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随着近年来危害公共安全的群体性事件频繁发生,对人群场景下的人群状态分析与异常行为检测成为计算机视觉领域研究的热点问题。目前提出的诸如纯光流法,社会力模型,时空运动模型等算法,在检测准确率方面已能满足需求,但是算法复杂度普遍较高,运算量较大,在实际应用中难以保证实时性。鉴于此,首先,引入了人群移动区域面积的概念并定义了人群状态指数,来描述人群状态的变化,通过光流法获得人群运动矢量场,基于人群运动矢量场定义了人群运动强度指数来描述人群运动强度,基于人群运动矢量场与信息熵定义了人群混乱指数来描述人群运动方向的混乱程度。其次,基于降低算法运算量的考虑,根据上面提到的三个描述人群运动状态的特征变量设计了一种分层处理的人群异常行为检测方案,实验结果证明方案具有很好的效果。 相似文献
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群体异常行为的发生将对社会公共安全构成危害,而不同等级的群体异常行为对社会公共安全产生的危害性也不尽相同,对应的关注度和敏感度也不同,因此本文提出了一种基于人群密度的异常行为分级检测算法.首先,对现有的人群异常行为检测算法存在实时性差、检测准确度不高的问题,引入局部光流,提出了一种基于平均动能变化倍率的人群异常行为检测算法;在此基础上对现有的结合基于像素点统计和基于纹理特征的人群密度检测方法进行了改进,进而实现了基于人群密度的异常行为分级.实验证明,本文算法能够准确且稳定地检测出视频中的异常行为情况,并且能根据人群密度分级报警,满足实际应用需求. 相似文献
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针对红外序列图像中人体目标检测问题,采用了基于特征点的特征区域提取方法,先用FAST算法快速提取特征点,然后基于提取出的特征点,使用LBP算法提取特征区域,在得到感兴趣的特征区域(ROI区域)后,用对ROI区域进行基于离散小波变换的小波熵特征提取,并采用复合分类方法对ROI区域进行分类,利用此方法有效地将人体目标从红外序列图像中检测出来。 相似文献
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采用序列模式挖掘算法构建电网异常检测模型,能够更好地表现电网异常行为。基于此进行了电网异常检测建模方法的研究,并提出了一个基于模糊序列模式的电网异常检测模型。通过理论分析和仿真实验证明,提出的模型不仅具有检测异常行为的实际能力,而且检测效率和检测性能都得到了很大的提高。 相似文献
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实现电磁数据的异常检测和模式发现,对电磁目标异常行为的判断与提前预警具有重要价值。不同类型的电磁数据通常以时间序列的形式存在,且具有正常数据与异常数据不均衡等特点。为应对上述挑战,提出一种基于时空联合注意力机制的时间序列异常检测方法。基于电磁数据的时间与空间特征,结合通道与空间注意力机制,增强对时序数据异常部分的特征表示。实验结果表明,提出的检测算法能够有效应对数据不均衡的难点,具有较强的鲁棒性。 相似文献
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针对骨架行为识别对时空特征提取不充分以及难以捕捉全局上下文信息的问题,研究了一种将时空注意力机制和自适应图卷积网络相结合的人体骨架行为识别方案。首先,构建基于非局部操作的时空注意力模块,辅助模型关注骨架序列中最具判别性的帧和区域;其次,利用高斯嵌入函数和轻量级卷积神经网络的特征学习能力,并考虑人体先验知识在不同时期的影响,构建自适应图卷积网络;最后,将自适应图卷积网络作为基本框架,并嵌入时空注意力模块,与关节信息、骨骼信息以及各自的运动信息构建双流融合模型。该算法在NTU RGB+D数据集的两种评价标准下分别达到了90.2%和96.2%的准确率,在大规模的数据集Kinetics上体现出模型的通用性,验证了该算法在提取时空特征和捕捉全局上下文信息上的优越性。 相似文献
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针对人群异常行为检测任务中存在的算法复杂度较高,重叠遮挡等带来的检测精度低等问题,本文提出一种基于改进SSD(Single Shot Multi-box Detector)的人群异常行为检测算法。首先采用轻量级网络MobileNet v2代替原始特征提取网络VGG-16,并通过可变形卷积模块构建卷积层来增强感受野,然后通过将位置信息整合到通道注意力中来进行特征增强,能够捕获空间位置之间的远程依赖关系,从而可以较好处理重叠遮挡问题。实验结果表明,本文提出的算法对人群异常行为具有较好的检测效果。 相似文献
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Zheyi Fan Jiao Jiang Shuqin Weng Zhonghang He Zhiwen Liu 《Journal of Signal Processing Systems》2018,90(12):1651-1666
In order to obtain effective crowd relationships for crowd behavior analysis, an adaptive crowd segmentation method based on coherent motion detection is proposed. This method can improve the accuracy of segmentation results and be adaptively applied to various collective scenes that have different distributions at different scales. Firstly, an orientation clustering algorithm and a spatial joint strategy are proposed to preliminarily profile all agents into several partitions with different motion orientations. Then, the Natural Nearest Neighbor algorithm is introduced to construct the adaptive crowd motion networks combining with the profiling results, which can describe the neighborhood relationships of agents with stronger coherence. Finally, the improved Coherent Neighbor Invariance optimized by fusing motion information of neighbors is proposed to segment crowds with coherent motions from the crowd motion networks. The experiment results on videos depicting real-world crowd scenes indicate that the proposed method is effective and adaptive to various scenes. 相似文献
