Image enhancing method and circuit using mean separate/quantized mean separate histogram equalization and color compensation

摘要

In an image enhancement method and a circuit therefor, a luminance signal is extracted from input color signals. The luminance signal, extracted in screen units, is divided into subimages according to the mean value of the luminance signal. The gray level histograms of the divided subimages are independently equalized, and an adjusted luminance signal is output. The color signals are varied on the basis of the adjusted luminance signal, and compensated color signals are output. Accordingly, an abrupt variation in brightness and an artifact are effectively reduced, image contrast is enhanced, and an undistorted color signal is provided at the same time. Also, in order to reduce the hardware of the circuit, an input luminance image is quantized, the quantized image is divided into a predetermined number of quantized subimages on the basis of the mean of the quantized image, and an independent histogram equalization is performed on each of the quantized subimages.