基于深度学习的视频中人体动作识别进展综述

视频中的人体动作识别是计算机视觉领域内一个充满挑战的课题.不论是在视频信息检索、日常生活安全、公共视频监控,还是人机交互、科学认知等领域都有广泛的应用.本文首先简单介绍了动作识别的研究背景、意义及其难点,接着从模型输入信号的类型和数量、是否结合了传统特征提取方法、模型预训练三个维度详细综述了基于深度学习的动作识别方法,及比较分析了它们在UCF101和HMDB51这两个数据集上的识别效果.最后分别从视频预处理、视频中人体运动信息表征、模型学习训练这三个角度对未来动作识别可能的发展方向进行了论述.     

基于行为模式树的人体动作识别

本文选用3D卷积神经网络提取特征,并提出了一种基于数据挖掘的模型——行为模式树(Action Pattern Tree,APTree),通过分析动作模式,并对动作分类进行二次概率估计来获得更高的识别率。该模型充分考虑到视频中动作的时序性,能够对一段动作进行时间和空间上的建模。行为模式树基于数据挖掘,用于视频的动作识别,简单、紧凑而又高效。本文在UCF101数据集上进行实验并取得了87.13%的准确率,证明了行为模式树的有效性。     

基于图像识别的中老年人下肢动作运动参数提取方法研究

针对传统的运动参数提取方法一直存在提取误差大、耗时长的问题,提出基于图像识别技术的中老年人下肢动作运动图像参数提取方法,使人体运动行为识别能力得到提升。首先,结合中老年人下肢运动速度特征和三维运动形状的时空梯度自相关特征,计算出边缘梯度方向空间分布与梯度之间的自相关性,将时空自相关特征与视频运动特征相结合,使特征识别具备相应的数据条件;其次,人体下肢动作的视频图像数据是典型的时间序列数据,因此,基于人体骨架局部特征,利用训练数据能够构造完备字典,完成数据编码,运用时域金字塔匹配法对编码后的向量进行下肢动作运动图像特征参数提取与识别。实验结果证明,利用基于图像识别技术对中老年人下肢动作运动图像参数实现了准确有效的提取。     

引入高阶注意力机制的人体行为识别

现有的视频行为识别方法在特征提取过程中,存在忽略各个特征之间相互作用关系的问题,对近似动作的区分效果不理想。因此,提出引入高阶注意力机制的人体行为识别方法。在深度卷积神经网络中引入高阶注意力模块,通过注意力机制建模和利用复杂和高阶的统计信息,对训练过程中特征图各个部分的权重进行重新分配,从而关注局部细粒度信息,产生有区别性的关注建议,捕获行为之间的细微差异。在UCF101和HMDB51这两个人体行为数据集上的实验结果表明,与现有方法相比,识别率得到了一定的提升,验证了所提出方法的有效性和鲁棒性,提高了对近似行为的辨别能力。      

结合时序动态图和双流卷积网络的人体行为识别

为了更好地对人体动作的长时时域信息进行建模,提出了一种结合时序动态图和双流卷积网络的人体行为识别算法。首先,利用双向顺序池化算法来构建时序动态图,实现视频从三维空间到二维空间的映射,用来提取动作的表观和长时时序信息;然后提出了基于inceptionV3的双流卷积网络,包含表观及长时运动流和短时运动流,分别以时序动态图和堆叠的光流帧序列作为输入,且结合数据增强、模态预训练、稀疏采样等方式;最后将各支流输出的类别判定分数通过平均池化的方式进行分数融合。在UCF101和HMDB51数据集的实验结果表明:与传统双流卷积网络相比,该方法可以有效利用动作的时空信息,识别率得到较大的提升,具有有效性和鲁棒性。     

浅谈基于内容的视频检索关键技术及应用

随着多媒体数据压缩、存储与传输技术的进步,越来越多的人能够更加方便、经济的获取到大量数字视频。人们面临的问题不再是缺少多媒体内容,而是如何在浩如烟海的多媒体世界中找到自己所需要的信息。为能够方便人们寻找视频数据,基于内容的视频检索（CBVR,Content—based Video Retrieval）技术引起了人们广泛的关注。     

基于人体关节点的行为识别算法研究

针对目前大多数行为识别算法可识别动作单一且复杂背景下准确性较低的问题,提出一种基于关节点的行为识别方法,首先,使用多目标跟踪模型FairMot将视频中的人体用矩形框标记,然后再使用姿态估计模型AlphaPose模型估计视频中人物的骨骼关节点位置,同时将人物关节点数据进行组合,使其能够代表动作特征,最后,利用长短期记忆网络将组合出的动作特征序列作为输入进行识别,最终输出为某一具体动作。实验结果表明,直接对人物关节点进行动作识别,去除了背景等干扰,识别的准确率达到了91.73%,实现了特定场景下的行为识别。     

一种基于SVM主动学习的卡通视频检测方法

通过分析卡通与非卡通视频在视觉上的差异,对视频片断提取了MPEG-7描述子等8组视觉特征来构造卡通视频的特征空间;并将主动相关反馈技术引入到支撑向量机(SVM)算法中,设计了一种基于主动学习的卡通视频检测分类方法。利用大量实际视频片断所做的测试实验结果表明,该文选取的特征对卡通和非卡通视频有较好的区分能力;且与单纯的SVM算法以及传统相关反馈和SVM算法结合的方法相比,该文算法在检测性能上有较大的优势。     

基于智能感知的人体跌倒动作识别技术研究

为提高跌倒动作的正确识别次数,提出基于智能感知的人体跌倒动作识别技术.采集人体运动行为数据,保证数据识别的真实有效性;提取跌倒动作特征,提高动作识别效果;基于智能感知识别跌倒行为,减少伪跌倒动作的识别影响;由此实现人体跌倒动作的实时分析.采用对比实验的方式,验证新识别技术的识别效果更佳,具有一定的推广价值.     

融入注意力机制的深度学习动作识别

针对现有的深度学习方法在人体动作识别中易出现过拟合、易受到干扰信息影响、特征表达能力不足的问题,提出了一种融入注意力机制的深度学习动作识别方法.该方法在数据预处理中提出了视频数据增强算法,降低了模型过拟合的风险,然后在视频帧采样过程中对现有的采样算法进行了改进,有效抑制了干扰信息的影响,并在特征提取部分提出了融入注意力的残差网络,提高了模型的特征提取能力;之后,利用长短时记忆(Long Short-Term Memory,LSTM)网络解决了空间特征的时序关联问题;最后,通过Softmax完成了相应动作的分类.实验结果表明,在UCF YouTube、KTH和HMDB-51数据集上,所提方法的识别率分别为96.72％、98.06％和64.81％.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.