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基于自适应滤波的宽带多信道校准技术研究 总被引:1,自引:1,他引:0
基于自适应滤波的自适应均衡技术在通信、雷达中已得到大量应用,这里对基于自适应均衡的宽带多信道校准算法进行了研究,利用自适应滤波原理综合出一个数字滤波器,对各信道的增益失配与相移失配进行精确的通道均衡补偿,该方法解决了电子战多通道接收机之间的信道校准问题。其中给出了仿真结果,验证了算法的有效性,并且采用FPGA或DSP实现数字滤波器是一项成熟的技术,所以通过设计特定的数字滤波器来实现宽带多信道的校准在工程上是可实现的。 相似文献
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本文介绍了一种实际散斑模式的数学模型和噪声统计模型,并提出了一种针对这种模型的自适应次优滤波方法。文中在分析了散斑模式及其噪声性质的基础上,利用其局部方向性特征,结合最优线性滤波器和非线性滤波器的特点,对线性最小均方误差滤波器进行了自适应逼近。实验结果表明,对散斑模式而言,本文的滤波方法与其它常用的图象滤波方法相比,具有更好的去噪和边缘保护性能,并且具有较好的滤波韧性。 相似文献
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介绍了利用中值滤波进行背景预测和背景抑制的基本原理,分析了局部中值滤波和局部最大中值滤波器处理图像的特点.根据这些特点,设计了一种能充分利用两种滤波器优越性的局部自适应中值滤波器.实验证明,利用这种滤波方法进行背景抑制具有处理速度快,滤波效果好的特点. 相似文献
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本文介绍了一种实际散斑模式的数学模型和噪声统计模型,并提出了一种针对这种模型的自适应次优滤波方法。文中在分析了散斑模式及其噪声性质的基础上,利用其局部方向性特征,结合最优线性滤波器和非线性滤波器的特点,对线性最小均方误差滤波器进行了自适应逼近,实验结果表明,对散斑模式而言,本文的滤波方法与其它常用的图象滤波方法相比,具有更好的去噪和边缘保护性能,并且具有较好的滤波韧性。 相似文献
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本文结合自适应滤波技术在地面监视雷达信号处理中的工程应用,提出一种利用自相关法实时估计杂波谱参量,并根据统计参量自适应控制滤波器的方法.采用门限判决法,改善了杂波空域分布不均匀和目标引入对杂波谱参量估计带来的误差.文中特别对自适应滤波技术的实际工程应用问题进行分析讨论.经理论分析和计算模拟论证了该方法的正确性和可行性.最后结合工程实践,给出采用TMS32020数字信号处理器实现杂波谱参量估计和自适应控制滤波器的方案设想. 相似文献
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提出了一种基于改进变步长自适应滤波的密集假目标干扰抑制方法。该方法首先采用stretch去斜处理,消去信号的二次项,并在频域上分离目标回波与干扰,从而得到频率不同的信号分量;然后用基于类箕舌线函数的变步长自适应滤波方法,对stretch处理后的回波信号滤波;最后对消密集假目标干扰,将对消后的信号作逆stretch处理恢复目标回波。所提出的类箕舌线函数调节自适应滤波方法中的步长,能有效地抑制距离目标回波较近的假目标干扰。仿真结果表明,改进变步长自适应滤波方法在目标回波与干扰时延差较小时,也可有效地对回波信号滤波,干扰对消效果明显;与基于定步长的滤波方法相比,所提方法在信干比较低的环境下仍具有良好的鲁棒性,并能有效抑制密集假目标干扰。 相似文献
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Izzetoglu M Devaraj A Bunce S Onaral B 《IEEE transactions on bio-medical engineering》2005,52(5):934-938
We present a Wiener filtering based algorithm for the elimination of motion artifacts present in Near Infrared (NIR) spectroscopy measurements. Until now, adaptive filtering was the only technique used in the noise cancellation in NIR studies. The results in this preliminary study revealed that the proposed method gives better estimates than the classical adaptive filtering approach without the need for additional sensor measurements. Moreover, this novel technique has the potential to filter out motion artifacts in functional near infrared (fNIR) signals, too. 相似文献
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An adaptive smoothing technique for speckle suppression in medical B-scan ultrasonic imaging is presented. The technique is based on filtering with appropriately shaped and sized local kernels. For each image pixel, a filtering kernel, which fits to the local homogeneous region containing the processed pixel, is obtained through a local statistics based region growing technique. The performance of the proposed filter has been tested on the phantom and tissue images. The results show that the filter effectively reduces the speckle while preserving the resolvable details. The simulation results are presented in a comparative way with two existing speckle suppression methods. 相似文献
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The application of two-dimensional (2D) signal processing to data collected in airborne laser bathymetry is investigated. Specifically, a type of 2D filter for the suppression of impulsive noise in irregularly-spaced data based on order-statistics filtering is developed. An algorithm which incorporates this type of filter along with a sophisticated 2D interpolation technique is constructed to automate the filtering process. An adaptive 2D filtering technique that can be applied to raw bathymetric profiles to remove wideband noise is then discussed. The results obtained show that each type of filtering enhances the accuracy of bathymetric measurement quite significantly 相似文献
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基于模数的干涉相位自适应中值滤波法 总被引:1,自引:0,他引:1
为了改善对干涉相位噪声的抑制效果而又确保有用相位跳变信息不被滤除,该文首先研究了模数滤波算法,并提出了一种基于最短子区间搜索的干涉相位模数估计算子对其进行改进,在进一步分析模数估计参数与相位分辨率之间关系的基础上,提出了一种局部相位中心随干涉相位质量自适应变化的中值滤波方法。该方法不仅克服了模数滤波导致的条纹边缘模糊问题,还解决了传统空域滤波进行一致性处理所造成的过滤波和欠滤波问题,而且具有较高的运算效率。最后通过对仿真和实测TerraSAR–X数据的处理和分析,验证了该方法的有效性。 相似文献
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基于LMS算法的自适应滤波器仿真实现 总被引:1,自引:0,他引:1
为了达到最佳的滤波效果,使自适应滤波器在工作环境变化时自动调节其单位脉冲响应特性,提出了一种自适应算法:最小均方算法(LMS算法)。这种算法实现简单且对信号统计特性变化具有稳健性,所以获得了极为广泛的应用。针对用硬件实现LMS算法的自适应滤波器存在的诸多缺点,采用Matlab工具对基于LMS算法的自适应滤波器进行了仿真试验。仿真结果表明,应用LMS算法的自适应滤波器不仅可以实现对信号噪声的自适应滤除,还能用于系统识别。 相似文献
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Two fast least-squares lattice algorithms for adaptive nonlinear filters equipped with bilinear system models are presented. The lattice filter formulation transforms the nonlinear filtering problem into an equivalent multichannel linear filtering problem, thus using multichannel lattice filtering algorithms to solve the nonlinear filtering problem. The computational complexity of the algorithms is an order of magnitude smaller than that of previously available methods. The first of the two approaches is an equation error algorithm that uses the measured desired response signal directly to compute the adaptive filter outputs. This method is conceptually very simple, but results in biased system models in the presence of measurement noise. The second is an approximate least-squares output error solution; the past samples of the output of the adaptive system itself are used to produce the filter output at the current time. Results indicate that the output error algorithm is less sensitive to output measurement noise than the equation error method 相似文献