Sparsity-based confidence measure for pitch estimation in noisy speech

In this paper, we propose a confidence measure for the pitch estimation method presented in a parallel paper [1]. The confidence measure is derived based on a sparse representation of the speech harmonic structure. The measurement quantitatively reflects the harmonicity associated with an estimated pitch. It is used to indicate the reliability of the results. Histogram is employed to illustrate the distribution of the measurement obtained from speech signals at low signal-to-noise ratios. It is shown that with the confidence measure, correct results can be effectively identified. By using the confidence measure, an adaptive algorithm for pitch estimation is proposed. Reliable pitch values obtained from preceding estimations are identified and used to predict the local pitch range for subsequent estimations. Parameter of the estimation algorithm is dynamically adjusted according to the predicted pitch range. Experimental results show that with the adaptive algorithm, pitch estimation accuracy is noticeably improved.