基于多频段拼接的高分辨率太赫兹成像技术  

High-resolution terahertz imaging technology based on multi-band stitching

作　　者：周子悦 年夫顺 孙超 张婷 董继刚 Zhou Ziyue;Nian Fushun;Sun Chao;Zhang Ting;Dong Jigang(School of Instrument and Electronics,North University of China,Taiyuan 030051,China;Ceyear Technology Co.,Ltd.,Qingdao 266400,China;Shandong Province Electronic Measuring Instrument Technology Innovation Centre,Qingdao 266400,China;Qingdao Advanced Test Technology Laboratory,Qingdao 266400,China)

机构地区：[1]中北大学仪器与电子学院,太原030051 [2]中电科思仪科技股份有限公司,青岛266400 [3]山东省电子测量仪器技术创新中心,青岛266400 [4]青岛市先进测试技术实验室,青岛266400

出　　处：《仪器仪表学报》2024年第5期138-146,共9页Chinese Journal of Scientific Instrument

摘　　要：为解决带宽限制导致的太赫兹调频连续波成像纵向分辨率低的问题,提出一种适用于线性调频体制的多频段拼接的方法。该方法基于参考信号的非线性补偿算法,改进传统宽带时域合成算法,在非线性校正的同时实现各频段信号频率和相位上的连续性,无需再进行频移和相位补偿。搭建0.11~0.75 THz 5个频段线性调频成像系统进行实验验证,结果表明,该方法显著提高太赫兹成像纵向分辨率,同时提高材料介电常数测试精度,未来可应用于材料测试领域。此外,设计了表面台阶型样品和多层胶粘的内部缺陷样品进行成像,证明融合信号的图像包含更多的细节,样品的每一层分离得更为明显,高度差仅0.2 mm也能清晰地分辨,能够满足高精度无损检测的需求。To address the issue of low-range resolution caused by bandwidth limitation in terahertz imaging,this article proposes a multi-band stitching method for the linear frequency-modulated continuous wave system.The method enhances the conventional time-domain synthetic bandwidth algorithm by incorporating a non-linear compensation algorithm based on a reference signal.This method ensures frequency and phase continuity for each frequency band while rectifying non-linear effects,thereby eliminating the need for further frequency shift and phase compensation.Experimental results using a linear FM imaging system with five frequency bands ranging from 0.11 to 0.75 THz show that the proposed method can significantly improve the longitudinal resolution of teraherz imaging and improve the accuracy of material dielectric constant measurement,and can be applied to the field of materials testing in the future.In addition,two surface step samples and an internal defect sample with an adhesive multilayer are designed for imaging.The imaging results reveal that the fused signals contain more detailed information compared to individual bands,enabling clearer separation of each layer within the samples.Additionally,steps with a height difference of only 0.2 mm can be distinctly distinguished,which can meet the demands of high-precision non-destructive testing.

关 键 词：太赫兹成像 线性调频连续波 多频段拼接 无损检测 材料介电常数 

分 类 号：TN957[电子电信—信号与信息处理] TH89[电子电信—信息与通信工程]