利用对比度最大化实现SAR图像自聚焦

A Novel Autofocus Algorithm for SAR Imagery by Contrast Maximization

以对比度作为衡量图像聚焦程度的标准 ,研究了一种新颖的 SAR图像自聚焦算法。该方法从图像域出发 ,通过在距离压缩相位历史域引入相位误差模型 ,从而改变聚焦直至图像对比度最大 ,完成相位误差的校正。对比度最大化算法的突出优点是无须在图像域分离出强点目标 ,因而特别适用于无任何明显特征的图像。仿真及实测数据处理结果证明了该方法的可行性。

Considering the image contrast as a measurement of the degree of the image focus, a novel autofocus algorithm for Synthetic Aperture Radar (SAR) imagery is presented in this paper. The method, which starts right in with complex phase-degraded SAR imagery, after phase errors model is introduced into the range-compressed phase-history domain, carries out phase errors correction by changing the focus until the image contrast is maximized. It is a pronounced merit for contrast maximization algorithm not to isolate prominent point in image domain. So it is especially suitable for the class of image without specific target. Simulation and the processing results of real data show the feasibility of the proposed method.