OCR(1) (cetus,hydra,coma) OCR(1)
NAME
ocr - optical character recognition
SYNOPSIS
ocr [ option ... ] [ file ]
DESCRIPTION
Ocr reads a black-and-white image of a page from file, and
writes ASCII to the standard output. If no file is speci-
fied, it reads from the standard input.
The input is a picfile(5) image of one column of machine-
printed text, normally scanned in by cscan(1). Fonts, sizes,
and line-spacings may vary within the column, but each line
should have a constant text size and baseline. Lines should
be parallel and roughly horizontal.
In the output, white space approximates the original page
layout. Words that spell(1) are preferred, and hyphenations
across lines are recombined.
The options are:
-as The alphabet is the union of symbol sets selected by
characters in string s, from among:
A ABCDEFGHIJKLMNOPQRSTUVWXYZ
a abcdefghijklmnopqrstuvwxyz
0 0123456789
. .,-:;*'"?!/&$()[]#@% (basic punctuation)
^ ^~`\|{}_ (extended punct'n)
+ +-*/<>=.Ee[] (numerical punct'n)
s \(sc\(dg\(dd\(ct\(bu\(co ... (selected non-ASCII)
l fi fl ff ffi ffl ae oe ... (ligatures, digraphs)
g \(*a\(*b\(*g\(*d\(*e\(*z ... (Greek lower case)
G AB\(*G\(*DEZ ... (Greek upper case)
The default is -aAa0.+^, the full printable-ASCII
set, which may be abbreviated as -ap. Thus, -apslgG
selects all of the above.
-c Find columns in complex nested layouts using greedy
white covers algorithm.
-ml[,r]
Trim the left and right margins of the image by l and
r inches, respectively, before looking for columns.
If r is omitted, it is assumed to equal l.
-nn Find the n largest columns by analysis of a single
OCR(1) (cetus,hydra,coma) OCR(1)
vertical projection. Each column should be
compactly-printed and separated from the others by at
least 2 ems of horizontal white space.
-pn,m Point sizes lie in the range [ n, m ]; other sizes
are discarded. The default is -p6,24.
-s Defeat spelling check (but continue to favor numeric
strings and good punctuation).
-t Write troff(1) format. Each column is shown on a
separate page, lines at their original height, words
at their original horizontal location, and characters
roughly original size in Times roman. Hyphenated
words are not recombined.
-u Unspellable words are prefixed with `?' or, if -t is
specified, printed boldface.
-ww Find the largest column of width w inches, within a
single vertical projection.
Fonts
Trained on over 100 Latin-alphabet book fonts in various
italic, bold, etc styles. Only one font of Greek, without
diacriticals. Also Swedish and Tibetan, on request.
SEE ALSO
bcp(1), cscan(1), font(6), picfile(5), spell(1), troff(1)
BUGS
For best results, use images of high-contrast, cleanly-
printed original documents digitized at a resolution of 400
pixels/inch or higher. It may help to restrict the alphabet
and sizes to what's there.