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 statisti ...
image compression
Image compression is a type of data compression applied to digital images, to reduce their cost for computer data storage, storage or data transmission, transmission. Algorithms may take advantage of visual perception and the statistical properti ...
standard from the
Joint Bi-level Image Experts Group, standardized as
ISO
The International Organization for Standardization (ISO ; ; ) is an independent, non-governmental, international standard development organization composed of representatives from the national standards organizations of member countries.
Me ...
/
IEC standard 11544 and as
ITU-T
The International Telecommunication Union Telecommunication Standardization Sector (ITU-T) is one of the three Sectors (branches) of the International Telecommunication Union (ITU). It is responsible for coordinating Standardization, standards fo ...
recommendation T.82 in March 1993.
It is widely implemented in fax machines. Now that the newer
bi-level image compression standard
JBIG2 has been released, JBIG is also known as JBIG1. JBIG was designed for compression of binary images, particularly for
faxes, 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 (computer science), string of characters is represented using a fixed number of bits per character, as in the American Standard Code for In ...
developed by
IBM
International Business Machines Corporation (using the trademark IBM), nicknamed Big Blue, is an American Multinational corporation, multinational technology company headquartered in Armonk, New York, and present in over 175 countries. It is ...
(known as the Q-coder) that also uses a relatively minor refinement developed by
Mitsubishi
The is a group of autonomous Japanese multinational companies in a variety of industries.
Founded by Yatarō Iwasaki in 1870, the Mitsubishi Group traces its origins to the Mitsubishi zaibatsu, a unified company that existed from 1870 to 194 ...
, 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).]
See also
* ISO/IEC JTC 1/SC 29
* JBIG2
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
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