Deep Neural Network-Hidden Markov Model Hybrid Systems

In this chapter, we describe one of the several possible ways of exploiting deep neural networks (DNNs) in automatic speech recognition systems the deep neural network-hidden Markov model (DNN-HMM) hybrid system. The DNN-HMM hybrid system takes advantage of DNN's strong representation learning power and HMM's sequential modeling ability, and outperforms conventional Gaussian mixture model (GMM)-HMM systems significantly on many large vocabulary continuous speech recognition tasks. We describe the architecture and the training procedure of the DNN-HMM hybrid system and point out the key components of such systems by comparing a range of system setups.