共查询到17条相似文献,搜索用时 125 毫秒
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基于概率假设密度滤波平滑器的检测前跟踪算法 总被引:1,自引:0,他引:1
基于概率假设密度滤波(PHD)的检测前跟踪(TBD)技术可以有效解决未知弱小多目标检测问题。PHD-TBD算法粒子权重计算受量测噪声影响明显,导致目标数估计存在起伏现象,制约了PHD-TBD算法性能。对PHD-TBD技术进行研究,引进概率假设密度滤波平滑器,提出基于平滑的PHD-TBD算法。该算法对当前帧目标数估计时,综合利用前向递推和后向平滑结果对粒子权重进行更新,在一定程度上克服了随机量测噪声的影响。通过仿真验证,该算法能够有效发现目标,准确估计目标数目和位置,性能有较大提高。 相似文献
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针对无线传感器网络多目标跟踪过程中杂波难以去除以及由数据关联复杂带来的计算复杂度高的问题,将概率假设密度滤波器应用于无线传感器网络,以更好地对多目标状态信息进行融合估计;首先,建立簇-树型无线传感器网络模型,并运用随机有限集理论对目标状态模型和传感器观测模型进行描述;然后,根据目标与节点之间的距离设置观测阈值,当传感器节点测量值小于观测阈值时,概率假设密度滤波器将实时对该组测量数据进行处理,从而实现传感器网络对目标状态的联合检测与跟踪;仿真结果表明,在无线传感器网络的多目标跟踪应用中,该算法比粒子滤波算法具有更高的跟踪效率和精度。 相似文献
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为了解决传统水下目标跟踪中目标数目估计不准确、状态估计误差增长过快的问题,提出了一种基于高斯混合概率假设滤波的水下目标跟踪算法。该算法基于双基地观测模型,采用高斯混合概率假设滤波算法处理方位和时延信息,利用粒子群算法处理多普勒频率获得矢量速度,进一步提升算法的跟踪精度。结果表明,该算法能完成在杂波环境下对目标的跟踪,相比传统的关联算法,能够有效地实现目标个数估计和抑制状态误差增长的目的。 相似文献
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基于小波概率估计的图像融合方法研究 总被引:6,自引:4,他引:2
在研究了已有的图像融合方法后,提出基于小波变换和最大似然概率估计(MLE)相综合的融合方法,利用概率估计融合模型,首先对不同的传感器图像进行小波分解,然后对相应的子带求解仿射变换参数,根据Bayes规则进行最大后验概率似然估计,得到估计子带系数,最后通过小波反变换得到融合图像.在仿射变换的假设条件下定义融合规则,更适合传感器图像具有局部相反对比度的情况,采用此方法对航空可见光图像和红外图像进行融合实验,其结果与采用其它方法进行了对比,表明该方法的有效性. 相似文献
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Hamaker三个假设条件是用连续方法解离散问题的理论基础.根据Hamaker三个假设条件,利用连续方法计算两个原子之间的相互作用力,发现作用力同经典的Lennard-Jones势所反映的作用力不一致.通过分析得出Hamaker均质材料假设条件仅适用于微观物质间距较大的范围以及数字密度随间距变化的结论;推导出数字密度随间距变化的表达式,修正了Hamaker提出的用连续方法计算微观物质间相互作用力的表达式.最后对Hamaker常数进行分析,得出Hamaker常数本身就是随物质间距变化的结论,从而对目前存在的
关键词:
Hamaker假设
数字密度
Hamaker常数
Lennard-Jones势 相似文献
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量子效率是表征负电子亲和势(NEA)光电阴极发射性能的最重要的特性参数,准确建立量子效率公式为揭示各个阴极参量对整体性能的影响以及NEA光电阴极的优化设计提供了重要的理论指导.在对NEA光电阴极体内及表面光电发射过程的分析基础上,考虑入射光子能量、表面能带弯曲区以及表面势垒对电子发射的影响,对表面逸出概率和电子衰减长度进行了修正,并利用积分法推导了NEA光电阴极的量子效率公式,其理论预测曲线与实验曲线基本一致,从而验证了修正公式的实用性.为NEA光电阴极的研究提供了有效的理论参考依据.
