Adaptive quantization of grayscale images
US6323956A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 10, 1996 |
| Grant date | Nov 27, 2001 |
| Priority date | — |
| Expiry date | Dec 10, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K2215/0057
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method of generating an M-bit grayscale image from an N-bit grayscale image, where 1<M<N, includes the steps of: for each pixel in the N-bit image, determining a threshold, based on the values of neighboring pixels, for generating the most significant bit (MSB) of the M-bit image, and determining thresholds, based on the threshold determined in step i) and the values of surrounding pixels, for each successive less significant bit(s) (LSB) of the M-bit image. The thresholds are used to quantize the pixels in the N-bit image to produce the M-bit image. The resulting M-bit image can be displayed on a multilevel display device for good readability, and the most significant bit of the M-bit image can be archived and printed on a binary printer thereby minimizing long term storage requirements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.