PDF OCR is a simple drag-and-drop utility that converts PDFs and images into text documents. It uses advanced OCR (optical character recognition) technology to extract the text of the PDF or image. This is particularly useful for dealing with PDFs and images that were created via a scan-to-PDF function in a scanner or photo copier. It uses the Tesseract engine to perform OCR, and currently supports over 20 languages for OCR.
GNU Ocrad is an OCR (Optical Character Recognition) program and library based on a feature extraction method. It reads images in pbm (bitmap), pgm (greyscale), or ppm (color) formats and produces text in byte (8-bit) or UTF-8 formats. It also includes a layout analyzer that is able to separate the columns or blocks of text normally found on printed pages. Ocrad can be used as a stand-alone console application, or as a backend to other programs.
getxbook is a collection of tools to download books from websites. There are tools to download from Google Books' "book preview", Amazon's "look inside the book", and Barnes and Noble's "book viewer". There is an optional GUI written in Tcl/Tk, and some shell scripts using OCR to create plain text or searchable PDFs and DjVu files from the downloaded books.
OCRFeeder is a document layout analysis and optical character recognition application. It is able to automatically outline a document image's contents, distinguish between graphics and text and perform OCR over the latter. It can export to several formats, its main one being ODT. OCRFeeder has a GTK+ graphical user interface that allows the user to control the application and, for example, edit and correct the automatic recognition. It can also be used from the command line for automation.
Character Recognition is an Android app that allows the user to take a photo (or use existing image files on the device) and then apply the Tesseract OCR engine to extract the text in the photo. It is currently supporting English text, but other language support will be added in the future.