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Proceedings Paper

Depth map from focus for cell-phone cameras
Author(s): R. Safaee-Rad; M. Aleksic
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Paper Abstract

Cell-phone cameras generally use mini lenses that are wide-angle and fixed-focal length (4-6 mm) with a fixed aperture (usually f/2.8). As a result, these mini lenses have very short hyper-focal lengths (e.g., the estimated hyper-focal length for a 3.1-MP cell-phone camera module with a 5.6-mm mini lens is only about 109 cm which covers focused-object distances from about 55 cm to infinity). This combination of optical characteristics can be used effectively to achieve: (a) a faster process for auto-focusing based on a small number of pre-defined non-uniform lens-position intervals; and (b) a depth map generation (coarse or fine depending on the number of focus regions of interest--ROIs) which can be used for different image capture/processing operations such as flash/no-flash decision-making. The above two processes were implemented, tested and validated under different lighting conditions and scene contents.

Paper Details

Date Published: 3 March 2008
PDF: 8 pages
Proc. SPIE 6817, Digital Photography IV, 68170Z (3 March 2008);
Show Author Affiliations
R. Safaee-Rad, AMD (Canada)
M. Aleksic, AMD (Canada)

Published in SPIE Proceedings Vol. 6817:
Digital Photography IV
Jeffrey M. DiCarlo; Brian G. Rodricks, Editor(s)

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