Method and apparatus for locating the document referencing corner in a document scanner
US5144455A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 1, 1991 |
| Grant date | Sep 1, 1992 |
| Priority date | — |
| Expiry date | Nov 1, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N2201/04794
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A document to be scanned is corner referenced on a transparent platen, with the document's image facing down. The platen defines an X-Y coordinate system matrix. A moving line of light extends in the X direction and illuminates the document's image, line by line, as the line of light moves in the Y direction. The line of light that is thus reflected from the document is sensed by a linear CCD sensor array having a large number of individual sensor cells arranged in a line that effectively extends in the X direction. Each cell of the CCD array defines an individual pixel (PEL) within the line of light that is reflected from the document. A reflection target is located at a known position relative to the platen's referencing corner, to be scanned prior to scanning the document. Sensing of the target enables (1) the X direction physical position of the CCD sensor array relative to the referencing corner to be accurately determined, and (2) the Y direction physical position of the line of light relative to the the referencing corner to be accurately determined, both parameters being determined prior to scanning of the document.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.