基于自适应匹配滤波的近场毫米波高分辨率SAR成像方法

    Near-field millimeter-wave high-resolution SAR imaging method based on adaptive matching filtering

    • 摘要: 毫米波合成孔径雷达(SAR)在对近场目标成像时,目标所在距离门的选取直接影响到成像效果;此外,近场条件下雷达的回波信号会受到高旁瓣的调制,目标边缘的回波信息被掩盖,导致边缘成像模糊。针对上述问题,本文提出了一种结合模拟退火算法(SA)和粒子群算法(PSO)的自适应匹配滤波近场成像算法。首先,引入目标距离、Kaiser窗参数和插值因子 作为粒子位置参数的三维解,并构建基于融合峰值信噪比、对比度和图像熵的多维度加权适应度函数进行寻优迭代;其次,针对粒子群易陷入局部解的问题,在迭代过程中引入SA算法对多维度适应度函数的权重比值进行动态调整,确定最优参数组合;最后,基于最优参数组合,建立插值因子与Lee滤波窗口尺寸的关系,自适应调节窗口大小进行噪声抑制,实现了优化匹配滤波成像。实验表明,所提方法有效提高了近场SAR成像的成像分辨率,完善了边缘信息,得到了较高质量的成像结果。

       

      Abstract: When millimeter-wave synthetic aperture radar (SAR) images near-field targets, the selection of the distance gate where the target is located directly affects the imaging effect. In addition, the echo signal of the radar in the near field will be modulated by high sidelobes, and the echo information at the edge of the target will be masked, resulting in blurred edge imaging. To solve the above problems, this paper proposes an adaptive matching filtering near-field imaging algorithm that combines simulated annealing algorithm (SA) and particle swarm optimization (PSO). Firstly, the target distance, Kaiser window parameters and interpolation factors were introduced as the three-dimensional solutions of particle position parameters, and a multi-dimensional weighted fitness function based on the fusion peak signal-to-noise ratio, contrast and image entropy was constructed for optimization iteration. Secondly, in order to solve the problem that particle swarms are easy to fall into local solutions, the SA algorithm is introduced to dynamically adjust the weight ratio of the multi-dimensional fitness function in the iterative process to determine the optimal parameter combination. Finally, based on the optimal parameter combination, the relationship between the interpolation factor and the size of the Lee filter window was established, and the window size was adaptively adjusted for noise suppression, so as to realize the optimal matching filter imaging. Experiments show that the proposed method can effectively improve the imaging resolution of near-field SAR imaging, improve the edge information, and obtain high-quality imaging results.

       

    /

    返回文章
    返回