Image processing system for compressing image data including binary image data and continuous tone image data by a sub-band transform method with a high-compression rate
US6459816B2 · kind B2 · utility
37Cited by
4References
2Claims
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Key dates
| Filing date | May 7, 1998 |
| Grant date | Oct 1, 2002 |
| Priority date | — |
| Expiry date | May 7, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T9/005
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An image processing system which compresses an image including both a binary image and a continuous tone image by a sub-band transform method with a high compression rate. A 2×2 pixel matrix block is extracted from image data. A transform factor having a plurality of frequency components is obtained from the 2×2 pixel matrix block data. The transform factor is quantized by a fixed-length quantizing method by deleting a predetermined number of lower order bits of each of the frequency components.
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