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作者： Taylor, Edward I. University of Texas – Austin

学位级别：博士

Plasma turbulence intermittency is investigated in the Texas Helimak, a simple magnetic torus which is a physical approximation to the sheared cylindrical slab. The statistical properties of the intermittency are examined through a conditional analysis of probe signal bursts and the existence of so called "blobs", coherent plasma objects which transport large amounts of particles and heat, is explored. It is shown that the conditional analysis most likely extracts artifacts due to the finite ensemble size and that no coherent part of the bursts is detected throughout the Helimak radii for all the externally applied biases. The probe signal bursts rarely follow Poisson statistics, and a match with a recently developed stochastic model based upon this is more than likely due to the large number of parameters.

关键词： Turbulence Intermittency Nuclear fusion Tokamaks Scrape-off layer blobs Filaments Plasma

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A Controlled Benchmark of Video Violence Detection Techniques

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INFORMATION 2020年第6期11卷

作者： Convertini, Nicola Dentamaro, Vincenzo Impedovo, Donato Pirlo, Giuseppe Sarcinella, Lucia Univ Bari Aldo Moro Comp Sci Dept I-70121 Bari Italy

This benchmarking study aims to examine and discuss the current state-of-the-art techniques for in-video violence detection, and also provide benchmarking results as a reference for the future accuracy baseline of violence detection systems. In this paper, the authors review 11 techniques for in-video violence detection. They re-implement five carefully chosen state-of-the-art techniques over three different and publicly available violence datasets, using several classifiers, all in the same conditions. The main contribution of this work is to compare feature-based violence detection techniques and modern deep-learning techniques, such as Inception V3.

关键词： violence video detection benchmark video violence ViF OViF MoSIFT IFV ConvLSTM Inception V3 blobs

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Performance Evaluation of Real-time and Scale-invariant LoG Operators for Text Detection 14

Performance Evaluation of Real-time and Scale-invariant LoG ...

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14th International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications (VISAPP)

作者： Dinh Cong Nguyen Delalandre, Mathieu Conte, Donatello The Anh Pham Tours Univ Tours France Hong Duc Univ Thanh Hoa Vietnam

ISBN: (纸本)9789897583544

This paper presents a state-of-the-art and a performance evaluation of real-time text detection methods, having particular focus on the family of Laplacian of Gaussian (LoG) operators with scale-invariance. The computational complexity of operators is discussed and an adaptation to text detection is obtained through the scale-space representation. In addition, a groundtruthing process and a characterization protocol are proposed, performance evaluation is driven with repeatability and processing time. The evaluation highlights a near-exact approximation with real-time operators at one to two orders of magnitude of execution time. The real-time operators are adapted to recent camera devices to process high resolution images. Perspectives are provided for operator robustness, optimization and characterization of the detection strategy.

关键词： Text Detection LoG blobs Key-points Real-time Estimators DoG Fast Gaussian Filtering Scale-space Stroke Model Groundtruthing Performance Characterization Repeatability

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A New Paradigm for Querying blobs in Vehicular Networks

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IEEE MULTIMEDIA 2014年第1期21卷 48-58页

作者： Wolfson, Ouri Xu, Bo Univ Illinois Chicago IL 60680 USA Univ Illinois Urbana IL USA Argonne Natl Lab Res & Anal Comp Ctr Argonne IL 60439 USA Univ Illinois Dept Comp Sci Chicago IL 60680 USA

A novel paradigm and several derived strategies that query binary large objects in a wireless vehicular network reveal the answer throughput and communication overhead of various approaches.

