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基于三阶累积量的红外弱小运动目标检测新方法 总被引:8,自引:5,他引:3
为检测强杂波背景中的红外弱小运动目标,提出了一种基于三阶累积量的检测新方法.该方法利用图像中目标经过时像素点灰度值有起伏变化这一特点,将其看作是一种非高斯弱瞬态信号,通过构造三阶累积量对其进行检测.此三阶累积量估计中的去均值处理同时实现了背景杂波的抑制,较好地改善了信杂比(SCR),提高了单帧检测性能.实验表明,该方法能够有效地抑制强杂波背景,在SCR>1时,能可靠检测目标. 相似文献
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关联噪声和周期信号驱动的非对称双稳系统的稳态分析 总被引:2,自引:1,他引:1
运用Liouville equation和诺维科夫原理,解出了关联噪声和周期信号共同驱动的非对称双稳系统的近似福克-普朗克方程,并求解了其稳态概率密度函数.在此基础上,分析了乘性噪声强度 、加性噪声强度 、噪声间关联系数 ,周期信号振幅 、频率 以及系统非对称参数 等对稳态概率密度分布曲线的影响.结果表明:(1)噪声强度及其关联、周期信号振幅、系统非对称参数的改变均能引起稳态概率密度分布曲线单峰结构和双峰结构之间的转换,即能够诱导非平衡相变产生;(2)周期信号频率改变时,没有非平衡相变发生;(3)当系统非对称参数为零时,稳态概率密度分布曲线具有关于 的对称结构;当系统非对称参数不等于零时,其对称结构被破坏. 相似文献
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研究多径传输条件下的时延估计问题。利用三阶累积量的一维切片作为高阶统计量,结合相关算法原理,提出一种新的时延估计算法。为提高时延估计精度,对相关数据进行了加权处理。该算法可有效抑制空间相关高斯噪声或对称分布噪声,得到非高斯信号准确的时延估计。算法具有计算量小,易于实现的优点。仿真结果表明了该算法的有效性。 相似文献
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关联噪声和周期信号驱动非对称双稳系统的稳态分析 总被引:1,自引:0,他引:1
《量子电子学报》2014,(1)
运用Liouville方程和诺维科夫原理,解出了关联噪声和周期信号共同驱动的非对称双稳系统的近似福克-普朗克方程,并求解了其稳态概率密度函数。在此基础上,分析了乘性噪声强度D、加性噪声强度Q、噪声间关联系数λ,周期信号振幅A、频率Ω以及系统非对称参数r等对稳态概率密度分布曲线的影响。结果表明:1)噪声强度及其关联、周期信号振幅、系统非对称参数的改变均能引起稳态概率密度分布曲线单峰结构和双峰结构之间的转换,即能够诱导非平衡相变产生;2)周期信号频率改变时,没有非平衡相变发生;3)当系统非对称参数为零时,稳态概率密度分布曲线具有关于x=0的对称结构;当系统非对称参数不等于零时,其对称结构被破坏。 相似文献
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机动检测是多模型目标跟踪中的一个关键问题.在卡尔曼滤波中,当目标机动被噪声淹没时,传统的机动检测算法将失效,多分辨方法虽然能够有效地抑制噪声,可靠检测机动,但由于计算复杂导致严重的检测延迟,从而限制了它的应用.本文提出一种基于三阶累积量的机动检测新算法,它有效地克服了上述二者的缺陷.由于高阶累积量能够抑制高斯噪声,因此在三阶累积量域易于检测机动.同时通过采用逐点更新法,可实时进行机动检测.仿真结果表明,该算法优于传统算法和多分辨方法,特别是在低信噪比的情况下. 相似文献
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In this paper, the authors present optimal multichannel frequency domain estimators for minimum mean-square error (MMSE) short-time spectral amplitude (STSA), log-spectral amplitude (LSA), and spectral phase estimation in a widely distributed microphone configuration. The estimators utilize Rayleigh and Gaussian statistical models for the speech prior and noise likelihood with a diffuse noise field for the surrounding environment. Based on the Signal-to-Noise Ratio (SNR) and Segmental Signal-to-Noise Ratio (SSNR) along with the Log-Likelihood Ratio (LLR) and Perceptual Evaluation of Speech Quality (PESQ) as objective metrics, the multichannel LSA estimator decreases background noise and speech distortion and increases speech quality compared to the baseline single channel STSA and LSA estimators, where the optimal multichannel spectral phase estimator serves as a significant quantity to the improvements, and demonstrates robustness due to time alignment and attenuation factor estimation. Overall, the optimal distributed microphone spectral estimators show strong results in noisy environments with application to many consumer, industrial, and military products. 相似文献
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Voice Activity Detection under Rayleigh distribution 总被引:1,自引:0,他引:1
