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1.
A method was presented to implement the detecting and tracking of moving targets through omnidirectional vision.The method combined optical flow with particle filter arithmetic.in which optical flow field was used to detect and locate moving targets and particle filter was used to track the detected moving objects.According to the circular image character of omnidirectionaI vision.the calculation equation of optical flow field and the tracking arithmetic of particle filter were improved based on the polar coordinates at the omnidirectional center.The edge of a randomly moving object could be detected by optical flow field and was surrounded by a reference region in the particle filter.A dynamic motion model was established to predict particle state.Histograms were used as the features in the reference region and candidate regions.The mutual information(MI)and Gaussian function were combined to calculate particle weights.Finally,the state of tracked object was computed by the total particle states with weights.Experiment results show that the proposed method could detect and track moving objects with better realtime performance and accuracy.  相似文献   

2.
Omnidirectional imaging sensors have been used in more and more applications when a very large field of view is required. In this paper, we investigate the unwrapping, epipolar geometry and stereo rectification issues for omnidirectional vision when the particular mirror model and the camera parameters are unknown in priori. First, the omnidirectional camera is calibrated under the Taylor model, and the parameters related to this model are obtained. In order to make the classical computer vision algorithms of conventional perspective cameras applicable, the ring omnidirectional image is unwrapped into two kinds of panoramas： cylinder and cuboid. Then the epipolar geometry of arbitrary camera configuration is analyzed and the essential matrix is deduced with its properties being indicated for ring images. After that, a simple stereo rectification method based on the essential matrix and the conformal mapping is proposed. Simulations and real data experimental results illustrate that our methods are effective for the omnidirectional camera under the constraint of a single view point.  相似文献   

3.
In airborne tracking,the blind Doppler makes the target undetectable,resulting in tracking difficulties. In this paper,we studied most possible blind-Doppler cases and summed them up into two types:targets' intentional tangential flying to radar and unintentional flying with large tangential speed. We proposed an interacting multiple model(IMM) particle filter which combines a constant velocity model and an acceleration model to handle maneuvering motions. We compared the IMM particle filter with a previous particle filter solution. Simulation results showed that the IMM particle filter outperforms the method in previous works in terms of tracking accuracy and continuity.  相似文献   

4.
Infants' oculomotor tracking develops rapidly but is poorer when there are horizontal and vertical movement components. Additionally, persistence of objects moving through occlusion emerges at 4 months but initially is absent for objects moving obliquely. In two experiments, we recorded eye movements of thirty-two 4-month-old and thirty-two 6-month-old infants (mainly Caucasian-White) tracking horizontal, vertical, and oblique trajectories. Infants tracked oblique trajectories less accurately, but 6-month olds tracked more accurately such that they tracked oblique trajectories as accurately as 4-month olds tracked horizontal and vertical trajectories. Similar results emerged when the object was temporarily occluded. Thus, 4-month olds’ tracking of oblique trajectories may be insufficient to support object persistence, whereas 6-month olds may track sufficiently accurately to perceive object persistence for all trajectory orientations.  相似文献   

5.
针对复杂环境下的多目标跟踪问题提出了一种新的跟踪方法．在检测部分,采用第三级离散小波变换和背景差分进行了目标分割．在跟踪部分,首先利用卡尔曼滤波器和缩放因子估计目标在下一帧中的中心位置和矩形框尺寸,然后在中心关联和区域关联的基础上提出了投射率和遮挡率的概念,并结合投射率和遮挡率推断目标行为．最后针对具体目标行为,自适应地调整跟踪方案和卡尔曼参数实现了多目标跟踪．在遮挡情况下利用部分观测调整估计框以获得目标测量值和最优框尺寸．提出的方法对处于遮挡、新出现以及稳定等情况下的运动目标均具有鲁棒的跟踪性能．实验结果表明提出的方法是有效的．  相似文献   

6.
Variable refractive index in environment matte   总被引：1，自引：0，他引：1  
INTRODUCTION Digital matting and compositing is a popular technique in the film industry, with which we can separate a foreground object, including both its color and opacity, from a background image. The descrip- tion of the separated foreground object is named digital matte. Smith and Blinn (1996) proposed the blue screen matting technique. They formally de- scribed the mathematical solution to the digital mat- ting problem, when either some constraints on the foreground color or a pair…  相似文献   

