基于图像对比度的舰船目标成像算法

针对舰船目标ISAR成像时舰船随机摆动对于成像质量的影响,提出了一种同时基于多普勒中心估计和图像对比度准则的最优成像时间段选择方法。该方法根据海舰船回波的实际数据,估计各个回波的多普勒中心频率,并根据多普勒中心曲线选取舰船目标的线性成像段。然后,通过采用图像对比度准则,对该线性段进行处理。相比已有的方法,本文的成像效果更好。该方法易于实现且运算量较低,适用于实时应用。仿真数据的处理结果验证了本文所提方法的有效性。

New ISAR imaging interval selection method for ship targets on sea based on imaging contrast

To solve the problem of imaging ambiguity when there is random sway of ship target in inverse synthetic aperture radar (ISAR) application, a method for selecting optimal imaging time based on estimation of the Doppler centroid frequencies (DCF) and image contrast is proposed. This method calculates Doppler center from real echoes of ship target, then chooses optimal imaging time according to the change of Doppler center. After that, a definition of image contrast is given to help dealing with selecting optimal imaging time. In comparison with existing methods, the proposed one can select better period for ISAR imaging which leads to an imaging result with higher quality. The method is easy to implement and computational complexity is lower, which is suitable for real time applications. The effectiveness of the proposed method is verified by the simulation data processing result.