Innovative developments of infrared thermography for non destructive evaluation

在材料的热无损评价（TNDE）中，外部热刺激被带到待检测的部件上，并且对该刺激的响应（用红外摄像机记录）允许确定该部件的次表面结构，揭示潜在的次表面缺陷的存在，例如空隙、分层、孔隙。在TNDE中，无论是在刺激阶段还是在信号记录和解释阶段，都会出现许多问题。拟议的研究计划的目标是面向解决这些问题，他们是在我们的研究活动的长期目标的连续性。目前提出的研究计划为新的和重要的研究活动提供了良好的潜力：* 刺激/记录阶段：其目的是深入研究，通过热模拟和实验的影响，各种检查刺激程序（光学加热，感应涡流加热，超声加热），同时通过修改部件中发射的热波的光谱内容来开发自适应加热，以最大化缺陷可见性。* 解释阶段：我们的目标是追求脉冲相位热成像（PPT）的发展，其中频率分析能够计算受噪声影响较小的相位图像，并允许更深的探测。一个建议的增强PPT是使用小波变换保持访问必要的时间信息，以提取定量信息的地下文物的利益。* 自动/辅助诊断：为了提高可靠性和便于工业实施，提出了涡流数据和热感应加热的融合以及在红外图像处理中使用“偏斜度”结合自动检测。研究生将积极参与这里介绍的工作，这是有希望的，因为它将为TNDE社区和工业用户带来新的想法。拟议活动的意义有两方面。工作的基础有很强的理论基础，而所提出的方案的结果很好地应用于例如行业，以确保有价值的转移。

In Thermal Non Destructive Evaluation (TNDE) of materials, an external thermal stimulation is brought to the component to be inspected and response to this stimulus, recorded with an infrared camera, allows to determine the subsurface structure of this component revealing the presence of potential subsurface defects such as voids, delaminations, porosities. Many problems arise in TNDE either at the stimulation stage or at the signal recording and interpretation stage. Objectives of the proposed research program are oriented towards solution of these problems and they are in continuity with long term goals of our research activities. The present proposed research program offers good potential for novel and significant research activities: * Stimulation/recording stages: The objectives are to study in depth, through thermal modeling and experiments the effects of various inspection stimulation procedures (optical heating, inductive - eddy current - heating, ultrasonic heating) while developing adaptive heating by modifying the spectral content of the launched thermal waves in the component to maximize defect visibility. * Interpretation stage: The objectives consist to pursue development of the pulsed phase thermography (PPT), in which a frequency analysis enables to compute phase images less affected by noise and allowing deeper probing. A proposed enhancement to PPT is the use of the Wavelet transform maintaining access to the time information necessary to extract quantitative information of subsurface artifacts of interest. * Automatic/aided diagnosis: to improve reliability and to facilitate industrial implementation, fusion of eddy current data and thermoinductive heating and the use of "skewness" in infrared image processing combined to automatic detection are proposed. Graduate students will be strongly involved in the work presented here which is promising since it will bring fresh ideas to the TNDE community and industrial users. The significance of the proposed activities is two-fold. The basis of the work has a strong theoretical foundation, while results of the proposed program are well applied for instance in industries in order to ensure valuable transfer.