Noise reduction apparatus for television receiver

摘要

A noise reduction apparatus for use in a television receiver or VCR using the NTSC format, in which a video signal or a demodulated color difference signal is processed by an operational circuit which supplies a noise-reduced output signal to a first one of two series-connected one-frame delay elements and which compares the input video signal with an output signal from the first 1-frame delay element, to execute noise reduction. A degree of noise reduction executed by the operational circuit is controlled in accordance with the degree of correlation between the output signal from the second 1-frame delay element and the input video signal, such that the degree of noise reduction is made small or zero when the correlation is below a predetermined level, indicating the presence of motion components in the video signal. Due to the 2-frame delay used in judging that degree of correlation, the judgement will not be adversely affected by interference components of the video signal which result from interaction between the chroma and high-frequency luminance components of the video signal, when there are no motion components in that signal.