Autofocus process and system with fast multi-region sampling
US6201619A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 18, 1998 |
| Grant date | Mar 13, 2001 |
| Priority date | — |
| Expiry date | Jun 18, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/193
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An autofocus process for imaging optics of a scanner comprises performing multiple scan-line image captures of the document to be scanned. In the preferred embodiment, these captures are of essentially the same scan-line. A focal position of imaging optics, which forms a scan-line image, is adjusted relative to an image detector in between the multiple scan-line captures of image data. In the preferred embodiment, the imaging optics is adjusted. Relay optics or a position of the image detector could alternatively be adjusted. In any case, a focus setting for a subsequent scanning operation is then calculated based on the image data from the multiple scan-line captures. In the preferred embodiment, this calculation yields a lens position for the imaging optics. The invention thus allows autofocussing to the document to be scanned. Problems associated with loss of calibration are avoided. Moreover, the system is able to adapt to documents where the image is not at the scanner's nominal focal plane.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.