JBIG2 is a relatively new image compression standard that was first published as an international standard in 2000. It was a modern option for both lossless and lossy image compression. The standard is designed to compress images better than the traditional JBIG and Fax Group 4 standards previously implemented for bi-level or black and white images. JBIG2 compression reduces files to as small as one fifth of  the size of pictures saved under traditional formats. When black and white images are compressed with the JBIG2 algorithm, compression ratios can be 100:1 when compared to traditional TIFF image formats.

What Type of Imagery is Suitable for the JBIG2 Compression Standard?

JBIG2 compression is primarily used for black and white imagery. This is because the algorithm relies on symbol recognition to get a high degree of file compression. The compression algorithm scans image files for similarly arranged shapes, it then uses associated symbols to find similarities within the image. Industry now finds the algorithm useful for scanning and storing black and white documents for archival purposes, as a significant amount of space is saved in comparison to traditional file formats.

What Are the Steps of JBIG2 Compression?

Step 1 – The compression algorithm identifies the connected components in the image (normally four or eight are found per image).

Step 2 – The algorithm then places components in a “similarity” class that uses an image template as a representative, with the location of each instance being recorded.

Step 3 – The image templates, index, and location are then compressed and written to a file. The compression uses an arithmetic coding with Huffmann or arithmetic encoding on the image file’s location information.

Where Can JBIG2 Image Conversion and Viewers be Found?

There are several companies that offer JBIG2 image viewers and conversion software, including SDK support for the Java platform. The Levigo company has released an open source Java ImageIO plugin that allows access to and manipulation of images that are encoded using the JBIG 2 image compression standard. The plugin features include the ability to decode JBIG2 pictures, full support of the ISO standard (includin MQ, Huffman, and arithmetic coding), no JNI code add-ons with the library being written purely in Java, and support for shared data segments. There are also several commercially produced JBIG2 image conversions and viewing applications on the market that vary in cost and capability depending on individual requirements.