Algorithm based on morphological component analysis and scale-invariant feature transform for image registration

In this paper, we proposed a registration method by combining the morphological component analysis (MCA) and scale-invariant feature transform (SIFT) algorithm. This method uses the perception dictionaries, and combines the Basis-Pursuit algorithm and the Total-Variation regularization scheme to extract the cartoon part containing basic geometrical information from the original image, and is stable and unsusceptible to noise interference. Then a smaller number of the distinctive key points will be obtained by using the SIFT algorithm based on the cartoon part of the original image. Matching the key points by the constrained Euclidean distance, we will obtain a more correct and robust matching result. The experimental results show that the geometrical transform parameters inferred by the matched key points based on MCA+SIFT registration method are more exact than the ones based on the direct SIFT algorithm.     

一种改进的SIFT图像立体匹配算法

针对SIFT算法复杂度高、计算时间长、影响立体匹配的实时性等问题,提出了一种改进的立体视觉特征点匹配算法该算法从两个方面对SIFT算法进行改进:首先利用24维特征描述符代替128维特征描述符,以降低计算复杂度;其次在图像对匹配过程中采用改进的BBF搜索算法,通过引入最小优先级队列的限制条件和匹配精度更高的马氏距离判断两幅图像特征点的匹配性.采用经典图像和未知的室外环境下拍摄的图像对本文算法进行实验验证,结果表明,本文提出的算法每100个特征点检测时间为0.01 s,正确匹配率平均为89.65%,相对于原算法,提高了匹配的准确度,并降低了匹配时间.      

Calculation of strain amplification matrix for strain invariant failure theory based on representative volume element models with periodical boundary condition

Strain invariant failure theory (SIFT) is a micro-mechanics-based failure theory for multi-scale failure analysis of composite materials originally proposed by Gosse and Christensen. In this paper, the approach for obtaining strain amplification matrix which is a key step for the execution of SIFT is improved by adopting representative volume element (RVE) finite element models considering periodical boundary condition, based on which more actual deformation mode is reflected. The deformation modes and strain data at the characteristic points of the centroid cell of multi-cell RVE model are analyzed and taken as a reference. It can be concluded that more reasonable deformation mode and relationship between the micro-mechanical and macro-mechanical strain states are obtained by employing the new model. Finally, numerical examples are provided to illustrate the determination of strain amplification factors within the RVEs considering periodical boundary condition at the characteristic points.     

基于点特征和边缘特征的无人机影像配准方法

为解决变形较大的无人机影像配准问题,提出了点特征和边缘特征相结合的配准方法.用尺度不变特征变换(SIFT)算法提取点特征,完成影像的初步配准,并通过多项式函数对影像进行粗校正.在此基础上提取影像的边缘特征信息,根据距离相似性对边缘特征信息进行配准;依据色彩能量差筛选点特征信息配准结果和边缘特征信息配准结果,采用小面元微分校正的方法对变形影像进行校正.实验结果表明:提出的配准方法能够弥补点特征配准方法和边缘特征配准方法的不足,其配准的鲁棒性提高10%左右,可以较好地完成变形较大的无人机影像配准.      

复杂环境基于多信息融合的车辆跟踪方法

平交路口复杂环境下基于视觉的车辆跟踪容易受到如车辆在图像上投影的尺 度变化,车辆的排队与消散过程中邻近车辆间的遮挡及分离等因素的影响.针对该问题, 本文提出了一种利用局部特征增强的Mean-shift 改进算法,利用SIFT 特征点对尺度、旋 转变化鲁棒的特性,将其与基于跟踪区域颜色特征的跟踪方法相融合实现车辆跟踪,较 好地解决了在车辆尺度、运动方向变化,以及遮挡情况下的跟踪问题.同时通过引入跟踪 车辆分离的判定条件,结合特征点聚类算法解决了相邻车辆发生分离时的判断及跟踪问 题.实验结果表明,在多种交通场景的车辆跟踪过程中,本文提出的算法有较好的鲁棒性, 定位结果更加精确.     

彩色图像中基于几何不变性的数字水印

常规的数字水印算法对几何攻击无能为力,水印算法对几何攻击的鲁棒性被认为是数字水印技术走上实际应用的一个关键点.文中通过对普通的基于几何不变性数字水印算法的分析,提出了一种彩色图像中基于几何不变性的数字水印的嵌入及检测过程,并通过一系列实验证明了该数字水印算法具有很高的抗几何攻击(旋转、缩放等)特性,即提高了鲁棒性.     

