White noise cancellation method and white noise cancellation circuit for performing the same

摘要

Disclosed are a white noise removing method included in a video image input signal, and a white noise removing circuit for performing the same. After the input video image signal passes through the video processor to filter and contour correct the low pass component, the video signal of the low pass component edge-compensated is subtracted from the signal passed through the video processor. In addition, the video image signal is input to the sync separator to separate the video sync signal, and the noise level detector detects the noise level applied to the video sync signal, regards it as the total noise level, and adjusts the limiter level α using this level. , And add and subtract α values with the first summer and the third summer. At this time, if the noise level of the detected sync signal is large, the width α value of the limiter becomes large. After limiting the subtracted signal, subtract the limiting signal from the subtracted signal, separate the sign (±) signals through a signal separator, add and subtract each of them, and synthesize them, and then contour-correct the pre-synthesized signal. Synthesizing the low pass component video signal removes white noise and outputs a contour corrected low pass video signal. Accordingly, by eliminating the white noise displayed on the screen, the white noise that can be felt during viewing is prevented, thereby forming an improved white noise removing circuit.