Image compression/decoding apparatus and method
US6873739B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 14, 2001 |
| Grant date | Mar 29, 2005 |
| Priority date | — |
| Expiry date | Mar 4, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T9/007
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An image compression apparatus is provided, which includes a wavelet transformer, a quantizer, a comparator, a subtracter, a low data compressor and a high data compressor. The comparator compares the first quantization coefficients of the first quantization data, to output the maximum quantization coefficient. The subtracter subtracts the minimum quantization coefficient from the maximum quantization coefficient, to output a subtraction constant. The low data compressor subtracts the subtraction constant from the first quantization coefficients, to output low compression data obtained by compressing the first quantization data. The high data compressor sequentially generates first compression data obtained by coding the number of zero quantization coefficients each having at least one successive zero value among the second quantization coefficients, and second compression data obtained by coding the second quantization coefficients other than the zero quantization coefficients according to a coding rule, to output high compression data.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.