Patent ID: 7453422

Claim:
A plasma display panel driver comprising: a contour noise estimator responsive to an image signal of a current input frame and an image signal of a previous input frame, for calculating a coding error and a mean gray scale difference and determining a contour noise stage of the image signal of the current input frame for each block based on the coding error and the mean gray scale difference for each block; a gray scale converter responsive to a contour noise estimate for determining whether the image signal of the current input frame is applicable to the contour noise stage determined by the contour noise estimator, determining whether to apply dithering, and using the dithering to convert an input gray scale into a gray scale for reducing the contour noise when applying the dithering; and a subfield converter responsive to a gray scale converter output for generating subfield data corresponding to the gray scale converted by the gray scale converter, wherein the contour noise estimator in a coding error stage uses weights of subfields and results generated by comparing light-emitted patterns of subfields of the image signal of the current input frame and light-emitted patterns of subfields of the image signal of the previous input frame to calculate the coding error, and wherein the contour noise estimator in a gray scale difference stage calculates gray scale differences between the image signal of the current input frame and the image signal of the previous input frame to calculate the mean gray scale difference.