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.\"     Title: unicharset_extractor
.\"    Author: [see the "AUTHOR" section]
.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
.\"      Date: 01/21/2019
.\"    Manual: \ \&
.\"    Source: \ \&
.\"  Language: English
.\"
.TH "UNICHARSET_EXTRACTOR" "1" "01/21/2019" "\ \&" "\ \&"
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.SH "NAME"
unicharset_extractor \- extract unicharset from Tesseract boxfiles
.SH "SYNOPSIS"
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\fBunicharset_extractor\fR \fI[\-D dir]\fR \fIFILE\fR\&...
.SH "DESCRIPTION"
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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:
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.if n \{\
.RS 4
.\}
.nf
unicharset_extractor fontfile_1\&.box fontfile_2\&.box \&.\&.\&.
.fi
.if n \{\
.RE
.\}
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The unicharset will be put into the file \fIdir/unicharset\fR, or simply \fI\&./unicharset\fR if no output directory is provided\&.
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Tesseract also needs to have access to character properties isalpha, isdigit, isupper, islower, ispunctuation\&. all of this auxilury data and more is encoded in this file\&. (See unicharset(5))
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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\&.
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\fBNOTE\fR 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\&.
.SH "SEE ALSO"
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tesseract(1), unicharset(5)
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\m[blue]\fBhttps://github\&.com/tesseract\-ocr/tesseract/wiki/TrainingTesseract\fR\m[]
.SH "HISTORY"
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unicharset_extractor first appeared in Tesseract 2\&.00\&.
.SH "COPYING"
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Copyright (C) 2006, Google Inc\&. Licensed under the Apache License, Version 2\&.0
.SH "AUTHOR"
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The Tesseract OCR engine was written by Ray Smith and his research groups at Hewlett Packard (1985\-1995) and Google (2006\-present)\&.