scholarly journals Processing of first and second order binocular disparity by the human visual system

2012 ◽  
Vol 12 (9) ◽  
pp. 39-39
Author(s):  
C. Quaia ◽  
B. Sheliga ◽  
L. Optican ◽  
B. Cumming
Keyword(s):  
Visual System ◽  
Human Visual System ◽  
Binocular Disparity ◽  
Second Order

Interaction between Transparency and Structure from Motion

1992 ◽  
Vol 4 (4) ◽  
pp. 573-589 ◽  
Author(s):  
Daniel Kersten ◽  
Heinrich H. Bülthoff ◽  
Bennett L. Schwartz ◽  
Kenneth J. Kurtz
Keyword(s):  
Visual System ◽  
Structure From Motion ◽  
Human Visual System ◽  
Binocular Disparity ◽  
Rigid Motion ◽  
Motion Information ◽  
Low Level ◽  
Visual Process ◽  
Pictorial Cues

It is well known that the human visual system can reconstruct depth from simple random-dot displays given binocular disparity or motion information. This fact has lent support to the notion that stereo and structure from motion systems rely on low-level primitives derived from image intensities. In contrast, the judgment of surface transparency is often considered to be a higher-level visual process that, in addition to pictorial cues, utilizes stereo and motion information to separate the transparent from the opaque parts. We describe a new illusion and present psychophysical results that question this sequential view by showing that depth from transparency and opacity can override the bias to see rigid motion. The brain's computation of transparency may involve a two-way interaction with the computation of structure from motion.

The Discriminability of Local Surface Structure

Perception ◽  
1996 ◽  
Vol 25 (4) ◽  
pp. 381-398 ◽  
Author(s):  
J Farley Norman ◽  
James T Todd
Keyword(s):  
Visual System ◽  
Surface Structure ◽  
Human Visual System ◽  
Binocular Disparity ◽  
Qualitative Difference ◽  
Surface Orientation ◽  
Sources Of Information ◽  
Local Surface ◽  
Projected Image ◽  
Image Separation

The ability of observers to discriminate depth and orientation differences between separated local regions on object surfaces was examined. The objects were defined by many optical sources of information simultaneously, including shading, texture, motion, and binocular disparity. Despite the full-cue nature of the displays, the observers' performance was relatively poor, with Weber fractions ranging from 10% to 40%. The Weber fractions were considerably lower for discriminations of surface-orientation differences than for similar discriminations of depth differences. The ability of observers to discriminate surface-orientation differences was approximately invariant over the separation of the regions in the projected image. In contrast, the ability to discriminate depth differences was highly influenced by the amount of image separation. This qualitative difference between the perception of depth intervals and surface-orientation differences suggests that knowledge of depths and orientations may be represented separately within the human visual system.

Disparity-tuned channels of the human visual system

1993 ◽  
Vol 10 (4) ◽  
pp. 585-596 ◽  
Author(s):  
Lawrence K. Cormack ◽  
Scott B. Stevenson ◽  
Clifton M. Schor
Keyword(s):  
Visual System ◽  
Human Visual System ◽  
Single Unit ◽  
Binocular Disparity ◽  
Random Element ◽  
Stereoscopic Depth ◽  
Detection Thresholds ◽  
Strict Adherence ◽  
Low Level ◽  
Single Unit Recordings

AbstractTraditionally, it has been thought that the processing of binocular disparity for the perception of stereoscopic depth is accomplished via three types of disparity-selective channels – “near,” “far,” and “tuned.” More recent evidence challenges this notion. We have derived disparity-tuning functions psychophysically using a subthreshold summation (i.e. low-level masking) technique. We measured correlation-detection thresholds for dynamic random-element stereograms containing either one or two surfaces in depth. The resulting disparity-tuning functions show an opponent-type profile, indicating the presence of inhibition between disparity-tuned units in the visual system. Moreover, there is clear inhibition between disparities of the same sign, obviating a strict adherence to near-far opponency. These results compare favorably with tuning functions derived psychophysically using an adaptation technique, and with the tuning profiles from published single-unit recordings. Our results suggests a continuum of overlapping disparity-tuned channels, which is consistent with recent physiological evidence as well as models based on other psychophysical data.

Nonlinear Analysis of Visual Evoked Potentials Elicited by Color Stimulation

1997 ◽  
Vol 36 (04/05) ◽  
pp. 315-318 ◽  
Author(s):  
K. Momose ◽  
K. Komiya ◽  
A. Uchiyama
Keyword(s):  
Visual System ◽  
Evoked Potentials ◽  
Visual Evoked Potentials ◽  
Normal Subjects ◽  
Second Order ◽  
First Order ◽  
The Relationship ◽  
Perceived Color ◽  
Second Order Nonlinearity ◽  
Visual Evoked

Abstract:The relationship between chromatically modulated stimuli and visual evoked potentials (VEPs) was considered. VEPs of normal subjects elicited by chromatically modulated stimuli were measured under several color adaptations, and their binary kernels were estimated. Up to the second-order, binary kernels obtained from VEPs were so characteristic that the VEP-chromatic modulation system showed second-order nonlinearity. First-order binary kernels depended on the color of the stimulus and adaptation, whereas second-order kernels showed almost no difference. This result indicates that the waveforms of first-order binary kernels reflect perceived color (hue). This supports the suggestion that kernels of VEPs include color responses, and could be used as a probe with which to examine the color visual system.

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