共查询到20条相似文献,搜索用时 0 毫秒
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Jianguang Lou Tieniu Tan Weiming Hu 《Electronics letters》2002,38(18):1024-1025
A modified extended Kalman filter (EKF) is proposed for visual vehicle tracking by adding a new objective function to reduce the sensitivity of the filter to model uncertainty. Experimental results show that the performance of this approach is much better than the traditional EKF and its recent variant 相似文献
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在动态目标跟踪过程中,实用的跟踪系统要求能实时地适应运动目标的外观变化,为了解决CamShift算法在跟踪尺度变化的目标的不准确问题,本文在原算法基础上预测搜索窗口的尺寸,同时也对运动目标质心位置进行预测。实验结果表明,改进的算法对尺寸逐渐逐渐增大的目标都能自动选择合适的跟踪窗口大小。 相似文献
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《Signal Processing: Image Communication》2014,29(9):987-997
In this paper, a novel visual tracking method based on random ferns and random projection has been proposed. Instead of a binary comparison in the standard random ferns method, a subtraction is used in the proposed method. Different subtraction results are projected into a single real value by the random projection. The real value from the subtraction is more informative than a binary comparison, thus less subtractions are needed. More importantly, the proposed method has a constant memory resource requirement independent from the number of subtractions in each fern, whereas in a standard random ferns method, the requirement is an exponential relationship with the number of binary comparisons. Besides low memory requirement, our approach is also computational efficient. Experimental results demonstrate that the proposed method performs better than the standard random ferns method and some other methods, especially in memory and computing resources requirements, which are of vital importance in some embedded systems. 相似文献
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针对语音识别错误导致口语理解系统性能下降的问题,提出一种易于训练且解码快速的鉴别式口语理解方法。首先为每个语义要素建立一个二类逻辑回归模型,随后根据领域中的限制关系建立联合概率模型。在英语公开数据集DSTC2上的实验结果表明,该方法优于人工规则方法和语义元组分类器模型。 相似文献
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旋翼无人机视觉跟踪系统 总被引:3,自引:3,他引:3
设计实现了一种基于PC104计算平台的旋翼无人机自动目标跟踪系统.该系统由机载视觉子系统、地面站子系统、无线通信子系统3个部分组成.构建了完整的空地、人机交互环路.采用基于背景权重的Mean Shift目标跟踪算法,能够有效减小复杂环境背景对目标跟踪的影响.可靠性高且算法复杂度低.在室内外环境下进行的实验测试结果表明:系统在目标跟踪过程中即使遇到相似目标干扰或大面积遮挡,仍能够准确地自动跟踪目标,利用目标在图像中的位置主动引导数字云台与其保持相同运动方向,使目标尽可能处于相机中心视场范围内,验证了系统的可靠性和实时性. 相似文献
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Visual tracking for intelligent vehicle-highway systems 总被引:1,自引:0,他引:1
Smith C.E. Richards C.A. Brandt S.A. Papanikolopoulos N.P. 《Vehicular Technology, IEEE Transactions on》1996,45(4):744-759
The complexity and congestion of current transportation systems often produce traffic situations that jeopardize the safety of the people involved. These situations vary from maintaining a safe distance behind a leading vehicle to safely allowing a pedestrian to cross a busy street. Environmental sensing plays a critical role in virtually all of these situations. Of the sensors available, vision sensors provide information that is richer and more complete than other sensors, making them a logical choice for a multisensor transportation system. We propose robust detection and tracking techniques for intelligent vehicle-highway applications where computer vision plays a crucial role. In particular, we demonstrate that the controlled active vision framework can be utilized to provide a visual tracking modality to a traffic advisory system in order to increase the overall safety margin in a variety of common traffic situations. We have selected two application examples, vehicle tracking and pedestrian tracking, to demonstrate that the framework can provide precisely the type of information required to effectively manage the given traffic situation 相似文献
