Device for determining focused state of taking lens
US6833538B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Dec 4, 2003 |
| Grant date | Dec 21, 2004 |
| Priority date | — |
| Expiry date | Dec 4, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N23/959
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a focusing state determining device for determining a focusing state of a taking lens, an object light entering the taking lens is captured by focusing state determination imaging elements provided separately from a video imaging element, and the focusing state is determined according to luminance signals outputted from the focusing state determination imaging elements. Any error of determination of the focusing state induced by saturation of the luminance signals in imaging an object of high luminance is prevented by adjusting the gains of the image signals outputted from the focusing state determination imaging elements or the charge accumulation times of the focusing state determination imaging elements. High-frequency components are determined from the luminance signals obtained from the focusing state determination imaging elements (A, B, C), and the focus evaluation value is determined by integration thereof. An automatic gain control circuit (82) adjusts the gains of the luminance signals so that the maximum levels of the luminance signals may not reach the saturation levels.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.