A novel algebraic method for kernel-based object tracking

In the present paper, a new tracking method based on kernel tracking is proposed. The proposed method employs a novel algebraic algorithm to get the kernel movement. In contrast to the mean-shift method which uses a weighted kernel to reduce the effect of the background, the algebraic algorithm of the proposed method allows dividing the candidate area into two parts in order to identify the object and background regions. To detect the object and background regions, we propose measuring the similarity of weighted histogram for each part. The experiments show the superiority of the proposed method for the removal of the background. The effect of noise and background clutter is reduced by segmentation of the object which produces the narrow histogram. In conclusion, the ability of the proposed method for tracking in crowded and cluttered scenes is demonstrated.     

Approximate Bayesian multibody tracking

Visual tracking of multiple targets is a challenging problem, especially when efficiency is an issue. Occlusions, if not properly handled, are a major source of failure. Solutions supporting principled occlusion reasoning have been proposed but are yet unpractical for online applications. This paper presents a new solution which effectively manages the trade-off between reliable modeling and computational efficiency. The hybrid joint-separable (HJS) filter is derived from a joint Bayesian formulation of the problem, and shown to be efficient while optimal in terms of compact belief representation. Computational efficiency is achieved by employing a Markov random field approximation to joint dynamics and an incremental algorithm for posterior update with an appearance likelihood that implements a physically-based model of the occlusion process. A particle filter implementation is proposed which achieves accurate tracking during partial occlusions, while in cases of complete occlusion, tracking hypotheses are bound to estimated occlusion volumes. Experiments show that the proposed algorithm is efficient, robust, and able to resolve long-term occlusions between targets with identical appearance.     

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.     

Approximate methods in Bayesian point process spatial models

A range of point process models which are commonly used in spatial epidemiology applications for the increased incidence of disease are compared. The models considered vary from approximate methods to an exact method. The approximate methods include the Poisson process model and methods that are based on discretization of the study window. The exact method includes a marked point process model, i.e., the conditional logistic model. Apart from analyzing a real dataset (Lancashire larynx cancer data), a small simulation study is also carried out to examine the ability of these methods to recover known parameter values. The main results are as follows. In estimating the distance effect of larynx cancer incidences from the incinerator, the conditional logistic model and the binomial model for the discretized window perform relatively well. In explaining the spatial heterogeneity, the Poisson model (or the log Gaussian Cox process model) for the discretized window produces the best estimate.     

A kernel-based trend pattern tracking system for portfolio optimization

We propose a novel kernel-based trend pattern tracking (KTPT) system for portfolio optimization. It includes a three-state price prediction scheme, which extracts both of the following and reverting patterns from the asset price trend to make future price predictions. Moreover, KTPT is equipped with a novel kernel-based tracking system to optimize the portfolio, so as to capture a potential growth of the asset price effectively. The kernel measures the similarity between the current portfolio and the predicted price relative to control the influence of each asset when optimizing the portfolio, which is different from some previous kernels that measure the probability of occurrence of a price relative. Extensive experiments on 5 benchmark datasets from real-world stock markets with various assets in different time periods indicate that KTPT outperforms other state-of-the-art strategies in cumulative wealth and other risk-adjusted metrics, showing its effectiveness in portfolio optimization.     

Neuro-probabilistic model for object tracking

Pattern Analysis and Applications - Occlusion is one of the major challenges for object tracking in real-life scenario. Various techniques in particle filter framework have been developed to solve...     

Bayesian object matching

Matching of object refers to the problem of inferring unknown co-occurrence or alignment between observations or samples in two data sets. Given two sets of equally many samples, the task is to find for each sample a representative sample in the other set, without prior knowledge on a distance measure between the sets. Given a distance measure, the problem would correspond to a linear assignment problem, the problem of finding a permutation that re-orders samples in one set to minimize the total distance. When no such measure is available, we need to consider more complex solutions. Typical approaches maximize statistical dependency between the two sets, whereas in this work we present a Bayesian solution that builds a joint model for the two sources. We learn a Bayesian canonical correlation analysis model that includes a permutation parameter for re-ordering the samples in one of the sets. We provide both variational and sampling-based inference for approximative Bayesian analysis, and demonstrate on three data sets that the resulting methods outperform the earlier solutions.     

Kernel-based object tracking

A new approach toward target representation and localization, the central component in visual tracking of nonrigid objects, is proposed. The feature histogram-based target representations are regularized by spatial masking with an isotropic kernel. The masking induces spatially-smooth similarity functions suitable for gradient-based optimization, hence, the target localization problem can be formulated using the basin of attraction of the local maxima. We employ a metric derived from the Bhattacharyya coefficient as similarity measure, and use the mean shift procedure to perform the optimization. In the presented tracking examples, the new method successfully coped with camera motion, partial occlusions, clutter, and target scale variations. Integration with motion filters and data association techniques is also discussed. We describe only a few of the potential applications: exploitation of background information, Kalman tracking using motion models, and face tracking.     

