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Journal of Vision Jun 2018Most research on texture density has utilized textures rendered as two-dimensional (2D) planar surfaces, consistent with the conventional definition of density as the...
Most research on texture density has utilized textures rendered as two-dimensional (2D) planar surfaces, consistent with the conventional definition of density as the number of texture elements per unit area. How the brain represents texture density information in the three-dimensional (3D) world is not yet clear. Here we tested whether binocular information affects density processing using simultaneous density contrast (SDC), in which the perceived density of a texture region is changed by a surround of different density. We considered the effect on SDC of two types of binocular information: the stereoscopic depth relationships and the interocular relationships between the center and surround textures. Observers compared the perceived density of two random dot patterns, one with a surround (test stimulus) and one without (match), using a 2AFC staircase procedure. In Experiment 1 we manipulated the stereo-depth of the surround plane systematically from near to far, relative to the center plane. SDC was reduced when the difference in stereo-depth between test center and surround increased. In Experiment 2 we spread the surround dots randomly across a stereo-depth volume from small to large volume sizes, and found that SDC was slightly reduced with volume size. The decrease of SDC in both experiments was observed with dense surrounds only, but not with sparse surrounds. In the last experiment we presented center and surround in the same depth plane but dichopticly, monopticly, and binocularly. A strong interocular transfer of SDC was found in the dichoptic condition. Together these results show that texture density processing is sensitive to binocularity.
Topics: Contrast Sensitivity; Densitometry; Depth Perception; Humans; Vision Disparity; Vision, Binocular
PubMed: 30029213
DOI: 10.1167/18.6.3 -
Journal of the History of the... 2016Visual representations of biological states have traditionally faced two problems: they lacked motion and depth. Attempts were made to supply these wants over many...
Visual representations of biological states have traditionally faced two problems: they lacked motion and depth. Attempts were made to supply these wants over many centuries, but the major advances were made in the early-nineteenth century. Motion was synthesized by sequences of slightly different images presented in rapid succession and depth was added by presenting slightly different images to each eye. Apparent motion and depth were combined some years later, but they tended to be applied separately. The major figures in this early period were Wheatstone, Plateau, Horner, Duboscq, Claudet, and Purkinje. Others later in the century, like Marey and Muybridge, were stimulated to extend the uses to which apparent motion and photography could be applied to examining body movements. These developments occurred before the birth of cinematography, and significant insights were derived from attempts to combine motion and depth.
Topics: Depth Perception; History, 19th Century; Humans; Medical Illustration; Motion; Optical Devices; Photography; United Kingdom
PubMed: 26684420
DOI: 10.1080/0964704X.2015.1070029 -
Journal of Biomedical Optics Jun 2015We proposed a glasses-free randot stereotest using a multiview display system. We designed a four-view parallax barrier system and proposed the use of a random-dot...
We proposed a glasses-free randot stereotest using a multiview display system. We designed a four-view parallax barrier system and proposed the use of a random-dot multigram as a set of view images for the glasses-free randot stereotest. The glasses-free randot stereotest can be used to verify the effect of glasses in a stereopsis experience. Furthermore, the proposed system is convertible between two-view and four-view structures so that the motion parallax effect could be verified within the system. We discussed the design principles and the method used to generate images in detail and implemented a glasses-free randot stereotest system with a liquid crystal display panel and a customized parallax barrier. We also developed graphical user interfaces and a method for their calibration for practical usage. We performed experiments with five adult subjects with normal vision. The experimental results show that the proposed system provides a stereopsis experience to the subjects and is consistent with the glasses-type randot stereotest and the Frisby–Davis test. The implemented system is free from monocular cues and provides binocular disparity only. The crosstalk of the system is about 6.42% for four-view and 4.17% for two-view, the time required for one measurement is less than 20 s, and the minimum angular disparity that the system can provide is about 23 arc sec.
Topics: Adult; Depth Perception; Equipment Design; Humans; User-Computer Interface; Vision Tests
PubMed: 26057031
DOI: 10.1117/1.JBO.20.6.065004 -
Cortex; a Journal Devoted To the Study... Sep 2016Brain areas critical for stereopsis have been investigated in non-human primates but are largely unknown in the human brain. Microelectrode recordings and functional MRI...
