Infrared thermography in metabolic diseases

The prevalence of metabolic diseases,some diseases that are seriously harmful for human health and affect the quality of life,is increasing year by year.Early detection and intervention is the common strategy to deal with them.Infrared thermography(IRT)is a special medical imaging technology which can capture the changes of skin temperature associated with metabolic disorders.It might be a new method for early detection of metabolic diseases.The purpose of this review is to summarize advances of the use of IRT in evaluating single metabolic disorder such as obesity,hyperglycemia and hypertension,complex metabolic disorders such as metabolic syndrome and target organ damage such as coronary artery atherosclerosis and diabetic foot.The characteristic of thermograms of metabolic disease patients,the changes of thermal maps during the development of the disease,and the lacks in current studies are also discussed in the article.

Anisotropy of Fatigue Behavior and Tensile Behavior of 5A06 Aluminum Alloy Based on Infrared Thermography

The fatigue behavior during high cycle fatigue testing and the tensile behavior of 5A06 aluminum alloy considering the anisotropy were studied.Two types of specimens including longitudinal specimen（parallel to the rolling direction） and transverse specimen（perpendicular to the rolling direction） were prepared.Infrared thermography was employed to monitor the temperature evolution during the fatigue and tensile tests.The temperature evolution curves in the two directions were contrastively analyzed.It is found that the temperature evolution during fatigue process possesses four stages：initial temperature rise stage,slow temperature decline stage,rapid temperature rise stage,and finial temperature decline stage.The heat generating mechanisms of the four stages are discussed.Obvious differences can be found between the longitudinal specimen and transverse specimen in fatigue strength and fatigue life.The fatigue strength and fatigue life of longitudinal specimen are higher than those of transverse specimen.During the tensile and fatigue testing process,the fracture temperature in the transverse direction are higher than that in the longitudinal direction.The fatigue strength prediction by means of infrared thermography has a good consistency with that by the traditional method.

Bridge Girder Crack Assessment Using Faster RCNN Inception V2 and Infrared Thermography

Manual inspections of infrastructures such as highway bridge, pavement, dam, and multistoried garage ceiling are time consuming, sometimes can be life threatening, and costly. An automated computerized system can reduce time, faulty inspection, and cost of inspection. In this study, we developed a computer model using deep learning Convolution Neural Network (CNN), which can be used to automatically detect the crack and non-crack type structure. The goal of this research is to allow application of state-of-the-art deep neural network and Unmanned Aerial Vehicle (UAV) technologies for highway bridge girder inspection. As a pilot study of implementing deep learning in Bridge Girder, we study the recognition, length, and location of crack in the structure of the UTC campus old garage concrete ceiling slab. A total of 2086 images of crack and non-crack were taken from UTC Old Library parking garage ceiling using handheld mobile phone and drone. After training the model shows 98% accuracy with crack and non-crack types of structures.

Quantification by Signal to Noise Ratio of Active Infrared Thermography Data Processing Techniques

In this paper, the use of a signal to noise ratio (SNR) is proposed for the quantification of the goodness of some selected processing techniques of thermographic images, such as differentiated absolute contrast, skewness and kurtosis based algorithms, pulsed phase transform, principal component analysis and thermographic signal reconstruction. A new hybrid technique is also applied (PhAC—Phase absolute contrast), it combines three different processing techniques: phase absolute contrast, pulsed phase thermography and thermographic signal reconstruction. The quality of the results is established on the basis of the values of the parameter SNR, assessed for the present defects in the analyzed specimen, which enabled to quantify and compare their identification and the quality of the results of the employed technique.

Counting Method of Mangrove Pests Based on Infrared Thermography

In the field of plant protection,certain methods for assessing the current pest situation and implementing appropriate protection countermeasures can effectively protect plants while saving manpower and material resources.However,current pest monitoring methods are primarily based on the stage of"seeing,hand checking,disc shooting and net catching",and the level of automation is low.Manual methods are time-consuming,prone to error,and difficult to review.We designed a method based on infrared thermography principle for counting Ricania guttata(Walker),a pest which is harmful to mangrove plants.This method,which is based on thermal infrared images and binarized image segmentation,realizes image processing of surface temperature,effectively distinguishes pests and sticky board,automatically counts the number of pests,and expands the data source based on image processing.Furthermore,this method contributes to the solution of the problem that counting error of insect close to the color of sticky board is greater in image recognition of visible light,when the pest color is close to the stick board.It can facilitate manual investigation of mangrove pests,simply and efficiently count the number of pests on the stick board,and provide data and technical support for pest condition analysis and control.

