一种快速的InSAR图像精配准方法

Fast subpixel registration method for InSAR images

针对传统的配准方法通过对图像过采样插值来实现亚像素精度配准,但是搜索精度受限于插值单元尺寸,且计算量会随精度要求的提高而大幅增加的问题,提出了一种快速解析搜索亚像素偏移量的图像精配准方法.首先,该方法以干涉频谱信噪比为匹配测度,通过整合过采样插值和匹配测度搜索过程,将亚像素偏移量搜索过程转化为连续函数优化问题,实现了对亚像素偏移量的解析搜索,提高了配准精度;然后,采用双迭代算法对代价函数进行优化,能够快速准确地获得代价函数最大值对应的偏移量.实验结果表明,该方法不仅具有较高的配准精度,且在计算复杂度方面也有较大改善.

In conventional registration methods, image interpolation is used to extract subpixel offsets which lead to the limitation that the registration accuracy is restricted by the interpolation unit. Moreover, the computational burden is heavy when high accuracy is demanded. In order to reduce the computational load, we propose an efficient offset estimation method for interferometric synthetic aperture radar （InSAR） image subpixel registration. Firstly, a novel cost function continuously varying with offsets is established by integrating the empirical signal-to-noise ratio （SNR） and the interpolation operation. This suggests a more accurate registration since the accuracy of the estimated offsets does not depend on the interpolation unit. Secondly, an efficient bi-iterative algorithm is employed to solve the cost function in the continuous domain. The subpixel offsets associated with the maximum of the cost function can be exactly obtained with low computational complexity. Simulated and real data are tested to illustrate the good performance and computational efficiency of the proposed method.