发射率对半导体器件显微红外测温结果的影响

为了确认半导体器件较低的发射率对显微红外测温结果的影响,采用研制的半导体材料和金属材料靶标进行了一系列验证实验,分析了发射率对显微红外热像仪测温准确度的影响.研制了带有铂电阻结构的GaAs材料靶标和Au材料靶标,用显微红外热像仪对黑体和研制的2种靶标进行了不同温度下的测试,在110℃条件下,黑体、GaAs、Au 3种材...     

显微热成像系统行处理迭代超分辨力处理研究

针对已研制光学微扫描显微热成像系统空间分辨力较低的问题,基于改进的频域图像配准技术和改进的行处理迭代超分辨力算法,提出了显微热成像系统光学微扫描改进行处理迭代超分辨力图像处理方法。给出了该方法的原理及步骤,采用不同重构方法针对可见光和红外图像进行了仿真研究,给出了评价参数和结论。利用光学微扫描显微热成像系统采集低分辨力显微热图像序列进行了超分辨力处理实验,实验结果表明本文提出方法的有效性,光学微扫描显微热成像系统的空间分辨力得到提高,可应用于需要显微热分析的场合。该方法还可以应用于其它不可控光学微扫描成像系统中,具有广泛的应用前景。     

大口径高发射率面型黑体辐射源的研制

黑体辐射源作为定标标准器,在红外测量设备的辐射定标中具有重要作用。为应对大口径红外测量设备的辐射定标工作需求,设计了1台辐射面积为400mm×400mm的面型黑体辐射源。采用多路控温和连接固定冷源的方式对黑体进行温度控制;通过热仿真确定合适的传热模型,同时结合高发射率涂层工艺与辐射面的结构设计使黑体具备高发射率,辐射面有效发射率可达到0.992;在真空环境下,利用标准铂电阻温度计测量得到黑体辐射面源的温度均匀性偏差最大为0.101K,稳定性平均值为0.018K/10min,该黑体辐射光源能够满足现阶段大口径红外测量设备的使用需求。     

H500型红外遥感定标高精度真空黑体辐射源的研制

对中国计量科学研究院研制的温度范围覆盖-93~220℃的H500型红外遥感定标高精度真空黑体辐射源进行了介绍。采用圆柱圆锥黑体腔和双层4段PID控温,在真空低背景(液氮冷却)环境下对该黑体进行了性能测试,在大气室温环境下,利用控制环境辐射反射比发射率测量方法测量了黑体空腔发射率和利用红外标准辐射温度计测量空腔底部温度均匀性等指标。实验结果表明,该黑体辐射源升温速率为1℃/min下,控制到温度点的稳定时间优于50 min,并且10 min内的温度稳定性在0.01℃以内;黑体温度设置在20℃、30℃和50℃下空腔发射率的测量结果分别为0.9965、0.9966和0.9963;其黑体底部温度均匀性优于0.03℃;在整个温度区域内扩展不确定度优于0.1℃(k=2)。     

关于提高红外筛检仪测量精度的研究

本文从非制冷焦平面探测器成像技术、参考黑体、温度标定三个方面,说明了在较低温度下提高红外筛检仪测量精度的方法.     

空间跟踪与监视系统预警探测单元的技术特性分析

对空间跟踪与监视系统预警探测单元的探测视场、成像像素规模、空间分辨力、光学增益等光学系统性能进行了逆向工程解算;基于目标与背景的短波红外辐射特性,对该预警探测单元的工作波段进行了定量分析,提出了其预警探测单元并非工作在传统预警卫星常用的低大气透过率波段(2.5~2.9μm)的新观点。计算结果表明,在强背景噪声条件下,预警探测单元采取高大气透过率波段(2~2.4μm)的选通滤波措施,可获得最优探测能力。     

新型精密光电高温计

根据温标传递的特点和需要,设计了新的精密光电高温计。该高温计测量黑体的光谱辐射亮度,结合有效波长原地测量技术,直接依据Planck辐射定律计算被测温度,具备单一参考点分度确定温标的技术能力。该高温计测温范围为800℃～2200℃,在小目标和窄谱带的测量条件下,具有分辨率高、辐射源尺寸影响小、自动化测量等特点。在900℃时温度分辨率为0 01℃。在800℃～2200℃温度范围内,置信水平为0 99时,扩展不确定度为1 0℃～2 4℃。结构参数和性能测试表明,精密光电高温计不仅适用于温度精密测量,而且可作为温标的传递标准。     

