Method and apparatus for detecting optimum lens focus position
US7280149B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 2001 |
| Grant date | Oct 9, 2007 |
| Priority date | — |
| Expiry date | Jul 19, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N2101/00
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention is a technique for measuring optimum focus position of a lens to include the steps of capturing a digital image in the field of view, digitally compressing the image to provide a compressed file having a file size and providing a focus accuracy parameter derived from the file size of the compressed file. The key point of this invention is the recognition that the compressed file associated with a given image increases monotonically in size as the image is brought into focus. The latter occurs because a focused image has greater information content than an unfocused image. With such a technique, an optimal focus position of a lens can be determined by maximizing a single parameter, the compressed output file size.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.