Abstract

It was reported that texture segregation in the space of the IID texture varying in mean luminance and contrast is mediated by two mechanisms: (1) texture luminance-sensing mechanism, and (2) one which senses the combined property of texture luminance and contrast (Nam, 1995, 1999). This paper studies the characteristics of these mechanisms in texture segregation in adopting three different sizes of texture elements. Specifically, it focuses on how texture luminance and contrast are combined by the second mechanism. We measured the probability of discrimination for various pairs of textures in the IID space with three different texture element sizes. The size of texture elements was manipulated so that the sampling capacity of the mechanisms was systematically influenced. We observed that each threshold produced by two mechanisms was changed systematically in the opposite direction. It was suggested that the second mechanism consists of a single process with a combined property of texture luminance and contrast rather than a dual process which senses texture luminance and contrast separately, then combines these outputs on the next step. A negative half-wave rectification is proposed as a single process in texture segregation for the second mechanism.