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Baltic Congress on Future Internet Communications (BCFIC Riga)

作者： Claudio Salvadori Matteo Petracca Riccardo Pelliccia Marco Ghibaudi Paolo Pagano Real-Time Systems Laboratory Scuola Superiore Sant' Anna Pisa Italy Scuola Superiore SantAnna Research Unit Consorzio Nazionale Interuniversitario per le Telecomunicazioni Pisa Italy National Laboratory of Photonic Networks Consorzio Nazionale Interuniversitario per le Telecomunicazioni Pisa Italy

Video streaming applications in wireless sensor networks are attractive for enabling new pervasive high value services. The reduced amount of available bandwidth in such networks imposes the transmission of small size video frames at very low frame rates. Moreover, when compression techniques cannot be applied, due to constrained computational capabilities of sensor nodes, and uncompressed video frames must be sent through the network, lower image sizes and frame rates must be adopted. In such a scenario, when higher frame rates are required or multiple video streams must be enabled the required transmission bandwidth of each stream must be reduced. In this paper we present a low-complexity algorithm based on change detection which reduces the transmission bandwidth of a video stream based on raw images. Performance results show how the proposed technique can reduce the transmission bandwidth up to 87.22% and 66.78%, with respect to a flat video stream transmission, when low and high changes are experienced in the monitored scene.

关键词： Streaming media Bandwidth Image coding Wireless sensor networks PSNR change detection algorithms Transform coding

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Unsupervised Speaker change detection for Mobile Device Recorded Speech

Unsupervised Speaker Change Detection for Mobile Device Reco...

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International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： Olli Vuorinen Johannes Peltola Satu-Marja Makela VTT Technical Research Center of Finland Oulu Finland

In this paper we propose an unsupervised speaker change detection (SCD) system developed for mobile device applications. We use Bayesian information criterion (BIC) to find initial speaker changes, which are then verified or discarded in the second phase by utilizing modified BIC and silence detector information. Silence information usage after initial BIC in decision making is useful to separate real changes from noise peaks. Enhanced peak detector adjusts BIC penalty parameter automatically, which improve the robustness and feasibility. Improved BIC based false alarm compensation (FAC) merges effectively consecutive segments belonging to same speaker. Our experiments have shown the robustness of the algorithm and it produces very satisfactory results for difficult mobile phone recorded speech data.

关键词： Audio recording change detection algorithms Detectors Image segmentation Noise robustness Multimedia databases Video recording Indexing Speech analysis Bayesian methods

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Template-guided inspection of arbitrarily oriented targets

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IET COMPUTER VISION 2008年第3期2卷 150-163页

作者： Alexandropoulos, T. Boutas, S. Loumos, V. Kayafas, E. Natl Tech Univ Athens Sch Elect & Comp Engn Multimedia Technol Lab GR-10682 Athens Greece

The performance of template-based inspection of randomly oriented targets relies on the effective operation of two procedures: image registration and change detection. Each procedure is characterised by its own challenges. Real-time applications require that image registration is performed in an acceptable time with accurate results, regardless of structural distortions. change detection can be hindered by noise fluctuations and illumination variations. An additional challenge in template-guided change detection comes from the fact that the decision needs to be based on a comparison restricted to two frames. The operation principles of a template-guided change detector are analysed. Image registration is based on a wavelet-based method which employs mutual information. A block-based change detection algorithm, which separates content alterations from noise-level fluctuations, illumination variations and shadows, is also analysed. The principles presented are combined for the implementation of a sample template-guided undervehicle surveillance system. The architecture of the system and its experimental results are presented, and practical aspects and considerations regarding the system design are discussed.

