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Improved method of finding the illuminant direction of a sphere

[+] Author Affiliations
Richard Dosselmann

University of Regina, Department of Computer Science, 3737 Wascana Parkway, Regina, Saskatchewan, S4S 0A2, Canada

Xue Dong Yang

University of Regina, Department of Computer Science, 3737 Wascana Parkway, Regina, Saskatchewan, S4S 0A2, Canada

J. Electron. Imaging. 22(1), 013035 (Mar 27, 2013). doi:10.1117/1.JEI.22.1.013035
History: Received January 30, 2012; Revised January 18, 2013; Accepted March 6, 2013
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Abstract.  An improved means of finding the direction of a light source illuminating a sphere is presented. In particular, the vertical slant angle of a light source is computed using a new approach. The planar tilt angle of a source is known to be related to the average of the local gradient vectors of an image of a lit sphere. This research uncovers a straightforward link between the length of the average of the local normalized gradient vectors of an image and the slant angle of the corresponding light source. The new technique is far more effective when compared with existing approaches over a variety of test images.

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Topics

Light sources

Citation

Richard Dosselmann and Xue Dong Yang
"Improved method of finding the illuminant direction of a sphere", J. Electron. Imaging. 22(1), 013035 (Mar 27, 2013). ; http://dx.doi.org/10.1117/1.JEI.22.1.013035


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