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991.
针对单一的CamShift跟踪算法在目标发生遮挡时非常容易致使跟踪目标失败的问题,本文提出了一种基于CamShift和Kalman预测的跟踪算法。首先,采用帧间差分阈值法来快速、精确地检测和提取出运动目标;然后,通过在CamShift算法中使用运动目标的颜色特征,在图像序列中找到运动目标的所在位置和大小;最后,使用Kalman滤波预测目标的位置,进而有效地解决了背景中大面积相同颜色的干扰和目标部分被遮挡等问题。用无线遥控车完成了运动目标的跟踪实验,实验证明结合CamShift算法和Kalman预测滤波能实时、准确地跟踪目标。 相似文献
992.
非对称逆布局模型(NAM)适用于图像模式、语音模式、文本模式、视频模式的表示,是一个通用的模式表示模型。图像表示是计算机图形学、计算机视觉、机器人、图像处理和模式识别等领域里的一个重要问题。借助于三角形和正方形Packing问题的思想,本文提出了一种基于三角形和正方形的NAM灰度图像表示方法,简称NAMTS表示方法。给出了灰度图像的NAMTS表示算法,并对其存储结构和总数据量进行了详细分析。理论分析和实验结果表明:与经典的基于线性四元树的表示方法相比,基于三角形和正方形的NAM灰度图像表示方法能更有效地减少子模式数和数据存储空间,是灰度图像的一种良好的表示方法。 相似文献
993.
994.
995.
State feedback control of continuous-time T-S fuzzy systems via switched fuzzy controllers 总被引:1,自引:0,他引:1
This paper studies the problem of state feedback control of continuous-time T-S fuzzy systems. Switched fuzzy controllers are exploited in the control design, which are switched based on the values of membership functions, and the control scheme is an extension of the parallel distributed compensation (PDC) scheme. Sufficient conditions for designing switched state feedback controllers are obtained with meeting an H∞ norm bound requirement and quadratic D stability constraints. It is shown that the new control design method provides less conservative results than the corresponding ones via the parallel distributed compensation (PDC) scheme. A numerical example is given to illustrate the effectiveness of the proposed method. 相似文献
996.
Temporal persistence and stability of surface soil moisture in a semi-arid watershed 总被引:2,自引:0,他引:2
Satellite soil moisture products, such as those from Advanced Microwave Scanning Radiometer (AMSR), require diverse landscapes for validation. Semi-arid landscapes present a particular challenge to satellite remote sensing validation using traditional techniques because of the high spatial variability and potentially rapid rates of temporal change in moisture conditions. In this study, temporal stability analysis and spatial sampling techniques are used to investigate the representativeness of ground observations at satellite scale soil moisture in a semi-arid watershed for a long study period (March 1, 2002 to September 13, 2005). The watershed utilized, the Walnut Gulch Experimental Watershed, has a dense network of 19 soil moisture sensors, distributed over a 150 km2 study region. In conjunction with this monitoring network, intensive gravimetric soil moisture sampling conducted as part of the Soil Moisture Experiment in 2004 (SMEX04), contributed to the calibration of the network for large-scale estimation during the North American Monsoon System (NAMS). The sensor network is shown to be an excellent estimator of the watershed average with an accuracy of approximately 0.01 m3/m3 soil moisture. However, temporal stability analysis indicated that while much of the network is stable, the soil moisture spatial pattern, as represented by mean relative difference, is not replicated by the network mean relative difference pattern. Rather, the network is composed of statistical samples. Geophysical aspects of the watershed, including topography and soil type are also examined for their influence on the soil moisture variability and stability. Soil type, as characterized by bulk density, clay and sand content, was responsible for nearly 50% of the temporal stability. Topographic effects were less important in defining representativeness and stability. 相似文献
997.
998.
The problem of stabilizing a second-order SISO LTI system of the form , y=Cx with feedback of the form u(x)=v(x)Cx is considered, where v(x) is real-valued and has domain which is all of . It is shown that, when stabilization is possible, v(x) can be chosen to take on no more than two values throughout the entire state-space (i.e., v(x){k1,k2} for all x and for some k1,k2), and an algorithm for finding a specific choice of v(x) is presented. It is also shown that the classical root locus of the corresponding transfer function C(sI-A)-1B has a strong connection to this stabilization problem, and its utility is demonstrated through examples. 相似文献
999.
A new likelihood based AR approximation is given for ARMA models. The usual algorithms for the computation of the likelihood of an ARMA model require O(n) flops per function evaluation. Using our new approximation, an algorithm is developed which requires only O(1) flops in repeated likelihood evaluations. In most cases, the new algorithm gives results identical to or very close to the exact maximum likelihood estimate (MLE). This algorithm is easily implemented in high level quantitative programming environments (QPEs) such as Mathematica, MatLab and R. In order to obtain reasonable speed, previous ARMA maximum likelihood algorithms are usually implemented in C or some other machine efficient language. With our algorithm it is easy to do maximum likelihood estimation for long time series directly in the QPE of your choice. The new algorithm is extended to obtain the MLE for the mean parameter. Simulation experiments which illustrate the effectiveness of the new algorithm are discussed. Mathematica and R packages which implement the algorithm discussed in this paper are available [McLeod, A.I., Zhang, Y., 2007. Online supplements to “Faster ARMA Maximum Likelihood Estimation”, 〈http://www.stats.uwo.ca/faculty/aim/2007/faster/〉]. Based on these package implementations, it is expected that the interested researcher would be able to implement this algorithm in other QPEs. 相似文献
1000.