Encoding system capable of accomplishing a high efficiency by anterior and/or posterior processing to quantization
US4908862A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Nov 10, 1987 |
| Grant date | Mar 13, 1990 |
| Priority date | — |
| Expiry date | Nov 10, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/91
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In an encoding system responsive to a sequence of coefficient signals which results from a predetermined linear transform and which is divided into a sequence of blocks, anterior processing is carried out prior to quantization about the coefficient signals in each block to determine a significant area of the coefficient signals by comparing each level of the coefficient signals with a threshold level. Only the coefficient signals within the significant area are judged to be valid and produced as a sequence of significant coefficient signals from a classifying circuit (20) to be quantized by a quantizer (15) into a sequence of quantized signals. The quantized signal sequence is subjected to posterior processing to produce a sequence of encoded signals. The significant area may be decided by the use of a selected one of zone detection, zigzag scanning, and adaptive scanning. In the posterior processing, the quantized signals may be encoded into the encoded signals by the use of a plurality of code sets or tables.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.