基于会聚球面波数字聚焦的安检毫米波成像新方法研究

Security & inspection techniques for counter-terrorism are in great demand especially for important application scenarios such as airport, frontier port, and urban rail transit. Millimeter-wave (MMW)/THz imaging techniques have great application potentials in security inspection of body concealed hazard items, and the initial applications have already been promoted in several foreign countries. However, there are still some restrictions limiting the application of this technology. Firstly, requirements of short-range and long-range imaging cannot simultaneously be satisfied. Secondly, advantages of the active and the passive imaging systems cannot be achieved at the same time. Finally, the contradiction between real-time imaging and spatial resolution needs to be carefully dealt with. Therefore, it has significant scientific meanings to explore and develop a novel imaging method and relevant techniques to satisfy the demands on the simultaneous short-range and long-range imaging capability, the compound active and passive imaging power, and the real-time imaging ability with extended depth of field and high spatial resolution. . Targeting at this issue, the imaging mechanism with extended depth of field and digital focusing abilities based on converging spherical waves will firstly be studied. The compound active and passive imaging methods to improve the image quality will then be explored to process and merge the active imaging data with multi-polarization information acquired by the heterogeneous MMW imaging modules and antenna arrays with the passive ones detected by the MMW radiometry. Taking advantage of the quasi-optical rapid scanning, a digital-focusing MMW imaging method with extended depth of field based on converging spherical waves will be proposed. An experimental prototype of the imaging system will be manufactured and tested in typical application scenarios to validate the proposed imaging mechanisms and methods. The research achievements will lay both theoretical and practical foundations for developing novel MMW/THz imaging systems for human body security inspection applications.

机场口岸、轨道交通等重要场所对安检反恐技术的需求非常迫切，毫米波/太赫兹成像在人体隐匿危险物品安全检测领域应用潜力巨大，在国外已初步应用，但仍存在一定局限，迫切需要解决近距离和站开式成像需求无法兼顾、主动式和被动式成像优点无法兼顾、成像速度与分辨率无法兼顾这三大矛盾。探索其中的关键科学问题和技术难点，发展新方法新体制，实现同时满足近距离及站开式成像要求的主被动复合大景深实时高分辨率成像方法具有重要的科学意义。本项目将开展基于会聚球面波数字聚焦的大景深成像机理研究、采用主被动混合成像方法，将异构多频段毫米波成像模块及天线阵列所获取的主动多极化全息成像数据和被动毫米波辐射测量数据进行信息融合，结合准光学快速扫描，提出一种基于会聚球面波数字聚焦的安检毫米波成像新方法，并建立原理性实验验证系统，在典型应用环境中验证研究成果。项目实施将为发展新型毫米波/太赫兹人体安检系统奠定理论和实践基础。

机场口岸、轨道交通等重要场所对于安检反恐技术的需求日益迫切，目前毫米波/太赫兹成像探测技术在人体隐匿危险物品安全检测领域的研究已经取得了一定的成果，但仍存在一定局限，如何兼顾近距离和站开式成像、兼顾主动式和被动式成像的优点、兼顾成像速度和成像分辨率，探索毫米波成像新方法，是毫米波成像技术应用于安检领域迫切需要解决的问题。本项目面向安检毫米波成像应用，对实现大景深、高空间分辨率、主被动融合的高帧频成像新方法进行了深入研究，首次提出了基于贝塞尔波束的大景深毫米波介质透镜、长焦深和高分辨率成像聚焦超表面的实现机理和方法，构建了被动焦距捷变成像模型，研究了会聚球面波数字重聚焦方法，实现了大景深高空间分辨率成像；研究了基于极化和散射信息融合的主被动成像方法，提出了基于极化散射矩阵的目标参数估计与特征分类方法。提出了基于泽尼克多项式自由曲面的多波束聚焦天线和快速扫描方法，解决了焦平面阵列馈源天线偏焦时产生的焦斑畸变，提高了成像分辨率的同时实现快速成像。为实现上述方法构建了异构多频段毫米波成像模块及天线阵列，并研制了原理性实验验证系统，进行了系统性能测试和人体衣物下隐匿危险品探测实验，并基于该平台进行多极化主被动融合成像和隐匿危险品识别方法验证。依托本项目，培养了博士研究生16名，硕士研究生45名，在高水平期刊和会议上发表学术论文54篇，出版专著2本，申请和授权国家发明专利15项，获黑龙江省科学技术奖三等奖，举办了2022中国微波周、中乌科技论坛等国际国内学术会议，项目负责人邱景辉教授于2022年获乌克兰科技进步个人最高奖。本项目成果已在国内多家单位试用，未来具备较好的推广应用前景。