How to Convert a Latin Handwriting Recognition System to Arabic

Arabic handwriting recognition systems have been evaluated in public at the ICDAR conferences in 2005 and 2007. This contest provides well defined training data and unpublished test data, which makes the performance of those systems well comparable among each other. The development of the winning system of 2007 is described here in some detail. It is an HMM-based recognition system for Latin script that has been adapted to Arabic script. Only the most fundamental modifications have been applied to the system, like the definition of Arabic character models, and the change of the feature sequences to Arabic writing direction. Other important properties like writing line identification and the features themselves have not been changed. A straightforward optimization process with many small improvements has finally lead to a very competitive high performance Arabic handwriting recognition system. This shows the generality of the selected approach.