Subband hybrid feature for multi-stream speech recognition

A subband hybrid (SBH) feature is developed for multi-stream (MS) speech recognition. The fullband speech signal is decomposed into multiple subbands, each covers about 3 Bark along the frequency. Speech signal is analyzed by a high-resolution filterbank of 4 filters/Bark and a low-resolution filterbank of 2 filters/Bark to facilitate the representation of both short-term spectral modulation and long-term temporal modulation within a frequency subband. Experiments on TIMIT corpus for English and RATS corpus for Arabic Levantine show that the SBH feature significantly enhances the amount of information being extracted from individual subbands. The MS system with performance monitor achieves a substantial gain in performance over the single-stream baseline.