Addons
Here you can find additional packages for document analysis problems that are too specific to be included in the Gamera core distribution. These packages are provided as Gamera toolkits, which require a working Gamera installation. They can be installed like Gamera itself with the command
python setup.py build && sudo python setup.py install
Text document recognition
The OCR Toolkit is meant to help building optical character recognition (OCR) systems for standard text documents. It provides:
- a flexible mechanism for plugging in custom page segmentation algorithms
- heuristic rules for dealing with diacritics, and for disambiguation of commonly confused roman characters
- a ready-to-run python script ocr4gamera which acts as a very basic OCR-system
Staff line removal
An important preprocessing step in Optical Music Recognition (OMR) is the detection and removal of the staff lines. This can be done with the MusicStaves Toolkit. It offers the following functionality:
- different algorithms for staff detection and removal
- an abstract interface for adding custom staff detection and removal algorithms
- evaluation algorithms for measuring staff removal quality
- deformation algorithms for creating test images for evaluation
Lute tablature recognition
The OTR Toolkit is a complete application for the recognition of historic lute tablature prints. It offers the following functionality:
- recognition of French, Italian, German lute tablature, and of modern guitar tablature (aka "spanish lute tablature")
- conversion of the tablature to music
Psaltic neume notation recognition
The Psaltiki Toolkit is a complete application for the recognition of the post 1800 neume based chant notation of the eastern church. It offers the following functionality:
- page layout analysis and baseline detection
- neume recognition and neume layout analysis
- generation of a machine readable output code
FFTW wrapper
The guiron toolkit is a wrapper around the discrete Fourier transform library FFTW. An old version of the toolkit can be downloaded from SourceForge with
svn co https://gamera.svn.sourceforge.net/svnroot/gamera/trunk/guiron guiron
This toolkit was written for the old 2.x version of Gamera, which had used image constructors that are now incompatible with version 3.x. Help on porting this toolkit to the current Gamera version is welcome (see the Gamera TODO list).
Meanwhile, SciPy/NumPy includes a wrapper for FFTW, so this might be a more convenient option to implement DFT based algorithms in Gamera.
Image vectorization
The vector toolkit was meant for polygonization of a raster image and for manipulating the resulting vector image. It used the potrace algorithm, which only works on closed curves and thus can only be applied to outline images, but not to skeleton images.
The code is in a pre-alpha state, but could be used as a starting point for working on a vector toolkit. Help for a vector toolkit is welcome (see the Gamera TODO list). The old code can be downloaded from SourceForge with
svn co https://gamera.svn.sourceforge.net/svnroot/gamera/trunk/vector vector