在重航过飞行条件下,由于机载平台飞行高度和姿态不稳定导致实际飞行航迹偏离理想航迹,使得多航过影像对之间存在相对形变,尤其是在沿航线方位存在伸缩,导致同名点对应位置存在较大偏差;另外由场景地形起伏带来的图像距离向伸缩形变,也使得实现重航过图像高精度配准困难。而在相干变化检测、重轨干涉等应用中,要求对两幅或多幅图像进行亚像素级配准,以保证检测效果和后续干涉处理要求。文中首先从SAR 成像精准几何关系出发,利用地理高程信息,生成高定位精度的多航过复图像,然后通过计算和二维拟合产生主辅图像同名点位移矢量,最后将辅图像在空间开展二维重采样实现重航过SAR 图像精确配准。飞行试验结果证明了该方法的有效性。

For repeat-track condition, the relative deformation can be caused among the multiple navigable synthetic aperture radar (SAR) image pairs by the instability of the airborne platform, especially along the azimuth direction. In addition, the height of the scene makes it difficult to realize high-precision registration of the repeat-track images. In the application of coherent change detection (CCD), dual or more images are required to be registered at the sub-pixel level to ensure effective detection. In this paper, SAR imaging geometric relationship and geographic elevation information are used to improve the registration accuracy. The displacement vector of the control point is computed by a two-scale approach. Finally, the two-dimensional complex image warp is accomplished to get the registered images. The experiment result demonstrates the effectiveness of the proposed algorithm.

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