Schlerf John, Domini Fulvio, Caudek Corrado
Department of Cognitive and Linguistic Sciences, Brown University, P.O. Box 1978, Providence, RI 02912, USA.
Vision Res. 2004 May;44(11):1079-91. doi: 10.1016/j.visres.2003.12.015.
Studies on binocular contrast sensitivity have predominantly focused on flat, two-dimensional (2D) gratings. The underlying hypothesis of such studies is that contrast sensitivity is determined at the early stages of visual processing and is not influenced by the process of three-dimensional (3D) shape recovery. However, it can be argued that contrast detection involves identifying changes in albedo of a 3D surface rather than strictly determining the presence of 2D luminance changes. In support of this hypothesis, in three experiments we found that the relative salience of oriented luminance modulations was affected by the disparity content of the stimuli, when the same luminance distribution was assigned to a flat surface or to a surface modulated in depth. In the first experiment, in particular, we found that the relative salience of an oriented luminance grating decreased when it could be interpreted as the shading produced by a Lambertian illumination, rather than a change in reflectance. In the other two experiments, moreover, we found that this effect was reduced when the frequency of the luminance modulation did not match the frequency of the stereo corrugation. These results are consistent with the idea that the appearance of a luminance distribution is affected by the perceived 3D properties of the surface on which the luminance distribution is located.
关于双眼对比敏感度的研究主要集中在平面二维（2D）光栅上。此类研究的基本假设是，对比敏感度是在视觉处理的早期阶段确定的，不受三维（3D）形状恢复过程的影响。然而，可以认为对比检测涉及识别3D表面反照率的变化，而不是严格确定2D亮度变化的存在。为支持这一假设，在三个实验中我们发现，当相同的亮度分布被赋予平面或深度调制的表面时，定向亮度调制的相对显著性受刺激的视差内容影响。特别是在第一个实验中，我们发现当一个定向亮度光栅可以被解释为由朗伯照明产生的阴影而不是反射率变化时，其相对显著性会降低。此外，在另外两个实验中，我们发现当亮度调制的频率与立体波纹的频率不匹配时，这种效应会减弱。这些结果与这样一种观点一致，即亮度分布的外观受亮度分布所在表面的感知3D属性影响。