Study on divertor heat flux under n=3 and n=4 resonant magnetic perturbations using infrared thermography diagnostic in EAST

Resonant magnetic perturbations(RMPs)with high toroidal mode number n are considered for controlling edge-localized modes(ELMs)and divertor heat flux in future ITER H-mode operations.In this paper,characteristics of divertor heat flux under high-nRMPs(n=3 and 4)in H-mode plasma are investigated using newly upgraded infrared thermography diagnostic in EAST.Additional splitting strike point(SSP)accompanying with ELM suppression is observed under both RMPs with n=3 and n=4,the SSP in heat flux profile agrees qualitatively with the modeled magnetic footprint.Although RMPs suppress ELMs,they increase the stationary heat flux during ELM suppression.The dependence of heat flux on q_(95)during ELM suppression is preliminarily investigated,and further splitting in the original strike point is observed at q 495=during ELM suppression.In terms of ELM pulses,the presence of RMPs shows little influence on transient heat flux distribution.

Comparison between Microwave Infrared Thermography and CO₂Laser Infrared Thermography in Defect Detection in Applications with CFRP

This paper presents two infrared thermography methods with CO2 Laser excitation and microwave excitation applied to defect detection in CFRP. The tests were conducted with two specimens, one with defect, and another one without defect. On two concrete plates 40 cm× 40 cm× 4.5 cmwere reinforced by CFRP;the defects were made by the absence of adhesive on an area10 cm× 10 cm. The specimens were heated by microwave, generated by a commercial magnetron of 2.45 GHz and guided by a pyramidal horn antenna, with a power of 360 W within 150 s. Another series of the tests was conducted with CO2 Laser, wavelength 10.6 μm, by heating the samples with a power of 300 W within 40 s. An infrared camera sensitive to medium waves in range of 3 - 5 μm, with a detector of 320 × 256 matrix detector in InSb (Indium Antimonide), was used to record the thermograms. As a result, the CO2 Laser excitation is better for the delamination detection in CFRP. This study opens interesting perspectives for inspecting other types of defects in materials sciences;the microwave excitation is suitable for the deep defects in the materials whereas the CO2 Laser excitation is better for the defects near the surface of the materials.

Laser Heating and Infrared Thermography of Building Materials

In this work, a 532 nm diode CW laser is used to heat samples used as building materials at a 1 meter standoff distance while using an FLIR (Forward-Looking Infrared) thermal camera to monitor and record the heating and then cooling of each sample after lasers are switched off. The data is then analyzed using FLIR proprietary software. Since the absorption spectra of materials are unique, using multiple lasers of different wavelengths to simultaneously shine onto the sample at different locations would give enough thermal data to successfully characterize the samples within a reasonable amount of time. The results are very promising for applications involving non-destructive detection and classification of materials.

Pulse modulated microwave and infrared thermography for superficial hyperthermia

A 3D temperature field distribution of biological tissue for superficial hyperthermia using a pulse modulated microwave (PMMW) was presented.A 3D sliced homogeneous phantom was radiated by the PMMW and an infrared thermal imager was applied to image temperature distribution throughout the phantom.The period of the PMMW is 3 s and the output power is 35 W.The temperature rises by at least 3 °C in the phantom when the duty cycle varies from 1/3,1/2,2/3 to 1 (denoted by scenarios 1?4).Both the accumulative temperature?volume histogram and the relative depth?area ratio histogram show that the maximum temperature rise (MTR) is 6.6 and 8 °C in scenarios 2 and 3,and they are superior to scenarios 1 and 4.Furthermore,the PMMW can control temperature field distribution of biological tissue.It provides both preliminary basis for thermal volume control and new technology for temperature control and monitor in superficial hyperthermia.

NDI of Rail Squats and Estimating Defect Size and Location Using Lock-In Thermography

Rail squats are a form of near surface rolling contact fatigue damage found in rail heads. Currently, the most popular method to detect the rail squats is utilizing ultrasonic techniques to determine their presence and measure their depths. This technique needs to be direct contact between the probe and the rail head, with a coupling fluid in at the interface. Other weaknesses of these ultrasonic techniques include false detections as well as missed detections. Infrared thermography is a relatively new non-destructive inspection technique used for a wide range of applications but is not used for rail squat detection. Lock-in thermography is a non-destructive inspection technique that can be used for the detection of near surface defects. It utilizes an infrared camera to detect the thermal waves and then produces a thermal image, which displays the local thermal wave variation in phase or amplitude. In inhomogeneous materials, the amplitude and phase of the thermal wave carries information related to both the local thermal properties and the nature of the structure being inspected. This comparison is then used to determine the phase angle difference (Δf) between the input and the thermal response of the object. The aim of this paper is to determine whether lock-in thermography can be used to firstly locate squats in rails, and secondly measure their depths. It has demonstrated the feasibility for using such a technique in generating thermal responses that could be adequately utilized for the purpose of defect characterization.

