The real-time capability becomes more and more important for the millimeter-wave imaging systems in variety of applications. To achieve this purpose, the imaging scheme with multiple-input–multiple-output (MIMO) is one of the potential ways, while still limited by the high computational complexity of the conventional MIMO image reconstruction algorithm, which is commonly based on the back-projection theorem. In this letter, an efficient phase shift migration (PSM) image reconstruction algorithm was proposed to improve the computation efficiency for MIMO systems 2-D imaging. By decomposing and approximating the PSM operator reasonably, only complex multiplication and Fourier transform (FT) operations are employed which can be easily carried out to reduce computation cost. An MIMO side-looking prototype system was designed for proof experiments in the 100-GHz band. Although the proposed algorithm introduces a negligible phase error, the experimental results show that the error can be ignored and the algorithm can achieve high-precision real-time imaging.

中文翻译：

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毫米波频带中MIMO 2-D成像的有效相移迁移

对于各种应用中的毫米波成像系统而言，实时功能变得越来越重要。为了达到这个目的，采用多输入多输出（MIMO）的成像方案是一种可能的方式，同时仍然受到传统MIMO图像重建算法的高计算复杂度的限制，该算法通常基于反向投影定理。在这封信中，提出了一种有效的相移迁移（PSM）图像重建算法，以提高MIMO系统二维成像的计算效率。通过合理地分解和逼近PSM运算符，仅采用复杂的乘法和傅立叶变换（FT）运算即可轻松实现，从而降低了计算成本。MIMO侧视原型系统设计用于100 GHz频段的验证实验。尽管该算法引入的相位误差可以忽略不计，但是实验结果表明该误差可以忽略，并且可以实现高精度的实时成像。