NAME¶
gocr - command line text recognition tool
SYNOPSIS¶
gocr [
OPTION] [
-i]
pnm-file
DESCRIPTION¶
gocr is an optical character recognition program that can be used from the
command line. It takes input in PNM, PGM, PBM, PPM, or PCX format, and writes
recognized text to
stdout. If the
pnm file is a single
dash, PNM data is read from
stdin. If gzip, bzip2 and netpbm-progs are
installed and your system supports
popen(3) also pnm.gz, pnm.bz2, png, jpg,
jpeg, tiff, gif, bmp, ps (only single pages) and eps are supported as input
files (not as input stream), where pnm can be replaced by one of ppm, pgm and
pbm.
OPTIONS¶
- -h
- show usage information
- -i file
- read input from file (or stdin if file
is a single dash)
- -o file
- send output to file instead of stdout
- -e file
- send errors to file instead of stderr or to
stdout if file is a dash
- -x file
- progress output to file ( file can be a file
name, a fifo name or a file descriptor 1...255), this is useful for GUI
developpers to show the OCR progress, the file descriptor argument is only
available, if compiled with __USE_POSIX defined
- -p path
- database path, a final slash must be included, default is
./db/, this path will be populated with images of learned characters
- -f format
- output format of the recognized text (ISO8859_1 TeX
HTML XML UTF8 ASCII), XML will also output position and probability
data
- -l level
- set grey level to level (0<160<=255, default:
0 for autodetect), darker pixels belong to characters, brighter pixels are
interpreted as background of the input image
- -d size
- set dust size in pixels (clusters smaller than this are
removed), 0 means no clusters are removed, the default is -1 for auto
detection
- -s num
- set spacewidth between words in units of dots (default: 0
for autodetect), wider widths are interpreted as word spaces, smaller as
character spaces
- -v verbosity
- be verbose to stderr; verbosity is a bitfield
- -c string
- only verbose output of characters from string to
stderr, more output is generated for all characters within the string, the
underscore stands for unknown chars, this function is usefull to limit
debug information to the necessary one
- -C string
- only recognise characters from string, this is a
filter function in cases where the interest is only to a part of the
character alphabet, you can use 0-9 or a-z to specify ranges, use -- to
detect the minus sign
- -a certainty
- set value for certainty of recognition (0..100; default:
95), characters with a higher certainty are accepted, characters with a
lower certainty are treated as unknown (not recognized); set higher
values, if you want to have only more certain recognized characters
- -u string
- output this string for every unrecognized character
(default is "_")
- -m mode
- set oprational mode; mode is a bitfield (default: 0)
- -n bool
- if bool is non-zero, only recognise numbers (this is
now obsolete, use -C "0123456789")
The verbosity is specified as a bitfield:
- 1
- print more info
- 2
- list shapes of boxes (see -c) to stderr
- 4
- list pattern of boxes (see -c) to stderr
- 8
- print pattern after recognition for debugging
- 16
- print debug information about recognition of lines to
stderr
- 32
- create outXX.png with boxes and lines marked on each
general OCR-step
The operation modes are:
- 2
- use database to recognize characters which are not
recognized by other algorithms, (early development)
- 4
- switching on layout analysis or zoning (development)
- 8
- don't compare unrecognized characters to recognized
one
- 16
- don't try to divide overlapping characters to two or three
single characters
- 32
- don't do context correction
- 64
- character packing, before recognition starts, similar
characters are searched and only one of this characters will be send to
the recognition engine (development)
- 130
- extend database, prompts user for unidentified characters
and extends the database with users answer (128+2, early development)
- 256
- switch off the recognition engine (makes sense together
with -m 2)
AUTHOR¶
Joerg Schulenburg (see
http://jocr.sourceforge.net/ for EMAIL)
First version of man page by Tim Waugh <twaugh@redhat.com>
This man page documents
gocr, version 0.41.
REPORTING BUGS¶
Report bugs to Joerg Schulenburg
SEE ALSO¶
More details can be found at /usr/share/doc/gocr-
X.XX/gocr.html. Also
read /usr/share/doc/gocr-
X.XX/README to learn, how to improve results.
EXAMPLES¶
- gocr -v 33 text1.pbm
- output verbose information, out30.png is created to see
details of recognition process
- gocr -v 7 -c _YV text1.pbm
- verbose output for unknown chars and chars Y and V
- djpeg -pnm -gray text.jpg | gocr -
- convert a jpeg file to pnm format and input via pipe
