Samuel W. Flint 7ad55fa0d0 Added tools for Tesseract training | 8 years ago | |
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data | 8 years ago | |
lib | 8 years ago | |
samples | 8 years ago | |
tesseract-ocr | 8 years ago | |
tools | 8 years ago | |
jTessBoxEditor.jar | 8 years ago | |
readme.html | 8 years ago | |
train | 8 years ago | |
train.bat | 8 years ago | |
versionchanges.txt | 8 years ago |
jTessBoxEditor is a box
editor and trainer for Tesseract OCR,
providing editing of box data of both Tesseract 2.0x and 3.0x formats and full automation
of Tesseract training. It can read common image formats, including multi-page TIFF.
jTessBoxEditor is released and distributed under the Apache License, v2.0.
Java Runtime
Environment 7.0 or later.
Double-click on the JAR file to launch the program, or execute the following command:
java -Xms128m -Xmx1024m -jar jTessBoxEditor.jar
You will need to provide the TIFF/Box files as input to the editor. Images to be
used in training should be of 300 DPI and 1 bpp (bit per pixel) black&white
or 8 bpp grayscale, uncompressed TIFF format; box files, encoded in UTF-8 format,
are generated by Tesseract executables with appropriate command-line options (see
Tesseract Training Wiki). Or
they both can be created using the built-in TIFF/Box Generator.
The following hotkeys are available in Box View for ease of editing:
Holding Shift when using hotkeys multiplies movement speed by 10.
Pressing Enter or ESC when editing character focuses the box editor.
Note that the coordinate system used in the box file has (0,0) at the bottom-left;
on computer graphics devices, however, (0,0) is defined as top-left. jTessBoxEditor
uses and displays in the graphics device coordinates. The edited box files are still
read and written in proper format.
The generator produces, for a given input UTF-8 text file, a TIFF/Box pair of files
suitable for training with Tesseract. The generated image is, depending on anti-aliasing
mode enabled, a binary or grayscale, uncompressed multi-page TIFF with 300 DPI resolution.
Letter tracking, or spacing between characters, can be adjusted to eliminate bounding
box overlapping issues. Note that the coordinates of some boxes could be slightly
different (by 1 or 2 pixels) from the ones that would have been generated by Tesseract
itself; nevertheless, the generated box file can be used to validate the one created
by Tesseract with the use of a Unicode-compatible file compare tool, such as
WinMerge.
Tips: Experiments indicate that the quality of
training with images created by TIFF/Box Generator is higher with font
sizes 24pt or greater and with some noise added.
Combining symbols or diacritics, like those found in Devanagari or Indic scripts,
that need to be combined with the main, base character can be specified by the user
in a UTF-8 text file, specifically data/combiningsymbols.txt
, which is
read by the generator. This setup gives the users the flexibility in
defining combining symbols/diacritics for their language scripts.
Automated training is provided in latest version. Tesseract Windows training executables
are bundled with the program; for other platforms, you will need to
build them. Place all required source training data files, prefixed with
an appropriate language code, in a specified directory (check samples
folder for examples). The training operation can also be automated using the enclosed
train.ps1
Windows PowerShell script.
The Merge TIFF function can save multiple images containing text of the
same font into a single multi-page TIFF file to be used for training.
A conversion function is included to convert numeric character reference (NCR) and
escape sequence in the Character text field to Unicode characters.
If there is any question, please post in
VietOCR Forums.