The role of spatial phase in texture segmentation and contour integration.
It has been recently argued that the visual system possesses just two phase "detector" mechanisms, namely, +cosine and -cosine (P. C. Huang, F. A. Kingdom, & R. F. Hess, 2006). This suggests rather limited access to the rich distribution of receptive field phase that neurophysiologists tell us are represented in the different response profiles of striate simple cells. Whereas that study has suggested that striate receptive field phase is not directly available to perception for the detection/discrimination of localized stimuli, here we investigate whether such information might be used in more integrative striate or extrastriate functions such as texture segregation or contour integration. Specifically, given that simple cells have different local absolute phase response profiles, we ask whether a network of simple cells with similar phase preferences interact in such a way as to extract textures, contours, or both based on phase alone. Two novel texture segmentation experiments and one contour integration experiment were carried out with the intention of providing an answer to the question of how useful is local absolute spatial phase for texture segmentation and contour integration. The results support the possibility of two phase mechanisms (+/-cosine) for global texture segmentation, as well as for contour integration, when the elements that make up a given contour are orthogonal to contour paths.
Hansen
Bruce C
BC
McGill Vision Research Unit, Department of Ophthalmology, McGill University, Montréal, QC, Canada. bruce.hansen@mcgill.ca
Hess
Robert F
RF
D005556:Form Perception / Q000502:physiology; D006801:Humans; D008959:Models, Neurological; D009415:Nerve Net / Q000502:physiology; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011601:Psychophysics / Q000379:methods; D013028:Space Perception / Q000502:physiology*; D014793:Visual Cortex / Q000502:physiology*