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Wireless Sensor Networks (WSN ) are mainly characterized by a potentially large number of distributed sensor nodes which collectively transmit information about sensed events to the sink. In this paper, we present a Distributed Wavelet Basis Generation (DWBG) algorithm performing at the sink to obtain the distributed wavelet basis in WSN. And on this basis, a Wavelet Transform-based Distributed Compressed Sensing (WTDCS ) algorithm is proposed to compress and reconstruct the sensed data with spatial correlation. Finally, we make a detailed analysis of relationship between reconstruction performance and WTDCS algorithm parameters such as the compression ratio, the channel Signal-to-Noise Ratio (SNR), the observation noise power and the correlation decay parameter by simulation. The simulation results show that WTDCS can achieve high performance in terms of energy and reconstruction accuracy, as compared to the conventional distributed wavelet transform algorithm. 相似文献
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This paper examines the noise and rotation resistance capacity of Hopfield Neural Network (HNN) given four corrupted traffic sign images. In the study, Signal-to-Noise Ratio (SNR), recall rate and pattern complexity are defined and employed to evaluate the recall performance. The experimental results indicate that the HNN possesses significant recall capacity against the strong noise corruption, and certain restoring competence to the rotation. It is also found that combining noise with rotation does not further challenge the HNN corruption resistance capability as the noise or rotation alone does. 相似文献
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Fan Yangyu Zhang Zhengwei Wei Xiaorong Zeng Li Wei Wei 《电子科学学刊(英文版)》2007,24(6):753-759
This paper focuses on the extraction of a harmonic signal from multiplicative and additive noises. A method is proposed in two stages: (1) to square the original discrete time series, which in- cludes both signals and noises, and form a new time series. By this means, the multiplicative noise is converted to additive noise; and (2) to filter out the noise by using existing noise removal schemes. With a large amount of simulation, experimental results demonstrated the efficiency and effective- ness of this newly developed method in terms of Signal-to-Noise Ratio (SNR) and other criteria. From the experiment, it is also found that: the two kinds of noises affect the SNR differently. In gen- eral, the SNR is not influenced by multiplicative Gaussian noise regardless of its variance. However, if both kinds of noise exist, the SNR decreases with the incensement of the Variance of Additive Noise to Multiplicative Noise Ratio (VAMNR). This analysis is also supported by simulation work. 相似文献
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In this paper, a Quadrature Amplitude Modulation (QAM) signal recognition algorithm is proposed based on amplitude distribution of the signal. The algorithm uses envelop amplitude dis-tribution information extracted by wavelet analysis to do modulation classification. It provides ro-bustness for symbol rate determination. Simulation shows that it is more effective and convenient than the recognition algorithm of likelihood function at moderate Signal-to-Noise Ratio (SNR). 相似文献
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提出了用对数正态分布描述噪声相关性偏态分布的最佳模型。首先通过理论分析和实验发现,在(0,1]区间β分布、Γ分布和对数正态分布可用于描述噪声相关性的偏态分布;然后分别利用这3种分布的概率密度函数(PDF)模拟实际的噪声相关性偏态分布曲线,曲线的形态与实际的噪声相关性偏态分布形态的相似程度的比较表明,采用对数正态分布描述噪声相关性偏态分布的效果最佳;最后利用最大熵方法证明了模型的最佳性。实验结果表明,本文提出的模型与另外两种模型相比,可使最小错误率降低70%以上。 相似文献
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该文针对多脉冲发射协同结构的分布式全相参雷达,首先建立了全相参模式下的信号模型,然后推导了输出信噪比增益(oSNRg)的解析式,并基于相干参数估计的克拉美-罗界(CRB),利用多项式拟合,获得了oSNRg上界的数值解。结果表明:增加发射天线数或脉冲数能够提高oSNRg;而增加接收天线数能否提高oSNRg取决于输入信噪比大小,输入信噪比较大时则oSNRg随之提高,较小时反而随之下降。最后的仿真实验验证了研究结论的正确性。 相似文献