Image coding system coding digital image signals by forming a histogram of a coefficient signal sequence to estimate an amount of information
US4920426A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Nov 9, 1987 |
| Grant date | Apr 24, 1990 |
| Priority date | — |
| Expiry date | Nov 9, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/91
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In an image coding system having a plurality of coding characteristics, such as quantization characteristics, information of a digital image signal sequence is monitored in each of a number of predetermined intervals by forming a histogram of a sequence of coefficients which is calculated from the digital image signal sequence in accordance with each of the coding characteristics. The amount of information is calculated by summing up the coefficients in relation to every one of the coding characteristics. An optimum one of the coding characteristics is indicated by the coding control circuit to code the coefficient sequence into a sequence of coded signals in accordance with the optimum coding characteristic. The coefficient sequence in each frame may be divided into a sequence of blocks each of which is judged to be either valid or invalid in relation to each coding characteristic. Results of judgement may be included in the amount of information.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.