红外体表温度计示值修正值测量结果的不确定度评定

笔者结合校准某高校保障复学送检的580台红外体表温度计的工作实践,通过对红外体表温度计示值修正值测量不确定度的分析和评定,以期为校准活动和仪器日常使用提供技术支持。一、概述1.测量依据:JJF1107-2003《测量人体温度的红外温度计校准规范》。2.测量环境条件:温度18℃~22℃,湿度(30~70)%RH,无强环境辐射,无强空气对流。3.测量对象:红外体温计(TD133),分辨力0.1℃,MPE=±0.3℃。     

辐射温度计校准设备准标准黑体技术探讨及实际测量应用

标准黑体是校准辐射温度计的主要设备,但迄今为止对黑体辐射技术的研究仍在不断的完善之中,本文论述了通过准确标定标准黑体的辐射温度,来验证黑体发射率的技术探讨及在实际测量应用中总结出的关于辐射温度计校准中存在的几个问题。     

吊舱整流罩自身红外辐射对目标测试的影响

结合某吊舱加装红外热像仪的使用,基于红外热像仪测试目标辐射亮度、辐射强度的功能,提出了在目标红外辐射特性测试中扣除整流罩影响的方法 ,并在实验室利用黑体、整流罩、长波红外热像仪,测试了整流罩的波段透过率,给出了某吊舱扣除整流罩影响的修正公式,并在型号测试中应用,取得了良好的效果。     

Methodology for Mapping the Residual Stress Field in Serviced Rails Using LCR Waves

Thermal barrier coatings (TBCs), as effective thermal protection separating the substrate from high-temperature combustion gases and reducing the substrate temperature, are widely used in aerospace and other fields. During the service cycle of life, surface crack defects, interface disbond defects, and coating thickness changes are the main non-destructive testing (NDT) objects of TBCs. In this paper, the main active infrared thermography NDT techniques including the optical infrared thermography testing, the ultrasonic infrared thermography testing, and the microwave thermography testing techniques are reviewed. Through the summary and highlight of the detection principle and application status of these state-of-the-art techniques, the development of the active infrared thermography DNT technique in TBCs is presented. By comparing the sensitivity, advantages, and disadvantages of the techniques in TBC NDT, can provide a significant reference for researchers to choose an appropriate method. It is noteworthy that fabrication techniques of artificial defects for calibration of the active infrared thermography NDT technique inspection of TBC systems are also reviewed. Moreover, future trends in NDT for the TBC system based on the active infrared thermography NDT technique are also discussed and analyzed.

     

Corrosion Detection in Pipelines Using Infrared Thermography: Experiments and Data Processing Methods

This article summarizes the main results of an investigation about the corrosion detection in pipelines by infrared thermography, a non-destructive testing and evaluation technique that allows a reliable and fast analysis of large surfaces. The experimental work has been carried out in laboratory on a specimen that has been manufactured using a piece of a real pipeline system for oil transportation. Defects of different kinds have been artificially introduced in such a system to be tested by thermography. The objective is the detection and analysis of the presence of water in the pipeline jacketing system, that is the cause of the corrosion under insulation. Standards indicate thermography as a technique for the detection of this last phenomena, even though a precise procedure is not defined up today. This work aims at contributing in the specification of such a procedure.     

Radiance temperatures at 1500 nm of niobium and molybdenum at their melting points by a pulse-heating technique

Radiance temperatures at 1500 nm of niobium and molybdenum at their melting points were measured by a pulse-heating technique. The method is based on rapid resistive self-heating of the strip-shaped specimen from room temperature to its melting point in less than I s and measuring the specimen radiance temperature every 0.5 ms with a high-speed infrared pyrometer. Melting of the specimen was manifested by a plateau in the radiance temperature-versus-time function. The melting-point radiance temperature for a given specimen was determined by averaging the measured values along the plateau. A total of 12 to 13 experiments was performed for each metal under investigation. The melting point radiance temperatures for each metal were determined by averaging the results of the individual specimens. The results for radiance temperatures at 1500 nm are as follows: 1983 K for niobium and 2050 K for molybdenum. Based on the estimates of the uncertainties arising from the use of pyrometry and specimen conditions, the combined uncertainty (two standard-deviation level) in the reported values is ± 8 K.Paper presented at the Fourth International Workshop on Subsecond Thermophysics, June 27–29, 1995, Köln, Germany.     

Surface temperature correction for active infrared reflectance measurements of natural materials

Land surface temperature algorithms for the moderate resolution imaging spectroradiometer satellite instrument will require the spectral bidirectional reflectance distribution function (BRDF) of natural surfaces in the thermal infrared. We designed the spectral infrared bidirectional reflectance and emissivity instrument to provide such measurements by the use of a Fourier transform infrared spectrometer. A problem we encountered is the unavoidable surface heating caused by the source irradiance. For our system, the effects of the heating can cause a 30% error in the measured BRDF The error caused by heating is corrected by temporally curve fitting the radiance signal. This curve-fitting technique isolates the radiance caused by reflected irradiance. With this correction, other factors dominate the BRDF error. It is now ~5% and can be improved further. The method is illustrated with measurements of soil BRDF.     

