基于粒子滤波的多特征融合视频行人跟踪算法

针对车载视频行人跟踪问题,提出一种基于粒子滤波框架下的多特征融合跟踪算法。为克服车载视频中行人运动与摄像机运动产生的非线性和非高斯性,采用基于蒙特卡罗抽样的粒子滤波跟踪算法,使用一阶自回归动态模型预测目标状态,观测模型自适应加权融合的4种互补性特征。实验结果表明,与没有粒子滤波和多特征融合的跟踪算法相比,在相同精确率水平上,该算法的召回率提高20%以上。     

基于粒子滤波的双模图像融合自适应跟踪

针对视频跟踪中仅利用目标的单特征容易导致跟踪失败的问题,提出一种基于粒子滤波的可见光与红外序列图像相融合的自适应目标跟踪算法;该算法在粒子滤波跟踪算法框架下,根据单一信源运动目标序列图像的品质因子,利用自适应加权融合策略重构双模序列图像的特征选择机制,建立了基于自适应融合算法的系统观测概率模型和状态空间层次采样多特征融合跟踪算法,实现了对双模序列图像的融合以及对运动目标的稳健跟踪;跟踪试验结果表明,该算法可以有效实现对运动目标的稳健、准确跟踪。     

基于约束知识的IP-MCMC-PF目标跟踪方法研究

针对粒子滤波算法在有干扰的目标跟踪中可能出现的粒子多样性减少和精度下降等问题,研究并实现了一种新的基于约束知识的IP-MCMC-PF目标跟踪方法。该方法首先通过约束知识提高粒子预测的准确性,并通过多链并行的IP-MCMC方法提高粒子的多样性,有效地解决粒子退化问题;在此基础上通过PN学习算法在线更新抽样粒子的抽样分布和检测器的训练样本,实现目标跟踪算法的在线学习,有效提高了复杂背景下目标跟踪的准确度和自适应性。实验结果表明,该方法在遮挡、形变、光照变化等多种干扰的情形下都具有很好的跟踪效果。     

基于当前统计模型的改进粒子滤波算法

基于“当前”统计模型,提出了双站无源被动跟踪的改进粒子滤波算法．该算法使用扩展卡尔曼滤波提议分布的粒子滤波,融合双站测量数据,包含了残差重抽样步骤以及马尔可夫链蒙特卡罗法等技巧．在双站测量的被动跟踪试验中,比较了各种滤波方式．仿真结果证实,该改进算法能有效跟踪高度机动的目标．     

基于序列蒙特卡罗滤波的车辆跟踪算法研究

针对非线性目标跟踪中模型或函数近似等最优估计缺陷问题,提出了基于帧间预测和特征匹配的序列蒙特卡罗滤波跟踪算法.算法中采用在HSV色彩下的空间加权直方图描述跟踪车辆的状态特征,通过简单的随机漂移模型实现估测样本的帧间传递,利用估测样本与期望目标间的相似度量完成样本权重赋值运算,最终利用加权样本值估计实现待测目标的后验状态.实验结果表明,基于序列蒙特卡罗滤波的车辆跟踪算法计算简单有效,能够在复杂环境下实时、准确跟踪道路上无规律、非线性运动的车辆,并能够有效适应车辆部分遮挡和短时丢失等情况.     

运动背景下基于粒子滤波的目标跟踪

粒子滤波方法是一种针对非刚性目标运动跟踪的有效工具。运用基于贝叶斯估计的粒子滤波算法,对复杂的运动背景下目标移动进行跟踪。论述了贝叶斯估计理论,推导粒子滤波过程,并将状态粒子决定的区域所对应的色彩直方图用作测量,与目标参考直方图相比较,得出最佳的后验估计。运用窗口粒子平均方法确定目标的坐标,实现跟踪。算法采用单目标以及多目标序列图象进行跟踪实验,并与均值移动(mean-shift)跟踪算法结果进行比较,证明该跟踪算法更为有效。     

