Method for compressing and decompressing digital image data
US5751860A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 3, 1996 |
| Grant date | May 12, 1998 |
| Priority date | — |
| Expiry date | Sep 3, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/593
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A compressing method consisting of generating a predicted value for the pixel of the digitized image to be compressed based on the values of at least two neighboring pixels is provided. After calculating the difference between the predicted value and the current pixel value, a prediction error is defined by a one-on-one mapping on the difference obtained. According to an advantageous feature of the mapping relationship, the required number of bits for representing the prediction error is less than that required for the difference per se. Afterwards, a parameter K is generated which is in proportion to the difference between the neighboring pixels used in prediction. According to the respective values of the parameter K, the next step is to encode each prediction error by assigning a variable-length Rice code to the prediction error of each pixel. If the Rice code formatted for a prediction error is longer than a predetermined length, the Rice code is disregarded and replaced by predetermined length of leading "1" bits followed by the value of current pixel.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.