自适应分块多线索融合粒子滤波跟踪方法

多线索融合是解决复杂情况下跟踪问题的有效手段, 为此提出一种基于自适应分块目标模型的多线索融合 粒子滤波跟踪方法. 根据目标颜色分布自适应分块建立目标描述模型, 可提高对目标初始描述的适应性; 采用多线索融合粒子滤波跟踪, 在跟踪过程中能根据子块可靠程度动态调整权重, 提高对剧烈光照变化、目标姿态变化、遮挡等复杂情况的适应性. 实验结果表明, 所提出的跟踪方法在多种复杂情况下能准确有效地跟踪目标.

     

多线索融合和区域划分的粒子滤波跟踪算法

提出一种多线索动态融合和目标区域划分的粒子滤波视觉跟踪算法。在粒子滤波框架基础上,选取颜色、纹理、边缘线索于目标模型中,采用带权重的乘性融合策略自适应计算粒子权重,并实时更新目标模型。为增强在遮挡时的跟踪能力,采用局部目标而非整个运动目标作为粒子目标模型。实验结果表明,改进后的算法比简单的线索融合、传统的粒子滤波模型选取方法更能鲁棒并实时地跟踪目标。     

Visual tracking by fusing multiple cues with context-sensitive reliabilities

Many researchers argue that fusing multiple cues increases the reliability and robustness of visual tracking. However, how the multi-cue integration is realized during tracking is still an open issue. In this work, we present a novel data fusion approach for multi-cue tracking using particle filter. Our method differs from previous approaches in a number of ways. First, we carry out the integration of cues both in making predictions about the target object and in verifying them through observations. Our second and more significant contribution is that both stages of integration directly depend on the dynamically changing reliabilities of visual cues. These two aspects of our method allow the tracker to easily adapt itself to the changes in the context, and accordingly improve the tracking accuracy by resolving the ambiguities.     

Cooperative fusion particle filter tracker

Robust visual tracking has become an important topic in the field of computer vision. Integrating multiple cues has proved to be a promising approach to visual tracking in situations where no single cue is suitable. In this work, a new particle filter based visual tracking algorithm is proposed. By introducing a new cooperative fusion strategy, the proposed tracker has better fault tolerance ability than the traditional methods. Experiments are performed in various tracking scenes to evaluate the proposed algorithm, and the results show improved tracking accuracy.     

以颜色和形状直方图为线索的粒子滤波人脸跟踪

跟踪器的设计和跟踪线索的选择与表达是人脸跟踪中的两大关键因素,针对一般人脸跟踪算法中常用简单椭圆来描述人脸形状线索时易受背景干扰的缺点,以及视频目标跟踪中动态模型和观测模型的非线性非高斯特点,提出了一种以颜色和形状直方图为线索的粒子滤波人脸跟踪算法,该算法在粒子滤波基本框架之下,引入了一种新的用直方图来描述人脸形状的方法,并对其进行了改进,用来作为人脸跟踪的形状线索。同时,为了减轻背景干扰,提出了一种经验有效边缘的检测方法。实验表明,该跟踪方法不仅能有效地处理人脸旋转、背景中的肤色干扰和部分遮掩问题,并且能够在由于大面积遮掩等原因而丢失目标的情况下,及时有效地重新捕获已丢失的目标。     

A new parallel particle filter face tracking method based on heterogeneous system

This paper proposed a multi-cue-based face-tracking algorithm with the supporting framework using parallel multi-core and one Graphic Processing Unit (GPU). Due to illumination and partial-occlusion problems, face tracking usually cannot stably work based on a single cue. Focusing on the above-mentioned problems, we first combined three different visual cues??color histogram, edge orientation histogram, and wavelet feature??under the framework of particle filters to considerably improve tracking performance. Furthermore, an online updating strategy made the algorithm adaptive to illumination changes and slight face rotations. Subsequently, attempting two parallel approaches resulted in real-time responses. However, the computational efficiency decreased considerably with the increase of particles and visual cues. In order to handle the large amount of computation costs resulting from the introduced multi-cue strategy, we explored two parallel computing techniques to speed up the tracking process, especially the most computation-intensive observational steps. One is a multi-core-based parallel algorithm with a MapReduce thread model, and the other is a GPU-based speedup approach. The GPU-based technique uses features-matching and particle weight computations, which have been put into the GPU kernel. The results demonstrate that the proposed face-tracking algorithm can work robustly with cluttered backgrounds and differing illuminations; the multi-core parallel scheme can increase the speed by 2?C6 times compared with that of the corresponding sequential algorithms. Furthermore, a GPU parallel scheme and co-processing scheme can achieve a greater increase in speed (8×?C12×) compared with the corresponding sequential algorithms.     

