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Cassandra Diggiss, Frederick A. A. Kingdom; Edge-based versus region-based texture perception: does the task matter?. Journal of Vision 2013;13(9):45. doi: https://doi.org/10.1167/13.9.45.
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© ARVO (1962-2015); The Authors (2016-present)
Aim: Studies of texture segregation have suggested that some types of textures are processed by ‘edge-based’ and others by ‘region-based’ mechanisms (e.g. Wolfson & Landy, Vis. Res., 1998). On the other hand, studies using nominally ‘edge-based’ textures have found evidence for region-based processing when the task was to detect rather than to segregate the textures (Kingdom & Keeble, Vis. Res., 1996). Here we investigate directly whether the nature of the task determines if region-based or edge-based mechanisms are involved in texture perception. Method: Stimuli consisted of randomly positioned Gabor micropattern texture arrays with three types of modulation: orientation modulation (OM), contrast modulation (CM) and luminance modulation (LM). Each modulation type was defined by three types of waveforms: sine-wave (SN), square-wave (SQ) and cusped-wave (CS). The CS waveform was constructed by removing an equal-amplitude sine-wave from a square-wave. The SN textures had only smooth variations, whereas the SQ and CS waveforms had sharp texture edges, but with different texture energies. Subjects performed two tasks. In the detection task subjects selected which of two stimuli contained the modulation. In the discrimination task subjects indicated which of two textures with slightly different texture-bar orientations contained leftward-oriented bars. Results: At low texture spatial frequencies threshold amplitudes in the detection task followed the rule SQ <SN <CS, as would be expected if all the texture energy available was used for detection, and suggesting that the task was region-based. However, for the discrimination task the order was SQ similar to CS and both less than SN, suggesting that the texture edges were the more salient features. At medium and high texture spatial frequencies the two tasks produced comparable results. Conclusion: A change in the task from detection to discrimination can under some circumstances cause texture processing to switch from being region-based to edge-based.
Meeting abstract presented at VSS 2013
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