title: Mach-band attenuation by adjacent stimuli: experiment and filling-in simulations.
abstract: Mach bands are illusory bright and dark bands seen where a luminance plateau meets a ramp, as in half shadows or penumbras. It has previously been shown that Mach bands are attenuated by placing stimuli, such as bars, nearby. It was shown in an experiment in which Mach-band attenuation for bar and Craik-O'Brien stimuli was compared that they are equally effective in attenuating Mach bands. The results suggest that the abrupt luminance transition of a stimulus adjacent to a ramp is responsible for the attenuation. The findings are interpreted in terms of a recent filling-in model of brightness perception and the results of computer simulations of stimuli are shown.
authors.affiliation: Programa de Engenharia de Sistemas e Computacao-COPPE Sistemas, Universidade Federal do Rio de Janeiro, Brazil. pessoa@cos.ufrj.br
authors.forename: L
authors.initials: L
authors.lastname: Pessoa
mesh_terms: D001288:Attention; D003198:Computer Simulation; D015350:Contrast Sensitivity; D004193:Discrimination Learning; D006801:Humans; D009903:Optical Illusions; D009949:Orientation; D010364:Pattern Recognition, Visual; D011601:Psychophysics