Image-processing apparatus
US4996602A · kind A · utility
9Cited by
9References
30Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | May 23, 1989 |
| Grant date | Feb 26, 1991 |
| Priority date | — |
| Expiry date | May 23, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/40062
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An input gray-scale image is converted to a bilevel output signal by an image-processing apparatus with two binarizing circuits: one employing a uniform threshold and the other a dither matrix. The outputs of these circuits are selected for each pixel by deciding whether the pixel is a bilevel pixel or a gray-scale pixel. The decision is based on the maximum and minimum gray levels in a block of pixels centered on the pixel in question. Images having both bilevel and gray-scale parts can thus be binarized with clean reproduction of black-white edges.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.