Image processing using hybrid lookup table
US8199363B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 24, 2007 |
| Grant date | Jun 12, 2012 |
| Priority date | — |
| Expiry date | Apr 9, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/40068
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An image processing method and an image processing apparatus converts a binary image into a grayscale image by increasing the size and information quantity of the binary image. The image processing method includes generating a plurality of lookup tables having multiple gray level values assigned to a predetermined pattern of the binary image such that the gray level is retrieved from the plurality of lookup tables depending on the context of the block being processed. The binary image may be converted into the grayscale image by applying the gray value of one of the plurality of lookup tables that corresponds to the context, such as the frequency components of the binary image. With this configuration, since the size and information quantity of an image can be reduced for transmission, it is possible to prevent deterioration of image quality when the image is restored, while also printing at a higher speed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.