tesseract

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 supports a wide variety of languages.

Tesseract doesn't have a built-in GUI, but there are several available from the 3rdParty page.

Quick Start

$ alias tesseract='docker run --rm -v `pwd`:/data -w /data vimagick/tesseract'
$ tesseract input.png output -l eng --psm 3
$ cat output.txt