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: A Two-Sensor Noise Reduction System: Applications for Hands-Free Car Kit | EURASIP Journal on Applied Signal Processing 2003 11 1125-1134 2003 Hindawi Publishing Corporation A Two-Sensor Noise Reduction System Applications for Hands-Free Car Kit Alexandre Guerin Laboratoire Traitement du Signal et de l lmage Universite de Rennes 1 Bat. 22 35042 Rennes Cedex France Email Regine Le Bouquin-Jeannes Laboratoire Traitement du Signal et de l Image Universite de Rennes 1 Bat. 22 35042 Rennes Cedex France Email Gerard Faucon Laboratoire Traitement du Signal et de l lmage Universite de Rennes 1 Bat. 22 35042 Rennes Cedex France Em ail Received 24 September 2002 and in revised form 27 March 2003 This paper presents a two-microphone speech enhancer designed to remove noise in hands-free car kits. The algorithm based on the magnitude squared coherence uses speech correlation and noise decorrelation to separate speech from noise. The remaining correlated noise is reduced using cross-spectral subtraction. Particular attention is focused on the estimation of the different spectral densities noise and noisy signals power spectral densities which are critical for the quality of the algorithm. We also propose a continuous noise estimation avoiding the need of vocal activity detector. Results on recorded signals are provided showing the superiority of the two-sensor approach to single microphone techniques. Keywords and phrases two-sensor noise reduction hands-free telephony coherence cross-spectral subtraction noise estimation optimization. 1. INTRODUCTION Hands-freecommunication has undergone huge developments in the past two decades. This technology is considered to have added value in terms of comfort and security for the users. Unfortunately it is characterized by strong disturbances namely echo and ambient noise which lead to unacceptable communication conditions for the far-end user. In highly adverse conditions such as the interior of a running .
