The threshold size of an object as a function of its speed has been determined, with the eyes fixed using seven different speeds from 55 to 600 cm/sec. The relationship is found to be linear and is given by the equation O=a+bV, where O is the threshold size in millimeters, V is the speed in centimeters per second, and a and b are constants characteristic of the individual. It is suggested that the spatio-temporal pattern at the psychovisual cortex is in some way responsible for the observed function.
BALRAJ BHATIA and C. A. VERGHESE, "Threshold Size of a Moving Object as a Function of its Speed," J. Opt. Soc. Am. 54, 948-950 (1964)