7.
介绍了一种简单、快速的实时交通图像序列中多目标的跟踪算法,在使用自适应背景差分法分割出运动目标候选区域的基础上,通过形态学操作和降低分辨率的方法,得到连通的目标区域,再使用轨迹关联法实现对多目标的跟踪．实验结果表明该算法较好地解决了跟踪的连续性、实时性、精确度的矛盾,同时满足智能交通监控系统的要求．  相似文献   

8.
运动目标的参数估计是近代计算机视觉领域重要的研究课题．以运动车辆的序列图像为例来分析．考虑到跟踪运动车辆对实时性要求较高的特性,没有采用经典的最小二乘滤波和维纳滤波等,而采用了卡尔曼滤波方法,由于卡尔曼滤波在时域内进行,因此不需要保存更多的数据,使得跟踪结果实时输出。  相似文献   

9.
In this paper, we discuss a class of piecewise linear hyperbolic maps on the 2-torus. These maps arise in the second-order digital fdter with two＇ s complement arithmetic. By introducing codings underlying the map operations, we give some admissibility conditions for symbolic sequences and find some periodic properties of these symbolic sequences. Then we use these conditions to check the admissibility of periodic symbol sequences.  相似文献   

10.
A system dynamics approach to urban water demand forecasting was developed based on the analysis of urban water resources system, which was characterized by multi-feedback and nonlinear interactions among system elements. As an example, Tianjin water resources system dynamic model was set up to forecast water resources demand of the planning years. The practical verification showed that the relative error was lower than 10%. Furthermore, through the comparison and analysis of the simulation results under different development modes presented in this paper, the forecasting results of the water resources demand of Tianjin was achieved based on sustainable utilization strategy of water resources. Supported by National Natural Science Foundation of China (No.50578108), Doctoral Programs Foundation of Ministry of Education of China (No.20050056016), National Key Program for Basic Research (“973” Program, No.2007CB407306-1), Science and Technology Development Foundation of Tianjin (No.033113811 and No.05YFSYSF032), Educational Commission of Hebei Province (No.2008324) and Tianjin Social Key Foundation (No.tjyy08-01-078). ZHANG Hongwei, born in 1956, male, Dr. Prof.  相似文献   

11.
在复杂地物类型背景条件下,多目标跟踪算法通常表现出目标识别与跟踪能力较差问题,特别在被其它地物遮挡后目标跟踪丢失更严重。提出一种改进的基于多源特征提取与特征融合的多目标跟踪算法。为提高目标在复杂背景下的空间分辨力,充分利用对异类物体判别能力较强的高层特征和针对同类不同物体判别能力较强的浅层特征,提高复杂背景下地物目标的识别能力。同时,为了解决物体被遮挡后导致跟踪算法丢失目标问题,利用滤波器获得追踪目标的空间尺度大小,提高跟踪算法的准确性与可靠性。实验表明,多目标跟踪算法识别目标的准确性可达87.5%,误差在[±2.31%]左右,具有良好的尺度估计效果。  相似文献   

12.
在面部特征点的跟踪领域光流算法使用较为广泛。文章使用了Lucas Kanade 光流算法对面部特征点进行跟踪,实验表明,该算法在面部特征点跟踪中可得到较好的跟踪效果。  相似文献   

13.
INTRODUCTIONObjecttrackingisachallengingandimpor tanttaskincomputervision .Someofthemorepopularapplicationsincludevideosurveillanceinstrument,roboticcontrol,andautonomousve hicularnavigation .Trackingalgorithmsfindhowanimageregionmovesfromoneframetothenext.Thisimpliestheexistenceofanerrorfunc tiontobeminimized ,suchasthesumofsquareddifferences (SSD)betweenthetwoimagere gions.Thiserrorfunctionistheresultofmakingthe“constantbrightnessassumption” .Yet,quiteoftenweareinterestedintrackinga…  相似文献   

