Recognition Modules

The ImageGear Recognition API can load a number of recognition modules: which ones are present depends on its configuration. You can program which one should run in a given zone with the zone's ImGearRecZone.RecognitionModule Property. This allows your application to perform "multi-module" recognition on any image.

The ImGearRecRecognitionModule Enumeration lists the possible recognition modules:

PLUS3W omnifont module for machine-printed text (default)
PLUS2W omnifont module for machine-printed text
MTX omnifont module for machine-printed text
MOR multi-lingual omnifont module for machine-printed text
FRX multi-lingual omnifont module for machine-printed text
DOT module for 9-pin draft dot-matrix printouts
ASIAN module for Asian language text

Corresponding to the above list, the RecognitionModule Property of any zone should contain one of the following recognition module IDs: OMNIFONT_PLUS3W, OMNIFONT_PLUS2W, OMNIFONT_MTX, OMNIFONT_MOR, OMNIFONT_FRX, DOT, or one of the two special ones: NO_OCR and AUTO. The NO_OCR value means that no recognition will be done in the zone concerned.

AUTO means that the recognition engine will choose the module most likely to be appropriate. It does this first of all by consulting the filling method set for the zone.

The filling method describes the type of data expected in the zone, e.g., dot matrix printed text or machine generated text. A degree of auto-detection is available for the filling method, with the ImGearRecPage.DetectFillingMethod Method, which is useful when the precise filling method used on incoming documents may not be known in advance. It is the programmer's responsibility to specify a valid recognition module-filling method pair. Any incorrectly set zone will have no recognition result. Some filling methods can be linked successfully with one and only one recognition module. However, some recognition modules support more than one filling method, and some filling methods are accepted by more than one recognition module. For example, with mid-quality 9-pin dot-matrix text, either DOT or one of the omnifont modules could give better results. With mid-quality 24-pin dot-matrix text, try RM OMNIFONT_MOR with FM DOTMATRIX24 and OMNIFONT.

You can find detailed information on this and the different recognition modules in the Specifications for the Recognition Modules.

RM AUTO reads the filling method; if only one recognition module is suitable, it is used. When there is a choice, RM AUTO uses various checks (character set, image size, etc.) to select the best one. Thus, it protects against an invalid FM-RM pair.

If the recognition module is not present when it is needed, the Recognize Method throws an ImGearException with error code and value ImGearRecErrorCodes.REC_ENGINE_FAILURE / API_MODULEMISSING_ERR, and there will be no recognized data for the zone concerned. To avoid this risk, we recommend checking the presence and correct installation of the necessary recognition modules by examining the modules collection using the ImGearRecognition.Modules Property just after the Recognition API's initialization.