距离弯曲情形的超分辨成像及目标特征参量提取
SUPER-RESOLUTION IMAGING AND TARGET FEATURE EXTRACTION IN THE PRESENCE OF WAVEFRONT CURVATURE EFFECTS
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摘要: PFA算法的性能受到距离弯曲引起的成像误差的影响,传统的处理方法是限制场景的尺寸。本文从超分辨处理的角度出发,对距离弯曲引起的空变的二次相位误差(QPEs)采取精确估计和补偿的方法进行预处理,然后得到超分辨图像及目标特征参量。相位误差的粗估计采用离散多项式相位变换(DPT)方法,而误差精估计则基于RELAX类算法。仿真和实测数据证明了本文方法的有效性。Abstract: Wavefront curvature defocus effects can occur when Polar Formatting Algorithin(PFA)is used to reconstruct the SAR image. The traditional approach to this situation is simply to limit the size of the scene reconstructed. From the aspect of super-resolution, it is demonstrated in this paper that by accurate estimation and post compensation of the space-variant Quadratic Phase Errors(QPEs), super-resolution image and target features can still be obtained in the presence of wavefront curvature effects. The estimate. of QPEs is roughly obtained by use of the Discrete Polynomial-Phase TranSfornl(DPT), then it is refined by a RELAX-based parametric estimation rnet.hod. Experimental results show the effectiveness of the, proposed method.
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