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Measuring Sensitivity to Viewpoint Change with and without Stereoscopic Cues
Published on: December 4, 2013
Vertical disparity affects shape and size judgments across surfaces separated in depth
Lisa M O'Kane1, Paul B Hibbard
1School of Psychology, University of Glasgow, 58 Hillhead Street, Glasgow G12 8QB, Scotland, UK.
Perception
|July 13, 2007
Summary
Vertical disparity, crucial for 3-D shape perception, influences perceived size and shape even for small objects. This visual cue
Area of Science:
- Visual perception
- Computational neuroscience
- 3-D geometry
Background:
- Vertical binocular disparity is a cue for 3-D shape recovery.
- Its role in metric shape judgments is limited by the required field of view for small retinal images.
- Pooling vertical disparity over large areas may overcome this limitation.
Purpose of the Study:
- To investigate if vertical disparity information from a large surround surface influences the perceived size and 3-D shape of a small central object.
- To determine if vertical disparity affects metric depth perception for objects with small retinal images.
Main Methods:
- Observers adjusted a virtual ellipsoid's size and shape to match a real tennis ball.
- The virtual ball was presented at varying distances (200-450 mm).
- Vertical disparities of a large surround surface were manipulated (160 mm or infinity).
Main Results:
- Perceived size and 3-D shape of the central object were significantly influenced by the surround's vertical disparity.
- This effect was independent of whether the surround and target were at the same distance.
- Vertical disparity influenced perceived distance to surfaces.
Conclusions:
- Vertical disparity is important for metric depth perception, even for objects with small retinal images.
- The perceived distance to a surface is influenced by the vertical disparity of surrounding surfaces.
- Visual system integrates vertical disparity information across large spatial extents.
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