LEADTOOLS provides fast and highly accurate Optical Character Recognition SDK technology for .NET (C# & VB), C/C++, WinRT, iOS, macOS, Java, and web. The following sections describe this capability in more detail.
Automatic recognition module
NativeOcrZoneRecognitionModule.Auto
Specifies that the Engine will try to automatically select the most suitable recognition module for the zone. This is determined just before recognition, according to the zone's filling method and, if necessary, other settings, most typically the Character Set.
MTX OmniFont recognition module
NativeOcrZoneRecognitionModule.OmniFontMText
This recognition module recognizes machine-printed text; i.e. text from printed publications, laser or ink-jet printers and electric typewriters. Output from mechanical typewriters in good condition may also be acceptable. It should also be used for Letter or Near Letter Quality output from dot-matrix printers, and can also be used for Draft Quality.
Only images with the following resolution ranges are supported: 90-110, 160-240, 280-320, 400 and 600.
This module does not process images larger than 6600 pixels in either width or height. In other words, it can safely handle A3 size (11.69" x 16.54") (both portrait and landscape) images with 300 dpi resolution. At larger resolution the supported image size is smaller.
The module can handle a maximum of 64 zones defined on an image.
MOR multi-lingual OmniFont recognition module
NativeOcrZoneRecognitionModule.OmniFontMor
This module recognizes machine-printed text; i.e. text from printed publications, laser or ink-jet printers and electric typewriters. Output from mechanical typewriters in good condition may also be acceptable. It should also be used for Letter or Near Letter Quality (LQ, NLQ) output from dot-matrix printers. There are two ways of modifying incoming images to make them more suitable for the module:
This module can safely handle A3 size (11.69" x 16.54") (both portrait and landscape) images with 300 dpi resolution.
The module can handle a maximum of 500 zones defined on an image.
DOT Matrix (DOT 9-pin draft dot-matrix recognition module)
NativeOcrZoneRecognitionModule.DotMatrix
This module is designed for ONLY draft-quality 9-pin dot-matrix texts. For NLQ or LQ texts, the NativeOcrZoneRecognitionModule.OmniFontPlus2WayVoting, NativeOcrZoneRecognitionModule.OmniFontPlus3WayVoting, NativeOcrZoneRecognitionModule.OmniFontMText or NativeOcrZoneRecognitionModule.OmniFontMor modules give better results.
OMR optical mark recognition module
NativeOcrZoneRecognitionModule.Omr
LEADTOOLS OMR (Optical Mark Recognition) Module extends the functionality of LEADTOOLS SDKs by providing properties, methods, and events for easily incorporating fast, automated, and accurate optical mark recognition into your application. Optical Mark Recognition is used in surveys, polls, academic exams and official applications, to recognize the bubbles that the applicant fills in to indicate their selections. Supported marks include tick marks, X's, lines, checkmarks, and scribbles. Supported shapes (or frames) include boxes, circles and ellipses. For more information, refer to Using OMR in LEADTOOLS .NET OCR.
ICR hand-printed numeral recognition module
NativeOcrZoneRecognitionModule.IcrNumeral
This recognition module can be used for hand-printed numerals and four additional signs. If more hand-printed characters are to be recognized, use the NativeOcrZoneRecognitionModule.IcrCharacter recognition module.
ICR hand-printed recognition module
NativeOcrZoneRecognitionModule.IcrCharacter
This recognition module can be used for hand-printed characters. If only numerals need to be recognized, use the NativeOcrZoneRecognitionModule.IcrNumeral recognition module.
MAT matrix matching recognition module
NativeOcrZoneRecognitionModule.MatrixMatching
This module is designed to read certain groups of fixed-font characters specially designed for OCR or imaging applications, in which no two characters have similar shapes. Each character group has its own filling method. Application areas are in banking, check or waybill handling, product distribution and document validation, where high accuracy can be vital. It also handles some non-fixed print styles.
