CONTOUR EMPHASIZING CIRCUIT

摘要

A contour emphasizing circuit which comprises a contour pick-up unit 10 for picking up a contour component HE from an input luminance signal Y, a level judging unit 15 for judging the luminance level of the input luminance signal Y, a coefficient control unit 17 for changing the coefficient in a plurality of steps depending upon a judgement signal and multiplying the contour component HE by the coefficient to output the product, and an adder 14 for adding the contour component outputted from the coefficient control unit 17 to the input luminance signal Y to output an emphasized-contour luminance signal. The coefficient to be multiplied by the contour component HE is changed in a plurality of steps depending upon the luminance level of the input luminance signal Y, and the contour component HE to be added to the input luminance signal Y is controlled to have a magnitude appropriate to the luminance level of the input luminance signal Y. As a result the contour is emphasized according to the luminance level of the input luminance signal Y without causing excessive contour emphasis by adding a large contour component to a dark image of a small luminance level, thus preventing formation of unnatural images.