A two-stage HMM-based system for recognizing handwritten numeral strings

The authors propose a handwritten numeral string recognition method composed of two HMM-based stages. The first stage uses an implicit segmentation strategy based on string contextual information to provide multiple segmentation-recognition paths. These paths are verified and re-ranked by using a verification stage based on a digit classifier. It allows the use of two sets of features and numeral models: one taking into account both segmentation and recognition aspects in an implicit segmentation based strategy, and another considering just recognition aspects of isolated digits. The two system stages are shown to be complementary in the sense that the verification stage is shown to be a promising idea to deal with the loss in terms of recognition performance brought about by the necessary tradeoff between segmentation and recognition carried out in the first system stage