JBIG is an early

lossless Lossless compression is a class of data compression that allows the original data to be perfectly reconstructed from the compressed data with no loss of information. Lossless compression is possible because most real-world data exhibits statistic ...

image compression standard from the

Joint Bi-level Image Experts Group The Joint Bi-level Image Experts Group (JBIG) is a group of experts nominated by national standards bodies and major companies to work to produce standards for bi-level image coding. The "joint" refers to its status as a committee working on both I ...

, standardized as

ISO ISO is the most common abbreviation for the International Organization for Standardization. ISO or Iso may also refer to: Business and finance * Iso (supermarket), a chain of Danish supermarkets incorporated into the SuperBest chain in 2007 * Iso ...

/ IEC standard 11544 and as

ITU-T The ITU Telecommunication Standardization Sector (ITU-T) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU). It is responsible for coordinating standards for telecommunications and Information Comm ...

recommendation T.82 in March 1993. It is widely implemented in fax machines. Now that the newer bi-level image compression standard

JBIG2 JBIG2 is an image compression standard for bi-level images, developed by the Joint Bi-level Image Experts Group. It is suitable for both lossless and lossy compression. According to a press release from the Group, in its lossless mode JBIG2 ty ...

has been released, JBIG is also known as JBIG1. JBIG was designed for compression of binary images, particularly for

fax Fax (short for facsimile), sometimes called telecopying or telefax (the latter short for telefacsimile), is the telephonic transmission of scanned printed material (both text and images), normally to a telephone number connected to a printer o ...

es, but can also be used on other images. In most situations JBIG offers between a 20% and 50% increase in compression efficiency over Fax Group 4 compression, and in some situations, it offers a 30-fold improvement. JBIG is based on a form of

arithmetic coding Arithmetic coding (AC) is a form of entropy encoding used in lossless data compression. Normally, a string of characters is represented using a fixed number of bits per character, as in the ASCII code. When a string is converted to arithmetic ...

developed by IBM (known as the Q-coder) that also uses a relatively minor refinement developed by Mitsubishi, resulting in what became known as the QM-coder. It bases the probability estimates for each encoded bit on the values of the previous bits and the values in previous lines of the picture. JBIG also supports progressive transmission, which generally incurs a small overhead in bit rate (around 5%).

Patents

Doubts about patent licence requirements for JBIG1 implementations by IBM, Mitsubishi and AT&T prevented the codec from being widely implemented in open-source software. For example, as of 2012, none of the commonly used web browsers supported it. Since 2012, there are now no more JBIG1 patents in force – the last ones to expire were Mitsubishi's patents in Canada and Australia (on 25 February 2011) and in the United States (on 4 April 2012).JBIG1 patent information
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References

External links

JBIG-KIT
– a free C implementation of the JBIG encoder and decoder
ISO/IEC 11544
* ITU-T Recommendation
T.82T.85
* – Content Feature Schema for Internet Fax (V2) * – File Format for Internet Fax Lossless compression algorithms Lossy compression algorithms Graphics file formats T.82 ISO standards IEC standards Image compression {{graphics-software-stub

Patents

See also

References

External links