Application of the Karhunen-Loeve transform in pattern recognition pro
blems necessitates knowledge of the mean vectors for the training sets
of different classes for construction of the respective covariance ma
trices. This modality poses problems for recognizing an unknown signal
in a multi-class environment and for its on-line implementation. This
is because a priori it is unknown which mean vector of the several cl
asses is to be subtracted from an unknown input signal. To remove this
difficulty a global mean approach has been proposed. The proposed met
hod has been applied to synthetic and experimentally observed acoustic
signals successfully and its performance with respect to pattern reco
gnition and data compression has been compared with the conventional m
ethod.