FRX multi-lingual OmniFont recognition module
NativeOcrZoneRecognitionModule.OmniFontFireWorx
This module recognizes machine-printed text; i.e. text from printed publications, laser or ink-jet printers and electric typewriters. Output from mechanical typewriters in good condition may also be acceptable. It should also be used for Letter or Near Letter Quality (LQ, NLQ) output from dot-matrix printers.
PLUS2WAY and PLUS3WAY Voting OmniFont recognition modules
NativeOcrZoneRecognitionModule.OmniFontPlus2WayVoting
NativeOcrZoneRecognitionModule.OmniFontPlus3WayVoting
These recognition modules recognize machine-printed text; i.e. text from printed publications, laser or ink-jet printers and electric typewriters. Output from mechanical typewriters in good condition may also be acceptable.
The PLUS2WAY and PLUS3WAY modules use voting technology to improve recognition results.
The PLUS2WAY voting module combines the results from the MOR and MTX modules.
The PLUS3WAY voting module combines the results from the MOR, MTX and FRX modules.
With either of these two voting modules, the accuracy is considerably better, but recognition may take significantly more time than any single module.
Note: The image handling algorithms for all modules of the Professional engine were designed to deal with practically unlimited image sizes: 32000 pixels in both directions.
Asian recognition module
NativeOcrZoneRecognitionModule.Asian
This module provides recognition services for four Asian languages with horizontal or vertical text direction; these languages are Japanese, Korean and Chinese - Traditional and Simplified. It can handle short embedded texts in English.
The Asian language handling differs somewhat from that for Western languages. Spell checking, editor display and verification are not available for Asian languages. Only one Asian language should be set for recognition and Western languages should not be set alongside an Asian language. However, the Asian OCR Engine can recognize short English texts embedded in Asian text, without English needing to be set. If embedded texts are in other Latin-alphabet languages, these similarly do not need to be set; however, accented characters may not always be handled correctly.
The following table shows the supported recognition modules for each OCR engine:
Recognition Module | Professional | Advantage | Arabic |
---|---|---|---|
Auto | Yes | Yes | Yes |
OmniFontMText | Yes | Yes | No |
OmniFontMor | Yes | Yes | No |
DotMatrix | Yes | Yes | No |
Omr | Yes | Yes | Yes |
IcrNumeral | Yes | Yes | No |
IcrCharacter | Yes | Yes | No |
MatrixMatching | Yes | Yes | No |
OmniFontFireWorx | Yes | Yes | No |
OmniFontPlus2WayVoting | Yes | Yes | No |
OmniFontPlus3WayVoting | Yes | Yes | No |
Asian | Yes | Yes | No |
The following table shows the text recognition module support for each of the 119 languages in the OCR Professional/Advantage engine:
Language | Omr | OmniFontMText | OmniFontFireWorx | OmniFontPlus2WayVoting | OmniFontPlus3WayVoting | DotMatrix | Icr |
---|---|---|---|---|---|---|---|
Afrikaans | Yes | No | Yes | Yes | Yes | Yes C | Yes |
Albanian | Yes | No | Yes | Yes | Yes | Yes C | Yes |
Aymara | Yes | No | Yes | Yes | Yes | Yes | Yes |
Basque | Yes | No | Yes | Yes | Yes | No | Yes |
Bemba | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Blackfoot | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Brazilian B | Yes B | Yes | Yes | Yes | Yes | Yes | Yes |
Breton | Yes | No | Yes | Yes | Yes | Yes C | Yes |
Bugotu | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Bulgarian | Yes | No | Yes | Yes | Yes | No | No |
Byelorussia | Yes | No | Yes | Yes | Yes | No | No |
Catalan | Yes | No | Yes | Yes | Yes | Yes C | Yes |
Chamorro | Yes | No | No | Yes | Yes | Yes | Yes |
Chechen | Yes | No | No | Yes | Yes | No | No |
Corsican | Yes | No | No | Yes | Yes | Yes | Yes |
