Jpeg-compressed file creating method
US7599564B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 12, 2004 |
| Grant date | Oct 6, 2009 |
| Priority date | — |
| Expiry date | Jul 15, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/60
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Image feature values Va and Vb are derived from image data, coefficients C and D are determined based on the image feature values Va and Vb, and an approximate expression expressed with the file size Sfj of the JPEG compression file and the quantization data coefficient value Aqt is derived. Next, by designating the file size of a desired predetermined JPEG compression file based on the approximate expression, the quantization data coefficient value Aqt is derived, and a first quantization table as a reference is multiplied by the quantization data coefficient value Aqt, whereby a second quantization table is obtained. Then, using the second quantization table, the image data is actually JPEG-compressed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.