Co-occurrence of luminance and chromatic edges does not always result in suppressed perception of depth from shading
Co-occurrence of luminance and chromatic edges does not always result in suppressed perception of depth from shading
复制标题
亮度和色彩边缘的共现并不总是导致阴影深度感知受到抑制
DOI：
10.1167/11.11.348
复制
发表时间：
2011
影响因子：
1.8
通讯作者：
Clery S
中科院分区：
文献类型：
--
作者：
Clery S
正弦亮度光栅可以看作是具有一系列深度波纹的表面。颜色信息可以改变波纹的感知深度：Kingdom的“色差效应”。他发现，与亮度正弦波正交的彩色正弦波增强了亮度定义波纹的感知深度，而对齐的彩色正弦波抑制了深度。对此提出的一个原因是，在自然界中，纯粹的亮度变化很可能是由于阴影或阴影造成的；由于反射率的变化，亮度和色度的变化可能同时发生。在我们的研究中，通过色度正弦和亮度正弦的简单组合来探索阴影的深度感知。刺激包括一个亮度和一个彩色正弦波（每个0.75 cpd），或具有相同或正交的方向。观察者被要求在随机的点立体图中，将亮度波纹中感知到的深度幅度与圆形深度基座（直径2度）的深度幅度相匹配。正如颜色阴影效应所预测的那样，我们发现在正交条件下，深度确实随着刺激中颜色或亮度对比度的增加而增加，尽管在我们的14个池中效果的强度有很大的变化na&ıuml；参与者。当色度和亮度正弦波对齐时，我们的一些观察者报告说，随着色度对比度的增加，预期的感知深度减少。然而，大约三分之一的参与者报告说，感知深度反而增加了。并不是所有的参与者都表现出亮度和颜色边缘的共同出现是由于反射率的变化（即材料颜色的变化）。这挑战了色彩阴影效果背后的基本逻辑。基于色度和亮度通道之间掩蔽的更简单的论点可以为感知的深度变化提供另一种解释。
A sinusoidal luminance grating can be perceived as a surface with a series of depth corrugations. Chromatic information can alter the perceived depth of the corrugations: Kingdom's ‘colour-shading effect’. He found that a chromatic sinusoid, orthogonal to a luminance sinusoid, enhances the perceived depth of the luminance-defined corrugation, whilst aligned chromatic sinusoids suppress the depth. One reason put forward for this is that, in the natural world, pure luminance change is likely due to shadow or shading; the co-occurrence of luminance and chromatic change is likely due to reflectance change. In our study, depth perception from shading was explored with a simple combination of chromatic and luminance sinusoids. The stimuli consisted of a luminance and a chromatic sinusoid (each 0.75 cpd), either having the same or orthogonal orientation. Observers were asked to match the amplitude of depth perceived in the luminance corrugation with that of a circular depth pedestal (diameter 2 deg), in a random dot stereogram. As the colour-shading effect predicts, we found for the orthogonal condition, that depth did increase as either chromatic or luminance contrast was increased in the stimuli, although there were large variations in the strength of the effect across our pool of 14 na&ıuml; ve participants. When the chromatic and luminance sinusoids were aligned, some of our observers reported the expected decrease in perceived depth as chromatic contrast was increased. However, around one third of our participants reported instead an increase in the perceived depth. Not all of our participants behave as if the co-occurrence of a luminance and chromatic edge is due to a reflectance change (ie a change in the material colour). This challenges the basic logic behind the colour-shading effect. Simpler arguments, based on masking between chromatic and luminance channels could provide an alternative explanation for the perceived depth variation.