8. A method as recited in claim 7, including the further step of comparing results of said counting step.
8. A method as recited in claim 7, including the further step of comparing results of said counting step. 9. A method as recited in claim 8, including the further step of determining whether or not a distance of a parameter of a feature vector from a mean value of a parameter of a codeword is greater than a distance corresponding to a variance of a corresponding parameter of said codeword for each of a plurality of feature vectors, and detecting a rate of occurrence of a result of said determining step.