斜视多角度SAR图像配准及高度估计方法研究

发布时间：2018-04-04 16:29

本文选题：多角度　切入点：圆迹SAR　出处：《山东科技大学》2017年硕士论文

【摘要】：合成孔径雷达(SAR)是一种对目标区域可全天时、全天候微波成像的雷达系统。传统直线SAR由于其目标观测角范围的限制,只能获取有限的目标信息,无法进行三维成像。相比传统SAR系统,多角度SAR可观测范围更大,可获取不同方位角度的高分辨率SAR影像,并具有三维成像能力;而且多角度SAR还可通过改变斜视角对任意区域进行探测,提高了系统灵活性。因此,多角度SAR正以其独特的系统优势,逐渐成为雷达研究领域的新热点。几何校正是图像预处理的关键技术之一,也是实现SAR影像高精度定位与识别应用的前提。在SAR影像构像模型中,目标高度是进行目标地理坐标定位的重要参数。因此,目标高度解算和目标定位及几何校正是耦合在一起的。多角度SAR可实现基于不同斜视角的高度估计,为获取目标的高精度立体信息,本文主要工作如下:(1)总结归纳多角度SAR独特的系统优势,分析SAR参数随斜视角的变化规律,并对斜视情况下的构像模型进行分析,推导得出各方位点多普勒中心及对应卫星时刻公式。(2)分析变斜视角立体测高精度的影响因素;通过仿真实验对正侧视、斜视情况下最近邻点、双线性内插法产生的误差以及其在几何校正中引入的问题进行对比分析。针对由斜视SAR引入更为复杂几何畸变问题,本文提出一种具有景间相对位置保持技术的重采样方法,通过实验验证了该方法可有效提高斜视SAR几何校正效果。(3)利用MSTAR数据集,本文采用SIFT特征向量匹配和RANSAC剔除误匹配策略,对具有一定视角范围内的两景间影像进行匹配,获取同名点坐标。(4)利用MSTAR数据集,通过同名地物点在不同角度影像中的位置偏移及视角差进行目标点高度求解实验。实验表明,测量结果接近真实值。
[Abstract]:Synthetic Aperture Radar (SAR) is a radar system with all-weather microwave imaging for target area.Traditional linear SAR can only obtain limited target information because of the limitation of the range of target observation angle, so it can not be used for 3D imaging.Compared with the traditional SAR system, the multi-angle SAR can be observed in a larger range, can obtain high-resolution SAR images with different azimuth angles, and has the ability of 3D imaging, and multi-angle SAR can detect any region by changing the oblique angle of view.The flexibility of the system is improved.Therefore, multi-angle SAR is becoming a new hotspot in radar research field because of its unique system advantages.Geometric correction is one of the key techniques of image preprocessing, and it is also the premise of high precision localization and recognition of SAR image.In the conformation model of SAR image, the target height is an important parameter to locate the geographical coordinates of the target.Therefore, target height solution is coupled with target location and geometric correction.Multi-angle SAR can realize height estimation based on different squint angles. In order to obtain high-precision stereoscopic information of target, the main work of this paper is as follows: 1) summarize the unique system advantages of multi-angle SAR, and analyze the variation of SAR parameters with squint angle.The conformation model under strabismus is analyzed, and the formula of Doppler center of each locus and corresponding satellite time is deduced. The factors influencing the accuracy of stereoscopic measurement with variable angle of view are analyzed.In strabismus, the errors caused by bilinear interpolation and the problems introduced in geometric correction are compared and analyzed.In view of the more complicated geometric distortion problem introduced by squint SAR, this paper presents a resampling method with the technique of relative position holding between scenes. The experimental results show that this method can effectively improve the geometric correction effect of squint SAR.In this paper, SIFT feature vector matching and RANSAC eliminating mismatch strategy are used to match the images between two scenes in a certain range of visual angle, and the coordinate of the same name points is obtained. (4) MSTAR data set is used.The target height calculation experiment is carried out by the position deviation and angle difference of the same name ground object in different angle image.The experimental results show that the measured results are close to the real values.
【学位授予单位】：山东科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P237

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