The effects of amplitude-spectrum statistics on foveal and peripheral discrimination of changes in natural images, and a multi-resolution model.
Psychophysical thresholds were measured for discriminating small changes in spatial features of naturalistic scenes (morph sequences), for foveal and peripheral vision, and under M-scaling. Sensitivity was greatest for scenes with near natural Fourier amplitude slope, perhaps implying that human vision is optimised for natural scene statistics. A low-level model calculated differences in local contrast between pairs of images within a few spatial frequency channels with bandwidth like neurons in V1. The model was "customised" to each observer's contrast sensitivity function for sinusoidal gratings, and it could replicate the "U-shaped" relationships between discrimination threshold and spectral slope, and many differences between picture sets and observers. A single-channel model and an ideal-observer analysis both failed to capture the U-shape.
Párraga
C A
CA
Department of Experimental Psychology, University of Bristol, 8 Woodland Road, Bristol, BS8 1TN, UK. alej.parraga@bristol.ac.uk
Troscianko
T
T
Tolhurst
D J
DJ
D015350:Contrast Sensitivity / Q000502:physiology; D004056:Differential Threshold / Q000502:physiology; D004192:Discrimination, Psychological / Q000502:physiology*; D005584:Fovea Centralis / Q000502:physiology*; D006801:Humans; D008959:Models, Neurological; D008960:Models, Psychological; D010775:Photic Stimulation / Q000379:methods; D011594:Psychometrics; D011601:Psychophysics; D014794:Visual Fields / Q000502:physiology