Mobile Robot Hierarchical Simultaneous Localization and Mapping Using Monocular Vision

A hierarchical mobile robot simultaneous localization and mapping (SLAM) method that allows us to obtain accurate maps was presented. The local map level is composed of a set of local metric feature maps that are guaranteed to be statistically independent. The global level is a topological graph whose arcs are labeled with the relative location between local maps. An estimation of these relative locations is maintained with local map alignment algorithm, and more accurate estimation is calculated through a global minimization procedure using the loop closure constraint. The local map is built with Rao-Blackwellised particle filter (RBPF), where the particle filter is used to extending the path posterior by sampling new poses. The landmark position estimation and update is implemented through extended Kalman filter (EKF). Monocular vision mounted on the robot tracks the 3D natural point landmarks, which are structured with matching scale invariant feature transform (SIFT) feature pairs. The matching for multi-dimension SIFT features is implemented with a KD-tree in the time cost of O(lbN). Experiment results on Pioneer mobile robot in a real indoor environment show the superior performance of our proposed method.     

基于混沌遗传算法的基元提取

提出了一种直接在灰度图像上进行基元提取的方法．与传统基元提取方法相比，该方法不需对灰度图像进行边缘检测二值化处理，而是利用图像边缘的梯度信息对混沌遗传算法导向，直接在灰度图像上提取基元．同时，该方法也避免了Hough变换高的时空开销问题．仿真表明该方法方便、有效并具有较高稳定性．     

基于DCT-SVD的抗几何攻击图像水印算法

针对DCT域的最优均值量化盲水印算法抵抗剪切、旋转、缩放等几何攻击的能力不强,给出了一种DCT-SVD图像水印算法.该算法利用奇异值具有几何不变性,使算法具有较好抗几何攻击性能.实验结果表明,该算法对加噪、JPEG压缩、滤波、几何攻击等多种攻击都具有很强的鲁棒性.     

应用改进的稳健设计法分析梁柱外节点抗剪强度

介绍了改进的稳健设计法,并引入新的信噪比,考虑的因素包括混凝土强度、水平箍筋屈服强度和竖向箍筋屈服强度.用软化桁架模型分析梁柱外节点抗剪强度,并应用改进的稳健设计法对影响梁柱外节点抗剪强度的因素进行分析,得出了各种影响因素的重要程度,与田口方法相比改进的稳健设计法的分析结果与试验结果吻合较好,应用更加准确、方便.     

一种改进型自抗扰控制器在船舶电力推进中的应用

为了解决船舶电力推进中转子磁场定向矢量控制定子电压方程中耦合项的影响,获得更好的动态性能和鲁棒性,本文提出了一种改进型自抗扰控制器,对自抗控制器典型结构做了一定的简化,并将其应用于船舶电力推进中的异步电机转子磁场定向矢量控制,实现了船舶电力推进中的异步电机磁链和转矩的快速调节。仿真结果表明,该控制系统具有优异的动态控制性能,而且参数鲁棒性较强。     

Wavelet Transform Modulus Maxima-Based Robust Digital Image Watermarking in Wavelet Domain

A new robust watermarking approach was proposed in 2D continuous wavelet domain (CWT).The watermark is embedded into the large coefficients in the middle band of wavelet transform modulus maxima (WTMM) of the host image.After possible attacks,the watermark is then detected and extracted by correlation analysis.Compared with other wavelet domain watermarking approaches,the WTMM approach can endow the image with both rotation and shift invariant properties.On the other hand,scale invariance is achieved with the geometric normalization during watermark detection.Case studies involve various attacks such as shifting,lossy compression,scaling,rotation and median filtering on the watermarked image,and the result shows that the approach is robust to these attacks.     

导航电子地图中道路网增量信息的多尺度探测

针对常用增量信息提取方法中根据经验阈值确定新旧目标匹配的不足,提出一种导航电子地图中道路网增量信息的多尺度探测方法.该方法用最大类间方差法自适应地确定几何匹配阈值来探测增量信息,完善了基于道路网眼密度的增量变化目标渐进式选取算法,实现了增量信息在较小比例尺下的缩编提取.增量信息探测实验研究结果表明:基于自适应匹配阈值的新旧版本对应路网目标匹配准确率达到了90%,优于传统的经验阈值匹配精度;改进的增量变化目标渐进式选取算法可以满足路网增量更新的结构选取需求.      

