Harada Shinya, Mitsudo Hiroyuki
Graduate School of Human-Environment Studies, Kyushu University, Fukuoka, Japan.
Perception. 2017 Jul;46(7):860-873. doi: 10.1177/0301006616687319. Epub 2017 Jan 10.
Depth contrast is a stereoscopic visual phenomenon in which the slant of an element is affected by that of adjacent elements. Normalization has been proposed to be a possible cause of depth contrast, but it is still unclear how depth contrast involves normalization. To address this issue, we devised stereograms consisting of a vertical test line accompanied by several inducer lines, like a three-dimensional variation of the well-known Müller-Lyer configuration. The inducer lines had horizontal binocular disparities that defined a stereoscopic slant about a horizontal axis with respect to the endpoints of the test line. The observer's task was to adjust the slant of the test line about a horizontal axis until it appeared subjectively vertical. The results of two psychophysical experiments found that slant settings were affected by the slant of local inducers, but not by the overall slant of the whole stimulus. These results suggest that, at least for line patterns, the stereo system normalizes depth locally.
深度对比是一种立体视觉现象，其中一个元素的倾斜度会受到相邻元素倾斜度的影响。归一化被认为是深度对比的一个可能原因，但深度对比如何涉及归一化仍不清楚。为了解决这个问题，我们设计了由一条垂直测试线和几条诱导线组成的立体图，类似于著名的缪勒-莱尔图形的三维变体。诱导线具有水平双目视差，相对于测试线的端点定义了围绕水平轴的立体倾斜度。观察者的任务是调整测试线围绕水平轴的倾斜度，直到它主观上看起来垂直。两项心理物理学实验的结果发现，倾斜度设置受局部诱导线倾斜度的影响，而不受整个刺激的整体倾斜度的影响。这些结果表明，至少对于线条图案，立体视觉系统在局部对深度进行归一化。
