Duke Philip A, Howard Ian P
Centre for Vision Research, York University, Toronto, Ontario, Canada.
J Vis. 2012 Aug 17;12(8):10. doi: 10.1167/12.8.10.
A textured surface appears slanted about a vertical axis when the image in one eye is horizontally enlarged relative to the image in the other eye. The surface appears slanted in the opposite direction when the same image is vertically enlarged. Two superimposed textured surfaces with different horizontal size disparities appear as two surfaces that differ in slant. Superimposed textured surfaces with equal and opposite vertical size disparities appear as a single frontal surface. The vertical disparities are averaged. We investigated whether vertical size disparities are averaged across two superimposed textured surfaces in different depth planes or whether they induce distinct slants in the two depth planes. In Experiment 1, two superimposed textured surfaces with different vertical size disparities were presented in two depth planes defined by horizontal disparity. The surfaces induced distinct slants when the horizontal disparity was more than ±5 arcmin. Thus, vertical size disparities are not averaged over surfaces with different horizontal disparities. In Experiment 2 we confirmed that vertical size disparities are processed in surfaces away from the horopter, so the results of Experiment 1 cannot be explained by the processing of vertical size disparities in a fixated surface only. Together, these results show that vertical size disparities are processed separately in distinct depth planes. The results also suggest that vertical size disparities are not used to register slant globally by their effect on the registration of binocular direction of gaze.
当一只眼睛中的图像相对于另一只眼睛中的图像在水平方向上放大时，有纹理的表面看起来围绕垂直轴倾斜。当同一图像在垂直方向上放大时，表面看起来向相反方向倾斜。两个具有不同水平尺寸差异的叠加纹理表面看起来是两个倾斜度不同的表面。具有相等且相反垂直尺寸差异的叠加纹理表面看起来是一个单一的正面表面。垂直差异被平均。我们研究了垂直尺寸差异是在不同深度平面上的两个叠加纹理表面之间被平均，还是它们在两个深度平面上诱导出不同的倾斜度。在实验1中，在由水平差异定义的两个深度平面上呈现了两个具有不同垂直尺寸差异的叠加纹理表面。当水平差异大于±5角分时，这些表面诱导出不同的倾斜度。因此，垂直尺寸差异不会在具有不同水平差异的表面之间被平均。在实验2中，我们证实了垂直尺寸差异在远离双眼单视界的表面中被处理，所以实验1的结果不能仅通过在固定表面中处理垂直尺寸差异来解释。总之，这些结果表明垂直尺寸差异在不同的深度平面中被分别处理。结果还表明，垂直尺寸差异不会通过它们对双眼注视方向登记的影响来全局登记倾斜度。
