METHOD AND APPARATUS FOR ADAPTIVELY ENHANCING CONTRAST TO VIDEO SIGNAL BASED ON NON-LINEAR CONVERSION CHANGING WITH TIME, PARTICULARLY REGARDING TO EXECUTING NATURAL ENHANCEMENT CORRESPONDING TO TIME CHANGE CHARACTERISTIC OF VIDEO SEQUENCE

摘要

PURPOSE: A method and an apparatus for adaptively enhancing contrast to a video signal based on non-linear conversion changing with time is provided to execute natural enhancement corresponding to a time change characteristic of video sequence, thereby executing the optimum contrast enhancement for improving output quality. CONSTITUTION: A function block(14) calculates a PDF(Probability Density Function) of input video sequence changing with time. Video parameters related to contrast are extracted from the PDF. A non-linear conversion function is constructed based on the extracted video parameters. The non-linear conversion function is synchronized with the video image or field synchronous signal to be updated to an LUT(Look Up Table). A conversion LUT is applied to an input video signal to enhance an input signal at a block(16).