The use of a microphone array for hands-free continuous speech recognition in noisy and reverberant environment is investigated. An array of four omnidirectional microphones is placed at 1.5 m distance from the talker; given the array signals, a Time Delay Compensation (TDC) module provides a beamformed signal, that is shown effective as input to a Hidden Markov Model (HMM) based recognizer. Given a small amount of sentences collected from a new speaker in a real environment, HMM adaptation further improves recognition rate. These results are confirmed both by experiments conducted in a noisy office environment and by simulations. In the latter case, different SNR and reverberation conditions were recreated by using the image method to reproduce synthetic array microphone signals
Experiments of Speech Recognition in a Noisy and Reverberant Environment using a Microphone Array and HMM Adaptation
Giuliani, Diego;Omologo, Maurizio;Svaizer, Piergiorgio
1996-01-01
Abstract
The use of a microphone array for hands-free continuous speech recognition in noisy and reverberant environment is investigated. An array of four omnidirectional microphones is placed at 1.5 m distance from the talker; given the array signals, a Time Delay Compensation (TDC) module provides a beamformed signal, that is shown effective as input to a Hidden Markov Model (HMM) based recognizer. Given a small amount of sentences collected from a new speaker in a real environment, HMM adaptation further improves recognition rate. These results are confirmed both by experiments conducted in a noisy office environment and by simulations. In the latter case, different SNR and reverberation conditions were recreated by using the image method to reproduce synthetic array microphone signalsI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
