新型混沌粒子群算法在PCB电路检测中应用

传统的粒子群优化算法(PSO)基于粒子的搜索向最优方向逼近,在解决复杂的多峰函数的优化问题时容易陷入局部极值点,得不到正确的优化结果.为此研究能够优化多峰函数的新型粒子群优化算法.将混沌的概念和子种群的概念引入粒子群优化算法,从而形成一种新型的基于子种群的混沌粒子群优化算法,用以解决多峰值优化问题.这种新型的优化算法应用于PCB电路板的模块匹配问题,通过实验研究验证了它的有效性.算法能够识别并准确找到电阻元件,并检测出焊错的原件.该优化方法适用于过程优化、模式识别、图像检测等复杂的工程优化问题.     

匹配与姿态估计的粒子群优化算法

点模式匹配问题是机器视觉与模式识别领域中一个基础问题,在目标识别、医学图像配准、遥感图像匹配、姿态估计等方面都得到广泛应用。提出一种在仿射变换下利用粒子群优化算法进行图像点模式下的匹配与姿态估计的方法。算法首先把点集匹配问题转化为解空间为仿射参数空间下的目标函数优化问题,然后运用粒子群算法对相应的变换参数进行搜索,获得问题最优解。本文贡献如下：1)给出一种仿射参数的初始估计方法,提高了后续算法搜索效率;2)引入阈值和次近点规则,改进了最近点匹配搜索方法,能较好地拒绝出格点（outliers）,并提高算法有效性;3)从两方面对PSO方法进行了改进,加强了原PSO的全局和局部搜索能力。实验结果表明,算法具有有效性和鲁棒性。     

基于自适应稀疏分解的声音识别算法

针对公共环境中异常声音的检测与识别存在的强噪声干扰及检测效率低的问题,提出基于参数自适应匹配跟踪的声信号识别算法.基于粒子和种群的进化率改进粒子群参数的自适应设置并优化稀疏分解目标函数;基于自适应粒子群算法的连续集搜索特性建立连续超完备Gabor原子集,以提高最匹配优原子与声信号的匹配度并加速原子的匹配搜索;使用SVM分类器实现公共环境异常声信号的复合特征识别.实验结果表明,与已有算法相比,该算法的公共环境异常声信号的识别率最优,且对不同背景噪声具有较好的识别鲁棒性.     

基于确定性退火技术的鲁棒性的点匹配算法

点匹配问题一直是计算机视觉和模式识别领域的一项重要的基础性工作，该文提出了一种基于确定性退火技术的准确，快速和鲁棒性的点匹配方法，该方法首先确定在一一对应双向约束的点匹配问题的自由能函数，通过最小化该能量函数可以同时得到点集之间的匹配矩阵和映射参数，由于将匹配矩阵的估计嵌入到确定性退火算法的框架下，利用退火温度来控制匹配矩阵的模糊度，不仅增强了算法的鲁棒性，而且减小了陷入局部极小的可能性，另外，在该算法中通过引入松驰变量，可以鲁棒性地处理出格点（outliers)，实验结果验证了该算法的有效性和鲁棒性。     

基于仿射参数估计的迭代点匹配算法

本文提出了一种新的迭代点匹配算法。算法建立点集间仿射映射关系，把匹配问题转化为函数优化问题，通过点集间匹配对应关系和仿射变换参数的反复迭代最终求出问题的解。文中提出了构造虚拟点对和最小方差两种仿射参数估计方法，并利用改进最近点原则求解点集匹配关系，且证明了算法的收敛性。本文算法较好地解决了由仿射带来的非刚性形变点集匹配问题，且有很好的抗噪声和点性能。实验证明了算法的有效性和鲁棒性。     

一种改进的混沌量子粒子群优化算法

通过将量子粒子群优化算法和佳点集法相结合,提出一种改进的混沌量子粒子群优化算法,用于解决复杂函数问题。将佳点集融合到量子粒子群算法中,以提高解空间的遍历性,对函数实现全局寻优。用混沌序列改变惯性权重 w,调节粒子群优化算法的全局和局部寻优能力。采用线性递减速度比例收缩因子η提高搜索速度,避免早熟收敛。用量子Hadamard门对量子编码进行变异,增强种群的多样性,促使粒子跳出局部极值点。对典型复杂函数的仿真结果表明,该混合算法寻优效率高、收敛速度快,能有效避免早熟收敛。     

