Edge enhancement with background noise reduction in video image processing
US6404460B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 19, 1999 |
| Grant date | Jun 11, 2002 |
| Priority date | — |
| Expiry date | Feb 19, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/21
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention is directed to a method and apparatus for image edge enhancement with background noise reduction. According to the method and apparatus, background noise is reduced through use of feed forward gain control and threshold control of a sharpness control amplifier. In a prior art circuit, the sharpness control amplifier was controlled only by a sharpness control signal. By controlling the sharpness control amplifier also with a feed forward gain control and a threshold control, the circuit can be made to have background noise reduction while maintaining a continuous input/output characteristic curve. According to the input/output characteristic curve, when the amplitude of the transitions of the video signal are below a particular threshold value, the amplification of the sharpness control amplifier is reduced by the gain control, such that low amplitude noise signals are reduced. When the amplitude of the transitions of the video signal, representing image edge transitions, are above the amplitude of the threshold level, then normal signal amplification is produced. In this manner, the edges of the image are enhanced while background noise is reduced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.