Document Detail


What spatial frequency do we use to detect the orientation of a Landolt C?
MedLine Citation:
PMID:  9327062     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We calculated the two-dimensional Fourier spectrum of a Landolt C. For Landolt Cs of orthogonal orientation, the main differences in the amplitude spectrum were found at a low frequency such that 1.3 periods were equal to the size fo the Landolt C, rather than at the high frequency corresponding to the size of the gap, i.e., such that 2.5 periods were equal to the size of the Landolt C. We compared visual acuity assessments obtained with Landolt C optotypes and the cut-off of the contrast sensitivity function measured with sinusoidal gratings. We found that the frequency corresponding to the size of the gap is twice the latter frequency. We suggest that, in fact, this lower frequency can be used to determine the position of the gap.
Authors:
V M Bondarko; M V Danilova
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 Aug 
Date Detail:
Created Date:  1997-10-27     Completed Date:  1997-10-27     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0417402     Medline TA:  Vision Res     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  2153-6     Citation Subset:  IM    
Affiliation:
Laboratory for Vision Physiology, I. P. Pavlov Institute of Physiology, St. Petersburg, Russia. lera@vbond.usr.pu.ru
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MeSH Terms
Descriptor/Qualifier:
Fourier Analysis
Humans
Pattern Recognition, Visual / physiology
Rotation*
Space Perception / physiology*
Vision Tests*
Visual Acuity*

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


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