based detector for soft drusen. Forty visual features were evaluated at the location of the automatically detected drusen. These features characterize the texture, the shape, the color, the spatial distribution, or the amount of drusen. A distance measure between twin pairs was defined for each visual feature; a smaller distance should be measured between monozygotic twins for visual features controlled by genetic factors. The predictions of several visual features (75.7% accuracy) are comparable or better than the predictions of human experts.

  10. Cortical Dynamics of Contextually Cued Attentive Visual Learning and Search: Spatial and Object Evidence Accumulation

    ERIC Educational Resources Information Center

    Huang, Tsung-Ren; Grossberg, Stephen

    2010-01-01

    How do humans use target-predictive contextual information to facilitate visual search? How are consistently paired scenic objects and positions learned and used to more efficiently guide search in familiar scenes? For example, humans can learn that a certain combination of objects may define a context for a kitchen and trigger a more efficient…

  11. Task Specificity and the Influence of Memory on Visual Search: Comment on V and Wolfe (2012)

    E-print Network

    Hollingworth, Andrew

    2012-01-01

    COMMENTARY Task Specificity and the Influence of Memory on Visual Search: Comment on Võ and Wolfe (2012) Andrew Hollingworth University of Iowa Recent results from Võ and Wolfe (2012b) suggest not improve later search, but Võ and Wolfe used a relatively insensitive, between-subjects design. Here, we

  12. Memory for rejected distractors in visual search? Todd S. Horowitz and Jeremy M. Wolfe

    E-print Network

    Memory for rejected distractors in visual search? Todd S. Horowitz and Jeremy M. Wolfe Brigham). To test this assumption, Horowitz and Wolfe (1998) developed the randomized search paradigm, in which & Wolfe, in press; Pashler, 1997; Wolfe, 1998a). Although the modern study of attention began

  13. Coarse guidance by numerosity in visual search Ester Reijnen & Jeremy M. Wolfe &

    E-print Network

    Coarse guidance by numerosity in visual search Ester Reijnen & Jeremy M. Wolfe & Joseph items produces no or little increase in RT) can be labeled as "efficient search" (Wolfe, 1994, random allocations of attention to other items that lack the feature (Wolfe, 1994). It has repeatedly

  14. Contextual Cueing in Multiconjunction Visual Search Is Dependent on Color- and Configuration-Based Intertrial Contingencies

    ERIC Educational Resources Information Center

    Geyer, Thomas; Shi, Zhuanghua; Muller, Hermann J.

    2010-01-01

    Three experiments examined memory-based guidance of visual search using a modified version of the contextual-cueing paradigm (Jiang & Chun, 2001). The target, if present, was a conjunction of color and orientation, with target (and distractor) features randomly varying across trials (multiconjunction search). Under these conditions, reaction times…

  15. Evidence for a systematic component within scan paths in visual search

    Microsoft Academic Search

    Iain D. Gilchrist; Monika Harvey

    2006-01-01

    We present evidence that scan paths in visual search can include a systematic component. The task for subjects in the experiment was to search for a target that was either present or absent. With regular grid-like displays, participants generated more horizontal saccades than vertical saccades. Disruption of the grid structure in the display modulated but did not eliminate the systematic

  16. Memory Across Eye-Movements: 1= f Dynamic in Visual Search

    Microsoft Academic Search

    Deborah J. Aks; Gregory J. Zelinsky; Julien C. Sprott

    2002-01-01

    The ubiquity of apparently random behavior in visual search (e.g., Horowitz & Wolfe, 1998) has led to our proposal that the human oculomotor system has subtle deterministic properties that underlie its complex behavior. We report the results of one subject's performance in a challenging search task in which 10,215 fixations were accumulated. A number of statistical and spectral tests revealed

  17. Age Differences in Visual Search for Traffic Signs During a Simulated Conversation

    Microsoft Academic Search

    Lisa C. McPhee; Charles T. Scialfa; Wanda M. Dennis; Geoffrey Ho; Jeff K. Caird

    2004-01-01

    The effects of divided attention were examined in younger adults (M = 23 years) and older adults (M = 64 years) who searched for traffic signs in digitized images of traffic scenes. Sign search was executed under single-task and dual-task conditions in scenes containing either small or large amounts of visual clutter. For both age groups, clutter and the secondary

  18. Brief Report: Eye Movements during Visual Search Tasks Indicate Enhanced Stimulus Discriminability in Subjects with PDD

    ERIC Educational Resources Information Center

    Kemner, Chantal; van Ewijk, Lizet; van Engeland, Herman; Hooge, Ignace

    2008-01-01

    Subjects with PDD excel on certain visuo-spatial tasks, amongst which visual search tasks, and this has been attributed to enhanced perceptual discrimination. However, an alternative explanation is that subjects with PDD show a different, more effective search strategy. The present study aimed to test both hypotheses, by measuring eye movements…

  19. Toward Real-Time Visually Augmented Navigation for Autonomous Search and Inspection of Ship Hulls

    E-print Network

    Eustice, Ryan

    Toward Real-Time Visually Augmented Navigation for Autonomous Search and Inspection of Ship Hulls Abstract This paper reports on current research to automate the task of ship hull inspection and search mapping framework and show how we are now applying that framework to the task of automated ship

  20. Multimodal signals: enhancement and constraint of song motor patterns by visual display.

    PubMed

    Cooper, Brenton G; Goller, Franz

    2004-01-23

    Many birds perform visual signals during their learned songs, but little is known about the interrelationship between visual and vocal displays. We show here that male brown-headed cowbirds (Molothrus ater) synchronize the most elaborate wing movements of their display with atypically long silent periods in their song, potentially avoiding adverse biomechanical effects on sound production. Furthermore, expiratory effort for song is significantly reduced when cowbirds perform their wing display. These results show a close integration between vocal and visual displays and suggest that constraints and synergistic interactions between the motor patterns of multimodal signals influence the evolution of birdsong. PMID:14739462

  1. The NLP Swish Pattern: An Innovative Visualizing Technique.

    ERIC Educational Resources Information Center

    Masters, Betsy J.; And Others

    1991-01-01

    Describes swish pattern, one of many innovative therapeutic interventions that developers of neurolinguistic programing (NLP) have contributed to counseling profession. Presents brief overview of NLP followed by an explanation of the basic theory and expected outcomes of the swish. Presents description of the intervention process and case studies…

  2. Faceted visualization of three dimensional neuroanatomy by combining ontology with faceted search.

    PubMed

    Veeraraghavan, Harini; Miller, James V

    2014-04-01

    In this work, we present a faceted-search based approach for visualization of anatomy by combining a three dimensional digital atlas with an anatomy ontology. Specifically, our approach provides a drill-down search interface that exposes the relevant pieces of information (obtained by searching the ontology) for a user query. Hence, the user can produce visualizations starting with minimally specified queries. Furthermore, by automatically translating the user queries into the controlled terminology our approach eliminates the need for the user to use controlled terminology. We demonstrate the scalability of our approach using an abdominal atlas and the same ontology. We implemented our visualization tool on the opensource 3D Slicer software. We present results of our visualization approach by combining a modified Foundational Model of Anatomy (FMA) ontology with the Surgical Planning Laboratory (SPL) Brain 3D digital atlas, and geometric models specific to patients computed using the SPL brain tumor dataset. PMID:24006207

  3. Patterned-String Tasks: Relation between Fine Motor Skills and Visual-Spatial Abilities in Parrots

    PubMed Central

    Krasheninnikova, Anastasia

    2013-01-01

    String-pulling and patterned-string tasks are often used to analyse perceptual and cognitive abilities in animals. In addition, the paradigm can be used to test the interrelation between visual-spatial and motor performance. Two Australian parrot species, the galah (Eolophus roseicapilla) and the cockatiel (Nymphicus hollandicus), forage on the ground, but only the galah uses its feet to manipulate food. I used a set of string pulling and patterned-string tasks to test whether usage of the feet during foraging is a prerequisite for solving the vertical string pulling problem. Indeed, the two species used techniques that clearly differed in the extent of beak-foot coordination but did not differ in terms of their success in solving the string pulling task. However, when the visual-spatial skills of the subjects were tested, the galahs outperformed the cockatiels. This supports the hypothesis that the fine motor skills needed for advanced beak-foot coordination may be interrelated with certain visual-spatial abilities needed for solving patterned-string tasks. This pattern was also found within each of the two species on the individual level: higher motor abilities positively correlated with performance in patterned-string tasks. This is the first evidence of an interrelation between visual-spatial and motor abilities in non-mammalian animals. PMID:24376885

  4. Design of 3D visualization of search results: evolution and evaluation

    NASA Astrophysics Data System (ADS)

    Cugini, John V.; Laskowski, Sharon; Sebrechts, Marc M.

    2000-02-01

    We discuss the evolution of the NIST Information Retrieval Visualization Engine. This prototype employs modern interactive visualization techniques to provide easier access to a set of documents resulting from a query to a search engine. The motivation and evaluation of several design features, such as keywork to concept mapping, explicit clustering, the use of 3D vs. 2D, and the relationship of visualization to logical structure are described. In particular, the result of an extensive usability experiment show how visualization may lead to either increased or decreased cognitive load.

  5. Person, place, and past influence eye movements during visual search

    E-print Network

    Hidalgo-Sotelo, Barbara Irene

    What is the role of an individual’s past experience in guiding gaze in familiar environments? Contemporary models of search guidance suggest high level scene context is a strong predictor of where observers search in ...

  6. Color-based grouping and inhibition in visual search: Evidence from a probe detection analysis of preview search

    Microsoft Academic Search

    JASON J. BRAITHWAITE; Glyn W. Humphreys; Johan Hulleman

    2005-01-01

    In four experiments, we examined selection processes in visual search using a probe detection task to measure the allocation\\u000a of attention. Under preview search conditions, probes were harder to detect on old relative to new distractors (Experiment\\u000a 1). This cannot be attributed solely to low-level sensory factors (Experiment 2). In addition, probe detection was sensitive\\u000a to color-based grouping of old

  7. Visualization Tools for Real-time Search Algorithms

    Microsoft Academic Search

    Yoshitaka Kuwata; Paul R. Cohen

    1993-01-01

    Search methods are common mechanisms in problem solving. In many AI applications, they are used with heuristic functions to prune the search space and improve performance. In last three decades, much effort has been directed toward research on such heuristic functions and search methods by AI community. As it is very hard to build theoretical models for heuristic functions to

  8. Visual search for rare targets: distracter tuning as a mechanism for learning from repeated target-absent searches.

    PubMed

    Levin, Daniel T; Angelone, Bonnie L; Beck, Melissa R

    2011-08-01

    In the typical visual search experiment, participants search for targets that are present on half of the trials and absent on the other half. However, many real-world tasks involve targets that are present only occasionally. Given this, it is important to know how people deal with the problem of finding targets they have little experience with. One possibility is that they develop an awareness of the degree to which they have effectively completed a search through complex target-absent scenes. To test this hypothesis, we had participants complete two relatively long search tasks in which only a minority of trials included targets. Stimuli were cluttered real-world scenes, and targets were defined by category. We examined participants' ability to terminate search on the target-absent scenes based on an accurate assessment of scene difficulty. Scene difficulty was estimated by computing the mean correct-trial response time (RT) for each of the target-absent scenes across all participants. These group RTs were then correlated with each participants' individual correct-trial RTs for the same stimuli to assess the degree to which a given participant's search-termination times were correlated with those of the group. These correlations successfully predicted participants' target-detection success in both experiments. These experiments suggest that an integral part of visual search is the need to calibrate search behaviour to scenes of varying levels of complexity even when no targets are present. PMID:21751991

  9. Journal of Vision (2005) 5, 81-92 http://journalofvision.org/5/1/8/ 81 Setting up the target template in visual search

    E-print Network

    Jiang, Yuhong

    2005-01-01

    is essential in visual search. It biases visual attention to information that matches the target template in visual search Timothy J. Vickery Department of Psychology, Harvard University, Cambridge, MA-defining criteria. Extensive research in the past has examined visual search when the target is defined by fixed

  10. Nurses' Behaviors and Visual Scanning Patterns May Reduce Patient Identification Errors

    ERIC Educational Resources Information Center

    Marquard, Jenna L.; Henneman, Philip L.; He, Ze; Jo, Junghee; Fisher, Donald L.; Henneman, Elizabeth A.

    2011-01-01

    Patient identification (ID) errors occurring during the medication administration process can be fatal. The aim of this study is to determine whether differences in nurses' behaviors and visual scanning patterns during the medication administration process influence their capacities to identify patient ID errors. Nurse participants (n = 20)…

  11. Fourier Harmonic Approach for Visualizing Temporal Patterns of Gene Expression Data

    E-print Network

    Buffalo, State University of New York

    -specialized end-users. The first Fourier harmonic projection (FFHP) was in- troduced to translate the multiFourier Harmonic Approach for Visualizing Temporal Patterns of Gene Expression Data Li Zhang and Aidong Zhang Department of Computer Science and Engineering State University of New York at Buffalo

  12. Heterogeneous patterns of availability for detection during visual surveys: spatiotemporal variation in sea

    E-print Network

    Dill, Lawrence M.

    of availability bias during population surveys. Accounting for such trends may improve the reliability.g. conservation planning) based on survey data. Key-words: abundance estimation, availability bias, detectabilityHeterogeneous patterns of availability for detection during visual surveys: spatiotemporal

  13. Visual Query Language: Finding patterns in and relationships among time series data

    Microsoft Academic Search

    Karen Zita Haigh; Wendy Foslien; Valerie Guralnik

    2004-01-01

    Many scientific datasets archive a large number of variables over time. These timeseries data streams typically track many variables over relatively long periods of time, and therefore are often both wide and deep. In this paper, we describe the Visual Query Language (VQL) (3), a technology for locat- ing time series patterns in historical or real time data. The user

  14. Visualizing and Discovering Web Navigational Patterns Jiyang Chen, Lisheng Sun, Osmar R. Zaiane, Randy Goebel

    E-print Network

    Zaiane, Osmar R.

    Visualizing and Discovering Web Navigational Patterns Jiyang Chen, Lisheng Sun, Osmar R. Za, lisheng, zaiane, goebel}@cs.ualberta.ca ABSTRACT Web site structures are complex to analyze. Cross-referencing the web structure with navigational behaviour adds to the complexity of the analysis. However

  15. Fault diagnosis of internal combustion engines using visual dot patterns of acoustic and vibration signals

    Microsoft Academic Search

    Jian-Da Wu; Chao-Qin Chuang

    2005-01-01

    An investigation of the fault diagnosis technique in internal combustion engines based on the visual dot pattern of acoustic and vibration signals is presented in this paper. Acoustic emissions and vibration signals are well known as being able to be used for monitoring the conditions of rotating machineries. Most of the conventional methods for fault diagnosis using acoustic and vibration

  16. Visualizing patterns of protein uptake to porous media using confocal scanning laser microscopy

    Microsoft Academic Search

    Thomas Linden; Anders Ljunglöf; Lars Hagel; Maria-Regina Kula; Jörg Thömmes

    2002-01-01

    Confocal scanning laser microscopy has been used to visualize the uptake of fluorescence-labeled proteins to porous stationary phases in finite bath adsorption experiments. Reference proteins were labeled with three different fluorescent dyes and a porous cation exchanger was sequentially incubated with solutions of these protein–dye conjugates. This sequential incubation experiment was used to investigate the pattern of protein uptake during

  17. Visual Discovery of Patterns in Sparse Event Data Using Sentinel Event Alignment, Ranking, and Filtering

    Microsoft Academic Search

    Roman Stanchak; Alexander Quinn

    Temporal events are typically visualized on a time line indicating the date they occurred. This perspective is useful when the questions one wishes to answer are related to the date of occurrence. This view, however, makes it difficult to identify patterns related to the relative duration between events or the sequential order. We demonstrate how the simple notion of temporal

  18. An integrative and interactive framework for improving biomedical pattern discovery and visualization

    Microsoft Academic Search

    Haiying Wang; Francisco Azuaje; Norman D. Black

    2004-01-01

    Recent progress in medical sciences has led to an explosive growth of data. Due to its inherent complexity and diversity, mining such volumes of data to extract relevant knowledge represents an enormous challenge and opportunity. Interactive pattern discovery and visualization systems for biomedical data mining have received relatively little attention. Emphasis has been traditionally placed on automation and supervised classification

  19. Patterns of visual attention to faces and objects in autism spectrum disorder.

    PubMed

    McPartland, James C; Webb, Sara Jane; Keehn, Brandon; Dawson, Geraldine

    2011-02-01

    This study used eye-tracking to examine visual attention to faces and objects in adolescents with autism spectrum disorder (ASD) and typical peers. Point of gaze was recorded during passive viewing of images of human faces, inverted human faces, monkey faces, three-dimensional curvilinear objects, and two-dimensional geometric patterns. Individuals with ASD obtained lower scores on measures of face recognition and social-emotional functioning but exhibited similar patterns of visual attention. In individuals with ASD, face recognition performance was associated with social adaptive function. Results highlight heterogeneity in manifestation of social deficits in ASD and suggest that naturalistic assessments are important for quantifying atypicalities in visual attention. PMID:20499148

  20. On Assisting a Visual-Facial Affect Recognition System with Keyboard-Stroke Pattern Information

    NASA Astrophysics Data System (ADS)

    Stathopoulou, I.-O.; Alepis, E.; Tsihrintzis, G. A.; Virvou, M.

    Towards realizing a multimodal affect recognition system, we are considering the advantages of assisting a visual-facial expression recognition system with keyboard-stroke pattern information. Our work is based on the assumption that the visual-facial and keyboard modalities are complementary to each other and that their combination can significantly improve the accuracy in affective user models. Specifically, we present and discuss the development and evaluation process of two corresponding affect recognition subsystems, with emphasis on the recognition of 6 basic emotional states, namely happiness, sadness, surprise, anger and disgust as well as the emotion-less state which we refer to as neutral. We find that emotion recognition by the visual-facial modality can be aided greatly by keyboard-stroke pattern information and the combination of the two modalities can lead to better results towards building a multimodal affect recognition system.

  1. “A Textbook Case Revisited”: Visual Rhetoric and Series Patterning in the American Museum of Natural History's Horse Evolution Displays

    Microsoft Academic Search

    Jeremiah Dyehouse

    2011-01-01

    This article describes the development of visual rhetoric in a historically significant museum exhibit. The study documents rhetorical change in the museum's displays, specifically in visual series depicting the horse's evolutionary development. The study also exposes the purpose of series patterning in the renovated display and the multiple views on scientific visualization this display implies. Such an analysis suggests the

  2. Segmentation of objects from backgrounds in visual search tasks Jeremy M. Wolfe a,b,*, Aude Oliva a,b

    E-print Network

    Segmentation of objects from backgrounds in visual search tasks Jeremy M. Wolfe a,b,*, Aude Oliva a in Driver & Frackiwiak, 2001; Sanders & Donk, 1996; Wolfe, 1998a). However, the laboratory task: wolfe@search.bwh

  3. Binocular saccade coordination in reading and visual search: a developmental study in typical reader and dyslexic children

    PubMed Central

    Seassau, Magali; Gérard, Christophe Loic; Bui-Quoc, Emmanuel; Bucci, Maria Pia

    2014-01-01

    Studies dealing with developmental aspects of binocular eye movement behavior during reading are scarce. In this study we have explored binocular strategies during reading and visual search tasks in a large population of dyslexic and typical readers. Binocular eye movements were recorded using a video-oculography system in 43 dyslexic children (aged 8–13) and in a group of 42 age-matched typical readers. The main findings are: (i) ocular motor characteristics of dyslexic children are impaired in comparison to those reported in typical children in reading task; (ii) a developmental effect exists in reading in control children, in dyslexic children the effect of development was observed only on fixation durations; and (iii) ocular motor behavior in the visual search tasks is similar for dyslexic children and for typical readers, except for the disconjugacy during and after the saccade: dyslexic children are impaired in comparison to typical children. Data reported here confirms and expands previous studies on children’s reading. Both reading skills and binocular saccades coordination improve with age in typical readers. The atypical eye movement’s patterns observed in dyslexic children suggest a deficiency in the visual attentional processing as well as an impairment of the ocular motor saccade and vergence systems interaction. PMID:25400559

  4. Visual Search Performance in the Autism Spectrum II: The Radial Frequency Search Task with Additional Segmentation Cues

    ERIC Educational Resources Information Center

    Almeida, Renita A.; Dickinson, J. Edwin; Maybery, Murray T.; Badcock, Johanna C.; Badcock, David R.

    2010-01-01

    The Embedded Figures Test (EFT) requires detecting a shape within a complex background and individuals with autism or high Autism-spectrum Quotient (AQ) scores are faster and more accurate on this task than controls. This research aimed to uncover the visual processes producing this difference. Previously we developed a search task using radial…

  5. Repetition suppression and multi-voxel pattern similarity differentially track implicit and explicit visual memory.

    PubMed

    Ward, Emily J; Chun, Marvin M; Kuhl, Brice A

    2013-09-11

    Repeated exposure to a visual stimulus is associated with corresponding reductions in neural activity, particularly within visual cortical areas. It has been argued that this phenomenon of repetition suppression is related to increases in processing fluency or implicit memory. However, repetition of a visual stimulus can also be considered in terms of the similarity of the pattern of neural activity elicited at each exposure--a measure that has recently been linked to explicit memory. Despite the popularity of each of these measures, direct comparisons between the two have been limited, and the extent to which they differentially (or similarly) relate to behavioral measures of memory has not been clearly established. In the present study, we compared repetition suppression and pattern similarity as predictors of both implicit and explicit memory. Using functional magnetic resonance imaging, we scanned 20 participants while they viewed and categorized repeated presentations of scenes. Repetition priming (facilitated categorization across repetitions) was used as a measure of implicit memory, and subsequent scene recognition was used as a measure of explicit memory. We found that repetition priming was predicted by repetition suppression in prefrontal, parietal, and occipitotemporal regions; however, repetition priming was not predicted by pattern similarity. In contrast, subsequent explicit memory was predicted by pattern similarity (across repetitions) in some of the same occipitotemporal regions that exhibited a relationship between priming and repetition suppression; however, explicit memory was not related to repetition suppression. This striking double dissociation indicates that repetition suppression and pattern similarity differentially track implicit and explicit learning. PMID:24027275

  6. On the application of evolutionary pattern search algorithms

    SciTech Connect

    Hart, W.E.

