APPARATUS AND METHOD FOR CONTRAST ENHANCEMENT USING DOMINANT BRIGHTNESS LEVEL AND ADAPTIVE INTENSITY TRANSFORMATION

摘要

PURPOSE: A contrast improvement apparatus and a method by the conversion of a major brightness level and an adaptive brightness value are provided to divide a sub band of a low frequency component with the brightness information of an image according to a brightness level and to improve the contrast of the divided sub band individually, thereby improving the contrast of an image and preventing the distortion of the detailed information in a bright area and a dark area. CONSTITUTION: A wavelet transformation unit(110) disassembles an input image into a plurality of sub bands through a discrete wavelet transformation for the input image. A brightness level calculator(120) calculates the major brightness level for each coordinate of the sub band of the low frequency component among the plurality of sub bands. An image division unit(130) divides the sub band of the low frequency component into a plurality of layers. A contrast improvement unit(140) converts the brightness value of each layer. An image synthesis unit(150) synthesizes the layers to improve the contrast. [Reference numerals] (110) Wavelet transformation unit; (120) Brightness level calculator; (130) Image division unit; (140) Contrast improvement unit; (150) Image synthesis unit