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Proceedings Paper

New approach to auto-white-balancing and auto-exposure for digital still cameras
Author(s): Nasser Kehtarnavaz; Hyuk-Joon Oh; I. Shidate; Youngjun F. Yoo; R. Taluri
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Paper Abstract

This paper presents an auto-white balancing algorithm named scoring. The spectral distributions of the Macbeth reference colors together with the spectral distributions of various color temperature light sources are used to obtain a number of reference color points in the CbCr color space. A number of representative color points are also obtained from a captured image by using a previously developed multi-scale clustering algorithm. A match is then established between the set of reference colors and the set of representative colors. The matching scheme generates the most likely light source candidate under which the image is taken. Furthermore, this paper presents an auto-exposure algorithm using a mapping from the luminance histograms of five sub- areas in the image to an exposure value. A neural network is designed to perform the mapping. The histogram in each sub- area is used to determine the mean, variance, minimum, and maximum luminance for that sub-area. The same spatial information is computed for previous frames to incorporate temporal changes in luminance into the network.

Paper Details

Date Published: 24 April 2002
PDF: 9 pages
Proc. SPIE 4669, Sensors and Camera Systems for Scientific, Industrial, and Digital Photography Applications III, (24 April 2002); doi: 10.1117/12.463431
Show Author Affiliations
Nasser Kehtarnavaz, Texas A&M Univ. and Texas Instruments Inc. (United States)
Hyuk-Joon Oh, Texas A&M Univ. and Texas Instruments Inc. (United States)
I. Shidate, Texas Instruments Inc. (United States)
Youngjun F. Yoo, Texas Instruments Inc. (United States)
R. Taluri, Texas Instruments Inc. (United States)


Published in SPIE Proceedings Vol. 4669:
Sensors and Camera Systems for Scientific, Industrial, and Digital Photography Applications III
Nitin Sampat; John Canosa; Morley M. Blouke; John Canosa; Nitin Sampat, Editor(s)

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