How Postal Address Readers Are Made Adaptive

In the following chapter we describe how a postal address reader is made adaptive. A postal address reader is a huge application, so we concentrate on technologies used to adapt it to a few important tasks. In particular, we describe adaptation strategies for the detectors and classifiers of regions of interest (ROI), for the classifiers for single character recognition, for a hidden Markov recogniser for hand written words and for the address dictionary of the reader. The described techniques have been deployed in all postal address reading applications, including parcel, flat, letter and in-house mail sorting.