On DNN posterior probability combination in multi-stream speech recognition for reverberant environments
A multi-stream framework with deep neural network (DNN) classifiers has been applied in this paper to improve automatic speech recognition (ASR) performance in environments with different reverberation characteristics. We propose a room parameter estimation model to determine the stream weights for DNN posterior probability combination with the aim of obtaining reliable log-likelihoods for decoding. The model is implemented by training a multi-layer perceptron to distinguish between various reverberant environments. The method is tested in known and unknown environments against approaches based on inverse entropy and autoencoders, with average relative word error rate improvements of 46% and 29%, respectively, when performing multi-stream ASR in different reverberant situations.