Department of Psychology.
Faculty of Social Sciences and Humanities, Sheffield Hallam University.
J Exp Psychol Hum Percept Perform. 2019 Nov;45(11):1470-1483. doi: 10.1037/xhp0000675. Epub 2019 Sep 26.
Surface reflectance and illumination level, which are confounded in the retinal image, must be disentangled by the visual system and a theory of lightness must explain how. Thus, a theory of surface lightness should also be a theory of perceived illumination and describe the relationship between them. Perceived illumination and perceived gray values have been measured using a new technique. Looking into a vision tunnel, observers saw two square apertures in the far wall, each revealing a patch of wall composed of two shades of gray. They adjusted the illumination level in one aperture to match that in the other. The stimuli placed in the apertures varied in luminance range, spatial frequency, and relative area. Results show that (a) illumination is matched for highest luminance (with no effect of spatial frequency). Combined with earlier findings that lightness is anchored by highest luminance, this supports Koffka's suggestion that lightness and perceived illumination are coupled in an invariant way. (b) Changes in the relative area of the light and dark shades produced complementary influences on perceived illumination and surface lightness. That is, when stimulus conditions evoke a conflict between anchoring the highest luminance at white and anchoring the largest area at white, enlarging the darker shade causes its lightness to increase and the perceived illumination to decrease by the same amount, further supporting Koffka. (c) These findings allow perceived illumination level to now be systematically incorporated into anchoring theory, which until this point has been solely a theory of surface lightness. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
表面反射率和照度在视网膜图像中是混淆的，必须由视觉系统解开，并且一个明度理论必须解释如何解开。因此，表面明度理论也应该是一个感知照度理论，并描述它们之间的关系。使用新技术测量了感知照度和感知灰度值。观察者通过视觉隧道观察到远处墙上的两个方孔，每个孔都显示出一块由两种灰度组成的墙斑。他们调整一个孔中的照度水平以使其与另一个孔中的照度水平相匹配。放置在孔中的刺激在亮度范围、空间频率和相对区域上有所不同。结果表明：(a) 照度是根据最高亮度匹配的（没有空间频率的影响）。这与明度由最高亮度锚定的早期发现相结合，支持了科夫卡的观点，即明度和感知照度以不变的方式耦合。(b) 亮暗区相对面积的变化对感知照度和表面明度产生互补影响。也就是说，当刺激条件引起将最高亮度锚定在白色和将最大面积锚定在白色之间的冲突时，增大较暗区域会使其明度增加，同时感知照度以相同的量减少，这进一步支持了科夫卡的观点。(c) 这些发现使得感知照度水平现在可以系统地纳入到锚定理论中，而在此之前，锚定理论仅仅是一个表面明度理论。