关键词:
负电子亲和势光电阴极
量子效率
能带弯曲区
衰减长度 相似文献
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A major advantage of the use of passive sonar in the tracking multiple underwater targets is that they can be kept covert, which reduces the risk of being attacked. However, the nonlinearity of the passive Doppler and bearing measurements, the range unobservability problem, and the complexity of data association between measurements and targets make the problem of underwater passive multiple target tracking challenging. To deal with these problems, the cardinalized probability hypothesis density (CPHD) recursion, which is based on Bayesian information theory, is developed to handle the data association uncertainty, and to acquire existing targets’ numbers and states (e.g., position and velocity). The key idea of the CPHD recursion is to simultaneously estimate the targets’ intensity and the probability distribution of the number of targets. The CPHD recursion is the first moment approximation of the Bayesian multiple targets filter, which avoids the data association procedure between the targets and measurements including clutter. The Bayesian-filter-based extended Kalman filter (EKF) is applied to deal with the nonlinear bearing and Doppler measurements. The experimental results show that the EKF-based CPHD recursion works well in the underwater passive multiple target tracking system in cluttered and noisy environments. 相似文献
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《声学学报:英文版》2016,(3)
A tracking filter algorithm based on the maneuvering detection delay is presented in order to solve the fuzzy problem of target maneuver decision introduced by the measure?ment errors of active sonar. When the maneuvering detection is unclear, two target moving hypotheses, the uniform and the maneuver, derived from the method of multiple hypothesis tracking, are generated to delay the final decision time. Then the hypothesis test statistics is constructed by using the residual sequence. The active sonar?s tracking ability of unknown prior information targets is improved due to the modified sequential probability ratio test and the integration of the advantages of strong tracking filter and the Kalman filter. Simulation results show that the algorithm is able to not only track the uniform targets accurately, but also track the maneuvering targets steadily. The effectiveness of the algorithm for real underwater acoustic targets is further verified by the sea trial data processing results. 相似文献
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提出了一种融合多平台方位观测数据的水下声学目标定位跟踪方法。该方法采用多级多假设跟踪对目标状态进行滤波和关联,第一级基于每个平台波束域检测结果独立使用多假设跟踪方法对目标方位角进行初级跟踪;第二级首先通过多平台联合似然概率估计多目标初始位置,再用多假设跟踪方法对不同平台初级跟踪的方位角航迹进行关联,最后通过关联的角度值和扩展卡尔曼滤波对多目标位置进行序贯估计。仿真结果证明,该方法能以更少计算量实现更优定位性能,优于单级多假设跟踪方法.海试数据处理结果表明,存在较多干扰的情况下,单级方法跟踪过程中丢失目标,而多级方法实现了对目标的全程跟踪,且收敛后定位误差在70m内。该方法可降低噪声干扰对数据关联及目标定位的影响,并通过多平台协同消除线阵的方位模糊,适用于移动多平台声学目标定位和跟踪场景。 相似文献
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A flux fluctuation theorem proposed recently [Seitaridou, et al., J. Phys. Chem. B 111 (2007) 2288] on the relative probability of direct and reverse diffusion fluxes in a non-equilibrium steady state is related here to a non-equilibrium thermodynamic potential used in extended irreversible thermodynamics. This connection allows one to provide a new derivation of the theorem, which complements the previous one, to generalize it to other fluxes, and illustrates the thermodynamic relevance of this theorem. 相似文献
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We analyze the problem of a quantum computer in a correlated environment protected from decoherence by quantum error correction using a perturbative renormalization group approach. The scaling equation obtained reflects the competition between the dimension of the computer and the scaling dimension of the correlations. For an irrelevant flow, the error probability is reduced to a stochastic form for a long time and/or a large number of qubits; thus, the traditional derivation of the threshold theorem holds for these error models. In this way, the "threshold theorem" of quantum computing is rephrased as a dimensional criterion. 相似文献
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A rigorous derivation of the optical theorem (OT) from the conservation of probability flux (CPF) is presented for scattering
on an arbitrary spherically symmetric potential inN-spatial dimensions (ND). The constructed expression for the OT is found to yield the corresponding well-known results for
two- and three-dimensional cases in a rather natural way. The Aharonov-Bohm (AB) effect is considered as a scattering event
of an electron by a magnetic field confined in an infinitely long shielded solenoid and a similar derivation is attempted
for an appropriate optical theorem. Our current understanding of the scattering theory is found to be inadequate for the purpose.
The reason for this is discussed in some detail. 相似文献