Veridicality of three-dimensional shape perception predicted from amplitude spectra of natural textures.
We show that the amplitude spectrum of a texture pattern, regardless of its phase spectrum, can be used to predict whether the pattern will convey the veridical three-dimensional (3-D) shape of the surface on which it lies. Patterns from the Brodatz collection of natural textures were overlaid on a flat surface that was then corrugated in depth and projected in perspective. Perceived ordinal shapes, reconstructed from a series of local relative depth judgments, showed that only about a third of the patterns conveyed veridical shape. The phase structure of each pattern was then randomized. Simulated concavities and convexities were presented for both the Brodatz and the phase-randomized patterns in a global shape identification task. The concordance between the shapes perceived from the Brodatz patterns and their phase-randomized versions was 80-88%, showing that the capacity for a pattern to correctly convey concavities and convexities is independent of phase information and that the amplitude spectrum contains all the information required to determine whether a pattern will convey veridical 3-D shape. A measure of the discrete oriented energy centered on the axis of maximum curvature was successful in identifying textures that convey veridical shape.
Li
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SUNY State College of Optometry, New York, New York 10036, USA. ali@sunyopt.edu
Zaidi
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D015350:Contrast Sensitivity / Q000502:physiology*; D003867:Depth Perception / Q000502:physiology*; D005544:Forecasting; D005556:Form Perception / Q000502:physiology*; D006801:Humans; D008960:Models, Psychological; D010775:Photic Stimulation / Q000379:methods; D011897:Random Allocation; D014796:Visual Perception / Q000502:physiology*