SPATIAL SAMPLING OF MOTION - SEEING AN OBJECT MOVING BEHIND A PICKET FENCE

Spatially sampled motion (H. P. Snippe & J. J. Koenderink, 1994) leads to time-lagged correlations of luminance change at discrete spatial p ositions. Observers matched the perceived width of a bar whose motion path was sampled spatially to the width of a static bar; the width of the moving object was not directly observable. Observers did reasonabl y well on this task when the stimulus onset asynchrony (SOA) between a djacent samples was approximately 90 ms, but performance broke down co mpletely when the SOA was doubled. Performance improved considerably a s more samples became available, provided that these samples all fell along the same smooth motion path and were seen by the same eye. This spatiotemporal information in spatially sampled motion can specify the width of a moving object, but it is likely to be useful to observers only if the sampling preserves the impression of motion.