具有主从结构的粒子群优化算法

提出了一种具有主从结构的粒子群优化算法,该算法实现了惯性权重、加速因子、最大速度等系统参数与目标函数的同步优化。将主程序的一个粒子作为子程序的一组系统参数,在该组控制参数下使用基本的粒子群算法对子程序的目标函数进行优化,并把子程序优化所得的全局最优值返回主程序作为主程序的一个适应值,同时使用基本的粒子群算法对主程序的适应度函数进行优化。实验结果表明,该算法的优化性能较基本的粒子群算法有了显著提高。该方法对于粒子群算法的参数选择具有指导意义。     

基于引力模型的三维运动点集的非精确匹配

本文提出了一种基于引力模型(attractive model)的非精确匹配算法,应用于三维空间运动点集的对应点匹配问题.根据引力模型,我们将匹配和运动估计问题转化为一个代价函数的全局优化问题,实现了无对应点的运动估计和总体匹配.这种算法是一个鲁棒(robust)估计和匹配方法,可以处理包含非匹配点对的三维运动点集.大量计算机模拟实验结果充分证明了算法的鲁棒性和有效性.     

基于动态参数优化的混沌粒子群算法

针对传统粒子群优化算法易陷入局部极值点的问题,将混沌运动的遍历性,随机性以及初值敏感性等特点融入粒子群优化过程中,并通过模拟退火的方法对参数实现局部优化,使得粒子群优化算法的参数随着优化算法的进行不断改变,以适应不断变化的优化需要.通过对经典函数的仿真实验,证明了该方法在提高收敛性的前提下,收敛精度较传统算法也有了提高,且克服了易陷入局部极值区域的问题.     

基于线性规划和相似变换的点匹配算法

为解决点匹配过程中非刚性形变、位置噪声和出格点等因素导致点匹配不理想的问题,提出一种基于线性规划和相似变换的特征点匹配算法。点匹配被建模成一个能量函数最小化问题。在该函数中,形状上下文特征用于降低点对应关系的歧义性,相似变换用于保持空间映射的连续性,连续松弛问题归结为一个线性规划。仿真结果证实了该算法的有效性。     

Correspondence matching using kernel principal components analysis and label consistency constraints

This paper investigates spectral approaches to the problem of point pattern matching. We make two contributions. First, we consider rigid point-set alignment. Here we show how kernel principal components analysis (kernel PCA) can be effectively used for solving the rigid point correspondence matching problem when the point-sets are subject to outliers and random position jitter. Specifically, we show how the point- proximity matrix can be kernelised, and spectral correspondence matching transformed into one of kernel PCA. Second, we turn our attention to the matching of articulated point-sets. Here we show label consistency constraints can be incorporated into definition of the point proximity matrix. The new methods are compared to those of Shapiro and Brady and Scott and Longuet-Higgins, together with multidimensional scaling. We provide experiments on both synthetic data and real world data.     

Affine invariant comparison of point-sets using convex hulls and hausdorff distances

Many object recognition or identification applications involve comparing features associated with point-sets. This paper presents an affine invariant point-set matching technique which measures the similarity between two point-sets by embedding them into an affine invariant feature space. The developed technique assumes no a priori knowledge of reference points, as is the case in many identification problems. Reference points of a point-set are obtained based on its convex hull. An enhanced version of the Modified Hausdorff Distance is also introduced and used in the feature space for comparing two point-sets. It should be noted that the technique does not attempt to obtain correspondences between the point-sets. The introduced technique is applied to two real databases and its performance is found favorable as compared to three other affine invariant matching techniques.     

Correspondence matching with modal clusters

The modal correspondence method of Shapiro and Brady aims to match point-sets by comparing the eigenvectors of a pairwise point proximity matrix. Although elegant by means of its matrix representation, the method is notoriously susceptible to differences in the relational structure of the point-sets under consideration. In this paper, we demonstrate how the method can be rendered robust to structural differences by adopting a hierarchical approach. To do this, we place the modal matching problem in a probabilistic setting in which the correspondences between pairwise clusters can be used to constrain the individual point correspondences. We demonstrate the utility of the method on a number of synthetic and real-world point-pattern matching problems.     

Spectral correspondence for point pattern matching

This paper investigates the correspondence matching of point-sets using spectral graph analysis. In particular, we are interested in the problem of how the modal analysis of point-sets can be rendered robust to contamination and drop-out. We make three contributions. First, we show how the modal structure of point-sets can be embedded within the framework of the EM algorithm. Second, we present several methods for computing the probabilities of point correspondences from the modes of the point proximity matrix. Third, we consider alternatives to the Gaussian proximity matrix. We evaluate the new method on both synthetic and real-world data. Here we show that the method can be used to compute useful correspondences even when the level of point contamination is as large as 50%. We also provide some examples on deformed point-set tracking.     

