Method and apparatus for automatic gain and exposure control for maintaining target image brightness in video imager systems
US7245320B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 4, 2002 |
| Grant date | Jul 17, 2007 |
| Priority date | — |
| Expiry date | Jul 18, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N23/76
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In an image processing system, the imager gain and the exposure time are adjusted based on a predefined stepping sequence using a stepping table designed to maximize the signal-to-noise ratio in the image. This is achieved by providing a stepping sequence with each step having the largest suitable integration time (exposure) and an appropriate amplifier and digital gain setting, while achieving an equal relative percentage change in image brightness between adjacent sequence steps. The size of the executed AE steps is proportional to the distance between a current image luminance and the target luminance. This is achieved by the capability to skip one or more steps in the stepping sequence, if appropriate, for each relevant executed step, with the number of skipped steps, if any, being proportional to the magnitude of the deviation from the target brightness.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.