Reid R C, Shapley R
Rockefeller University, New York, NY 10021.
Vision Res. 1988;28(1):115-32. doi: 10.1016/0042-6989(88)90013-2.
Two mechanisms of brightness perception (1) brightness induction by local contrast and (2) assimilation, were examined for a variety of visual stimuli. Local contrast is the primary determinant of brightness perception, making objects appear brighter on a background of lower luminance and darker on a background of greater luminance. Assimilation is the opposite effect, whereby objects on a brighter (but not necessarily more luminant) background appear brighter or on a dark background appear darker. We have compared the relative strength of the two effects using stimuli which permit them to be studied separately. Brightness induction by local contrast is quantitatively stronger in all situations. Further, the strength of assimilation is strongly dependent on spatial parameters in the visual scene. These results are shown to be true both for simple visual stimuli as well as for complicated Mondrian-like patterns. The Retinex theory of brightness perception predicts that the two effects are equal. Our results show a range of relative strengths (assimilation vs brightness induction due to contrast) from 0.59 to 0.63 at 5' down to 0.34 at 43'.
针对多种视觉刺激，研究了两种亮度感知机制：（1）局部对比度引起的亮度诱导和（2）同化作用。局部对比度是亮度感知的主要决定因素，使得物体在较低亮度背景上显得更亮，而在较高亮度背景上显得更暗。同化作用则是相反的效果，即物体在较亮（但不一定是亮度更高）的背景上显得更亮，或者在较暗背景上显得更暗。我们使用能够分别研究这两种效果的刺激，比较了它们的相对强度。在所有情况下，局部对比度引起的亮度诱导在数量上都更强。此外，同化作用的强度强烈依赖于视觉场景中的空间参数。这些结果对于简单视觉刺激以及复杂的类似蒙德里安图案的图案都成立。视网膜皮层亮度感知理论预测这两种效果是相等的。我们的结果显示，相对强度范围（同化作用与对比度引起的亮度诱导之比）在5'时为0.59至0.63，在43'时降至0.34。
