Robust speech recognition using cepstral domain missing data techniques and noisy masks
Hugo Van hamme · 2004
Missing data techniques (MDT) have been shown to be an effective method for curing the performance degradation of HMM-based speech recognition systems operating on noisy signals. However, a major drawback of the approach is that MDT requires that the acoustic model be expressed as a mixture of diagonal Gaussians in the log-spectral domain, whereas a higher accuracy can be obtained with Gaussian mixtures in the cepstral domain. The paper describes a recognizer based on the recently described cepstral-domain MDT approach using missing data masks computed from the noisy signal. It exploits a novel decision criterion that integrates harmonicity with signal-to-noise ratio and which makes minimal assumptions on the noise. The system is shown to exhibit a recognition accuracy that is comparable to the ETSI advanced front-end reference.