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OCRAD(1) User Commands OCRAD(1)


ocrad - command line text recognition tool


ocrad [options] [files]


GNU Ocrad is an OCR (Optical Character Recognition) program based on a feature extraction method. It reads images in pbm (bitmap), pgm (greyscale) or ppm (color) formats and produces text in byte (8-bit) or UTF-8 formats. The pbm, pgm and ppm formats are collectively known as pnm.

Ocrad includes a layout analyser able to separate the columns or blocks of text normally found on printed pages.

For best results the characters should be at least 20 pixels high. If they are smaller, try the --scale option. Scanning the image at 300 dpi usually produces a character size good enough for ocrad. Merged, very bold or very light (broken) characters are normally not recognized correctly. Try to avoid them.


display this help and exit
output version information and exit
append text to output file
try '--charset=help' for a list of names
try '--filter=help' for a list of names
user-defined filter, see manual for format
force overwrite of output file
output format (byte, utf8)
invert image levels (white on black)
perform layout analysis
place the output into <file>
suppress all messages
scale input image by [1/]<n>
try '--transform=help' for a list of names
threshold for binarization (0-100%)
cut input image by given rectangle
be verbose
export results in ORF format to <file>

If no files are specified, ocrad reads the image from standard input. If the -o option is not specified, ocrad sends text to standard output.

Exit status: 0 for a normal exit, 1 for environmental problems (file not found, invalid flags, I/O errors, etc), 2 to indicate a corrupt or invalid input file, 3 for an internal consistency error (eg, bug) which caused ocrad to panic.


Report bugs to
Ocrad home page:
General help using GNU software:


Copyright © 2019 Antonio Diaz Diaz. License GPLv2+: GNU GPL version 2 or later <>
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.


The full documentation for ocrad is maintained as a Texinfo manual. If the info and ocrad programs are properly installed at your site, the command

info ocrad

should give you access to the complete manual.

January 2019 ocrad 0.27