An LSTM-CTC based verification system for proxy-word based OOV keyword search

Proxy-word based out of vocabulary (OOV) keyword search has been proven to be quite effective in keyword search. In proxy-word based OOV keyword search, each OOV keyword is assigned several proxies and detections of the proxies are regarded as detections of the OOV keywords. However, the confidence scores of these detections are still those of the proxies from lattices. To obtain a better confidence measure, we employ an LSTM-CTC verification method in this work and the confidence scores are regenerated. OOV keyword search results on the evalpart1 dataset of the OpenKWS16 Evaluation have shown consistent improvement and the maximum relative improvement can reach 21.06% for the MWTW metric.