基于经验小波系数模态分解的太赫兹成像纵向分辨增强  

Longitudinal resolution enhancement of terahertz imaging based on empirical wavelet coefficient mode decomposition

作　　者：李志龙 左剑[1] 赵源萌[1] 韩钟德 许志浩 赵云璋 杨朝 胡伟东[2] 张存林[1] LI Zhi-Long;ZUO Jian;ZHAO Yuan-Meng;HAN Zhong-De;XU Zhi-Hao;ZHAO Yun-Zhang;YANG Chao;HU Wei-Dong;ZHANG Cun-Lin(Beijing Key Laboratory for Terahertz Spectroscopy and Imaging,MOE Key Laboratory of Terahertz Optoelectronics,Department of Physics,Capital Normal University,Beijing 100048,China;Beijing Key Laboratory of Millimeter Wave and Terahertz Technology,School of Information and Electronics,Beijing Institute of Technology,Beijing 100081,China;Kuang-Chi Silver Star Base Technology Room,Shenzhen Kuang-Chi Advanced Technology Co.,Ltd,Shenzhen 518000,China)

机构地区：[1]首都师范大学物理系北京市太赫兹波谱与成像重点实验室太赫兹光电子学教育部重点实验室,北京100048 [2]北京理工大学信息与电子学院毫米波太赫兹技术北京市重点实验室,北京100081 [3]深圳光启尖端技术有限责任公司光启银星基地技术室,广东深圳518000

出　　处：《红外与毫米波学报》2022年第4期710-720,共11页Journal of Infrared and Millimeter Waves

基　　金：成像技术高精尖创新中心科技创新服务能力建设基金(008/19530012003);首都师范大学分类发展--学位点建设与研究生教育立项及研究生高水平学术创新-物理系-专业学位实践基地项目(008-2155089)。

摘　　要：为了提高太赫兹成像探测的纵向分辨率,提出了一种基于连续小波的经验模态分解的纵向分辨率增强新方法。首先先对样品的频域信号进行连续小波变换处理,获得其相对应的连续小波变换系数;然后对获得的连续小波系数进行经验模态分解,将其自适应地分解为一系列的本征模式函数和一个残差信号,并提取其中第一阶本征模式函数为成像参数进行三维重构,获得最终的三维本征模函数图像,以此来提高太赫兹检测图像的纵向分辨率。为验证方法的有效性,采用150~220 GHz高频太赫兹调频雷达成像系统分别对两种含内部脱胶缺陷的夹层结构复合材料进行成像检测并利用提出的方法进行处理,得到了纵向分辨率被有效增强,清晰度被有效提高的检测结果图像,这为未来的太赫兹计算机断层扫描成像和太赫兹无损检测应用研究提供了新的思路。In order to improve the longitudinal resolution of terahertz imaging detection,a novel longitudinal resolution enhancement method based on empirical mode decomposition of continuous wavelet was proposed.Firstly,the frequency domain signals of the sample are processed by continuous wavelet transform to obtain the corresponding continuous wavelet transforms coefficients.Then,the obtained continuous wavelet coefficients are decomposed by empirical mode decomposition,which is adaptive decomposed into a series of intrinsic mode functions and a residual signal.And the first-order intrinsic mode functions are extracted as the imaging parameter for 3D reconstruction to obtain the final 3D intrinsic mode function image,so as improving the longitudinal resolution of terahertz detection image.In order to verify the effectiveness of the method,the 150~220 GHz high frequency terahertz frequency modulated radar imaging system was used to detect two kinds of sandwich structure composite material with internal adhesive debonding defects,and the proposed method was used to process them.The detection results images of the longitudinal resolution effectively enhanced and the sharpness effectively improved was obtained,which provides a new idea of future terahertz computer tomography imaging and terahertz non-destructive testing research.

关 键 词：太赫兹成像 连续小波变换 经验模态分解 纵向分辨率增强 

分 类 号：O43[机械工程—光学工程]