基于两维空变滤波的PFA波前弯曲误差补偿

Polar format algorithm wavefront curvature error compensation using 2Dspace-variant post-filtering

极坐标格式算法(PFA)因受波前弯曲误差的影响,其有效成像场景范围受到一定的限制。采用图像域的空变滤波(SVPF)处理可以有效补偿波前弯曲误差,但为了简化分析,已有SVPF方法在补偿过程中都采取了一定的近似,在对大场景进行高分辨率成像时仍然不能满足聚焦精度要求。对PFA的极坐标格式转换给出了一种新的解析解释,利用该解释推导得到了精确的波前弯曲误差表达式;基于该波前弯曲误差模型,提出了一种基于两维SVPF处理的波前弯曲误差补偿方法。最后通过仿真数据处理验证了该算法的有效性。

The space-variant defocus effect introduced by wavefront curvature error in polar format algorithm（PFA）imagery limits its maximal focused scene size.Space-variant post-filtering（SVPF）is an efficient approach to compensate for this error.However,to simplify the analysis,all the existing SVPF methods take some approximation on the wavefront curvature error.They can still not meet the required precision when imaging large area with very high resolution.In this paper,we provide a new analytical interpretation of polar format algorithm and develop the accurate wavefront curvature expression in2 Dspatial frequency domain.Base on this accurate expression,a 2DSVPF is proposed to accurately correct the wavefront curvature error.Finally,simulation experiment validates the theoretical analysis.