一种基于几何约束的轨道提取方法研究

针对基于Hough变换或螺旋曲线模型的视觉轨道检测方法存在的不足,本文提出了一种基于几何约束的轨道提取方法.该方法利用摄像机和轨道平面之间的成像关系近似满足单因矩阵的特点,利用逆透视映射(IPM)将输入图像转换为Bird-view图像,并采用一种改进的边缘检测方法进行边缘检测.然后将二值化的边缘图像在垂直方向上分割为多个区段,在每个区段上,利用先验知识生成的系列模板图像,对分段IPM图像进行去噪处理和Chamfer距离变换后进行距离匹配检测,将轨道检测转换为一个二维匹配搜索过程.在分段检测结果的基础上,进一步利用曲线拟合得到边缘图像中完整的轨道曲线方程.该曲线方程通过已知的单因矩阵转换为原始图像中的曲线描述,实现在原始图像中的检测和定位.实验验证了所提方法的可行性和可靠性.     

Weld Models Incorporating the HAZ Phase Transformation Effects, Comparison between Experimental and Numerical Results

lIntroductionEleCtricit6deFrance,Framatomeandbureaudecontr6ledeschaudi6resnucl6aires,hadledaresearchprogramonweldingfinitO-elemotsimulatonforthedsterminatonofnuclearcomPonensresidualstressesandinparticuarforsomesteelwithmetallurgicaltransformations.OneofthemainstagesofthswOrkistovalidatethemechancalmodelsimPlatedinfinite-elemotcodeswithinwhichthemetallurgicaltransformationseffectsareincorporated.ThisisthepurposeofthePresentpaper.ThetWocodesusedhereareSysweld(Framatome)andCOdeAster(EDF).…     

KS函数在控制曲面中的应用

为了使控制器既能具备鲁棒与非线性特性,又保持传统PID控制器的优势,拟采用基于神经元嵌入模糊控制表的阵列式非线性控制器．采用一种新的方法,将计算机辅助几何设计领域中,基于KS函数凝聚算法的三维几何外形磨光方法应用到控制曲面光滑拟合中,为子控制器的平滑转换与控制器参数自调整算法收敛提供了保证．     

基于几何一致性指数的判断矩阵一致性改进

针对现有一致性改进方法中存在的缺陷，用行几何平均法和几何一致性指数分别作为确定权重的方法和一致性检验的标准，根据可能满意度原理，定义了一致可信度，作为判断矩阵一致性改进的标准．在此基础上。提出了新的一致性改进方法．算例分析表明该方法解决了原有改进标准不合理的问题，所得的最佳改进判断矩阵在一致性得到改进的同时，最大程度地保留了决策者的原始偏好信息．     

自研发微晶蜡类温拌改性剂微观性能试验研究

借助微观试验对以费托蜡为主要原料的自主研发微晶蜡类温拌沥青改性剂性能进行评价,通过气相色谱、差热分析、红外光谱等微观试验表明,自研发温拌改性剂分子结构、化学组成和纯度较好;温拌改性沥青的基本性能试验与SHRP性能试验表明,相较于基质沥青,温拌沥青高温粘度降低,软化点显著提高,并使基质沥青提高了一个高温PG等级,说明自主研发的温拌改性剂具有较好的降粘与提高高温性能的功能。     

A robust decision feedback equalizer for ATSC DTV receivers

Least mean square （LMS） decision feedback equalizer （DFE） is preferred as an effective solution to coping with inter-symbol interference （ISI） for ATSC digital television （DTV） receivers. In DTV transmission environment, echo delay often covers several hundreds symbols, which leads to very large-scale equalizer. One consequence of the large-scale equalizer is the very slow convergence, which combined with error propagation, inherent drawback of DFE, seriously deteriorates the performance of the receivers, especially in severe channels. More working modes and corresponding robust control mechanism were given to help the equalizer converge to the stable state smoothly. Simulation results show that the improved equalizer can perform better, especially in the severe channels.