MAP-based perceptual modeling for noisy speech recognition

This study presents a maximum a posteriori (MAP) based perceptual modeling approach to deal with the issue of recognition degradation in noisy environment. In this approach, MAP-based noise detection is first applied to identify the noise segment in an utterance. Subtractive-type enhancement algorithm with masking properties of the human auditory system is then used to reduce the noise effect. Finally, MAP-based incremental noise model adaptation is developed to overcome the model inconsistencies between training and testing environments. For performance evaluation of the proposed approach, a Mandarin keyword recognition system was constructed. The experimental results show that the proposed approach achieves a better recognition rate compared to the audible noise suppression (ANS) and parallel model combination (PMC) methods.