基于FPGA的SAR图像Lee滤波器算法实现

The Implementation of Lee Filtering Algorithm for SAR Image Based on FPGA

在以SAR图像为基础的导弹末制导系统中,对图像匹配的速度要求很高,如果用软件实现去除图像相干斑的Lee滤波算法,处理时间相对较长,失去了其实际应用的价值。为解决这一问题,可以利用FPGA来实现Lee滤波算法,针对算法中运算消耗时间较多的开方运算、指数运算,建立高效的算法模型,本文实现了开方运算仅需要2个迭代周期、指数运算仅需要3个时钟周期。最终,利用FPGA实现的Lee滤波器算法运算时间是软件运算时间的1/4,为其应用在导弹末制导系统中奠定了基础。

In the system of missile terminal guidance based on SAR image,the high image matching speed is required.It is not applicable in the application of missile in which Lee filtering algorithm for filtering speckle on SAR image is implemented by using software.Due to the problem of long time processing,the Lee filtering algorithm is implemented by using FPGA.The time consuming problem of the calculation of extracting root and exponential by using proposed algorithms is resolved.Eventually the results show that the calculation of extracting root consumes two iterative cycles and the calculation of exponential consumes three clock periods.The consuming time of Lee filtering algorithm by applying FPGA is quarter while using software.