关键词： Distortion(Structures) change detection algorithms image registration Building systems Noise levels Oriented

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Enhanced Unsupervised change Detector for Industrial Surveillance Systems

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IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS 2021年第9期68卷 8973-8981页

作者： Shahbaz, Ajmal Jo, Kang-Hyun Univ Ulsan Sch Elect & Comp Engn Ulsan 44610 South Korea

Detecting an intruder that is trespassing a prohibited area is a critical task of intelligent surveillance systems. This task requires a change detector to segment an intruder (foreground object) from the background. The task suffers the inherent drawbacks of change detectors due to the dual-camera sensor (color/IR), illumination changes, night time, static, and camouflaged foreground objects. This article proposes an enhanced unsupervised change detector to compensate for the aforementioned challenges for industrial sterile zone monitoring. The camera switch detection based on skewness patterns detects a switch between the dual-camera sensors (color/IR). The optimal color space selection based on the mean squared error will select tolerant color space (RGB/YCbCr) to illumination changes for modeling the background. In addition, the IR camera frames are contrast-enhanced to tackle the camouflaged intruders during the night. The incoming frames are split into respective channels before modeling the background. The background is modeled by Gaussian mixture models. The adaptive background model update scheme is proposed to tackle the various challenges posed by environment and object such as a static foreground object. The comparison is performed on three databases with top-ranked unsupervised change detection algorithms.

关键词： Cameras Image color analysis Lighting change detection algorithms Switches Adaptation models Computational modeling Camouflaged intruder dual-camera sensors intelligent surveillance systems (ISSs) IR camera night time security system

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Optimized SVD Approach for the detection of Weak Subsurface Targets From Ground-Penetrating Radar Data

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IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 2013年第3期51卷 1635-1642页

作者： Grzegorczyk, Tomasz M. Zhang, Beijia Cornick, Matthew T. Delpsi LLC Newton MA 02458 USA MIT Lincoln Lab Lexington MA 02421 USA

We propose a two-pass ground-penetrating radar (GPR) approach to detect recently buried nonmetallic scatterers whose signals are otherwise undistinguishable from surrounding clutter. The operating framework is based on a pass-1 data collection over an object-free ground and a pass-2 data collection over the same ground, yet at unregistered positions, which may be contaminated by a recently implanted dielectric scatterer. The detection algorithm is based on a modified singular value decomposition approach and is shown to perform significantly better than a direct signal cancellation approach. Validating results are presented on measured target-free data to which synthetic targets of various strengths are added. Multiple realizations along the measurement path of the GPR array provide statistical diversity to the results which is cast as receiving operating curves, showing quantitatively the improved detection threshold of the new method.

关键词： change detection algorithms electromagnetic propagation ground penetrating radar sensor arrays

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Toward Global Soil Moisture Monitoring With Sentinel-1: Harnessing Assets and Overcoming Obstacles

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IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 2019年第1期57卷 520-539页

作者： Bauer-Marschallingere, Bernhard Freeman, Vahid Cao, Senmao Paulik, Christoph Schaufler, Stefan Stachl, Tobias Modanesi, Sara Massario, Christian Ciabatta, Luca Brocca, Luca Wagner, Wolfgang Vienna Univ Technol Dept Geodesy & Geoinformat A-1040 Vienna Austria CNR Res Inst Geohydrol Protect I-06128 Perugia Italy

Soil moisture is a key environmental variable, important to, e.g., farmers, meteorologists, and disaster management units. Here, we present a method to retrieve surface soil moisture (SSM) from the Sentinel-1 (S-1) satellites, which carry C-hand Synthetic Aperture Radar (CSAR) sensors that provide the richest freely available SAR data source so far, unprecedented in accuracy and coverage. Our SSM retrieval method, adapting well-established change detection algorithms, builds the first globally deployable soil moisture observation data set with 1-km resolution. This paper provides an algorithm formulation to be operated in data cube architectures and high-performance computing environments. It includes the novel dynamic Gaussian upscaling method for spatial upscaling of SAR imagery, harnessing its field-scale information and successfully mitigating effects from the SAR's high signal complexity. Also, a new regression-based approach for estimating the radar slope is defined, coping with Sentinel-1's inhomogeneity in spatial coverage. We employ the S-1 SSM algorithm on a 3-year S-1 data cube over Italy, obtaining a consistent set of model parameters and product masks, unperturbed by coverage discontinuities. An evaluation of therefrom generated S-1 SSM data, involving a 1-km soil water balance model over Umbria, yields high agreement over plains and agricultural areas, with low agreement over forests and strong topography. While positive biases during the growing season are detected, the excellent capability to capture small-scale soil moisture changes as from rainfall or irrigation is evident. The S-1 SSM is currently in preparation toward operational product dissemination in the Copernicus Global Land Service.