Croatian | Yes | No | Yes | Yes | Yes | No | Yes |
Crow | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Czech | Yes | No | Yes | Yes | Yes | No | Yes |
Danish | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
Dutch | Yes | Yes | Yes | Yes | Yes | Yes C | Yes |
English | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
Eskimo (Inuit) | Yes | No | Yes | Yes | Yes | No | Yes |
Esperanto | Yes | No | No | Yes | Yes | No | No |
Estonian | Yes | No | Yes | Yes | Yes | Yes | Yes |
Faroese | Yes | No | Yes | Yes | Yes | No | No |
Fijian | Yes | No | No | Yes | Yes | No | Yes |
Finnish | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
French | Yes | Yes | Yes | Yes | Yes | Yes C | Yes |
Frisian | Yes | No | Yes | Yes | Yes | Yes C | Yes |
Friulian | Yes | No | Yes | Yes | Yes | Yes C | Yes |
Gaelic (Irish) | Yes | No | Yes | Yes | Yes | Yes | Yes |
Gaelic (Scottish) | Yes | No | Yes | Yes | Yes | Yes C | Yes |
Galician | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
Ganda | Yes | No | No | Yes | Yes | No | Yes |
German | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
Greek | Yes | No | Yes | Yes | Yes | Yes | No |
Guarani | Yes | No | No | Yes | Yes | Yes C | Yes |
Hani * | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Hawaiian | Yes | Yes EN | Yes | Yes | Yes | Yes | Yes |
Hungarian | Yes | No | Yes | Yes | Yes | Yes | Yes |
Icelandic | Yes | No | Yes | Yes | Yes | No | No |
Ido | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Indonesian | Yes | Yes EN | Yes | Yes | Yes | Yes | Yes |
Interlingua | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Italian | Yes | Yes | Yes | Yes | Yes | Yes C | Yes |
Kabardian | Yes | No | No | Yes | Yes | No | No |
Kasub | Yes | No | No | Yes | Yes | No | Yes |
Kawa * | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Kikuyu | Yes | No | No | Yes | Yes | No | No |
Kongo | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Kpelle | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Kurdish * | Yes | No | Yes | Yes | Yes | No | Yes |
Latin L | Yes | Yes L | Yes | Yes | Yes | Yes L | Yes |
Latvian | Yes | No | Yes | Yes | Yes | No | Yes |
Lithuanian | Yes | No | Yes | Yes | Yes | No | Yes |
Luba | Yes | No | No | Yes | Yes | No | Yes |
Luxembourgian | Yes | No | No | Yes | Yes | Yes C | Yes |
Macedonian | Yes | No | Yes | Yes | Yes | No | No |
Malagasy | Yes | Yes EN/M | No | Yes | Yes | Yes C | Yes |
Malay | Yes | No | Yes | Yes | Yes | No | Yes |
Malinke | Yes | No | No | Yes | Yes | Yes C | Yes |
Maltese | Yes | No | No | Yes | Yes | No | No |
Maori | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Mayan | Yes | No | No | Yes | Yes | Yes | Yes |
Miao * | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Minankabaw | Yes | No | No | Yes | Yes | No | Yes |
Mohawk | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Moldavian | Yes | No | No | Yes | Yes | No | No |
Nahuatl | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Norwegian | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
Nyanja | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Occidental | Yes | No | No | Yes | Yes | Yes | Yes |
Ojibway | Yes | No | No | Yes | Yes | No | Yes |
Papiamento | Yes | No | No | Yes | Yes | Yes | Yes |
Pigin English | Yes | Yes EN | Yes | Yes | Yes | Yes | Yes |
Polish | Yes | No | Yes | Yes | Yes | No | Yes |
Portuguese | Yes | Yes | Yes | Yes | Yes | Yes C | Yes |
Provençal | Yes | No | No | Yes | Yes | Yes C | Yes |
Quechua | Yes | No | No | Yes | Yes | Yes | Yes |
Rhaetic | Yes | No | No | Yes | Yes | Yes C | Yes |
Romanian | Yes | No | Yes | Yes | Yes | No | No |
Romany | Yes | No | No | Yes | Yes | No | Yes |
Ruanda | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Rundi | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Russian | Yes | No | Yes | Yes | Yes | No | No |
