System and method of a fast inverse discrete cosine transform and video compression/decompression systems employing the same
US5883823A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 15, 1997 |
| Grant date | Mar 16, 1999 |
| Priority date | — |
| Expiry date | Jan 15, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T9/007
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An array of DCT transform coefficients are converted to a two-dimensional array of spatial data in a video compression or decompression system. The array of DCT transform coefficients are divided into two groups. A regional IDCT algorithm is applied to all coefficients, both non-zero and zero, of the first group, while IDCT computation is applied to only non-zero coefficients of the second group. The results of the operations are then combined and/or mapped to form the output array of spatial data. In one specific implementation wherein an 8.times.8 array of DCT coefficients are to be transformed, the first region is defined by the first quadrant of coefficients in the 8.times.8 array. A regional IDCT algorithm is applied to both zero and non-zero coefficients in the first quadrant. The non-zero coefficients in the remaining three quadrants are calculated directly, and the results of the direct calculations are combined with the results of the regional IDCT algorithm applied to the first quadrant coefficients. The resulting values are then mapped to the output matrix.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.