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Elena Gheorghiu, Frederick Kingdom; Luminance-contrast properties of texture-shape and of texture-surround suppression of contour-shape . Journal of Vision 2016;16(12):245. doi: https://doi.org/10.1167/16.12.245.
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© ARVO (1962-2015); The Authors (2016-present)
Aim: Contour shape processing is selective to luminance polarity (Gheorghiu & Kingdom, 2006, Vis.Res) and surround textures inhibit the processing of contour shapes (Gheorghiu & Kingdom, 2014, Vis.Res). Energy models of texture processing suggest that textures are not selective to luminance polarity (Malik & Perona, 1990). Here we investigate the nature of first-order inputs to texture-shape and texture-surround suppression by examining whether texture-shape itself and texture-surround suppression of contour shape are selective to luminance-polarity and the magnitude of luminance contrast. Method: To test for luminance-polarity selectivity, textures and contours were constructed from strings of elongated Gaussian blobs that were either 'bright' or 'dark'. To test for selectivity to the magnitude of luminance contrast, textures and contours were constructed from strings of Gabors. Observers adapted to pairs of either sinusoidal-shaped textures made of a series of contours arranged in parallel or single contours that differed in shape-frequency, and the resulting shifts in the apparent shape-frequencies of texture-test or contour-test pairs were measured. Texture-surround adaptors consisted of a central contour and a surround made of parallel contours. We compared the after-effects between: (a) texture-adaptors and tests of same versus different luminance polarity; (b) texture-surround/central-contour adaptors of same versus different luminance polarity (or magnitude of luminance contrast), with contour-tests of same luminance-polarity (or magnitude of luminance contrast) as central-contour adaptor. Results: (i) Texture-shape processing in textures made of elongated Gaussian blobs is selective for luminance-polarity. (ii) Texture-surround suppression of contour-shape processing shows weak selectivity for luminance polarity. (iii) Texture-surround suppression of contour-shape is stronger for equal-in-contrast center and surround, and more prominent for higher than lower surround-to-center contrast ratios. Conclusion: Texture-shape processing depends on on-off luminance polarity channel interactions and texture-surround suppression of contour shape is selective to both polarity and the magnitude of luminance contrast.
Meeting abstract presented at VSS 2016
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