APPARATUS AND A METHOD FOR CONTROLLING A BLACK/WHITE STRETCH ACCORDING TO A CHANGE OF A SCENE, PARTICULARLY CONCERNED WITH IMPROVING THE CONTRAST OF A SCREEN

摘要

PURPOSE: An apparatus and a method for controlling black/white stretch according to change of a scene are provided to improve the contrast of a screen by adjusting a slope variation speed of a mapping function according to the change of the scene. CONSTITUTION: A scene change detection part(110) compares a previous frame and a current frame to determine whether a scene has been changed or not. A minimum/maximum signal detection part(120) detects a signal having a minimum level and a signal having a maximum level from input signals. A slope/tilt calculation part(130) determines a tilt value for deciding a stretch area of an input signal area, and calculates a mapping slope of the stretch area by each frame. A slope determination part(140) determines a mapping slope of an output signal according to the change of the scene. A mapping part(150) applies an input signal to a mapping function having the mapping slope of the output signal, and then perform a mapping operation.