Rokers Bas, Yuille Alan, Liu Zili
Department of Psychology, University of California, Los Angeles, USA.
Vision Res. 2006 Jul;46(15):2375-87. doi: 10.1016/j.visres.2006.01.032. Epub 2006 Mar 15.
An ellipse rotating in the image plane can produce several different percepts. The two-dimensional (2D) percepts are either a rotating rigid ellipse or a constantly deforming non-rigid ellipse. The 3D percept is a rotating rigid circular disk that is tilted relative to the image plane. Stimuli that generate 3D percepts based on purely 2D rotational motion are known as stereokinetic stimuli. We examined the 3D percepts generated by the rotating ellipse stimulus. In theory, the motion of the 3D percept cannot be reliably inferred based on the 2D stimulus. When we quantitatively estimated observers' perceived motion, however, we found that the perceived motion was nearly identical across observers. These results suggest that all observers had similar 3D percepts. We assumed that given the 2D rotating ellipse stimulus the visual system generates a rigid 3D percept that is as slow and smooth as possible. The percepts predicted by these assumptions closely matched the experimental data. These findings suggest that perceptual ambiguity in stereokinetic stimuli is resolved using slow and smooth motion assumptions.
在图像平面中旋转的椭圆可以产生几种不同的感知。二维（2D）感知要么是一个旋转的刚性椭圆，要么是一个不断变形的非刚性椭圆。三维（3D）感知是一个相对于图像平面倾斜的旋转刚性圆盘。基于纯二维旋转运动产生3D感知的刺激被称为立体运动刺激。我们研究了由旋转椭圆刺激产生的3D感知。理论上，无法根据二维刺激可靠地推断出三维感知的运动。然而，当我们定量估计观察者的感知运动时，我们发现不同观察者的感知运动几乎相同。这些结果表明，所有观察者都有相似的3D感知。我们假设，在给定二维旋转椭圆刺激的情况下，视觉系统会生成一个尽可能缓慢和平滑的刚性3D感知。这些假设所预测的感知与实验数据密切匹配。这些发现表明，立体运动刺激中的感知模糊性是通过缓慢和平滑的运动假设来解决的。
