Method for image sensor calibration and associated devices
US7502061B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Oct 29, 2004 |
| Grant date | Mar 10, 2009 |
| Priority date | — |
| Expiry date | Nov 6, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N25/772
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An image sensor includes an array of digital pixels, a first frame store for storing reference data, and a second frame store for storing image data. The reference and image data are combine to cancel an off-set of the pixels in the array. A re-set and a calibration phase are performed while a shutter is closed to obtain reference data during a calibration phase. A comparator measures an off-set time to gather information on the off-set of the pixels. During or after an exposure phase a conversion time is measured representative of the illumination on the pixel. During the calibration phase the off-set is measured. This digital technique requires a much smaller voltage swing on the pixel, and known techniques and can be performed in a shorter time. This increases the overall frame rate of the image sensor since the time taken for the reset and calibration phases is less than the time taken for the exposure phase.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.