复合材料红外热波检测图像处理及投影标注技术

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

为实现对复合材料内部缺陷进行无损检测并对缺陷位置进行准确标记,本文提出了红外热波检测投影标注方法。利用红外热像仪获得闪光灯脉冲激励下样品的红外图像序列,并通过时间采样优化的脉冲相位算法进行处理,增强缺陷的检测效果,再通过自动阈值对缺陷位置进行提取并由投影仪将提取结果投射到样品表面。针对投影仪与热像仪视角差异等因素引起的图像畸变问题,本文提出了一种可见-红外相机辅助标定方法,通过辅助相机对投影仪进行标定,建立投影仪与热像仪的空间坐标关系,对缺陷提取结果进行畸变矫正,提高缺陷标记的精确度。实验结果表明,该缺陷检测及标记方法对不同大小缺陷的面积标记误差在10%以内,中心标记误差在3 mm以内,可以对材料内部缺陷进行较为精确的标记。

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.