Automatic contour correction method and automatic contour correction circuit suitable for performing the same

摘要

An automatic contour correction method and an automatic contour correction circuit suitable for performing the same are disclosed. The first switch switches the luminance signal and the synchronization signal to generate the first switching signal, the delay unit generates the first delay signal and the second delay signal, and the peak detector receives the primary delay signal and the secondary delay signal to control gain. The peak detection signal is output based on the voltage. A summer adds the first delay signal and the peak detection signal to output a peaking luminance signal, the second switch switches the peaking luminance signal, and the high pass filter filters the high-pass portion of the peaking luminance signal selected by the second switch. . The peak rectifier detects the peak value of the high pass signal, and the high gain amplifier receives the user-controlled sharpness control signal and peak value, subtracts and amplifies it, and the gain control voltage generator samples and holds the amplified signal for gain control. A voltage is generated and provided to the peak detector. As a result, a gain control voltage for determining the peaking amount is determined by using a synchronous signal pulse as a reference signal in the retrace period during which no luminance signal exists, and the peaking amount is fixed based on the determined gain control voltage for the luminance signal. By doing so, the sharpness of the screen can be controlled regardless of the fluctuation of the screen. In addition, it is possible to reduce noise components generated by emphasizing the components of the high range in the video signal.