Discrimination of planar surface slant from texture: human and ideal observers compared.
In order to quantify the ability of the human visual system to use texture information to perceive planar surface orientation, I measured subjects' ability to discriminate planar surface slant (angle away from the fronto-parallel) for a variety of different types of textures and in a number of different viewing conditions. I measured the subjects' discrimination performance as a function of surface slant, field of view size and surface texture structure. I compared the subjects' performance with that of ideal observers derived for each of the available texture cues--texel position, scaling and foreshortening. The results can be summarized by four points: (i) subjects' discrimination performance improves dramatically with increasing surface slant, tracking the performance of the ideal observers; (ii) subjects can integrate texture information over a large range of visual angles; (iii) comparisons between human subjects and ideal observers show that the human observers rely to some degree on foreshortening information; and (iv) similar comparisons show that in using foreshortening information, subjects rely to some extent on a prior assumption of isotropy.
Knill
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DC
Department of Psychology, University of Pennsylvania, Philadelphia 19104, USA. knill@cattell.psych.upenn.edu
D003463:Cues; D004192:Discrimination, Psychological; D006801:Humans; D008433:Mathematics; D008959:Models, Neurological; D010364:Pattern Recognition, Visual / Q000502:physiology*; D011594:Psychometrics; D012399:Rotation; D012684:Sensory Thresholds / Q000502:physiology; D014794:Visual Fields