Pattern Recognition, 4th Edition

11.1. Introduction

All the previous chapters were concerned with supervised classification. In the current and following chapters, we turn to the unsupervised case, where class labeling of the training patterns is not available. Thus, our major concern now is to “reveal” the organization of patterns into “sensible” clusters (groups), which will allow us to discover similarities and differences among patterns and to derive useful conclusions about them. This idea is met in many fields, such as the life sciences (biology, zoology), medical sciences (psychiatry, pathology), social sciences (sociology, archaeology), earth sciences (geography, geology), and engineering [Ande 73]. Clustering may be found under different names in different contexts, ...