Raster image data compression method and system
US5649074A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 31, 1995 |
| Grant date | Jul 15, 1997 |
| Priority date | — |
| Expiry date | Jan 31, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/503
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Data compression apparatus includes a current block of data bytes and a logic circuit for determining whether each byte in the current block is the same or different from a seed value. An encoding circuit produces a compressed version of the current block, which includes Command bytes and continuous literal data bytes from the current block. Each Command byte has an encoding identifier, an offset count and a data segment replacement count. Each offset count and data segment replacement count have, respectively, maximum bit sizes (and values). The encoding circuit responds to an indication that a data segment (1) differs from the seed value and (2) is followed by a series of contiguous data segments that are different from the seed value, by causing (a) a first Command byte to manifest a data segment replacement count of the maximum value and an offset count of 0 and to be followed by at least one of the contiguous data segments from the series. Thereafter, a next Command byte occurs if the remaining number of contiguous data segments exceeds the maximum value of the data segment replacement count. The next Command byte(s) each manifest maximum value data segment replacement counts …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.