微间隙焊缝磁光成像小波多尺度融合检测

针对微间隙(小于0.1 mm)对接焊缝,通过对焊件施加感应磁场,并利用法拉第旋光原理构成的磁光传感器,获取焊缝磁光图像.为了获取焊缝的准确位置,研究一种焊缝磁光图像的小波多尺度信息融合边缘检测方法.对焊缝磁光图像进行3层小波分解,获得包含焊缝边缘信息的小波高频图像.根据各尺度高频信息包含的细节丰富度,融合各尺度高频图像,然后用小波模局部极大值对融合图像进行边缘检测,得到抗噪性和连续性好、定位精度高的焊缝边缘,最后进行焊缝跟踪试验.结果表明,磁光图像小波多尺度信息融合是一种有效的焊缝边缘提取方法,适用于磁光成像传感的微间隙焊缝跟踪图像处理过程.

Micro weld detection based on magneto-optical lmaging and wavelet multi-scale fusion

For micro-gap weld joint whose width is less than 0.1 mm, the weldments are magnetized by using an excitation magnetic field. Meanwhile, a magneto optical sensor based on the principle of Faraday magneto effect is applied to acquire the magneto optical images of weld joint. An edge detection method which fuses the wavelet multi-scale information of image is developed to deal with the magneto optical images of weld joint. Three layers wavelet decomposition of the weld magneto optical image is used to obtain wavelet image which contains high frequency information of weld edge. And then it fuses all high frequency images according to the richness of details which contain the high frequency information of each scale. By using wavelet modulus local maxima to detect the edge of fused image, the smooth weld edge with good noise immunity and continuity is obtained. The result of seam tracking test shows that the proposed method is an effective way to extract weld edge and is suitable for the image processing in micro-gap seam tracking based on magneto-optical imaging sensing.