Method for compression and expansion of display data
US7574056B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 2004 |
| Grant date | Aug 11, 2009 |
| Priority date | — |
| Expiry date | Oct 31, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/91
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A display data compression method can execute both irreversible compression and reversible compression, wherein display data are divided into a plurality of two-dimensional blocks, each of which is subjected to compression. In the irreversible compression, display data of each block are subjected to discrete cosine transform, quantization using a quantization table, one-dimensional rearrangement, and Huffman coding using one-dimensional Huffman table. In the reversible compression, display data of each block are subjected to scanning and compression, which are repeatedly performed by changing the scanning method therefor, so as to produce compressed data having the smallest number of effective bits. In expansion, the compressed data are decoded so that the decoded data are combined together over the blocks, thus restoring the original display data.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.