MOTION BLUR AND MOTION SHARPENING IN THE HUMAN VISUAL-SYSTEM

The effect of motion sharpening upon blur discrimination thresholds wa s examined for a range of speeds and blur widths, Blur discrimination thresholds were measured for drifting edges whose blur was either phys ically or perceptually constant, Under conditions where edges were kep t at a constant physical blur width, discrimination thresholds rose as a function of speed as previously reported, However, when the perceiv ed blur of edges was held constant, discrimination performance was mor e-or-less constant for speeds up to at least 6.3 deg sec(-1). The resu lts indicate that the deterioration of blur discrimination performance with speed may be due to motion sharpening and not motion blur as has previously been suggested. The results are discussed in terms of a sc heme whereby a non-linearity in motion processing serves to sharpen mo ving edges, whilst the finite integration time of the system tends to smear them, (C) 1997 Elsevier Science Ltd.