Picture coding device where the quantization step is adjusted in response to a motion vector
US6011589A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Feb 24, 1997 |
| Grant date | Jan 4, 2000 |
| Priority date | — |
| Expiry date | Feb 24, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/15
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An object of the present invention is to improve visual picture quality. A picture signal is divided into a plurality of macro blocks and coding is conducted in macro block units. The coding is conducted including quantization process by a quantization portion. A motion compensation portion outputs the quantity of motion, L, in macro block units. An average quantity of motion, L.sub.ave, of a reference picture stored in a frame memory is outputted from a division portion. A control portion compares the quantity of motion L with two reference values relative to the average quantity of motion L.sub.ave and makes a correction to lower the quantization step in the quantization portion for macro blocks whose quantity of motion L is between the reference values. Accordingly, picture quality is improved in part of picture where motion is small and deterioration of visual picture quality is noticeable. At the same time, since the correction is not applied to picture with such slow motion that deterioration of picture quality is small, redundancy of coded signal does not unnecessarily increase.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.