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Vision Research Mar 2005Dichoptic stimuli containing unmatched features can produce depth perception despite the absence of binocular disparity, a phenomenon known as da Vinci stereopsis....
Dichoptic stimuli containing unmatched features can produce depth perception despite the absence of binocular disparity, a phenomenon known as da Vinci stereopsis. Unmatched points can arise from depth discontinuities and partial occlusion in the real world. It has been hypothesized that spatial organization of unmatched image features as dictated by the ecological optics of occlusion might determine perceived depth in da Vinci stereopsis. We tested this hypothesis by creating dichoptic stimuli containing unmatched points in which local cues and overall organization could be dissociated. For these stimuli, observers' perception of depth did not depend on the organization of the scene, but only on the local cues. This finding shows the perceived depth of unpaired points need not depend on reconstructing the spatial organization of depth discontinuities in real-world scenes.
Topics: Depth Perception; Form Perception; Humans; Pattern Recognition, Visual; Vision Disparity; Vision, Binocular
PubMed: 15621172
DOI: 10.1016/j.visres.2004.09.015 -
Vision Research Mar 2005Our visual system matches images from both eyes to establish a single view and stereo depth even when they contain a certain amount of vertical disparity. This paper...
Our visual system matches images from both eyes to establish a single view and stereo depth even when they contain a certain amount of vertical disparity. This paper demonstrates a new stereo effect showing an aspect of vertical disparity processing. When oblique lines without disparity are overlaid with sparse random dots with vertical disparity, the lines look closer or farther in depth. The characteristics of this stereo illusion were experimentally investigated. The results showed that the sign of the perceived depth of the oblique lines depended on the combination of the line orientation and the vertical disparity sign, and that the amount of perceived depth became larger as the line orientation became more horizontal. The depth illusion robustly existed even under conditions that ruled out eye movements (i.e., vertical vergence and cyclovergence) by local-parallel or brief presentations of the stereo figures. This phenomenon suggests that the visual system locally measures vertical disparity and is not simply tolerating a small amount of vertical disparity. Stereo capture of vertical disparity and horizontal matching after vertical image shifts were proposed as possible explanations for the depth illusion.
Topics: Depth Perception; Humans; Male; Optical Illusions; Orientation; Photic Stimulation; Psychophysics; Vision Disparity; Vision, Binocular
PubMed: 15644231
DOI: 10.1016/j.visres.2004.10.008 -
Journal of Vision Nov 2018Binocular disparity signals can provide high acuity information about the positions of points, surfaces, and objects in three-dimensional space. For some stimulus...
Binocular disparity signals can provide high acuity information about the positions of points, surfaces, and objects in three-dimensional space. For some stimulus configurations, however, perceived depth is known to be affected by surface organization. Here we examine the effects of surface continuity and discontinuity on such surface organization biases. Participants were presented with a series of random dot surfaces, each with a cumulative Gaussian form in depth. Surfaces varied in the steepness of disparity gradients, via manipulation of the standard deviation of the Gaussian, and/or the presence of differing forms of surface discontinuity. By varying the relative disparity between surface edges, we measured the points of subjective equality, where surfaces of differing steepness and/or discontinuity were perceptually indistinguishable. We compare our results to a model that considers sensitivity to different frequencies of disparity modulation. Across a series of experiments, the observed patterns of change in points of subjective equality suggest that perceived depth is determined by the integration of measures of relative disparity, with a bias toward sharp changes in disparity. Such disparities increase perceived depth when they are in the same direction as the overall disparity. Conversely, perceived depth is reduced by the presence of sharp disparity changes that oppose the sign of the overall depth change.
Topics: Adult; Bias; Depth Perception; Female; Humans; Male; Normal Distribution; Vision Disparity; Vision, Binocular
PubMed: 30458518
DOI: 10.1167/18.12.13 -
Psychonomic Bulletin & Review Aug 2020Although spatial attention has been found to alter the subjective appearance of visual stimuli in several perceptual dimensions, no research has explored whether...