基于核函数粒子滤波和多特征自适应融合的目标跟踪

经典粒子滤波及其改进算法在观测模型与真实情况存在偏差时会导致滤波发散,针对这一问题,提出一种核函数粒子滤波算法.该算法根据目标状态与粒子状态之间的距离,利用核函数产生权值对粒子进行二次加权,根据粒子的二次加权结果进行粒子重采样;以改进的粒子滤波算法为框架,提出了一种自适应多特征融合目标跟踪方法,利用相似性度量动态地评价特征对目标与背景的区分能力,并自适应地计算特征融合权重,以适应目标跟踪过程中目标与背景的变化,提高目标跟踪的鲁棒性.实验结果表明,文中提出的目标跟踪方法比经典粒子滤波目标跟踪方法具有更强的抗干扰性能和较高的跟踪精度.     

基于多观测模型的粒子滤波头部跟踪算法

粒子滤波在非线性和非高斯问题上具有独特的优越性,但在视频跟踪过程中,其跟踪性能却在很大程度上依赖于观测模型的选择。为了解决被跟踪目标特征状态随时间变化而与粒子观测模型不匹配的问题,提出了一种新的粒子滤波算法,即将被跟踪目标的不同特征状态与粒子观测模型相结合,形成一组具有不同观测模型的粒子,并且在跟踪过程中,对应不同观测模型的粒子根据被跟踪目标所表现的特征线索的变化而相互转换,从而动态刻画了被跟踪目标特征变化的过程。实验结果表明,本算法能够有效处理由于头部旋转而导致跟踪性能下降甚至丢失跟踪目标的问题,提高了跟踪的准确性,并且具有较好的鲁棒性。     

红外可见光目标的空间直方图表示与联合跟踪

目的 针对融合跟踪中的实时性和准确性问题,提出一种基于二阶空间直方图联合的红外与可见光目标融合跟踪算法。方法 该算法以二阶空间直方图为目标表示模型,通过将红外的目标相似度和可见光的目标相似度进行加权融合,来构建新的目标函数;并依据核跟踪推理机制导出目标的联动位移公式;最后使用均值漂移程序实现目标的自动搜索。此外,算法还实现了融合权值的自适应调节和目标模型的在线更新。结果 实验中选取了4组典型的红外可见光视频对进行跟踪,测试了算法在夜间环境、背景阴影、目标交汇与拥簇,以及目标遮挡等场合下的跟踪性能,并与L₁跟踪器（L1T）、基于区域模糊动态融合的跟踪器（FRD）,以及基于联合直方图的跟踪器在平均中心误差、平均重叠率、成功率以及平均跟踪时间等指标上进行了定量比较,得到各算法在这4组视频上的对应性能指标数据分别为本文算法（6.664,0.702,0.921,0.009）、L1T跟踪红外目标（25.53,0.583,0.742,0.363）、L1T跟踪可见光目标（31.21,0.359,0.459,0.293）、FRD（10.73,0.567,0.702,0.565）、JHT（15.07,0.622,0.821,0.001）,发现本文算法的平均准确率比其他跟踪算法分别高约23%、14%和8%,而平均成功率分别高约32%、46%和10%。结论 本文算法在处理场景拥簇、光照变化以及空间信息保持等方面要优于传统的单源跟踪方法,适用于夜间环境、背景阴影以及背景拥簇等场景下目标跟踪,对帧频为30 帧/s的视频数据,算法可同时在线跟踪到4个目标。     

Dynamic appearance model for particle filter based visual tracking

This paper made major research on the target representation problem, which plays a significant role in visual tracking, but has received little attention in most researches. In order to fulfill the requirements of tracking robustness and effectiveness in practical conditions, a dynamic appearance model is constructed. Due to particle filter's excellent characteristics, it is employed in this paper not only to estimate target's state, but also to construct the dynamic observation model integrated by multiple cues. In the proposed method, a dynamic multi-cue integration model is constructed for particle filter framework. And a systematic study is done on evaluating cue's weight. Specially, a particle filter based weight tracker is designed to update multi-cue's integrating manner online, so as to adapt the observation model to target's appearance changes. In such a way, a double-particle-filter based tracking framework is formed, and it is field tested on a variety of videos in different tracking conditions. In the experiments and comparisons, the applicable conditions of the proposed dynamic model are discussed, and its robustness and effectiveness are demonstrated.     

