The accuracy of depth judgments that are based on binocular disparity or structure from motion (motion parallax and object rotation) was studied in 3 experiments. In Experiment 1, depth judgments were recorded for computer simulations of cones specified by binocular disparity, motion parallax, or stereokinesis. In Experiment 2, judgments were recorded for real cones in a structured environment, with depth information from binocular disparity, motion parallax, or object rotation about the y-axis. In both of these experiments, judgments from binocular disparity information were quite accurate, but judgments on the basis of geometrically equivalent or more robust motion information reflected poor recovery of quantitative depth information. A 3rd experiment demonstrated stereoscopic depth constancy for distances of 1 to 3 m using real objects in a well-illuminated, structured viewing environment in which monocular depth cues (e.g., shading) were minimized. It has been pointed out that the geometric information supporting the perception of depth from binocular disparity is actually less determinate than that supporting the recovery of structure from object rotation or motion parallax

In two experiments, we examine how observers ierversMEzE themiMCVj parts of sampled, planar contoursi 3-D space. We variz (1) contour type(liMkC orparabolizk (2)oriEj#fiMxz of the planecontaiVzz the contour and (3) the number ofpoiqfi on a sampled contour. InterpolatiE performance was very accurate, comparable to results fromVerniC tasks. SettiM variMCfifiFfi washiMz#j along the lie ofsijj and for theparaboli contour.Settir varir.MEV# decreasewir ireaseMCz number ofpoizj oneizfiF contour, suggestiF that observers do not use all avaiFqFMx relevantievantMEjq in this task.

Recently, there has been a great increase in interest in using three dimensional stereoscopic displays to provide viewers with realistic 3D views of objects of interest. Some applications where stereoscopic displays are becoming popular include medical visualization, visualization of meteorological data, and various virtual reality applications. To quantify the effectiveness of stereoscopic systems over conventional monoscopic systems, well-designed experiments and data analysis methods are necessary. This task requires the combined effort of application scientists and experts in experimental design. Lack of interdisciplinary collaboration is a primary weakness of many stereoscopic display studies, resulting in the neglect of many important but subtle experimental issues. In this paper, we discuss specific issues that arise in the design of studies to determine the effectiveness of digital stereo imagery. Issues concerning statistical analysis of the experimental data are also discusse...

A fundamental problem in the study of spatial perception concerns whether and how vision might acquire information about the metric structure of surfaces inthree-dimensionaLspacefrom motion and from stereopsis. Theoretical analyses have indicated that stereoscopic perceptions of metric relations in depth require additional information about egocentric viewing distance; and recent experiments by James Todd and his colleagues have indicated that vision acquires only afline but notmetric structure from motion—that is, spatial relations ambiguouswith regard to scale in depth. The purpose of the present study was to determine whether the metric shape ofplanar stereoscopic forms might be perceived from congruence underplanar rotation. In Experiment 1, observers discriminated between similar planar shapes (ellipses) rotating in a plane with varying slant from the frontal-parallel plane. Experimental conditions varied the presence versus absence of binocular disparities, magnification of the disparity scale, and moving versus stationary patterns. Shape discriminations were accurate in all conditions withmovingpatterns and were near chance in conditions with stationary patterns; neither-the- presence nor the magnification of binocular disparities had any reliable effect. In Experiment 2, accuracy decreased as the range of rotation decreased from 800 to 100. In Experiment 3, small deviations from planarity of the motion

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The visual system continuously integrates multiple sensory cues to help plan and control everyday motor tasks. We quantified how subjects integrated monocular cues (contour and texture) and binocular cues (disparityand vergence) about 3D surface orientation throughout an object placement task and found that binocular cues contributed more to online control than planning. A temporal analysis of corrective responses to stimulus perturbations revealed that the visuomotor system processes binocular cues faster than monocular cues. This suggests that binocular cues dominated online control because theywere available sooner, thus affecting a larger proportion of the movement. This was consistent with our finding that the relative influence of binocular information was higher for short-duration movements than long-duration movements. A motor control model that optimallyintegrates cues with different delays accounts for our findings and shows that cue integration for motor control depends in part on the time course

With normal binocular vision, maximal stereoacuity requires an extended viewing duration, but the relationship between the critical viewing duration for stereopsis and other variables affecting stereoacuity is unknown. The purposes of the study were to investigate the properties of normal temporal integration for stereoscopic vision with respect to the effects of contrast and spatial frequency of the stimuli and to determine whether the temporal summation of disparity is affected in deficient stereopsis caused by abnormal binocular vision during infancy. Psychophysical methods were used to measure stereothresholds in human and monkey subjects with either normal binocular vision or abnormal binocular vision. The results showed that the critical viewing duration for stereoscopic depth discrimination was independent of variations in basic stimulus parameters and/or the subjectÕs stereoacuity. A critical duration of approximately 100 ms was found for both local (narrowband Gabor and broadband line targets) and global (dynamic random dots) stimuli. Although stereothresholds increased with decreasing stimulus contrast, the properties of temporal integration did not. Stereothresholds were substantially elevated for monkeys and humans with abnormal binocular vision, but the critical durations for these subjects were not significantly different from those of subjects with normal binocular vision. Overall, the results demonstrate that the general properties of temporal integration for stereopsis are similar to other detection and discrimination tasks that do not require binocular processing. In addition, increased integration time does not account for the elevated stereothresholds of subjects with abnormal binocular vision.

Previous models of stereopsis have concentrated on the task of binocularly matching left and right eye primith'es uniquely. A disparity smoothness constraint is often invoked to limit the number of possible matches. These approaches neglect the fact that surface discontinuities are both abundant in natural eve!)'day scenes, and provide a useful cue for scene segmentation. da Vinci stereopsis refers to the more general problern of dealing Ivith surface discontinuities and their associated unmatched monocular regions}vithin binocular scenes. This study develops a mathematical realization of a neural netlvork theory of biological vision, called FACADE theo!)', that sholvs holY early cortical stereopsis processes are related to later cortical processes of three-dimensional surface representation. The mathematical model demonstrates through computer simulation holY the visual cortex Inay generate threedilnensional boundary segmentations and use them to control filling-in of three-dimensional surface properties in response to visual scenes. Model mechanisms correctly match disparate binocular regions while filling-in monocular regions Ivith the correct depth within a binocularly viewed scene. This achievelnent required the introduction of a new multiscale binocular filter for;\'tereo matching}vhich clarifies holv cortical complex cells match image contours of like contrast polarity, while pooling signals from opposite contrast polarities. The filter also suggests how false binocular matches and unmatched monocular cues are automatically handled across multiple spatial scales. Pooling of signals froln even- and odd-S)'lnmetric simple cells at complex cells helps to eliminate spurious activity peaks in matchable