高应力硬脆玄武岩微裂隙分布及破裂发展辨识

白鹤滩水电站区域构造地应力高,玄武岩坚硬性脆、隐微裂隙发育,地下厂房开挖过程顶拱浅层应力型开裂和深层破裂特征明显,传统的声波、钻孔电视测试和变形监测等方法难以精确获取岩体微破裂裂隙分布特征及高应力破裂发展特征信息。采用高精度超声波成像综合测试系统新方法,对厂房顶拱应力破裂破坏显著区域进行了多次重复测试。测试成果揭示：① 厂房顶拱上方岩体赋存的裂隙面倾角以陡倾角为主,优势倾角范围为45.98°~52.06°;裂隙面的倾向为NWW向,优势倾向范围为276.36°~292.01°,裂隙面倾角和倾向随深度变化不明显。② 顶拱浅层围岩破裂裂纹集中区一般在3.50~4.25 m的深度范围内,围岩深部诱发破裂裂纹区主要分布在9.68~10.11,16.12~16.32,21.45~21.77 m范围。③ 局部岩体受顶拱应力场不断调整演化作用,出现岩体破裂随时间加剧的现象。该成果高精度地辨识了玄武岩不同深度微破裂裂隙面分布特征、深度范围和应力破裂发展特点,对研究高应力硬脆玄武岩力学特性和响应机理提供了坚实基础资料,为工程开挖施工和动态支护设计发挥了重要支撑作用。     

2-D Doppler shift-frequency intermittent sampling jamming against SAR

To generate the false targets in the desired area accurately, a novel two dimensional(2-D) intermittent sampling jamming algorithm against synthetic aperture radar(SAR) is presented. The intercepted radar signals are processed via 2-D intermittent sampling and Doppler shift-frequency and retransmitted to radar. Hence, the false target-lattice emerges in the specified area. The generation mechanism, position and distribution characteristics of false target-lattice are discussed. Meanwhile, the reason for the asymmetric amplitude of the target false-lattice and the modulation factor of energy compensation are presented. The correctness of theoretical analysis and validity of the proposed algorithm are verified through simulation experiments. Compared with conventional methods, the critical requirement of the jammer position can be reduced by the proposed method.     

New soft morphological parameterized symmetric logarithmic image processing filtering algorithm

Synthetic Aperture Radar (SAR) imaging has the inherent random speckle noise, which seriously affects the quality of the SAR image, and it is very important to study the suppression of the speckle noise. In view of the fact that the traditional spot noise suppression method could not remove speckle noise while protecting the image texture information, a novel filtering algorithm is proposed based on the soft morphological and parameterized symmetric logarithmic image processing model. The proposed algorithm combines the flexibility of the order-statistic soft morphological operations and the characteristic of the parameterized symmetric logarithmic image processing model which establishes a parameterized symmetric structure processing part of the image, which can suppress speckle noise while protecting the texture information on the image. In order to validate the despecking performance of the proposed algorithm, we compare the effect of the filter with some of the existing filtering algorithms, and use some of the image evaluation parameters of the suppress speckle noise image to evaluate the performance of the SMPSLIP filtering algorithm. Experimental results show the effectiveness of this algorithm.     

Performance Comparison of Long-Wave Infrared Imaging Spectrometer Between Dyson Form and Offner Form

In view of the difficulties in traditional long-wave infrared imaging spectrometer which is hard to realize a high signal-to-noise ratio and miniaturization as well under the weak remote sensing signal,Offner convex grating spectrometer and Dyson concave grating spectrometer,both having concentric structure,are designed and analyzed in the band of 8-12 μm. The diffraction angle expressions of the two spectrometers are obtained and the diffraction characteristics are acquired. Both of the spectrometers are designed in Zemax environment under different F-numbers and different grating constants with the same slit,spatial resolution,spectral resolution and detector. The results show that Dyson grating spectrometer possesses the advantages of higher throughput and smaller volume, and Offner grating spectrometer possesses the advantage of more accessible material and the absence of chromatic aberration. The differences between Dyson form and Offner form show that the former is a better choice in the long-wave infrared imaging spectrometer.     

