Automatic estimation of reverberation time from binaural signals

An estimate of the reverberation time (RT) at the space of usage can be useful in many communications applications, such as augmented reality audio and intelligent hearing aid devices. This paper presents a method to measure the reverberation time from two microphone signals. The analysis is based on locating suitable sound segments for RT analysis by using short-time energy and inter-channel coherence measures, followed by the Schroeder integration method, line fitting and finally statistical analysis. The line fitting is used to estimate the slope of the decay. In this paper, we propose a method where the slope is estimated in the region that maximizes the correlation coefficient of the least squares method. This makes the estimation results more accurate than if fixed limits, e.g., -5 to -25 dB on the decay curve, were used, thanks to the absence of the systematic error caused by bending of the decay curves. The system performance was evaluated using a real-time version of the algorithm.