Brain areas critical for stereopsis have been investigated in non-human primates but are largely unknown in the human brain. Microelectrode recordings and functional MRI (fMRI) studies in monkeys have shown that in monkeys the inferior temporal cortex is critically involved in 3D shape categorization. Furthermore, some human fMRI studies similarly suggest an involvement of visual areas in the temporal lobe in depth perception. We aimed to investigate the role of the human anterior temporal neocortex in stereopsis by assessing stereoscopic depth perception before and after anterior temporal lobectomy. Eighteen epilepsy surgery patients were tested, pre- and postoperatively, in 3 different depth discrimination tasks. Sensitivity for local and global disparity was tested in a near-far discrimination task and sensitivity for 3D curvature was assessed in a convex-concave discrimination task, where 3D shapes were presented at different positions in depth. We found no evidence that temporal lobe epilepsy surgery has a significant effect on stereopsis. In contrast with earlier findings, we conclude that local as well as global stereopsis is maintained after unilateral resection of the temporal pole in epilepsy surgery patients. Our findings, together with previous studies, suggest that in humans more posterior visual regions underlie depth perception.
Topics: Adolescent; Adult; Anterior Temporal Lobectomy; Depth Perception; Epilepsy; Female; Humans; Male; Middle Aged; Perceptual Disorders; Photic Stimulation; Postoperative Complications; Psychophysics; Young Adult
PubMed: 27344239
DOI: 10.1016/j.cortex.2016.05.020 -
Cerebral Cortex (New York, N.Y. : 1991) May 2023An object's identity can influence depth-position judgments. The mechanistic underpinnings underlying this phenomenon are largely unknown. Here, we asked whether... (Randomized Controlled Trial)
Randomized Controlled Trial
An object's identity can influence depth-position judgments. The mechanistic underpinnings underlying this phenomenon are largely unknown. Here, we asked whether context-dependent modulations of stereoscopic depth perception are expertise dependent. In 2 experiments, we tested whether training that attaches meaning (i.e. classification labels) to otherwise novel, stereoscopically presented objects changes observers' sensitivity for judging their depth position. In Experiment 1, observers were randomly assigned to 3 groups: a Greeble-classification training group, an orientation-discrimination training group, or a no-training group, and were tested on their stereoscopic depth sensitivity before and after training. In Experiment 2, participants were tested before and after training while fMRI responses were concurrently imaged. Behaviorally, stereoscopic performance was significantly better following Greeble-classification (but not orientation-discrimination, or no-) training. Using the fMRI data, we trained support vector machines to predict whether the data were from the pre- or post-training sessions. Results indicated that classification accuracies in V4 were higher for the Greeble-classification group as compared with the orientation-discrimination group for which accuracies were at chance level. Furthermore, classification accuracies in V4 were negatively correlated with response times for Greeble identification. We speculate that V4 is implicated in an expertise-dependent, object-tuning manner that allows it to better guide stereoscopic depth retrieval.
Topics: Humans; Depth Perception; Reaction Time
PubMed: 36786066
DOI: 10.1093/cercor/bhad026 -
Journal of Cataract and Refractive... Feb 2020
Topics: Biometry; Clinical Competence; Depth Perception; Humans; Lens Implantation, Intraocular; Multifocal Intraocular Lenses; Optics and Photonics; Presbyopia; Prosthesis Design
PubMed: 32126026
DOI: 10.1097/j.jcrs.0000000000000128 -
Optics Express Mar 2020Foveation and (de)focus are two important visual factors in designing near eye displays. Foveation can reduce computational load by lowering display details towards the...
Foveation and (de)focus are two important visual factors in designing near eye displays. Foveation can reduce computational load by lowering display details towards the visual periphery, while focal cues can reduce vergence-accommodation conflict thereby lessening visual discomfort in using near eye displays. We performed two psychophysical experiments to investigate the relationship between foveation and focus cues. The first study measured blur discrimination sensitivity as a function of visual eccentricity, where we found discrimination thresholds significantly lower than previously reported. The second study measured depth discrimination threshold where we found a clear dependency on visual eccentricity. We discuss the study results and suggest further investigation.
