Recognition Modules and Filters

Narrowing the Character Set has two effects:

It influences the automatic recognition module selection
It may increase accuracy

The filtering system allows the Language environment to be narrowed by enabling only certain character classes, and also by enabling individual characters. A filter is built up from filter elements, as detailed under the enumIGRecChrFilter description.

Each filter element name tells which character class is enabled; e.g., IG_REC_FILTER_ALL means no filtering. Not all recognition modules interpret all filter elements. Precise information appears in the sub-heading for each module.

Applying a filter may not always enable the same number of characters; e.g., IG_REC_FILTER_MISCELLANEOUS can enable only those miscellaneous characters supported by the recognition module assigned to the zone.