    1997-02-01

    This paper presents an experimental evaluation of evolutionary pattern search algorithms (EPSAs). Our experimental evaluation of EPSAs indicates that EPSAs can achieve similar performance to EAs on challenging global optimization problems. Additionally, we describe a stopping rule for EPSAs that reliably terminated them near a stationary point of the objective function. The ability for EPSAs to reliably terminate near stationary points offers a practical advantage over other EAs, which are typically stopped by heuristic stopping rules or simple bounds on the number of iterations. Our experiments also illustrate how the rate of the crossover operator can influence the tradeoff between the number of iterations before termination and the quality of the solution found by an EPSA.

  7. Is there a limit to the superiority of individuals with ASD in visual search?

    PubMed

    Hessels, Roy S; Hooge, Ignace T C; Snijders, Tineke M; Kemner, Chantal

    2014-02-01

    Superiority in visual search for individuals diagnosed with autism spectrum disorder (ASD) is a well-reported finding. We administered two visual search tasks to individuals with ASD and matched controls. One showed no difference between the groups, and one did show the expected superior performance for individuals with ASD. These results offer an explanation, formulated in terms of load theory. We suggest that there is a limit to the superiority in visual search for individuals with ASD, related to the perceptual load of the stimuli. When perceptual load becomes so high that no additional task-(ir)relevant information can be processed, performance will be based on single stimulus identification, in which no differences between individuals with ASD and controls have been demonstrated. PMID:23838729

  8. Modeling the Visual Search of Displays: A Revised ACT-R Model of Icon Search Based on Eye-Tracking Data

    Microsoft Academic Search

    Michael D. Fleetwood; Michael D. Byrne

    2006-01-01

    Abstract Because of the visual nature of computer use, researchers and designers of computer systems would like to gain some insight into the visual search strategies of computer users. Icons, a common component of graphical user interfaces, serve as the focus for a set of studies aimed at (1) developing a detailed understanding of how people search for an icon

  9. Searching the Visual Arts: An Analysis of Online Information Access.

    ERIC Educational Resources Information Center

    Brady, Darlene; Serban, William

    1981-01-01

    A search for stained glass bibliographic information using DIALINDEX identified 57 DIALOG files from a variety of subject categories and 646 citations as relevant. Files include applied science, biological sciences, chemistry, engineering, environment/pollution, people, business research, and public affairs. Eleven figures illustrate the search

  10. Top-down guidance of visual search: A computational account

    Microsoft Academic Search

    Dietmar Heinke; Glyn W. Humphreys; Claire L. Tweed

    2006-01-01

    We present a revised version of the Selective Attention for Identification Model (SAIM), using an initial feature detection process to code edge orientations. We show that the revised SAIM can simulate both efficient and inefficient human search, that it shows search asymmetries, and that top-down expectancies for targets play a major role in the model's selection. Predictions of the model

  11. Scanners and drillers: Characterizing expert visual search through volumetric images

    E-print Network

    radiologists to search chest CTs for lung nodules that could indicate lung cancer. To search, radiologists scrolled up and down through a ``stack'' of 2-D chest CT ``slices.'' At each moment, we tracked eye et al., 2011). What would have been a single chest radiograph has become a chest CT (computed

  12. The effects of target location and target distinction on visual search in a depth display

    Microsoft Academic Search

    George Reis; Yan Liu; Paul Havig; Eric Heft

    2011-01-01

    Research of human-centered computing systems in industry should not avoid advances in visual display technology for safety,\\u000a warning, and interaction. Novel 3D displays that present information in real depth offer potential benefits. Previous research\\u000a has studied depth in visual search but depth was mostly not realized by real physical separation. Many areas of Human Factors\\u000a could be augmented with the

  13. Auditory, tactile, and multisensory cues facilitate search for dynamic visual stimuli

    Microsoft Academic Search

    Mary Kim Ngo; Charles Spence

    2010-01-01

    Presenting an auditory or tactile cue in temporal synchrony with a change in the color of a visual target can facilitate participants’\\u000a visual search performance. In the present study, we compared the magnitude of unimodal auditory, vibrotactile, and bimodal\\u000a (i.e., multisensory) cuing benefits when the nonvisual cues were presented in temporal synchrony with the changing of the\\u000a target’s color (Experiments

  14. Gene prediction by pattern recognition and homology search

    SciTech Connect

    Xu, Y.; Uberbacher, E.C.

    1996-05-01

    This paper presents an algorithm for combining pattern recognition-based exon prediction and database homology search in gene model construction. The goal is to use homologous genes or partial genes existing in the database as reference models while constructing (multiple) gene models from exon candidates predicted by pattern recognition methods. A unified framework for gene modeling is used for genes ranging from situations with strong homology to no homology in the database. To maximally use the homology information available, the algorithm applies homology on three levels: (1) exon candidate evaluation, (2) gene-segment construction with a reference model, and (3) (complete) gene modeling. Preliminary testing has been done on the algorithm. Test results show that (a) perfect gene modeling can be expected when the initial exon predictions are reasonably good and a strong homology exists in the database; (b) homology (not necessarily strong) in general helps improve the accuracy of gene modeling; (c) multiple gene modeling becomes feasible when homology exists in the database for the involved genes.

  15. Optimization of boiling water reactor control rod patterns using linear search

    Microsoft Academic Search

    T. Kiguchi; K. Doi; T. Fikuzaki; B. Frogner; C. Lin; A. B. Long

    1984-01-01

    A computer program for searching the optimal control rod pattern has been developed. The program is able to find a control rod pattern where the resulting power distribution is optimal in the sense that it is the closest to the desired power distribution, and it satisfies all operational constraints. The search procedure consists of iterative uses of two steps: sensitivity

  16. Mining patterns in persistent surveillance systems with smart query and visual analytics

    NASA Astrophysics Data System (ADS)

    Habibi, Mohammad S.; Shirkhodaie, Amir

    2013-05-01

    In Persistent Surveillance Systems (PSS) the ability to detect and characterize events geospatially help take pre-emptive steps to counter adversary's actions. Interactive Visual Analytic (VA) model offers this platform for pattern investigation and reasoning to comprehend and/or predict such occurrences. The need for identifying and offsetting these threats requires collecting information from diverse sources, which brings with it increasingly abstract data. These abstract semantic data have a degree of inherent uncertainty and imprecision, and require a method for their filtration before being processed further. In this paper, we have introduced an approach based on Vector Space Modeling (VSM) technique for classification of spatiotemporal sequential patterns of group activities. The feature vectors consist of an array of attributes extracted from generated sensors semantic annotated messages. To facilitate proper similarity matching and detection of time-varying spatiotemporal patterns, a Temporal-Dynamic Time Warping (DTW) method with Gaussian Mixture Model (GMM) for Expectation Maximization (EM) is introduced. DTW is intended for detection of event patterns from neighborhood-proximity semantic frames derived from established ontology. GMM with EM, on the other hand, is employed as a Bayesian probabilistic model to estimated probability of events associated with a detected spatiotemporal pattern. In this paper, we present a new visual analytic tool for testing and evaluation group activities detected under this control scheme. Experimental results demonstrate the effectiveness of proposed approach for discovery and matching of subsequences within sequentially generated patterns space of our experiments.

  17. Visual pattern discrimination by population retinal ganglion cells' activities during natural movie stimulation.

    PubMed

    Zhang, Ying-Ying; Wang, Ru-Bin; Pan, Xiao-Chuan; Gong, Hai-Qing; Liang, Pei-Ji

    2014-02-01

    In the visual system, neurons often fire in synchrony, and it is believed that synchronous activities of group neurons are more efficient than single cell response in transmitting neural signals to down-stream neurons. However, whether dynamic natural stimuli are encoded by dynamic spatiotemporal firing patterns of synchronous group neurons still needs to be investigated. In this paper we recorded the activities of population ganglion cells in bullfrog retina in response to time-varying natural images (natural scene movie) using multi-electrode arrays. In response to some different brief section pairs of the movie, synchronous groups of retinal ganglion cells (RGCs) fired with similar but different spike events. We attempted to discriminate the movie sections based on temporal firing patterns of single cells and spatiotemporal firing patterns of the synchronous groups of RGCs characterized by a measurement of subsequence distribution discrepancy. The discrimination performance was assessed by a classification method based on Support Vector Machines. Our results show that different movie sections of the natural movie elicited reliable dynamic spatiotemporal activity patterns of the synchronous RGCs, which are more efficient in discriminating different movie sections than the temporal patterns of the single cells' spike events. These results suggest that, during natural vision, the down-stream neurons may decode the visual information from the dynamic spatiotemporal patterns of the synchronous group of RGCs' activities. PMID:24465283

  18. Visual search in typically developing toddlers and toddlers with Fragile X or Williams syndrome.

    PubMed

    Scerif, Gaia; Cornish, Kim; Wilding, John; Driver, Jon; Karmiloff-Smith, Annette

    2004-02-01

    Visual selective attention is the ability to attend to relevant visual information and ignore irrelevant stimuli. Little is known about its typical and atypical development in early childhood Experiment 1 investigates typically developing toddlers' visual search for multiple targets on a touch-screen. Time to hit a target, distance between successively touched items, accuracy and error types revealed changes in 2- and 3-year-olds' vulnerability to manipulations of the search display. Experiment 2 examined search performance by toddlers with Fragile X syndrome (FXS) or Williams syndrome (WS). Both of these groups produced equivalent mean time and distance per touch as typically developing toddlers matched by chronological or mental age; but both produced a larger number of errors. Toddlers with WS confused distractors with targets more than the other groups; while toddlers with FXS perseverated on previously found targets. These findings provide information on how visual search typically develops in toddlers, and reveal distinct search deficits for atypically developing toddlers. PMID:15323123

  19. Pattern classification precedes region-average hemodynamic response in early visual cortex.

    PubMed

    Kohler, Peter J; Fogelson, Sergey V; Reavis, Eric A; Meng, Ming; Guntupalli, J Swaroop; Hanke, Michael; Halchenko, Yaroslav O; Connolly, Andrew C; Haxby, James V; Tse, Peter U

    2013-09-01

    How quickly can information about the neural response to a visual stimulus be detected in the hemodynamic response measured using fMRI? Multi-voxel pattern analysis (MVPA) uses pattern classification to detect subtle stimulus-specific information from patterns of responses among voxels, including information that cannot be detected in the average response across a given brain region. Here we use MVPA in combination with rapid temporal sampling of the fMRI signal to investigate the temporal evolution of classification accuracy and its relationship to the average regional hemodynamic response. In primary visual cortex (V1) stimulus information can be detected in the pattern of voxel responses more than a second before the average hemodynamic response of V1 deviates from baseline, and classification accuracy peaks before the peak of the average hemodynamic response. Both of these effects are restricted to early visual cortex, with higher level areas showing no difference or, in some cases, the opposite temporal relationship. These results have methodological implications for fMRI studies using MVPA because they demonstrate that information can be decoded from hemodynamic activity more quickly than previously assumed. PMID:23587693

  20. A Globally Convergent Augmented Lagrangian Pattern Search Algorithm for Optimization with General Constraints and Simple Bounds

    NASA Technical Reports Server (NTRS)

    Lewis, Robert Michael; Torczon, Virginia

    1998-01-01

    We give a pattern search adaptation of an augmented Lagrangian method due to Conn, Gould, and Toint. The algorithm proceeds by successive bound constrained minimization of an augmented Lagrangian. In the pattern search adaptation we solve this subproblem approximately using a bound constrained pattern search method. The stopping criterion proposed by Conn, Gould, and Toint for the solution of this subproblem requires explicit knowledge of derivatives. Such information is presumed absent in pattern search methods; however, we show how we can replace this with a stopping criterion based on the pattern size in a way that preserves the convergence properties of the original algorithm. In this way we proceed by successive, inexact, bound constrained minimization without knowing exactly how inexact the minimization is. So far as we know, this is the first provably convergent direct search method for general nonlinear programming.

  1. Parametric Modeling of Visual Search Efficiency in Real Scenes

    PubMed Central

    Zhang, Xing; Li, Qingquan; Zou, Qin; Fang, Zhixiang; Zhou, Baoding

    2015-01-01

    How should the efficiency of searching for real objects in real scenes be measured? Traditionally, when searching for artificial targets, e.g., letters or rectangles, among distractors, efficiency is measured by a reaction time (RT) × Set Size function. However, it is not clear whether the set size of real scenes is as effective a parameter for measuring search efficiency as the set size of artificial scenes. The present study investigated search efficiency in real scenes based on a combination of low-level features, e.g., visible size and target-flanker separation factors, and high-level features, e.g., category effect and target template. Visible size refers to the pixel number of visible parts of an object in a scene, whereas separation is defined as the sum of the flank distances from a target to the nearest distractors. During the experiment, observers searched for targets in various urban scenes, using pictures as the target templates. The results indicated that the effect of the set size in real scenes decreased according to the variances of other factors, e.g., visible size and separation. Increasing visible size and separation factors increased search efficiency. Based on these results, an RT × Visible Size × Separation function was proposed. These results suggest that the proposed function is a practicable predictor of search efficiency in real scenes. PMID:26030908

  2. Racial Differences in Spatial Job Search Patterns: Exploring the Causes and Consequences

    Microsoft Academic Search

    Michael A. Stoll; Steven Raphael

    2000-01-01

    In this paper, we present an analysis of the spatial job search patterns of black, white, and Latino workers in Los Angeles. We find that blacks and Latinos tend to search in areas where employment growth is low, whereas whites tend to search in areas where it is high. Moreover, over half of the mean racial and ethnic differences in

  3. Case study of visualizing global user download patterns using Google Earth and NASA World Wind

    NASA Astrophysics Data System (ADS)

    Zong, Ziliang; Job, Joshua; Zhang, Xuesong; Nijim, Mais; Qin, Xiao

    2012-01-01

    Geo-visualization is significantly changing the way we view spatial data and discover information. On the one hand, a large number of spatial data are generated every day. On the other hand, these data are not well utilized due to the lack of free and easily used data-visualization tools. This becomes even worse when most of the spatial data remains in the form of plain text such as log files. This paper describes a way of visualizing massive plain-text spatial data at no cost by utilizing Google Earth and NASA World Wind. We illustrate our methods by visualizing over 170,000 global download requests for satellite images maintained by the Earth Resources Observation and Science (EROS) Center of U.S. Geological Survey (USGS). Our visualization results identify the most popular satellite images around the world and discover the global user download patterns. The benefits of this research are: 1. assisting in improving the satellite image downloading services provided by USGS, and 2. providing a proxy for analyzing the "hot spot" areas of research. Most importantly, our methods demonstrate an easy way to geo-visualize massive textual spatial data, which is highly applicable to mining spatially referenced data and information on a wide variety of research domains (e.g., hydrology, agriculture, atmospheric science, natural hazard, and global climate change).

  4. Visual servoing to fish and catching using global\\/local GA search

    Microsoft Academic Search

    Mamoru Minami; Hidekazu Suzuki; Julien Agbanhan; Toshiyuki Asakura

    2001-01-01

    This paper presents a vision related technique for a manipulator real-time visual servoing. The method utilizes the global search feature of a genetic algorithm (GA) and a local search technique of the GA and also the unprocessed gray-scale image called here as raw-image, in order to perform recognition of a known target object being imaged. Also in GA process, the

  5. The Importance of the Eye Area in Face Identification Abilities and Visual Search Strategies in Persons with Asperger Syndrome

    ERIC Educational Resources Information Center

    Falkmer, Marita; Larsson, Matilda; Bjallmark, Anna; Falkmer, Torbjorn

    2010-01-01

    Partly claimed to explain social difficulties observed in people with Asperger syndrome, face identification and visual search strategies become important. Previous research findings are, however, disparate. In order to explore face identification abilities and visual search strategies, with special focus on the importance of the eye area, 24…

  6. Self-Organization of Spatio-Temporal Hierarchy via Learning of Dynamic Visual Image Patterns on Action Sequences

    PubMed Central

    Jung, Minju; Hwang, Jungsik; Tani, Jun

    2015-01-01

    It is well known that the visual cortex efficiently processes high-dimensional spatial information by using a hierarchical structure. Recently, computational models that were inspired by the spatial hierarchy of the visual cortex have shown remarkable performance in image recognition. Up to now, however, most biological and computational modeling studies have mainly focused on the spatial domain and do not discuss temporal domain processing of the visual cortex. Several studies on the visual cortex and other brain areas associated with motor control support that the brain also uses its hierarchical structure as a processing mechanism for temporal information. Based on the success of previous computational models using spatial hierarchy and temporal hierarchy observed in the brain, the current report introduces a novel neural network model for the recognition of dynamic visual image patterns based solely on the learning of exemplars. This model is characterized by the application of both spatial and temporal constraints on local neural activities, resulting in the self-organization of a spatio-temporal hierarchy necessary for the recognition of complex dynamic visual image patterns. The evaluation with the Weizmann dataset in recognition of a set of prototypical human movement patterns showed that the proposed model is significantly robust in recognizing dynamically occluded visual patterns compared to other baseline models. Furthermore, an evaluation test for the recognition of concatenated sequences of those prototypical movement patterns indicated that the model is endowed with a remarkable capability for the contextual recognition of long-range dynamic visual image patterns. PMID:26147887

  7. Misleading contextual cues: How do they affect visual search?

    Microsoft Academic Search

    Angela A. Manginelli; Stefan Pollmann

    2009-01-01

    Contextual cueing occurs when repetitions of the distractor configuration are implicitly learned. This implicit learning leads\\u000a to faster search times in repeated displays. Here, we investigated how search adapts to a change of the target location in\\u000a old displays from a consistent location in the learning phase to a consistent new location in the transfer phase. In agreement\\u000a with the

  8. Visualizing a High Recall Search Strategy Output for Undergraduates in an Exploration Stage of Researching a Term Paper.

    ERIC Educational Resources Information Center

    Cole, Charles; Mandelblatt, Bertie; Stevenson, John

    2002-01-01

    Discusses high recall search strategies for undergraduates and how to overcome information overload that results. Highlights include word-based versus visual-based schemes; five summarization and visualization schemes for presenting information retrieval citation output; and results of a study that recommend visualization schemes geared toward…

  9. 61.1: Kinematics of Visual Search by Tunnel Vision Patients with Augmented Vision See-Through HMD

    Microsoft Academic Search

    Gang Luo; Eli Peli

    2004-01-01

    An augmented vision see-through HMD, which displays a minified contour view of the real world over the residual visual field of tunnel vision patients, was evaluated in a visual search experiment. Kinematic evaluation of subjects' eye and head movements showed that tunnel vision patients could find and locate targets outside their visual fields faster and more efficiently with the device

  10. Modeling the Temporal Dynamics of IT Neurons in Visual Search: A Mechanism for Top-Down Selective Attention

    Microsoft Academic Search

    Marius Usher; Ernst Niebur

    1996-01-01

    We propose a neural model for object-oriented attention in which various visual stimuli (shapes, colors, letters, etc.) are represented by competing, mutually inhibitory, cell assemblies. The model's response to a sequence of cue and target stimuli mimics the neural responses in infero temporal (IT) visual cortex of monkeys performing a visual search task: enhanced response during the display of the

  11. Towards a framework for analysis of eye-tracking studies in the three dimensional environment: a study of visual search by experienced readers of endoluminal CT colonography

    PubMed Central

    Helbren, E; Phillips, P; Boone, D; Fanshawe, T R; Taylor, S A; Manning, D; Gale, A; Altman, D G; Mallett, S

    2014-01-01

    Objective: Eye tracking in three dimensions is novel, but established descriptors derived from two-dimensional (2D) studies are not transferable. We aimed to develop metrics suitable for statistical comparison of eye-tracking data obtained from readers of three-dimensional (3D) “virtual” medical imaging, using CT colonography (CTC) as a typical example. Methods: Ten experienced radiologists were eye tracked while observing eight 3D endoluminal CTC videos. Subsequently, we developed metrics that described their visual search patterns based on concepts derived from 2D gaze studies. Statistical methods were developed to allow analysis of the metrics. Results: Eye tracking was possible for all readers. Visual dwell on the moving region of interest (ROI) was defined as pursuit of the moving object across multiple frames. Using this concept of pursuit, five categories of metrics were defined that allowed characterization of reader gaze behaviour. These were time to first pursuit, identification and assessment time, pursuit duration, ROI size and pursuit frequency. Additional subcategories allowed us to further characterize visual search between readers in the test population. Conclusion: We propose metrics for the characterization of visual search of 3D moving medical images. These metrics can be used to compare readers' visual search patterns and provide a reproducible framework for the analysis of gaze tracking in the 3D environment. Advances in knowledge: This article describes a novel set of metrics that can be used to describe gaze behaviour when eye tracking readers during interpretation of 3D medical images. These metrics build on those established for 2D eye tracking and are applicable to increasingly common 3D medical image displays. PMID:24689842

  12. Comparison of visualized turbine endwall secondary flows and measured heat transfer patterns

    NASA Technical Reports Server (NTRS)

    Gaugler, R. E.; Russell, L. M.

    1983-01-01

    Various flow visualization techniques were used to define the secondary flows near the endwall in a large heat transfer data. A comparison of the visualized flow patterns and the measured Stanton number distribution was made for cases where the inlet Reynolds number and exit Mach number were matched. Flows were visualized by using neutrally buoyant helium-filled soap bubbles, by using smoke from oil soaked cigars, and by a few techniques using permanent marker pen ink dots and synthetic wintergreen oil. Details of the horseshoe vortex and secondary flows can be directly compared with heat transfer distribution. Near the cascade entrance there is an obvious correlation between the two sets of data, but well into the passage the effect of secondary flow is not as obvious.

  13. Visualizing magnetocrystalline anisotropy field distribution of patterned triangular L10 FePt nanodots

    NASA Astrophysics Data System (ADS)

    Zhong, Hai; Zhang, Kaiming; Wei, Dan; Wang, Sumei; Yuan, Jun

    2015-02-01

    Measuring magnetocrystalline anisotropy field distribution of patterned magnetic nanodots using a microscopically visualizing way is important for understanding some important magnetic behaviors such as switching field distribution (SFD) of patterned recording media. We present a detailed analysis of the remanent domain structures of L10-FePt triangular nanodots as revealed by high resolution magnetic force microscopy (MFM) with the help of micromagnetic simulation, showing that the domain structure diversity can effectively account for a dot-to-dot variation of the magnetocrystalline anisotropy field. Our method could shed light not only on understanding the fundamental causes of a wider SFD but also on designing future nanostructured magnetic devices.

