Non-linear contrast control apparatus with pixel distribution measurement for video display system
US5422680A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 24, 1994 |
| Grant date | Jun 6, 1995 |
| Priority date | — |
| Expiry date | Aug 24, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/20
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A video signal to be processed is applied to a non-linear processor having an adjustable gain responsive to a control signal over at least one portion of the amplitude range of the video input signal. A sampling circuit, responsive to the video signal, generates video samples related to the video signal. A control circuit, responsive to the video samples, generates the control signal in accordance with the number of samples in at least a given amplitude range thereby controlling the percentage of samples of a given range in displayed images. Plural control and sampling circuits may be included provide control for white stretch processing, black stretch processing and video mid-point processing for enhancing contrast through out the entire video signal range.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.