System and method for compressing and decompressing images
US6282322A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 3, 1998 |
| Grant date | Aug 28, 2001 |
| Priority date | — |
| Expiry date | Dec 3, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/61
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
This invention relates to systems and methods for increasing image compression. The systems and methods are improvements applicable to encoder/decoders which compress images by, inter alia, transforming non-overlapping independent blocks of pixels into a frequency domain and then quantizing the resulting frequency domain coefficients. The invention achieves increased compression by predicting low frequency coefficients of a block from, preferably, the average intensities, or zero frequency coefficients, of the block and its adjacent blocks. In an encoder, the low frequency coefficients are predicted, are then subtracted from the actual transform coefficients, and the difference coefficients are transmitted to a decoder. In the decoder, the low frequency coefficients are again predicted, are added to the received difference coefficients, and the resulting actual transform coefficients are used to reconstruct an image.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.