Method and apparatus for coding image information, and method of creating code books
US5341441A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 11, 1993 |
| Grant date | Aug 23, 1994 |
| Priority date | — |
| Expiry date | Jan 11, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/60
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A coding apparatus divides digital image information into pixel blocks each having a size of m.times.n pixels, and subjects the image information to vector quantization in block units. The pixel blocks are orthogonally transformed and the characteristics and sequency components of the pixel blocks are detected. Each pixel block is divided into a plurality of sub-blocks in conformity with the detected sequency components. Respective ones of the plurality of divided and outputted sub-blocks are scalar-quantized into sub-vectors of a predetermined number of bits in conformity with the characteristics of the pixel blocks. Respective ones of the scalar-quantized values of the quantized sub-blocks are vector-quantized in conformity with the characteristics of the pixel blocks, these vector-quantized reproduction vector codes are combined and the result is subjected to further vector quantization.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.