Multi-scale feature based convolutional neural networks for large vocabulary speech recognition
Tong Fu, Xihong H. Wu · 2017
Deep learning has brought a breakthrough to the performance of speech recognition. The speech recognition systems based on deep neural networks have obtained the state-of-the-art performance on various speech recognition tasks. These systems almost utilize the Mel-frequency cepstral coefficients or the Mel-scale log-filterbank coefficients, which are based on short-time Fourier transform. Although these features are designed based on the auditory characteristics of the human, it is a problem that the inherent tradeoff of the temporal and frequency resolution still exists in spectral representations based on short-time Fourier transform. In this paper, we propose a multi-scale method to mitigate the tradeoff and a model architecture that enables to analyze speech at multiple scale. Experiments are conducted on TIMIT and HKUST corpus. We compare the proposed multi-scale features and traditional features at various number of configurations. Experimental results show that the proposed model architecture can obtain significant performance improvement.