| 1. |
- Lei, Shiwen, et al.
(författare)
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A CFAR Adaptive Subspace Detector Based on a Single Observation in System-Dependent Clutter Background
- 2014
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Ingår i: IEEE Transactions on Signal Processing. - 1053-587X. ; 62:20, s. 5260-5269
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, the problem of detecting target in system-dependent clutter (SDC) background with a single observation from the test cell is researched. Classical detectors, such as the generalized likelihood ratio detectors (GLRDs) and the adaptive matched filters (AMFs), etc., usually deal with the clutter and the noise as a whole. The low rank detectors (LRDs) make use of the low rank property of the clutter to improve the detection performance. However, the performance of LRDs degrades when the signal is not orthogonal with respect to (w.r.t.) the clutter. In this paper, an adaptive subspace detector for SDC (SDC-ASD) background which deals with the clutter and the noise separately is proposed. The SDC-ASD designs the test statistic by replacing the signal and the clutter covariance matrix with their maximum likelihood estimations (MLEs). Its theoretical false alarm probability and detection probability are analytically deduced. Analytical results show that the test statistic has the form of non-central distribution. Besides, it is shown that the SDC-ASD has constant false alarm rate (CFAR) performance w.r.t. the clutter and the noise. Numerical experiments are provided to validate the detection performance of the SDC-ASD in dealing with the target detection in SDC background.
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| 2. |
- Lei, Shiwen, et al.
(författare)
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Adaptive polarimetric detection method for target in partially homogeneous background
- 2015
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Ingår i: Signal Processing. - : Elsevier BV. - 0165-1684. ; 106, s. 301-311
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Tidskriftsartikel (refereegranskat)abstract
- In this paper,the problem of enhancing the detection performance of detector for target in partially homogeneous background is addressed. ased on a general measurement model, a new constant false alarm rate (CFAR) adaptive matched detector (AMD) is proposed through a two-step design procedure. The detection performance of the AMD is theoretically analyzed. Then, the correctness of the analytical results and the effectiveness of the AMD are validated through numerical experiments and IPIX radar data. To further improve the detection performance of AMD, optimal polarimetric waveform design is approached. The waveform is designed by optimally selecting the transmitted polarization that maximizes a non-central parameter of the detection probability. Numerical experiments are provided to validate the performance improvement by comparing the optimal AMD with the optimal adaptive subspace detector(ASD) and the fixed AMDs. Comparison results show that a gain of 1–5 dB is obtained by the optimal AMD.
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| 3. |
- Lei, Shiwen, et al.
(författare)
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Analyses of the performance of adaptive subspace detector on fluctuating target detection in system-dependent clutter background
- 2016
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Ingår i: IET Radar, Sonar and Navigation. - : Institution of Engineering and Technology (IET). - 1751-8784 .- 1751-8792. ; 10:9, s. 1635-1642
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Tidskriftsartikel (refereegranskat)abstract
- The adaptive subspace detector in system-dependent clutter background (SDC-ASD) is proved to be able to improve the detection performance for deterministic target detection in the authors' previous study. However, the exact performance of the SDC-ASD for fluctuating target detection is still unknown. In this study, with the aid of matrix decomposition theory, the analytical performance of the SDC-ASD for detecting fluctuating target is considered and assessed. At the design stage, the rigorous mathematical derivation processes for the exact theoretical detection performance of the SDC-ASD for fluctuating target detection is derived. The theoretical results, which have explicitly expressions for both the false alarm probability and the detection probability, not only provide an effective mathematical method to analyse the fluctuating target detection performance, but also can further simplify the deterministic target detection assessments. At the analysis stage, Monte Carlo simulations are resorted to validate the analytical results. Numerical experiments are conducted to assess the effectiveness of the SDC-ASD for fluctuating target detection. Results show that the SDC-ASD, by dealing separately with the clutter and the noise, performs the best in comparison with its published counterparts, i.e. the generalised likelihood ratio detectors, the adaptive matched filters, the adaptive subspace detectors and the low-rank detectors based on sample covariance matrix.
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| 4. |
- Lei, Shiwen, et al.
(författare)
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Computationality efficient multi-pitch estimation using sparsity
- 2016
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Ingår i: 11th IMA International Conference on Mathematics in Signal Processing.
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Konferensbidrag (refereegranskat)abstract
- In this work, we introduce a computationally efficient multi-pitch estimation algorithm making use of an approximative frequency domain reformulation of a recent block-sparse multi-pitch estimator. Different to most other pitch estimators, the proposed method does not require a prior knowledge of the number of sources present, nor the number of overtones of each such source. Evaluated on measured audio signals, the estimator is shown to offer excellent performance at a low computational cost.
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| 5. |
- Piatti, Tommaso, et al.
(författare)
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Interference Cancellation in Two-Channel Nuclear Quadrupole Resonance Measurements
- 2017
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Ingår i: 42nd IEEE International Conference on Acoustics, Speech and Signal Processing. - 9781509041176 ; , s. 3351-3355
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Konferensbidrag (refereegranskat)abstract
- Given its high specificity, the use of nuclear quadrupole resonance (NQR) spectroscopy allows for a reliable identification and quantification of substances containing quadrupolar nuclei, such as the 14N nucleus prevalent in many explosives, medicines, and narcotics. Regrettably, the measured signals are typically weak and suffers from interference signals often being several orders of magnitude stronger than the signal of interest. In this work, we propose a two-channel setup allowing for interference cancellation in applications such as demining. The proposed techniques forms an estimate of the interference using the secondary channel, and then removes it from the primary channel. The improved performance of the resulting detector is illustrated using real measurements of NaNO2.
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| 6. |
- Wang, Zhengjun, et al.
(författare)
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Compressed Sensing for Reconstructing Coherent Multidimensional Spectra
- 2020
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Ingår i: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 124:9, s. 1861-1866
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Tidskriftsartikel (refereegranskat)abstract
- We apply two sparse reconstruction techniques, the least absolute shrinkage and selection operator (LASSO) and the sparse exponential mode analysis (SEMA), to two-dimensional (2D) spectroscopy. The algorithms are first tested on model data, showing that both are able to reconstruct the spectra using only a fraction of the data required by the traditional Fourier-based estimator. Through the analysis of the sparsely sampled experimental fluorescence-detected 2D spectra of LH2 complexes, we conclude that both SEMA and LASSO can be used to significantly reduce the required data, still allowing one to reconstruct the multidimensional spectra. Of the two techniques, it is shown that SEMA offers preferable performance, providing more accurate estimation of the spectral line widths and their positions. Furthermore, SEMA allows for off-grid components, enabling the use of a much smaller dictionary than that of the LASSO, thereby improving both the performance and the lowering of the computational complexity for reconstructing coherent multidimensional spectra.
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