Image transformations in the compressed domain
US6298166A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 30, 1998 |
| Grant date | Oct 2, 2001 |
| Priority date | — |
| Expiry date | Mar 30, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/90
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Image processing techniques which involve direct manipulation of the compressed domain representation of an image to achieve the desired spatial domain processing without having to go through a complete decompression and compression process. The techniques include processing approaches for performing the eight operations in D.sub.4 (the dihedral group of symmetries of a square) on JPEG images using the discrete cosine transform (DCT) domain representation of the images directly. For a task such as image rotation by 90.degree. (an operation in D.sub.4), DCT-domain based methods can yield nearly a five-fold increase in speed over a spatial-domain based technique. These simple compressed-domain based processing techniques are well suited to the imaging tasks that are needed in a JPEG-based digital still-camera system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.