50 research outputs found
Phone-based cepstral polynomial SVM system for speaker recognition,” in
Abstract We have been using a phone-based cepstral system with polynomial features in NIST evaluations for the past two years. This system uses three broad phone classes, three states per class, and third-order polynomial features obtained from MFCC features. In this paper, we present a complete analysis of the system. We start from a simpler system that does not use phones or states and show that the addition of phones gives a significant improvement. We show that adding state information does not provide improvement on its own but provides a significant improvement when used with phone classes. We complete the system by applying nuisance attribute projection (NAP) and score normalization. We show that splitting features after a joint NAP over all phone classes results in a significant improvement. Overall, we obtain about 25% performance improvement with polynomial features based on phones and states, and obtain a system with performance comparable to a state-of-the-art SVM system
Multi-task Learning for Speaker Verification and Voice Trigger Detection
Automatic speech transcription and speaker recognition are usually treated as
separate tasks even though they are interdependent. In this study, we
investigate training a single network to perform both tasks jointly. We train
the network in a supervised multi-task learning setup, where the speech
transcription branch of the network is trained to minimise a phonetic
connectionist temporal classification (CTC) loss while the speaker recognition
branch of the network is trained to label the input sequence with the correct
label for the speaker. We present a large-scale empirical study where the model
is trained using several thousand hours of labelled training data for each
task. We evaluate the speech transcription branch of the network on a voice
trigger detection task while the speaker recognition branch is evaluated on a
speaker verification task. Results demonstrate that the network is able to
encode both phonetic \emph{and} speaker information in its learnt
representations while yielding accuracies at least as good as the baseline
models for each task, with the same number of parameters as the independent
models
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Feature extraction using non-linear transformation for robust speech recognition on the Aurora database
We evaluate the performance of several feature sets on the Aurora task as defined by ETSI. We show that after a non-linear transformation, a number of features can be effectively used in a HMM-based recognition system. The non-linear transformation is computed using a neural network which is discriminatively trained on the phonetically labeled (forcibly aligned) training data. A combination of the non-linearly transformed PLP (perceptive linear predictive coefficients), MSG (modulation filtered spectrogram) and TRAP (temporal pattern) features yields a 63% improvement in error rate as compared to baseline me frequency cepstral coefficients features. The use of the non-linearly transformed RASTA-like features, with system parameters scaled down to take into account the ETSI imposed memory and latency constraints, still yields a 40% improvement in error rate
Combining Prosodic, Lexical and Cepstral Systems for Deceptive Speech Detection
We report on machine learning experiments to distinguish deceptive from non-deceptive speech in the Columbia-SRI-Colorado (CSC) corpus. Specifically, we propose a system combination approach using different models and features for deception detection. Scores from an SVM system based on prosodic/lexical features are combined with scores from a Gaussian mixture model system based on acoustic features, resulting in improved accuracy over the individual systems. Finally, we compare results from the prosodic-only SVM system using features derived either from recognized words or from human transcriptions
Combination strategies for a factor analysis phone-conditioned speaker verification system
This work aims to take advantage of recent developments in joint factor analysis (JFA) in the context of a phonetically conditioned GMM speaker verification system. Previous work has shown performance advantages through phonetic conditioning, but this has not been shown to date with the JFA framework. Our focus is particularly on strategies for combining the phone-conditioned systems. We show that the classic fusion of the scores is suboptimal when using multiple GMM systems. We investigate several combination strategies in the model space, and demonstrate improvement over score-level combination as well as over a non-phonetic baseline system. This work was conducted during the 2008 CLSP Workshop at Johns Hopkins University