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Speaker Change Detection using Support Vector Machines. V.Kartik, D.Srikrishna Satish and C.Chandra Sekhar Speech and Vision Laboratory Department of Computer Science and Engineering Indian Institute of Technology Madras, Chennai – India. Speaker Change Detection.
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Speaker Change Detection using Support Vector Machines V.Kartik, D.Srikrishna Satish and C.Chandra Sekhar Speech and Vision Laboratory Department of Computer Science and Engineering Indian Institute of Technology Madras, Chennai – India
Speaker Change Detection • Automatic segmentation of multispeaker speech data into data of one speaker only • Dissimilarity of distributions of the data before and after a speaker change point • Proposal: Speaker change detection as a pattern classification problem • Patterns extracted from the data around the speaker change points as positive examples • Patterns extracted from the data between the speaker change points negative examples
Speaker Change Detection using SVMs • SVM trained using the positive and negative examples of speaker change points • The SVM to scan the multispeaker data to hypothesize speaker change points • Main issues: - Speaker independent detection of the points - Silence regions before speaker change points - Varying durations of speaker turns - Length of the window used for extraction of patterns - Large dimension of segmental pattern vectors - Large number of false alarms
Speaker Change Point Hypothesization using Fixed Duration Window based Patterns • Input: The continuous speech signal of multispeaker speech data without silence regions • The SVM is trained with pattern vectors extracted from the fixed length windows of n frames • Sliding window method: A test pattern is extracted for every n frames with one frame shift. • The test patterns with positive output of the SVM are hypothesized as speaker change points • Several hypotheses may be spurious.
False Alarm Reduction • Two methods are considered for reduction of spurious hypotheses (false alarms) • 1st method: A threshold of 5 frames on the duration of speaker turns. • 2nd method: The false hypotheses on validation data are used as the negative examples in training an SVM for false alarm reduction.
Studies on Speaker Change Detection • Extended data of NIST2003 speaker recognition evaluation database • 2-sp conversations, each of about 5 minute duration including 3 for each of M-M, M-F and F-F speaker conversations • Speaker change points are manually marked • Data divided into training, validation and test datasets • Each dataset includes one each of M-M, M-F and F-F • Training dataset for SVM • Validation dataset to derive the negative examples for the false alarm reduction SVM • Test dataset to evaluate the performance of speaker change detection system
Performance of Speaker Change Detection System • # actual speaker change points in test dataset: 282 • # frames in the test dataset: about 16000 • # speaker change points missed (not detected): M • # false alarms: FA
Summary • Speaker change detection as a pattern classification problem. • Fixed duration window method • SVMs to hypothesize the speaker change points. • Methods for reduction of the number of false alarms. • Performance of the proposed method on NIST2003 speaker verification database.