  14. Neuronal dynamics of bottom-up and top-down processes in area V4 of macaque monkeys performing a visual search

    Microsoft Academic Search

    Tadashi Ogawa; Hidehiko Komatsu

    2006-01-01

    Visual selection is thought to be guided by both bottom-up intrinsic visual saliency and top-down visual attention. We examined how the relative importance of each of these processes dynamically changes over the course of a visual search in area V4 of two macaque monkeys. The animals were trained to perform a multidimensional visual search task in which a search array

  15. Patterns of Visual Attention to Faces and Objects in Autism Spectrum Disorder

    Microsoft Academic Search

    James C. McPartland; Sara Jane Webb; Brandon Keehn; Geraldine Dawson

    2011-01-01

    This study used eye-tracking to examine visual attention to faces and objects in adolescents with autism spectrum disorder\\u000a (ASD) and typical peers. Point of gaze was recorded during passive viewing of images of human faces, inverted human faces,\\u000a monkey faces, three-dimensional curvilinear objects, and two-dimensional geometric patterns. Individuals with ASD obtained\\u000a lower scores on measures of face recognition and social-emotional

  16. Neural responses to visual scenes reveals inconsistencies between fMRI adaptation and multivoxel pattern analysis

    Microsoft Academic Search

    Russell A. Epstein; Lindsay K. Morgan

    Human observers can recognize real-world visual scenes with great efficiency. Cortical regions such as the parahippocampal place area (PPA) and retrosplenial complex (RSC) have been implicated in scene recognition, but the specific representations supported by these regions are largely unknown. We used functional magnetic resonance imaging adaptation (fMRIa) and multi-voxel pattern analysis (MVPA) to explore this issue, focusing on whether

  17. Fast and adaptive network of spiking neurons for multi-view visual pattern recognition

    Microsoft Academic Search

    Simei Gomes Wysoski; Lubica Benuskova; Nikola Kasabov

    2008-01-01

    In this paper, we describe and evaluate a new spiking neural network (SNN) architecture and its corresponding learning procedure to perform fast and adaptive multi-view visual pattern recognition. The network is composed of a simplified type of integrate-and-fire neurons arranged hierarchically in four layers of two-dimensional neuronal maps. Using a Hebbian-based training, the network adaptively changes its structure in order

  18. Modeling the Visual Search of Displays: A Revised ACT-R/PM Model of Icon Search Based on Eye-Tracking and

    E-print Network

    Byrne, Mike

    Modeling the Visual Search of Displays: A Revised ACT-R/PM Model of Icon Search Based on Eye & Byrne, 2002) presented a study of "icon search" and a set of computational models of the task in the ACT-R set of computational models informed by the eye tracking study. 2. Previous Research We used ACT-R

  19. Modeling cognitive effects on visual search for targets in cluttered backgrounds

    NASA Astrophysics Data System (ADS)

    Snorrason, Magnus; Ruda, Harald; Hoffman, James

    1998-07-01

    To understand how a human operator performs visual search in complex scenes, it is necessary to take into account top- down cognitive biases in addition to bottom-up visual saliency effects. We constructed a model to elucidate the relationship between saliency and cognitive effects in the domain of visual search for distant targets in photo- realistic images of cluttered scenes. In this domain, detecting targets is difficult and requires high visual acuity. Sufficient acuity is only available near the fixation point, i.e. in the fovea. Hence, the choice of fixation points is the most important determinant of whether targets get detected. We developed a model that predicts the 2D distribution of fixation probabilities directly from an image. Fixation probabilities were computed as a function of local contrast (saliency effect) and proximity to the horizon (cognitive effect: distant targets are more likely to be found c close to the horizon). For validation, the model's predictions were compared to ensemble statistics of subjects' actual fixation locations, collected with an eye- tracker. The model's predictions correlated well with the observed data. Disabling the horizon-proximity functionality of the model significantly degraded prediction accuracy, demonstrating that cognitive effects must be accounted for when modeling visual search.

  20. Inter-trial priming does not affect attentional priority in asymmetric visual search

    PubMed Central

    Amunts, Liana; Yashar, Amit; Lamy, Dominique

    2014-01-01

    Visual search is considerably speeded when the target's characteristics remain constant across successive selections. Here, we investigated whether such inter-trial priming increases the target's attentional priority, by examining whether target repetition reduces search efficiency during serial search. As the study of inter-trial priming requires the target and distractors to exchange roles unpredictably, it has mostly been confined to singleton searches, which typically yield efficient search. We therefore resorted to two singleton searches known to yield relatively inefficient performance, that is, searches in which the target does not pop out. Participants searched for a veridical angry face among neutral ones or vice-versa, either upright or inverted (Experiment 1) or for a Q among Os or vice-versa (Experiment 2). In both experiments, we found substantial intertrial priming that did not improve search efficiency. In addition, intertrial priming was asymmetric and occurred only when the more salient target repeated. We conclude that intertrial priming does not modulate attentional priority allocation and that it occurs in asymmetric search only when the target is characterized by an additional feature that is consciously perceived. PMID:25221536

  1. Visual Search Asymmetries within Color-Coded and Intensity-Coded Displays

    ERIC Educational Resources Information Center

    Yamani, Yusuke; McCarley, Jason S.

    2010-01-01

    Color and intensity coding provide perceptual cues to segregate categories of objects within a visual display, allowing operators to search more efficiently for needed information. Even within a perceptually distinct subset of display elements, however, it may often be useful to prioritize items representing urgent or task-critical information.…

  2. What Are the Shapes of Response Time Distributions in Visual Search?

    ERIC Educational Resources Information Center

    Palmer, Evan M.; Horowitz, Todd S.; Torralba, Antonio; Wolfe, Jeremy M.

    2011-01-01

    Many visual search experiments measure response time (RT) as their primary dependent variable. Analyses typically focus on mean (or median) RT. However, given enough data, the RT distribution can be a rich source of information. For this paper, we collected about 500 trials per cell per observer for both target-present and target-absent displays…

  3. "Curing"the prevalence effect in visual search Brigham and Women's Hospital

    E-print Network

    prevalence visual search: Easy to produce, hard to cure. VSS. Absent Present Absent Present Miss Errors False Alarms More Misses Fewer FAs Low (2%)Low (2%) Old Data VSS `06: Full feedback,no retraining.0 1.5 Old Data VSS '06 "Retraining" Paradigm Prevalence Funded by Department of Homeland Security

  4. Controlling Attention With Noise: The Cue-Combination Model of Visual Search

    E-print Network

    Mozer, Michael C.

    College of Computer Science Northeastern University dfb@ccs.neu.edu Michael C. Mozer Institute of Cognitive Science University of Colorado at Boulder mozer@colorado.edu Abstract Visual search to explain data within a mechanistic framework (e.g., Mozer, 1991; Sandon, 1990, Itti & Koch, 1998). Perhaps

  5. Visual Search and Emotion: How Children with Autism Spectrum Disorders Scan Emotional Scenes

    ERIC Educational Resources Information Center

    Maccari, Lisa; Pasini, Augusto; Caroli, Emanuela; Rosa, Caterina; Marotta, Andrea; Martella, Diana; Fuentes, Luis J.; Casagrande, Maria

    2014-01-01

    This study assessed visual search abilities, tested through the flicker task, in children diagnosed with autism spectrum disorders (ASDs). Twenty-two children diagnosed with ASD and 22 matched typically developing (TD) children were told to detect changes in objects of central interest or objects of marginal interest (MI) embedded in either…

  6. Reliability of Macaque Frontal Eye Field Neurons Signaling Saccade Targets during Visual Search

    E-print Network

    Schall, Jeffrey D.

    Reliability of Macaque Frontal Eye Field Neurons Signaling Saccade Targets during Visual Search and selection, few have examined the reliability with which neurons represent relevant information. We moni was manipulated by varying the similarity in color between target and distractors. The reliability of individual

  7. A Maximum-Likelihood Strategy for Directing Attention during Visual Search

    E-print Network

    Duncan, James S.

    - likelihood (ML) decision rule. The strategy has two important properties: First, it can be usedA Maximum-Likelihood Strategy for Directing Attention during Visual Search Hemant D. Tagare, Member the target is present in them. We call the strategy for choosing image regions an ªattention strategy

  8. How You Move Is What You See: Action Planning Biases Selection in Visual Search

    ERIC Educational Resources Information Center

    Wykowska, Agnieszka; Schubo, Anna; Hommel, Bernhard

    2009-01-01

    Three experiments investigated the impact of planning and preparing a manual grasping or pointing movement on feature detection in a visual search task. The authors hypothesized that action planning may prime perceptual dimensions that provide information for the open parameters of that action. Indeed, preparing for grasping facilitated detection…

  9. Preattentive Face Processing: What Do Visual Search Experiments With Schematic Faces Tell Us?

    Microsoft Academic Search

    Gernot Horstmann

    2008-01-01

    In recent research, several experiments have tested a preattentive threat-advantage hypothesis that threatening or negative faces can be discriminated preattentively, by using the visual search paradigm. However, supporting evidence is nonuniform, giving rise to the suspicion that stimulus factors rather than the stimuli's category of facial threat versus friendliness are responsible for sporadic demonstrations of a threat advantage. However, it

  10. Processing efficiency in anxiety: Evidence from eye-movements during visual search

    Microsoft Academic Search

    Nazanin Derakshan; Ernst H. W. Koster

    2010-01-01

    It is generally held that anxiety is characterized by an attentional bias for threatening information. In recent years there has been an important debate whether these biases reside at the level of attentional selection (threat detection) or attentional processing after threat detection (attentional disengagement). In a visual search task containing emotional facial expressions, eye-movements were examined before and after threat

  11. Visual Search for Object Orientation Can Be Modulated by Canonical Orientation

    ERIC Educational Resources Information Center

    Ballaz, Cecile; Boutsen, Luc; Peyrin, Carole; Humphreys, Glyn W.; Marendaz, Christian

    2005-01-01

    The authors studied the influence of canonical orientation on visual search for object orientation. Displays consisted of pictures of animals whose axis of elongation was either vertical or tilted in their canonical orientation. Target orientation could be either congruent or incongruent with the object's canonical orientation. In Experiment 1,…

  12. H. Reiterer, G. Muler, T. M. Mann 1 A visual information seeking system for Web search

    E-print Network

    Reiterer, Harald

    of user interface for Web retrieval that supports the user in the information seeking process by providing In this paper we present the conception and the evaluation of a visual information seeking system for the Web paradigm of information retrieval systems for Web search simply presenting a long list of results (Zamir

  13. The Benefits of Augmenting Telephone Voice Menu Navigation with Visual Browsing and Search

    E-print Network

    Fernandes, Chris

    The Benefits of Augmenting Telephone Voice Menu Navigation with Visual Browsing and Search Min Yin interactive voice response (IVR) based telephone routing has long been recognized as a frustrating interaction experience. This paper presents a series of experiments examining the benefits of augmenting telephone voice

  14. Visual search for arbitrary objects in real scenes Jeremy M. Wolfe & George A. Alvarez &

    E-print Network

    Alvarez, George A.

    Visual search for arbitrary objects in real scenes Jeremy M. Wolfe & George A. Alvarez & Ruth & Donk, 1996; Wolfe 1998a, 1998b; Wolfe & Reynolds, 2008). The great bulk of this work has been done.g., Biederman, Blickle, Teitelbaum, & Klatsky, 1988; Wolfe, Horowitz, Kenner, Hyle, & Vasan, 2004; Yang

  15. Assessing the benefits of stereoscopic displays to visual search: methodology and initial findings

    NASA Astrophysics Data System (ADS)

    Godwin, Hayward J.; Holliman, Nick S.; Menneer, Tamaryn; Liversedge, Simon P.; Cave, Kyle R.; Donnelly, Nicholas

    2015-03-01

    Visual search is a task that is carried out in a number of important security and health related scenarios (e.g., X-ray baggage screening, radiography). With recent and ongoing developments in the technology available to present images to observers in stereoscopic depth, there has been increasing interest in assessing whether depth information can be used in complex search tasks to improve search performance. Here we outline the methodology that we developed, along with both software and hardware information, in order to assess visual search performance in complex, overlapping stimuli that also contained depth information. In doing so, our goal is to foster further research along these lines in the future. We also provide an overview with initial results of the experiments that we have conducted involving participants searching stimuli that contain overlapping objects presented on different depth planes to one another. Thus far, we have found that depth information does improve the speed (but not accuracy) of search, but only when the stimuli are highly complex and contain a significant degree of overlap. Depth information may therefore aid real-world search tasks that involve the examination of complex, overlapping stimuli.

  16. Case study of visualizing global user download patterns using Google Earth and NASA World Wind

    SciTech Connect

    Zong, Ziliang; Job, Joshua; Zhang, Xuesong; Nijim, Mais; Qin, Xiao

    2012-10-09

    Geo-visualization is significantly changing the way we view spatial data and discover information. On the one hand, a large number of spatial data are generated every day. On the other hand, these data are not well utilized due to the lack of free and easily used data-visualization tools. This becomes even worse when most of the spatial data remains in the form of plain text such as log files. This paper describes a way of visualizing massive plain-text spatial data at no cost by utilizing Google Earth and NASAWorld Wind. We illustrate our methods by visualizing over 170,000 global download requests for satellite images maintained by the Earth Resources Observation and Science (EROS) Center of U.S. Geological Survey (USGS). Our visualization results identify the most popular satellite images around the world and discover the global user download patterns. The benefits of this research are: 1. assisting in improving the satellite image downloading services provided by USGS, and 2. providing a proxy for analyzing the hot spot areas of research. Most importantly, our methods demonstrate an easy way to geovisualize massive textual spatial data, which is highly applicable to mining spatially referenced data and information on a wide variety of research domains (e.g., hydrology, agriculture, atmospheric science, natural hazard, and global climate change).

  17. The scaling of spatial attention in visual search and its modification in healthy aging

    PubMed Central

    GREENWOOD, P. M.; PARASURAMAN, RAJA

    2005-01-01

    A model of visual search (Greenwood & Parasuraman, 1999) postulating that visuospatial attention is composed of two processing components—shifting and scaling of a variable-gradient attentional focus—was tested in three experiments. Whereas young participants are able to dynamically constrict or expand the focus of visuospatial attention on the basis of prior information, in healthy aging individuals visuospatial attention becomes a poorly focused beam, unable to be constricted around one array element. In the present work, we sought to examine predictions of this view in healthy young and older participants. An attentional focus constricted in response to an element-sized precue had the strongest facilitatory effect on visual search. However, this was true only when the precue correctly indicated the location of a target fixed in size. When precues incorrectly indicated target location or when target size varied, the optimal spatial scale of attention for search was larger, encompassing a number of array elements. Healthy aging altered the deployment of attentional scaling: The benefit of valid precues on search initially (in participants 65–74 years of age) was increased but later (in those 75–85 years of age) was reduced. The results also provided evidence that cue size effects are attentional, not strategic. This evidence is consistent with the proposed model of attentional scaling in visual search. PMID:15095936

  18. Display format and highlight validity effects on search performance using complex visual displays

    NASA Technical Reports Server (NTRS)

    Donner, Kimberly A.; Mckay, Tim; O'Brien, Kevin M.; Rudisill, Marianne

    1991-01-01

    Display format and highlight validity were shown to affect visual display search performance; however, these studies were conducted on small, artificial displays of alphanumeric stimuli. A study manipulating these variables was conducted using realistic, complex Space Shuttle information displays. A 2x2x3 within-subjects analysis of variance found that search times were faster for items in reformatted displays than for current displays. The significant format by highlight validity interaction showed that there was little difference in response time to both current and reformatted displays when the highlight validity was applied; however, under the non or invalid highlight conditions, search times were faster with reformatted displays. Benefits of highlighting and reformatting displays to enhance search and the necessity to consider highlight validity and format characteristics in tandem for predicting search performance are discussed.

  19. Visual Servoing: A technology in search of an application

    SciTech Connect

    Feddema, J.T.

    1994-05-01

    Considerable research has been performed on Robotic Visual Servoing (RVS) over the past decade. Using real-time visual feedback, researchers have demonstrated that robotic systems can pick up moving parts, insert bolts, apply sealant, and guide vehicles. With the rapid improvements being made in computing and image processing hardware, one would expect that every robot manufacturer would have a RVS option by the end of the 1990s. So why aren`t the Fanucs, ABBs, Adepts, and Motomans of the world investing heavily in RVS? I would suggest four seasons: cost, complexity, reliability, and lack of demand. Solutions to the first three are approaching the point where RVS could be commercially available; however, the lack of demand is keeping RVS from becoming a reality in the near future. A new set of applications is needed to focus near term RVS development. These must be applications which currently do not have solutions. Once developed and working in one application area, the technology is more likely to quickly spread to other areas. DOE has several applications that are looking for technological solutions, such as agile weapons production, weapons disassembly, decontamination and dismantlement of nuclear facilities, and hazardous waste remediation. This paper will examine a few of these areas and suggest directions for application-driven visual servoing research.

  20. Peripheral vision and oculomotor control during visual search.

    PubMed

    Hooge, I T; Erkelens, C J

    1999-04-01

    The present study concerns the dynamics of multiple fixation search. We tried to gain insight into: (1) how the peripheral and foveal stimulus affect fixation duration; and (2) how fixation duration affects the peripheral target selection for saccades. We replicated the non-corroborating results of Luria and Strauss (1975) ('Eye movements during search for coded and uncoded targets', Perception and Psychophysics 17, 303-308) (saccades were selective), and Zelinsky (1996) (Using eye movements to assess the selectivity of search movements. Vision research 36(14), 2177-2187) (saccades were not selective), by manipulating the critical features for peripheral selection and discrimination separately. We found search to be more selective and efficient when the selection task was easy or when fixations were long-lasting. Remarkably, subjects did not increase their fixation durations when the peripheral selection task was more difficult. Only the discrimination task affected the fixation duration. This implies that the time available for peripheral target selection is determined mainly by the discrimination task. The results of the present experiment suggest that, besides the difficulty of the peripheral selection task, fixation duration is an important factor determining the selection of potential targets for eye movements. PMID:10343822

  1. Visual Diversification of Image Search Results Reinier H. van Leuken

    E-print Network

    Veltkamp, Remco

    , Spain roelof@yahoo-inc.com ABSTRACT Due to the reliance on the textual information associated and textual descriptions of photos prove to be powerful ways to describe and retrieve images that are uploaded-1-60558-487-4/09/04. models deployed on the Web and by these photo sharing sites rely heavily on search paradigms developed

  2. Mapping the Color Space of Saccadic Selectivity in Visual Search

    ERIC Educational Resources Information Center

    Xu, Yun; Higgins, Emily C.; Xiao, Mei; Pomplun, Marc

    2007-01-01

    Color coding is used to guide attention in computer displays for such critical tasks as baggage screening or air traffic control. It has been shown that a display object attracts more attention if its color is more similar to the color for which one is searching. However, what does "similar" precisely mean? Can we predict the amount of attention…

  3. Information Search: The Intersection of Visual and Semantic Space

    E-print Network

    Byrne, Mike

    and Michael D. Byrne Rice University Department of Psychology 6100 S. Main Street, MS-25, Houston, TX 77005 USA +1 713 348 4856 {tambo, byrne}@rice.edu Abstract In the context of an information search task pages). Intuition would say that a large, red headline that is a link and has a high degree

  4. Visualizing World-Wide Web Search Engine Results

    Microsoft Academic Search

    Sougata Mukherjea; Yoshinori Hara

    1999-01-01

    Most of the popular WWW search engines show the documents that match the users' queries as pages of scrolled lists. If lots of information is retrieved, this is not very user friendly. Moreover, there is no mechanism to easily determine documents linked to the retrieved documents or keywords related to the query terms. The paper presents a system that allows

  5. Initial Scene Representations Facilitate Eye Movement Guidance in Visual Search

    ERIC Educational Resources Information Center

    Castelhano, Monica S.; Henderson, John M.

    2007-01-01

    What role does the initial glimpse of a scene play in subsequent eye movement guidance? In 4 experiments, a brief scene preview was followed by object search through the scene via a small moving window that was tied to fixation position. Experiment 1 demonstrated that the scene preview resulted in more efficient eye movements compared with a…

  6. Irrelevant objects of expertise compete with faces during visual search

    E-print Network

    Palmeri, Thomas

    and car composites, judging whether the bottom half of an image was the same as the bottom half) remained constant, whereas the number of distractors from the irrelevant category (cars) varied. Search slopes, calculated as a function of the number of irrelevant cars, were correlated with car expertise

  7. An objective comparison of desktop search and visualization tools

    Microsoft Academic Search

    V. Lakshmi Narasimhan; Michael Lowe

    2010-01-01

    Information workers deal with many types of computer information on a daily basis including documents from office productivity application suites, web sites, emails and online calendar appointments. Indexing and search packages for these types of desktop information have recently become commercially available, but they are in their infancy. This short paper provides i) an objective comparison of the approaches used

  8. Incidental Learning Speeds Visual Search by Lowering Response Thresholds, Not by Improving Efficiency: Evidence from Eye Movements

    ERIC Educational Resources Information Center

    Hout, Michael C.; Goldinger, Stephen D.

