CHAPTER Template Matching 5 5.1 INTRODUCTION In this chapter, we assume that each class is represented by a single pattern. A set of such reference patterns (or prototypes) is available and stored in a database. Given an unknown test pattern, template matching consists of searching the database for the reference pattern most "similar" to the given test pattern. This is equivalent to defining a matching cost that quantifies similarity between the test pattern and the reference patterns. Template-matching techniques are very common in string matching, speech recognition, alignment of molecular sequences, image retrieval, and so forth. They often come with different names depending on the application. For example, in speech recognition the term dynamic time warping is used, whereas