| 摘要 |
In a gradation corrector used in a television receiver, a clipping circuit (51) is connected to an output of a histogram memory (2) and a clipping level of the clipping circuit (51) is changed in accordance with an output of an S/N detecting circuit (50). Thereby, when the minimum value is detected, it is possible to prevent a large variation of the value to be detected which may be caused from noise or the like. Also, a circuit (52) for detecting a change in video scene and a recursive filter circuit composed of an adder (53) and a xK circuit (54) (and a two-input/one-output selector circuit (55)) are provided on the output side of a clipping circuit (51) and the coefficient value K of the xK circuit (54) (or the selector circuit (55) is controlled in accordance with an output of the video scene change detecting circuit (52). Thereby, it is possible to make a smooth gradation correction which is not affected by noises or the like (or to make a gradation correction with rapid response which follows a change in video scene). <IMAGE> |