A novel approach of multi-stage tracking for precise localization of target in video sequences

Visual tracking methods are mostly based on single stage state estimation that limitedly caters to precise localization of target under dynamic environment such as occlusion, object deformation, rotation, scaling and cluttered background. In order to address these issues, we introduce a novel multi-stage coarse-to-fine tracking framework with quick adaptation to environment dynamics. The key idea of our work is to propose two-stage estimation of object state and to develop an adaptive fusion model. Coarse estimation of object state is achieved using optical flow and multiple fragments are generated around this approximation. Precise localization of object is obtained through evaluation of these fragments using three complementary cues. Adaptation of proposed tracker to dynamic environment changes is quick due to incorporation of context sensitive cue reliability, which encompass its direct application for development of expert system for video surveillance. In addition, proposed framework caters to object rotation and scaling through a random walk state model and rotation invariant features. The proposed tracker is evaluated over eight- benchmarked color video sequences and competitive results are obtained. As an average of the outcomes, we achieved mean center location error (in pixels) of 6.791 and F-measure of 0.78. Results demonstrate that proposed tracker not only outperforms various state-of-the-art trackers but also effectively caters to various dynamic environments.     

基于Mean Shift和自适应预测的非刚性目标跟踪算法

传统Ｍｅａｎ Ｓｈｉｆｔ跟踪算法在目标发生机动或存在遮挡的情况下跟踪效果不理想．对此,结合目标的形状特征和颜色的可区分度对传统的颜色直方图进行改进,给出了将Ｍｅａｎ Ｓｈｉｆｔ和卡尔曼滤波器或粒子滤波器相结合的目标运动自适应跟踪算法,并针对粒子滤波器计算量大的问题,给出了运用两种不同运动式粒子进行有效预测的方法．结果表明,该算法可实现快速的非刚性目标跟踪,对目标的不规则运动和严重遮挡具有很好的鲁棒性．     

Hybrid generative–discriminative hash tracking with spatio-temporal contextual cues

Visual object tracking is of a great application value in video monitoring systems. Recent work on video tracking has taken into account spatial relationship between the targeted object and its background. In this paper, the spatial relationship is combined with the temporal relationship between features on different video frames so that a real-time tracker is designed based on a hash algorithm with spatio-temporal cues. Different from most of the existing work on video tracking, which is regarded as a mechanism for image matching or image classification alone, we propose a hierarchical framework and conduct both matching and classification tasks to generate a coarse-to-fine tracking system. We develop a generative model under a modified particle filter with hash fingerprints for the coarse matching by the maximum a posteriori and a discriminative model for the fine classification by maximizing a confidence map based on a context model. The confidence map reveals the spatio-temporal dynamics of the target. Because hash fingerprint is merely a binary vector and the modified particle filter uses only a small number of particles, our tracker has a low computation cost. By conducting experiments on eight challenging video sequences from a public benchmark, we demonstrate that our tracker outperforms eight state-of-the-art trackers in terms of both accuracy and speed.

     

Fragments based tracking with adaptive cue integration

In this paper, we address the issue of part-based tracking by proposing a new fragments-based tracker. The proposed tracker enhances the recently suggested FragTrack algorithm to employ an adaptive cue integration scheme. This is done by embedding the original tracker into a particle filter framework, associating a reliability value to each fragment that describes a different part of the target object and dynamically adjusting these reliabilities at each frame with respect to the current context. Particularly, the vote of each fragment contributes to the joint tracking result according to its reliability, and this allows us to achieve a better accuracy in handling partial occlusions and pose changes while preserving and even improving the efficiency of the original tracker. In order to demonstrate the performance and the effectiveness of the proposed algorithm we present qualitative and quantitative results on a number of challenging video sequences.     

