Image reading apparatus and method
US4914524A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 20, 1988 |
| Grant date | Apr 3, 1990 |
| Priority date | — |
| Expiry date | Jul 20, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/4051
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An image reading apparatus for converting an image on a document having a white/black text area into a display signal. An image reader scans pixels forming the image to produce a read signal having a level corresponding to the brightness density of each of the scanned pixels. The read image is compared with a dither matrix data signal and converted into a dither converted signal. The read image is also compared with a threshold value and converted into a binary signal having a first level representing a white pixel and a second level representing a black pixel. A discrimination circuit receives the binary signal for producing a detection signal when the white/black text area is scanned. Upon occurrence of the detection signal, the dither converted signal is mixed with the binary signal to form the display signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.