Document Detail

Critical band masking in optic flow.
MedLine Citation:
PMID:  16411499     Owner:  NLM     Status:  MEDLINE    
Visual processing has been widely investigated with narrow band stimuli at low contrasts. We used a masking paradigm to examine how visual sensitivity under these conditions compares with the perception of the direction of heading in real scenes (i.e., with dynamic natural images at high contrasts). We first confirmed and extended previous studies showing biases in the amplitude distribution for spatial frequency, temporal frequency, speed and direction in dynamic natural movies. We then measured contrast thresholds for identification of the direction of motion for an observer traveling at various speeds. In spite of differences in contrast sensitivity and large non-uniformities in the amplitude content of the stimuli, contrast thresholds were relatively invariant of spatial frequency and completely invariant of temporal frequency, speed and direction. Our results suggest that visual processing normalises responses to supra-threshold structure at different spatial and temporal frequencies within natural stimuli and so equates their effective visibility.
Peter J Bex; Steven C Dakin; Isabelle Mareschal
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Publication Detail:
Type:  Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Network (Bristol, England)     Volume:  16     ISSN:  0954-898X     ISO Abbreviation:  Network     Publication Date:    2005 Jun-Sep
Date Detail:
Created Date:  2006-01-16     Completed Date:  2006-02-09     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9431867     Medline TA:  Network     Country:  England    
Other Details:
Languages:  eng     Pagination:  261-84     Citation Subset:  IM    
Division of Visual Rehabilitation Research, The Institute of Ophthalmology, London, UK.
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MeSH Terms
Contrast Sensitivity / physiology*
Discrimination Learning / physiology*
Models, Neurological*
Motion Perception / physiology*
Pattern Recognition, Visual / physiology*
Perceptual Masking / physiology*
Photic Stimulation / methods
Sensory Thresholds / physiology

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

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