    2012-01-01

    When observers search for a target object, they incidentally learn the identities and locations of "background" objects in the same display. This learning can facilitate search performance, eliciting faster reaction times for repeated displays. Despite these findings, visual search has been successfully modeled using architectures that maintain no…

  9. Visually-evoked pattern and photomyoclonic responses in video game and television epilepsy: case reports.

    PubMed

    Anyanwu, E; Watson, N A

    1996-01-01

    This research paper reports a case study of two male photosensitive epileptic patients, aged 14 and 16 years old respectively, whose epileptic seizures were often triggered by the flickers from television and video games respectively. The 14-year old patient had no family history of epilepsy, while the 16 year old had a family history of epilepsy. A comprehensive electroencephalogram (EEG), including hyperventilation, intermittent photic stimulation (IPS) and pattern stimulation were carried out on them and EEG abnormalities including photoparoxysmal responses (PPR) and generalized myoclonic responses were evoked. A thorough analysis of the EEG morphology of the myclonic responses and the clinical manifestations showed evidence of two separate entitles of seizures namely: visually evoked pattern-myoclonic responses (PTMR) and visually evoked photomyoclonic responses (PMR). PTMR was independent of flash rate and occurred before a PPR and at the same time as the flash rate, while PMR occurred after the PPR and was dependent on flash rate. These findings suggest that "Video Game" epilepsy is probably a pattern sensitive epilepsy, electronic screen being the source of the triggering patterns; hence, the morphology and the family histories and the myoclonic phenomena differ from those of pure photosensitive epilepsy. PMID:9201318

  10. Differential effects of parietal and frontal inactivations on reaction times distributions in a visual search task.

    PubMed

    Wardak, Claire; Ben Hamed, Suliann; Olivier, Etienne; Duhamel, Jean-René

    2012-01-01

    The posterior parietal cortex participates to numerous cognitive functions, from perceptual to attentional and decisional processes. However, the same functions have also been attributed to the frontal cortex. We previously conducted a series of reversible inactivations of the lateral intraparietal area (LIP) and of the frontal eye field (FEF) in the monkey which showed impairments in covert visual search performance, characterized mainly by an increase in the mean reaction time (RT) necessary to detect a contralesional target. Only subtle differences were observed between the inactivation effects in both areas. In particular, the magnitude of the deficit was dependant of search task difficulty for LIP, but not for FEF. In the present study, we re-examine these data in order to try to dissociate the specific involvement of these two regions, by considering the entire RT distribution instead of mean RT. We use the LATER model to help us interpret the effects of the inactivations with regard to information accumulation rate and decision processes. We show that: (1) different search strategies can be used by monkeys to perform visual search, either by processing the visual scene in parallel, or by combining parallel and serial processes; (2) LIP and FEF inactivations have very different effects on the RT distributions in the two monkeys. Although our results are not conclusive with regards to the exact functional mechanisms affected by the inactivations, the effects we observe on RT distributions could be accounted by an involvement of LIP in saliency representation or decision-making, and an involvement of FEF in attentional shifts and perception. Finally, we observe that the use of the LATER model is limited in the context of a visual search as it cannot fit all the behavioral strategies encountered. We propose that the diversity in search strategies observed in our monkeys also exists in individual human subjects and should be considered in future experiments. PMID:22754512

  11. Optimising Monte Carlo Search Strategies for Automated Pattern Detection

    E-print Network

    Rosenthal, Jeffrey S.

    vision and artificial intelligence. Among other things, it presents challenging problems in statistical, nose height, 2 #12;Figure 2. A successful search result (red). Figure 3. An unsuccessful search result

  12. Optimising Monte Carlo Search Strategies for Automated Pattern Detection

    E-print Network

    Rosenthal, Jeffrey S.

    vision and artificial intelligence. Among other things, it presents challenging problems in statistical, nose height, 2 #12; Figure 2. A successful search result (red). Figure 3. An unsuccessful search result

  13. Short wavelength automated perimetry, frequency doubling technology perimetry, and pattern electroretinography for prediction of progressive glaucomatous standard visual field defects

    Microsoft Academic Search

    Andreas U Bayer; Carl Erb

    2002-01-01

    PurposeTo evaluate the clinical use of a test battery of short wavelength automated perimetry (SWAP), frequency doubling technology perimetry (FDT), and pattern electroretinography (PERG) in predicting progressive glaucomatous visual field defects on standard automated perimetry (SAP).

  14. Query Suggestions for Mobile Search: Understanding Usage Patterns

    E-print Network

    Tomkins, Andrew

    Inc 1600 Amphitheatre Parkway, Mountain View, CA shumeet@google.com ABSTRACT Entering search terms that users who were asked to enter queries on a search interface with query suggestions rated their workload heavily on suggestions if they are provided. Users who were asked to enter queries on a search interface

  15. The Encoding of Temporally Irregular and Regular Visual Patterns in the Human Brain

    PubMed Central

    Zeki, Semir; Hulme, Oliver J.; Roulston, Barrie; Atiyah, Michael

    2008-01-01

    In the work reported here, we set out to study the neural systems that detect predictable temporal patterns and departures from them. We used functional magnetic resonance imaging (fMRI) to locate activity in the brains of subjects when they viewed temporally regular and irregular patterns produced by letters, numbers, colors and luminance. Activity induced by irregular sequences was located within dorsolateral prefrontal cortex, including an area that was responsive to irregular patterns regardless of the type of visual stimuli producing them. Conversely, temporally regular arrangements resulted in activity in the right frontal lobe (medial frontal gyrus), in the left orbito-frontal cortex and in the left pallidum. The results show that there is an abstractive system in the brain for detecting temporal irregularity, regardless of the source producing it. PMID:18478105

  16. Implications of sustained and transient channels for theories of visual pattern masking, saccadic suppression, and information processing

    Microsoft Academic Search

    Bruno G. Breitmeyer; Leo Ganz

    1976-01-01

    Reviews the visual masking literature in the context of known neurophysiological and psychophysical properties of the visual system's spatiotemporal response. The literature indicates that 3 consistent and typical pattern masking effects––(a) Type B forward or paracontrast, (b) Type B backward or metacontrast, and (c) Type A forward and backward––can be explained in terms of 3 simple sensory processes. It is

  17. Effects of Individual Health Topic Familiarity on Activity Patterns During Health Information Searches

    PubMed Central

    Moriyama, Koichi; Fukui, Ken–ichi; Numao, Masayuki

    2015-01-01

    Background Non-medical professionals (consumers) are increasingly using the Internet to support their health information needs. However, the cognitive effort required to perform health information searches is affected by the consumer’s familiarity with health topics. Consumers may have different levels of familiarity with individual health topics. This variation in familiarity may cause misunderstandings because the information presented by search engines may not be understood correctly by the consumers. Objective As a first step toward the improvement of the health information search process, we aimed to examine the effects of health topic familiarity on health information search behaviors by identifying the common search activity patterns exhibited by groups of consumers with different levels of familiarity. Methods Each participant completed a health terminology familiarity questionnaire and health information search tasks. The responses to the familiarity questionnaire were used to grade the familiarity of participants with predefined health topics. The search task data were transcribed into a sequence of search activities using a coding scheme. A computational model was constructed from the sequence data using a Markov chain model to identify the common search patterns in each familiarity group. Results Forty participants were classified into L1 (not familiar), L2 (somewhat familiar), and L3 (familiar) groups based on their questionnaire responses. They had different levels of familiarity with four health topics. The video data obtained from all of the participants were transcribed into 4595 search activities (mean 28.7, SD 23.27 per session). The most frequent search activities and transitions in all the familiarity groups were related to evaluations of the relevancy of selected web pages in the retrieval results. However, the next most frequent transitions differed in each group and a chi-squared test confirmed this finding (P<.001). Next, according to the results of a perplexity evaluation, the health information search patterns were best represented as a 5-gram sequence pattern. The most common patterns in group L1 were frequent query modifications, with relatively low search efficiency, and accessing and evaluating selected results from a health website. Group L2 performed frequent query modifications, but with better search efficiency, and accessed and evaluated selected results from a health website. Finally, the members of group L3 successfully discovered relevant results from the first query submission, performed verification by accessing several health websites after they discovered relevant results, and directly accessed consumer health information websites. Conclusions Familiarity with health topics affects health information search behaviors. Our analysis of state transitions in search activities detected unique behaviors and common search activity patterns in each familiarity group during health information searches. PMID:25783222

  18. Saved by a log: how do humans perform hybrid visual and memory search?

    PubMed

    Wolfe, Jeremy M

    2012-07-01

    Could you find 1 of your 1,000 Facebook friends in a crowd of 100? Even at a rate of 25 ms per comparison, determining that no friends were in the crowd would take more than 40 min if memory and visual search interacted linearly. In the experiment reported here, observers memorized pictures of 1 to 100 targets and then searched for any of these targets in visual displays of 1 to 16 objects. Response times varied linearly with visual set size but logarithmically with memory set size. Data from memory set sizes of 1 through 16 accurately predicted response times for different observers holding 100 objects in memory. The results would be consistent with a binary coding of visual objects in memory and are relevant to applied searches in which experts look for any of many items of interest (e.g., a radiologist running through a mental checklist of what might be wrong in a car-crash victim or an airport screener looking for any of a list of prohibited items in a carry-on bag). PMID:22623508

  19. Dynamic Spatial Coding within the Dorsal Frontoparietal Network during a Visual Search Task

    Microsoft Academic Search

    Wieland H. Sommer; Antje Kraft; Sein Schmidt; Manuel C. Olma; Stephan A. Brandt; Alain Chédotal

    2008-01-01

    To what extent are the left and right visual hemifields spatially coded in the dorsal frontoparietal attention network? In many experiments with neglect patients, the left hemisphere shows a contralateral hemifield preference, whereas the right hemisphere represents both hemifields. This pattern of spatial coding is often used to explain the right-hemispheric dominance of lesions causing hemispatial neglect. However, pathophysiological mechanisms

  20. Prevalence learning and decision making in a visual search task: an equivalent ideal observer approach

    NASA Astrophysics Data System (ADS)

    He, Xin; Samuelson, Frank; Zeng, Rongping; Sahiner, Berkman

    2015-03-01

    Research studies have observed an influence of target prevalence on observer performance for visual search tasks. The goal of this work is to develop models for prevalence effects on visual search. In a recent study by Wolfe et. al, a large scale observer study was conducted to understand the effects of varying target prevalence on visual search. Particularly, a total of 12 observers were recruited to perform 1000 trials of simulated baggage search as target prevalence varied sinusoidally from high to low and back to high. We attempted to model observers' behavior in prevalence learning and decision making. We modeled the observer as an equivalent ideal observer (EIO) with a prior belief of the signal prevalence. The use of EIO allows the application of ideal observer mathematics to characterize real observers' performance reading real-life images. For every given new image, the observer updates the belief on prevalence and adjusts his/her decision threshold according to utility theory. The model results agree well with the experimental results from the Wolfe study. The proposed models allow theoretical insights into observer behavior in learning prevalence and adjusting their decision threshold.

  1. Comparison of violet versus red laser exposures on visual search performance in humans.

    PubMed

    Previc, Fred H; McLin, Leon N; Novar, Brenda J; Kosnik, William

    2005-01-01

    Previous research suggests that the visual impairment of a violet laser is not highly localized on the retina, because the lens absorbs most short-wavelength visible light and partly retransmits it as a diffuse fluorescence at approximately 500 nm. The present study investigated whether a 405 nm violet diode laser more greatly impairs visual search performance in humans than does a 670 nm red diode laser, depending on target eccentricity. Participants had to locate a square among 15 diamonds spread throughout a visual search display while being exposed to a violet or red laser beam that was either continuous or flickering and presented either on-axis or 33 degrees off-axis. Whereas the continuous on-axis violet and red lasers had comparable effects on search performance when the target was located near the center of the beam, the violet laser disrupted processing of eccentric targets more than did the red laser. The search decrements were reduced for both lasers when the beams were flickered or presented off-axis. Both the bluish appearance and greater spatial spread of effect of the violet laser suggest that the unique impairment caused by a violet laser beam derives from its induced lens fluorescence. PMID:16229647

  2. A reference web architecture and patterns for real-time visual analytics on large streaming data

    NASA Astrophysics Data System (ADS)

    Kandogan, Eser; Soroker, Danny; Rohall, Steven; Bak, Peter; van Ham, Frank; Lu, Jie; Ship, Harold-Jeffrey; Wang, Chun-Fu; Lai, Jennifer

    2013-12-01

    Monitoring and analysis of streaming data, such as social media, sensors, and news feeds, has become increasingly important for business and government. The volume and velocity of incoming data are key challenges. To effectively support monitoring and analysis, statistical and visual analytics techniques need to be seamlessly integrated; analytic techniques for a variety of data types (e.g., text, numerical) and scope (e.g., incremental, rolling-window, global) must be properly accommodated; interaction, collaboration, and coordination among several visualizations must be supported in an efficient manner; and the system should support the use of different analytics techniques in a pluggable manner. Especially in web-based environments, these requirements pose restrictions on the basic visual analytics architecture for streaming data. In this paper we report on our experience of building a reference web architecture for real-time visual analytics of streaming data, identify and discuss architectural patterns that address these challenges, and report on applying the reference architecture for real-time Twitter monitoring and analysis.

  3. Visual search performance of patients with vision impairment: Effect of JPEG image enhancement

    PubMed Central

    Luo, Gang; Satgunam, PremNandhini; Peli, Eli

    2012-01-01

    Purpose To measure natural image search performance in patients with central vision impairment. To evaluate the performance effect for a JPEG based image enhancement technique using the visual search task. Method 150 JPEG images were presented on a touch screen monitor in either an enhanced or original version to 19 patients (visual acuity 0.4 to 1.2 logMAR, 6/15 to 6/90, 20/50 to 20/300) and 7 normally sighted controls (visual acuity ?0.12 to 0.1 logMAR, 6/4.5 to 6/7.5, 20/15 to 20/25). Each image fell into one of three categories: faces, indoors, and collections. The enhancement was realized by moderately boosting a mid-range spatial frequency band in the discrete cosine transform (DCT) coefficients of the image luminance component. Participants pointed to an object in a picture that matched a given target displayed at the upper-left corner of the monitor. Search performance was quantified by the percentage of correct responses, the median search time of correct responses, and an “integrated performance” measure – the area under the curve of cumulative correct response rate over search time. Results Patients were able to perform the search tasks but their performance was substantially worse than the controls. Search performances for the 3 image categories were significantly different (p?0.001) for all the participants, with searching for faces being the most difficult. When search time and correct response were analyzed separately, the effect of enhancement led to increase in one measure but decrease in another for many patients. Using the integrated performance, it was found that search performance declined with decrease in acuity (p=0.005). An improvement with enhancement was found mainly for the patients whose acuity ranged from 0.4 to 0.8 logMAR (6/15 to 6/38, 20/50 to 20/125). Enhancement conferred a small but significant improvement in integrated performance for indoor and collection images (p=0.025) in the patients. Conclusion Search performance for natural images can be measured in patients with impaired vision to evaluate the effect of image enhancement. Patients with moderate vision loss might benefit from the moderate level of enhancement used here. PMID:22540926

  4. Patterns of Glaucomatous Visual Field Loss in Sita Fields Automatically Identified Using Independent Component Analysis

    PubMed Central

    Goldbaum, Michael H.; Jang, Gil-Jin; Bowd, Chris; Hao, Jiucang; Zangwill, Linda M.; Liebmann, Jeffrey; Girkin, Christopher; Jung, Tzyy-Ping; Weinreb, Robert N.; Sample, Pamela A.

    2009-01-01

    Purpose: To determine if the patterns uncovered with variational Bayesian–independent component analysis–mixture model (VIM) applied to a large set of normal and glaucomatous fields obtained with the Swedish Interactive Thresholding Algorithm (SITA) are distinct, recognizable, and useful for modeling the severity of the field loss. Methods: SITA fields were obtained with the Humphrey Visual Field Analyzer (Carl Zeiss Meditec, Inc, Dublin, California) on 1,146 normal eyes and 939 glaucoma eyes from subjects followed by the Diagnostic Innovations in Glaucoma Study and the African Descent and Glaucoma Evaluation Study. VIM modifies independent component analysis (ICA) to develop separate sets of ICA axes in the cluster of normal fields and the 2 clusters of abnormal fields. Of 360 models, the model with the best separation of normal and glaucomatous fields was chosen for creating the maximally independent axes. Grayscale displays of fields generated by VIM on each axis were compared. SITA fields most closely associated with each axis and displayed in grayscale were evaluated for consistency of pattern at all severities. Results: The best VIM model had 3 clusters. Cluster 1 (1,193) was mostly normal (1,089, 95% specificity) and had 2 axes. Cluster 2 (596) contained mildly abnormal fields (513) and 2 axes; cluster 3 (323) held mostly moderately to severely abnormal fields (322) and 5 axes. Sensitivity for clusters 2 and 3 combined was 88.9%. The VIM-generated field patterns differed from each other and resembled glaucomatous defects (eg, nasal step, arcuate, temporal wedge). SITA fields assigned to an axis resembled each other and the VIM-generated patterns for that axis. Pattern severity increased in the positive direction of each axis by expansion or deepening of the axis pattern. Conclusions: VIM worked well on SITA fields, separating them into distinctly different yet recognizable patterns of glaucomatous field defects. The axis and pattern properties make VIM a good candidate as a preliminary process for detecting progression. PMID:20126490

  5. Visual Search Efficiency is Greater for Human Faces Compared to Animal Faces

    PubMed Central

    Simpson, Elizabeth A.; Mertins, Haley L.; Yee, Krysten; Fullerton, Alison; Jakobsen, Krisztina V.

    2015-01-01

    The Animate Monitoring Hypothesis proposes that humans and animals were the most important categories of visual stimuli for ancestral humans to monitor, as they presented important challenges and opportunities for survival and reproduction; however, it remains unknown whether animal faces are located as efficiently as human faces. We tested this hypothesis by examining whether human, primate, and mammal faces elicit similarly efficient searches, or whether human faces are privileged. In the first three experiments, participants located a target (human, primate, or mammal face) among distractors (non-face objects). We found fixations on human faces were faster and more accurate than primate faces, even when controlling for search category specificity. A final experiment revealed that, even when task-irrelevant, human faces slowed searches for non-faces, suggesting some bottom-up processing may be responsible for the human face search efficiency advantage. PMID:24962122

  6. Optimization of boiling water reactor control rod patterns using linear search

    SciTech Connect

    Kiguchi, T.; Doi, K.; Fikuzaki, T.; Frogner, B.; Lin, C.; Long, A.B.

    1984-10-01

    A computer program for searching the optimal control rod pattern has been developed. The program is able to find a control rod pattern where the resulting power distribution is optimal in the sense that it is the closest to the desired power distribution, and it satisfies all operational constraints. The search procedure consists of iterative uses of two steps: sensitivity analyses of local power and thermal margins using a three-dimensional reactor simulator for a simplified prediction model; linear search for the optimal control rod pattern with the simplified model. The optimal control rod pattern is found along the direction where the performance index gradient is the steepest. This program has been verified to find the optimal control rod pattern through simulations using operational data from the Oyster Creek Reactor.

  7. Flow pattern visualization in a mimic anaerobic digester: experimental and computational studies.

    PubMed

    Vesvikar, M S; Varma, R; Karim, K; Al-Dahhan, M

    2005-01-01

    Advanced non-invasive experiments like computer automated radioactive particle tracking and computed tomography along with computational fluid dynamics (CFD) simulations were performed in mimic anaerobic digesters to visualize their flow pattern and obtain hydrodynamic parameters. The mixing in the digester was provided by sparging gas at three different flow rates. The simulation results in terms of overall flow pattern, location of circulation cells and stagnant regions, trends of liquid velocity profiles, and volume of dead zones agree reasonably well with the experimental data. CFD simulations were also performed on different digester configurations. The effects of changing draft tube size, clearance, and shape of the tank bottoms were calculated to evaluate the effect of digester design on its flow pattern. Changing the draft tube clearance and height had no influence on the flow pattern or dead regions volume. However increasing the draft tube diameter or incorporating a conical bottom design helped in reducing the volume of the dead zones as compared to a flat bottom digester. The simulations showed that the gas flow rate sparged by a single point (0.5 cm diameter) sparger does not have appreciable effect on the flow pattern of the digesters. PMID:16180475

  8. Heuristic pattern search and its hybridization with simulated annealing for nonlinear global optimization

    Microsoft Academic Search

    Abdel-Rahman Hedar; Masao Fukushima

    2004-01-01

    In this article, we present a new approach of hybrid simulated annealing method for minimizing multimodel functions called the simulated annealing heuristic pattern search (SAHPS) method. Two subsidiary methods are proposed to achieve the final form of the global search method, SAHPS. First, we introduce the approximate descent direction (ADD) method, which is a derivative-free procedure with high ability of

  9. Blaming the victims of your own mistakes: How visual search accuracy influences evaluation of stimuli.

    PubMed

    Chetverikov, Andrey; Jóhannesson, Ómar I; Kristjánsson, Árni

    2015-09-01

    Even without explicit positive or negative reinforcement, experiences may influence preferences. According to the affective feedback in hypotheses testing account preferences are determined by the accuracy of hypotheses: correct hypotheses evoke positive affect, while incorrect ones evoke negative affect facilitating changes of hypotheses. Applying this to visual search, we suggest that accurate search should lead to more positive ratings of targets than distractors, while for errors targets should be rated more negatively. We test this in two experiments using time-limited search for a conjunction of gender and tint of faces. Accurate search led to more positive ratings for targets as compared to distractors or targets following errors. Errors led to more negative ratings for targets than for distractors. Critically, eye tracking revealed that the longer the fixation dwell times in target regions, the higher the target ratings for correct responses, and the lower the ratings for errors. The longer observers look at targets, the more positive their ratings if they answer correctly, and less positive, following errors. The findings support the affective feedback account and provide the first demonstration of negative effects on liking ratings following errors in visual search. PMID:25319749

  10. Modeling the Visual Search of Displays: A Revised ACT-R\\/PM Model of Icon Search Based on Eye-Tracking and Experimental Data

    Microsoft Academic Search

    Michael D. Fleetwood; Michael D. Byrne

    As computer use becomes more visual in nature, researchers and designers of computer systems would like to gain some insight into the visual search strategies of computer users and the characteristics of displays that encourage the most efficient of these strategies. Icons, which are becoming increasingly prevalent, serve as the focus for a set of studies on the interaction of

  11. Analysis and modeling of fixation point selection for visual search in cluttered backgrounds

    NASA Astrophysics Data System (ADS)

    Snorrason, Magnus; Hoffman, James; Ruda, Harald

    2000-07-01

    Hard-to-see targets are generally only detected by human observers once they have been fixated. Hence, understanding how the human visual system allocates fixation locations is necessary for predicting target detectability. Visual search experiments were conducted where observers searched for military vehicles in cluttered terrain. Instantaneous eye position measurements were collected using an eye tracker. The resulting data was partitioned into fixations and saccades, and analyzed for correlation with various image properties. The fixation data was used to validate out model for predicting fixation locations. This model generates a saliency map from bottom-up image features, such as local contrast. To account for top-down scene understanding effects, a separate cognitive bias map is generated. The combination of these two maps provides a fixation probability map, from which sequences of fixation points were generated.

  12. On the selection and evaluation of visual display symbology Factors influencing search and identification times

    NASA Technical Reports Server (NTRS)

    Remington, Roger; Williams, Douglas

    1986-01-01

    Three single-target visual search tasks were used to evaluate a set of cathode-ray tube (CRT) symbols for a helicopter situation display. The search tasks were representative of the information extraction required in practice, and reaction time was used to measure the efficiency with which symbols could be located and identified. Familiar numeric symbols were responded to more quickly than graphic symbols. The addition of modifier symbols, such as a nearby flashing dot or surrounding square, had a greater disruptive effect on the graphic symbols than did the numeric characters. The results suggest that a symbol set is, in some respects, like a list that must be learned. Factors that affect the time to identify items in a memory task, such as familiarity and visual discriminability, also affect the time to identify symbols. This analogy has broad implications for the design of symbol sets. An attempt was made to model information access with this class of display.

