一种使用灰度梯度提取合成孔径雷达图像灰度边界的方法

在合成孔径雷达数字成像的多级成像和合成孔径雷达图像的许多应用中,往往需要提取合成孔径雷达图像的灰度边界特征。人们对于由可见光或红外成像系统获得的普通图像的灰度边界提取已经进行了很多研究。使用灰度梯度提取普通图像的灰度边界非常有效,得到了广泛的应用.但由于在合成孔径雷达图像中存在严重的相干斑噪声,有人认为使用灰度梯度提取合成孔径雷达图像的灰度边界得不到好的结果。在本文中,我们考虑到合成孔径雷达图像的特性,给出了一种比较理想的提取合成孔径雷达图像的灰度边界的方法。这种方法使用相对平均灰度梯度,并且把检测与跟踪结合起来。     

幂迭代超分辨率快速算法

本文提出了一种阵列信号超分辨率快速算法,并分析了它的收敛速度。这种算法基于协方差矩阵的特征值平移和矩阵的幂迭代,而不需要矩阵求逆。它的收敛速度快,一般只需几次迭代就能收敛,且算法结构简单,易于实现。     

特征值平移超分辨率算法

本文分析了逆幂迭代算法的收敛速度。为了克服逆幂迭代算法矩阵求逆的过程,提出了特征值平移幂迭代算法,并分析了它的收敛速度,给出了计算机模拟结果。     

回归相关神经网络的分析与改进

本文分析了回归相关神经网络容量与动态范围之间的关系,指出在一定条件下,回归相关神经网络具有很高的存储容量。最后给出了几种改进网络性能的方案。     

SVD在二维谱估计中的应用

本文提出将某些一维近代谱估计技术应用于二维谱估计问题的一种新方法,其基本思想是在最小二乘意义下求自相关矩阵的最佳可分近似,从而将二维谱估计问题化为一维谱估计问题来解决。文中证明了在最小二乘意义下求矩阵的最佳可分近似等价于利用奇异值分解(SVD)求矩阵的可分表示。文末给出了一组计算机模拟实验结果。     

A LUMINANCE EDGE EXTRACTION METHOD USING GRADIENT OF GRAY LEVEL FOR SYNTHETIC APERTURE RADAR IMAGERY

In the multistage imaging processing for SAR digital imaging and applications ofSAR imagery,extraction of luminance edge for the SAR imageis often required.It is well studiedto extract the luminance edge for ordinary images,The methods using gradient are effective andcommonly used.Because of the serious noise of coherent speckle exists in SAR images,somepeople believe that edge extraction by using gradient for SAR imagery gives poor results.Inthis paper,we have derived a rather ideal method for the extraction of luminance edge for SARimagery with the consideration of the characteristics of SAR imagery.This method uses therelative average gradient and combines detection with tracking.     

带宽有限信号外推的泛函算子逼近法

依照本文提出的带宽有限信号外推的算子D逼近法,利用Taylor展开式对逆算子1/D作逼近,揭示了传统的Papoulis方法收敛慢的本质原因。而采用文中提出的另一新的外推方法——相应于用Tchebycheff展开式逼近逆算子1/D,则可获得快得多的收敛速度。     

环结构神经网络及其互联想性能

本文提出了一种称为环结构神经网络(LANN)模型及其学习算法。它能像Hopfield网络,双向联想记忆(BAM)网络和其它类似网络一样工作,特别是它能执行多类样本之间的互联想记忆。理论分析和计算机模拟都证明LANN具有很好的收敛性,是一种有效的网络结构。最后本文给出了计算机模拟结果。     

TWIDDLE FACTOR MERGED FREQUENCY-DECIMAL FFT ALGORITHM——A NEW EXPLANATION OF THE RCFA

Merging the twiddle factors in two neighbouring stages for the frequency-declmal FFTalgorithm,we can obtain the twiddle factor merged frequency-decimal FFT algorithm.The result is exactlythe same as that of the Recursive Cydotomic Factorization Algorithm(RCFA)derived by Martens(1984)byuse of the theory of polynomial algebra.So it has the advantages of simple stureture and high efficiency incomputation.It is much easier to be understood and implemented by engineers than RCFA,and it is also easyto be generalized to the case of time-decimal FFT.     

TWIDDLE FACTOR MERGED TIME-DECIMAL FFT ALGORITHM AND THE SOFTWARE IMPLEMENTATION FOR TWIDDLE FACTOR MERGED FFT ALGORITHM

Martens proposed a highly efficient and simply formed DFT algorithm——RCFA,whose efficien-cy is comparable with that of WFTA or that of PFA,and whose structure is similar to that of FFT.Theauthors have proved that,in the case of radix 2,the RCFA is exactly equivalent to the twiddle factor mergedfrequency-decimal FFT algorithm.The twiddle factor merged time-decimal FFT algorithm is providedin this paper.Thus,in any case,the FFT algorithm used currently can be replaced by the more efficientalgorithm——the twiddle factor merged FFT algorithm,with exactly the same external property and thesimilar internal structure.Also in this paper,the software for implementing the twiddle factor merged FFTalgorithm(TMFFT)is provided.