Adaptive quantization of video based on edge detection
US5724097A · kind A · utility
66Cited by
5References
9Claims
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Key dates
| Filing date | Oct 18, 1994 |
| Grant date | Mar 3, 1998 |
| Priority date | — |
| Expiry date | Oct 18, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/60
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A video signal is divided into blocks, and an orthogonal transform is performed on each block to obtain transformed coefficients. Of the transformed coefficients thus obtained, dominant transformed coefficients are selected from a low-frequency area and a high-frequency area, and based on the dominant transformed coefficients, an evaluation value is calculated, using which value a specific pattern in the video signal is detected. Based on the specific pattern thus detected, an optimum quantization step size is decided, and the transformed coefficients are adaptively quantized, thus preventing image quality degradation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.