2016 12th IAPR Workshop on Document Analysis Systems Recognition of Greek Polytonic on Historical Degraded Texts using HMMs Vassilis Katsouros1, Vassilis Papavassiliou1, Fotini Simistira3,1, and Basilis Gatos2 1Institute for Language and Speech Processing (ILSP) Athena Research and Innovation Center, Athens, Greece Email: {vpapa, fotini, vsk}@ilsp.gr 2Computational Intelligence Laboratory, Institute of Informatics and Telecommunications 1DWLRQDO&HQWHUIRU6FLHQWLILF5HVHDUFK³'HPRNULWRV´$WKHQV*UHHFH
[email protected] 3DIVA Research Group University of Fribourg, Switzerland Email:
[email protected] Abstract² Optical Character Recognition (OCR) of ancient SODFHGDERYHWKHYRZHOVWKHDFXWHDFFHQWHJȐWRPDUNKLgh Greek polytonic scripts is a challenging task due to the large pitch on a short vowel, the grave accent, e.g. , to mark normal number of character classes, resulting from variations of or low pitch, and the circumflex, e.g. ઼, to mark high and diacritical marks on the vowel letters. Classical OCR systems falling pitch within one syllable; the second category involves require a character segmentation phase, which in the case of two breathings placed also above vowels, the rough breathing, Greek polytonic scripts is the main source of errors that finally e.g. ਖ, to indicate a voiceless glottal fricative (/h/) before a affects the overall OCR performance. This paper suggests a vowel and the smooth breathing, e.g. ਕ, to indicate the absence character segmentation free HMM-based recognition system and RIKWKHGLDHUHVLVDSSHDUVRQWKHOHWWHUVȚDQGȣHJȧDQGȨ