Image reading apparatus
US5105286A · kind A · utility
Inventor
Key dates
| Filing date | Mar 12, 1990 |
| Grant date | Apr 14, 1992 |
| Priority date | — |
| Expiry date | Mar 12, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/4076
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An image reading apparatus includes a plural number of line image sensors disposed on a read line, a background detection circuit for detecting a background level of an original document on the basis of an image signal from a sample portion of a reference line image sensor as a line image sensor facing the original document. The sample portion is predetermined as a portion facing the original document. The apparatus also includes a conversion circuit for converting image signals output from the line image sensors, into image data expressed as a relative level when the background level detected by the background detection circuit is used as a white reference level.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.