Baker C L, Hess R F
McGill Vision Research Unit, Department of Ophthalmology, McGill University, Montreal, Quebec, Canada.
Vision Res. 1998 May;38(9):1211-22. doi: 10.1016/s0042-6989(97)00283-6.
We have constructed "limited lifetime" stochastic motion stimuli using Gabor functions instead of dots, thereby controlling the local attributes of spatial frequency and orientation. Human psychophysical data for direction discrimination using these stimuli reveal two qualitatively distinct kinds of processing. For small displacements, direction discrimination performance as a function of displacement is scaled with spatial frequency in a manner consistent with a linear filtering motion mechanism. Motion perception for relatively large displacements is not directly related to the spatial frequency, and is consistent with a nonlinear process which signals motion of contrast envelopes.
我们使用伽柏函数而非点构建了“有限寿命”随机运动刺激，从而控制空间频率和方向的局部属性。使用这些刺激进行方向辨别的人类心理物理学数据揭示了两种性质不同的处理方式。对于小位移，作为位移函数的方向辨别性能与空间频率按比例缩放，其方式与线性滤波运动机制一致。相对大位移的运动感知与空间频率没有直接关系，并且与一种对对比度包络的运动进行信号传递的非线性过程一致。
