Weighted gradient based and color corrected interpolation
US7256828B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 21, 2003 |
| Grant date | Aug 14, 2007 |
| Priority date | — |
| Expiry date | Feb 5, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N25/134
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The apparatus and method invented are operating upon a digital image signal obtained from an image sensor. The sensor is covered with different colored filters and is only able to record the color transmitted through each specific filter into the photosite or pixel. This type of sensor is known as a color filter array or CFA sensor. The different colored filters are arranged in a predefined pattern across the sensor. To obtain a full color image the missing color information is estimated by a set of weighed values obtained by an inverted gradient function. The set of weighted values is found from the neighboring pixels in the four compass directions, north, east, west and south or is found horizontally and vertically. The surrounding pixels are corrected by the chrominance channel to better fit the center pixel in the luminance channel, prior to using the gradient functions. The chrominance channel is interpolated in a similar manner and is also corrected to better fit the center pixel before the inverted gradient functions are applied.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.