Cross Pattern Coherence Algorithm for Spatial Filtering Applications Utilizing Microphone Arrays

Delikaris-Manias, Symeon; Pulkki, Ville

doi:10.1109/tasl.2013.2277928

Cited by 20 publications

(15 citation statements)

References 21 publications

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“…• the output of an omnidirectional microphone chosen as the 0 th order spherical harmonic signal, (O), • the output of a third order axisymmetric constantdirectivity beam beamformer, (BF), • the output of an MVDR beamformer, (M), • the output of a multichannel Wiener filter formulated as a single-channel Wiener spectral filter and an MVDR [60], (WF), • the output of a static beam pattern cross-spectrum based spatial filter according to [16], (C), and • the proposed adaptive beam pattern spatial filter, (LC).…”

Section: Evaluation With Instrumental Measuresmentioning

confidence: 99%

“…All the reproduction modes were obtained by processing the simulated recording of the microphone array. The reference ideal was the dry sound source, C is the output of the cross pattern coherence spatial filter [16], LC is the proposed method, M is the output of an idealised MVDR beamformer with the steering vector known a priori, and O is the output of the 0 th spherical harmonic signal.…”

Section: Evaluation With Listening Testsmentioning

confidence: 99%

“…Smoothing techniques and spectral floor adjustments have been applied to mitigate these artifacts. For example, in [14]- [16] the energetic estimates are smoothed with a one pole recursive filter. The appliance of the smoothing techniques suggests that the robustness of the spectral estimation for various types of acoustic scenes is a major issue, and is thus one of the focus points in the present study.…”

Section: Introductionmentioning

confidence: 99%

“…A recent class of beamformers, which includes the technique proposed in [16] as well as the technique proposed in the present study, estimates the energy of the target signal using cross-spectral density estimates of two beamformers with the constraints that their maximum sensitivity and equal phase are on the look direction. When these constraints are met, the effects of the noise and interferers are suppressed when the time-averaging interval is increased while the energy of the source at the look direction is retained.…”

Section: Introductionmentioning

confidence: 99%

“…This class of techniques omits the requirement of knowledge of the sound field, and thus provides robustness for complex acoustic scenes. The derivation of the post-filter in the cross-pattern coherence algorithm (CroPaC), [16], relies on the calculation of the crossspectrum of two static beam patterns corresponding to a different order of cylindrical harmonics, and the desired features of the noise orthogonality for the spectral estimation were demonstrated. However, it relies on the manual selection of the two static beampatterns and therefore the spatial selectivity of the beampatterns affects the overall performance.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Signal-Dependent Spatial Filtering Based on Weighted-Orthogonal Beamformers in the Spherical Harmonic Domain

Delikaris-Manias

Vilkamo

Pulkki

2016

IEEE/ACM Trans. Audio Speech Lang. Process.

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Spatial filtering with microphone arrays is a technique that can be utilized to obtain the signal of a target sound source from a specific direction. Typical approaches in the field of audio underperform in practical environments with multiple sound sources and diffuse sound. In this contribution we propose a post-filtering technique to suppress the effect of interferers and diffuse sound. The proposed technique utilizes the cross-spectral estimates of the output of two beamformers to formulate a timefrequency soft masker. The beamformers' outputs are used only for parameter estimation and not for generating an audio signal. Two sets of beamformer weights, a constant and an adaptive, are applied to the microphone array signals for the parameter estimation. The weights of the constant beamformer are designed such that they provide a spatially narrow beam pattern that is time and frequency invariant, having a unity gain towards the direction of interest. The weights of the adaptive beamformer are formulated using linearly constrained optimization with the constraint of weighted orthogonality with respect to the constant beamformer weights, as well as the unity gain towards the look direction. The orthogonality constraint provides diffuse sound suppression while the unity gain distortionless response. The cross spectrum of these two beamformers provides the target energy at a given look direction for the post filter. The study focuses on compact microphone arrays with which the typical beamforming techniques feature a trade-off between noise amplification and spatial selectivity, especially in the low frequency region. The proposed method is evaluated with instrumental measures and listening tests under different reverberation times, in dual and multi-talker scenarios. The evaluation shows that the proposed method provides a better performance when compared with a previous state-of-the-art spatial filter based on cross-pattern coherence, a linearly constrained beamformer and a Wiener postfilter.

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Section: Evaluation With Instrumental Measuresmentioning

confidence: 99%

Section: Evaluation With Listening Testsmentioning

confidence: 99%