Data processor
US5841551A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 25, 1996 |
| Grant date | Nov 24, 1998 |
| Priority date | — |
| Expiry date | Jan 25, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/30
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a data processor, in order to discriminate the kind of image in a processing block quickly and correctly, image data is divided into first processing blocks of m*m pixel matrices and second processing blocks of M*M pixel matrices wherein M>m. The second processing block includes the data of the first processing block and adjacent pixels around it. Image data in the first and second processing blocks are subjected to orthogonal transform to generate coefficient data. The image type is discriminated as a character image, a dot image or a half-tone image according to the coefficient data of the second processing block and an appropriate quantization table is then selected. Having identified the appropriate quantization table based on analysis of second processing block, image data of the first processing block is quantized according to the thus selected quantization table and quantized data is thereby coded.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.