共查询到20条相似文献,搜索用时 156 毫秒
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利用宽带雷达目标电磁散射特性数据可以实现雷达目标的一维距离像,在二维像实现过程中,传统做法需要利用雷达目标电磁回波的多普勒频率以实现雷达目标的方位像.探讨了基于宽带雷达散射截面(RCS)静态数据(没有多普勒频率)的二维成像算法,突破了传统需要多普勒频移数据才能实现二维雷达像的限制.最后探讨了调整成像算法若干参数的不同成... 相似文献
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基于二维小波变换的激光成像雷达目标识别算法 总被引:1,自引:0,他引:1
提出了基于二维小波变换的激光成像雷达目标识别算法,首先对激光成像雷达目标的距离像进行二维小波变换;然后从近似分量和细节分量中提取奇异值特征,利用遗传算法对支持向量机参数进行智能优化;最后应用支持向量机对三种地面目标进行识别.仿真实验表明,该方法与直接应用距离像奇异值特征进行识别的方法相比,在高载噪比20dB时的平均识别... 相似文献
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首先介绍了多普勒雷达层析成像的原理及该成像方法的极限分辨率理论推导,并通过仿真获得了单频信号的点目标扩展函数(PSF),验证了该成像方法在单频条件下的理论极限分辨率为波长的四分之一.然后,介绍了中物院构建的662GHz单频雷达系统,并针对该实验系统设计了基于卷积反投影的多普勒雷达层析成像算法.最后,通过实验在太赫兹频段验证了多普勒雷达层析成像的有效性,并利用测量获得的360°全姿态回波信号数据给出了分辨率优于1 cm的成像结果. 相似文献
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针对高分辨力雷达扩展目标回波模拟,文中设计并实现了一种高分辨力雷达扩展目标模拟系统。建立了一维距离像目标、二维面目标、三维体目标的目标回波模型,结合宽带射频接收机技术、大瞬时带宽基带回波信号产生技术、目标RCS(Radar Cross Section)数据获取与调制技术以及宽带捷变频率合成器等关键技术完成了高分辨力雷达扩展目标模拟系统的设计与实现。使用该系统对某典型战斗机目标进行了射频仿真和二维成像处理,并将射频仿真和二维成像处理结果与使用RadBase仿真软件对该典型战斗机目标的仿真结果进行对比,验证了该系统的有效性。验证结果表明,该系统的射频仿真二维成像处理结果和RadBase仿真软件的仿真结果基本一致。 相似文献
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条纹管激光成像雷达水下探测成像研究进展 总被引:1,自引:0,他引:1
条纹管激光成像雷达是一种新型的闪光式激光雷达,具有大视场、高分辨率及高探测灵敏度等特性.可直接给出目标的四维像(三维几何距离像+一维强度像),是目前激光水下三维成像的主要技术之一.自主研制了一套单狭缝条纹管激光成像雷达,可实现对远距离目标成像和系统集成.在水质较浑浊的黄海海域,利用此雷迭首先完成了若干水下目标探测实验,获得不同深度及不同表面材质的目标条纹像,最大探测深度为5 m;其次完成了海表面波成像实验,获得重构后的海表面波四维像,可清晰辨别海面粗糙度及波高变化.实验结果表明:条纹管激光成像雷达在水下探测、避障及海洋波谱分析等方面有较好的应用前景. 相似文献
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逆合成孔径雷达成像中,观测目标通常具有明显的几何特性,且随目标转角的变化,其在成像平面的投影也随之变化.提出了利用Radon变换估计线性几何目标在各次"快照"的变化位置,估计雷达视线角和转角速度的方向,并对其三维位置和二维ISAR像建立映射关系,获得三维图像.由于Radon变换对直线检测具有很强的鲁棒性,该文的方法在已知目标转角模值的条件下对转角方向实现高精度估计,在此基础上可以对线性几何目标实现三维重构.仿真结果验证了算法的正确性. 相似文献
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Two-dimensional (2-D) inverse synthetic aperture radar (ISAR) imaging has been widely used in target scattering diagnosis, modeling and target identification. A major shortcoming is that a 2-D ISAR image cannot provide information on the relative altitude of each scattering center on the target. In this paper, we present an interferometric inverse synthetic aperture radar (IF-ISAR) image processing technique for three-dimensional (3-D) target altitude image formation. The 2-D ISAR images are obtained from the signature data acquired as a function of frequency and azimuthal angle. A 3-D IF-ISAR altitude image can then be derived from two 2-D images reconstructed from the measurements by antennas at different altitudes. 3-D altitude image formation examples from both indoor and outdoor test range data are demonstrated on complex radar targets. 相似文献
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Zhixi Li Papson S. Narayanan R.M. 《Geoscience and Remote Sensing, IEEE Transactions on》2008,46(5):1394-1406
Although techniques for resolution enhancement in single-aspect radar imaging have made rapid progress in recent years, it does not necessarily imply that such enhanced images will improve target identification or recognition. However, when multiple looks of the same target from different aspects are obtained, the available knowledge increases, allowing more useful target information to be extracted. Physics-based image fusion techniques can be developed by processing the raw data collected from multiple inverse synthetic aperture radar sensors, even if these individual images are at different resolutions. We derive an appropriate data fusion rule to generate a composite image containing enhanced target shape characteristics for improved target recognition. The rule maps multiple data sets collected by multiple radars with different system parameters on to the same spatial-frequency space. The composite image can be reconstructed using the inverse 2-D Fourier transform over the separated multiple integration areas. An algorithm called the Matrix Fourier Transform is proposed to realize such a complicated integral. This algorithm can be regarded as an exact interpolation such that there is no information loss caused by data fusion. The rotation centers need to be carefully selected to properly register the multiple images before performing the fusion. A comparison of the image attribute rating curve between the fused image and the spatially averaged images quantifies the improvement in the detected target features. The technique shows considerable improvement over a simple spatial averaging algorithm and thereby enhances target recognition. 相似文献
