Systems for reducing noise in video signals using amplitude averaging of undelayed and time delayed signals
US4388729A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 30, 1978 |
| Grant date | Jun 14, 1983 |
| Priority date | — |
| Expiry date | Jun 30, 1998 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/91
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Noise reduction of a signal such as a video signal is effected by averaging a plurality of relatively delayed replica signals, e.g. with line or field delays therebetween, in a decoding processor, the highly redundant information content of the signal being reinforced by the averaging while random noise undergoes a partial cancellation. In order to overcome the problem of signal changes caused by the decoding processor, the signal is encoded prior to application to the noise-introducing signal channel by a complementary encoding processor in which one or more replica signals are subtractively combined with one or more other replica signals. In both processors a variable combining means is employed to exclude from the combination replica signals which have a non-small difference from the replica signals in the combination, thereby to avoid smearing of the information content (with consequent picture smearing in the case of a video signal) when the signal is changing, e.g. because of movement in a picture.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.