Although spatial attention has been found to alter the subjective appearance of visual stimuli in several perceptual dimensions, no research has explored whether exogenous spatial attention can affect depth perception, which is a fundamental dimension in perception that allows us to effectively interact with the environment. Here, we used an experimental paradigm adapted from Gobell and Carrasco (Psychological Science, 16[8], 644-651, 2005) to investigate this question. A peripheral cue preceding two line stimuli was used to direct exogenous attention to either location of the two lines. The two lines were separated by a certain relative disparity, and participants were asked to judge the perceived depth of two lines while attention was manipulated. We found that a farther stereoscopic depth at the attended location was perceived to be equally distant as a nearer depth at the unattended location. No such effect was found in a control experiment that employed a postcue paradigm, suggesting that our findings could not be attributed to response bias. Therefore, our study shows that exogenous spatial attention shortens perceived depth. The apparent change in stereoscopic depth may be regulated by a mechanism involving direct neural enhancement on those tuned to disparity, or be modulated by an attentional effect on apparent contrast. This finding shows that attention can change not only visual appearance but also the perceived spatial relation between an object and an observer.
Topics: Adolescent; Adult; Attention; Cues; Depth Perception; Female; Humans; Male; Vision Disparity; Young Adult
PubMed: 32319001
DOI: 10.3758/s13423-020-01724-9 -
Journal of Vision Jun 2018Local depth variation is a distinctive property of natural scenes, but its effects on perception have only recently begun to be investigated. Depth variation in natural...
Local depth variation is a distinctive property of natural scenes, but its effects on perception have only recently begun to be investigated. Depth variation in natural scenes is due to depth edges between objects and surface nonuniformities within objects. Here, we demonstrate how natural depth variation impacts performance in two fundamental tasks related to stereopsis: half-occlusion detection and disparity detection. We report the results of a computational study that uses a large database of natural stereo-images and coregistered laser-based distance measurements. First, we develop a procedure for precisely sampling stereo-image patches from the stereo-images and then quantify the local depth variation in each patch by its disparity contrast. Next, we show that increased disparity contrast degrades half-occlusion detection and disparity detection performance and changes the size and shape of the spatial integration areas ("receptive fields") that optimize performance. Then, we show that a simple image-computable binocular statistic predicts disparity contrast in natural scenes. Finally, we report the most likely spatial patterns of disparity variation and disparity discontinuities (half-occlusions) in natural scenes. Our findings motivate computational and psychophysical investigations of the mechanisms that underlie stereo processing tasks in local regions of natural scenes.
Topics: Depth Perception; Humans; Psychophysics; Vision Disparity; Vision, Binocular; Visual Perception
PubMed: 30029214
DOI: 10.1167/18.6.4 -
Brain and Nerve = Shinkei Kenkyu No... Nov 2021This paper explains the basics of depth perception and explores why both eyes are aligned. We concluded that the brain may analyze image features for binocular fusion...
This paper explains the basics of depth perception and explores why both eyes are aligned. We concluded that the brain may analyze image features for binocular fusion while calculating the horizontal disparity for depth perception.
Topics: Depth Perception; Humans; Vision Disparity
PubMed: 34759059
DOI: 10.11477/mf.1416201921 -
Vision Research May 2019Stereoscopic depth is most useful when it comes from relative rather than absolute disparities. However, the depth perceived from relative disparities can vary with...
Stereoscopic depth is most useful when it comes from relative rather than absolute disparities. However, the depth perceived from relative disparities can vary with stimulus parameters that have no connection with depth or are irrelevant to the task. We investigated observers' ability to judge the stereo depth of task-relevant stimuli while ignoring irrelevant stimuli. The calculation of depth from disparity differs for 1-D and 2-D stimuli and we investigated the role this difference plays in observers' ability to selectively process relevant information. We show that the presence of irrelevant disparities affects perceived depth differently depending on stimulus dimensionality. Observers could not ignore disparities of irrelevant stimuli when they judged the relative depth between a 1-D stimulus (a grating) and a 2-D stimulus (a plaid). Yet these irrelevant disparities did not affect judgments of the relative depth between 2-D stimuli. Two processes contributing to stereo depth were identified, only one of which computes depth from a horizontal disparity metric and permits attentional selection. The other uses all stimuli, relevant and irrelevant, to calculate an effective disparity direction for comparing disparity magnitudes. These processes produce inseparable effects in most data sets. Using multiple disparity directions and comparing 1-D and 2-D stimuli can distinguish them.
