基于分块和偏最小二乘的非接触式手掌静脉生物特征识别

研究了一种适用于非接触式图像采集的手掌静脉识别的子空间方法,解决了传统接触式采集容易传染疾病,非接触采集使同类图像差别增大导致识别性能不佳的问题.先采用分块算法对图像进行快速降维,再用偏最小二乘算法提取掌脉图像中灰度值变异大,且类别信息相关性最大的若干方向组成分类子空间,然后依据图像在此空间中的位置进行分类识别.应用自建掌脉图库和中科院自动化研究所图库进行实验分析,实验结果表明:与传统掌脉识别方法相比,该方法能有效地提高正确识别率,降低误拒率.两个图库中,该算法选择分块大小为4×4时的正确识别率分别达到99.98％,99.34％;误识率分别达到0.02％,0.66％;误拒率分别达到0.13％,0.60％;识别时间分别在0.03 s,0.04s之内.适用于安防、考勤等场合,具有实用价值.     

采用纹理近邻模式的掌静脉生物特征识别研究

针对传统局部二值模式(LBP)只以固定的中心像素为阈值的编码方式进行了改进,从纹理分析角度,提出一种基于近邻模式的掌脉身份识别方法,主要利用局部区域相邻像素之间的灰度大小关系,对掌脉图像进行近邻二值模式(NBP)编码。首先将手掌静脉图像分成若干大小一致的区块,然后计算每一区块的灰度平均值,形成多块均值图像,进一步使用NBP对多块均值图像进行编码,最后利用汉明距离进行匹配。采用CCD图像传感器设计了光学仪器,在实际应用环境下获取掌脉图像建立图库,并在香港理工大学(Poly U)接触式公用图库和自建非接触图库上与目前典型和流行方法进行了对比实验,结果显示该方法在8×8区块划分情况下在2个图库上获得了最低等误率(EER)分别为0.698 3%和1.603 6%,识别时间为0.122 7 s和0.124 2s,显示出方法的可行性和有效性,具有应用前景。     

基于特征参量空间的掌脉识别方法研究

非接触式采集是手掌静脉识别的主流,但其低约束性可能导致掌静脉存在平移、旋转和比例缩放,同时,手掌过度伸展可能导致部分静脉分布信息丢失,这些都可能影响掌脉识别结果.针对以上问题,提出一种新的掌静脉特征识别方法.首先,获取靠近指根部的手掌内切圆,利用内切圆内静脉交叉点和内切圆圆心定义相对半径及相邻夹角参数;其次,由相对半径和角度参数建立二维特征向量空间,将静脉交叉点转换成该特征向量空间内的一系列特征点;最后,计算特征点间的特征向量距离作为匹配点对的判断依据,根据匹配点对的比例得到匹配率.通过自建的掌静脉图库和CASIA图库对算法性能进行验证,分别得到等误率0.97％和4.98％.结果表明,该方法在手掌静脉产生比例缩放、旋转和平移后仍可获取较好的识别效果,同时具有特征点提取容错性.     

基于类卷积神经网络的可见光虹膜识别方法

针对应用于智能移动设备的虹膜识别系统在可见光采集条件下虹膜图像受干扰严重使得识别率正确率降低和算法鲁棒性变差的问题,提出一种类卷积神经网络结合局部特征提取的虹膜识别方法。首先,采用暗通道图像去雾算法对归一化虹膜图像进行增强处理以减弱光干扰;然后,利用类卷积神经网络对图像进行降维,获得虹膜的二值化纹理信息;再经分块处理方法提取降维图像各区域局部虹膜纹理信息以构建特征向量;最后用欧氏距离分类器进行匹配识别。为验证算法性能,采用MICHE-I虹膜图库中由iPhone5拍摄所得的30人240张(每人4张室内和4张室外)虹膜图像进行测试,并与Gabor变换和主成分分析虹膜识别方法进行对比。结果表明,该方法在室内外图像均进行训练的条件下正确率能够达到98.33%,且对室内外不同光照变化干扰有较好的鲁棒性,上述性能皆优于Gabor变换和PCA算法。说明本文算法能够满足移动设备虹膜识别使用要求。     

