Join GitHub today
GitHub is home to over 28 million developers working together to host and review code, manage projects, and build software together.Sign up
Automatically exported from code.google.com/p/tesseractindic
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Introduction ============ This package contains the Tesseract Open Source OCR Engine. Orignally developed at Hewlett Packard Laboratories Bristol and at Hewlett Packard Co, Greeley Colorado, all the code in this distribution is now licensed under the Apache License: ** Licensed under the Apache License, Version 2.0 (the "License"); ** you may not use this file except in compliance with the License. ** You may obtain a copy of the License at ** http://www.apache.org/licenses/LICENSE-2.0 ** Unless required by applicable law or agreed to in writing, software ** distributed under the License is distributed on an "AS IS" BASIS, ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. ** See the License for the specific language governing permissions and ** limitations under the License. Other Dependencies and Licenses: ================================ The Aspirin/MIGRAINES system is no longer required. Tesseract can also make use of the libtiff library. (www.libtiff.org) Without libtiff, Tesseract can only read uncompressed and G3 compressed TIFF files. History: ======== The engine was developed at Hewlett Packard Laboratories Bristol and at Hewlett Packard Co, Greeley Colorado between 1985 and 1994, with some more changes made in 1996 to port to Windows, and some C++izing in 1998. A lot of the code was written in C, and then some more was written in C++. Since then all the code has been converted to at least compile with a C++ compiler. Currently it builds under Linux with gcc2.95 and under Windows with VC++6. The C++ code makes heavy use of a list system using macros. This predates stl, was portable before stl, and is more efficent than stl lists, but has the big negative that if you do get a segmentation violation, it is hard to debug. Another "feature" of the C/C++ split is that the C++ data structures get converted to C data structures to call the low-level C code. This is ugly, and the C++izing of the C code is a step towards eliminating the conversion, but it has not happened yet. Directory Structure (ordered by dependency): ============================================ ccmain Top-level code. The main program resides in tesseractmain.cpp. display An "editor" to view and operate on the internal structures. (Requires a working viewer - batteries not included.) wordrec The word-level recognizer. textord The module that organizes(orders) text into lines and words. classify The low-level character classifiers. ccstruct Classes to hold information about a page as it is being processed. viewer The client side of a client server viewing system. Unfortunately, at this time, the server side is not available. image Image class and processing functions. dict Language model code. cutil Code for file I/O, lists, heaps etc, from the old C code. ccutil Somewhat newer code for lists, memory allocation etc from the old C++ code. About the Engine ================ This code is a raw OCR engine. It has NO PAGE LAYOUT ANALYSIS, NO OUTPUT FORMATTING, and NO UI. It can only process an image of a single column and create text from it. It can detect fixed pitch vs proportional text. Having said that, in 1995, this engine was in the top 3 in terms of character accuracy, and it compiles and runs on both Linux and Windows. As of 2.0, Tesseract is fully unicode (UTF-8) enabled, and can recognize 6 languages "out of the box." Code and documentation is provided for the brave to train in other languages. See code.google.com/p/tesseract-ocr for more information on training. Using the Engine ================ Windows: The executable must reside in the same directory as the tessdata directory The command line is: tesseract <image.tif> <output> [-l langid] A windows executable (tesseract.exe) is included in the distribution, but may not work for you unless you also have the correct mfc and crt dlls. There is also a tessdll.dll, which you can use to run tesseract from your own program, but you may be better off building it yourself. Non-Windows: You have to tell Tesseract through a standard unix mechanism where to find its data directory. You must either: ./configure make make install to move the data files to the standard place, or: export TESSDATA_PREFIX="directory in which your tessdata resides/" (or equivalent) in your .profile or whatever or setenv to set the environment variable. Note that the directory must end in a / HAVING tesseract and tessdata IN THE SAME DIRECTORY DOES NOT WORK ANY MORE. The command line is: tesseract <image.tif> <output> [-l langid] ***Please ignore the install error related to java in the end. All Systems: The image file requires a .tif extension for its type to be recognized correctly. If a file exists with the .tif extension replaced by .uzn, then it will be interpreted as a UNLV-style zone file. (See www.isri.unlv.edu for details of the zone files.) langid may be one of the codes defined in ISO 639-3, and you must download the corresponding data files into your tessdata directory.