激光超声的铝板缺陷可视化检测方法

为了提高激光超声最大振幅C扫描重建图像的质量并精确识别缺陷尺寸，在算法上，提出带通滤波和差分成像相结合的数据处理方法；在实验上分别用不同频率不同角度的超声换能器对扫描激励进行检测确定最优检测参数。实验结果表明：楔块角度为90°超声探头虽然可以有效识别表面缺陷，但楔块角度为45°的超声探头对内部缺陷检测效果更佳；经过滤波和差分处理后的图像质量显著提高；利用处理过的图像计算得到的缺陷尺寸与实际缺陷进行对比，误差在10%以内，进一步说明该方法将在金属板材缺陷检测方面具有广阔应用前景。

Research on Visualization Detection of Aluminum Plate Defects Based on Laser Ultrasound

In order to improve the quality of laser ultrasound images detected by C-scan with maximum peak value and accurately identify defects, a data processing method combining band pass filtering and differential imaging is proposed to enhance image quality. In the experiment, the ultrasonic transducers with different frequencies and different angles are used to detect the laser scanning excitation to determine the optimal detection transducer. The experimental results show that the 45°inclination probe is more effective in identifying internal defects, and the 90°inclination probe can effectively identify surface defects.. After the data processing, the image quality is significantly enhanced, and the outline can be clearly presented. The error of the defect size calculated from the processed image was compared with the actual defect, and the error was less than 10%, which further indicated that the method would have a broad application prospect in the defect detection of metal sheet.