Method and apparatus for resizing images using the discrete cosine transform
US5845015A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 10, 1996 |
| Grant date | Dec 1, 1998 |
| Priority date | — |
| Expiry date | Oct 10, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/90
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus using the discrete cosine transform (DCT) to resize an image. To reduce an image, the method and apparatus exploits the convolution-multiplication property of the DCT to implement the anti-aliasing filter in the DCT domain, then the filtered coefficients are operated on to produce DCT coefficients of the reduced-size image. To increase an image, the DCT coefficients of the original image are operated on to produce coefficients of the larger image, then the convolution-multiplication property of the DCT is used to implement an anti-imaging filter. These DCT operations can be applied to the image as a whole or can be applied to non-overlapping blocks of the image.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.