For any practical direction estimation and tracking system in array processing, estimating the number of incident signals accurately and tracking its possible changes in an on-line way is a critical requirement. In th...
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ISBN:
(纸本)9782839904506
For any practical direction estimation and tracking system in array processing, estimating the number of incident signals accurately and tracking its possible changes in an on-line way is a critical requirement. In this paper, a new QR-based adaptive detection algorithm is proposed to estimate the coherent/incoherent narrowband signals impinging on a uniform linear array (ULA), where the updating of eigenvalues and the threshold setting are avoided. The effectiveness of the proposed method is verified through numerical examples, and simulation results show that the proposed method has good detection performance to track the number of suddenly appearing/disappearing incident signals or that of closely-spaced signals with time-varying directions.
New bit array pattern and detection algorithm for hard disk drive (HDD) with patterned media are proposed. The width of the reader is larger than a bit width, of which the fabrication cost is lower than a bit-size com...
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New bit array pattern and detection algorithm for hard disk drive (HDD) with patterned media are proposed. The width of the reader is larger than a bit width, of which the fabrication cost is lower than a bit-size compatible reader. It can read several sub-tracks simultaneously, in which the bits are patterned with different phase. The readback signal is superposed by each bit response and we can extract the bit information easily because of its phase difference.
We introduce a novel wire detection algorithm for use in low altitude urban aircraft reconnaissance. A line profile model is described and effectively used to discriminate wires from other linear patterns commonly fou...
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ISBN:
(纸本)9781424421749
We introduce a novel wire detection algorithm for use in low altitude urban aircraft reconnaissance. A line profile model is described and effectively used to discriminate wires from other linear patterns commonly found in urban scenes. The algorithm is able to cope with highly cluttered backgrounds, moderate rain and mist, and with no stabilization of camera. The studied domain is of particular interest to urban search and rescue and military reconnaissance operations. The algorithmpsilas receiver operating characteristic curve is shown, based on a multi-site dataset with 10160 wires spanning in 5576 frames. Encouraging results show up to 37% detection improvement over a previously published baseline algorithm for comparable false alarm rates.
This paper aims at effectively detecting the changes in multi-temporal synthetic aperture radar (SAR) images. Since pixel-based method does not sufficiently utilize the correlation between pixels, it usually may only ...
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This paper aims at effectively detecting the changes in multi-temporal synthetic aperture radar (SAR) images. Since pixel-based method does not sufficiently utilize the correlation between pixels, it usually may only be used in some specific applications. We propose a change detection method that is based upon discrete cosine transform (DCT) classification. It can utilize the correlation between pixels and eliminate unimportant or nuisance forms of changes. It generates a threshold automatically in DCT classification according to the relationship between DCT coefficient and pixel's gray level. In order to eliminate the block effect, we check pixels not only within the target block, but also inside the neighborhood window around the target block. Experimental results show that the proposed method outperforms some recently published pixel-based methods.
Nowadays, millions of people's living and work habits are affected by TV commercials. A feature-based real-time TV commercial detection algorithm is proposed in this work. In terms of the combination of the visual...
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Nowadays, millions of people's living and work habits are affected by TV commercials. A feature-based real-time TV commercial detection algorithm is proposed in this work. In terms of the combination of the visual and acoustic features, and the temporal information, we detect the end and the start boundary of the commercial separately. Then, in order to refine the detecting result further, we address a set of basic features that is easy to distinguish the commercial from general programs. Based on these features, a finite automation is build simultaneously, which well illustrates our detection method clearly. The experimental results show that our algorithm can yield better recall (96.47%) and precision (97.27%) by comparing with current main approaches.
In this paper we propose a novel technique for detecting rotation and scale invariant interest points from the local frequency representation of an image. Local or instantaneous frequency is the spatial derivative of ...
