Investigation of Ancient Manuscripts based on Multispectral Imaging

This work is concerned with the digitization and analysis of historical documents. The investigation of the documents has been conducted in three successive interdisciplinary projects. The team involved in the projects consists of philologists, chemists and computer scientists specialized in the field of digital image processing. The manuscripts investigated are partially degraded since they have been infected by mold, are corrupted by background clutter or contain faded-out or even erased writings. Since these degradations impede a transcription by scholars and worsen the performance of automated document image analysis techniques, the documents have been imaged with a portable multispectral imaging system. By using this non-invasive investigation technique, the contrast of the faded out characters can be increased, compared to ordinary white light illumination. Post-processing techniques, such as dimension reduction tools, can be used to gain a further legibility increase. The resulting images are used as a basis for further document analysis methods. These methods have been especially designed for the historical documents investigated and involve Optical Character Recognition and writer identification. This paper presents an overview on selected methods that have been developed in the projects.