Motion-contrast computation without directionally selective motion sensors.
The detection of relative motion, i.e., motion contrast, has been reported for motion-sensitive neurons in several vertebrate systems, yet the mechanism underlying motion-contrast sensitivity remains unknown. An algorithm for computing motion contrast directly from the moving intensity distribution is proposed. In this algorithm, the time-dependent intensity distribution of the visual space is convolved with a periodic function. For coherent motion, the resulting convolution integral reduces to a traveling wave of fixed amplitude, while incoherent motion causes the amplitude to oscillate. The frequency of the amplitude oscillation provides a measure of motion contrast. The algorithm is successful in reproducing tuning curves derived from measurements of motion-contrast sensitivity in avian tectum and primate middle temporal area.
Dellen
B K
BK
Department of Physics, Washington University, Saint Louis, Missouri 63130, USA.
Clark
J W
JW
Wessel
R
R
D000465:Algorithms; D000818:Animals; D001921:Brain / Q000502:physiology*; D003198:Computer Simulation; D006801:Humans; D008959:Models, Neurological; D009039:Motion Perception / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D010363:Pattern Recognition, Automated / Q000379:methods*; D014159:Transducers