  13. Using facial emotional stimuli in visual search experiments: the arousal factor explains contradictory results.

    PubMed

    Lundqvist, Daniel; Juth, Pernilla; Öhman, Arne

    2014-01-01

    For more than two decades, visual search experiments using pictures of emotional faces as stimuli have generated contradictory results. Evidence of a superior detection of angry faces compared to happy faces have been mixed with an equal amount of evidence in the opposite direction. In this article, we review this literature, and examine the hypothesis that the neglected stimulus factor of emotional arousal may explain these contradictory results. Through an extensive reanalysis of results from our own laboratory as well as from other researchers, we show that the arousal factor systematically influences the outcome of the reviewed visual search experiments, and may thus provide a key to the historical contradictions within this research field. PMID:24341823

  14. RESEARCH REPORT Visual search and foraging compared in a large-scale search task

    E-print Network

    Gilchrist, Iain D.

    an array of distractor items. By manipu- lating factors such as the number of distractors, and the visual branded a `foraging facil- itator' (Klein and MacInnes 1999; cf. Hooge et al. 2005). Despite the putative

  15. Explaining Eye Movements in the Visual Search of Varying Density Layouts Tim Halverson (thalvers@cs.uoregon.edu)

    E-print Network

    Hornof, Anthony

    Explaining Eye Movements in the Visual Search of Varying Density Layouts Tim Halverson (thalvers.g. Byrne, 2001; Hornof & Halverson, 2003). Here we use fixation duration and number of fixations to inform

  16. The Perceptual Interaction of Simple and Complex Point Symbol Shapes and Background Textures in Visual Search on Tourist Maps

    E-print Network

    Alhosani, Naeema M.

    2009-05-31

    This study investigated visual search for simple and complex geometric and pictorial point symbols displayed on light and dark smooth and textured map backgrounds. Group-administered tests asked subjects to count occurrences ...

  17. Bilinear common spatial pattern for single-trial ERP-based rapid serial visual presentation triage

    NASA Astrophysics Data System (ADS)

    Yu, K.; Shen, K.; Shao, S.; Ng, W. C.; Li, X.

    2012-08-01

    Common spatial pattern (CSP) analysis is a useful tool for the feature extraction of event-related potentials (ERP). However, CSP is essentially time invariant, and thus unable to exploit the temporal information of ERP. This paper proposes a variant of CSP, namely bilinear common spatial pattern (BCSP), which is capable of accommodating both spatial and temporal information. BCSP generalizes CSP through iteratively optimizing bilinear filters. These bilinear filters constitute a spatio-temporal subspace in which the separation between two conditions is maximized. The method is unique in the sense that it is mathematically intuitive and simple, as all the bilinear filters are obtained by maximizing the power ratio as CSP does. The proposed method was evaluated on 20 subjects’ ERP data collected in rapid serial visual presentation triage experiments. The results show that BCSP achieved significantly higher average test accuracy (12.3% higher, p < 0.001).

  18. An efficient technique for revealing visual search strategies with classification images

    Microsoft Academic Search

    Abtine Tavassoli; Ian van der Linde; Alan C. Bovik; Lawrence K. Cormack

    2007-01-01

    We propose a novel variant of the classification image paradigm that allows us to rapidly reveal strategies used by observers\\u000a in visual search tasks. We make use of eye tracking, 1\\/f noise, and a grid-like stimulus ensemble and also introduce a new\\u000a classification taxonomy that distinguishes between foveal and peripheral processes. We tested our method for 3 human observers\\u000a and

  19. Attentional Capture by Salient Distractors during Visual Search Is Determined by Temporal Task Demands

    Microsoft Academic Search

    Monika Kiss; Anna Grubert; Anders Petersen; Martin Eimer

    The question whether attentional capture by salient but task-irrelevant visual stimuli is triggered in a bottom–up fashion or depends on top–down task settings is still unresolved. Strong support for bottom–up capture was obtained in the additional singleton task, in which search arrays were visible until response onset. Equally strong evidence for top–down control of attentional capture was obtained in spatial

  20. A Model of Object-Based Attention That Guides Active Visual Search to Behaviourally Relevant Locations

    Microsoft Academic Search

    Linda J. Lanyon; Susan L. Denham

    2004-01-01

    \\u000a During active visual search for a colour-orientation conjunction target, scan paths tend to be guided to target coloured locations\\u000a (Motter & Belky, 1998). An active vision model, using biased competition, is able to replicate this behaviour. At the cellular\\u000a level, the model replicates spatial and object-based attentional effects over time courses observed in single cell recordings\\u000a in monkeys (Chelazzi et

  1. The scaling of spatial attention in visual search and its modification in healthy aging

    Microsoft Academic Search

    P. M. Greenwood; Raja Parasuraman

    2004-01-01

    A model of visual search (Greenwood & Parasuraman, 1999) postulating that visuospatial attention is composed of two processing\\u000a components—shifting and scaling of a variable-gradient attentional focus—was tested in three experiments. Whereas young participants\\u000a are able to dynamically constrict or expand the focus of visuospatial attention on the basis of prior information, in healthy\\u000a aging individuals visuospatial attention becomes a poorly

  2. Visual Search for Size Is Influenced by a Background Texture Gradient

    Microsoft Academic Search

    Deborah J. Aks; James T. Enns

    1996-01-01

    Research on the perception of texture gradients has relied heavily on the subjective reports of observers engaged in free-viewing. We asked whether these findings generalized to speeded performance. Experiment 1 showed that an important aspect of subjective perception—size-constancy scaling with perceived distance—also predicted the speed of pop-out visual search for cylinders viewed against a texture gradient. Experiment 2 showed that

  3. Visual search for size is influenced by a background texture gradient

    Microsoft Academic Search

    Deborah J. Aks; James T. Enns

    1996-01-01

    Research on the perception of texture gradients has relied heavily on the subjective reports of observers engaged in free-viewing. We asked whether these findings generalized to speeded performance. Experiment 1 showed that an important aspect of subjective perception—size- constancy scaling with perceived distance—also predicted the speed of pop-out visual search for cylinders viewed against a texture gradient. Experiment 2 showed

  4. In Search of Naming Patterns: A Survey of Finnish Lake Names

    E-print Network

    Leino, Antti

    1 In Search of Naming Patterns: A Survey of Finnish Lake Names Antti Leino University of Helsinki suggested that such patterns can play an important role even when the names in question can be adequately is an attempt to address the issue: the goals were, first, to find regularities in the naming of Finnish lakes

  5. Do Synesthetes Have a General Advantage in Visual Search and Episodic Memory? A Case for Group Studies

    Microsoft Academic Search

    Nicolas Rothen; Beat Meier; Martin Giurfa

    2009-01-01

    BackgroundSome studies, most of them case-reports, suggest that synesthetes have an advantage in visual search and episodic memory tasks. The goal of this study was to examine this hypothesis in a group study.Methodology\\/Principal FindingsIn the present study, we tested thirteen grapheme-color synesthetes and we compared their performance on a visual search task and a memory test to an age-, handedness-,

  6. Do Synesthetes Have a General Advantage in Visual Search and Episodic Memory? A Case for Group Studies

    Microsoft Academic Search

    Nicolas Rothen; Beat Meier

    2009-01-01

    Background: Some studies, most of them case-reports, suggest that synesthetes have an advantage in visual search and episodic memory tasks. The goal of this study was to examine this hypothesis in a group study. Methodology\\/Principal Findings: In the present study, we tested thirteen grapheme-color synesthetes and we compared their performance on a visual search task and a memory test to

  7. Low-level properties of natural images predict topographic patterns of neural response in the ventral visual pathway

    PubMed Central

    Andrews, Timothy J.; Watson, David M.; Rice, Grace E.; Hartley, Tom

    2015-01-01

    Neuroimaging research over the past 20 years has begun to reveal a picture of how the human visual system is organized. A key distinction that has arisen from these studies is the difference in the organization of low-level and high-level visual regions. Low-level regions contain topographic maps that are tightly linked to properties of the image. In contrast, high-level visual areas are thought to be arranged in modules that are tightly linked to categorical or semantic information in the image. To date, an unresolved question has been how the strong functional selectivity for object categories in high-level visual regions might arise from the image-based representations found in low-level visual regions. Here, we review recent evidence suggesting that patterns of response in high-level visual areas may be better explained by response to image properties that are characteristic of different object categories. PMID:26024512

  8. Both memory and attention systems contribute to visual search for targets cued by implicitly learned context

    PubMed Central

    Giesbrecht, Barry; Sy, Jocelyn L.; Guerin, Scott A.

    2012-01-01

    Environmental context learned without awareness can facilitate visual processing of goal-relevant information. According to one view, the benefit of implicitly learned context relies on the neural systems involved in spatial attention and hippocampus-mediated memory. While this view has received empirical support, it contradicts traditional models of hippocampal function. The purpose of the present work was to clarify the influence of spatial context on visual search performance and on brain structures involved memory and attention. Event-related functional magnetic resonance imaging revealed that activity in the hippocampus as well as in visual and parietal cortex was modulated by learned visual context even though participants’ subjective reports and performance on a post-experiment recognition task indicated no explicit knowledge of the learned context. Moreover, the magnitude of the initial selective hippocampus response predicted the magnitude of the behavioral benefit due to context observed at the end of the experiment. The results suggest that implicit contextual learning is mediated by attention and memory and that these systems interact to support search of our environment. PMID:23099047

  9. Intelligent technique to search for patterns within images in massive databases

    SciTech Connect

    Vega, J.; Murari, A.; Pereira, A.; Portas, A.; Castro, P. [JET-EFDA, Culham Science Center, OX14 3DB Abingdon (United Kingdom)

    2008-10-15

    An image retrieval system for JET has been developed. The image database contains the images of the JET high speed visible camera. The system input is a pattern selected inside an image and the output is the group of frames (defined by their discharge numbers and time slices) that show patterns similar to the selected one. This approach is based on morphological pattern recognition and it should be emphasized that the pattern is found independently of its location in the frame. The technique encodes images into characters and, therefore, it transforms the pattern search into a character-matching problem.

  10. Protein Sequence Similarity Searches Using Patterns as Seeds

    Microsoft Academic Search

    Zheng Zhang; A. A. Schaffer; Webb Miller; Thomas L. Madden; David J. Lipman; Eugene V. Koonin; Stephen F. Altschul

    1998-01-01

    Protein families often are characterized by conservedsequence patterns or motifs. A researcher frequentlywishes to evaluate the significance of a specificpattern within a protein, or to exploit knowledge ofknown motifs to aid the recognition of greatly divergedbut homologous family members. To assist in theseefforts, the pattern-hit initiated BLAST (PHI-BLAST)program described here takes as input both a proteinsequence and a pattern of

  11. Searching for patterns in remote sensing image databases using neural networks

    NASA Technical Reports Server (NTRS)

    Paola, Justin D.; Schowengerdt, Robert A.

    1995-01-01

    We have investigated a method, based on a successful neural network multispectral image classification system, of searching for single patterns in remote sensing databases. While defining the pattern to search for and the feature to be used for that search (spectral, spatial, temporal, etc.) is challenging, a more difficult task is selecting competing patterns to train against the desired pattern. Schemes for competing pattern selection, including random selection and human interpreted selection, are discussed in the context of an example detection of dense urban areas in Landsat Thematic Mapper imagery. When applying the search to multiple images, a simple normalization method can alleviate the problem of inconsistent image calibration. Another potential problem, that of highly compressed data, was found to have a minimal effect on the ability to detect the desired pattern. The neural network algorithm has been implemented using the PVM (Parallel Virtual Machine) library and nearly-optimal speedups have been obtained that help alleviate the long process of searching through imagery.

  12. Transmural Ultrasound-based Visualization of Patterns of Action Potential Wave Propagation in Cardiac Tissue

    PubMed Central

    Luther, Stefan; Singh, Rupinder; Gilmour, Robert F.

    2010-01-01

    The pattern of action potential propagation during various tachyarrhythmias is strongly suspected to be composed of multiple re-entrant waves, but has never been imaged in detail deep within myocardial tissue. An understanding of the nature and dynamics of these waves is important in the development of appropriate electrical or pharmacological treatments for these pathological conditions. We propose a new imaging modality that uses ultrasound to visualize the patterns of propagation of these waves through the mechanical deformations they induce. The new method would have the distinct advantage of being able to visualize these waves deep within cardiac tissue. In this article, we describe one step that would be necessary in this imaging process—the conversion of these deformations into the action potential induced active stresses that produced them. We demonstrate that, because the active stress induced by an action potential is, to a good approximation, only nonzero along the local fiber direction, the problem in our case is actually overdetermined, allowing us to obtain a complete solution. Use of two- rather than three-dimensional displacement data, noise in these displacements, and/or errors in the measurements of the fiber orientations all produce substantial but acceptable errors in the solution. We conclude that the reconstruction of action potential-induced active stress from the deformation it causes appears possible, and that, therefore, the path is open to the development of the new imaging modality. PMID:20499183

  13. Structural connectivity patterns associated with the putative visual word form area and children's reading ability.

    PubMed

    Fan, Qiuyun; Anderson, Adam W; Davis, Nicole; Cutting, Laurie E

    2014-10-24

    With the advent of neuroimaging techniques, especially functional MRI (fMRI), studies have mapped brain regions that are associated with good and poor reading, most centrally a region within the left occipito-temporal/fusiform region (L-OT/F) often referred to as the visual word form area (VWFA). Despite an abundance of fMRI studies of the putative VWFA, research about its structural connectivity has just started. Provided that the putative VWFA may be connected to distributed regions in the brain, it remains unclear how this network is engaged in constituting a well-tuned reading circuitry in the brain. Here we used diffusion MRI to study the structural connectivity patterns of the putative VWFA and surrounding areas within the L-OT/F in children with typically developing (TD) reading ability and with word recognition deficits (WRD; sometimes referred to as dyslexia). We found that L-OT/F connectivity varied along a posterior-anterior gradient, with specific structural connectivity patterns related to reading ability in the ROIs centered upon the putative VWFA. Findings suggest that the architecture of the putative VWFA connectivity is fundamentally different between TD and WRD, with TD showing greater connectivity to linguistic regions than WRD, and WRD showing greater connectivity to visual and parahippocampal regions than TD. Findings thus reveal clear structural abnormalities underlying the functional abnormalities in the putative VWFA in WRD. PMID:25152466

  14. Three-dimensional visualization for evaluating automated, geomorphic pattern-recognition analyses of crustal structures

    NASA Astrophysics Data System (ADS)

    Foley, M. G.

    1991-02-01

    We are developing and applying a suite of automated remote geologic analysis (RGA) methods at Pacific Northwest Laboratory (PNL) for extracting structural and tectonic patterns from digital models of topography and other spatially registered geophysical data. In analyzing a map area, the geologist employs a variety of spatial representations (e.g., topographic maps; oblique, vertical and vertical stereographic aerial photographs; satellite-sensor images) in addition to actual field observations to provide a basis for recognizing features (patterns) diagnostic or suggestive of various geologic and geomorphic features. We intend that our automated analyses of digital models of elevation use the same photogeologic pattern-recognition methods as the geologist's; otherwise there is no direct basis for manually evaluating results of the automated analysis. Any system for automating geologic analysis should extend the geologist's pattern-recognition abilities and quantify them, rather than replace them. This requirement means that results of automated structural pattern-recognition analyses must be evaluated by geologists using the same method that would be employed in manual field checking: visual examination of the three-dimensional relationships among rocks, erosional patterns, and identifiable structures. Interactive computer-graphics in quantitative (i.e., spatially registered), simulated three-dimensional perspective and stereo are thus critical to the integration and interpretation of topography, imagery, point data, RGA-identified fracture/fault planes, stratigraphy, contoured geophysical data, nonplanar surfaces, boreholes, and three-dimensional zones (e.g., crush zones at fracture intersections). This graphical interaction presents the megabytes of digital geologic and geophysical data to the geologist in the same spatial format that field observations would take, permitting direct evaluation of RGA methods and results.

  15. Gaze and visual search strategies of children with Asperger syndrome/high functioning autism viewing a magic trick.

    PubMed

    Joosten, Annette; Girdler, Sonya; Albrecht, Matthew A; Horlin, Chiara; Falkmer, Marita; Leung, Denise; Ordqvist, Anna; Fleischer, Håkan; Falkmer, Torbjörn

    2014-05-27

    Abstract Objective: To examine visual search patterns and strategies used by children with and without Asperger syndrome/high functioning autism (AS/HFA) while watching a magic trick. Limited responsivity to gaze cues is hypothesised to contribute to social deficits in children with AS/HFA. Methods: Twenty-one children with AS/HFA and 31 matched peers viewed a video of a gaze-cued magic trick twice. Between the viewings, they were informed about how the trick was performed. Participants' eye movements were recorded using a head-mounted eye-tracker. Results: Children with AS/HFA looked less frequently and had shorter fixation on the magician's direct and averted gazes during both viewings and more frequently at not gaze-cued objects and on areas outside the magician's face. After being informed of how the trick was conducted, both groups made fewer fixations on gaze-cued objects and direct gaze. Conclusions: Information may enhance effective visual strategies in children with and without AS/HFA. PMID:24866104

  16. Modeling visual search using three-parameter probability functions in a hierarchical Bayesian framework.

    PubMed

    Lin, Yi-Shin; Heinke, Dietmar; Humphreys, Glyn W

    2015-04-01

    In this study, we applied Bayesian-based distributional analyses to examine the shapes of response time (RT) distributions in three visual search paradigms, which varied in task difficulty. In further analyses we investigated two common observations in visual search-the effects of display size and of variations in search efficiency across different task conditions-following a design that had been used in previous studies (Palmer, Horowitz, Torralba, & Wolfe, Journal of Experimental Psychology: Human Perception and Performance, 37, 58-71, 2011; Wolfe, Palmer, & Horowitz, Vision Research, 50, 1304-1311, 2010) in which parameters of the response distributions were measured. Our study showed that the distributional parameters in an experimental condition can be reliably estimated by moderate sample sizes when Monte Carlo simulation techniques are applied. More importantly, by analyzing trial RTs, we were able to extract paradigm-dependent shape changes in the RT distributions that could be accounted for by using the EZ2 diffusion model. The study showed that Bayesian-based RT distribution analyses can provide an important means to investigate the underlying cognitive processes in search, including stimulus grouping and the bottom-up guidance of attention. PMID:25678272

  17. Training shortens search times in children with visual impairment accompanied by nystagmus

    PubMed Central

    Huurneman, Bianca; Boonstra, F. Nienke

    2014-01-01

    Perceptual learning (PL) can improve near visual acuity (NVA) in 4–9 year old children with visual impairment (VI). However, the mechanisms underlying improved NVA are unknown. The present study compares feature search and oculomotor measures in 4–9 year old children with VI accompanied by nystagmus (VI+nys [n = 33]) and children with normal vision (NV [n = 29]). Children in the VI+nys group were divided into three training groups: an experimental PL group, a control PL group, and a magnifier group. They were seen before (baseline) and after 6 weeks of training. Children with NV were only seen at baseline. The feature search task entailed finding a target E among distractor E's (pointing right) with element spacing varied in four steps: 0.04°, 0.5°, 1°, and 2°. At baseline, children with VI+nys showed longer search times, shorter fixation durations, and larger saccade amplitudes than children with NV. After training, all training groups showed shorter search times. Only the experimental PL group showed prolonged fixation duration after training at 0.5° and 2° spacing, p's respectively 0.033 and 0.021. Prolonged fixation duration was associated with reduced crowding and improved crowded NVA. One of the mechanisms underlying improved crowded NVA after PL in children with VI+nys seems to be prolonged fixation duration. PMID:25309473

  18. Visual search and attention in blue jays (Cyanocitta cristata): Associative cuing and sequential priming.

    PubMed

    Goto, Kazuhiro; Bond, Alan B; Burks, Marianna; Kamil, Alan C

    2014-04-01

    Visual search for complex natural targets requires focal attention, either cued by predictive stimulus associations or primed by a representation of the most recently detected target. Because both processes can focus visual attention, cuing and priming were compared in an operant search task to evaluate their relative impacts on performance and to determine the nature of their interaction in combined treatments. Blue jays were trained to search for pairs of alternative targets among distractors. Informative or ambiguous color cues were provided before each trial, and targets were presented either in homogeneous blocked sequences or in constrained random order. Initial task acquisition was facilitated by priming in general, but was significantly retarded when targets were both cued and primed, indicating that the two processes interfered with each other during training. At asymptote, attentional effects were manifested mainly in inhibition, increasing latency in miscued trials and decreasing accuracy on primed trials following an unexpected target switch. A combination of cuing and priming was found to interfere with performance in such unexpected trials, apparently a result of the limited capacity of working memory. Because the ecological factors that promote priming or cuing are rather disparate, it is not clear whether they ever simultaneously contribute to natural predatory search. PMID:24893217

  19. Visual Search and Attention in Blue Jays (Cyanocitta cristata): Associative Cuing and Sequential Priming

    PubMed Central

    Goto, Kazuhiro; Bond, Alan B.; Burks, Marianna; Kamil, Alan C.

