Journal Papers

Performing Active Noise Control and Acoustic Experiments Remotely

I. Khan, D. Muthusamy, W. Ahmad, B. Sällberg, K. Nilsson, J. Zackrisson, I. Gustavsson, L. Håkansson International Journal of Online Engineering (iJOE), vol. 8, Special Issue 2: REV2012/2, pp. 65-74, 2012 This paper presents a novel and advanced remotely controlled laboratory for conducting Active Noise Control (ANC), acoustic and Digital Signal Processing (DSP) experiments. The laboratory facility, recently developed by Blekinge Institute of Technology (BTH) Sweden, supports remote learning through internet covering beginners level such as simple experimental measurements to…

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Adaptive Fingerprint Image Enhancement with Emphasis on Pre-processing of Data

J. Ström-Bartunek, M. Nilsson, B. Sällberg, I. Claesson IEEE Transactions on Image Processing, vol. 22, 2, pp. 644 – 656, 2012 This article proposes several improvements to an adaptive fingerprint enhancement method that is based on contextual filtering. The term adaptive implies that parameters of the method are automatically adjusted based on the input fingerprint image. Five processing blocks comprise the adaptive fingerprint enhancement method, where four of these blocks are updated in our proposed system. Hence, the proposed overall…

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Non-Coherent Fourth-Order Detector for Impulse Radio Ultra Wideband Systems: Empirical Evaluation Using Channel Measurements

M. Gufran Khan, B. Sällberg, J. Nordberg, F. Tufvesson, I. Claesson Springer Wireless Personal Communications, Vol. 68, No. 1, pp. 27-46, Jan. 2013 Low-complex and low-power non-coherent energy detectors (EDs) are interesting for low data rate impulse radio (IR) ultra wideband (UWB) systems, but suffer from a loss in performance compared to coherent receivers. The performance of an ED also strongly depends on the integration interval (window size) of the integrator and the window position. This paper presents a non-coherent…

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Source localization for multiple speech sources using low complexity non-parametric source separation and clustering

M. Swartling, B. Sällberg, N. Grbic Elsevier Journal of Signal Processing, vol. 91, No. 8, pp. 1781-1788, Aug. 2011 This article presents a new method for localization of multiple concurrent speech sources that relies on simultaneous blind signal separation and direction of arrival (DOA) estimation, as well as a method to solve the intersection point selection problem that arises when locating multiple speech sources using multiple sensor arrays. The proposed method is based on a low complexity non-parametric blind signal…

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Robust Weighted Non-Coherent Receiver for Impulse Radio UWB PPM Signals

M. Gufran Khan, B. Sällberg, J. Nordberg, I. Claesson IEEE Communication Letters, vol. 15, No. 6, pp. 614-616, June 2011 This letter proposes an energy detection based robust weight estimation scheme for pulse-position modulated (PPM) impulse radio ultra-wideband (IR-UWB) signals using weighted non-coherent receiver (WNCR). Conventional data-aided WNCR (DA-WNCR) scheme estimates the weighting coefficients, or channel state information (CSI), using a large number of training symbols over time-varying channels. In contrast, the proposed Robust WNCR (R-WNCR) scheme is non-data-aided (NDA),…

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Statistical Analysis of a Local Quadratic Criterion for Blind Speech Extraction

B. Sällberg, N. Grbic, I. Claesson IEEE Signal Processing Letters, vol. 16, no. 2, pp. 89-92, Feb. 2009 This letter aims at complementing previous empirical work regarding a certain beamforming technique for blind speech extraction that uses a local quadratic approximation of a Kurtosis expression. It is shown here that the proposed method possesses a fixed-point property which means that it remains at an optimal solution once this solution has been reached. The proposed method’s fixed-point property is valid for…

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Complex-valued Independent Component Analysis for Online Blind Speech Extraction

B. Sällberg, N. Grbic, I. Claesson IEEE Transaction on Audio, Speech and Language Processing, vol. 16, no. 8, pp. 1624-1632, Nov. 2008 This paper presents a theoretical analysis of a certain criterion for complex-valued independent component analysis (ICA) with a focus on blind speech extraction (BSE) of a spatio-temporally nonstationary speech source. In the paper, the proposed criteria denoted KSICA is related to the well-known FastICA method with the Kurtosis contrast function. The proposed method is shown to share the…

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On a Method for Improving Impulsive Sounds Localization in Hearing Defenders Directional Aid for Hearing Defenders: Enhancement of Impulsive Sounds using ILD

B. Sällberg, F. Sattar, I. Claesson EURASIP Journal on Audio, Speech, and Music Processing, Special issue on Intelligent Audio, Speech, and Music Processing Applications, 2008 This paper proposes a new algorithm for a directional aid with hearing defenders. Users of existing hearing defenders experience distorted information, or in worst cases, directional information may not be perceived at all. The users of these hearing defenders may therefore be exposed to serious safety risks. The proposed algorithm improves the directional information for…

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