流形背景感知的相关滤波目标跟踪

针对相关滤波跟踪算法在相似背景、遮挡、快速运动、运动模糊等复杂场景下目标易丢失的问题,提出一种新的基于流形背景感知的相关滤波目标跟踪方法。首先,选取目标区域,提取目标的外观特征,建立目标模型;然后,以目标所在位置为原点,采用双指数分布构建流形搜索区域,并根据目标的运动速度和运动方向动态调整流形搜索区域的搜索范围和搜索角度,提取流形搜索区域内的背景信息,将背景信息与目标特征模型进行滤波器训练,得到滤波器模板;最后,以滤波器模板来确定目标位置,进行目标跟踪。提出的流形背景感知算法,根据目标运动的速度和方向,采用动态搜索机制进行搜索,涵盖了目标随机运动的大概率空间范围,在复杂场景下能够有效搜索目标,并控制了计算量,提升了目标跟踪算法的精度和速度。该方法在标准数据集OTB100上进行了大量的实验,实验结果表明,相较于其他主流算法,该算法对相似背景、遮挡、快速运动、运动模糊等复杂条件下的目标跟踪具有很好的准确率、实时性和鲁棒性。     

多特征融合的退火粒子滤波目标跟踪

针对传统粒子滤波的建议分布没有利用到当前观测信息的缺点,提出了一种基于多特征融合的退火算法来改进建议分布的粒子滤波跟踪方法。该方法解决了高维状态下计算量大和粒子数匮乏问题。采用退火方法在蒙特卡洛重要采样范围内产生更好的建议分布,并用退火似然性抽样来代替简单的先验概率抽样。在似然逼近中,应用颜色和边缘相融合的图像特征属性在不同的退火层加权来产生权重功能函数。用该方法对复杂背景下和存在遮挡情况下的运动目标进行跟踪,结果表明该方法有较高的跟踪精度和较强的稳定性。     

一种改进的基于Camshift的粒子滤波实时目标跟踪算法

为了能够快速和准确地跟踪运动目标,提出了一种改进的基于Camshift的粒子滤波算法。在粒子滤波框架下,首先对传统目标模型进行改进,提出一种新的融合目标颜色信息和运动信息的模型,以增强目标跟踪的稳健性和准确性;同时为了提高跟踪的效率,将一种改进的Camshift算法嵌入到粒子滤波中,用来重新分配随机粒子样本,使之向目标状态的最大后验概率密度方向移动。实验结果表明,与传统的粒子滤波算法或Camshift算法相比,该方法能有效处理目标快速运动或背景存在强干扰等情况,实现对目标快速和稳健的跟踪。     

一种基于多样性优化的视频目标跟踪方法

针对粒子滤波算法在视频目标跟踪过程中出现的粒子退化问题,提出一种新的基于多样性优化的粒子滤波跟踪算法。融入基于莱维飞行机制的布谷鸟搜索优化算法,扩大了搜索范围,充分保留了有效粒子的数量和粒子的多样性。在MATLAB 7.0运行环境下进行仿真实验,将该算法与原始粒子滤波算法及基于粒子群优化的粒子滤波改进算法进行状态估计实验对比以及运动目标跟踪实验对比。实验结果表明:该算法具有良好的运行效果,改善了粒子退化与匮乏现象,对视频运动目标可获得较理想的跟踪精度及良好实时性和鲁棒性。     

Overview of Bayesian sequential Monte Carlo methods for group and extended object tracking

This work presents the current state-of-the-art in techniques for tracking a number of objects moving in a coordinated and interacting fashion. Groups are structured objects characterized with particular motion patterns. The group can be comprised of a small number of interacting objects (e.g. pedestrians, sport players, convoy of cars) or of hundreds or thousands of components such as crowds of people. The group object tracking is closely linked with extended object tracking but at the same time has particular features which differentiate it from extended objects. Extended objects, such as in maritime surveillance, are characterized by their kinematic states and their size or volume. Both group and extended objects give rise to a varying number of measurements and require trajectory maintenance. An emphasis is given here to sequential Monte Carlo (SMC) methods and their variants. Methods for small groups and for large groups are presented, including Markov Chain Monte Carlo (MCMC) methods, the random matrices approach and Random Finite Set Statistics methods. Efficient real-time implementations are discussed which are able to deal with the high dimensionality and provide high accuracy. Future trends and avenues are traced.     

