A VLSI median filter for impulse noise elimination in composite or component TV signals

A VLSI median filter with novel masking modes and adaptive threshold control is described. The 16 masking modes select 1, 3, 5 or 9 pixels of a 5*3 pixel field for filtering. This feature makes it possible to median-filter NTSC composite video (baseband) or component R, G, and B signals. The input threshold value and the SWAP signal (indicating substitution of the median value) can be used together to adapt transmission path conditions. The circuit removes impulsive noise caused by FM-carrier-to-noise degradation, common in cable and satellite TV systems. The filter is applicable to other impulse noise sources created by auto engines and household appliances, and is also generally useful in image and signal processing tasks.<
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