DjVu

DjVu (pronounced deja-vu) is a computer file format designed primarily to store scanned images. It features advanced technologies such as image layer separation, progressive loading, arithmetic coding, and lossy compression for bitonal images, allowing for high quality, readable images to be stored in a minimum of space.

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Progressive loading makes the format ideal for images served over the internet. DjVu has been promoted as an alternative to PDF, actually outperforming PDF on most scanned documents. This has led to its widespread use in distributing math books on file sharing networks. Like PDF, DjVu can contain an OCRed text layer, making it easy to perform cut and paste operations.

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The DjVu technology was originally developed by Yann Le Cun, L?on Bottou

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Patrick Haffner and Paul G. Howard at AT&T Laboratories

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in 1996. DjVu is an Open File Format. The file format specification is published as well as source code for the reference library. The ownership rights to the commercial development of the encoding software have been transferred to different companies over the years, including AT&T and LizardTech. The original authors maintain a GPLed implementation named "DjVuLibre".

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In 2002 the DjVu file format was chosen by the Internet archive as the format in which its Million Book Project provides scanned public domain books online (along with TIFF and PDF).

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Computer: A computer is a device or for processing information from data according to a program — a compiled list of instructions. The information to be processed may represent numbers, text, pictures, or sound, amongst many other types....

File format: A file format is a particular way to encode information for storage in a computer file....

Arithmetic coding: Arithmetic coding is a method for lossless data compression. It is a form of entropy encoding, but where other entropy encoding techniques separate the input message into its component symbols and replace each symbol with a code word, arithmetic coding encodes the entire message into a single numbe...