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Energy model for contrast detection: spatial-frequency and orientation selectivity in grating summation.

V Manahilov·W A Simpson
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Abstract

Models of spatial vision usually assume a "front-end" of spatial-frequency and orientation selective channels. Subthreshold-summation studies have provided some of the strongest support for this notion. We applied a single-channel energy model and a multiple-channels probability-summation model to explore subthreshold-summation phenomena. We measured the contrast thresholds for detection of two superimposed Gabor patches as a function of the spatial-frequency and orientation difference between the components. The stimuli were centred 7.5 deg above the fixation point and were windowed by a Gaussian function with one of two different spatial spreads. We have shown that the spatial-frequency and orientation selectivity in subthreshold summation of Gabor patches is determined by the similarity (cross-correlation) between the stimulus components. A single-channel energy model as well as a multiple-channels probability-summation model could explain the summation data.

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Contrast SensitivityHumansMathematical ComputingModels, BiologicalNormal DistributionOrientationSpace PerceptionJournal ArticleResearch Support, Non-U.S. Gov't

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V Manahilov, W A Simpson. 2001. Energy model for contrast detection: spatial-frequency and orientation selectivity in grating summation.. https://doi.org/10.1016/s0042-6989(01)00034-7

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