Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Sector-Based Detection for Hands-Free Speech Enhancement in Cars | Hindawi Publishing Corporation EURASIP Journal on Applied Signal Processing Volume 2006 Article ID 20683 Pages 1-15 DOI ASP 2006 20683 Sector-Based Detection for Hands-Free Speech Enhancement in Cars Guillaume Lathoud 1 2 Julien Bourgeois 3 and Jurgen Freudenberger3 1IDIAP Research Institute 1920 Martigny Switzerland 2 Ecole Polytechnique Rédérale de Lausanne EPFL 1015 Lausanne Switzerland 3 DaimlerChrysler Research and Technology 89014 Ulm Germany Received 31 January 2005 Revised 20 July 2005 Accepted 22 August 2005 Adaptation control of beamforming interference cancellation techniques is investigated for in-car speech acquisition. Two efficient adaptation control methods are proposed that avoid target cancellation. The implicit method varies the step-size continuously based on the filtered output signal. The explicit method decides in a binary manner whether to adapt or not based on a novel estimate of target and interference energies. It estimates the average delay-sum power within a volume of space for the same cost as the classical delay-sum. Experiments on real in-car data validate both methods including a case with 100 km h background road noise. Copyright 2006 Hindawi Publishing Corporation. All rights reserved. 1. INTRODUCTION Speech-based command interfaces are becoming more and more common in cars for example in automatic dialog systems for hands-free phone calls and navigation assistance. The automatic speech recognition performance is crucial and can be greatly hampered by interferences such as speech from a codriver. Unfortunately spontaneous multiparty speech contains lots of overlaps between participants 1 . A directional microphone oriented towards the driver provides an immediate hardware enhancement by lowering the energy level of the codriver interference. In the Mercedes S320 setup used in this article a 6 dB relative difference is achieved value measured in the car . However an additional software improvement is required to fully .
