PURPOSE: To reduce the noise like distortion by using a noise reduction means consisting of a limiter circuit which allows a short-amplitude value to pass through and a filter circuit which extracts data having a space frequency compo nent in a high band by delay and addition/subtraction.
CONSTITUTION: A noise reduction circuit 18 is provided after discrete cosine inverse conversion. Picture element data is inputted to the circuit 18 from a terminal 21, and one data is sent to a delay circuit 22, and the other is sent to a noise extraction path consisting of an HPF 25 and a nonlinear limiter 26. The limiter 26 limits the amplitude of a high-band signal Y passing the HPF 25 and has such nonlinear characteristic that only the short-amplitude component is allowed to pass as a noise Z. The extracted noise is eliminated from the original picture signal, which passes a delay circuit 22 to cancel the delay of the processing time, by an adding circuit 23. Since the distortion is corrected by noise reduction after restoration to picture element data, the visual effect is increased.
OKU MASUO
TAKAHASHI SUSUMU
ICHIGE KENJI
| JP63079938B | ||||
| JP61194530B | ||||
| JP61133039B | ||||
| JPS6365439B2 | 1988-12-15 | |||
| JPH0230345B2 | 1990-07-05 | |||
| JP56056335B |
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