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在近程大斜视成像中,当采用距离徙动算法进行处理时,信号谱在有限谱域范围内发生偏移,引起多次翻折造成混叠,使得通常处理方式不再适用。为此,提出一种解混叠方法恢复实际信号谱,通过斜视角或目标中心偏移量可计算出信号谱的翻折次数,依据翻折次数可将信号谱恢复至实际谱域位置,进而依照距离徙动算法流程进行处理即可实现大斜视成像。该方法基于信号谱进行,未对距离方程进行近似处理,因此不仅适用于远场,同时可以解决近场大斜视成像问题。计算机仿真和实际实验测量结果显示,采用所提出的方法处理后可对成像范围内的目标实现精确聚焦。本算法适用近程条件下阵列或合成孔径的大斜视成像问题,可对60o~70o的斜视角情况实现精确聚焦。同时,本算法的流程清晰,易于实际编程处理实现。
In short-range strabismus imaging, when the distance migration algorithm is used for processing, the signal spectrum shifts within the limited spectral range, resulting in aliasing caused by multiple folds, making the normal processing method no longer suitable. To solve this problem, an anti-aliasing method is proposed to recover the actual signal spectrum, and the signal spectrum can be calculated by calculating the angle of incidence or the target center offset. Based on the number of times of folding, the signal spectrum can be restored to the actual spectrum position. Large strabismus imaging can be achieved by processing according to the distance migration algorithm flow. The method is based on the signal spectrum and does not approximate the distance equation, so it is not only applicable to the far field, but also can solve the problem of near-field strabismus imaging. Computer simulation and actual experimental measurements show that the proposed method can achieve precise focusing on the target in the imaging range. This algorithm is suitable for large strabismus imaging problems of array or synthetic aperture under short-range conditions, and can accurately focus on the 60 ° ~ 70 ° squint angle. At the same time, the flow of the algorithm is clear, easy to actual programming and processing.