Second-order spatial frequency and orientation channels in human vision
نویسندگان
چکیده
منابع مشابه
Second-order spatial frequency and orientation channels in human vision
We compared the number of spatial frequency and orientation mechanisms underlying first- versus second-order processing by measuring discrimination at detection threshold for first- and second-order Gabors to determine the smallest difference in spatial frequency and orientation that permits accurate discrimination at threshold. For second-order gratings, the number of channels is the same as f...
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The segregation of texture patterns may be carried out by a set of linear spatial filters (to enhance one of the constituent textures), a nonlinearity (to convert the higher contrast of response to that constituent to a higher mean response), and finally subsequent ("second-order") linear spatial filters (to provide a strong response to the texture-defined edge itself). In this paper, the prope...
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Previous work showed that adapting to low spatial frequency gratings (below 1.5 cycles/degree) may cause maximal spatial adaptation at a significantly higher spatial frequency. It has been suggested that there are no adaptable spatial-frequency channels tuned to below 1.5 c/deg. Contrary to this view, we found that adaptation and masking with low spatial frequencies (0.12-1.0 c/deg) produced ma...
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The detectability of a 9·0 c/deg sinusoidal grating was measured against various backgrounds: A blank field, a 3·0 c/deg grating and a 1·8 c/deg grating. Detection of the 9·0 c/deg grating was facilitated by suprathreshold 3·0 c/deg grating backgrounds (3·0 and 9·0 c/deg are first and third harmonics), but was not facilitated by 1·8 c/deg grating backgrounds (first and fifth harmonics). The res...
متن کاملIs there opponent-orientation coding in the second-order channels of pattern vision?
Is there opponency between orientation-selective processes in pattern perception, analogous to opponency between color mechanisms? Here we concentrate on possible opponency in second-order channels. We compare several possible second-order structures: SIGN-opponent-only channels in which there is no opponency between orientations (also called complex channels or filter-rectify-filter mechanisms...
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ژورنال
عنوان ژورنال: Vision Research
سال: 2006
ISSN: 0042-6989
DOI: 10.1016/j.visres.2006.01.028