The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 24, 2012
Filed:
Sep. 22, 2008
Wai Pak Choi, Hong Kong, HK;
Stephen Wai-yan Lai, Hong Kong, HK;
Wing Chi Stephen Chan, Hong Kong, HK;
Wai Pak Choi, Hong Kong, HK;
Stephen Wai-Yan Lai, Hong Kong, HK;
Wing Chi Stephen Chan, Hong Kong, HK;
Solomon Systech Limited, New Territories, HK;
Abstract
Methods and apparatuses of contrast enhancement on an image are disclosed. The method performs local shading of fine contrast variations in an image, with particular advantage in tone mapping applications. The amounts of shading are determined by the preferred degree of increased image contrast, including compensation for subsequent tone mapping, and the difference between a profile signaland the image signalconditional on the signal profile level being higher than the original image signal level, wherein avoiding boosting of brightness level to obtain contrast enhancement. The profile signalis calculated by the weighted sum of the image signal and the absolute signal variation which is the absolute value of the variation between the brightness of two neighbor pixels. This amount of shading is reduced to zero when the profile signalis lower than the original image signalfor avoiding the overshooting problem at sharp edges in an image. Uniform RGB scaling is applied to preserve original color tones.