材料表面裂纹是导致构件破损、影响物理特性的原因之一。本文采用红外热像显微镜研究了材料表面裂纹检测的问题。首先在铝薄板上设计不同方向、不同长度的表面裂纹。由于裂纹处与正常区域之间的辐射能力的差异，造成表面温度场的不均匀性。红外显微镜捕捉到物体表面辐射，探测出不同方向的表面裂纹，引入标尺实现了裂纹长度的定量检测并做了误差分析。再研究了碳纤维层压板冲击损伤的表面裂纹，通过图像拼接完整显示了冲击损伤裂纹的形貌和走势，运用扫查法提取裂纹。研究结果表明红外显微镜具有探测材料表面自发辐射的能力，可用于不同材质表面裂纹的探测。

The material surface crack is one of the reasons for the damage and poor physical properties of the concerned component. In this paper, the surface crack detection of materials was studied using infrared thermal imaging microscope. Firstly, surface cracks with different lengths along different directions were designed on aluminum sheets. A non-homogeneity of the surface temperature field was caused by the difference of radiation through the cracks and the normal region. Infrared microscopes, in general, can capture the surface radiation of the object and thereby detect the surface cracks in different directions. Furthermore, quantitative detection of the crack length was realized by introducing a ruler into the thermal image, and the error was then analyzed. Secondly, the surface crack due to impact damage of carbon fiber laminated board was studied. The shapes of the impact damage cracks and their trend were exhibited via image stitching while the cracks were extracted by the scanning method. The results show that the infrared microscope has the ability to detect the spontaneous radiation of the material surface, therefore, can be used for the detection of surface cracks in different materials.