基于投影-切片定理的转台成像算法

Rotating target imaging algorithm based on the projection-slice theorem

  • 摘要: 在ISAR成像中,目标经过运动补偿等处理后均可看作转台目标,因此分析转台目标成像的原理和性能具有重要的意义。本文首先根据运动相对性原理,建立了转台目标回波信号模型。接着在计算机层析成像技术框架下详细推导了基于投影-切片定理的转台成像公式以及三种实现算法:二重积分法、极坐标格式算法和卷积逆投影算法,指出远场近似是投影-切片定理得以运用于转台成像的关键。最后通过MATLAB仿真实现了转台目标散射中心位置的二维重构,并从适用性和成像效果两方面,对三种实现算法进行了分析比较,所得结果可为实际应用中不同成像要求下成像算法的选择提供一定的理论依据。

     

    Abstract: In inverse synthetic aperture radar (ISAR) imaging, moving targets can be seen as turntable targets after motion compensation, and therefore the analysis of rotating-target imaging theory and its performance is of great significance. In the beginning, the echo model of turntable targets is established according to the theory of motion relativity. With the help of computerized tomography imaging technique, the turntable targets imaging formula based on the projection-slice theorem is deduced in detail, and then three specific algorithms are derived, of which are the double integration algorithm, the polar format algorithm (PFA) and the convolution back projection algorithm (CBPA), respectively. Meanwhile it is indicated that far field approximation is the key of projection-slice theorem for being applied to the turntable targets imaging. In the end, the two dimensional reconstruction of target scattering centers is realized by the MATLAB simulation, and the three algorithms are analyzed and compared from the aspects of applicability and imaging performance. The result obtained is able to provide the rationale for algorithm selection in various imaging requirements in practice.

     

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