Real-time generation of random-element motion displays

Random-element motion patterns for visual research, in which a set of the elements are shifted uniformly on successive exposures, can be generated in real time on a CRT display, using a relatively low-cost, commercially available display processor (Sigma QVEC). The software achieves economy of time by not rewriting large amounts of the display file for each exposure. Instead it changes only the “chaining addresses” that determine the order in which strips of the display are arranged. Further features of the hardware and software are described.