Adaptive histogram-based video contrast enhancement
US8295596B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 7, 2005 |
| Grant date | Oct 23, 2012 |
| Priority date | — |
| Expiry date | Apr 27, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2207/20172
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The adaptive contrast enhancer uses an adaptive histogram equalization-based approach to improve contrast in a video signal. For each video frame, the histogram of the pixel luminance values is calculated. The calculated histogram is divided into three regions that are equalized independently of the other. The equalized values are averaged with the original pixel values with a weighting factor that depends on the shape of the histogram. The weighting factors can be also chosen differently for the three regions to enhance the darker regions more than the brighter ones. The statistics calculated from one frame are used to enhance the next frame such that frame buffers are not required. Many of the calculations are done in the inactive time between two frames.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.