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Detection in fixed and random noise in foveal and parafoveal vision explained by template learningFoveal and parafoveal contrast detection thresholds for Gabor and checkerboard targets were measured in white noise by means of a two-interval forced-choice paradigm. Two white-noise conditions were used: fixed and twin. In the fixed noise condition a single noise sample was presented in both intervals of all the trials. In the twin noise condition the same noise sample was used in the two intervals of a trial, but a new sample was generated for each trial. Fixed noise conditions usually resulted in lower thresholds than twin noise. Template learning models are presented that attribute this advantage of fixed over twin noise either to fixed memory templates' reducing uncertainty by incorporation of the noise or to the introduction, by the learning process itself, of more variability in the twin noise condition. Quantitative predictions of the template learning process show that it contributes to the accelerating nonlinear increase in performance with signal amplitude at low signal-to-noise ratios.
Document ID
20040142043
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Beard, B. L.
(NASA Ames Research Center Moffett Field CA United States)
Ahumada, A. J. Jr
Watson, A. B.
Date Acquired
August 22, 2013
Publication Date
March 1, 1999
Publication Information
Publication: Journal of the Optical Society of America. A, Optics, image science, and vision
Volume: 16
Issue: 3
ISSN: 1084-7529
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
NASA Center ARC
NASA Discipline Space Human Factors

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