Noise reduction apparatus for video signal
AssigneeKabushiki Kaisha Toshiba
InventorTsutomu Mizusawa
Life of this patent
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Abstract
A noise reduction apparatus includes a frame type noise processing circuit which detects a correlation between two successive frames of a video signal and reduces noncorrelating parts of the video signal. A processed signal from the frame type circuit is mixed with a delayed video signal at a rate determined according to a degree of motion of an image represented by the video signal. A line type noise processing circuit detects a correlation between two successive lines of a mixed video signal and reduces noncorrelating parts of the mixed video signal. The line type circuit is controlled so as to change a characteristic of noise processing according to the degree of motion.
Claims15
Apparatus for reducing noise mixed in a video signal, the apparatus comprising:
- delay means, coupled to receive the video signal, for providing a delayed video signal;
- first noise processing means, coupled to receive the video signal, for detecting a correlation between two successive frames or two successive fields of the video signal, for reducing noncorrelating parts of the video signal caused by noise, and for providing a processed signal;
- motion detection means, coupled to receive the video signal, for detecting a degree of motion of an image represented by the video signal;
- mixing means for mixing the delayed signal and the processed signal at a first rate when the detected degree of motion is greater than a first predetermined level, and at a second rate when the detected degree of motion is less than a second predetermined level, and for providing a mixed video signal;
- second noise processing means for detecting a correlation between two areas in a field of the mixed video signal, for reducing noncorrelating parts of the mixed video signal, and for providing an output video signal;
- and
- control means for limiting an effect of the second noise processing means when the detected degree of motion is less than a third predetermined level.
An apparatus for reducing noise in a video signal, said apparatus comprising:
- a delay circuit which receives the video signal and outputs a delayed video signal;
- a first noise processing circuit, which receives the video signal, for detecting a correlation between two portions of the video signal, for reducing non-correlated portions of the video signal caused by noise and for generating a processed video signal;
- a motion detector, which receives the video signal, for detecting a degree of motion between the two portions of the video signal and for generating a motion detection signal indicating the degree of motion;
- a mixing circuit for mixing the processed video signal and the delayed signal according to the motion detection signal and producing a mixed video signal;
- and
- a second noise processing circuit for detecting a degree of correlation between two areas in a field of the mixed video signal, for reducing non-correlated portions of the mixed video signal based on the motion detection signal, and for generating an output video signal.
Dependencies are inferred from the claim text.