Image processing apparatus
US4709274A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 27, 1984 |
| Grant date | Nov 24, 1987 |
| Priority date | — |
| Expiry date | Aug 27, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/4055
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An image processing apparatus has a slice binarizing circuit, a dither process circuit, maximum and minimum density measuring circuits, a comparator for determining if each image area is a binary or halftone image area, and a RAM for storing an output from the comparator. An average value of the difference between the maximum and minimum densities can be calculated, and outputs from the slice binarizing circuit and the dither process circuit can be ANDed or ORed in accordance with a comparison result of the average value with a reference value. An image density gradient or image tone data in an image block can also be calculated to allow multi-level quantization and optimal image reproduction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.