多特征融合的自适应性粒子滤波跟踪算法

为提高粒子滤波视觉目标跟踪算法的实时性与鲁棒性,提出了一种基于多特征融合的自适应性粒子滤波跟踪算法。该算法利用颜色和结构特征表示目标,将两者融合于粒子滤波的框架中,利用融合后的信息计算粒子的权值,以降低算法受目标形变及复杂环境的影响。同时,根据跟踪预测的准确程度动态计算跟踪所需的粒子数目,对采样粒子集进行自适应调整,以提高粒子质量,降低粒子数量,减少算法运算时间。实验结果表明,所提算法对于每帧图像的平均计算时间相对于传统混合跟踪算法缩短了将近一半,而且算法的鲁棒性较强。     

一种鲁棒的多特征融合目标跟踪新算法

仅利用单一的目标特征进行跟踪是大多数跟踪算法鲁棒性不高的重要原因。提出了一种新的多特征融合目标跟踪算法,该算法将目标的颜色、纹理、边缘、运动特征统一使用直方图模型进行描述,以降低算法受目标形变和部分遮挡的影响,在Auxiliary粒子滤波框架内将所有特征观测进行概率融合,以突出状态后验分布中目标真实状态对应的峰值,从而有效避免了复杂背景的干扰,并给出了一种有效的融合系数计算方法,使融合结果更加准确可靠。实验结果表明,该算法能同时处理刚性与非刚性目标的跟踪,较单一特征的跟踪算法具有明显的优势,对复杂背景下的跟踪具有较高的鲁棒性。与现有多特征融合算法的比较也证明了本文算法的有效性。     

灰度与速度线索融合红外小目标跟踪

红外小目标跟踪易受到相似目标与背景的干扰,针对此问题提出一种融合灰度与速度线索的红外小目标跟踪算法。该算法通过快速时域高通滤波器滤除噪声并突出目标,利用主分量分析提取速度特征;以分层粒子滤波为框架,首先利用高通滤波图像灰度核函数加权直方图进行第1层粒子滤波,粗略地估计目标状态;然后利用速度线索进行第2层粒子滤波,精确地估计目标状态。实验结果表明,提出的红外小目标跟踪算法具有较强的抗干扰性能和较高的跟踪精度。     

基于粒子滤波后验概率分布的多特征融合跟踪

在光照和目标形变等外部条件变化的情况下,仅利用目标的单一特征难以鲁棒的跟踪目标。提出了一种基于粒子滤波后验概率分布的多特征融合跟踪算法,在粒子滤波跟踪框架下,用直方图模型表征目标的颜色和边缘特征,通过两种特征后验概率之间的"协作"与"学习"实现特征融合,各种场景的试验结果比较表明,新的融合跟踪算法比仅用单一特征跟踪、现有的多特征融合算法具有更好的稳定性和鲁棒性,特别是针对环境光照和目标背景变化较大的情况更具有优势。     

基于双准则自适应融合的目标跟踪算法

针对单一评判准则较难适应复杂环境下的目标跟踪问题,提出了一种基于双评判准则自适应融合的跟踪算法。在该算法中,空间直方图被用作目标表示模型,候选目标与目标模板之间的相似度、以及候选目标与其邻近背景区域之间的对比度被作为目标评判双准则,而目标函数(或似然函数)则由两个准则的加权融合而成。算法是在粒子滤波框架下实现的目标搜索,并采用了模糊逻辑对相似度和对比度的权值进行自适应调节。对人、动物等多个挑战性运动目标的跟踪结果表明,与增量学习跟踪、ι₁跟踪等最新跟踪器相比,所提算法在处理目标的遮挡、形变、旋转以及表观变化方面的综合性能更好,其成功率和平均重叠率指标分别在80%和0.76以上。     

基于DST-PCR5多目标自适应视觉跟踪方法

复杂场景下实现快速稳定地自适应跟踪是视觉领域亟需解决的课题之一, 利用目标的多特征信息进行高效融合是提升跟踪算法鲁棒性能的重要途径。本文首先基于DST(Dempster-Shafer Theory)和PCR5(Proportional Conflict Redistribution No.5)设计一种新的合并策略融合运动目标的颜色和纹理特征,其次在粒子滤波框架下建立复杂场景下的多目标自适应跟踪模型,最终实现了复杂场景下多特征信息融合的自适应视觉跟踪。实验结果及性能分析表明,该方法在不良的跟踪条件下,高冲突证据的自适应处理能力得到明显改善,有效提高了粒子的使用效率和跟踪的鲁棒性,可以较好实现复杂场景下准确、稳定地多目标跟踪。