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基于OpenCV与混合高斯建模的运动目标检测 总被引:1,自引:0,他引:1
针对静态背景下的视频运动序列,在研究现有的检测算法——帧间差分法与背景差分法的基础上,进一步研究了运动目标检测中背景动态建模的方法——混合高斯建模法,在此基础上提出了基于混合高斯模型与三帧差分的运动目标检测改进算法。由于使用背景差分法检测运动目标时,运动物体和阴影都将被看作运动的目标,于是研究了基于归一化RGB色彩模型的阴影处理方法,对阴影区域进行检测与去除。然后使用计算机视觉类库OpenCV结合Visual C++6.0对上述算法进行实现,取得了很好的检测效果。 相似文献
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Nan Zhang Xiaolong Yang Min Zhang Yan Sun Keping Long 《International Journal of Communication Systems》2018,31(1)
With the rapid development of cloud computing, the number of cloud users is growing exponentially. Data centers have come under great pressure, and the problem of power consumption has become increasingly prominent. However, many idle resources that are geographically distributed in the network can be used as resource providers for cloud tasks. These distributed resources may not be able to support the resource‐intensive applications alone because of their limited capacity; however, the capacity will be considerably increased if they can cooperate with each other and share resources. Therefore, in this paper, a new resource‐providing model called “crowd‐funding” is proposed. In the crowd‐funding model, idle resources can be collected to form a virtual resource pool for providing cloud services. Based on this model, a new task scheduling algorithm is proposed, RC‐GA (genetic algorithm for task scheduling based on a resource crowd‐funding model). For crowd‐funding, the resources come from different heterogeneous devices, so the resource stability should be considered different. The scheduling targets of the RC‐GA are designed to increase the stability of task execution and reduce power consumption at the same time. In addition, to reduce random errors in the evolution process, the roulette wheel selection operator of the genetic algorithm is improved. The experiment shows that the RC‐GA can achieve good results. 相似文献
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Fast XYT imaging of elementary calcium release events in muscle with multifocal multiphoton microscopy and wavelet denoising and detection 总被引:1,自引:0,他引:1
We used multifocal multiphoton microscopy to image fast, localized elevations of the cytosolic Ca2+ concentration in two spatial dimensions plus time (XYT). This technique extends the common spatially 1-D XT imaging and allows the acquisition of more than ten times longer time series (>500 images) and ten times larger areas of interest than for previously used confocal XYT imaging techniques due to lower phototoxicity and fast multifocal scanning. We recorded spontaneously occurring elementary Ca2+ release events in chemically permeabilized adult mammalian skeletal muscle fibers using two-photon excitation of the fluorescent dye Fluo-4. The resulting time series were analyzed with an automated denoising and detection algorithm based on the à trous implementation of the discrete wavelet transform. Wavelet coefficient hard-thresholding is used for denoising and event detection is performed across several wavelet scales. The spatiotemporal characteristics of the detected Ca2+ release events are followed throughout the XYT stack and are parametrized using a biophysically valid anisotropic Gaussian event model. The proposed method allows a detailed spatiotemporal analysis of elementary Ca2+ release events underlying the excitation-contraction coupling process in muscle. 相似文献