JBIG is an early
lossless image compression
Image compression is a type of data compression applied to digital images, to reduce their cost for storage or transmission. Algorithms may take advantage of visual perception and the statistical properties of image data to provide superior re ...
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/
IEC
The International Electrotechnical Commission (IEC; in French: ''Commission électrotechnique internationale'') is an international standards organization that prepares and publishes international standards for all electrical, electronic and r ...
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 Co ...
recommendation T.82 in March 1993.
It is widely implemented in fax machines. Now that the newer
bi-level image
A binary image is one that consists of pixels that can have one of exactly two colors, usually black and white. Binary images are also called ''bi-level'' or ''two-level'', Pixelart made of two colours is often referred to as ''1-Bit'' or ''1b ...
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
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 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
The is a group of autonomous Japanese multinational companies in a variety of industries.
Founded by Yatarō Iwasaki in 1870, the Mitsubishi Group historically descended from the Mitsubishi zaibatsu, a unified company which existed from 1870 ...
, 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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See also
ISO/IEC JTC 1/SC 29
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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