Abstract
We discuss the frequency-domain blind source separation (BSS) of
convolutive mixtures when the number of source signals is large,
and the potential source locations are omnidirectional. The most
critical problem related to the frequency-domain BSS is the
permutation problem, and geometric information is helpful as
regards solving it. In this paper, we propose a method for
obtaining proper geometric information with which to solve the
permutation problem when the number of source signals is large and
some of the signals come from the same or a similar direction.
First, we describe a method for estimating the absolute DOA by
using relative DOAs obtained by the solution provided by
independent component analysis (ICA) and the far-field model.
Next, we propose a method for estimating the spheres on which
source signals exist by using ICA solution and the near-field
model. We also address another problem with regard to
frequency-domain BSS that arises from the circularity of
discrete-frequency representation. We discuss the characteristics
of the problem and present a solution for solving it. Experimental
results using eight microphones in a room show that the proposed
method can separate a mixture of six speech signals arriving from
various directions, even when two of them come from the same
direction.