NAME

ocrad - command line text recognition tool

SYNOPSIS

ocrad [options] [files]

DESCRIPTION

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

OPTIONS

-h, --help: display this help and exit
-V, --version: output version information and exit
-a, --append: append text to output file
-c, --charset=<name>: try '--charset=help' for a list of names
-e, --filter=<name>: try '--filter=help' for a list of names
-E, --user-filter=<file>: user-defined filter, see manual for format
-f, --force: force overwrite of output file
-F, --format=<fmt>: output format (byte, utf8)
-i, --invert: invert image levels (white on black)
-l, --layout: perform layout analysis
-o, --output=<file>: place the output into <file>
-q, --quiet: suppress all messages
-s, --scale=[-]<n>: scale input image by [1/]<n>
-t, --transform=<name>: try '--transform=help' for a list of names
-T, --threshold=<n>: threshold for binarization (0.0-1.0)
-u, --cut=<l,t,w,h>: cut the input image by the rectangle given
-v, --verbose: be verbose
-x, --export=<file>: export results in ORF format to <file>

If no files are specified, or if a file is '-', ocrad reads the image from standard input. If the option -o 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 (e.g., bug) which caused ocrad to panic.

REPORTING BUGS

Report bugs to bug-ocrad@gnu.org
Ocrad home page: http://www.gnu.org/software/ocrad/ocrad.html
General help using GNU software: http://www.gnu.org/gethelp

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