Biosignal pattern recognition and interpretation systems. 2. Methods for feature extraction and selection

Some feature extraction methods used in biomedical signal pattern recognition are presented. Particular attention is given to nontransformed signal characteristics, transformed signal characteristics, structural descriptors, graph descriptors, and feature selection methods. It is noted that the wide variety of techniques used for feature extraction presents two problems: which techniques should be used and how to select from among the features that each extraction technique generates. Selected features are best only by some standard; therefore, techniques for generation of features tend not to be very portable from one pattern processing problem to another. Production of salient features is the connecting link between prototypical and symbolic representations of a class. Often, thresholds govern the selection of features. Many techniques do not generate independent features; therefore, there is redundancy in the data, which potentially affects both efficiency and accuracy in pattern recognition.<>