Method and apparatus for converting image information
US6658157B1 · kind B1 · utility
82Cited by
4References
19Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jun 27, 2000 |
| Grant date | Dec 2, 2003 |
| Priority date | — |
| Expiry date | Jan 19, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/70
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A technique is disclosed for reducing the bit rate of a bit stream coded into a compressed form according to the MPEG-2 standard, without causing significant degradation in image quality of a decoded image. An inverse DCT converter dequantizes a MPEG-2 bit stream and outputs resultant discrete cosine transform coefficients for each DCT block. A band limiter replaces the values of high-frequency components of the discrete cosine transform coefficients in the horizontal direction, with 0. A quantizer quantizes the discrete cosine transform coefficients using a quantization step value different from the original value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.