Television – Image signal processing circuitry specific to television – Noise or undesired signal reduction
Patent
1994-12-20
1996-02-27
Kostak, Victor R.
Television
Image signal processing circuitry specific to television
Noise or undesired signal reduction
348622, 348701, 348404, H04N 521
Patent
active
054952999
ABSTRACT:
A noise reducer for outputting a noise-reduced signal by extracting noise included in an input video signal so as to produce a noise signal and by subtracting the noise signal from the input video signal is provided. The noise reducer includes: a signal processing portion which includes: a delay means for delaying the noise-reduced signal by a predetermined time period thereby outputting a delayed signal; a first subtracter for subtracting the delayed signal from the input video signal thereby outputting a differential signal; an orthogonal transformer for conducting orthogonal transformation on the differential signal, each pixel block of the differential signal being transformed as a unit, thereby outputting an orthogonally transformed signal; a nonlinear processing portion for conducting nonlinear processing on the orthogonally transformed signal based on a predetermined threshold thereby outputting a nonlinear processed signal; an orthogonal inverse transformer for conducting an inverse transformation of the orthogonal transformation on the nonlinear processed signal thereby outputting an inversely transformed signal; an attenuator for attenuating the inversely transformed signal by a predetermined coefficient thereby outputting the noise signal; a second subtracter for subtracting the noise signal from the input video signal thereby outputting the noise-reduced signal; and an adaptive control portion for controlling at least one of the predetermined threshold and the predetermined coefficient based on at least one of the differential signal and the orthogonally transformed signal.
REFERENCES:
patent: 4242705 (1980-12-01), Ebihara
patent: 5043815 (1991-08-01), Yoshimura et al.
patent: 5404179 (1995-04-01), Hamasaki
N. Ebihara et al., "Noise Reducer for Television Signals Using Hadamard Transform", The Journal of the Institute of Television Engineers of Japan, vol. 37, No. 12, pp. 56-62 (1983).
Kobo Kazuo
Kubota Masashi
Suzuki Hidekazu
Kostak Victor R.
Matsushita Electric - Industrial Co., Ltd.
Murrell Jeffrey S.
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