A Direct Masking Approach to Robust ASR

Recently, much work has been devoted to the computation of binary masks for speech segregation. Conventional wisdom in the field of ASR holds that these binary masks cannot be used directly; the missing energy significantly affects the calculation of the cepstral features commonly used in ASR. We show that this commonly held belief may be a misconception; we demonstrate the effectiveness of directly using the masked data on both a small and large vocabulary dataset. In fact, this approach, which we term the direct masking approach, performs comparably to two previously proposed missing feature techniques. We also investigate the reasons why other researchers may have not come to this conclusion; variance normalization of the features is a significant factor in performance. This work suggests a much better baseline than unenhanced speech for future work in missing feature ASR.