    2014-01-01

    Visual search for complex natural targets requires focal attention, either cued by predictive stimulus associations or primed by a representation of the most recently detected target. Since both processes can focus visual attention, cuing and priming were compared in an operant search task to evaluate their relative impacts on performance and to determine the nature of their interaction in combined treatments. Blue jays were trained to search for pairs of alternative targets among distractors. Informative or ambiguous color cues were provided prior to each trial, and targets were presented either in homogeneous blocked sequences or in constrained random order. Initial task acquisition was facilitated by priming in general, but was significantly retarded when targets were both cued and primed, indicating that the two processes interfered with each other during training. At asymptote, attentional effects were manifested mainly in inhibition, increasing latency in miscued trials and decreasing accuracy on primed trials following an unexpected target switch. A combination of cuing and priming was found to interfere with performance in such unexpected trials, apparently a result of the limited capacity of working memory. Because the ecological factors that promote priming and cuing are rather disparate, it is not clear whether they ever jointly and simultaneously contribute to natural predatory search. PMID:24893217

  20. Training shortens search times in children with visual impairment accompanied by nystagmus.

    PubMed

    Huurneman, Bianca; Boonstra, F Nienke

    2014-01-01

    Perceptual learning (PL) can improve near visual acuity (NVA) in 4-9 year old children with visual impairment (VI). However, the mechanisms underlying improved NVA are unknown. The present study compares feature search and oculomotor measures in 4-9 year old children with VI accompanied by nystagmus (VI+nys [n = 33]) and children with normal vision (NV [n = 29]). Children in the VI+nys group were divided into three training groups: an experimental PL group, a control PL group, and a magnifier group. They were seen before (baseline) and after 6 weeks of training. Children with NV were only seen at baseline. The feature search task entailed finding a target E among distractor E's (pointing right) with element spacing varied in four steps: 0.04°, 0.5°, 1°, and 2°. At baseline, children with VI+nys showed longer search times, shorter fixation durations, and larger saccade amplitudes than children with NV. After training, all training groups showed shorter search times. Only the experimental PL group showed prolonged fixation duration after training at 0.5° and 2° spacing, p's respectively 0.033 and 0.021. Prolonged fixation duration was associated with reduced crowding and improved crowded NVA. One of the mechanisms underlying improved crowded NVA after PL in children with VI+nys seems to be prolonged fixation duration. PMID:25309473

  1. Tactile search for change has less memory than visual search for change.

    PubMed

    Yoshida, Takako; Yamaguchi, Ayumi; Tsutsui, Hideomi; Wake, Tenji

    2015-05-01

    Haptic perception of a 2D image is thought to make heavy demands on working memory. During active exploration, humans need to store the latest local sensory information and integrate it with kinesthetic information from hand and finger locations in order to generate a coherent perception. This tactile integration has not been studied as extensively as visual shape integration. In the current study, we compared working-memory capacity for tactile exploration to that of visual exploration as measured in change-detection tasks. We found smaller memory capacity during tactile exploration (approximately 1 item) compared with visual exploration (2-10 items). These differences generalized to position memory and could not be attributed to insufficient stimulus-exposure durations, acuity differences between modalities, or uncertainty over the position of items. This low capacity for tactile memory suggests that the haptic system is almost amnesic when outside the fingertips and that there is little or no cross-position integration. PMID:25724516

  2. LCD versus CRT displays: a comparison of visual search performance for colored symbols.

    PubMed

    Hollands, J G; Parker, H A; McFadden, S; Boothby, R

    2002-01-01

    Visual search performance for tactical symbols was examined with liquid-crystal (LCD) and cathode-ray tube (CRT) displays. Twenty-four adult participants (19 men, 5 women; mean age 41 years) searched for navy tactical display symbols on a map background. LCD and CRT displays of similar size and resolution (52 cm diagonal, 1280 x 1024 pixels) were used. Viewing angle (0 degrees vs. 60 degrees of azimuth), set size, target color (blue, red, or white), target presence, and search type (feature vs. conjunction) were also manipulated. Participants showed reduced sensitivity for red and blue symbols viewed 60 degrees off axis with the LCD relative to on-axis LCD, or to the CRT on or off axis. Colored symbols viewed off axis on the LCD produced longer response times in feature search and lower search efficiency in conjunction search. The results argue against the use of current LCD technology when off-axis viewing is likely and color coding is used. PMID:12452269

  3. The effects of increasing target prevalence on information processing during visual search.

    PubMed

    Godwin, Hayward J; Menneer, Tamaryn; Cave, Kyle R; Thaibsyah, Michael; Donnelly, Nick

    2015-04-01

    The proportion of trials on which a target is presented (referred to as the target prevalence) during visual search influences the probability that the target will be detected. As prevalence increases, participants become biased toward reporting that the target is present. This bias results in an increase in detection rates for the target, coupled with an increased likelihood of making a false alarm. Previous work has demonstrated that, as prevalence increases, participants spend an increasing period of time searching on target-absent trials. The goal of the present study was to determine the information processing during the additional time spent searching on target-absent trials as prevalence increased. We recorded participants' eye movement behavior as they were engaged in low-prevalence (25% target-present trials), medium-prevalence (50%), or high-prevalence (75%) search. Increased prevalence primarily influenced search by increasing the time spent examining objects in the display, rather than by increasing the proportion of objects examined in each display. In addition, the additional time spent examining objects in high-prevalence target-absent trials was the result of revisiting objects. We discuss the implications of these results in relation to current models of search as well as ongoing efforts to alleviate the prevalence effect. PMID:25023956

  4. Onset of background dynamic noise attenuates preview benefit in inefficient visual search.

    PubMed

    Osugi, Takayuki; Murakami, Ikuya

    2015-07-01

    When certain distractors (old items) appear before others (new items) during an inefficient visual search task, observers exclude the old items from the search (preview benefit), possibly because their locations are deprioritized relative to the locations of the new items. We examined whether participants were able to ignore task-irrelevant changes in a scene (i.e., the onset of repetitive changes, continual repetitive changes, and the cessation of repetitive changes in the background), while performing a preview search task. The results indicated that, when the noise continually changed position throughout each trial, or when dynamic noise was changed to static noise simultaneous with the appearance of the search display, the preview benefit remained. In contrast, when the static background noise was changed to dynamic background noise, simultaneous with the appearance of the search display, this task-irrelevant background event abolished the preview benefit on search efficiency. Therefore, we conclude that the onset of task-irrelevant repetitive changes in the background disrupts the process of inhibitory marking of old items. PMID:25976299

  5. Progression of Patterns (POP): A Machine Classifier Algorithm to Identify Glaucoma Progression in Visual Fields

    PubMed Central

    Goldbaum, Michael H.; Lee, Intae; Jang, Giljin; Balasubramanian, Madhusudhanan; Sample, Pamela A.; Weinreb, Robert N.; Liebmann, Jeffrey M.; Girkin, Christopher A.; Anderson, Douglas R.; Zangwill, Linda M.; Fredette, Marie-Josee; Jung, Tzyy-Ping; Medeiros, Felipe A.; Bowd, Christopher

    2012-01-01

    Purpose. We evaluated Progression of Patterns (POP) for its ability to identify progression of glaucomatous visual field (VF) defects. Methods. POP uses variational Bayesian independent component mixture model (VIM), a machine learning classifier (MLC) developed previously. VIM separated Swedish Interactive Thresholding Algorithm (SITA) VFs from a set of 2,085 normal and glaucomatous eyes into nine axes (VF patterns): seven glaucomatous. Stable glaucoma was simulated in a second set of 55 patient eyes with five VFs each, collected within four weeks. A third set of 628 eyes with 4,186 VFs (mean ± SD of 6.7 ± 1.7 VFs over 4.0 ± 1.4 years) was tested for progression. Tested eyes were placed into suspect and glaucoma categories at baseline, based on VFs and disk stereoscopic photographs; a subset of eyes had stereophotographic evidence of progressive glaucomatous optic neuropathy (PGON). Each sequence of fields was projected along seven VIM glaucoma axes. Linear regression (LR) slopes generated from projections onto each axis yielded a degree of confidence (DOC) that there was progression. At 95% specificity, progression cutoffs were established for POP, visual field index (VFI), and mean deviation (MD). Guided progression analysis (GPA) was also compared. Results. POP identified a statistically similar number of eyes (P > 0.05) as progressing compared with VFI, MD, and GPA in suspects (3.8%, 2.7%, 5.6%, and 2.9%, respectively), and more eyes than GPA (P = 0.01) in glaucoma (16.0%, 15.3%, 12.0%, and 7.3%, respectively), and more eyes than GPA (P = 0.05) in PGON eyes (26.3%, 23.7%, 27.6%, and 14.5%, respectively). Conclusions. POP, with its display of DOC of progression and its identification of progressing VF defect pattern, adds to the information available to the clinician for detecting VF progression. PMID:22786913

  6. Visual Signals Vertically Extend the Perceptual Span in Searching a Text: A Gaze-Contingent Window Study

    ERIC Educational Resources Information Center

    Cauchard, Fabrice; Eyrolle, Helene; Cellier, Jean-Marie; Hyona, Jukka

    2010-01-01

    This study investigated the effect of visual signals on perceptual span in text search and the kinds of signal information that facilitate the search. Participants were asked to find answers to specific questions in chapter-length texts in either a normal or a window condition, where the text disappeared beyond a vertical 3 degrees gaze-contingent…

  7. Driven to Less Distraction: rTMS of the Right Parietal Cortex Reduces Attentional Capture in Visual Search

    Microsoft Academic Search

    John Hodsoll; Carmel Mevorach; Glyn W Humphreys

    2008-01-01

    In visual search, the presence of a highly salient color singleton can slow or facilitate search for a shape target depending on whether the singleton is a distractor or coincides with the target. This is consistent with an attentional shift (attentional capture) to the salient item. This attentional capture can be driven by bottom--up or top--down processes or both. We

  8. Beam angle optimization for intensity-modulated radiation therapy using a guided pattern search method

    NASA Astrophysics Data System (ADS)

    Rocha, Humberto; Dias, Joana M.; Ferreira, Brígida C.; Lopes, Maria C.

    2013-05-01

    Generally, the inverse planning of radiation therapy consists mainly of the fluence optimization. The beam angle optimization (BAO) in intensity-modulated radiation therapy (IMRT) consists of selecting appropriate radiation incidence directions and may influence the quality of the IMRT plans, both to enhance better organ sparing and to improve tumor coverage. However, in clinical practice, most of the time, beam directions continue to be manually selected by the treatment planner without objective and rigorous criteria. The goal of this paper is to introduce a novel approach that uses beam’s-eye-view dose ray tracing metrics within a pattern search method framework in the optimization of the highly non-convex BAO problem. Pattern search methods are derivative-free optimization methods that require a few function evaluations to progress and converge and have the ability to better avoid local entrapment. The pattern search method framework is composed of a search step and a poll step at each iteration. The poll step performs a local search in a mesh neighborhood and ensures the convergence to a local minimizer or stationary point. The search step provides the flexibility for a global search since it allows searches away from the neighborhood of the current iterate. Beam’s-eye-view dose metrics assign a score to each radiation beam direction and can be used within the pattern search framework furnishing a priori knowledge of the problem so that directions with larger dosimetric scores are tested first. A set of clinical cases of head-and-neck tumors treated at the Portuguese Institute of Oncology of Coimbra is used to discuss the potential of this approach in the optimization of the BAO problem.

  9. The impact of clinical indications on visual search behaviour in skeletal radiographs

    NASA Astrophysics Data System (ADS)

    Rutledge, A.; McEntee, M. F.; Rainford, L.; O'Grady, M.; McCarthy, K.; Butler, M. L.

    2011-03-01

    The hazards associated with ionizing radiation have been documented in the literature and therefore justifying the need for X-ray examinations has come to the forefront of the radiation safety debate in recent years1. International legislation states that the referrer is responsible for the provision of sufficient clinical information to enable the justification of the medical exposure. Clinical indications are a set of systematically developed statements to assist in accurate diagnosis and appropriate patient management2. In this study, the impact of clinical indications upon fracture detection for musculoskeletal radiographs is analyzed. A group of radiographers (n=6) interpreted musculoskeletal radiology cases (n=33) with and without clinical indications. Radiographic images were selected to represent common trauma presentations of extremities and pelvis. Detection of the fracture was measured using ROC methodology. An eyetracking device was employed to record radiographers search behavior by analysing distinct fixation points and search patterns, resulting in a greater level of insight and understanding into the influence of clinical indications on observers' interpretation of radiographs. The influence of clinical information on fracture detection and search patterns was assessed. Findings of this study demonstrate that the inclusion of clinical indications result in impressionable search behavior. Differences in eye tracking parameters were also noted. This study also attempts to uncover fundamental observer search strategies and behavior with and without clinical indications, thus providing a greater understanding and insight into the image interpretation process. Results of this study suggest that availability of adequate clinical data should be emphasized for interpreting trauma radiographs.

  10. Functional characterization and differential coactivation patterns of two cytoarchitectonic visual areas on the human posterior fusiform gyrus.

    PubMed

    Caspers, Julian; Zilles, Karl; Amunts, Katrin; Laird, Angela R; Fox, Peter T; Eickhoff, Simon B

    2014-06-01

    The ventral stream of the human extrastriate visual cortex shows a considerable functional heterogeneity from early visual processing (posterior) to higher, domain-specific processing (anterior). The fusiform gyrus hosts several of those "high-level" functional areas. We recently found a subdivision of the posterior fusiform gyrus on the microstructural level, that is, two distinct cytoarchitectonic areas, FG1 and FG2 (Caspers et al., Brain Structure & Function, 2013). To gain a first insight in the function of these two areas, here we studied their behavioral involvement and coactivation patterns by means of meta-analytic connectivity modeling based on the BrainMap database (www.brainmap.org), using probabilistic maps of these areas as seed regions. The coactivation patterns of the areas support the concept of a common involvement in a core network subserving different cognitive tasks, that is, object recognition, visual language perception, or visual attention. In addition, the analysis supports the previous cytoarchitectonic parcellation, indicating that FG1 appears as a transitional area between early and higher visual cortex and FG2 as a higher-order one. The latter area is furthermore lateralized, as it shows strong relations to the visual language processing system in the left hemisphere, while its right side is stronger associated with face selective regions. These findings indicate that functional lateralization of area FG2 relies on a different pattern of connectivity rather than side-specific cytoarchitectonic features. PMID:24038902

  11. A little bit of history repeating: Splitting up multiple-target visual searches decreases second-target miss errors.

    PubMed

    Cain, Matthew S; Biggs, Adam T; Darling, Elise F; Mitroff, Stephen R

    2014-06-01

    Visual searches with several targets in a display have been shown to be particularly prone to miss errors in both academic laboratory searches and professional searches such as radiology and baggage screening. Specifically, finding 1 target in a display can reduce the likelihood of detecting additional targets. This phenomenon was originally referred to as "satisfaction of search," but is referred to here as "subsequent search misses" (SSMs). SSM errors have been linked to a variety of causes, and recent evidence supports a working memory deficit wherein finding a target consumes working memory resources that would otherwise aid subsequent search for additional targets (Cain & Mitroff, 2013). The current study demonstrated that dividing 1 multiple-target search into several single-target searches, separated by three to five unrelated trials, effectively freed the working memory resources used by the found target and eliminated SSM errors. This effect was demonstrated with both university community participants and with professional visual searchers from the Transportation Security Administration, suggesting it may be a generally applicable technique for improving multiple-target visual search accuracy. PMID:24708353

  12. Gender Differences in Patterns of Searching the Web

    ERIC Educational Resources Information Center

    Roy, Marguerite; Chi, Michelene T. H.

    2003-01-01

    There has been a national call for increased use of computers and technology in schools. Currently, however, little is known about how students use and learn from these technologies. This study explores how eighth-grade students use the Web to search for, browse, and find information in response to a specific prompt (how mosquitoes find their…

  13. Interactions of visual odometry and landmark guidance during food search in honeybees.

    PubMed

    Vladusich, Tony; Hemmi, Jan M; Srinivasan, Mandyam V; Zeil, Jochen

    2005-11-01

    How do honeybees use visual odometry and goal-defining landmarks to guide food search? In one experiment, bees were trained to forage in an optic-flow-rich tunnel with a landmark positioned directly above the feeder. Subsequent food-search tests indicated that bees searched much more accurately when both odometric and landmark cues were available than when only odometry was available. When the two cue sources were set in conflict, by shifting the position of the landmark in the tunnel during test, bees overwhelmingly used landmark cues rather than odometry. In another experiment, odometric cues were removed by training and testing in axially striped tunnels. The data show that bees did not weight landmarks as highly as when odometric cues were available, tending to search in the vicinity of the landmark for shorter periods. A third experiment, in which bees were trained with odometry but without a landmark, showed that a novel landmark placed anywhere in the tunnel during testing prevented bees from searching beyond the landmark location. Two further experiments, involving training bees to relatively longer distances with a goal-defining landmark, produced similar results to the initial experiment. One caveat was that, with the removal of the familiar landmark, bees tended to overshoot the training location, relative to the case where bees were trained without a landmark. Taken together, the results suggest that bees assign appropriate significance to odometric and landmark cues in a more flexible and dynamic way than previously envisaged. PMID:16244171

  14. Are visual search procedures adapted to the nature of the script?

    PubMed

    Green, D W; Liow, S J; Tng, S K; Zielinski, S

    1996-05-01

    Letters are processed differently from other shapes in a visual search task where subjects have to decide whether or not a predesignated target symbol is present in a subsequently presented string of five such symbols. If the M-shaped letter search function, which relates correct reaction time to target position, reflects an efficient strategy used in word recognition, it should be produced by skilled readers of English who also read a logographic script. A cross-linguistic study of biscriptal Mandarin/English and monoscriptal English readers (Expt 1) provided evidence of the generality of a basic search strategy for alphabetic targets. Hand-of-response affected the search function in an asymmetric fashion for both groups of readers, and although case differences between target and string increased reaction times overall, the classic M-shaped function remained. In Expt 2, we used a within-subjects design and examined the extent to which biscriptal Mandarin/English readers produced different search functions for letters and logographs. Consistent with expectation, these readers showed an M-shaped function for letters but a more U-shaped function for logographs. Hand-of-response exerted a consistent effect for both types of material. Taken together, these experiments support the view that skilled readers develop script-specific procedures. PMID:8673360

  15. Visual Number Beats Abstract Numerical Magnitude: Format-dependent Representation of Arabic Digits and Dot Patterns in Human Parietal Cortex.

    PubMed

    Bulthé, Jessica; De Smedt, Bert; Op de Beeck, Hans P

    2015-07-01

    In numerical cognition, there is a well-known but contested hypothesis that proposes an abstract representation of numerical magnitude in human intraparietal sulcus (IPS). On the other hand, researchers of object cognition have suggested another hypothesis for brain activity in IPS during the processing of number, namely that this activity simply correlates with the number of visual objects or units that are perceived. We contrasted these two accounts by analyzing multivoxel activity patterns elicited by dot patterns and Arabic digits of different magnitudes while participants were explicitly processing the represented numerical magnitude. The activity pattern elicited by the digit "8" was more similar to the activity pattern elicited by one dot (with which the digit shares the number of visual units but not the magnitude) compared to the activity pattern elicited by eight dots, with which the digit shares the represented abstract numerical magnitude. A multivoxel pattern classifier trained to differentiate one dot from eight dots classified all Arabic digits in the one-dot pattern category, irrespective of the numerical magnitude symbolized by the digit. These results were consistently obtained for different digits in IPS, its subregions, and many other brain regions. As predicted from object cognition theories, the number of presented visual units forms the link between the parietal activation elicited by symbolic and nonsymbolic numbers. The current study is difficult to reconcile with the hypothesis that parietal activation elicited by numbers would reflect a format-independent representation of number. PMID:25633646

  16. A Convergence Analysis of Unconstrained and Bound Constrained Evolutionary Pattern Search

    SciTech Connect

    Hart, W.E.

    1999-04-22

    The authors present and analyze a class of evolutionary algorithms for unconstrained and bound constrained optimization on R{sup n}: evolutionary pattern search algorithms (EPSAs). EPSAs adaptively modify the step size of the mutation operator in response to the success of previous optimization steps. The design of EPSAs is inspired by recent analyses of pattern search methods. They show that EPSAs can be cast as stochastic pattern search methods, and they use this observation to prove that EpSAs have a probabilistic weak stationary point convergence theory. This work provides the first convergence analysis for a class of evolutionary algorithms that guarantees convergence almost surely to a stationary point of a nonconvex objective function.

