The dimensionality of texture-defined motion: a single channel theory
The dimensionality of texture-defined motion: a single channel theory
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DOI：
10.1016/0042-6989(93)90253-s
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发表时间：
1993-03
期刊：
影响因子：
1.8
通讯作者：
P. Werkhoven;G. Sperling;C. Chubb
中科院分区：
文献类型：
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作者：
P. Werkhoven;G. Sperling;C. Chubb
我们检查纹理属性所带来的表观运动。纹理刺激由一系列不同空间频率和幅度的光栅斑块组成。帧之间的相位是随机的，以确保直接应用于刺激亮度的一阶运动机制不会系统地参与。我们使用模糊视在运动显示，其中由交替的纹理 s（标准）和纹理 v（变量）块定义的异质运动路径与仅由纹理 s 块定义的同质运动路径竞争。我们的结果支持纹理运动的一维（单通道）模型，其中运动强度是根据刺激的单个空间变换（活动变换）计算的。通过该活动变换分配给时空点的值与局部纹理的调制幅度成正比，与局部空间频率（在检查的空间频率范围内）成反比。活动变换被建模为应用于刺激对比度的低通空间滤波器的校正输出。我们的数据进一步表明，纹理 s 的块和纹理 v 的块之间的纹理定义运动的强度与 s 和 v 的活动的乘积成正比。在我们的数据中证实的该模型的一个强烈违反直觉的预测是，不同纹理的块之间的运动可能比相似纹理的块之间的运动更强（例如，低对比度、低频纹理 l 的块和高对比度、高频纹理 h 的块之间的运动可以强于相似纹理 h 的块之间的运动）。
We examine apparent motion carried by textural properties. The texture stimuli consist of a sequence of grating patches of various spatial frequencies and amplitudes. Phases are randomized between frames to insure that first-order motion mechanismsdirectlyapplied to stimulusluminanceare not systematically engaged. We use ambiguous apparent motion displays in which a heterogeneous motion path defined by alternating patches of texture s (standard) and texture v (variable) competes with a homogeneous motion path defined solely by patches of texture s. Our results support a one-dimensional (single-channel) model of motion-from-texture in which motion strength is computed from a single spatial transformation of the stimulus—anactivitytransformation. The value assigned to a point in space-time by this activity transformation is directly proportional to the modulation amplitude of the local texture and inversely proportional to local spatial frequency (within the range of spatial frequencies examined). The activity transformation is modeled as the rectified output of a low-pass spatial filter applied to stimuluscontrast. Our data further suggest that thestrengthof texture-defined motion between a patch of texture s and a patch of texture v is proportional to the product of the activities of s and v. A strongly counterintuitive prediction of this model borne out in our data is that motion between patches of different texture can be stronger than motion between patches of similar texture (e.g. motion between patches of a low contrast, low frequency texture l and patches of high contrast, high frequency texture h can be stronger than motion between patches of similar texture h).