Parametric binaural rendering utilizing compact microphone arrays

The spatial capture patterns according to head-related transfer-functions (HRTFs) can be approximated using linear beamforming techniques. However, assuming a fixed spatial aliasing frequency, with reduction of the number of sensors and thus the array size, the linear approach leads to an excessive amplification of the microphone noise, unless the beam patterns are made broader than determined by the HRTFs. An adaptive technique is proposed that builds upon the assumption that the binaural perception is largely determined by a set of short-time inter-aural parameters in frequency bands. The parameters are estimated from the noisy HRTF beam pattern signals as a function of time and frequency. As a result of temporal averaging, the effect of the noise is mitigated while the perceptual spatial information is preserved. Signals with higher SNR from broader patterns are adaptively processed to obtain the parameters from the estimation stage by means of least-squares optimized mixing and decorrelation. Listening tests confirmed the perceptual benefit of the proposed approach with respect to linear techniques.