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High-resolution radar imaging using 2-D linear prediction 总被引:7,自引:0,他引:7
An algorithm for radar imaging is described. The algorithm is based on two-dimensional (2-D) linear prediction of 2-D Cartesian frequency spectra. It is shown that the algorithm provides much better resolution than the ISAR image obtained using a 2-D inverse Fourier transform. The algorithm is especially useful for imaging targets using small-bandwidth RCS data over limited aspect angle regions 相似文献
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ISAR imaging for three-dimensional rotation targets based on adaptive Chirplet decomposition 总被引:1,自引:1,他引:0
In this paper, a new algorithm of inverse synthetic aperture radar (ISAR) imaging for three-dimensional (3-D) rotation targets
is presented. The characteristic of the received signal when the target has 3-D rotation is studied, and it is approximated
as multi-component amplitude modulated and frequency modulated (AM–FM) signal. Then a new algorithm for the adaptive Chirplet
decomposition is presented to analyze the AM–FM signal, and the high quality instantaneous ISAR images are obtained based
on the Range-Instantaneous-Doppler (RID) algorithm. The results of simulated and real data demonstrate the effectiveness of
the method proposed. 相似文献
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提出了采用步进频率结合平面扫描的THz雷达近场成像系统设计方案,基于宽带全息成像原理,可以实现三维高分辨率近场成像。采用多通道收发探头阵列缩短机械扫描行程,提高成像速度。给出了基于快速傅里叶变换(Fast Fourier Transform,FFT)和Stolt插值的三维图像重建算法,成像理论分辨率与波长相当。利用THz矢量网络分析仪和辅助设备,搭建了0.215~0.33 THz成像试验装置,完成了对多层金属-泡沫目标三维成像,成像分辨率达到预期水平,验证了系统设计和三维图像重建算法的正确性。 相似文献
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3-D radar imaging using range migration techniques 总被引:8,自引:0,他引:8
Lopez-Sanchez J.M. Fortuny-Guasch J. 《Antennas and Propagation, IEEE Transactions on》2000,48(5):728-737
An imaging system with three-dimensional (3-D) capability can be implemented by using a stepped frequency radar which synthesizes a two-dimensional (2-D) planar aperture. A 3-D image can be formed by coherently integrating the backscatter data over the measured frequency band and the two spatial coordinates of the 2-D synthetic aperture. This paper presents a near-field 3-D synthetic aperture radar (SAR) imaging algorithm. This algorithm is an extension of the 2-D range migration algorithm (RMA). The presented formulation is justified by using the method of the stationary phase (MSP). Implementation aspects including the sampling criteria, resolutions, and computational complexity are assessed. The high computational efficiency and accurate image reconstruction of the algorithm are demonstrated both with numerical simulations and measurements using an outdoor linear SAR system 相似文献
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Mei Yan Liang Cun Lin Zhang Ran Zhao Yue Jin Zhao 《Journal of Infrared, Millimeter and Terahertz Waves》2014,35(9):780-789
High resolution inverse synthetic aperture radar (ISAR) imaging is demonstrated by using a 0.22 THz stepped-frequency (SF) imaging radar system. The synthesis bandwidth of the terahertz (THz) SF radar is 12 GHz, which are beneficial for high resolution imaging. The resolution of ISAR image can reach centimeter-scale with the use of Range-Doppler algorithm (RDA). Results indicate that high resolution ISAR imaging is realized by using 0.22THz SF radar coupled with turntable scanning, which can provide foundations for further research on high-resolution radar image in the THz band. 相似文献
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在对复杂运动目标进行逆合成孔径雷达成像时,由于转动矢量随时间而变化,回波信号中会引入一个与散射点位置有关的相位误差,无法用通常的相位补偿方法进行校正,应用距离-多普勒算法获得的ISAR(Inverse Synthetic Aperture Radar)像会变得模糊.本文分析了目标转动矢量变化使得ISAR像模糊的内在原因,给出了目标三维转动状态下的ISAR信号形式,并基于散射点信号的特点提出了一种复杂运动目标的ISAR成像算法.该算法不仅适用于转动矢量方向不变的非均匀转动目标,而且对于转动矢量方向缓慢变化的目标,算法仍然能够有效地提高ISAR成像的质量.仿真试验结果表明了该算法的有效性. 相似文献
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