CAJ | 학술논문

SAR图像的自聚焦处理依赖图像域与距离压缩相位历程域之间的傅里叶变换对(Fourier Transform Pairs, FTP)关系。与频域算法不同，时域算法下的这种FTP关系不仅复杂，且难以获取。为了兼顾图像快速重建和自聚焦处理，该文首先对快速分解后向投影(Fast Factorized Back-Projection, FFBP)算法进行必要的改进和适当的优化处理，提出了IFFBP(Improved FFBP, IFFBP)算法，为自聚焦算法的使用奠定了基础。其次，针对数据处理的实际需求，该文提出了一种结合中等精度惯导粗补偿、嵌套相位梯度自聚焦(Phase Gradient Autofocus, PGA)精补偿的IFFBP算法处理流程。最后，通过仿真实验和实测数据处理验证该文方法的有效性。
SAR도상적자취초처리의뢰도상역여거리압축상위역정역지간적부리협변환대(Fourier Transform Pairs, FTP)관계。여빈역산법불동，시역산법하적저충FTP관계불부복잡，차난이획취。위료겸고도상쾌속중건화자취초처리，해문수선대쾌속분해후향투영(Fast Factorized Back-Projection, FFBP)산법진행필요적개진화괄당적우화처리，제출료IFFBP(Improved FFBP, IFFBP)산법，위자취초산법적사용전정료기출。기차，침대수거처리적실제수구，해문제출료일충결합중등정도관도조보상、감투상위제도자취초(Phase Gradient Autofocus, PGA)정보상적IFFBP산법처리류정。최후，통과방진실험화실측수거처리험증해문방법적유효성。
The Fourier Transform Pairs (FTP) between the image domain and its corresponding range-compressed phase history domain is critical for autofocus. Different from the frequency-domain algorithms, this requirement of FTP is both complicated and difficult to be met in the time-domain algorithms. For a swift and effective reconstruction and autofocus processing of imagery created by the time-domain algorithm, the necessary improvement and optimization in the Fast Factorized Back-Projection (FFBP) is performed, presenting an Improved FFBP (IFFBP) algorithm further. Through the pseudo-polar coordinate system, the IFFBP is able to pave the way for autofocus application. Also, in view of the practical requirements for data processing, the IFFBP uses a moderate-accuracy Inertial Measurement Unit (IMU) to achieve a coarse compensation,and combines with the Phase Gradient Autofocus (PGA) to make a fine compensation. Finally, the simulation results and the collected data sets verify and validate the proposed approach.