Beginning with his doctoral dissertation in 1950 which introduced the study of event perception and the application of vector analysis to perception, Gunnar Johansson has been a seminal figure in the field of perception. His work on biomechanical motion in the 1970s challenged conventional notions and stimulated great interest among experimental psychologists and students of machine vision. In 1989 Johansson published his latest theoretical synthesis, the optic sphere theory, an innovative conceptualization that goes beyond his earlier proposals.

This volume presents -- for the first...