Dot-clock adjustment method and apparatus for a display device, determining correctness of dot-clock frequency from variations in an image characteristic with respect to dot-clock phase
US6924796B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | May 10, 2000 |
| Grant date | Aug 2, 2005 |
| Priority date | — |
| Expiry date | May 10, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G5/008
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The frequency of the dot clock in an image display device is adjusted by calculating a first image characteristic from the differences between adjacent picture elements, varying the phase of the dot clock, determining whether the frequency of the dot clock is correct from the way the first image characteristic varies according to the phase of the dot clock, and changing the frequency if it is incorrect. The first image characteristic is, for example, the maximum difference, the histogram distribution of the differences, or a ratio calculated from the histogram. The phase of the dot clock may be adjusted according to a second image characteristic, such as the difference between a single pair of pixel values, which is also measured over a range of dot-clock phase settings.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.