Depth map calculation for a variable number of moving objects using markov sequential object processes

We advocate the use of Markov sequential object processes for tracking a variable number of moving objects through video frames with a view towards depth calculation. A regression model based on a sequential object process quantifies goodness of fit; regularization terms are incorporated to control within and between frame object interactions. We construct a Markov chain Monte Carlo method for finding the optimal tracks and associated depths and illustrate the approach on a synthetic data set as well as a sport sequence.     

基于粒子滤波的小波特征跟踪方法研究

该文提出了基于粒子滤波的小波特征跟踪方法。粒子滤波基于蒙特卡罗模拟方法来实现递推贝叶斯滤波,是一种实用的后验概率求解方法。文中研究了目标的Gabor小波网络表示,用一定数量的小波构成一个集合来表示目标特征,各小波的参数由优化方法来确定。构建了基于粒子滤波的跟踪框架,每个粒子表示一种Gabor小波网络的可能形式,并计算与当前图像的相似度。粒子权值与相似度成正比,目标状态的后验概率由粒子加权表示。与传统的“峰值”跟踪方法不同,粒子滤波具有“多峰”的跟踪形式。并结合对光照、噪声不敏感的小波表示形式,具有较强的抗局部遮挡能力。     

Robust object tracking via online dynamic spatial bias appearance models

This paper presents a robust object tracking method via a spatial bias appearance model learned dynamically in video. Motivated by the attention shifting among local regions of a human vision system during object tracking, we propose to partition an object into regions with different confidences and track the object using a dynamic spatial bias appearance model (DSBAM) estimated from region confidences. The confidence of a region is estimated to re ect the discriminative power of the region in a feature space, and the probability of occlusion. We propose a novel hierarchical Monte Carlo (HAMC) algorithm to learn region confidences dynamically in every frame. The algorithm consists of two levels of Monte Carlo processes implemented using two particle filtering procedures at each level and can efficiently extract high confidence regions through video frames by exploiting the temporal consistency of region confidences. A dynamic spatial bias map is then generated from the high confidence regions, and is employed to adapt the appearance model of the object and to guide a tracking algorithm in searching for correspondences in adjacent frames of video images. We demonstrate feasibility of the proposed method in video surveillance applications. The proposed method can be combined with many other existing tracking systems to enhance the robustness of these systems.     

目标跟踪中的改进Monte Carlo滤波算法

传统的Monte Carlo滤波算法在目标跟踪过程中存在严重的采样贫瘠问题,这直接导致了样本集的退化。为了解决这个问题,提出一种改进的Monte Carlo滤波算法。在样本集建立阶段,采用基于视觉机制的方法建立样本集合,使得样本集在与中心距离较近的地方密集,在离中心较远的地方稀疏,这样的样本集合建立方法能够更准确地反映人眼对事物的感知;在样本集传播阶段,获得一个区分样本优劣的阈值,将样本集合分为优劣两种,用重采样的方法对优样本集合采样,采样半数样本,用随机抽样的方法补充其余半数样本,实验结果表明,这种方法可以很好地解决样本退化的问题。     

Nonlinear tracking in a diffusion process with a Bayesian filter and the finite element method

A new approach to nonlinear state estimation and object tracking from indirect observations of a continuous time process is examined. Stochastic differential equations (SDEs) are employed to model the dynamics of the unobservable state. Tracking problems in the plane subject to boundaries on the state-space do not in general provide analytical solutions. A widely used numerical approach is the sequential Monte Carlo (SMC) method which relies on stochastic simulations to approximate state densities. For off-line analysis, however, accurate smoothed state density and parameter estimation can become complicated using SMC because Monte Carlo randomness is introduced. The finite element (FE) method solves the Kolmogorov equations of the SDE numerically on a triangular unstructured mesh for which boundary conditions to the state-space are simple to incorporate. The FE approach to nonlinear state estimation is suited for off-line data analysis because the computed smoothed state densities, maximum a posteriori parameter estimates and state sequence are deterministic conditional on the finite element mesh and the observations. The proposed method is conceptually similar to existing point-mass filtering methods, but is computationally more advanced and generally applicable. The performance of the FE estimators in relation to SMC and to the resolution of the spatial discretization is examined empirically through simulation. A real-data case study involving fish tracking is also analysed.     

