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Open source OCR engine, accepting uncompressed TIFF files as input
License:Apache 2.0 License EXCEPT the tesseractTrainer.py, which is licensed with GPL
Platforms:Linux, Windows, MacOSX
Output Formats:ALTO (Analyzed Layout and Text Object)
Content type:Image

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Tesseract is probably the most accurate open source OCR engine available. Combined with the Leptonica Image Processing Library it can read a wide variety of image formats and convert them to text in over 60 languages. It was one of the top 3 engines in the 1995 UNLV Accuracy test. Between 1995 and 2006 it had little work done on it, but since then it has been improved extensively by Google.


Development of Tesseract is sponsored by Google. Its chief developer is Ray Smith.

Licensing and cost[edit]

Tesseract is an Open Source OCR engine, available under the Apache 2.0 license. It can be used directly, or (for programmers) using an API.


It was initially developed at HP during a 10 year period from 1984 to 1994. After a decade of minimal development it was released in 2005 for open source. Google acquired Tesseract in 2006 and currently maintains its development.

Platform and interoperability[edit]

  • The latest downloads for Linux and Windows are found on GoogleDrive. Older versions of Tesseract and its language packs are found on the discontinued Google Code download page.
  • The easiest way to install Tesseract on Mac OSX is with MacPorts. Once it is installed, you can install Tesseract by running the command sudo port install tesseract, and any language with sudo port install tesseract-<langcode>. A list of available langcodes can be found on the MacPorts Tesseract page.
  • Dependencies for running Tesseract include Autotools and Leptonica . The Windows version requires installation of Visual Studio. More information about required Ubantu libraries and links to specific requirements are on the Tesseract Wiki.
  • Other programs such as Scan Tailor, unpaper, ImageJ, Gimp or ImageMagick may be needed to properly prepare images for use in Tesseract.

Functional notes[edit]

Input supported[edit]

Any image readable by Leptonica is supported in Tesseract including BMP, PNM, PNG, JFIF, JPEG, and TIFF. GIF is not supported http://www.leptonica.com/library-overview.html.

Output generated[edit]

plain text, hOCR (HTML), PDF, invisible-text-only PDF, TSV and ALTO (XML)

Documentation and support[edit]

Included in[edit]


User Experiences[edit]

Development Activity[edit]

Source Commits : https://github.com/tesseract-ocr/tesseract/commits

Issues : https://github.com/tesseract-ocr/tesseract/issues