Method for speeding up JPEG quantization operations in image compression
US6009207A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 18, 1997 |
| Grant date | Dec 28, 1999 |
| Priority date | — |
| Expiry date | Nov 18, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T9/007
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method for speeding up JPEG quantization operations in image compression for discrete cosine transform encoding operations in JPEG image compression. The quantization calculations are performed to obtain descriptors for Huffman encoding. The quantization calculations utilize a modified quantization table which is derived from an original quantization table by inversing each element of the original quantization table and then mutiplying 2.sup.n and then rounding off. The matrix composed by discrete cosine transform coefficients multiplies the modified quantization table to derive a new matrix. Then, each element of the new matrix is right shifted n bits to derive quantized discrete cosine transform coefficients. Then, Huffman encoding is performed to accomplish discrete cosine transform encoding.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.