UNICHARSET_EXTRACTOR(1) Manual Page

unicharset_extractor FILE…

Tesseract needs to know the set of possible characters it can output. To generate the unicharset data file, use the unicharset_extractor program on the same training pages bounding box files as used for clustering:

Tesseract needs to have access to character properties isalpha, isdigit, isupper, islower, ispunctuation. This data must be encoded in the unicharset data file. Each line of this file corresponds to one character. The character in UTF-8 is followed by a hexadecimal number representing a binary mask that encodes the properties. Each bit corresponds to a property. If the bit is set to 1, it means that the property is true. The bit ordering is (from least significant bit to most significant bit): isalpha, islower, isupper, isdigit, ispunctuation. (See unicharset(5))

If your system supports the wctype functions, these values will be set automatically by unicharset_extractor and there is no need to edit the unicharset file. On some older systems (eg Windows 95), the unicharset file must be edited by hand to add these property description codes.

NOTE The unicharset file must be regenerated whenever inttemp, normproto and pffmtable are generated (i.e. they must all be recreated when the box file is changed) as they have to be in sync. This is made easier than in previous versions by running unicharset_extractor before mftraining and cntraining, and giving the unicharset to mftraining.

tesseract(1), unicharset(5)

unicharset_extractor first appeared in Tesseract 2.00.

Copyright © 2006, Google Inc. Licensed under the Apache License, Version 2.0