关键词： IEEE 802 11 Standards Mobile Communication Streaming Media Multimedia Communication Mobile Computing Vehicles Wireless Communication Query Processing Cellular Communication Multimedia Vehicular Ad Hoc Networks Real Time Traffic Information blobs Query Processing Mobile Peer To Peer

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Spatio-temporal elastic cuboid trajectories for efficient fight recognition using Hough forests

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MACHINE VISION AND APPLICATIONS 2018年第2期29卷 207-217页

作者： Serrano, Ismael Deniz, Oscar Bueno, Gloria Garcia-Hernando, Guillermo Kim, Tae-Kyun Univ Castilla La Mancha VISILAB Grp Ciudad Real Spain Univ Imperial Coll Dept Elect & Elect Engn London England

While action recognition has become an important line of research in computer vision, the recognition of particular events such as aggressive behaviors, or fights, has been relatively less studied. These tasks may be exceedingly useful in some video surveillance scenarios such as psychiatric centers, prisons or even in personal camera smartphones. Their potential usability has caused a surge of interest in developing fight or violence detectors. The key aspect in this case is efficiency, that is, these methods should be computationally very fast. In this paper, spatio-temporal elastic cuboid trajectories are proposed for fight recognition. This method is based on the use of blob movements to create trajectories that capture and model the different motions that are specific to a fight. The proposed method is robust to the specific shapes and positions of the individuals. Additionally, the standard Hough forests classifier is adapted in order to use it with this descriptor. This method is compared to other nine related methods on four datasets. The results show that the proposed method obtains the best accuracy for each dataset and is also computationally efficient.

关键词： Violence recognition Fight recognition Descriptor blobs Video sequences Hough forests

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Fast camera imaging of plasmas in Alcator C-Mod and W7-X

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NUCLEAR MATERIALS AND ENERGY 2018年 17卷 269-273页

作者： Ballinger, S. B. Terry, J. L. Baek, S. G. Tang, K. von Stechow, A. Killer, C. Nicolai, D. Satheeswaran, G. Drews, P. Grulke, O. MIT Plasma Sci & Fus Ctr 175 Albany St Cambridge MA 02139 USA Max Planck Inst Plasma Phys Wendelsteinstr 1 D-17491 Greifswald Germany Forschungszentrum Julich Wilhelm Johnen Str D-52428 Julich Germany

In this work we present an analysis of fast-camera imaging of Alcator C-Mod's divertor region and of the plasma cross section in the W7-X stellarator. In C-Mod, the dynamics of intermittent edge plasma filaments are imaged at 397,100 frames per second in an oblique view. An automatic pipeline was developed to reconstruct the filament motion in the R, Z plane of the divertor using EFIT field line projections. Next, we added our fast-framing camera to W7-X's diagnostic suite for the 2017 run campaign, the first with a divertor. It has a tangential view of the machine cross section, including part of a divertor module. The view is coupled to the camera via a coherent fiber bundle. The spatial resolution is 2-4 cm and the typical plasma brightness limits the fastest usable frame rate to 30k frames/s. We observe filaments in the plasma boundary that rotate around the magnetic axis during radiative collapse;filaments were observed in steady state in the limiter configuration of W7-X by Kocsis et al. [1]. We also observe for the first time a 1-2 kHz quasi-coherent fluctuation in divertor target emissions in the W7-X "standard" magnetic configuration. Finally, a rough analysis of edge gas fueling efficiency using fast camera data and S/XB coefficients finds that fueling is less efficient at densities higher than 4x10(19) m(-3).

关键词： C-Mod W7-X Filaments blobs Turbulence Fluctuation

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Remote Sensing of Mars: Detection of Impact Craters on the Mars Global Surveyor DTM by Integrating Edge- and Region-Based Algorithms

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EARTH MOON AND PLANETS 2018年第1-2期121卷 59-72页

作者： Athanassas, C. D. Vaiopoulos, A. Kolokoussis, P. Argialas, D. Natl Tech Univ Athens Sch Rural & Surveying Engn Remote Sensing Lab Athens 15780 Greece NTUA Sch Min & Met Engn Dept Geol Sci Athens 15780 Greece

This study integrates two different computer vision approaches, namely the circular Hough transform (CHT) and the determinant of Hessian (DoH), to detect automatically the largest number possible of craters of any size on the digital terrain model (DTM) generated by the Mars Global Surveyor mission. Specifically, application of the standard version of CHT to the DTM captured a great number of craters with diameter smaller than similar to 50 km only, failing to capture larger craters. On the other hand, DoH was successful in detecting craters that were undetected by CHT, but its performance was deterred by the irregularity of the topographic surface encompassed: strongly undulated and inclined (trended) topographies hindered crater detection. When run on a de-trended DTM (and keeping the topology unaltered) DoH scored higher. Current results, although not optimal, encourage combined use of CHT and DoH for routine crater detection undertakings.

