利用序列ISAR图像获取空间目标3-D信息的方法

如何从空间目标序列性二维(2-D,Two-Dimentional)逆合成孔径雷达(ISAR,Inverse Synthetic Aperture Radar)成像获取目标的三维(3-D)信息,是目标特征自动识别(ATR,Automatic Target Recognition)技术的重要研究课题。利用双向射线跟踪(BART,Bidirectional Analytic Ray Tracing)方法,计算连续多角度观测条件下空间目标的电磁散射数据,并由此获取空间目标的ISAR序列2-D图像。再利用KLT(Kanade-Lucas-Tomasi)特征跟踪算法,跟踪提取2-D序列ISAR图像中的特征点(强散射点),获得其2-D坐标。然后,基于正交因式分解法(OFM,Orthographic Factorization Method),计算强散射点的3-D坐标,获取空间目标的3-D信息。通过简单六棱柱模型,验证重构算法的精度;并以ENVISAT卫星模型为例,给出强散射点的3-D重构结果。结果表明,本文对空间目标3-D信息获取方法能有效地从ISAR序列2-D图像中重构目标的三维信息。

3-D Information Reconstruction of a Space Target from 2-D ISAR Image Sequence

To monitor a space object in ISAR (Inverse Synthetic Aperture Radar) technology,how to extract 3-D information from 2-D imaging is an interesting challenge in ATR (Automatic Target Recognition).A numerical approach,so\|called the Bidirectional Analytic Ray Tracing (BART) method,is first employed to numerically calculate the scattering of a complex object in space,e.g.an Envisat model under different angular positions.And then,the sequence of 2\|D ISAR imaging with angular positions is produced.Kanade-Lucas-Tomasi (KLT) feature tracker is adopted for feature extraction and matching among consecutive ISAR images.3-D positions of featured points are estimated by the orthographic factorization method (OFM).The ISAR image sequence of a simple hexagonal frustum model is simulated firstly.Then,3-D position of corner points are estimated and the result shows good accuracy.Simulated ISAR image sequence of Envisat satellite is taken as an example.The results show that 3-D shape information can be properly acquired from 2-D ISAR image sequence.