距離彎曲情形的超分辨成像及目標特征參量提取
SUPER-RESOLUTION IMAGING AND TARGET FEATURE EXTRACTION IN THE PRESENCE OF WAVEFRONT CURVATURE EFFECTS
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摘要: PFA算法的性能受到距離彎曲引起的成像誤差的影響,傳統(tǒng)的處理方法是限制場景的尺寸。本文從超分辨處理的角度出發(fā),對距離彎曲引起的空變的二次相位誤差(QPEs)采取精確估計和補償?shù)姆椒ㄟM行預處理,然后得到超分辨圖像及目標特征參量。相位誤差的粗估計采用離散多項式相位變換(DPT)方法,而誤差精估計則基于RELAX類算法。仿真和實測數(shù)據(jù)證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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