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In the past years, discriminative methods are popular in visual tracking. The main idea of the discriminative method is to learn a classifier to distinguish the target from the background. The key step is the update of the classifier. Usually, the tracked results are chosen as the positive samples to update the classifier, which results in the failure of the updating of the classifier when the tracked results are not accurate. After that the tracker will drift away from the target. Additionally, a large number of training samples would hinder the online updating of the classifier without an appropriate sample selection strategy. To address the drift problem, we propose a score function to predict the optimal candidate directly instead of learning a classifier. Furthermore, to solve the problem of a large number of training samples, we design a sparsity-constrained sample selection strategy to choose some representative support samples from the large number of training samples on the updating stage. To evaluate the effectiveness and robustness of the proposed method, we implement experiments on the object tracking benchmark and 12 challenging sequences. The experiment results demonstrate that our approach achieves promising performance. 相似文献
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Markow M.S. Rylander H.G. III Welch A.J. 《IEEE transactions on bio-medical engineering》1993,40(12):1269-1281
Conventional retinal laser photocoagulation is presently performed by an ophthalmologist manually aiming a low-power laser beam at a desired site and firing a high-power laser for a preselected interval of time. To automate this process a retinal tracker must acquire a target, track small saccades, and identify loss of track during a large saccade. The authors successfully implemented a real-time algorithm that used a simple computer, video digitizing card, low light video camera, and fundus camera to perform rudimentary tracking on a photograph of a retina undergoing smooth circular motion. The algorithm tracked speeds up to 5 Hz, or 27°/s, which equated to the retina moving in a 525 μm diameter circle 相似文献
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A formant tracking algorithm than first forms strings of spectral peaks considering only the relative positions of the peaks and then assigns these strings to the formants according to the relative positions and lengths of the strings is presented. An example is also given. 相似文献
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概率加权质心跟踪算法研究 总被引:1,自引:3,他引:1
针对目前图像跟踪器跟踪不稳定、跟踪精度不高及不能满足实时性要求等问题,提出了一种概率加权的质心跟踪算法.该算法首先对波门内的像素进行阈值分割,摒弃灰度低于阈值的背景像素,保留目标像素的灰度值,然后计算波门内目标区域的质心.实验结果表明:基于概率加权的质心跟踪方法能够有效降低复杂背景和噪声干扰,增强跟踪系统的抗干扰能力,减少传统跟踪系统中使用大量灰度梯度值带来的巨大计算量,从而提高跟踪器的精度和稳定性.创新点在于通过引入概率加权的方法,在计算初始时刻的目标质心时使用贝叶斯概率作为权重,而没有设置离散的阈值来分辨目标,减少了传统跟踪系统中使用大量灰度梯度值产生的计算复杂度. 相似文献
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A novel recursive least squares (RLS) type algorithm with a selfperturbing action is devised. The algorithm possesses a fast tracking capability in itself because its adaptation gain is automatically revitalised through perturbation of the covariance update dynamics by the filter output error square when it encounters sudden parameter changes. Furthermore, the algorithm converges to the true parameter values in stationary environments.<> 相似文献
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Fast parameter tracking RLS algorithm with high noise immunity 总被引:1,自引:0,他引:1
A recursive least squares (RLS) based fast parameter tracking algorithm with high noise immunity is proposed. The fast parameter tracking capability of the algorithm is achieved by perturbing the covariance matrix update equation whenever the signal model parameters change. Since the perturbing terms depends on the auto- and crosscorrelations of the signal and algorithm outputs, the proposed algorithm is very robust with respect to noise. The efficiency of the algorithm has been verified by Monte-Carlo simulations.<> 相似文献
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This paper presents a new adaptive controller for visual tracking control of a robot manipulator in 3D general motion with a fixed camera whose intrinsic and extrinsic parameters are uncalibrated. In addition to camera parameters, the feature positions are also assumed unknown. Based on the fact that the unknown parameters appears linearly in the closed-loop dynamics of the system if the depth-independent interaction matrix is adopted to map the image errors onto the joint space of the manipulator, a new adaptive algorithm was developed to estimated the unknown parameters on-line. With a full consideration of dynamic responses of the robot manipulator, the Lyapunov method is employed to prove asymptotic convergence of the image errors. Simulation and experiment results are used to demonstrate the performance of the proposed approach. 相似文献