Andersen G J, Atchley P
Department of Psychology, University of California, Riverside 92521, USA.
Percept Psychophys. 1997 Apr;59(3):358-69. doi: 10.3758/bf03211903.
Five experiments were conducted to determine the importance of smoothness of the velocity field in detecting 3-D surfaces from optic flow. Subjects were presented with optic flow displays simulating either points positioned on a corrugated 3-D surface or points randomly positioned within a 3-D volume. The subject's task was to indicate whether or not the display appeared to be a 3-D surface. Smoothness of the velocity field was examined by systematically varying the speed of individual velocities in the flow field according to a Gaussian distribution with M = 0 and SD = sigma. Variations in frequency, amplitude, density, and surface complexity were also examined. Detection of the corrugated surfaces systematically declined with an increase in sigma. An increase in frequency of the corrugation for simple (single-frequency corrugation) surfaces resulted in a decrease in surface detection accuracy. Accuracy increased with an increase in density and amplitude for both simple and complex (multiple-frequency corrugation) surfaces. An analysis of the deformation of the displays predicted performance on the basis of human observers, providing further support for the importance of deformation for 3-D surface detection.
进行了五项实验，以确定速度场的平滑度在从光流中检测三维表面时的重要性。向受试者呈现模拟位于波纹状三维表面上的点或随机位于三维体积内的点的光流显示。受试者的任务是指出显示是否看起来是三维表面。通过根据均值M = 0和标准差SD = σ的高斯分布系统地改变流场中各个速度的速度来检查速度场的平滑度。还检查了频率、振幅、密度和表面复杂度的变化。随着σ的增加，对波纹状表面的检测系统性下降。对于简单（单频波纹）表面，波纹频率的增加导致表面检测精度降低。对于简单和复杂（多频波纹）表面，精度随着密度和振幅的增加而提高。对显示变形的分析基于人类观察者预测了性能，为变形对三维表面检测的重要性提供了进一步支持。
