Data Clustering: A Review

Clustering is the unsupervised classi cation of patterns (observations, data items, or feature vectors) into groups (clusters). The clustering problem has been addressed in many contexts and by researchers in many disciplines � this re ects its broad appeal and usefulness as one of the steps in exploratory data analysis. However, clustering is a di cult problem combinatorially and di erences in assumptions and contexts in di erent communities has made the transfer of useful generic concepts and methodologies slow to occur. This paper presents an overview of pattern clustering methods from a statistical pattern recognition perspective, with a goal of providing useful advice and references to fundamental concepts accessible to the broad community of clustering practitioners. We present a taxonomy of clustering techniques and identify cross-cutting themes and recent advances. We also describe some important applications of clustering algorithms such as image segmentation, object recognition, and information retrieval