Image reading apparatus for reducing color differences
US6225934A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 24, 1998 |
| Grant date | May 1, 2001 |
| Priority date | — |
| Expiry date | Jul 24, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/56
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
This invention provides an image reading method and apparatus which can prevent a large difference from being produced between the color tones of the read image and the original image. A plurality of signals output from an image sensor (101) are A/D-converted into a plurality of digital signals by A/D conversion circuits (105), a predetermined one of the A/D-converted digital signals is compared with a predetermined reference level by a comparator (108), a low-pass filter (109) removes any high-frequency component from the comparison result, and the output from the low-pass filter (109) is controlled to be input to the A/D conversion circuits (105) as a reference voltage for determining the input range of each A/D conversion circuit (105).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.