关键词： Circular Hough transform Derivative of hessian blobs Computer vision Digital terrain model

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Digital Image Forensics Technique for Copy-Move Forgery Detection Using DoG and ORB

Digital Image Forensics Technique for Copy-Move Forgery Dete...

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International Conference on Computer Vision and Graphics (ICCVG)

作者： Niyishaka, Patrick Bhagvati, Chakravarthy Univ Hyderabad Hyderabad 500046 India

ISBN: (纸本)9783030006921;9783030006914

Copy-Move forgery or Cloning is image tampering or alteration by copying one area in an image and pasting it into another area of the same image. Due to the availability of powerful image editing software, the process of malicious manipulation, editing and creating fake images has been tremendously simple. Thus, there is a need of robust PBIF (Passive-Blind Image Forensics) techniques to validate the authenticity of digital images. In this paper, CMFD (Copy-Move Forgery Detection) using DoG (Difference of Gaussian) blob detector to detect regions in image, with rotation invariant and resistant to noise feature detection technique called ORB (Oriented Fast and Rotated Brief) is implemented, evaluated on different standard datasets and experimental results are presented.

关键词： blobs CMFD DoG ORB PBIF

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Segmentation and Classification of Acute Lymphoblastic Leukemia Cells Tooled with Digital Image Processing and ML Techniques 2

Segmentation and Classification of Acute Lymphoblastic Leuke...

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2nd International Conference on Intelligent Computing and Control Systems (ICICCS)

作者： Umamaheswari, D. Geetha, S. Vidyasagar Coll Arts & Sci Dept Comp Sci Udumalpet Tamil Nadu India Govt Arts Coll Dept Comp Sci Udumalpet Tamil Nadu India

ISBN: (纸本)9781538628423

Medical science has been contributing its active role in fighting vigorously against the life ceasing diseases. The algorithm is proposed by investigating the existing segmentation algorithms in the field of leukemia research for the sake of supporting hematopathologists to recognize Acute Lymphocytic Leukemia (ALL) by analyzing the blood cell images. There are four levels of separating and classifying benign and malignant white blood cells (WBC). They are, preprocessing, segmentation, extraction of features and classification. As a preliminary task of image analysis, segmentation is done with morphological operators and Otsu's thresholding. Then utilization of nucleus features with supervised KNN classifier gains the classification accuracy of 95.96%, 95.92% of sensitivity and 96% of specificity.

关键词： Acute Lymphoblastic Leukemia Morphological Operators Otsu's Thresholding Segmentation KNN Classifier blobs WBC

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Influence of molecular dissociation on blob-induced atom density perturbations

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NUCLEAR FUSION 2018年第9期58卷

作者： Thrysoe, A. S. Madsen, J. Naulin, V Rasmussen, J. Juul DTU Dept Phys PPFE DK-2800 Lyngby Denmark

The effects of enhanced electron and ion pressure perturbations mediated in filamentary structures (blobs) on the densities of neutral atoms and molecules are investigated through a self-consistent dynamical fluid model for plasma and neutral fields. The electron and ion densities and pressures, and the generalized vorticity, are simulated by a 2D drift-fluid model in an edge and scrape-off layer slab domain of a toroidaliy magnetically confined plasma. The plasma dynamics are coupled with a diffusion model for densities of neutral atoms and molecules. The combined model allows for determining the response of the density of neutrals with various temperatures to blobs. It is found that blobs locally deplete densities of molecules and atoms that do not originate from dissociation of molecules, whereas the density of atoms created by dissociation may increase during blob events. The neutral species, their temperature, and origin should thus be taken into consideration when estimating the effect of blobs on neutral density perturbations when calculating emission rates, e.g, for gas puff imaging.

关键词： edge and SOL dynamics plasma-neutral interactions gas puff imaging GPI blobs neutrals

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