Filtering the set of characters

Limiting the set of characters to the ones expected in the zone improves handprint recognition accuracy considerably. Use the filter bits (FILTER_PLUS_*) and an extended filter setting function (kRecSetFilterPlusEx) to specify different sets of characters for each hand-printed zone.

By default, the CSDK API expects the more general forms and features of handwriting and does not assume rare, more unique handwriting styles. This limits the set of character shapes but improves recognition accuracy effectively. However, the engine can recognize many different forms of the same character, even rare outlines. Set the Kernel.OcrMgr.Handprint.FullCharacterSet setting to TRUE to instruct the engine to look for the rare forms, though this may reduce accuracy.