System using data correlation for predictive encoding of video image data subject to luminance gradients and motion
US5812197A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 8, 1995 |
| Grant date | Sep 22, 1998 |
| Priority date | — |
| Expiry date | May 8, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/51
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An MPEG based video signal compression system reduces picture degradation caused by sub-optimal selection of a prediction mode. A disclosed method produces a compressed video output signal from a video input signal. The video input signal is converted (57) into pixel blocks. Then, a plurality of predicted blocks are formed (60) as representations of an input block. Each predicted block is produced by a different prediction function and has an associated Correlation Factor CF which indicates the degree of correlation between the input block and a predicted block. This factor is obtained (35) by subtracting a measure of a low frequency varying correlation component from an index of correlation. The Correlation Factors are compared (45), and a compressed block associated with the predicted block with the lowest CF value is selected as an output block. This process is repeated for the other input blocks, and the selected compressed output blocks are combined to form the output signal. The decision factor, CF, improves prediction mode selection and image motion estimation in the presence of image fading without the need for fading detection circuitry.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.