High improvement of speaker identification and verification by combining MFCC and phase information

In conventional speaker recognition methods based on MFCC, phase information has been ignored. We proposed a method that integrated the phase information with MFCC on a speaker identification method, and a preliminary experiment was performed. In this paper, we propose a new modified feature parameter (that is, coordidates on an unit circle) obtained from the original phase information, and evaluated it by using speech database consisting of normal, fast and slow speaking modes. The speaker identification experiments were performed using NTT database which consists of sentences uttered by 35 Japanese speakers (22 males and 13 females) on five sessions over ten months. Each speaker uttered only 5 training utterances at a normal speaking mode (about 20 seconds in total). The proposed new phase information was more robust than the original phase information for all speaking modes. By integrating the new phase information with the MFCC, the speaker identification error rate was remarkably reduced for normal, fast and slow speaking rates in comparison with a standard MFCC-based method. In this paper, speaker verification experiments were also evaluated using the phase information. The experiments show that the phase information is also very useful for the speaker verification.