  17. Superimposition of a cartoon program as an aid in recording pattern visual evoked potentials in children.

    PubMed

    Shors, T J; Eriksen, K J; Wright, K W

    1987-01-01

    Superimposition of a television program onto the black and white checkerboard stimulus used in performing the pattern visual evoked potential (P-VEP) has been found useful in testing adults and children. This study tested normal-vision children under two conditions: with the cartoon superimposition and with the standard black and white checkerboard. P100 amplitudes were decreased slightly with the superimposition, but the variability was not significantly different. Waveforms and latencies were not altered by the addition of the cartoon. The use of cartoon superimposition therefore can be helpful in maintaining attention during P-VEP testing in children, as long as the diminished amplitude characteristic is taken into account. PMID:3681608

  18. Intracellular Trafficking in Drosophila Visual System Development: A Basis for Pattern Formation Through Simple Mechanisms

    PubMed Central

    Chan, Chih-Chiang; Epstein, Daniel; Hiesinger, P. Robin

    2012-01-01

    Intracellular trafficking underlies cellular functions ranging from membrane remodeling to receptor activation. During multicellular organ development, these basic cell biological functions are required as both passive machinery and active signaling regulators. Exocytosis, endocytosis, and recycling of several key signaling receptors have long been known to actively regulate morphogenesis and pattern formation during Drosophila eye development. Hence, intracellular membrane trafficking not only sets the cell biological stage for receptor-mediated signaling but also actively controls signaling through spatiotemporally regulated receptor localization. In contrast to eye development, the role of intracellular trafficking for the establishment of the eye-to-brain connectivity map has only recently received more attention. It is still poorly understood how guidance receptors are spatiotemporally regulated to serve as meaningful synapse formation signals. Yet, the Drosophila visual system provides some of the most striking examples for the regulatory role of intracellular trafficking during multicellular organ development. In this review we will first highlight the experimental and conceptual advances that motivate the study of intracellular trafficking during Drosophila visual system development. We will then illuminate the development of the eye, the eye-to-brain connectivity map and the optic lobe from the perspective of cell biological dynamics. Finally, we provide a conceptual framework that seeks to explain how the interplay of simple genetically encoded intracellular trafficking events governs the seemingly complex cellular behaviors, which in turn determine the developmental product. PMID:21714102

  19. The interplay of attention and consciousness in visual search, attentional blink and working memory consolidation.

    PubMed

    Raffone, Antonino; Srinivasan, Narayanan; van Leeuwen, Cees

    2014-05-01

    Despite the acknowledged relationship between consciousness and attention, theories of the two have mostly been developed separately. Moreover, these theories have independently attempted to explain phenomena in which both are likely to interact, such as the attentional blink (AB) and working memory (WM) consolidation. Here, we make an effort to bridge the gap between, on the one hand, a theory of consciousness based on the notion of global workspace (GW) and, on the other, a synthesis of theories of visual attention. We offer a theory of attention and consciousness (TAC) that provides a unified neurocognitive account of several phenomena associated with visual search, AB and WM consolidation. TAC assumes multiple processing stages between early visual representation and conscious access, and extends the dynamics of the global neuronal workspace model to a visual attentional workspace (VAW). The VAW is controlled by executive routers, higher-order representations of executive operations in the GW, without the need for explicit saliency or priority maps. TAC leads to newly proposed mechanisms for illusory conjunctions, AB, inattentional blindness and WM capacity, and suggests neural correlates of phenomenal consciousness. Finally, the theory reconciles the all-or-none and graded perspectives on conscious representation. PMID:24639586

  20. The interplay of attention and consciousness in visual search, attentional blink and working memory consolidation

    PubMed Central

    Raffone, Antonino; Srinivasan, Narayanan; van Leeuwen, Cees

    2014-01-01

    Despite the acknowledged relationship between consciousness and attention, theories of the two have mostly been developed separately. Moreover, these theories have independently attempted to explain phenomena in which both are likely to interact, such as the attentional blink (AB) and working memory (WM) consolidation. Here, we make an effort to bridge the gap between, on the one hand, a theory of consciousness based on the notion of global workspace (GW) and, on the other, a synthesis of theories of visual attention. We offer a theory of attention and consciousness (TAC) that provides a unified neurocognitive account of several phenomena associated with visual search, AB and WM consolidation. TAC assumes multiple processing stages between early visual representation and conscious access, and extends the dynamics of the global neuronal workspace model to a visual attentional workspace (VAW). The VAW is controlled by executive routers, higher-order representations of executive operations in the GW, without the need for explicit saliency or priority maps. TAC leads to newly proposed mechanisms for illusory conjunctions, AB, inattentional blindness and WM capacity, and suggests neural correlates of phenomenal consciousness. Finally, the theory reconciles the all-or-none and graded perspectives on conscious representation. PMID:24639586

  1. Vector projectile imaging: time-resolved dynamic visualization of complex flow patterns.

    PubMed

    Yiu, Billy Y S; Lai, Simon S M; Yu, Alfred C H

    2014-09-01

    Achieving non-invasive, accurate and time-resolved imaging of vascular flow with spatiotemporal fluctuations is well acknowledged to be an ongoing challenge. In this article, we present a new ultrasound-based framework called vector projectile imaging (VPI) that can dynamically render complex flow patterns over an imaging view at millisecond time resolution. VPI is founded on three principles: (i) high-frame-rate broad-view data acquisition (based on steered plane wave firings); (ii) flow vector estimation derived from multi-angle Doppler analysis (coupled with data regularization and least-squares fitting); (iii) dynamic visualization of color-encoded vector projectiles (with flow speckles displayed as adjunct). Calibration results indicated that by using three transmit angles and three receive angles (-10°, 0°, +10° for both), VPI can consistently compute flow vectors in a multi-vessel phantom with three tubes positioned at different depths (1.5, 4, 6 cm), oriented at different angles (-10°, 0°, +10°) and of different sizes (dilated diameter: 2.2, 4.4 and 6.3 mm; steady flow rate: 2.5 mL/s). The practical merit of VPI was further illustrated through an anthropomorphic flow phantom investigation that considered both healthy and stenosed carotid bifurcation geometries. For the healthy bifurcation with 1.2-Hz carotid flow pulses, VPI was able to render multi-directional and spatiotemporally varying flow patterns (using a nominal frame rate of 416 fps or 2.4-ms time resolution). In the case of stenosed bifurcations (50% eccentric narrowing), VPI enabled dynamic visualization of flow jet and recirculation zones. These findings suggest that VPI holds promise as a new tool for complex flow analysis. PMID:24972498

  2. Multi-voxel pattern analysis of selective representation of visual working memory in ventral temporal and occipital regions.

    PubMed

    Han, Xufeng; Berg, Alexander C; Oh, Hwamee; Samaras, Dimitris; Leung, Hoi-Chung

    2013-06-01

    While previous results from univariate analysis showed that the activity level of the parahippocampal gyrus (PHG) but not the fusiform gyrus (FG) reflects selective maintenance of the cued picture category, present results from multi-voxel pattern analysis (MVPA) showed that the spatial response patterns of both regions can be used to differentiate the selected picture category in working memory. The ventral temporal and occipital areas including the PHG and FG have been shown to be specialized in perceiving and processing different kinds of visual information, though their role in the representation of visual working memory remains unclear. To test whether the PHG and FG show spatial response patterns that reflect selective maintenance of task-relevant visual working memory in comparison with other posterior association regions, we reanalyzed data from a previous fMRI study of visual working memory with a cue inserted during the delay period of a delayed recognition task. Classification of FG and PHG activation patterns for the selected category (face or scene) during the cue phase was well above chance using classifiers trained with fMRI data from the cue or probe phase. Classification of activity in other temporal and occipital regions for the cued picture category during the cue phase was relatively less consistent even though classification of their activity during the probe recognition was comparable with the FG and PHG. In sum, these findings suggest that the FG and PHG carry information relevant to the cued visual category, and their spatial activation patterns during selective maintenance seem to match those during visual recognition. PMID:23380167

  3. Acute effects of nicotine on visual search tasks in young adult smokers

    Microsoft Academic Search

    Nicola Rycroft; Jennifer M. Rusted; Samuel B. Hutton

    2005-01-01

    Rationale  Nicotine is known to improve performance on tests involving sustained attention and recent research suggests that nicotine\\u000a may also improve performance on tests involving the strategic allocation of attention and working memory.\\u000a \\u000a \\u000a \\u000a Objectives  We used measures of accuracy and response latency combined with eye-tracking techniques to examine the effects of nicotine\\u000a on visual search tasks.\\u000a \\u000a \\u000a \\u000a Methods  In experiment 1 smokers and non-smokers

  4. Modeling peripheral visual acuity enables discovery of gaze strategies at multiple time scales during natural scene search

    PubMed Central

    Ramkumar, Pavan; Fernandes, Hugo; Kording, Konrad; Segraves, Mark

    2015-01-01

    Like humans, monkeys make saccades nearly three times a second. To understand the factors guiding this frequent decision, computational models of vision attempt to predict fixation locations using bottom-up visual features and top-down goals. How do the relative influences of these factors evolve over multiple time scales? Here we analyzed visual features at fixations using a retinal transform that provides realistic visual acuity by suitably degrading visual information in the periphery. In a task in which monkeys searched for a Gabor target in natural scenes, we characterized the relative importance of bottom-up and task-relevant influences by decoding fixated from nonfixated image patches based on visual features. At fast time scales, we found that search strategies can vary over the course of a single trial, with locations of higher saliency, target-similarity, edge–energy, and orientedness looked at later on in the trial. At slow time scales, we found that search strategies can be refined over several weeks of practice, and the influence of target orientation was significant only in the latter of two search tasks. Critically, these results were not observed without applying the retinal transform. Our results suggest that saccade-guidance strategies become apparent only when models take into account degraded visual representation in the periphery. PMID:25814545

  5. Incidental learning speeds visual search by lowering response thresholds, not by improving efficiency: Evidence from eye movements

    PubMed Central

    Hout, Michael C.; Goldinger, Stephen D.

    2011-01-01

    When observers search for a target object, they incidentally learn the identities and locations of “background” objects in the same display. This learning can facilitate search performance, eliciting faster reaction times for repeated displays (Hout & Goldinger, 2010). Despite these findings, visual search has been successfully modeled using architectures that maintain no history of attentional deployments; they are amnesic (e.g., Guided Search Theory; Wolfe, 2007). In the current study, we asked two questions: 1) under what conditions does such incidental learning occur? And 2) what does viewing behavior reveal about the efficiency of attentional deployments over time? In two experiments, we tracked eye movements during repeated visual search, and we tested incidental memory for repeated non-target objects. Across conditions, the consistency of search sets and spatial layouts were manipulated to assess their respective contributions to learning. Using viewing behavior, we contrasted three potential accounts for faster searching with experience. The results indicate that learning does not result in faster object identification or greater search efficiency. Instead, familiar search arrays appear to allow faster resolution of search decisions, whether targets are present or absent. PMID:21574743

  6. Neural responses to visual scenes reveals inconsistencies between fMRI adaptation and multivoxel pattern analysis.

    PubMed

    Epstein, Russell A; Morgan, Lindsay K

    2012-03-01

    Human observers can recognize real-world visual scenes with great efficiency. Cortical regions such as the parahippocampal place area (PPA) and retrosplenial complex (RSC) have been implicated in scene recognition, but the specific representations supported by these regions are largely unknown. We used functional magnetic resonance imaging adaptation (fMRIa) and multi-voxel pattern analysis (MVPA) to explore this issue, focusing on whether the PPA and RSC represent scenes in terms of general categories, or as specific scenic exemplars. Subjects were scanned while viewing images drawn from 10 outdoor scene categories in two scan runs and images of 10 familiar landmarks from their home college campus in two scan runs. Analyses of multi-voxel patterns revealed that the PPA and RSC encoded both category and landmark information, with a slight advantage for landmark coding in RSC. fMRIa, on the other hand, revealed a very different picture: both PPA and RSC adapted when landmark information was repeated, but category adaptation was only observed in a small subregion of the left PPA. These inconsistencies between the MVPA and fMRIa data suggests that these two techniques interrogate different aspects of the neuronal code. We propose three hypotheses about the mechanisms that might underlie adaptation and multi-voxel signals. PMID:22001314

  7. Iterative Integration of Visual Insights during Scalable Patent Search and Analysis.

    PubMed

    Koch, Steffen; Bosch, Harald; Giereth, Mark; Ertl, Thomas

    2010-06-01

    Patents are of growing importance in current economic markets. Analyzing patent information has therefore become a common task for many interest groups. As a prerequisite for patent analysis, extensive search for relevant patent information is essential. Unfortunately, the complexity of patent material inhibits a straightforward retrieval of all relevant patent documents and leads to iterative, time-consuming approaches in practice. Already the amount of patent data to be analyzed poses challenges with respect to scalability. Further scalability issues arise concerning the diversity of users and the large variety of analysis tasks. With 'PatViz', a system for interactive analysis of patent information has been developed addressing scalability at various levels. PatViz provides a visual environment allowing for interactive reintegration of insights into subsequent search iterations, thereby bridging the gap between search and analytic processes. Because of its extensibility, we expect that the approach we have taken can be employed in different problem domains that require high quality of search results regarding their completeness. PMID:20530812

  8. Distributed Patterns of Activity in Sensory Cortex Reflect the Precision of Multiple Items Maintained in Visual Short-Term Memory

    PubMed Central

    Emrich, Stephen M.; Riggall, Adam C.; LaRocque, Joshua J.; Postle, Bradley R.

    2013-01-01

    Traditionally, load sensitivity of sustained, elevated activity has been taken as an index of storage for a limited number of items in visual short-term memory (VSTM). Recently, studies have demonstrated that the contents of a single item held in VSTM can be decoded from early visual cortex, despite the fact that these areas do not exhibit elevated, sustained activity. It is unknown, however, whether the patterns of neural activity decoded from sensory cortex change as a function of load, as one would expect from a region storing multiple representations. Here, we use multi-voxel pattern analysis (MVPA) to examine the neural representations of VSTM in humans across multiple memory loads. In an important extension of previous findings, our results demonstrate that the contents of VSTM can be decoded from areas that exhibit a transient response to visual stimuli, but not from regions that exhibit elevated, sustained load-sensitive delay-period activity. Moreover, the neural information present in these transiently activated areas decreases significantly with increasing load, indicating load sensitivity of the patterns of activity that support VSTM maintenance. Importantly, the decrease in classification performance as a function of load correlates with within-subject changes in mnemonic resolution. These findings indicate that distributed patterns of neural activity in putatively sensory visual cortex support the representation and precision of information in VSTM. PMID:23575849

  9. Visual Analysis of Historic Hotel Visitation Patterns Chris Weaver David Fyfe Anthony Robinson Deryck Holdsworth Donna Peuquet

    E-print Network

    Klippel, Alexander

    collection and plans to expand exploration to include historic weather records and railroad schedules views, travel pattern analysis. Index Terms: D.2.2 [Software Engineering]: Design Tools and Techniques of integrated software for rapid con- struction of visual data analysis tools is a recent focus of research

  10. Static Magnetic Field Stimulation over the Visual Cortex Increases Alpha Oscillations and Slows Visual Search in Humans.

    PubMed

    Gonzalez-Rosa, Javier J; Soto-Leon, Vanesa; Real, Pablo; Carrasco-Lopez, Carmen; Foffani, Guglielmo; Strange, Bryan A; Oliviero, Antonio

    2015-06-17

    Transcranial static magnetic field stimulation (tSMS) was recently introduced as a promising tool to modulate human cerebral excitability in a noninvasive and portable way. However, a demonstration that static magnetic fields can influence human brain activity and behavior is currently lacking, despite evidence that static magnetic fields interfere with neuronal function in animals. Here we show that transcranial application of a static magnetic field (120-200 mT at 2-3 cm from the magnet surface) over the human occiput produces a focal increase in the power of alpha oscillations in underlying cortex. Critically, this neurophysiological effect of tSMS is paralleled by slowed performance in a visual search task, selectively for the most difficult target detection trials. The typical relationship between prestimulus alpha power over posterior cortical areas and reaction time (RT) to targets during tSMS is altered such that tSMS-dependent increases in alpha power are associated with longer RTs for difficult, but not easy, target detection trials. Our results directly demonstrate that a powerful magnet placed on the scalp modulates normal brain activity and induces behavioral changes in humans. PMID:26085640

  11. Right fusiform response patterns reflect visual object identity rather than semantic similarity.

    PubMed

    Bruffaerts, Rose; Dupont, Patrick; De Grauwe, Sophie; Peeters, Ronald; De Deyne, Simon; Storms, Gerrit; Vandenberghe, Rik

    2013-12-01

    We previously reported the neuropsychological consequences of a lesion confined to the middle and posterior part of the right fusiform gyrus (case JA) causing a partial loss of knowledge of visual attributes of concrete entities in the absence of category-selectivity (animate versus inanimate). We interpreted this in the context of a two-step model that distinguishes structural description knowledge from associative-semantic processing and implicated the lesioned area in the former process. To test this hypothesis in the intact brain, multi-voxel pattern analysis was used in a series of event-related fMRI studies in a total of 46 healthy subjects. We predicted that activity patterns in this region would be determined by the identity of rather than the conceptual similarity between concrete entities. In a prior behavioral experiment features were generated for each entity by more than 1000 subjects. Based on a hierarchical clustering analysis the entities were organised into 3 semantic clusters (musical instruments, vehicles, tools). Entities were presented as words or pictures. With foveal presentation of pictures, cosine similarity between fMRI response patterns in right fusiform cortex appeared to reflect both the identity of and the semantic similarity between the entities. No such effects were found for words in this region. The effect of object identity was invariant for location, scaling, orientation axis and color (grayscale versus color). It also persisted for different exemplars referring to a same concrete entity. The apparent semantic similarity effect however was not invariant. This study provides further support for a neurobiological distinction between structural description knowledge and processing of semantic relationships and confirms the role of right mid-posterior fusiform cortex in the former process, in accordance with previous lesion evidence. PMID:23811413

  12. Geometric optimization of yield-line patterns using a direct search method

    Microsoft Academic Search

    A. C. A. Ramsay; D. Johnson

    1997-01-01

    A class of problems in the geometric optimization of yield-line patterns, for which the currently advocatedconjugate gradient andsequential linear programming geometric optimization algorithms fail is investigated. TheHooke-Jeeves direct search method is implemented and is demonstrated to solve such problems robustly.

  13. APPSPACK 4.0 : asynchronous parallel pattern search for derivative-free optimization

    Microsoft Academic Search

    Genetha Anne Gray; Tamara Gibson Kolda

    2004-01-01

    APPSPACK is software for solving unconstrained and bound constrained optimization problems. It implements an asynchronous parallel pattern search method that has been specifically designed for problems characterized by expensive function evaluations. Using APPSPACK to solve optimization problems has several advantages: No derivative information is needed; the procedure for evaluating the objective function can be executed via a separate program or

  14. Particle Swarm with graphics hardware acceleration and local pattern search on bound constrained problems

    Microsoft Academic Search

    Weihang Zhu; James Curry

    2009-01-01

    This paper presents a particle swarm - pattern search optimization (PS2) algorithm with graphics hardware acceleration for bound constrained nonlinear optimization problems. The objective of this study is to determine the effectiveness of using graphics processing units (GPU) as a hardware platform for particle swarm optimization (PSO). GPU, the common graphics hardware which can be found in many personal computers,

  15. Multimodal neuroimaging evidence linking memory and attention systems during visual search cued by context.

    PubMed

    Kasper, Ryan W; Grafton, Scott T; Eckstein, Miguel P; Giesbrecht, Barry

    2015-03-01

    Visual search can be facilitated by the learning of spatial configurations that predict the location of a target among distractors. Neuropsychological and functional magnetic resonance imaging (fMRI) evidence implicates the medial temporal lobe (MTL) memory system in this contextual cueing effect, and electroencephalography (EEG) studies have identified the involvement of visual cortical regions related to attention. This work investigated two questions: (1) how memory and attention systems are related in contextual cueing; and (2) how these systems are involved in both short- and long-term contextual learning. In one session, EEG and fMRI data were acquired simultaneously in a contextual cueing task. In a second session conducted 1 week later, EEG data were recorded in isolation. The fMRI results revealed MTL contextual modulations that were correlated with short- and long-term behavioral context enhancements and attention-related effects measured with EEG. An fMRI-seeded EEG source analysis revealed that the MTL contributed the most variance to the variability in the attention enhancements measured with EEG. These results support the notion that memory and attention systems interact to facilitate search when spatial context is implicitly learned. PMID:25586959

  16. Temporal relationships between eye fixations and manual reactions in visual search.

    PubMed

    Greene, H H

    1999-03-01

    Observers freely searched for, and manually responded to, the presence of a target in multistimulus displays. The stimuli were presented on a cinema screen such that each display subtended a large visual angle to encourage the use of eye movements. Times taken to initially fixate the target (T1Fs) were compared to manual response times (MRTs). The results of two experiments were qualitatively similar, despite different levels of difficulty between them. MRTs were a linear function of T1Fs, but only when fixations did not occur very early after the onset of the stimulus display. When fixations were made very soon after the onset of the display, T1Fs were independent of MRTs. The findings were described within the framework of a one-way synchronization model which was modified to accommodate attention effects in visual search. Finally, the methodology provides a novel means of quantifying the contributions of eye movements to manual acknowledgements in real-world vision-guided tasks. PMID:10100456

  17. Timing of saccadic eye movements during visual search for multiple targets.

    PubMed

    Wu, Chia-Chien; Kowler, Eileen

    2013-01-01

    Visual search requires sequences of saccades. Many studies have focused on spatial aspects of saccadic decisions, while relatively few (e.g., Hooge & Erkelens, 1999) consider timing. We studied saccadic timing during search for targets (thin circles containing tilted lines) located among nontargets (thicker circles). Tasks required either (a) estimating the mean tilt of the lines, or (b) looking at targets without a concurrent psychophysical task. The visual similarity of targets and nontargets affected both the probability of hitting a target and the saccade rate in both tasks. Saccadic timing also depended on immediate conditions, specifically, (a) the type of currently fixated location (dwell time was longer on targets than nontargets), (b) the type of goal (dwell time was shorter prior to saccades that hit targets), and (c) the ordinal position of the saccade in the sequence. The results show that timing decisions take into account the difficulty of finding targets, as well as the cost of delays. Timing strategies may be a compromise between the attempt to find and locate targets, or other suitable landing locations, using eccentric vision (at the cost of increased dwell times) versus a strategy of exploring less selectively at a rapid rate. PMID:24049045

  18. Separability of abstract-category and specific-exemplar visual object subsystems: evidence from fMRI pattern analysis.

    PubMed

    McMenamin, Brenton W; Deason, Rebecca G; Steele, Vaughn R; Koutstaal, Wilma; Marsolek, Chad J

    2015-02-01

    Previous research indicates that dissociable neural subsystems underlie abstract-category (AC) recognition and priming of objects (e.g., cat, piano) and specific-exemplar (SE) recognition and priming of objects (e.g., a calico cat, a different calico cat, a grand piano, etc.). However, the degree of separability between these subsystems is not known, despite the importance of this issue for assessing relevant theories. Visual object representations are widely distributed in visual cortex, thus a multivariate pattern analysis (MVPA) approach to analyzing functional magnetic resonance imaging (fMRI) data may be critical for assessing the separability of different kinds of visual object processing. Here we examined the neural representations of visual object categories and visual object exemplars using multi-voxel pattern analyses of brain activity elicited in visual object processing areas during a repetition-priming task. In the encoding phase, participants viewed visual objects and the printed names of other objects. In the subsequent test phase, participants identified objects that were either same-exemplar primed, different-exemplar primed, word-primed, or unprimed. In visual object processing areas, classifiers were trained to distinguish same-exemplar primed objects from word-primed objects. Then, the abilities of these classifiers to discriminate different-exemplar primed objects and word-primed objects (reflecting AC priming) and to discriminate same-exemplar primed objects and different-exemplar primed objects (reflecting SE priming) was assessed. Results indicated that (a) repetition priming in occipital-temporal regions is organized asymmetrically, such that AC priming is more prevalent in the left hemisphere and SE priming is more prevalent in the right hemisphere, and (b) AC and SE subsystems are weakly modular, not strongly modular or unified. PMID:25528436

  19. Shared space, separate processes: neural activation patterns for auditory description and visual object naming in healthy adults

    PubMed Central

    Hamberger, Marla J.; Habeck, Christian G.; Pantazatos, Spiro P.; Williams, Alicia C.; Hirsch, Joy

    2014-01-01

    Historically, both clinicians and cognitive scientists have used visual object naming measures to study naming, and lesion-type studies have implicated the left posterior, temporo-parietal region as a critical component of naming circuitry. However, recent results from behavioral and cortical stimulation studies using auditory description naming as well as visual object naming in left temporal lobe epilepsy patients suggest that discrete sites in anterior temporal cortex are critical for description naming, whereas posterior temporal regions mediate both visual object naming and description naming. To determine whether this task specificity reflects normal cerebral organization and processing, 13 healthy adults performed description naming and visual naming during functional neuroimaging. In addition to standard univariate analysis, multivariate, Ordinal Trend Analysis examined the network character of the regions involved in task-specific naming. Univariate analysis indicated posterior temporal activation for both visual naming and description naming, whereas multivariate analysis revealed broader networks for both tasks, with both overlapping and task-specific regions, as well as task related differences in the way the tasks utilized common regions. Additionally, multivariate analysis revealed unique, task-specific, regionally covarying activation patterns that were strikingly consistent in all 13 subjects for visual naming and 12/13 subjects for description naming. Results suggest a common neural substrate, yet differentiable neural processes underlying visual naming and description naming in neurologically intact individuals. These findings support the use of both types of tasks for clinical assessment, and may have application in the treatment of neurologically based naming deficits. PMID:23918095

  20. Ideal and visual-search observers: accounting for anatomical noise in search tasks with planar nuclear imaging

    NASA Astrophysics Data System (ADS)

    Sen, Anando; Gifford, Howard C.

