Trueswell J C, Hayhoe M M
Center for Visual Science, University of Rochester, NY 14627.
Vision Res. 1993 Feb;33(3):313-28. doi: 10.1016/0042-6989(93)90088-e.
Two studies are presented which explore how depth information is determined from conditions of transparency and whether this information combines with other depth information to determine the segmenting of motion information on the basis of likely surface boundaries. The first study explored how binocular disparity combines with monocular depth cues associated with transparency to determine whether subjects see one or multiple surfaces in depth in static displays. When transparency provided a depth cue that was consistent with binocular disparity, depth discrimination thresholds were at normal levels. However, if transparency was inconsistent with the binocular disparity, depth discrimination thresholds were elevated, indicating that subjects had difficulty seeing distinct surfaces lying in separate depth planes. Moreover, threshold elevations were found to correspond to the reductions in contrast between the intersecting contours of the stimulus, suggesting that the strength of perceived depth from transparency is the result of attenuated responses from competing contrast sensitive T-junction mechanisms responsible for the detection of opaque occlusion. A second experiment explored whether the grouping of local motion signals relied on surface interpretations that result from the interaction of transparency and disparity. Surface interpretations were manipulated in moving plaids by combining transparent layering and binocular disparity to show that the motion arising from contours is grouped together (pattern motion) when these cues support the existence of a single surface, and is segregated (component motion) when they support separate surfaces. When these cues were consistent, only small disparity differences were required for the gratings to appear as separately moving surfaces. However, when they were inconsistent, greater disparities were required (about a factor of 2 greater). Taken together, these studies demonstrate that the grouping of local motion information is not resolved within the motion system alone. Information seemingly unrelated to motion processing, namely surface segmentation cues, is used to determine whether or not motion information arising from various contours is pooled together to determine a single motion.
本文介绍了两项研究，探讨了如何从透明度条件中确定深度信息，以及该信息是否与其他深度信息相结合，以基于可能的表面边界来确定运动信息的分割。第一项研究探讨了双眼视差如何与与透明度相关的单眼深度线索相结合，以确定受试者在静态显示中是否能看到一个或多个深度表面。当透明度提供与双眼视差一致的深度线索时，深度辨别阈值处于正常水平。然而，如果透明度与双眼视差不一致，深度辨别阈值会升高，这表明受试者难以看到位于不同深度平面的不同表面。此外，发现阈值升高与刺激相交轮廓之间对比度的降低相对应，这表明从透明度感知到的深度强度是负责检测不透明遮挡的竞争性对比敏感T型连接机制反应减弱的结果。第二项实验探讨了局部运动信号的分组是否依赖于透明度和视差相互作用产生的表面解释。通过结合透明分层和双眼视差，在移动的方格图案中操纵表面解释，结果表明，当这些线索支持单个表面的存在时，由轮廓产生的运动被归为一组（图案运动），而当它们支持不同表面时，运动则被分离（成分运动）。当这些线索一致时，光栅要呈现为单独移动的表面，只需要很小的视差差异。然而，当它们不一致时，则需要更大的视差（大约大2倍）。综上所述，这些研究表明，局部运动信息的分组并非仅在运动系统内得到解决。看似与运动处理无关的信息，即表面分割线索，被用于确定来自各种轮廓的运动信息是否被汇总在一起以确定单一运动。
