Erkelens Casper J
Helmholtz Institute, Utrecht University, Utrecht, The Netherlands.
J Vis. 2013 Nov 14;13(13):16. doi: 10.1167/13.13.16.
One of the striking features of vision is that we can experience depth in two-dimensional images. Since the Renaissance, artists have used linear perspective to create sensations of depth and slant. What is not known is how the brain measures linear perspective information from the retinal image. Here, an experimental technique and geometric computations were used to isolate slant related to linear perspective from slant induced by other cues. Grid stimuli, designed to induce strong impressions of slant, were sufficiently simple to allow accurate predictions on the basis of numeric computations. Measurement of slant about the vertical axis as functions of slant depicted on the screen and slant of the screen relative to the observer showed that linear perspective explained 95% of the slant judgments. Precision and accuracy of the judgments suggest a neural substrate that is able to make highly accurate comparisons between orientations of lines imaged at different retinal locations. The neural basis of slant from the linear perspective has not yet been clarified. Long-range connections in V1, however, and cells in V2, V4, lateral occipital cortex, and caudal intraparietal sulcus have features that suggest an involvement in slant perception.
视觉的一个显著特征是我们能够在二维图像中体验到深度。自文艺复兴以来，艺术家们一直使用线性透视来营造深度和倾斜的感觉。目前尚不清楚的是大脑如何从视网膜图像中测量线性透视信息。在这里，一种实验技术和几何计算被用于将与线性透视相关的倾斜与其他线索引起的倾斜区分开来。为了产生强烈的倾斜印象而设计的网格刺激足够简单，能够基于数值计算进行准确预测。将相对于垂直轴的倾斜度作为屏幕上描绘的倾斜度以及屏幕相对于观察者的倾斜度的函数进行测量，结果表明线性透视解释了95%的倾斜度判断。这些判断的精度和准确性表明存在一种神经基质，它能够在不同视网膜位置成像的线条方向之间进行高度精确的比较。从线性透视角度来看，倾斜的神经基础尚未阐明。然而，V1中的长程连接以及V2、V4、外侧枕叶皮层和尾侧顶内沟中的细胞具有一些特征，表明它们参与了倾斜感知。
