This book presents a fuzzy approach to the problems of pattern recognition, machine learning, and, especially, speech recognition.

The first three chapters are devoted to the mathematical framework of the theory of fuzzy sets, basic operations related to it, and the development of classification algorithms, mainly conventional algorithms known as “fuzzy clustering techniques.” Cluster validity is also overviewed.

Chapter 4 deals with different image processing techniques using fuzzy methods. The image is considered as an array of fuzzy singletons, each with a value-of-membership function denoting the degree of having given brightness.

Chapter 5 provides the methodologies for feature selection and applies it to a speech recognition problem in a consonant-vowel-consonant context from a major Indian language vocabulary uttered by three speakers. For the vowel-sound recognition, the first three formant frequencies at the steady state are used. For the plosive consonants, the difference of the initial and final values of the first and second formants, the duration, and the rates of transition are considered as the feature set. This chapter also covers shape analysis, image description, and primitive extraction.

Chapter 6, Speech Recognition, is the central part of this book. It presents a theoretical development and a practical application to fuzzy algorithms in speech-sound recognition and speaker identification problems, as developed by the authors in the 1970s. Despite the fact that it illustrates perfectly the techniques proposed by the authors, it is clearly a small part of the procedures to be involved in the phonemic labeling of speech, which is the basic tool used for big vocabularies recognition and continuous acoustic speech. Fuzzy mathematics is also applied to speaker identification with the use of a vowels recognition procedure.

Chapter 7 discusses some of the training and learning fuzzy algorithms for designing self-adaptive systems. Chapter 8 deals with fuzzy grammar and syntactic recognition, which are applied to the hand-written character recognition and the identification of skeletal maturity from X-ray images.

I enjoyed reading the book. I would especially like to recommend it as a reference for post-graduate-level courses in the speech recognition field. I am sure a lot of researchers in that specific field would benefit from reading it and would perhaps discover, or be reconciled with, the fuzzy approach.