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In this paper we propose a novel technique for detecting rotation and scale invariant interest points from the local frequency representation of an image. Local or instantaneous frequency is the spatial derivative of the local phase, where the local phase of any signal can be found from its Hilbert transform. Local frequency estimation can detect edge, ridge, corner and texture information at the same time and shows high values at those dominant features of an image. For each pixel, we select an appropriate width of the window for computing the derivative of the phase. In order to select the width of the window for any given pixel, we make use of the measure of the extent to which the phases, in the neighborhood of that pixel, are in the same direction. The local frequency map, thus obtained, is then thresholded by employing a global thresholding approach to detect the interest or feature points. Repeatability rate, a performance evaluation criterion for an interest points detector, is used to check the geometric stability of the proposed method under different transformations. We present simulation results of the detection of feature points from an image and the repeatability rate as a function of image rotation and scale changes. The results prove the efficacy of the proposed feature points detection algorithm.
In the paper a problem of analyzing surgeon's right hand wrist trajectory during laparoscopic operation is considered. Based on the results of the analysis detection algorithms to recognize six motions are develop...
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In the paper a problem of analyzing surgeon's right hand wrist trajectory during laparoscopic operation is considered. Based on the results of the analysis detection algorithms to recognize six motions are developed. The motions can be considered as primitives of a surgery from the human scrub nurse point of view. In the analysis, to represent motions the third order polynomials are used. The two proposed algorithms are based on Kohonen maps and boosted decision trees. The performance of the algorithms is tested on surgical operation data.
In communication environments such as power line channel, impulsive noise greatly deteriorates the performance of detection algorithm based on Gauss optimization. This paper introduces a symmetric alpha stable (Salpha...
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In communication environments such as power line channel, impulsive noise greatly deteriorates the performance of detection algorithm based on Gauss optimization. This paper introduces a symmetric alpha stable (SalphaS) distribution to model a statistical model of impulsive noise, and considers that interference in the receiver is a mixture of additional white Gaussian noise (AWGN) and SalphaS noise. Based on this noise model, a nonlinear detector is proposed through the numerical calculation method. Simulations show that the proposed detector is robust, and its performance is slightly worse than the locally optimum (LO) in non-Gaussian environment, however, the key parameters do not need known in advance and its computational complexity is reduced greatly.
With the development of WSNs in the military and commercial fields, the security of WSNs is becoming more and more important. The security threats of wireless sensor networks (WSNs) come from not only the attacks of e...
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With the development of WSNs in the military and commercial fields, the security of WSNs is becoming more and more important. The security threats of wireless sensor networks (WSNs) come from not only the attacks of external attackers but also the byzantine behaviors and selfish behaviors of internal nodes. The classical security mechanisms, namely cryptography and authentication, can prevent some outsider attacks, however, they are noneffective to the attacks and the anomaly behaviors of internal nodes. A reputation-based model for malicious node detection in WSNs is proposed in this paper. In this model, the beta distribution is used to describe the reputation distribution, and the indirect reliability of third-party nodes is introduced. The simulation results show that the proposed model has better performance in terms of resisting the malicious deceit behaviors of high credit-grade nodes.
An algorithm to blindly detect frequency hopping (FH) signals corrupted by white Gaussian noise (WGN) is presented. Any parameters of FH are assumed to be unknown, and the noise power can be either known or unknown. T...
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An algorithm to blindly detect frequency hopping (FH) signals corrupted by white Gaussian noise (WGN) is presented. Any parameters of FH are assumed to be unknown, and the noise power can be either known or unknown. The algorithm is based on the difference in cyclostationarity (CS) between FH signal and WGN. The module of estimation of cyclic autocorrelation is picked up with available received signal as the test statistic. A WGN of which power equals to the average power of received signal is constructed at the received end, and then the maximum module of estimation of cyclic autocorrelation is computed with this WGN as the detection threshold. Simulation results have proved that the proposed algorithm is adequate to the environments in which signal-to-noise ratio (SNR) is higher than -3dB.
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