Simpson W A
Department of Psychology, York University, Ontario, Canada.
Perception. 1988;17(4):497-512. doi: 10.1068/p170497.
A simple scheme for deriving relative depth (time-to-collision, or TTC) from optic flow is developed in which the total flow is first sensed by unconnected motion (imperfect filter) sensors and then the rotational component is subtracted to yield the translational component. Only the latter component yields depth information. This scheme is contrasted with one where the TTC sensors respond only to the translational component at the initial registration of the flow (perfect filter sensors or looming detectors). The simple scheme predicts the results of three experiments on discrimination of TTC: discrimination thresholds are elevated if the objects withdraw from rather than approach the observer, thresholds are elevated if a rotational component is added to the flow, and the amount of threshold elevation resulting from the addition of a rotational component is reduced by prior adaptation to a pure rotational flow. These results confirm the simple model and disconfirm predictions based on the looming detector scheme.
开发了一种从光流中推导相对深度（碰撞时间，或TTC）的简单方案，其中总流首先由未连接的运动（不完美滤波器）传感器感知，然后减去旋转分量以得到平移分量。只有后者产生深度信息。该方案与另一种方案形成对比，在另一种方案中，TTC传感器在流的初始配准阶段仅对平移分量做出响应（完美滤波器传感器或逼近探测器）。该简单方案预测了关于TTC辨别的三个实验结果：如果物体远离而非靠近观察者，辨别阈值会升高；如果在流中添加旋转分量，阈值会升高；并且通过事先适应纯旋转流，因添加旋转分量而导致的阈值升高量会减少。这些结果证实了简单模型，并否定了基于逼近探测器方案的预测。
