Document Detail


On the half-cycle displacement limit of sampled directional motion.
MedLine Citation:
PMID:  1843767     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We employed filtered random-dot kinematograms to determine the maximum displacement (dmax) at which sampled directional motion was reliably detected. The images were produced using ideal band-pass filters that varied in lower cut-off frequency (f1), in bandwidth, and in range (alpha) of component orientations that were passed. Results showed that dmax, expressed in cycles of f1, increased with f1 and alpha, and decreased with bandwidth. In many conditions, dmax exceeded half a cycle of f1, a result that appears to contradict predictions from quadrature models of motion detection. However, an account that does not violate the half-cycle limit can be given on two assumptions. First, motion perception is mediated by a population of orientation and frequency-selective sensors that respond correctly to displacements up to half a cycle in the preferred direction. Second, the outputs from all sensors (notably including off-axis sensors) are linearly summated to yield perception of motion. A computer simulation based on these assumptions provided a remarkably close fit to the psychophysical data.
Authors:
W F Bischof; V Di Lollo
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Vision research     Volume:  31     ISSN:  0042-6989     ISO Abbreviation:  Vision Res.     Publication Date:  1991  
Date Detail:
Created Date:  1993-03-12     Completed Date:  1993-03-12     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0417402     Medline TA:  Vision Res     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  649-60     Citation Subset:  IM; S    
Affiliation:
Department of Psychology, University of Alberta, Edmonton, Canada.
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MeSH Terms
Descriptor/Qualifier:
Computer Simulation
Humans
Mathematics
Motion Perception / physiology*
Psychophysics

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


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