Class specific GMM based sparse feature for speech units classification

In this paper, features based on the sparse representation (SR) are proposed for the classification of speech units. The proposed method employs multiple dictionaries to effectively model variations present in the speech signal. Here, a Gaussian mixture model (GMM) is built using spectral features corresponding to frames of all the examples of a speech class. Multiple dictionaries corresponding to different mixture are learned using the respective speech frames. Given a train/test speech frame, minimum spectral distance measure from the GMM means is employed to select an appropriate dictionary. The selected dictionary is used to obtain the sparse feature representation, which is used for the classification of speech units. The effectiveness of the proposed feature is demonstrated using continuous density hidden Markov model (CDHMM) based classifiers for (i) classification of isolated utterances of E-set of English alphabet, (ii) classification of consonant-vowel (CV) segments in Hindi language and (iii) classification of phoneme from TIMIT phonetic corpus. Experimental results reveal that the proposed features outperforms existing feature representations for various speech units classification tasks.