Structural pattern recognition

Abstract

This book is a revised edition of Duda and Hart's classic text on Pattern Classification which was originally published in 1973. In fact, the 1973 edition of the book played a pivotal role in introducing me (and countless researchers of my generation) to the field of pattern classification. Needless to say, I was looking forward to the release of the revised edition. Unfortunately, I was extremely disappointed with the new edition. I had expected much more from the masters: Duda and Hart! My reasons for disappointment with this book are as follows: Given the 27 years that have elapsed since the publication of the first edition of the book, and the immense progress that has taken place in pattern recognition, machine learning, computational learning theory, grammar inference, statistical inference, algorithmic information theory, and related areas, the revisions and additions in the 2000 edition are essentially of a patchwork nature. In my opinion, they do not reflect the current understanding of the topic of pattern classification. A disproportionate number of pages are devoted to topics like density estimation despite the fact that it has been well established in recent years, through the work of Vapnik and others, that when working with limited data, trying to solve the problem of pattern classification through density estimation (which turns out to be, in a well-defined sense of the term, a much harder problem than pattern classification) is rather futile. When modern techniques for learning pattern classifiers from limited data sets (e.g., support vector classifiers) are touched on in the book, the treatment is disappointingly superficial and in some cases, misleading. There is virtually no discussion of problems of learning from large high dimensional data sets, incremental refinement of classifiers, learning from sequential data, distributed algorithms, etc. The treatment of non-numeric pattern recognition techniques (e.g., automata, languages, etc.) is extremely superficial. There is almost no discussion of essential aspects such as preprocessing and feature extraction techniques for dealing with variable length, semistructured, or unstructured patterns. There is very little contact made with a large body of pattern classification algorithms, results, and approaches developed by the machine learning community, some exceptions. There is little discussion of the extremely important topic of computational complexity and data requirements of learning algorithms. On the positive side, the discussion of most topics that were originally covered in the 1973 edition has been further refined and in many cases, made more accessible through the addition of illustrative examples and diagrams. Topics such as Bayesian networks receive an intutive and accessible treatment. It was good to see a treatment of techniques for combining classifiers (although it is placed misleadingly in a chapter titled "Algorithm-Independent Machine Learning" which has an organization that is reminescent of a "kitchen sink"). The exercises at the end of each chapter seems useful. Perhaps it is too difficult for any individual or a small group of individuals to write a textbook that reflects the state of the art in pattern recognition. Perhaps my expectations of Duda and Hart (based largely on the extraordinary job that did on the 1973 edition of their book) were too high to have a reasonable chance of being met by the 2000 edition. Perhaps I have come to expect more out of graduate level textbooks after having worked as a researcher and an educator in this field for over a decade at a major university. In short, the book fell significantly short of my expectation.