Projects per year
Abstract
People readily perceive smooth luminance variations as being due to the shading produced by undulations of a 3-D surface (shape-from-shading). In doing so, the visual system must simultaneously estimate the shape of the surface and the nature of the illumination. Remarkably, shape-from-shading operates even when both these properties are unknown and neither can be estimated directly from the image. In such circumstances humans are thought to adopt a default illumination model. A widely held view is that the default illuminant is a point source located above the observer's head. However, some have argued instead that the default illuminant is a diffuse source. We now present evidence that humans may adopt a flexible illumination model that includes both diffuse and point source elements. Our model estimates a direction for the point source and then weights the contribution of this source according to a bias function. For most people the preferred illuminant direction is overhead with a strong diffuse component.
Original language | English |
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Pages (from-to) | 2317-2330 |
Number of pages | 14 |
Journal | Vision Research |
Volume | 51 |
Issue number | 21-22 |
Early online date | 16 Sept 2011 |
DOIs | |
Publication status | Published - Nov 2011 |
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Dive into the research topics of 'Sun and sky: Does human vision assume a mixture of point and diffuse illumination when interpreting shape-from-shading?'. Together they form a unique fingerprint.Projects
- 2 Finished
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Estimating the intrinsic characteristics of real images to aid analysis
Schofield, A. & Spann, M.
Engineering & Physical Science Research Council
1/04/08 → 6/10/11
Project: Research Councils
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Mechanisms of Shading and Texture Analysis in the Perception of 3-D Surfaces
Schofield, A.
Engineering & Physical Science Research Council
1/04/03 → 30/09/06
Project: Research Councils