Automatic speech recognition using acoustic sub-words and no time alignment

The authors have developed a very successful new approach to automatic speech recognition which incorporates speech knowledge into a mathematical framework and does not require a computationally intensive time alignment/dynamic programming scheme. They transform the speech signal into the spectral domain, segment it into sub-word units and, in turn, perform an additional transformation in the spectral domain to capture the spectral structure within each sub-word unit. The system was shown to perform robustly in hand segmented whole word digit recognition in clean as well as noisy speech. They have now augmented the system with an automatic acoustic sub-word segmentation routine and tested the performance of this integrated system with the TI isolated word database and the confusable E set