Stereoscopic depth but not shape perception from second-order stimuli.

L R Ziegler; R F Hess

doi:10.1016/s0042-6989(98)00224-7

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Stereoscopic depth but not shape perception from second-order stimuli.

L R Ziegler·R F Hess

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Abstract

Depth can be seen using either linear (first-order) or non-linear (second-order) stereo micropatterns when, in the latter, contrast envelopes contain the disparity information. We examined whether a second-order mechanism can contribute to the perception of 3-D surface shape. Using a variety of different stimulus types, we show that for each, shape is easy to see with linear stimuli. Over a wide range of parameters however, none of our observers perceived shape, however faintly, from the non-linear stimuli. To explore why these elements failed, we simplified our stimulus to a step-edge in depth and measured performance while varying the number of elements. We show how performance declined when more than two non-linear elements were used. We discuss reasons for the limitation found for non-matching elements, including a dissociation for stereopsis between seeing surface shape and depth.

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Contrast Sensitivity Depth Perception Female Fixation, Ocular Form Perception Humans Male Pattern Recognition, Visual Psychophysics Rotation Vision Disparity Journal Article Research Support, Non-U.S. Gov't

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L R Ziegler, R F Hess. 1999. Stereoscopic depth but not shape perception from second-order stimuli.. https://doi.org/10.1016/s0042-6989(98)00224-7

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