Erkelens C J, van de Grind W A
Department of Physics of Man, Utrecht Biophysics Research Institute, Universiteit Utrecht, The Netherlands.
Vision Res. 1994 Nov;34(22):2963-9. doi: 10.1016/0042-6989(94)90268-2.
We examine whether the rules of cyclopean visual direction, as expressed by Hering and others, correctly predict the percept of visual direction for structured visual stimuli. Theoretical inspection of the rules of cyclopean visual direction shows a paradox for the binocular visual directions of stimuli in which objects partly occlude each other. We investigate how the rules of cyclopean direction are violated during viewing of structured random-dot stereograms with different depth planes. The directions of monocular and binocular visual elements are determined in an alignment task. Subjects align a monocular/binocular slider with a monocular/binocular test line present in the random-dot stereograms. The results show that the available rules of cyclopean direction are not sufficient for human vision in this general situation. The available rules can only be used for alignment of two binocularly visible lines or two monocular lines presented to the same eye. Alignment in these cases is predicted by almost any set of rules that transforms visible lines to a cyclopean eye. Stimulus conditions, in which either one line is presented to one eye and the other line to the other eye or one line is presented to one eye and the other line to two eyes, provide a more critical test for validity of the cyclopean rules. Our results show that the rules of cyclopean direction fail to predict alignment precisely in these conditions. Inspection of the data shows that binocular alignment is achieved by alignment of two monocular lines presented to a single eye.
我们检验了由赫林等人提出的双眼视觉方向规则是否能正确预测结构化视觉刺激的视觉方向感知。对双眼视觉方向规则的理论审视表明，对于物体部分相互遮挡的刺激的双眼视觉方向存在一个悖论。我们研究了在观看具有不同深度平面的结构化随机点立体图时，双眼方向规则是如何被违反的。在对齐任务中确定单眼和双眼视觉元素的方向。受试者将单眼/双眼滑块与随机点立体图中出现的单眼/双眼测试线对齐。结果表明，在这种一般情况下，现有的双眼方向规则不足以解释人类视觉。现有的规则只能用于对齐两条双眼可见的线或呈现给同一只眼睛的两条单眼线。在这些情况下，几乎任何一组将可见线转换为双眼视觉的规则都能预测对齐情况。刺激条件，即一条线呈现给一只眼睛而另一条线呈现给另一只眼睛，或者一条线呈现给一只眼睛而另一条线呈现给两只眼睛，为双眼规则的有效性提供了更关键的测试。我们的结果表明，在这些条件下，双眼方向规则无法精确预测对齐情况。对数据的检查表明，双眼对齐是通过对齐呈现给单只眼睛的两条单眼线来实现的。
