CMOS imager having asynchronous pixel readout in order of pixel illumination
US6660989B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 8, 2002 |
| Grant date | Dec 9, 2003 |
| Priority date | — |
| Expiry date | Jul 17, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N25/772
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
This CMOS imager represents illuminance in the time domain. Once per frame, each pixel outputs a pulse after a time proportional to the illuminance on that pixel. Therefore, the illuminance on that pixel is related to the time difference between its pulse event and global reset of the imager. A counter reports the times of these pulse events in a digital format. Thus no analog to digital converter is necessary. This imager enables easy computation of pixel intensity histograms. Frame data is stored in pixel intensity order using row and column arbiters to produce a pixel address. Because each pixel has its own exposure time, the imager has a wide dynamic range of 120 dB. This imager has low power dissipation and avoids the noise and mismatch problems of prior complicated analog readout circuits.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.