Analysis of Prediction Intervals for Non-Intrusive Estimation of Speech Clarity Index
Pablo Peso Parada, Dushyant Sharma, Patrick A. Naylor, Toon van Waterschoot · 2016
We present an analysis of prediction intervals for a non-intrusive method to estimate the clarity index (C50). The method employed to estimate C50 is a data driven approach that extracts multiple features from a reverberant speech signal which are then used to train a bidirectional long-short term memory model which maps the feature space into the target C50 value. The prediction intervals are derived from the standard deviation of the per-frame C50 estimates. This approach was shown to provide a coverage probability of 80%, i.e. 80% of times the ground truth lies between the estimated intervals, where the interval bounds are computed by using 5.6 times the standard deviation of the per-frame estimates. This accuracy is shown to be consistent with other noisy reverberant environments.