Encoder capable of faithfully and adaptively encoding a moving image
US4734767A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Mar 24, 1987 |
| Grant date | Mar 29, 1988 |
| Priority date | — |
| Expiry date | Mar 24, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/91
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In an encoder responsive to a sequence of coefficient blocks each of which is composed of a plurality of orthogonal transform coefficients subjected to predictive encoding and orthogonal transform, the coefficient blocks are classified by a classification circuit (55) into a plurality of classes to produce a control signal (CONT) representative of the classes. A quantization unit (60), a code conversion unit (61), and a coefficient selection unit (62, 64) are controlled by the control signal to select quantization characteristics, code conversion characteristics, and coefficient selection characteristics. The quantization unit comprises a plurality of quantizers corresponding to the quantization characteristics while the code conversion unit and the coefficient selection unit comprise a plurality of code converters and a plurality of selection tables corresponding to the code conversion characteristics and the coefficient selection characteristics, respectively. Consequently, the coefficients are adaptively encoded into a reduced amount of encoded codes on encoding a moving image.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.