14.
Based on the high frequency (HF) integrated radar cross section (RCS) calculation approach, a technique of detecting major scattering source is developed by using an appropriate arithmetic for scattering distribution and scattering source detection. For the perfect adaptability to targets and the HF of the HF integrated RCS calculation platform, this technique is suitable to solve large complex targets and has lower requirement to the target modeling. A comparison with the result of 2-D radar imaging confirms the accuracy and reliability of this technique in recognition of the major scattering source on complex targets. This technique provides the foundation for rapid integrated evaluation of the scattering performance and 3-D scattering model reconstruction of large complex targets. Project supported by the National Natural Science Foundation of China (Grant No.90305026)  相似文献   

15.
In this paper, a modified transient finite element (FE) algorithm for the performance analysis of magnetically levitated vehicles of electromagnetic type is presented. The algorithm incorporates the external power system and vehicle’s movement equations into FE model of transient magnetic field computation directly. Sliding interface between stationary and moving region is used during the transient analysis. The periodic boundaries are implemented in an easy way to reduce the computation scale. It is proved that this method can be used for both electro-motional static and dynamic cases. The test of a transformer and an EMS-Maglev system reveals that the method generates reasonable results at very low computational costs comparing with the transient FE analysis.  相似文献   

16.
Effective and robust recognition and tracking of objects are the key problems in visual surveillance systems. Most existing object recognition methods were designed with particular objects in mind. This study presents a general moving objects recognition method using global features of targets. Targets are extracted with an adaptive Gaussian mixture model and their silhouette images are captured and unified. A new objects silhouette database is built to provide abundant samples to train the subspace feature. This database is more convincing than the previous ones. A more effective dimension reduction method based on graph embedding is used to obtain the projection eigenvector. In our experiments, we show the effective performance of our method in addressing the moving objects recognition problem and its superiority compared with the previous methods.  相似文献   

17.
This novel method of Pedestrian Tracking using Support Vector (PTSV) proposed for a video surveillance instrument combines the Support Vector Machine (SVM) classifier into an optic-flow based tracker. The traditional method using optical flow tracks objects by minimizing an intensity difference function between successive frames, while PTSV tracks objects by maximizing the SVM classification score. As the SVM classifier for object and non-object is pre-trained, there is need only to classify an image block as object or non-object without having to compare the pixel region of the tracked object in the previous frame. To account for large motions between successive frames we build pyramids from the support vectors and use a coarse-to-fine scan in the classification stage. To accelerate the training of SVM, a Sequential Minimal Optimization Method (SMO) is adopted. The results of using a kernel-PTSV for pedestrian tracking from real time video are shown at the end. Comparative experimental results showed that PTSV improves the reliability of tracking compared to that of traditional tracking method using optical flow.  相似文献   

18.
Robust tracking controller for a class of uncertain nonlinear dynamical systems, which are linearizable by input-output feedback with matching uncertainties, was investigated. In this study, uniform ultimate bound or uniformly asymptotic stability of tracking errors were obtained by different choice of the control gain. A simulation to determine the effectiveness of the proposed approach showed that the control performance was better than that of VSC (Variable Structure Control). Project(69934030) supported by Natural Science Foundation of China.  相似文献   

19.
This paper presents a new approach to the extraction of a moving object from video sequence.The method is based on morphological motion filter using connected operator and a propsed new filtering criterion.The morphological motion filter aims to detect motion which is distinct from that of the background,and thereby locates independently moving physical objects in the secnes.Experiments show that the algorithm can extract object from moving backgrounds efficiently.  相似文献   

20.
This paper focuses on document clustering by clustering algorithm based on a DEnsityTree （CABDET） to improve the accuracy of clustering. The CABDET method constructs a density-based treestructure for every potential cluster by dynamically adjusting the radius of neighborhood according to local density. It avoids density-based spatial clustering of applications with noise （DBSCAN） ＇s global density parameters and reduces input parameters to one. The results of experiment on real document show that CABDET achieves better accuracy of clustering than DBSCAN method. The CABDET algorithm obtains the max F-measure value 0.347 with the root node＇s radius of neighborhood 0.80, which is higher than 0.332 of DBSCAN with the radius of neighborhood 0.65 and the minimum number of objects 6.  相似文献   

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