Similarity K-d tree method for sparse point pattern matching with underlying non-rigidity

We propose a method for matching non-affinely related sparse model and data point-sets of identical cardinality, similar spatial distribution and orientation. To establish a one-to-one match, we introduce a new similarity K-dimensional tree. We construct the tree for the model set using spatial sparsity priority order. A corresponding tree for the data set is then constructed, following the sparsity information embedded in the model tree. A matching sequence between the two point sets is generated by traversing the identically structured trees. Experiments on synthetic and real data confirm that this method is applicable to robust spatial matching of sparse point-sets under moderate non-rigid distortion and arbitrary scaling, thus contributing to non-rigid point-pattern matching.     

Unsupervised learning of an atlas from unlabeled point-sets

One of the key challenges in deformable shape modeling is the problem of estimating a meaningful average or mean shape from a set of unlabeled shapes. We present a new joint clustering and matching algorithm that is capable of computing such a mean shape from multiple shape samples which are represented by unlabeled point-sets. An iterative bootstrap process is used wherein multiple shape sample point-sets are nonrigidly deformed to the emerging mean shape, with subsequent estimation of the mean shape based on these nonrigid alignments. The process is entirely symmetric with no bias toward any of the original shape sample point-sets. We believe that this method can be especially useful for creating atlases of various shapes present in medical images. We have applied the method to create mean shapes from nine hand-segmented 2D corpus callosum data sets and 10 hippocampal 3D point-sets.     

一种鲁棒的指纹细节特征点匹配方法

指纹细节特征点匹配是指纹识别过程的核心部分,鲁棒的细节特征点匹配方法需要克服指纹的旋转、变形和真实特征点丢失的情况。该文通过引入支持模型来进行细节特征点匹配,获得了较好的结果。在对支持模型理论进行简单分析之后,详细介绍了所提出的一个鲁棒的基于支持模型的细节特征点匹配算法。该方法通过融合多个种子松弛匹配的结果,来获取每个细节特征点的约束支持。并通过每个对应点不同的支持度得到一一对应的细节特征点匹配结果。最后给出两个指纹细节特征点集的相似性水平。该算法具有较强的鲁棒性和稳定性,能够很好地解决指纹细节特征点匹配过程中存在的旋转、变形和真实细节特征点丢失等情况。最后给出的实验结果验证了该算法的有效性。     

基于最大熵和互信息最大化的特征点配准算法

点配准问题在机器视觉、医学图像等领域，有着非常重要的应用基础．通过在最大化熵原理的基础上，将互信息相似性测度引入到点配准算法中，提出了一种新的快速、准确的健壮性的点配准算法．首先建立起表示两个特征点集之间匹配对应关系的联合概率分布匹配矩阵，通过最大化熵和互信息最大化，建立起一个包含匹配矩阵和空间变换参数的新的能量函数，通过确定性退火算法，可以获得最优的匹配矩阵和空间变换参数，从而解决点的对应性问题和出界点(outliers)确定．实验结果表明，算法具有较强的鲁棒性，具有较高的配准精度和较快的计算速度．     

A new graph matching method for point-set correspondence using the EM algorithm and Softassign

Finding correspondences between two point-sets is a common step in many vision applications (e.g., image matching or shape retrieval). We present a graph matching method to solve the point-set correspondence problem, which is posed as one of mixture modelling. Our mixture model encompasses a model of structural coherence and a model of affine-invariant geometrical errors. Instead of absolute positions, the geometrical positions are represented as relative positions of the points with respect to each other. We derive the Expectation–Maximization algorithm for our mixture model. In this way, the graph matching problem is approximated, in a principled way, as a succession of assignment problems which are solved using Softassign. Unlike other approaches, we use a true continuous underlying correspondence variable. We develop effective mechanisms to detect outliers. This is a useful technique for improving results in the presence of clutter. We evaluate the ability of our method to locate proper matches as well as to recognize object categories in a series of registration and recognition experiments. Our method compares favourably to other graph matching methods as well as to point-set registration methods and outlier rejectors.     

Approximate geometric pattern matching under rigid motions

We present techniques for matching point-sets in two and three dimensions under rigid-body transformations. We prove bounds on the worst-case performance of these algorithms to be within a small constant factor of optimal and conduct experiments to show that the average performance of these matching algorithms is often better than that predicted by the worst-case bounds