Abstract
A texture consisting of elements all having the same orientation looks uniform despite the known presence of early sensory noise. To account for this paradox, we suggest that the visual system discounts the presence of its own noise, in the same way that it discounts normal amounts of optical blur in the retinal image. The mechanism for this discounting is a sensory threshold, which stops texture elements apparently departing from the texture mean unless they exceed a fixed threshold. We sought further evidence for this thresholding by measuring the just-noticeable difference (JND) in orientation variance between two textures as we varied the baseline (pedestal) variance present in both textures. We found the best discrimination when a small amount of variance was present in both textures, as would be predicted from a threshold.