The surface of Fiber Reinforced Polymer (FRP) concrete is heated with a line laser beam, and the corresponding heat responses are measured by an infrared (IR) camera. Local heat distribution anomalies caused by interfacial debonding between FRP and concrete are automatically traced and detected as defect based on image processing of IR images. Through numerical simulations and lab-scale experiments, the performance of the laser active thermography for the FRP retrofitted concrete inspection was compared with the performance of a halogen lamp based thermography. This comparison shows that the laser active thermography offers a longer inspection range (over 5 m), better damage sensitivity (detecting damage larger than 10 mm diameter), lower power consumption (15W laser excitation), and reduced false alarms due to external noises.

用线激光束加热纤维增强聚合物（FRP）混凝土的表面，并通过红外（IR）摄像机测量相应的热响应。基于IR图像的图像处理，可自动跟踪由FRP与混凝土之间的界面剥离引起的局部热分布异常，并将其检测为缺陷。通过数值模拟和实验室规模的实验，将用于FRP翻新混凝土检查的激光主动热成像技术与基于卤素灯的热成像技术进行了比较。这种比较表明，激光主动热成像技术提供了更长的检查范围（超过5 m），更好的损伤敏感性（检测直径大于10 mm的损伤），更低的功耗（15W激光激发），并减少了由于外部噪声引起的误报。