1TESSERACT(1) TESSERACT(1)
2
6 tesseract - command-line OCR engine
7
9 tesseract imagename|stdin outputbase|stdout [options...]
10 [configfile...]
11
13 tesseract(1) is a commercial quality OCR engine originally developed at
14 HP between 1985 and 1995. In 1995, this engine was among the top 3
15 evaluated by UNLV. It was open-sourced by HP and UNLV in 2005, and has
16 been developed at Google since then.
17
19 imagename
20 The name of the input image. Most image file formats (anything
21 readable by Leptonica) are supported.
22 stdin
24 Instruction to read data from standard input
25 outputbase
27 The basename of the output file (to which the appropriate extension
28 will be appended). By default the output will be named outbase.txt.
29 stdout
31 Instruction to sent output data to standard output
32
34 --tessdata-dir /path
35 Specify the location of tessdata path
36 --user-words /path/to/file
38 Specify the location of user words file
39 --user-patterns /path/to/file specify
41 The location of user patterns file
42 -c configvar=value
44 Set value for control parameter. Multiple -c arguments are allowed.
45 -l lang
47 The language to use. If none is specified, English is assumed.
48 Multiple languages may be specified, separated by plus characters.
49 Tesseract uses 3-character ISO 639-2 language codes. (See
50 LANGUAGES)
51 --psm N
53 Set Tesseract to only run a subset of layout analysis and assume a
54 certain form of image. The options for N are:
55 0 = Orientation and script detection (OSD) only.
57 1 = Automatic page segmentation with OSD.
58 2 = Automatic page segmentation, but no OSD, or OCR.
59 3 = Fully automatic page segmentation, but no OSD. (Default)
60 4 = Assume a single column of text of variable sizes.
61 5 = Assume a single uniform block of vertically aligned text.
62 6 = Assume a single uniform block of text.
63 7 = Treat the image as a single text line.
64 8 = Treat the image as a single word.
65 9 = Treat the image as a single word in a circle.
66 10 = Treat the image as a single character.
67 configfile
69 The name of a config to use. A config is a plaintext file which
70 contains a list of variables and their values, one per line, with a
71 space separating variable from value. Interesting config files
72 include:
73 · hocr - Output in hOCR format instead of as a text file.
76 · pdf - Output in pdf instead of a text file.
78 Nota Bene: The options -l lang and --psm N must occur before any
80 configfile.
81
83 -v
84 Returns the current version of the tesseract(1) executable.
85 --list-langs
87 list available languages for tesseract engine. Can be used with
88 --tessdata-dir.
89 --print-parameters
91 print tesseract parameters to the stdout.
92
94 There are currently language packs available for the following
95 languages (in https://github.com/tesseract-ocr/tessdata):
96 afr (Afrikaans) amh (Amharic) ara (Arabic) asm (Assamese) aze
98 (Azerbaijani) aze_cyrl (Azerbaijani - Cyrilic) bel (Belarusian) ben
99 (Bengali) bod (Tibetan) bos (Bosnian) bul (Bulgarian) cat (Catalan;
100 Valencian) ceb (Cebuano) ces (Czech) chi_sim (Chinese - Simplified)
101 chi_tra (Chinese - Traditional) chr (Cherokee) cym (Welsh) dan (Danish)
102 dan_frak (Danish - Fraktur) deu (German) deu_frak (German - Fraktur)
103 dzo (Dzongkha) ell (Greek, Modern (1453-)) eng (English) enm (English,
104 Middle (1100-1500)) epo (Esperanto) equ (Math / equation detection
105 module) est (Estonian) eus (Basque) fas (Persian) fin (Finnish) fra
106 (French) frk (Frankish) frm (French, Middle (ca.1400-1600)) gle (Irish)
107 glg (Galician) grc (Greek, Ancient (to 1453)) guj (Gujarati) hat
108 (Haitian; Haitian Creole) heb (Hebrew) hin (Hindi) hrv (Croatian) hun
109 (Hungarian) iku (Inuktitut) ind (Indonesian) isl (Icelandic) ita
110 (Italian) ita_old (Italian - Old) jav (Javanese) jpn (Japanese) kan
111 (Kannada) kat (Georgian) kat_old (Georgian - Old) kaz (Kazakh) khm
112 (Central Khmer) kir (Kirghiz; Kyrgyz) kor (Korean) kur (Kurdish) lao
113 (Lao) lat (Latin) lav (Latvian) lit (Lithuanian) mal (Malayalam) mar
114 (Marathi) mkd (Macedonian) mlt (Maltese) msa (Malay) mya (Burmese) nep
115 (Nepali) nld (Dutch; Flemish) nor (Norwegian) ori (Oriya) osd
116 (Orientation and script detection module) pan (Panjabi; Punjabi) pol
117 (Polish) por (Portuguese) pus (Pushto; Pashto) ron (Romanian;
118 Moldavian; Moldovan) rus (Russian) san (Sanskrit) sin (Sinhala;
119 Sinhalese) slk (Slovak) slk_frak (Slovak - Fraktur) slv (Slovenian) spa
120 (Spanish; Castilian) spa_old (Spanish; Castilian - Old) sqi (Albanian)
121 srp (Serbian) srp_latn (Serbian - Latin) swa (Swahili) swe (Swedish)
122 syr (Syriac) tam (Tamil) tel (Telugu) tgk (Tajik) tgl (Tagalog) tha
123 (Thai) tir (Tigrinya) tur (Turkish) uig (Uighur; Uyghur) ukr
124 (Ukrainian) urd (Urdu) uzb (Uzbek) uzb_cyrl (Uzbek - Cyrilic) vie
125 (Vietnamese) yid (Yiddish)
126 To use a non-standard language pack named foo.traineddata, set the
128 TESSDATA_PREFIX environment variable so the file can be found at
129 TESSDATA_PREFIX/tessdata/foo.traineddata and give Tesseract the
130 argument -l foo.