一种靶向蛋白质超声微泡的制备及表征

以氟碳气体为超声造影剂,通过接枝纳米磁性颗粒-RGD多肽,构建靶向蛋白质超声微泡,制备一种可同时用于超声造影和磁共振成像(MRI)的双模态造影增强剂。通过显微镜对磁性蛋白超声微泡形貌进行观察,利用红外光谱、分光光度法分析纳米磁性颗粒接枝牛血清蛋白的接枝率,并通过细胞实验评价磁性蛋白微泡的生物相容性。     

地球敏感器成像仿真与检测方法

针对地球敏感器的设计与仿真需求,研究了地球椭球成像、大气轮廓、晨昏线及背景星空成像,实现了高精度地球敏感器成像仿真;并在此基础上比较实验了圆拟合、椭圆拟合等不同地球边界拟合及地心检测算法的性能,根据系统在轨运行特点,提出了分步地球图像检测算法.一方面克服单纯圆拟合方法带来的地球扁率误差,另一方面利用轨道先验知识克服椭圆拟合过程中的长轴不稳定性.仿真实验证明,该方法有效地提高了敏感器检测精度及系统鲁棒性,并且时间复杂度低,满足在轨要求,能够有效促进各型地球敏感器的性能提升.     

基于Legendre多项式展开的双基SAR二维频域成像算法

针对任意构型双基SAR基于传统Taylor级数展开斜距方法的边缘点散焦问题,提出了一种基于Legendre正交多项式逼近的双基SAR二维频域成像算法。该算法基于对斜距函数的Legendre多项式展开推导了点目标二维频谱,解除了回波信号距离—方位的耦合,使成像处理更高效。在二维频域对场景区域的点目标采用二维频域成像算法进行成像。该算法改善了场景边缘点的聚焦效果,增加了场景边缘点的聚焦深度。理论推导和仿真结果验证了该算法的有效性和可行性。     

快照成像光谱仪快速光谱重构算法

为实现对光谱数据的快速实时处理,针对快照式傅里叶成像光谱仪,提出一种基于GPU的并行化光谱重构算法.通过分析快照式成像光谱仪的工作原理和数据特性,结合CUDA并行计算架构,对光谱重构算法可并行部分最大程度并行化,并针对并行计算中的内存分配等方面进行优化处理,实现并行化的光谱重构算法.实验结果表明:基于GPU的并行化光谱重构算法,相对CPU串行化算法,精度相同的情况下,计算效率提升了约25倍.利用GPU加速程序的并行部分,可以极大地提高光谱重构的效率,使得快照式成像光谱仪更加适用于实时测量当中.     

Multistatic passive radar imaging algorithm for the gapped aperture

Due to usually a small number of narrowband external illuminators and their uneven distribution, a single external illuminator and several receivers are used to synthetize aperture equivalently. The form of the target echo of the multistatic passive radar system is analyzed, and then the relationship of Fourier transform pair between target scattering function and the echo received by radar is deduced. Based on the prior knowledge of sparse distribution of the target, the algorithm of Compressed Sensing is used to recover the scattering coefficient of targets. Finally, the positions of receivers have been optimized by minimizing the correlation of the dictionary matrix based on minimizing the correlation coefficient of the dictionary matrix by the algorithm of Simulated Annealing (SA). Simulations show that the performance of the recovery of the image is improved significantly after optimizing.     

大场景 SAR图像舰船目标快速检测

基于SAR图像的舰船目标检测是海洋监视应用的重要方面,随着SAR图像资源的不断丰富,计算速度成为衡量舰船目标检测算法的重要指标。针对大场景SAR图像,提出一种基于分块CFAR的舰船目标快速检测算法。首先通过图像增强提高舰船目标与海洋杂波之间的对比度,然后利用差异性参数进行分块筛选,剔除不包含目标的区域,最后对待检测区域实现基于积分图的快速CFAR检测。TerraSAR_X实测数据的实验结果验证了该方法的有效性。