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Random dot techniques were used to investigate the human visual system's sensitivity to sinusoidal depth modulations specified by motion parallax information. Thresholds for perceiving depth were found to be smallest when the spatial frequency of the depth corrugations was between 0.2 and 0.5 c/deg visual angle. These data were compared with the equivalent(More)
The perspective transformations of the retinal image, produced by either the movement of an observer or the movement of objects in the visual world, were found to produce a reliable, consistent, and unambiguous impression of relative depth in the absence of all other cues to depth and distance. The stimulus displays consisted of computer-generated(More)
Binocular disparity can be defined in a variety of ways and its measurement depends upon the particular coordinate framework chosen. As a result of the inverse square law, binocular disparities need to be scaled by some estimate of absolute distance if they are to be interpreted correctly. The experiments described in this paper investigated the extent to(More)
To calculate the depth difference between a pair of points on a three-dimensional surface from binocular disparities, it is necessary to know the absolute distance to the surface. Traditionally, it has been assumed that this information is derived from non-visual sources such as the vergence angle of the eyes. It has been shown that the horizontal gradient(More)
Under identical viewing conditions, observers made two types of judgement about the shape of stereoscopically defined surfaces: one required an estimate of viewing distance for correct performance (e.g. setting the depth of a hemi-cylinder to equal its half-height or a dihedral angle to 90 deg), the other did not (matching the depth of, for example,(More)
The present study compared the relative effectiveness of differential perspective and vergence angle manipulations in scaling depth from horizontal disparities. When differential perspective and vergence angle were manipulated together (to simulate a range of different viewing distances from 28 cm to infinity), approximately 35% of the scaling required for(More)
Sensitivity to corrugations defined by binocular disparity differs as a function of the modulation frequency. Such functions have proved to be useful descriptive and analytical tools in the study of the mechanisms involved in disparity processing. Indeed, given certain assumptions, these sensitivity functions can be used to predict certain perceptual(More)
Depth from binocular disparity and motion parallax has traditionally been assumed to be the product of separate and independent processes. We report two experiments which used classical psychophysical paradigms to test this assumption. The first tested whether there was an elevation in the thresholds for detecting the 3D structure of corrugated surfaces(More)
Ahstract-The visual system usualiy sees phi apparent movement when two similar pictures are exposed successively, and stereoscopic depth when the pictures are exposed one to each eye. But when a picture was followed via a dissolve by its own photographic negative, overlapping but displaced. strong apparent movement was seen in the opposite direction to the(More)
Two-frame random-element kinematograms were used to study the matching algorithm employed by the visual system to keep track of moving elements. Previous data have shown that the maximum spatial displacement detectable (dmax) for random-dot kinematogram stimuli increases both with increasing dot size and with decreasing centre frequency for spatially(More)