20-08-2013, 04:34 PM
A Histogram Modification Framework and Its Application for Image Contrast Enhancement
ABSTRACT
A general framework based on histogram equalization for image contrast en-
hancement is presented. In this framework, contrast enhancement is posed as an
optimization problem that minimizes a cost function. Histogram equalization is an
effective technique for contrast enhancement. However, a conventional histogram
equalization (HE) usually results in excessive contrast enhancement, which in turn
gives the processed image an unnatural look and creates visual artifacts. By in-
troducing specifically designed penalty terms, the level of contrast enhancement
can be adjusted; noise robustness, white/black stretching and mean-brightness
preservation may easily be incorporated into the optimization. Analytic solutions
for some of the important criteria are presented. Finally, a low-complexity algo-
rithm for contrast enhancement is presented, and its performance is demonstrated
against a recently proposed method.