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Dhanraj Vishwanath, Martin S. Banks; How viewing distance and object size affect judgments of shape in pictures. Journal of Vision 2006;6(6):264. doi: 10.1167/6.6.264.
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When viewing a picture from different distances, changes in the shape and orientation of depicted objects are often not perceived despite corresponding changes in the retinal image. For example, a slanted rectangular plane should appear to have a higher aspect ratio and a correspondingly higher slant when viewed at greater distances. We examined how perceptual judgments of shape varied with viewing distance. Observers judged the aspect ratio of a slanted rectangular plane in a depicted 3D scene while viewing the picture from different distances along its surface normal. An adaptive staircase procedure was used to determine the aspect ratio of the slanted plane that appeared square. We tested different plane sizes, and also varied the amount of information for viewing distance (binocular viewing and monocular viewing through an aperture). Perceived shape was invariant only for stimulus planes that subtended the smaller visual angles. Judgments were not invariant with larger planes under monocular or binocular viewing. The larger planes appeared to have a higher aspect ratio at greater viewing distances consistent with changes predicted by the retinal image. The failure of invariance with large planes is inconsistent with the pictorial-compensation hypothesis, which states that geometric information in the picture's content is used to recover the depicted scene layout when the picture is viewed from the wrong distance
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