Construction of discriminative positive time-frequency distributions

Positive time-frequency energy distributions (PTFD) are suitable for studying the non-stationary dynamics of a signal. Instantaneous features extracted from the PTFD are often used in classification applications where the discriminatory clue lies in the non-stationary behavior of the signal. From a classification point of view it would be desirable to identify and extract instantaneous features that correspond to only the discriminative portion of the signal. By doing so we get an added advantage of eliminating the overlap from the non-discriminatory portion of the signal in the instantaneous feature extraction process. In this paper, we propose a front-end processing using a novel time-width versus frequency band mapping that facilitates the construction of PTFD corresponding to only the discriminatory portion of the signal. Instantaneous features extracted from these PTFDs are readily discriminative and attractive for classification and characterization applications. The proposed method is demonstrated with a speech classification example.