Deep Speech 2: End-to-End Speech Recognition in English and Mandarin
Table 15: Comparison of DS1 and DS2 system on noisy speech. “CHiME eval clean” is a noise-free baseline. The “CHiME eval real” dataset is collected in real noisy environments and the “CHiME eval sim” dataset has similar noise synthetically added to clean speech. Note that we use only one of the six channels to test each utterance.
['Noisy Speech Test set', 'Noisy Speech DS1', 'Noisy Speech DS2', 'Noisy Speech Human']
Noisy Speech This dataset has 1320 utterances from the WSJ test set read in various noisy environments, including a bus, a cafe, a street and a pedestrian area. The CHiME set also includes 1320 utterances with simulated noise from the same environments as well as the control set containing the same utterances delivered by the same speakers in a noise-free environment. Differences between results on the control set and the noisy sets provide a measure of the network’s ability to handle a variety of real and synthetic noise conditions. We use a single channel for all our results, since multi-channel audio is not pervasive on most devices. The relative gap between DS2 and human level performance is larger when the data comes from a real noisy environment instead of synthetically adding noise to clean speech.