Method of optimal focusing for document scanner
US7215447B2 · kind B2 · utility
Inventor
Key dates
| Filing date | Sep 10, 2002 |
| Grant date | May 8, 2007 |
| Priority date | — |
| Expiry date | Aug 16, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N2201/0434
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method of optimal focusing for a document scanner is disclosed. The scanner includes an optical module movable in a given scanning direction to perform scanning operation over an area of a document in a scan line by scan line manner by being driven by an optical module moving mechanism under control of a control unit. The control unit includes a best focus value memory for storage of the best focus value for each scan line. The method includes the steps of moving the optical module to one of the scan lines of the document and retrieving the best focus value corresponding to the selected scan line. A focus adjusting mechanism is controlled by the control unit to move the optical module in a second direction to adjust the focus position of the optical module in accordance with the best focus value of the scan line. Once the optical module reaches the scan line, the operation of the optical module is temporarily suspended in order to have the vibration of the optical module damped out. Thereafter, a scanning operation is performed over the scan line.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.