The primary goal of pattern recognition is supervised or unsupervised class
ification. Among the various frameworks in which pattern recognition has be
en traditionally formulated, the statistical approach has been most intensi
vely studied and used in practice. More recently, neural network techniques
and methods imported from statistical learning theory have been receiving
increasing attention. The design of a recognition system requires careful a
ttention to the following issues: definition of pattern classes, sensing en
vironment, pattern representation, feature extraction and selection, cluste
r analysis, classifier design and learning. selection of training and lest
samples, and performance evaluation. In spite of almost 50 years of researc
h and development in this field, the general problem of recognizing complex
patterns with arbitrary orientation, location, and scale remains unsolved.
New and emerging applications, such as data mining. web searching, retriev
al of multimedia data, face recognition, and cursive handwriting recognitio
n, require robust and efficient pattern recognition techniques. The objecti
ve of this review paper is to summarize and compare some of the well-known
methods used in various stages of a pattern recognition system and identify
research topics and applications which are at the forefront of this exciti
ng and challenging field.