Topics: Attention; Depth Perception; Humans; Judgment; Lighting; Photic Stimulation; Vision Disparity; Vision, Binocular
PubMed: 30771360
DOI: 10.1016/j.visres.2018.08.007 -
Scientific Reports May 2022Motion-in-depth perception is critical in enabling animals to avoid hazards and respond to potential threats. For humans, important visual cues for motion-in-depth...
Motion-in-depth perception is critical in enabling animals to avoid hazards and respond to potential threats. For humans, important visual cues for motion-in-depth include changing disparity (CD) and changing image size (CS). The interpretation and integration of these cues depends upon multiple scene parameters, such as distance moved, object size and viewing distance, posing a significant computational challenge. We show that motion-in-depth cue integration depends upon sensitivity to the joint probabilities of the scene parameters determining these signals, and on the probability of CD and CS signals co-occurring. Models that took these factors into account predicted human performance in speed-in-depth and cue conflict discrimination tasks, where standard linear integration models could not. These results suggest that cue integration is affected by both the uncertainty of sensory signals and the mapping of those signals to real-world properties. Evidence of a role for such mappings demonstrates the importance of scene and image statistics to the processes underpinning cue integration and the perception of motion-in-depth.
Topics: Cues; Depth Perception; Motion; Motion Perception; Vision Disparity
PubMed: 35562584
DOI: 10.1038/s41598-022-12051-5 -
Journal of Vision Jan 2013Temporal characteristics of depth perception from motion parallax were examined by modulating parallax intermittently while observers moved their head side to side. In... (Comparative Study)
Comparative Study
Temporal characteristics of depth perception from motion parallax were examined by modulating parallax intermittently while observers moved their head side to side. In Experiment 1, parallax of a fixed value was introduced only for the central 1/6 to 5/6 portion of each component head movement. It was found that the perceived depth was proportional to the temporal average of parallax-specified depth. In addition, observers did not notice any abrupt temporal change of depth. In Experiment 2, parallax was increased or decreased once per trial either at the center or the end of one of the component head movements, and observers judged the direction of depth change. Again, observers did not notice any abrupt change of depth. The percentage of correct responses was almost constant for large change amplitudes. Reaction times to the change were over 1 s even for the largest changes, and it increased for smaller change amplitudes. These results indicate that the mechanism for depth from parallax has a configuration similar to that proposed for structure from motion, and that it involves a temporal integration process with a relatively long time-constant.
Topics: Depth Perception; Head Movements; Humans; Motion; Motion Perception; Photic Stimulation
PubMed: 23308024
DOI: 10.1167/13.1.16 -
Topics in Cognitive Science Oct 2011Two experiments were performed to explore the mechanisms of human 3D shape perception. In Experiment 1, the subjects' performance in a shape constancy task in the...
Two experiments were performed to explore the mechanisms of human 3D shape perception. In Experiment 1, the subjects' performance in a shape constancy task in the presence of several cues (edges, binocular disparity, shading and texture) was tested. The results show that edges and binocular disparity, but not shading or texture, are important in 3D shape perception. Experiment 2 tested the effect of several simplicity constraints, such as symmetry and planarity on subjects' performance in a shape constancy task. The 3D shapes were represented by edges or vertices only. The results show that performance with or without binocular disparity is at chance level, unless the 3D shape is symmetric and/or its faces are planar. In both experiments, there was a correlation between the subjects' performance with and without binocular disparity. Our study suggests that simplicity constraints, not depth cues, play the primary role in both monocular and binocular 3D shape perception. These results are consistent with our computational model of 3D shape recovery.
Topics: Adult; Cues; Depth Perception; Form Perception; Humans; Models, Psychological; Vision Disparity
PubMed: 25164504
DOI: 10.1111/j.1756-8765.2011.01155.x