Document Detail

Scale selection for second-order (non-linear) stereopsis.
MedLine Citation:
PMID:  9425514     Owner:  NLM     Status:  MEDLINE    
In addition to the conventional luminance spatial frequency-dependent, disparity processing mode, there is a second-order luminance spatial frequency-independent type of processing available to the stereoscopic system. Here we use gaussian-enveloped, amplitude-modulated grating patches to determine how the stereoscopic system responds to the presence of two sources of second-order disparity information at different scales when there is no disparity information available via the conventional luminance-based system. In the first experiment we show that the stereoscopic system uses the disparity signal provided by the stimulus envelope, even though it is at a coarser scale than that provided by the amplitude modulation (AM). We then demonstrate that if the stimulus envelope is degraded via blurring, or if it is fixed at zero disparity, then performance depends on the finer-scale AM disparity signal. To show that the stereoscopic system uses the disparity signal provided by the AM we extend the carrier grating outside the borders of the AM stimulus, thereby making the boundary of the patch less discernible. Results obtained using this stimulus suggest that when two sources of second-order disparity information are present within the same stimulus (i.e., with no reliable luminance-based disparity signal available), the disparity signal provided by the coarser-scale contrast envelope vetos the finer-scale disparity signal. The coarse-scale disparity information dominates as long at it provides an adequate disparity signal. When it is degraded, however, the finer-scale signal takes precedence.
L M Wilcox; R F Hess
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Vision research     Volume:  37     ISSN:  0042-6989     ISO Abbreviation:  Vision Res.     Publication Date:  1997 Nov 
Date Detail:
Created Date:  1998-02-02     Completed Date:  1998-02-02     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0417402     Medline TA:  Vision Res     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  2981-92     Citation Subset:  IM; S    
Department of Psychology, York University, Ontario, Canada.
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MeSH Terms
Depth Perception / physiology*
Photic Stimulation / methods
Vision Disparity / physiology*
Visual Acuity

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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