131
133 Tesseract config files consist of lines with variable-value pairs
134 (space separated). The variables are documented as flags in the source
135 code like the following one in tesseractclass.h:
136 STRING_VAR_H(tessedit_char_blacklist, "", "Blacklist of chars not to
138 recognize");
139 These variables may enable or disable various features of the engine,
141 and may cause it to load (or not load) various data. For instance,
142 let’s suppose you want to OCR in English, but suppress the normal
143 dictionary and load an alternative word list and an alternative list of
144 patterns — these two files are the most commonly used extra data files.
145 If your language pack is in /path/to/eng.traineddata and the hocr
147 config is in /path/to/configs/hocr then create three new files:
148 /path/to/eng.user-words:
150 the
152 quick
153 brown
154 fox
155 jumped
156 /path/to/eng.user-patterns:
158 1-\d\d\d-GOOG-411
160 www.\n\\\*.com
161 /path/to/configs/bazaar:
163 load_system_dawg F
165 load_freq_dawg F
166 user_words_suffix user-words
167 user_patterns_suffix user-patterns
168 Now, if you pass the word bazaar as a trailing command line parameter
170 to Tesseract, Tesseract will not bother loading the system dictionary
171 nor the dictionary of frequent words and will load and use the
172 eng.user-words and eng.user-patterns files you provided. The former is
173 a simple word list, one per line. The format of the latter is
174 documented in dict/trie.h on read_pattern_list().
175
177 The engine was developed at Hewlett Packard Laboratories Bristol and at
178 Hewlett Packard Co, Greeley Colorado between 1985 and 1994, with some
179 more changes made in 1996 to port to Windows, and some C++izing in
180 1998. A lot of the code was written in C, and then some more was
181 written in C++. The C\++ code makes heavy use of a list system using
182 macros. This predates stl, was portable before stl, and is more
183 efficient than stl lists, but has the big negative that if you do get a
184 segmentation violation, it is hard to debug.
185 Version 2.00 brought Unicode (UTF-8) support, six languages, and the
187 ability to train Tesseract.
188 Tesseract was included in UNLV’s Fourth Annual Test of OCR Accuracy.
190 See https://github.com/tesseract-ocr/docs/blob/master/AT-1995.pdf. With
191 Tesseract 2.00, scripts are now included to allow anyone to reproduce
192 some of these tests. See
193 https://github.com/tesseract-ocr/tesseract/wiki/TestingTesseract for
194 more details.
195 Tesseract 3.00 adds a number of new languages, including Chinese,
197 Japanese, and Korean. It also introduces a new, single-file based
198 system of managing language data.
199 Tesseract 3.02 adds BiDirectional text support, the ability to
201 recognize multiple languages in a single image, and improved layout
202 analysis.
203 For further details, see the file ReleaseNotes included with the
205 distribution.
206
208 Main web site: https://github.com/tesseract-ocr Information on
209 training:
210 https://github.com/tesseract-ocr/tesseract/wiki/TrainingTesseract
211
213 ambiguous_words(1), cntraining(1), combine_tessdata(1),
214 dawg2wordlist(1), shape_training(1), mftraining(1), unicharambigs(5),
215 unicharset(5), unicharset_extractor(1), wordlist2dawg(1)
216
218 Tesseract development was led at Hewlett-Packard and Google by Ray
219 Smith. The development team has included:
220 Ahmad Abdulkader, Chris Newton, Dan Johnson, Dar-Shyang Lee, David
222 Eger, Eric Wiseblatt, Faisal Shafait, Hiroshi Takenaka, Joe Liu, Joern
223 Wanke, Mark Seaman, Mickey Namiki, Nicholas Beato, Oded Fuhrmann, Phil
224 Cheatle, Pingping Xiu, Pong Eksombatchai (Chantat), Ranjith
225 Unnikrishnan, Raquel Romano, Ray Smith, Rika Antonova, Robert Moss,
226 Samuel Charron, Sheelagh Lloyd, Shobhit Saxena, and Thomas Kielbus.
227
229 Licensed under the Apache License, Version 2.0
230 06/28/2015 TESSERACT(1)