局部方向模式在非接触掌纹识别中的应用

提高非接触掌纹识别系统的性能是目前掌纹识别领域一个具有实际意义的热点。针对非接触掌纹识别系统的鲁棒性问题,以掌纹图像的纹理特征为基础,提出一种基于局部方向模式(LDP)的掌纹识别方法,设计并实现了符合应用环境的嵌入式系统。LDP方法主要利用了Kirsch八方向算子的边缘响应值,从而获取图像的纹理方向模式特征。首先给出LDP算法的基本模型和流程,然后将非接触掌纹图像分成大小均匀的区块,利用LDP算法获取不同区块的纹理特征直方图向量,并进行融合形成总的模式特征,最后使用Chi距离测度进行匹配识别。在香港科技大学(HKUST)和自建的非接触掌纹图库上进行了实验测试,结果表明,该方法正确识别率可达97.824 4%和96.754 7%,相比其他典型和流行方法,最高可提升6.452 9%和5.995 6%。同时在室内环境下,利用自行设计的嵌入式原型装置进行了初步实际测试,结果表明,该方法正确识别率可达96.193 3%,具有可行性和有效性,提高了非接触掌纹识别系统的性能。     

手形、掌纹和掌静脉多特征融合识别

单一生物特征识别技术无论是在识别率还是稳定性上都不能达到完美无缺,特别是高仿生物特征的出现使其安全性受到质疑。针对上述问题,提出一种手形、掌纹和掌静脉多特征融合识别方法。提出了基于小波变换Gabor滤波器的特征层和图像层融合策略,将同一设备不同光照采集下的掌纹和掌静脉融合到一起,突出各自的主纹理特征;利用手指相对长度为手形特征进行初匹配,提出利用分块纹理基元模型进行掌纹和掌静脉融合图像的特征提取方法,然后进行二次匹配给出最终识别结果。开发了模拟系统并进行了相应的实验,结果表明该识别系统充分发挥了3种特征各自的优点,提高了识别率和稳定性,特别是掌静脉的加入增强了系统的安全性。     

非接触式表面粗糙度识别方法的研究

提出了一种机加工纹理非接触式表面粗糙度识别的方法。该方法用纹理周期度来描述机加工纹理的表面粗糙度,通过采集表面粗糙度标准样块的图像,用图像处理方法提取相应的纹理特征值(如纹理周期度)存入数据库,再用同样的方法获取未知粗糙度等级的零件表面图像的纹理周期特征值,并与库中粗糙度标准样块图像的纹理周期特征值进行比较,按照最近似的原则得到所求表面的粗糙度。该方法识别精度较高,具有对光照条件不同的免疫力。     

基于多通道Gabor滤波与灰度梯度共生矩阵的虹膜识别方法

为有效改善虹膜识别系统的性能,针对传统方法提取全局特征时对局部纹理特征不敏感的问题,提出了一种基于多通道Gabor滤波和灰度梯度共生矩阵（GGCM）的虹膜识别方法。使用不同方向和尺度的Gabor滤波器组对预处理后的虹膜图像滤波,由全局滤波图像构建灰度梯度共生矩阵,提取特征值生成虹膜特向量。识别过程采用加权欧氏距离进行特征匹配。CASIA虹膜图像库实验表明,该方法能在保证识别系统实时性能的前提下使EER下降0.5%。     

基于局部马尔科夫模式的FPC薄浆缺陷检测

薄浆是柔性印刷电路板(FPC)导电涂层的一种缺陷,为避免其对电路性能产生不良影响而造成经济损失,检测薄浆位置从而进行修补或直接剔除板材均是合理的处理方式。FPC线路结构复杂,同时由于其线路涂层结构特性和采集环境因素影响,所获得的图像容易出现"斑点"噪声、光照不均匀等现象,这些因素导致了当前算法检测性能降低。针对该问题,提出了一种基于局部马尔科夫模式(LMP)的检测方案。首先给出LMP算法的基本模型,然后将预处理后FPC图像划分成大小均匀的区块,以降低光照影响;接着,提取各区块内部线路区域的直方图特征并以此为依据选取种子点,同时为各种子点赋予其作为缺陷的初始概率,进而计算其LMP值,并通过LMP的数值大小识别其中的薄浆缺陷像素。在自建图库SUT-F2上进行了测试,结果显示方法对薄浆缺陷检测的等误率仅为4.06%,相对于其他典型纹理特征提取和薄浆检测方法其等误率至少降低了5.14%,表明了方法的高效性,具有实际应用价值。     

基于人手自然张开的多生物特征识别

手形和掌纹作为人手重要的生物特征可以用来进行身份识别.在人手自然张开、非接触式的采集条件下,基于手形识别匹配速度快和掌纹识别的识别率高的优点,采用基于匹配层的手形和掌纹融合方法,克服了单一手形识别的识别率低和掌纹识别匹配速度慢的缺点.手形采用手指的相对长度作为特征矢量,掌纹采用2D-Gabor对掌纹感兴趣区域(ROI)进行滤波,提取掌纹纹线的方向信息作为特征.在混合图库上进行实验,二者相结合的组合识别方法的识别率达到98.57％,减少了匹配时间.同时也研究了对于不同距离采集的手掌图像,实验结果表明手形和掌纹相结合的组合识别方法优势更为明显.     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.