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The array output for a distributed source can be approximated by the superposition of the array response to a large number of closely spaced point sources. In the limit, a distributed source corresponds to an infinite number of point sources. In this approximation, the number of free parameters increases with the number of point sources. In this paper, we show that if the point sources (approximation...
The performances of adaptive array algorithms are known to degrade in scenarios with moving interfering sources. Recently, several robust approaches have been proposed to overcome this problem. Below, we compare conventional and robust algorithms using shallow sea sonar data with moving co-channel interference originated from shipping noise. This data set was recorded by a towed horizontal Uniform...
A modified Constant Modulus Algorithm (CMA) is proposed for real signals impinging upon an array. The algorithm solves the mix-up problem of CMA which occurs when real signals propagate through complex channels. Moreover, it decreases computational complexity and extends the maximum number of real sources which can be resolved by a given array. Simulations are presented to support the analysis.
This paper addresses the problem of enhancing a speech signal acquired by a microphone array used for hands-free voice communication applications. A new algorithm based on the coherence function developed in the wavelet domain and applied to the beamforming output signal is presented. The wavelet coherence function based nonlinear post-filtering provides a further noise suppression. Its performances...
Subspace fitting methods have grown popular for parameter estimation in many different application, for example sensor array signal processing, blind channel identification and identification of linear state space systems. Here we show that similar procedures can be used even for data models where the noise free signal gives a full rank contribution to the covariance matrix. A general weighting is...
The purpose of this paper is to propose the design and the use of a Neural Network for model order selection The proposed neural network learns from real life situation by constructing an input/output mapping (for detection) which brings to mind the notion of non parametric statistical inference. Such a strategy can improve performances of traditional tests relying on linearity, stationarity and second...
In this paper a new variation of Hough Transform is proposed. It can be used to detect shapes or curves in an image, with better accuracy, especially in noisy images. It is based on a fuzzy split of the Hough Transform parameter space. The parameter space is split into fuzzy cells which are defined as fuzzy numbers. This fuzzy split of the parameter space provides the advantage to use the uncertainty...
this paper proposes a directional noise suppressor with a specified constant beamwidth. A directional gain is calculated based on interchannel phase difference and combined with a spectral gain commonly used in single-channelnoise suppressors (NSs). The beamwidth can be specified as passband edges of the directional gain. In order to implement frequency-independent constant beamwidth, frequency-proportionate...
In this paper, a method of adaptive noise suppression combining spatially robust fixed beamforming and the TRINICON blind source separation algorithm is presented. A multichannel sensor array is first processed using complementary fixed beamformers into maximum and minimum SINR channels. The channels form the inputs to a single 2×2 second-order statistics TRINICON-BSS system which adaptively compensates...
Many vision and augmented reality applications require knowing the rotation of the camera relative to an object or scene. In this paper we propose to create a structured light field designed explicitly to simplify the estimation of camera rotation. The light field is created using a lenticular sheet with a color coded backplane pattern, creating a lightfield where the observed color depends on the...
An intrinsic issue of large-array beamforming and signal processing in random-inhomogeneous environments is known to be considerable degradation of signal coherence in space domain. Such a scenario arises in many applications, and array operations in underwater sound channels with emphasis on long-range sound propagation is one of the most typical cases. Another key issue is here the multimode propagation...
In this work, we investigate the efficacy of Micro Electro-Mechanical System (MEMS) microphones, a newly developed technology of very compact sensors, for multichannel speech enhancement. Experiments are conducted on real speech data collected using a MEMS microphone array. First, the effectiveness of the array geometry for noise suppression is explored, using a new corpus containing speech recorded...
Source localization has been studied in the spatial domain using differential geometry in earlier work. However, parameters of the sensor array manifold have hitherto not been investigated for source localization in spherical harmonics domain. The objective of this work is to represent and model the manifold surface using differential geometry. The system model for source localization over a spherical...
We investigated the basic principle of how spatial signals should be captured with a microphone array to estimate each source signal and its practical implementation. Most conventional studies on array signal processing have been focused on the design of beamforming and Wiener filters. To achieve further effective noise reduction, designing an optimum array structure to segregate a target from other...
The ability of robots to listen to several things at once with their own “ears”, that is, robot audition, is an important factor in improving interaction and symbiosis between humans and robots. The critical issue in robot audition is real-time processing and robustness against noisy environments with high flexibility to support various kinds of robots and hardware configurations. This paper first...
The Square Kilometre Array (SKA) will form the largest radio telescope ever built and such a huge instrument in the desert poses enormous engineering and logistic challenges. Algorithmic and architectural breakthroughs are needed.
This work focuses on an adaptive beamformer in a hearing aid application using a generalized sidelobe canceller structure (GSC). In this application, the constraint and blocking matrices in the GSC structure are specifically designed using an estimate of the transfer functions between the target source and the microphones to ensure optimal beamformer performance. We show that, in practice, the GSC...
In this paper we propose a novel multi-channel algorithm to separate simultaneous speakers in an environment where the microphone array is subject to movement. When the microphones are mounted to a person's head, for instance, the movements can lead to ambiguities with respect to the sources and to distortions in the processed signal. The proposed system estimates the direction-of-arrival of the speaker's...
In this paper we investigate the design of the measurement matrix for applying Compressed Sensing (CS) to the problem of Direction Of Arrival (DOA) estimation with antenna arrays. So far, it has been suggested to choose the coefficients randomly since this choice satisfies the restricted isometry property (RIP) with a high probability. We demonstrate that this choice may be sub-optimal since it can...
The size of SKA-Low stations affects calibration of the instrument, and the science that can be performed. We analyse the differences in instrumental calibration when varying station size, for a fixed total effective area and array layout. The Cramer-Rao Bound (CRB) is used as a metric to quantify the theoretical optimal performance for estimating direction-dependent station gains (amplitude and phase),...
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