时空运动显著性的目标跟踪

目的 在目标跟踪过程中,运动信息可以预测目标位置,忽视目标的运动信息或者对其运动方式的建模与实际差异较大,均可能导致跟踪失败。针对此问题,考虑到视觉显著性具有将注意快速指向感兴趣目标的特点,将其引入目标跟踪中,提出一种基于时空运动显著性的目标跟踪算法。方法 首先,依据大脑视皮层对运动信息的层次处理机制,建立一种自底向上的时空运动显著性计算模型,即通过3D时空滤波器完成对运动信号的底层编码、最大化汇集算子完成运动特征的局部编码;利用视频前后帧之间的时间关联性,通过时空运动特征的差分完成运动信息的显著性度量,形成时空运动显著图。其次,在粒子滤波基本框架之下,将时空运动显著图与颜色直方图相结合,来衡量不同预测状态与观测状态之间的相关性,从而确定目标的状态,实现目标跟踪。结果 与其他跟踪方法相比,本文方法能够提高目标跟踪的中心位置误差、精度和成功率等指标;在光照变化、背景杂乱、运动模糊、部分遮挡及形变等干扰因素下,仍能够稳定地跟踪目标。此外,将时空运动显著性融入其他跟踪方法,能够改善跟踪效果,进一步验证了运动显著性对于运动目标跟踪的有效性。结论 时空运动显著性可以有效度量目标的运动信息,增强运动显著的目标区域,抑制干扰区域,从而提升跟踪性能。     

Collaborative strategy for visual object tracking

Multimedia Tools and Applications - Adaptively learning the difference between object and background, discriminative trackers are able to overcome the complex background problem in visual object...     

融合典型纹理特征的粒子滤波目标跟踪方法

针对图像目标跟踪中,跟踪窗口易受噪声扰动所产生的跟踪不稳定问题。创造性地结合多种典型纹理特征和粒子滤波算法,将其应用于实时跟踪领域。选择3种典型的纹理特征,即灰度共生矩阵纹理特征、幅值与方向加权的梯度纹理特征、局部二进制模式纹理特征进行跟踪实验。通过对比实验,在精度与速度两方面测试纹理特征作为跟踪特征的实际效果。作为跟踪中特征的选择,实验结果说明灰度共生矩阵纹理信息在抗扰动与实时处理方面表现出良好的属性特征。     

Efficient edge-based object tracking

Object tracking has been widely applied to video surveillance, robot localization and human-computer interaction. In this paper, an edge-based tracking algorithm is proposed. We extract the feature points by efficiently utilizing the image edges in the object region. Then the parameter vector of the object's motion model is estimated based on minimizing the sum-of-squared differences between the reference feature points in the reference frame and the observed feature points in the tracking sequence frame. The experiments show that the edge-based tracking algorithm proposed by us can track object efficiently under uniform and varying illumination conditions.     

Agent-based reconfigurable architecture for real-time object tracking

Most conventional object tracking algorithms are implemented on general-purpose processors in software due to its great flexibility. However, the real-time performance is hard to achieve due to the inherent characteristics of the sequential processing of these processors. To tackle this issue, a reconfigurable system-on-chip (rSoC) platform with microprocessors and FPGAs is applied in this paper. To simplify the hardware/software interface, a Belief–Desire–Intention (BDI)-based multi-agent architecture is proposed as the unified framework. Then an agent-based task graph and two heuristic partitioning methods are proposed to partition the hardware and software on an rSoC platform. Compared to the module-based architecture, this BDI-based multi-agent architecture provides more efficiency, flexibility, autonomy, and scalability for the real-time tracking systems. A particle swarm optimization (PSO)-based object detection and tracking algorithm is applied to evaluate the proposed architecture. Extensive experimental results of object tracking demonstrate that the proposed architecture is efficient and highly robust with real-time performance.     

改进的粒子滤波器目标跟踪方法

针对现有粒子滤波器目标跟踪算法采用单一颜色直方图特征在目标建模中的缺点和不足,提出了一种将目标颜色特征和不变矩特征融合建立目标模型的改进方法,粒子权重由环境决定的两种特征欧式距离加权生成.实验结果表明,该方法改进了单一颜色特征描述目标在跟踪过程中对抗一些干扰的不足,在不影响实时性的基础上提高了跟踪的准确性和鲁棒性.     

改进的粒子滤波器目标跟踪方法

针对现有的粒子滤波跟踪方法存在的不足,提出了一种改进的粒子滤波器方法用于运动目标跟踪.将颜色直方图和边缘直方图结合起来建立目标的参考模型,有效地克服了使用单一特征建模的缺点,提高了跟踪的准确性.分别计算目标颜色模型和目标边缘模型与粒子的欧几里德距离,使用这2个距离作为粒子权值计算的重要依据.实验结果表明该算法具有较高的实时性、准确性和鲁棒性.     

Online parameter tuning for object tracking algorithms

Object tracking quality usually depends on video scene conditions (e.g. illumination, density of objects, object occlusion level). In order to overcome this limitation, this article presents a new control approach to adapt the object tracking process to the scene condition variations. More precisely, this approach learns how to tune the tracker parameters to cope with the tracking context variations. The tracking context, or context, of a video sequence is defined as a set of six features: density of mobile objects, their occlusion level, their contrast with regard to the surrounding background, their contrast variance, their 2D area and their 2D area variance. In an offline phase, training video sequences are classified by clustering their contextual features. Each context cluster is then associated to satisfactory tracking parameters. In the online control phase, once a context change is detected, the tracking parameters are tuned using the learned values. The approach has been experimented with three different tracking algorithms and on long, complex video datasets. This article brings two significant contributions: (1) a classification method of video sequences to learn offline tracking parameters and (2) a new method to tune online tracking parameters using tracking context.     

用于目标跟踪的智能群体优化滤波算法

针对目标跟踪中的状态估计，提出一种智能群体优化滤波算法。算法在贝叶斯滤波的基础上，运用智能群体优化的3种运动模型估计目标的后验状态，其中内聚运动在保持了粒子多样性的情况下增加了样本的权值，分离运动和排列运动相协调能够更加准确地预测下一时刻目标的先验状态。实验结果表明:与标准粒子滤波相比，该算法能够更加准确地估计非线性系统中的后验状态，在复杂多变的场景环境中，表现出更高的跟踪准确性。