Sami | Yes | No | No | Yes | Yes | No | Yes |
Sami, Lule | Yes | No | No | Yes | Yes | No | Yes |
Sami, Northern | Yes | No | No | Yes | Yes | No | Yes |
Sami, Southern | Yes | No | No | Yes | Yes | No | Yes |
Samoan | Yes | No | No | Yes | Yes | Yes C | Yes |
Sardinian | Yes | No | No | Yes | Yes | Yes C | Yes |
Serbian | Yes | No | Yes | Yes | Yes | No | No |
Serbian, Latinic | Yes | No | Yes | Yes | Yes | No | Yes |
Shona S | Yes | Yes S | No | Yes | Yes | Yes S | Yes |
Sioux | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Slovak | Yes | No | Yes | Yes | Yes | No | Yes |
Slovenian | Yes | No | Yes | Yes | Yes | No | Yes |
Somali | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Sorbian (Wend) | Yes | No | Yes | Yes | Yes | No | Yes |
Sotho | Yes | No | No | Yes | Yes | Yes | Yes |
Spanish | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
Sundanese SN | Yes | No | No | Yes | Yes | Yes SN | Yes SN |
Swahili | Yes | Yes EN | Yes | Yes | Yes | Yes | Yes |
Swazi | Yes | No | No | Yes | Yes | No | Yes |
Swedish | Yes | Ye | Yes | Yes | Yes | Yes | Yes |
Tagalog | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Tahitian | Yes | No | Yes | Yes | Yes | Yes C | Yes |
Tinpo | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Tongan | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Tswana (Chuana) | Yes | No | No | Yes | Yes | Yes C | Yes |
Tun * | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Turkish | Yes | No | Yes | Yes | Yes | No | Yes T |
Ukrainian | Yes | No | Yes | Yes | Yes | No | No |
Visayan | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Welsh | Yes | No | Yes | Yes | Yes | Yes W | Yes W |
Wolof | Yes | No | No | Yes | Yes | Yes C | Yes |
Xhosa | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Zapotec | Yes | Yes EN | No | Yes | Yes | Yes | Yes |
Zulu | Yes | No | Yes | Yes | Yes | No | Yes |
* = This language can be handled only if it is written in the Latin alphabet.
B = Brazilian has a separate dictionary from Portuguese in the OmniFontMText and OmniFontFireWorx modules. Other modules treat Brazilian as Portuguese. Brazilian is available for language marking in the output document.
L = Latin is usually written without accented letters, but sometimes breves or macrons are placed over vowels. In these cases, the indicated modules do not provide support.
M = Some dialects of Malagasy are written without accents. In these cases, OmniFontMText provides support.
S = Shona may be written without accents, but sometimes uses acutes and graves on vowels. In these cases the indicated modules do not provide full support.
SN = Sundanese uses only one accented letter; sometimes this is E-breve, sometimes E-acute. The indicated modules support E-acute but not E-breve.
W = Welsh contains two rarely used characters: W-circumflex and Y-circumflex. These modules can handle Welsh with the exception of these two characters.
The twelve selectable languages are those with Yes with no added footnote letter. For these languages this module uses its own language dictionaries.
EN = Languages denoted are thought to contain no accented letters. To read them, select English and disable spell checking from a main dictionary.
C = Not all uppercase letters are supported. See the module specification for a precise listing. This is probably not a serious restriction, since many 9-pin dot-matrix printers cannot print all the accented uppercase characters.
T = The module cannot handle the lowercase dotless-i.
Reference
Getting Started (Guide to Example Programs)
Programming with LEADTOOLS .NET OCR
Creating an OCR Engine Instance
Starting and Shutting Down the OCR Engine
Multi-Threading with LEADTOOLS OCR
OCR Spell Language Dictionaries
Using OMR in LEADTOOLS .NET OCR
OCR Languages and Spell Checking
OCR Tutorial - Working with Pages
OCR Tutorial - Recognizing Pages
OCR Tutorial - Adding and Painting Zones