关键词： change detection algorithms Copernicus image sampling Sentinel-1 soil moisture

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Improved change Detector Using Dual-Camera Sensors for Intelligent Surveillance Systems

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IEEE SENSORS JOURNAL 2021年第10期21卷 11435-11442页

作者： Shahbaz, Ajmal Jo, Kang-Hyun Univ Ulsan Sch Elect & Comp Engn Ulsan 44610 South Korea Univ Ulsan Dept Elect & Comp Engn Ulsan 44610 South Korea

Unauthorized entrance in a prohibited area might create a security risk. An intelligent surveillance system should be able to mitigate such a problem by incorporating a sterile zone monitoring algorithm. The algorithm is challenged by a dual-camera sensors (color/IR), dynamic backgrounds, illumination changes, camouflaged, and static foreground objects, etc. This paper proposes an improved change detector (ICD) to mitigate the above-mentioned challenges. It employs a novel statistical decision criterion (SDC) based on skewness patterns. The SDC helps to differentiate time of day using the camera sensors (color/IR). The input frames are processed according to the time of day. For instance, IR input is image-enhanced to differentiate between camouflaged intruders from the background. Then input goes through Gaussian Mixture Models (GMM) based change detector to segment foreground (intruder). The foreground object is further cleansed using morphological operations for possible isolated noise and holes. The ICD was tested on three datasets and outperformed top-ranked change detection algorithms.

关键词： Image color analysis Sensors Cameras Image enhancement Switches change detection algorithms Computational modeling IR camera camouflaged intruder dual-camera sensors intelligent surveillance systems

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On the use of asymptotics in detection and estimation

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 1996年第5期44卷 1304-1307页

作者： Garth, LM Bresler, Y Coordinated Science Laboratory Department of Electrical and Computer Engineering University of Illinois Urbana-Champaign Urbana-Champaign IL USA

We illustrate the importance of a finite dimensionality assumption when using functions of asymptotic statistics. We also note that asymptotic distributions need to converge uniformly to facilitate algebraic manipulations. Finally, we point to subtleties in using detection statistics stemming from the central limit theorem and Taylor series without entering the large deviations regime.

关键词： Statistical distributions Detectors Discrete Fourier transforms Random variables Taylor series Signal processing algorithms Statistics Limiting change detection algorithms Signal processing

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Quadratic tests for detection of abrupt changes in multivariate signals

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 1999年第9期47卷 2534-2538页

作者： Nikiforov, IV Univ Technol Troyes Dept Genie Syst Informat & Decis Lab Modelizat & Surete Syst Troyes France

This correspondence considers the problem of detecting abrupt changes in the mean of a multivariate Gaussian random signal. A fixed sample size chi(2)-test is compared against the optimum sequential tests (chi(2)-CUSU... 详细信息

关键词： Testing Sequential analysis Vectors Ellipsoids Signal to noise ratio Probability change detection algorithms detection algorithms Delay effects Gaussian distribution

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TRACKING ALGORITHM DESIGNED BY THE LOCAL ASYMPTOTIC APPROACH

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IEEE TRANSACTIONS ON AUTOMATIC CONTROL 1990年第4期35卷 440-443页

作者： WAHNON, E BERMAN, N BEN GURION UNIV NEGEV DEPT MECH ENGNIL-84105 BEER SHEVAISRAEL

The problem of sequential detection of parameter jumps in linear systems with constant noise level is discussed. The detection problem is analyzed by the asymptotic local approach, using the normalized output error sequence as the detection signal. For linear regression, ARMAX, and state-space models, a central limit theorem is proved, transforming the original problem into the problem of detecting an increase in the man of an asymptotically Gaussian distributed scalar process. The performance of the tracking algorithm, which consists of a parameter estimator with decreasing gain and a single Hinkley\'s detector, has been studied by simulations and compared to the performance of constant- and adaptive-gain parameter estimators. The proposed algorithm seems to be superior in performance, requiring only a little, generally negligible, additional computational effort. The algorithm provides the information about the jump times, and the time delay of jump detection seems to be unaffected by the measurement noise level, provided that this level is not affected by the change.

关键词： Algorithm design and analysis Noise level Parameter estimation change detection algorithms Linear systems Signal analysis Signal detection Linear regression Performance gain Detectors

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