Abstract
Recently, there has been an increased interest in the
use of the time-delay estimation (TDE) technique to locate and
track acoustic sources in a reverberant environment. Typically,
the delay estimate is obtained through identifying the extremum
of the generalized cross-correlation (GCC) function or the
average magnitude difference function (AMDF). These estimators
are well studied and their statistical performance is well
understood for single-path propagation situations. However, fewer
efforts have been reported to show their performance behavior in
real reverberation conditions. This paper reexamines the GCC- and
AMDF-based TDE techniques in real room reverberant and noisy
environments. Our contribution is threefold. First, we propose a
weighted cross-correlation (WCC) estimator in which the GCC
function is weighted by the reciprocal of AMDF. This new method
can sharpen the peak of the GCC function, which corresponds to
the true time delay and thus leads to a better estimation
performance as compared to the conventional GCC estimator. Second,
we propose a modified version of the AMDF (MAMDF) estimator in
which the delay is determined by jointly considering the AMDF and
the average magnitude sum function (AMSF). Third, we compare the
performance of the GCC, AMDF, WCC, and MAMDF estimators in real
reverberant and noisy environments. It is shown that the AMDF
estimator can yield better performance in favorable noise
conditions and is slightly more resilient to reverberation than
the GCC method. The GCC approach, however, is found to outperform
the AMDF method in strong noisy environments. Weighting the
correlation function by the reciprocal of AMDF can improve the
performance of the GCC estimator in reverberation conditions, yet
its improvement in noisy environments is limited. The MAMDF
algorithm can enhance the AMDF estimator in both reverberant and
noisy environments.