Method for adaptive quantization by multiplication of luminance pixel blocks by a modified, frequency ordered hadamard matrix
US5786856A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 19, 1996 |
| Grant date | Jul 28, 1998 |
| Priority date | — |
| Expiry date | Mar 19, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/15
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method for spatial compression of a digital video picture to obtain the quantizer step size so as to avoid over "lossy" reconstruction and loss of detail. The first step is dividing the picture into a plurality of macroblocks, for example, 16.times.16 macroblocks, each macroblock having luminance or chrominance pixel blocks, for example four 8.times.8 pixel blocks. This is followed by multiplying each luminance pixel block by a modified frequency ordered Hadamard matrix to yield a first dimension of each luminance pixel block. The first dimension of each pixel block is then multiplied by the inverse of the modified frequency ordered Hadamard matrix to yield a second dimension of each luminance pixel block. The second dimension of the pixel luminance block is then weighted against a weight matrix, and the individual weighted terms are summed for each pixel block. The minimum of the weighted terms is selected. This minimum is used to detect the edge or texture of the macroblock, e.g., for setting the quantizer step size.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.