Non-destructive Testing by Infrared Thermography Under Random Excitation and ARMA Analysis

Photothermal thermography is a non-destructive testing (NDT) method, which has many applications in the field of control and characterization of thin materials. This technique is usually implemented under CW or flash excitation. Such excitations are not adapted for control of fragile materials or for multi-frequency analysis. To allow these analyses, in this article, the use of a new control mode is proposed: infrared thermography under random excitation and auto regressive moving average analysis. First, the principle of this NDT method is presented. Then, the method is shown to permit detection, with low energy constraints, of detachments situated in mural paintings.     

Measurement of Temperature Increment in Compressive Quasi-Static and Dynamic Tests Using Infrared Thermography

Abstract:  During the plastic deformation of metals, part of the mechanical energy is retained in the material as plastic deformations and the rest is converted to heat. A temperature increment is a measure of the heat energy generated in the tested specimen. This temperature can be detected by measuring the infrared (IR) radiation emitted by the specimen surface. This study describes an attempt to improve the experimental procedure using IR thermography to measure the temperature increment as a function of the plastic strain of the studied materials. Tests were carried out under quasi-static and dynamic load conditions (using a universal testing machine and a Split Hopkinson pressure bar). The method is applied on an Al alloy (Al6082), a Mg alloy (ZC71) and the same Mg alloy reinforced with ceramic particles (SiC, 12 vol%). The emissivity measurement of the studied materials is detailed, as well as the method of synchronising the IR camera with the testing machines. Finally, the influence of test conditions on the measured temperature is analysed.     

Application of full-surface view in situ thermography measurements during ultrasonic fatigue of cast steel G42CrMo4

In the present investigation a full-surface view in situ thermography method is adapted to an ultrasonic fatigue testing system. Full-surface view in situ thermography measurements were successfully performed in the high cycle fatigue and in the very high cycle fatigue regime on cast steel G42CrMo4 in the quenched and tempered state. The method enables the monitoring of the entire cylindrical specimen circumference during fatigue testing by infrared temperature field measurements with one thermocamera and two mirrors. Moreover, by correlating fractography and thermography the precise determination of the location of the crack initiation site and the time of final crack growth is possible. The technique is applied to study crack initiation at non-metallic inclusions in the investigated cast steel specimens. Moreover, the effect of a novel carbon-bonded metal melt filter coated with a functionalized spinel (MgAl₂O₄) coating is evaluated by ultrasonic fatigue testing in combination with the full-surface view in situ thermography technique and subsequent scanning electron microscopy.     

Infrared thermography applied to testing of external walls

A qualitative picture of heat leakage-distribution can be provided from temperature distribution of wall surfaces. This measurement is facilitated considerably in investigating on-site when a new technique, “infrared thermography” is used. An infrared camera works on the principle of transforming infrared radiation from an object to electric signals which are transformed to a black and white “thermal picture” in an oscilloscope. If thermograms are compared with anticipated temperature distributions for the wall surfaces being studied one can decide if the performance of the walls corresponds to the building plans or not. A manual for thermographing buildings has been worked out by the Swedish National Institute for Materials Testing.     

Thermodynamic product retrieval methodology and validation for NAST-I

The National Polar-Orbiting Operational Environmental Satellite System (NPOESS) Airborne Sounder Testbed (NAST) consists of two passive collocated cross-track scanning instruments, an infrared interferometer (NAST-I) and a microwave radiometer (NAST-M), that fly onboard high-altitude aircraft such as the NASA ER-2 at an altitude near 20 km. NAST-I provides relatively high spectral resolution (0.25-cm(-1)) measurements in the 645-2700-cm(-1) spectral region with moderate spatial resolution (a linear resolution equal to 13% of the aircraft altitude at nadir) cross-track scanning. We report the methodology for retrieval of atmospheric temperature and composition profiles from NAST-I radiance spectra. The profiles were determined by use of a statistical eigenvector regression algorithm and improved, as needed, by use of a nonlinear physical retrieval algorithm. Several field campaigns conducted under varied meteorological conditions have provided the data needed to verify the accuracy of the spectral radiance, the retrieval algorithm, and the scanning capabilities of this instrumentation. Retrieval examples are presented to demonstrate the ability to reveal fine-scale horizontal features with relatively high vertical resolution.