Noise reduction circuit for video signal
US4709269A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 17, 1987 |
| Grant date | Nov 24, 1987 |
| Priority date | — |
| Expiry date | Feb 17, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/21
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A noise reduction circuit for video signal comprises first through third circuits each for obtaining from an input video signal a high frequency component including a noise component and for limiting large amplitude parts thereof, where a filter part of the second circuit has an impulse response characteristic wherein an amplitude increases or decays with time and is complementary to that of a filter part of the first circuit and a filter part of the third circuit has an impulse response characteristic which is essentially a combination of the two impulse response characteristics, and a fourth circuit for carrying out a subtraction between the input video signal and an output signal of the first circuit so as to obtain a first signal which is substantially eliminated of the noise component except for a noise component and distortion remaining at parts in vicinities of rises and falls in the video signal caused by the amplitude limitation carried out in the first circuit, carrying out a subtraction between output signals of the second and third circuits so as to obtain a second signal which includes the noise component and the waveform distortion of the first signal with an inverted…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.