de Vries S C, Kappers A M, Koenderink J J
Utrecht Biophysics Research Institute, Department of Medical and Physiological Physics, The Netherlands.
Vision Res. 1994 Sep;34(18):2409-23. doi: 10.1016/0042-6989(94)90285-2.
We report on the ability of human observers to discriminate local second-order shape of quadratic stereo-defined surfaces. Local second-order shape can be specified by two parameters: the curvedness (a scale-dependent quantity describing overall curvature of a shape) and the shape index (a scale-independent quantity describing the shape's appearance). We measured shape index discrimination thresholds of shapes subject to attitude and curvedness transformations. Results show that neither slant nor curvedness manipulations affect or bias observers' judgements of surface shape. Furthermore, ideal detector simulations show that observers do not perform optimally: they do not exploit all available information.
我们报告了人类观察者辨别二次立体定义表面局部二阶形状的能力。局部二阶形状可由两个参数指定：曲率（一个与尺度相关的量，描述形状的整体曲率）和形状指数（一个与尺度无关的量，描述形状的外观）。我们测量了形状在姿态和曲率变换下的形状指数辨别阈值。结果表明，倾斜和曲率操作均不会影响或偏向观察者对表面形状的判断。此外，理想探测器模拟表明，观察者并未达到最佳表现：他们没有利用所有可用信息。
