改进轮廓波变换的ISAR信号超分辨成像方法

ISAR Super-Resolution Imaging Method Based on Improved Contourlet Transform

为了克服由于实测数据有限、逆合成孔径雷达(ISAR)成像分辨率低的问题,提出了一种基于改进轮廓波变换(CT)的ISAR回波信号超分辨成像方法.该方法首先采用非下采样的轮廓波分解来实现信号不变尺度下不同方向的高频成分提取;然后将不同方向的高频信息与原始回波信息一同构建为CT变换的分解层;最后借助轮廓波重构变换技术实现ISAR回波信号的尺度拓展,进而实现超分辨成像.与用插值方法进行信号尺度拓展后成像相比,该方法更能反映空中目标雅克42型飞机雷达图像细节信息,提高成像质量,从而验证了该方法的有效性.

Considering the poor imaging caused by limited inverse synthetic aperture radar（ISAR） echo data of real target,a new super-resolution algorithm based on improved contourlet transform（CT） is proposed to achieve ISAR super-resolution imaging.It is realized by nonsubsampled contourlet decomposition to extract high-frequency information from ISAR echo data in different directions based on scale invariant feature.Then decomposition levels of CT are constructed with the high-frequency information in different directions and raw echoed data.Contourlet reconstruction is used to expand ISAR echo signal in scale.It shows that ISAR image using this method will be with great advantages of reflecting YAK42 airplane information in detail and improving imaging quality over that using interpolation method,which validates the validity of this method.