Adaptive unsymmetrical dither region to improve dynamic false contour in PDPs

Because dynamic false contour (DFC) can be improved by selecting a limited number of gray scales in plasma display panels (PDPs), the other gray scales unselected are realized by dither. In order to reduce the noises caused by dither, a method using adaptive unsymmetrical dither region in which DFC may occur is proposed. The evaluated method with vision characteristic for DFC is obtained firstly after analyzing the luminance distribution of DFC stripe. Then the dither widths of bright and dark DFC stripe regions to realize gray scales are computed and changed according to the degree of the vision sensitivity to DFC. The experiment results show that the width of dither region can change and keep the minimum adaptively according to the degree of vision sensitivity to DFC. The gray scales are expressed smoothly, simultaneously. The peak signal noise ratio (PSNR) of image displayed in this method is better than other methods.