Patent ID: 6728645
Filing Date: 2004-04-27
Classification: G01H

Abstract:
A method for an automatic classification of a target among a plurality of objects according to the target vibration in the audio frequency range, the method comprises the stages of:(a) providing vibration signals from a first object and from a second object; (b) processing said vibration signals of both said first and said second object into respective vibration spectra by a wavelet packet transform; (c) identifying at least one most discriminating frequency band in which a difference between said vibration spectrum of said first object and said vibration spectrum of said second object are mostly pronounced; (d) choosing a spectral resolution for which a discrimination between said vibration spectrum of said first object and said vibration spectrum of said second object cannot be further improved; (e) attributing immutable features to each of said vibration spectrum of said first and said second object within said most discriminating frequency band at said spectral resolution; (f) acquiring a vibration signal from the target; (g) ascertaining spectral features of said vibration signal of the target within said most discriminating frequency band at said spectral resolution, and (h) assigning a probability for the target for being either said first or said second object in accordance to a correlation score of said spectral features of the target with said immutable features of said vibration spectrum of said first object and said second object.