title: On-Off asymmetry in the perception of blur.
abstract: Natural images appear blurred when imperfect lens focus reduces contrast energy at higher spatial frequencies. Here, we present evidence that perceived blur also depends on asymmetries between On (positive contrast polarities) and Off (negative contrast polarities) image signals. Psychophysical matching experiments involving natural and artificial stimuli suggest that attenuating Off signals at high spatial frequencies results in increased perceptual blur relative to similar attenuations of On signals. Results support the notion that Off image signals play an important role in blur perception.
authors.affiliation: Department of Psychology, Graduate School of Humanities and Sociology, The University of Tokyo, Japan; JSPS Research Fellow, Japan. Electronic address: satoh@l.u-tokyo.ac.jp.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Sato
authors.affiliation: Department of Life Sciences, The University of Tokyo, Japan.
authors.forename: Isamu
authors.initials: I
authors.lastname: Motoyoshi
authors.affiliation: Department of Psychology, Graduate School of Humanities and Sociology, The University of Tokyo, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Sato
mesh_terms: D006801:Humans; D011601:Psychophysics; D012030:Refractive Errors / Q000503:physiopathology*; D015348:Vision, Binocular / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*
keywords: Blur; Contrast polarities