Anderson Barton L, Winawer Jonathan
University of New South Wales, School of Psychology, Sydney, New South Wales 2052, Australia.
Nature. 2005 Mar 3;434(7029):79-83. doi: 10.1038/nature03271.
The perception of surface albedo (lightness) is one of the most basic aspects of visual awareness. It is well known that the apparent lightness of a target depends on the context in which it is embedded, but there is extensive debate about the computations and representations underlying perceived lightness. One view asserts that the visual system explicitly separates surface reflectance from the prevailing illumination and atmospheric conditions in which it is embedded, generating layered image representations. Some recent theory has challenged this view and asserted that the human visual system derives surface lightness without explicitly segmenting images into multiple layers. Here we present new lightness illusions--the largest reported to date--that unequivocally demonstrate the effect that layered image representations can have in lightness perception. We show that the computations that underlie the decomposition of luminance into multiple layers under conditions of transparency can induce dramatic lightness illusions, causing identical texture patches to appear either black or white. These results indicate that mechanisms involved in decomposing images into layered representations can play a decisive role in the perception of surface lightness.
表面反照率（明度）的感知是视觉意识最基本的方面之一。众所周知，目标的表观明度取决于它所处的背景，但关于感知明度背后的计算和表征存在广泛争议。一种观点认为，视觉系统会明确地将表面反射率与它所处的主要照明和大气条件区分开来，生成分层的图像表征。最近的一些理论对这一观点提出了挑战，并断言人类视觉系统在没有将图像明确分割为多个层的情况下就能得出表面明度。在此，我们展示了新的明度错觉——迄今为止报道的最大的错觉——明确证明了分层图像表征在明度感知中可能产生的效果。我们表明，在透明条件下将亮度分解为多个层的计算会引发显著的明度错觉，使相同的纹理斑块看起来要么是黑色要么是白色。这些结果表明，将图像分解为分层表征所涉及的机制在表面明度的感知中可以起到决定性作用。