Topics: Adult; Depth Perception; Humans; Middle Aged; Photic Stimulation; Sensory Thresholds; Visual Perception; Young Adult
PubMed: 32225914
DOI: 10.1364/OE.28.006734 -
Experimental Brain Research Apr 2020Size constancy is the ability to perceive objects as remaining constant in size regardless of their distance from the observer. Emmert's law demonstrates that viewing...
Size constancy is the ability to perceive objects as remaining constant in size regardless of their distance from the observer. Emmert's law demonstrates that viewing distance determines the perceived size of afterimages according to the amount of depth cues that are available. Using an afterimage paradigm, we examined to what extent removing stereopsis and other depth cues affects size-distance scaling. Thirty participants 'projected' afterimages onto a surface presented at different distances under binocular, monocular, and eyes-closed conditions. The perceived size of the afterimages closely followed the size-distance scaling predictions made by Emmert's law under binocular testing conditions, when all depth cues were available. In contrast, monocular testing decreased adherence to Emmert's law, while the eyes-closed condition resulted in a greater breakdown of size-distance scaling. Because we used an afterimage paradigm, this study provides the first demonstration of how perceived size is modulated by the availability of depth cues under conditions with a constant retinal image stimulus.
Topics: Adult; Afterimage; Depth Perception; Distance Perception; Female; Humans; Male; Psychological Theory; Size Perception; Vision, Binocular; Vision, Monocular; Young Adult
PubMed: 32215670
DOI: 10.1007/s00221-020-05747-5 -
Annual Review of Vision Science Sep 2020Scene processing is fundamentally influenced and constrained by spatial layout and spatial associations with objects. However, semantic information has played a vital... (Review)
Review
Scene processing is fundamentally influenced and constrained by spatial layout and spatial associations with objects. However, semantic information has played a vital role in propelling our understanding of real-world scene perception forward. In this article, we review recent advances in assessing how spatial layout and spatial relations influence scene processing. We examine the organization of the larger environment and how we take full advantage of spatial configurations independently of semantic information. We demonstrate that a clear differentiation of spatial from semantic information is necessary to advance research in the field of scene processing.
Topics: Attention; Depth Perception; Humans; Memory; Pattern Recognition, Visual; Spatial Processing
PubMed: 32491961
DOI: 10.1146/annurev-vision-121219-081745 -
Journal of Vision Jun 2016The visual system can process three-dimensional depth cues defining surfaces of objects, but it is unclear whether such information contributes to complex object...
The visual system can process three-dimensional depth cues defining surfaces of objects, but it is unclear whether such information contributes to complex object recognition, including face recognition. The processing of different depth cues involves both dorsal and ventral visual pathways. We investigated whether facial surfaces defined by individual depth cues resulted in meaningful face representations-representations that maintain the relationship between the population of faces as defined in a multidimensional face space. We measured face identity aftereffects for facial surfaces defined by individual depth cues (Experiments 1 and 2) and tested whether the aftereffect transfers across depth cues (Experiments 3 and 4). Facial surfaces and their morphs to the average face were defined purely by one of shading, texture, motion, or binocular disparity. We obtained identification thresholds for matched (matched identity between adapting and test stimuli), non-matched (non-matched identity between adapting and test stimuli), and no-adaptation (showing only the test stimuli) conditions for each cue and across different depth cues. We found robust face identity aftereffect in both experiments. Our results suggest that depth cues do contribute to forming meaningful face representations that are depth cue invariant. Depth cue invariance would require integration of information across different areas and different pathways for object recognition, and this in turn has important implications for cortical models of visual object recognition.
Topics: Adaptation, Physiological; Adult; Cues; Depth Perception; Emotions; Face; Female; Humans; Male; Neuropsychological Tests; Pattern Recognition, Visual; Reaction Time; Vision Disparity; Visual Pathways; Young Adult
PubMed: 27271993
DOI: 10.1167/16.8.6