基于蒙特卡洛方法的粒子滤波算法研究

针对非线性、非高斯问题,文章详细分析了贝叶斯滤波的原理及其进展.采用近似线性及高斯假设处理,传统的卡尔曼滤波提供了一种很好的解决方案.但是,真实世界的非线性、非高斯问题存在,使得人们得不寻找一种更好的最优滤波方法.基于随机滤波理论、贝叶斯统计量和蒙特卡洛方法的粒子滤波理论迅速发展,并广泛应用到数字通信、目标跟踪、计算机视觉和机器故障诊断领域.     

Bayesian Object Localisation in Images

A Bayesian approach to intensity-based object localisation is presented that employs a learned probabilistic model of image filter-bank output, applied via Monte Carlo methods, to escape the inefficiency of exhaustive search.An adequate probabilistic account of image data requires intensities both in the foreground (i.e. over the object), and in the background, to be modelled. Some previous approaches to object localisation by Monte Carlo methods have used models which, we claim, do not fully address the issue of the statistical independence of image intensities. It is addressed here by applying to each image a bank of filters whose outputs are approximately statistically independent. Distributions of the responses of individual filters, over foreground and background, are learned from training data. These distributions are then used to define a joint distribution for the output of the filter bank, conditioned on object configuration, and this serves as an observation likelihood for use in probabilistic inference about localisation.The effectiveness of probabilistic object localisation in image clutter, using Bayesian Localisation, is illustrated. Because it is a Monte Carlo method, it produces not simply a single estimate of object configuration, but an entire sample from the posterior distribution for the configuration. This makes sequential inference of configuration possible. Two examples are illustrated here: coarse to fine scale inference, and propagation of configuration estimates over time, in image sequences.     

基于Hamiltonian马氏链蒙特卡罗方法的突变运动跟踪

在计算机视觉领域,由镜头切换、目标动力学突变、低帧率视频等引起的突变运动存在极大的不确定性,使得突变运动跟踪成为该领域的挑战性课题.以贝叶斯滤波框架为基础,提出一种基于有序超松弛Hamiltonian马氏链蒙特卡罗方法的突变运动跟踪算法.该算法将Hamiltonian动力学融入MCMC（Markov chain Monte Carlo）算法,目标状态被扩张为原始目标状态变量与一个动量项的组合.在提议阶段,为抑制由Gibbs采样带来的随机游动行为,提出采用有序超松弛迭代方法来抽取目标动量项.同时,提出自适应步长的Hamiltonian动力学实现方法,在跟踪过程中自适应地调整步长,以减少模拟误差.提出的跟踪算法可以避免传统的基于随机游动的MCMC跟踪算法所存在的局部最优问题,提高了跟踪的准确性而不需要额外的计算时间.实验结果表明,该算法在处理多种类型的突变运动时表现出出色的处理能力.     

Combining particle MCMC with Rao-Blackwellized Monte Carlo data association for parameter estimation in multiple target tracking

We consider state and parameter estimation in multiple target tracking problems with data association uncertainties and unknown number of targets. We show how the problem can be recast into a conditionally linear Gaussian state-space model with unknown parameters and present an algorithm for computationally efficient inference on the resulting model. The proposed algorithm is based on combining the Rao-Blackwellized Monte Carlo data association algorithm with particle Markov chain Monte Carlo algorithms to jointly estimate both parameters and data associations. Both particle marginal Metropolis–Hastings and particle Gibbs variants of particle MCMC are considered. We demonstrate the performance of the method both using simulated data and in a real-data case study of using multiple target tracking to estimate the brown bear population in Finland.