Method and apparatus for image compression
US6353685B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 31, 1999 |
| Grant date | Mar 5, 2002 |
| Priority date | — |
| Expiry date | Aug 31, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T9/007
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An image compression apparatus for compressing image data provided to an input terminal and providing compressed data to an output terminal includes a 4×4 weighted digital cosine transformer (DCT) coupled to the input terminal and configured to convert the image data into weighted frequency data. A zigzag circuit is coupled to the DCT and configured to zigzag process the frequency data and generate create zigzag data. A Q-factor estimator is coupled to the DCT and configured to estimate the frequency data and generate a Q-factor. A DC coding circuit is coupled to the zigzag circuit and configured to code the zigzag data and generate a DC code. A quantization circuit is coupled to the zigzag circuit and the Q-factor estimator and configured to quantize the zigzag data based on the Q-factor and generate quantized data. A run-length coding circuit coupled to the DC coding circuit and the quantization circuit and configured to encode the quantized data to create variable length data as the compressed data to the output terminal. In this manner, the original image is compressed. While the invention is described with reference to specific hardware, the invention can also be impleme…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.