Patent ID: 7477301

Claim:
A color-noise reduction circuit comprising: pixel substitution means for obtaining a pixel-substitution color-difference signal of a target pixel by substituting an original color-difference signal of the target pixel for a color-difference signal of another pixel residing in an area including the target pixel and by removing high-frequency components from the substituted color-difference signal of the target pixel, and for outputting a noise-reduced color-difference signal of the target pixel by adding the original color-difference signal of the target pixel and the pixel-substitution color-difference signal of the target pixel; differential-signal generating means for obtaining a luminance differential signal and a chroma-saturation differential signal that represent respective differences between a luminance signal and a chroma signal of the target pixel, and a luminance signal and a chroma signal of the another pixel; and pixel-substitution utilization rate calculation means for obtaining a pixel-substitution utilization rate based on the luminance differential signal, the chroma-saturation differential signal and a preliminarily determined threshold value, wherein the pixel substitution means add up the pixel-substitution color-difference signal and the original color-difference signal of the target pixel, based on a pixel-substitution utilization rate obtained by the pixel-substitution utilization rate calculation means.