IEEE/ACM TRANSACTIONS ON AUDIO, SPEECH, AND LANGUAGE PROCESSING
Abstract
In acoustic array processing, beamforming is a class
of algorithms commonly used to estimate the position of a radiating
sound source. This paper presents a diagonal unloading
(DU) transformation method for the conventional response power
beamforming to achieve robust localizationwith lowcomputational
complexity. The transformation is obtained by subtracting an opportune
diagonal matrix from the covariance matrix of the array
output vector. Specifically, the DU beamformer aims at subtracting
the signal subspace from the noisy signal space. It is, hence, a datadependent
covariance matrix conditioning method. We show how
to calculate precisely the unloading parameters, and we present a
comparison of the proposedDUbeamforming, the robustminimum
variance distortionless response (MVDR) filter, and the multiple
signal classification (MUSIC) method, in terms of their respective
eigenanalyses. Theoretical analysis and experiments conducted on
both simulated and real acoustic data demonstrate that the DU
beamformer localization performance is comparable to that of robustMVDRandMUSIC.
Since its computational cost is equivalent
to that of a conventional beamformer, the proposed DU beamformer
method can, thus, be very attractive due to its effectiveness
and computational efficiency.
