Parametric microphone array spatial filter based on cross-pattern coherence
نویسندگان
چکیده
In this study, we propose an implementation of the cross-pattern coherence (CroPaC) spatialfiltering technique. This parametric algorithm utilizes the normalized cross-spectral density between signals from microphones of different orders as a criterion for focusing in specific directions and is implemented by using directional microphones placed in the same look direction and have the same magnitude and phase response. A spatial-filter is calculated from a multichannel input and is used to assign attenuation values to a coincidentally captured audio signal. The proposed algorithm is simple to implement and offers the capability of coping with interfering sources at different azimuthal locations with or without the presence of diffuse sound. In contrary to previous techniques, which rely on the performance of the beamformer for source focusing, CroPaC provides additional beamforming capabilities with increased performance at low frequencies. Significant improvement is demonstrated over traditional beamforming techniques in terms of noise reduction and focusing capabilities. Sound examples of the algorithm can be fond online in http://www.acoustics.hut.fi/projects/cropac/soundExamples/
منابع مشابه
Parametric Acoustic Camera for Real-time Sound Capture, Analysis and Tracking
This paper details a software implementation of an acoustic camera, which utilises a spherical microphone array and a spherical camera. The software builds on the Cross Pattern Coherence (CroPaC) spatial filter, which has been shown to be effective in reverberant and noisy sound field conditions. It is based on determining the cross spectrum between two coincident beamformers. The technique is ...
متن کاملMicrophone array post-filter based on noise field coherence
This paper introduces a novel technique for estimating the signal power spectral density to be used in the transfer function of a microphone array post-filter. The technique is a generalization of the existing Zelinski post-filter, which uses the autoand cross-spectral densities of the array inputs to estimate the signal and noise spectral densities. The Zelinski technique, however, assumes zer...
متن کاملPhase-Based Adaptive Estimation of Magnitude-Squared Coherence Between Turbofan Internal Sensors and Far-Field Microphone Signals
A cross-power spectrum phase based adaptive technique is discussed which iteratively determines the time delay between two digitized signals that are coherent. The adaptive delay algorithm belongs to a class of algorithms that identifies a minimum of a pattern matching function. The algorithm uses a gradient technique to find the value of the adaptive delay that minimizes a cost function based ...
متن کاملFlight Path Estimation Using Multipath Delay Measurements from a Wide Aperture Acoustic Array
The flight path of an aircraft travelling at constant velocity and constant altitude is described by a set of five motion parameters which can be estimated using a ground-based wide aperture acoustic array. The narrowband motion parameter estimation method, based on the Doppler effect, requires the aircraft to emit an acoustic tone that is often absent in the case of a jet aircraft. The motion ...
متن کاملCar Speech Enhancement Using Microphone Array Beamforming and Post Filters
This paper presents a speech enhancement method to suppress the car noise interference. A linear microphone array is adopted for far-talking speech acquisition and delayand-sum beamforming noise reduction. We exploit an effective time delay estimator using the coherence function between the reference microphone and the beamformed speech. To further enhance the beamformed speech, we design an im...
متن کامل