Image processing and projection annotation technology of composite material infrared thermal wave inspection

In order to realize the non-destructive inspection of the internal defects of composite materials and the accurate marking of the defect positions, this paper proposes a projection labeling method for infrared thermal wave detection. This system uses thermal imaging camera to obtain the infrared image sequence of the sample under the flashlight's pulse excitation, and processes it by the pulse phase thermography optimized by sampling time to enhance the detection effect of the defect, and then uses the automatic threshold to extract the defect position and project the extraction results onto the sample surface through a projector. To solve the problem of image distortion caused by factors such as the viewing angle difference between the projector and the thermal imager, this paper proposes a visible-infrared camera-assisted calibration method. The auxiliary camera is used to calibrate the projector and establish the spatial coordinate relationship between the projector and the thermal imager to correct the distortion of the defect extraction results and improve the accuracy of defect marking. The measurement experiment results show that the defect non-destructive testing and marking method can mark the area of different size defects within 10%, and the center mark errors are within 3 mm, which can accurately mark the internal defects of the material.