    2015-03-01

    Model observers have frequently been used for hardware optimization of imaging systems. For model observers to reliably mimic human performance it is important to account for the sources of variations in the images. Detection-localization tasks are complicated by anatomical noise present in the images. Several scanning observers have been proposed for such tasks. The most popular of these, the channelized Hotelling observer (CHO) incorporates anatomical variations through covariance matrices. We propose the visual-search (VS) observer as an alternative to the CHO to account for anatomical noise. The VS observer is a two-step process which first identifies suspicious tumor candidates and then performs a detailed analysis on them. The identification of suspicious candidates (search) implicitly accounts for anatomical noise. In this study we present a comparison of these two observers with human observers. The application considered is collimator optimization for planar nuclear imaging. Both observers show similar trends in performance with the VS observer slightly closer to human performance.

  1. 3D PATTERN OF BRAIN ABNORMALITIES IN WILLIAMS SYNDROME VISUALIZED USING TENSOR-BASED MORPHOMETRY

    PubMed Central

    Chiang, Ming-Chang; Reiss, Allan L.; Lee, Agatha D.; Bellugi, Ursula; Galaburda, Albert M.; Korenberg, Julie R.; Mills, Debra L.; Toga, Arthur W.; Thompson, Paul M.

    2009-01-01

    Williams syndrome (WS) is a neurodevelopmental disorder associated with deletion of ~20 contiguous genes in chromosome band 7q11.23. Individuals with WS exhibit mild to moderate mental retardation, but are relatively more proficient in specific language and musical abilities. We used tensor-based morphometry (TBM) to visualize the complex pattern of gray/white matter reductions in WS, based on fluid registration of structural brain images. Methods 3D T1-weighted brain MRIs of 41 WS subjects (age: 29.2±9.2SD years; 23F/18M) and 39 age-matched healthy controls (age: 27.5±7.4 years; 23F/16M) were fluidly registered to a minimum deformation target. Fine-scale volumetric differences were mapped between diagnostic groups. Local regions were identified where regional structure volumes were associated with diagnosis, and with intelligence quotient (IQ) scores. Brain asymmetry was also mapped and compared between diagnostic groups. Results WS subjects exhibited widely distributed brain volume reductions (~10–15% reduction; P < 0.0002, permutation test). After adjusting for total brain volume, the frontal lobes, anterior cingulate, superior temporal gyrus, amygdala, fusiform gyrus and cerebellum were found to be relatively preserved in WS, but parietal and occipital lobes, thalamus and basal ganglia, and midbrain were disproportionally decreased in volume (P < 0.0002). These regional volumes also correlated positively with performance IQ in adult WS subjects (age ? 30 years, P = 0.038). Conclusion TBM facilitates 3D visualization of brain volume reductions in WS. Reduced parietal/occipital volumes may be associated with visuospatial deficits in WS. By contrast, frontal lobes, amygdala, and cingulate gyrus are relatively preserved or even enlarged, consistent with unusual affect regulation and language production in WS. PMID:17512756

  2. Autism spectrum disorder, but not amygdala lesions, impairs social attention in visual search.

    PubMed

    Wang, Shuo; Xu, Juan; Jiang, Ming; Zhao, Qi; Hurlemann, Rene; Adolphs, Ralph

    2014-10-01

    People with autism spectrum disorders (ASD) have pervasive impairments in social interactions, a diagnostic component that may have its roots in atypical social motivation and attention. One of the brain structures implicated in the social abnormalities seen in ASD is the amygdala. To further characterize the impairment of people with ASD in social attention, and to explore the possible role of the amygdala, we employed a series of visual search tasks with both social (faces and people with different postures, emotions, ages, and genders) and non-social stimuli (e.g., electronics, food, and utensils). We first conducted trial-wise analyses of fixation properties and elucidated visual search mechanisms. We found that an attentional mechanism of initial orientation could explain the detection advantage of non-social targets. We then zoomed into fixation-wise analyses. We defined target-relevant effects as the difference in the percentage of fixations that fell on target-congruent vs. target-incongruent items in the array. In Experiment 1, we tested 8 high-functioning adults with ASD, 3 adults with focal bilateral amygdala lesions, and 19 controls. Controls rapidly oriented to target-congruent items and showed a strong and sustained preference for fixating them. Strikingly, people with ASD oriented significantly less and more slowly to target-congruent items, an attentional deficit especially with social targets. By contrast, patients with amygdala lesions performed indistinguishably from controls. In Experiment 2, we recruited a different sample of 13 people with ASD and 8 healthy controls, and tested them on the same search arrays but with all array items equalized for low-level saliency. The results replicated those of Experiment 1. In Experiment 3, we recruited 13 people with ASD, 8 healthy controls, 3 amygdala lesion patients and another group of 11 controls and tested them on a simpler array. Here our group effect for ASD strongly diminished and all four subject groups showed similar target-relevant effects. These findings argue for an attentional deficit in ASD that is disproportionate for social stimuli, cannot be explained by low-level visual properties of the stimuli, and is more severe with high-load top-down task demands. Furthermore, this deficit appears to be independent of the amygdala, and not evident from general social bias independent of the target-directed search. PMID:25218953

  3. Autism spectrum disorder, but not amygdala lesions, impairs social attention in visual search

    PubMed Central

    Wang, Shuo; Xu, Juan; Jiang, Ming; Zhao, Qi; Hurlemann, Rene; Adolphs, Ralph

    2015-01-01

    People with autism spectrum disorders (ASD) have pervasive impairments in social interactions, a diagnostic component that may have its roots in atypical social motivation and attention. One of the brain structures implicated in the social abnormalities seen in ASD is the amygdala. To further characterize the impairment of people with ASD in social attention, and to explore the possible role of the amygdala, we employed a series of visual search tasks with both social (faces and people with different postures, emotions, ages, and genders) and non-social stimuli (e.g., electronics, food, and utensils). We first conducted trial-wise analyses of fixation properties and elucidated visual search mechanisms. We found that an attentional mechanism of initial orientation could explain the detection advantage of non-social targets. We then zoomed into fixation-wise analyses. We defined target-relevant effects as the difference in the percentage of fixations that fell on target-congruent vs. target-incongruent items in the array. In Experiment 1, we tested 8 high-functioning adults with ASD, 3 adults with focal bilateral amygdala lesions, and 19 controls. Controls rapidly oriented to target-congruent items and showed a strong and sustained preference for fixating them. Strikingly, people with ASD oriented significantly less and more slowly to target-congruent items, an attentional deficit especially with social targets. By contrast, patients with amygdala lesions performed indistinguishably from controls. In Experiment 2, we recruited a different sample of 13 people with ASD and 8 healthy controls, and tested them on the same search arrays but with all array items equalized for low-level saliency. The results replicated those of Experiment 1. In Experiment 3, we recruited 13 people with ASD, 8 healthy controls, 3 amygdala lesion patients and another group of 11 controls and tested them on a simpler array. Here our group effect for ASD strongly diminished and all four subject groups showed similar target-relevant effects. These findings argue for an attentional deficit in ASD that is disproportionate for social stimuli, cannot be explained by low-level visual properties of the stimuli, and is more severe with high-load top-down task demands. Furthermore, this deficit appears to be independent of the amygdala, and not evident from general social bias independent of the target-directed search. PMID:25218953

  4. Visual Search Strategies of Soccer Players Executing a Power vs. Placement Penalty Kick

    PubMed Central

    Timmis, Matthew A.; Turner, Kieran; van Paridon, Kjell N.

    2014-01-01

    Introduction When taking a soccer penalty kick, there are two distinct kicking techniques that can be adopted; a ‘power’ penalty or a ‘placement’ penalty. The current study investigated how the type of penalty kick being taken affected the kicker’s visual search strategy and where the ball hit the goal (end ball location). Method Wearing a portable eye tracker, 12 university footballers executed 2 power and placement penalty kicks, indoors, both with and without the presence of a goalkeeper. Video cameras were used to determine initial ball velocity and end ball location. Results When taking the power penalty, the football was kicked significantly harder and more centrally in the goal compared to the placement penalty. During the power penalty, players fixated on the football for longer and more often at the goalkeeper (and by implication the middle of the goal), whereas in the placement penalty, fixated longer at the goal, specifically the edges. Findings remained consistent irrespective of goalkeeper presence. Discussion/conclusion Findings indicate differences in visual search strategy and end ball location as a function of type of penalty kick. When taking the placement penalty, players fixated and kicked the football to the edges of the goal in an attempt to direct the ball to an area that the goalkeeper would have difficulty reaching and saving. Fixating significantly longer on the football when taking the power compared to placement penalty indicates a greater importance of obtaining visual information from the football. This can be attributed to ensuring accurate foot-to-ball contact and subsequent generation of ball velocity. Aligning gaze and kicking the football centrally in the goal when executing the power compared to placement penalty may have been a strategy to reduce the risk of kicking wide of the goal altogether. PMID:25517405

  5. Virtual evolution for visual search in natural images results in behavioral receptive fields with inhibitory surrounds.

    PubMed

    Zhang, Sheng; Abbey, Craig K; Eckstein, Miguel P

    2009-01-01

    The neural mechanisms driving perception and saccades during search use information about the target but are also based on an inhibitory surround not present in the target luminance profile (e.g., Eckstein et al., 2007). Here, we ask whether these inhibitory surrounds might reflect a strategy that the brain has adapted to optimize the search for targets in natural scenes. To test this hypothesis, we sought to estimate the best linear template (behavioral receptive field), built from linear combinations of Gabor channels representing V1 simple cells in search for an additive Gaussian target embedded in natural images. Statistically nonstationary and non-Gaussian properties of natural scenes preclude calculation of the best linear template from analytic expressions and require an iterative optimization method such as a virtual evolution via a genetic algorithm. Evolved linear receptive fields built from linear combinations of Gabor functions include substantial inhibitory surround, larger than those found in humans performing target search in white noise. The inhibitory surrounds were robust to changes in the contrast of the signal, generalized to a larger calibrated natural image data set, and tasks in which the signal occluded other objects in the image. We show that channel nonlinearities can have strong effects on the observed linear behavioral receptive field but preserve the inhibitory surrounds. Together, the results suggest that the apparent suboptimality of inhibitory surrounds in human behavioral receptive fields when searching for a target in white noise might reflect a strategy to optimize detection of signals in natural scenes. Finally, we contend that optimized linear detection of spatially compact signals in natural images might be a new possible hypothesis, distinct from decorrelation of visual input and sparse representations (e.g., Graham et al., 2006), to explain the evolution of center-surround organization of receptive fields in early vision. PMID:19278570

  6. Neurophysiological correlates of relatively enhanced local visual search in autistic adolescents.

    PubMed

    Manjaly, Zina M; Bruning, Nicole; Neufang, Susanne; Stephan, Klaas E; Brieber, Sarah; Marshall, John C; Kamp-Becker, Inge; Remschmidt, Helmut; Herpertz-Dahlmann, Beate; Konrad, Kerstin; Fink, Gereon R

    2007-03-01

    Previous studies found normal or even superior performance of autistic patients on visuospatial tasks requiring local search, like the Embedded Figures Task (EFT). A well-known interpretation of this is "weak central coherence", i.e. autistic patients may show a reduced general ability to process information in its context and may therefore have a tendency to favour local over global aspects of information processing. An alternative view is that the local processing advantage in the EFT may result from a relative amplification of early perceptual processes which boosts processing of local stimulus properties but does not affect processing of global context. This study used functional magnetic resonance imaging (fMRI) in 12 autistic adolescents (9 Asperger and 3 high-functioning autistic patients) and 12 matched controls to help distinguish, on neurophysiological grounds, between these two accounts of EFT performance in autistic patients. Behaviourally, we found autistic individuals to be unimpaired during the EFT while they were significantly worse at performing a closely matched control task with minimal local search requirements. The fMRI results showed that activations specific for the local search aspects of the EFT were left-lateralised in parietal and premotor areas for the control group (as previously demonstrated for adults), whereas for the patients these activations were found in right primary visual cortex and bilateral extrastriate areas. These results suggest that enhanced local processing in early visual areas, as opposed to impaired processing of global context, is characteristic for performance of the EFT by autistic patients. PMID:17240169

  7. Cross-trial priming in visual search for singleton conjunction targets: Role of repeated target and distractor features

    Microsoft Academic Search

    Thomas Geyer; Hermann J. Müller; Joseph Krummenacher

    2006-01-01

    Kristjánsson, Wang, and Nakayama (2002) demonstrated that visual search for conjunctively defined targets can be substantially\\u000a expedited (“primed”) when target and distractor features are repeated on consecutive trials. Two experiments were conducted\\u000a to examine whether the search response time (RT) facilitation on target-present trials results from repetition of target-defining\\u000a features, distractor features, or both. The experiments used a multiple conjunctive

  8. Effects of menu structure and touch screen scrolling style on the variability of glance durations during in-vehicle visual search tasks

    Microsoft Academic Search

    Tuomo Kujala; Pertti Saariluoma

    2011-01-01

    The effects of alternative navigation device display features on drivers' visual sampling efficiency while searching forpoints of interest were studied in two driving simulation experiments with 40 participants. Given that the number of display items was sufficient, display features that facilitate resumption of visual search following interruptions were expected to lead to more consistent in-vehicle glance durations. As predicted, compared

  9. Effect of sevoflurane concentration on visual evoked potentials with pattern stimulation in dogs

    PubMed Central

    ITO, Yosuke; MAEHARA, Seiya; ITOH, Yoshiki; HAYASHI, Miri; KUBO, Akira; ITAMI, Takaharu; ISHIZUKA, Tomohito; TAMURA, Jun; YAMASHITA, Kazuto

    2014-01-01

    The purpose of this study was to investigate the effects of sevoflurane concentration on canine visual evoked potentials with pattern stimulation (P-VEPs). Six clinically normal laboratory-beagle dogs were used. The minimum alveolar concentration (MAC) of sevoflurane was detected from all subjects by tail clamp method. The refractive power of the right eyes of all subjects was corrected to ?2 diopters after skiascopy. For P-VEP recording, the recording and reference electrode were positioned at inion and nasion, respectively, and the earth electrode was positioned on the inner surface. To grasp the state of CNS suppression objectively, the bispectral index (BIS) value was used. The stimulus pattern size and distance for VEP recording were constant, 50.3 arc-min and 50 cm, respectively. P-VEPs and BIS values were recorded under sevoflurane in oxygen inhalational anesthesia at 0.5, 1.0, 1.5, 2.0, 2.5 and 2.75 sevoflurane MAC. For analysis of P-VEP, the P100 implicit time and N75-P100 amplitude were estimated. P-VEPs were detected at 0.5 to 1.5 MAC in all dogs, and disappeared at 2.0 MAC in four dogs and at 2.5 and 2.75 MAC in one dog each. The BIS value decreased with increasing sevoflurane MAC, and burst suppression began to appear from 1.5 MAC. There was no significant change in P100 implicit time and N75-P100 amplitude with any concentration of sevoflurane. At concentrations around 1.5 MAC, which are used routinely to immobilize dogs, sevoflurane showed no effect on P-VEP. PMID:25373729

  10. SVM-based visual-search model observers for PET tumor detection

    NASA Astrophysics Data System (ADS)

    Gifford, Howard C.; Sen, Anando; Azencott, Robert

    2015-03-01

    Many search-capable model observers follow task paradigms that specify clinically unrealistic prior knowledge about the anatomical backgrounds in study images. Visual-search (VS) observers, which implement distinct, feature-based candidate search and analysis stages, may provide a means of avoiding such paradigms. However, VS observers that conduct single-feature analysis have not been reliable in the absence of any background information. We investigated whether a VS observer based on multifeature analysis can overcome this background dependence. The testbed was a localization ROC (LROC) study with simulated whole-body PET images. Four target-dependent morphological features were defined in terms of 2D cross-correlations involving a known tumor profile and the test image. The feature values at the candidate locations in a set of training images were fed to a support-vector machine (SVM) to compute a linear discriminant that classified locations as tumor-present or tumor-absent. The LROC performance of this SVM-based VS observer was compared against the performances of human observers and a pair of existing model observers.

  11. Visualization of Patterns and Self-organization of Cellular Automata in Urban Traffic Situations

    NASA Astrophysics Data System (ADS)

    Zhou, Lei; Brian, Schwartz

    2001-06-01

    The use of cellular automaton (CA) techniques is very good at modeling complex or nonlinear systems. In dynamic system within the context of discrete mathematical steps for CA simulations, simple local rules produce complex global rules. The simplicity of CA rules enables us to model and investigate more realistic models for the behavior traffic in two-dimensional flow systems. Our numerical solution presents self-organization behavior, which is called grid-lock for urban city street traffic and a phase transitions in the fundamental flow rate vs. density diagrams. We present calculations, which demonstrate the effects of micro CA rules and traffic parameters on the macro properties of traffic flow and behavior. We modified the stochastic parameter p, which is constant in the original CA rules, to a variable depending on the state of the vehicles. This structure of path dependence on history for traffic properties is in many cases analogous to solutions obtained for interactive magnetic systems. Using 3D ray tracer software, we are able to render the visualization of patterns of grid-lock into a 3D virtual urban environment.

  12. Brain Activity Patterns Uniquely Supporting Visual Feature Integration after Traumatic Brain Injury

    PubMed Central

    Raja Beharelle, Anjali; Tisserand, Danielle; Stuss, Donald T.; McIntosh, Anthony R.; Levine, Brian

    2011-01-01

    Traumatic brain injury (TBI) patients typically respond more slowly and with more variability than controls during tasks of attention requiring speeded reaction time. These behavioral changes are attributable, at least in part, to diffuse axonal injury (DAI), which affects integrated processing in distributed systems. Here we use a multivariate method sensitive to distributed neural activity to compare brain activity patterns of patients with chronic phase moderate to-severe TBI to those of controls during performance on a visual feature integration task assessing complex attentional processes that has previously shown sensitivity to TBI. The TBI patients were carefully screened to be free of large focal lesions that can affect performance and brain activation independently of DAI. The task required subjects to hold either one or three features of a Target in mind while suppressing responses to distracting information. In controls, the multi-feature condition activated a distributed network including limbic, prefrontal, and medial temporal structures. TBI patients engaged this same network in the single-feature and baseline conditions. In multi-feature presentations, TBI patients alone activated additional frontal, parietal, and occipital regions. These results are consistent with neuroimaging studies using tasks assessing different cognitive domains, where increased spread of brain activity changes was associated with TBI. Our results also extend previous findings that brain activity for relatively moderate task demands in TBI patients is similar to that associated with of high task demands in controls. PMID:22180740

  13. Learning about Locomotion Patterns from Visualizations: Effects of Presentation Format and Realism

    ERIC Educational Resources Information Center

    Imhof, Birgit; Scheiter, Katharina; Gerjets, Peter

    2011-01-01

    The rapid development of computer graphics technology has made possible an easy integration of dynamic visualizations into computer-based learning environments. This study examines the relative effectiveness of dynamic visualizations, compared either to sequentially or simultaneously presented static visualizations. Moreover, the degree of realism…

  14. Exploring the interplay of visual and haptic modalities in a pattern-matching task

    Microsoft Academic Search

    Katie Seaborn; Bernhard E. Riecke; Alissa N. Antle

    2010-01-01

    It is not well understood how working memory deals with coupled haptic and visual presentation modes. Present theoretical understandings of human cognition indicate that these modes are processed by the visuospatial sketchpad. If this is accurate, then there may be no efficiency in distributing information between the haptic and visual modalities in situations of visual overload. However, this needs to

  15. Visual Inquiry Toolkit An Integrated Approach for Exploring and Interpreting Space-Time, Multivariate Patterns

    E-print Network

    Klippel, Alexander

    , computational, and cartographic methods to support the application of visual analytics to relatively large.e. potential interactions among space, time, and attributes) and scalability issues (i.e. both data volume visual, computational, and cartographic methods to support an overview+detail strategy for visual

  16. The effects of action video game experience on the time course of inhibition of return and the efficiency of visual search

    Microsoft Academic Search

    Alan D. Castel; Jay Pratt; Emily Drummond

    2005-01-01

    The ability to efficiently search the visual environment is a critical function of the visual system, and recent research has shown that experience playing action video games can influence visual selective attention. The present research examined the similarities and differences between video game players (VGPs) and non-video game players (NVGPs) in terms of the ability to inhibit attention from returning

  17. From Evolutionary Operation to Parallel Direct Search: Pattern Search Algorithms for Numerical Optimization

    E-print Network

    Torczon, Virginia

    that the Nelder-Mead algorithm may be unreliable even in fairly simple situations. In contrast, many that the Nelder-Mead simplex algorithm lacks. We will close with some practical sug- gestions for using pattern

  18. How Prior Knowledge and Colour Contrast Interfere Visual Search Processes in Novice Learners: An Eye Tracking Study

    ERIC Educational Resources Information Center

    Sonmez, Duygu; Altun, Arif; Mazman, Sacide Guzin

    2012-01-01

    This study investigates how prior content knowledge and prior exposure to microscope slides on the phases of mitosis effect students' visual search strategies and their ability to differentiate cells that are going through any phases of mitosis. Two different sets of microscope slide views were used for this purpose; with high and low colour…

  19. Tracking fear in snake and spider fearful participants during visual search: A multi-response domain study

    E-print Network

    Caldara, Roberto

    Tracking fear in snake and spider fearful participants during visual search: A multi snake or spider fearful participants showed shorter reaction times (RTs) to respond to their feared animal (e.g., snake) than to the nonfeared animal (i.e., spider) (O¨ hman, Flykt, & Esteves, 2001). Here

  20. Practice Makes Improvement: How Adults with Autism Out-Perform Others in a Naturalistic Visual Search Task

    ERIC Educational Resources Information Center

    Gonzalez, Cleotilde; Martin, Jolie M.; Minshew, Nancy J.; Behrmann, Marlene

    2013-01-01

    People with autism spectrum disorder (ASD) often exhibit superior performance in visual search compared to others. However, most studies demonstrating this advantage have employed simple, uncluttered images with fully visible targets. We compare the performance of high-functioning adults with ASD and matched controls on a naturalistic luggage…