Remote sensing of bark beetle damage in Norway spruce individual tree canopies using thermal infrared and airborne laser scanning data fusion

Background:Increasing threat to Central Europe’s forests from the growing population of the European spruce bark beetle Ips typographus (L.) calls for developing highly effective methods of detection of the infestation spots. The main goal of this study was to establish an automatic workflow for detection of dead trees and trees in poor condition of Picea abies using Middle Wave Infrared spectral range obtained from the aircraft.Methods:The studies were conducted in Wigry National Park (Poland) in 2020. A fusion of aircraft thermal data and laser scanning was used. Synchronous with thermal data acquisition ground reference data were obtained for P. abies in different health conditions. Determination of the range of canopy temperatures characteristic of the three condition states (‘healthy’,‘poor condition’,‘dead’) was performed using K-mean clustering. The accuracy of the method was evaluated on two validation sets:(1) individual tree canopies determined by photointerpretation, and (2) automatic segmentation of laser scanning data.Results:The results showed that the average temperature of ‘healthy’trees was 27.70℃, trees in ‘poor condition’28.57℃, and ‘dead’trees 30.17℃. High temperature differences between ‘healthy’and ‘dead’P. abies made it possible to distinguish these two condition classes with high accuracy. Lower accuracies were obtained for the class of ‘poor condition’, which was found to be confusing with both ‘healthy’and ‘dead’trees. According to results from the first validation set, a high overall accuracy of 0.60 was obtained. For the second validation set, the overall accuracy was reduced by 11%.Conclusions:This study indicates that canopy temperature recorded from the airborne level is a variable that differentiates ‘healthy’spruces from those in ‘poor condition’and the ‘dead’trees. The results confirmed that thermal and airborne laser scanning data fusion allows for creating a quick and simple workflow, which can successfully separate individual tree canopies and identify P. abies attacked by I. typographus. Further research is needed to identify trees in the early stages of invasion.

升力体缝隙模型红外测热试验及分析

针对升力体缝隙模型在中国空气动力研究与发展中心的Φ0.3 m高超声速低密度风洞中开展了红外测热试验,试验马赫数12、总温668 K、总压4.731 MPa、攻角0°和35°,获取了模型的红外热图结果,并开展了相应的数值仿真分析。在此基础上,研究了选取不同帧次的红外热图进行数据处理对热流密度结果的影响,分析了缝隙干扰引起的热流密度增量。结果表明:投放后模型抖动对数据处理存在明显影响,建议在数据处理中采用模型投放稳定后(约1.2 s)的红外热图结果;“T”字型缝干扰区的热流密度增量需要引起重视,攻角35°情况下的峰值热流密度能达到无缝隙时热流密度的8倍以上;红外测热试验数据与CFD数据吻合较好,两者仅在很小的峰值干扰区域存在差异。下一步需要在CFD建模倒角处理、红外方案优化等方面开展工作。

太阳能激励下土工膜结构缺陷的红外监测研究

以实验室中厌氧反应池土工膜结构为研究对象,通过实验研究的方法,使用基于太阳能热波激励的热成像技术进行高密度聚乙烯(HDPE)土工膜结构缺陷检测的探索性研究。所提方法利用太阳能辐射作为热波激励,验证了利用云层遮蔽导致的太阳能辐射短期波动进行红外结构监测的可行性。此外,基于结构的瞬态变温过程应用红外热图像序列降温过程温度变化累加对比的方法,以增强缺陷区域的温度对比度。研究结果表明,利用太阳能辐射波动观察到的结构瞬态温度响应可用于确定土工膜结构是否存在缺陷。

红外无损检测缺陷尺寸测量方法研究

红外无损检测技术可有效检测金属、非金属、复合材料的内部缺陷,缺陷尺寸是评估缺陷影响的关键参数,本文以半宽高测量算法来实现对缺陷尺寸的半自动测量,首先手动绘制过缺陷中心的直线构成空间像素曲线,采用Savitzky-Golay滤波算法滤波,并自动寻找空间像素曲线半宽高位置,从而实现对缺陷尺寸的测量。通过对塑料试件、碳钢试件、碳纤维复合材料试件研究发现,不同时刻红外图像测量出的缺陷尺寸具有不同的误差,采用清晰时刻红外图像,测量误差在10%内,采用模糊时刻红外图像,测量误差在20%左右,相对于传统手动测量缺陷尺寸,本文方法将有效提高缺陷尺寸测量的精度。

