The basic principles of HMM-based recognition were outlined in the previous chapter and a number of the key HTK tools have already been mentioned. This chapter describes the software architecture of a HTK tool. It then gives a brief outline of all the HTK tools and the way that they are used together to construct and test HMM-based recognisers. For the benefit of existing HTK users, the major changes in HTK Version 2.0 are listed. The following chapter will then illustrate the use of the HTK toolkit by working through a practical example of building a simple continuous speech recognition system.
