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Spatial-frequency spectrum of patterns changes the visibility of spatial-phase differencesIt is shown that spatial-frequency components over a 4-octave range affected the visibility of spatial-phase differences. Contrast thresholds were measured for discrimination between two (+45- and -45-deg) spatial phases of a sinusoidal test grating added to a background grating. The background could contain one or several sinusoidal components, all in 0-deg phase. Phase differences between the test and the background were visible at lower contrasts when test and background frequencies were harmonically related than when they were not, when test and background frequencies were within 1 octave than when they were farther apart, when the fundamental frequency of the background was low than when it was high, and for some discriminations more than for others, after practice. The visibility of phase differences was not affected by additional components in the background if the fundamental and difference frequencies of the background remained unchanged. Observers' reports of their strategies gave information about the types of attentive processing that were used to discriminate phase differences. Attentive processing facilitated phase discrimination for multifrequency gratings spanning a much wider range of spatial frequencies than would be possible by using only local preattentive processing. These results were consistent with the visibility of phase differences being processed by some combination of even- and odd-symmetric simple cells tuned to a wide range of different spatial frequencies.
Document ID
19850057687
Document Type
Reprint (Version printed in journal)
Authors
Lawton, T. B.
(California Institute of Technology, Jet Propulsion Laboratory, Pasadena; California, University Santa Barbara, CA, United States)
Date Acquired
August 12, 2013
Publication Date
July 1, 1985
Publication Information
Publication: Optical Society of America, Journal, A: Optics and Image Science
Volume: 2
ISSN: 0740-3232
Subject Category
Behavioral Sciences
Distribution Limits
Public
Copyright
Other
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