基于长脉冲热激励的红外序列图像处理方法  

Processing Method of Infrared Sequence Images Based on Long Pulse Thermal Excitation

作　　者：魏延杰 肖瑶 Wei Yanjie;Xiao Yao(Department of Engineering Mechanics,Shijiazhuang Tiedao University,Shijiazhuang 050043,Hebei,China;State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures,Shijiazhuang Tiedao University,Shijiazhuang 050043,Hebei,China)

机构地区：[1]石家庄铁道大学工程力学系,河北石家庄050043 [2]石家庄铁道大学省部共建交通工程结构力学行为与系统安全国家重点实验室,河北石家庄050043

出　　处：《光学学报》2024年第8期63-73,共11页Acta Optica Sinica

基　　金：国家自然科学基金(12072184,12002222)。

摘　　要：针对长脉冲热波激励后采集到的红外原始热图中缺陷对比度低、缺陷边缘模糊等问题,本文提出了一种基于傅里叶变换、频域相位积分和保边滤波的红外序列图像处理方法,该算法首先对冷却时间段内采集到的红外原始热图进行消背景处理,再利用傅里叶变换将试样表面的红外辐射信息转化为相位信息,频域相位积分处理可以将不同频率下缺陷的相位信息整合至一幅相位积分图中,最后通过保边滤波器及自适应伽马变换对积分图像进行增强和量化。该算法克服了传统方法需要人工从多张频率或成分图中甄别出最优检测结果的缺点,并且可以消除加热不均匀的影响,改善缺陷的可视化。试验结果从定性和定量两个角度验证评估了该算法的有效性,并讨论了采集参数的影响。Objective Defects such as debonding,bulges,pores,pits,delaminations,and inclusions in composites are common during manufacture and service.They not only reduce strength and stiffness but also fail structures.Reliable nondestructive testing methods are required to assess the quality of composite materials.Long pulse thermography(LPT)is a full-field,non-contact,and non-destructive testing method based on image visualization that provides an efficient way to assess the defect quality.However,the defect visibility of LPT can be compromised by various factors such as experimental conditions,heat intensity,inherent material properties,and noise.The LPT effectiveness is constrained by fuzzy edges and low-contrast defects.Consequently,enhancing defect visibility via signal processing methods is crucial for inspecting defects in composite materials using LPT.Thus,we propose an infrared image sequence processing method that utilizes Fourier transform,phase integration,and edge-preserving filters to enhance the quality of LPT detection results for composite materials.Meanwhile,a few latent variables that better reflect the defect information inside the specimen are proposed by transforming the temperature information of the surface during the cooling period.These variables can eliminate the influence of uneven heating and improve defect visualization.This method enables clear delineation of defect edges and accurate measurement of defect sizes.Our approach and findings are expected to contribute to qualitative and quantitative measurements in the non-destructive testing of composite structures.Methods We propose a novel infrared image sequence processing algorithm to enhance the defect visibility of LPT.This approach comprises four steps of background uniformity processing,phase extraction,frequency domain integration,and image quantization.Initially,thermal data is acquired after a square pulse heating period and subsequently pre-processed to eliminate the inhomogeneity of the initial temperature distribution.Subsequently,

关 键 词：长脉冲热像法 傅里叶变换 相位增强 复合材料 

分 类 号：O436[机械工程—光学工程]