基于CiteSpace的红外热成像技术在证候诊断及疗效评价中应用现状的可视化分析

目的 探究红外热成像技术(IRT)在证候诊断及疗效评价中的临床应用现状。方法 检索中国知网、万方数据知识服务平台和维普网数据库建库至2022年10月收录的IRT在证候诊断及疗效评价中应用的临床研究文献。运用CiteSpace 5.7.R5对纳入文献的作者、机构、关键词进行可视化分析。结果 共纳入文献220篇,1990—2022年发文量总体呈上升趋势,发文量最多的作者是王平,发文最多的机构是天津中医药大学第一附属医院,共发现12个关键词聚类及21个突现关键词。结论 IRT在证候诊断及疗效评价中应用日益广泛,但该领域研究尚未形成稳定的研究团队,缺乏跨地域科研合作,研究力量分散。

基于温升演化的异质材料点焊接头疲劳极限快速预测

针对传统升降法测定疲劳极限试样需求数量多、历时长、耗费大等特点,论述了一种基于温升演化的不锈钢-碳钢异质材料点焊接头疲劳极限快速预测方法。通过对SUS301L-Q235B点焊接头单试样进行逐级应力加载,并借助红外热像仪获取试样实时温升变化,然后基于建立的疲劳极限预测模型计算得到的疲劳极限值为4.883 kN。传统升降法试验测定的疲劳极限值为5.00 kN,预测值与试验值之间误差为2.34%,验证了红外热像法预测点焊接头疲劳极限的精确性,为疲劳极限预测评估提供了一种新思路。

无损检测技术在陶瓷材料检测中的应用

本文简述陶瓷制品的制作要求及材料制作过程中容易产生的缺陷。介绍超声检测、红外热成像检测技术在陶瓷材料检测中的应用。超声检测术适用于检测陶瓷制品生产过程中的各类缺陷;红外成像检测技术更适合工业生产自动化、大批量检测。为今后陶瓷制品的检测及质量把控奠定了基础。

GaN功率放大器MMIC的近结区热阻解析模型

GaN功率放大器单片微波集成电路(MMIC)的热积累问题是制约其进一步高度集成和大功率化应用的主要技术瓶颈,针对该散热问题,提出了GaN功率放大器MMIC的近结区热阻解析模型。在简单多层叠加的热阻解析模型的基础上,细化至芯片的近结区域,引入了位置矫正因子矩阵和耦合系数矩阵,并通过加栅窗的方式建立了芯片近结区的热阻解析模型。该模型考虑了GaN功率放大器MMIC的特点以及衬底的晶格热效应,可以更准确地表征芯片结温。采用红外热成像仪对6种GaN功率放大器MMIC在不同工作条件下进行了热测试,对比仿真和测试结果发现,解析模型的结温预测误差在10%以内,说明该模型可以准确地表征GaN功率放大器MMIC的热特性,进而用于优化和指导电路拓扑设计。

消瘿散结方结合蜡泥灸对甲状腺结节合并乳腺增生患者TSH、E2和红外热成像的影响

目的:观察消瘿散结方联合蜡泥灸治疗甲状腺结节合并乳腺增生的临床疗效。方法:将患甲状腺结节合并乳腺增生的80例患者按照随机数字表法分为观察组(消瘿散结方+蜡泥灸)和对照组(消瘿散结方),连续治疗3个月。观察治疗前后两组甲状腺结节症状积分、乳腺增生症状积分、中医症状积分及促甲状腺激素(thyroid stimulating hormone,TSH)、雌激素(estrogen,E2)水平的变化情况;并通过红外人体表面温度快速筛检仪采集患者甲状腺、乳腺的体表温度和异常红外区域,对比两组的疗效差异。结果:观察组甲状腺结节主症评分、乳腺增生主症评分、中医症状评分较对照组改善显著(P<0.05)。治疗后,观察组TSH、E2水平低于对照组(P<0.05)。观察组在降低甲状腺结节、乳腺增生局部异常升高的温度及缩小异常高温区域方面优于对照组(P<0.05)。结论:消瘿散结方结合蜡泥灸治疗甲状腺结节合并乳腺增生疗效确切,能有效缩小增生结节,改善患者不适症状。

基于红外热成像的涂层厚度检测及均匀性评价

锁相红外涂层厚度检测技术具有非接触、面测量等优势,具有广阔的应用前景。制作变厚度涂层试件对锁相红外涂层厚度检测参数进行优化,建立了锁相红外涂层厚度检测标定曲线,制定了其涂层厚度检测合格要求与均匀性评价方法。最后,通过试验验证了基于锁相红外热成像技术的涂层均匀性评价方法的准确性和有效性。