焊接激光束致熔池中心计算方法研究

Laser Molten Pool Center Calculation Method

根据激光焊接过程中焊缝位置形成熔池温度高、辐射光线强的特点,利用带通滤光片滤除熔池辐射光线及飞溅物辐射光线后拍摄的焊缝图像,对焊接过程中激光致熔池的提取方法进行了研究.首先根据熔池图像的灰度值初步确定熔池中心,由该中心向设定方向搜索得到熔池的像素级边缘;然后由像素级边缘点附近一定区域内的像素灰度求亚像素边缘点的位置;最后将亚像素边缘点拟合为圆,拟合圆的圆心即为熔池中心.试验表明,所提出的方法能利用拍摄的熔池图像识别熔池中心.

Because of the high temperature of molten pool in laser welding processing, the acquiring method of molten pool and the compute method of weld seam should be researched. The bandwidth range of filter was en-sured. Thus, the clear images of molten pool could be obtained. There were several steps that were required to obtaining the center of molten pool. Firsdy, the initial center of molten pool was calculated by the grey value. Then, the pixel edge of molten pool could be search from the initial center. Secondly, each sub-pixel edge of the molten pool was calculated separately using the pixels around the pixel edge in a certain region. Lastly, the molten pool center could be obtained by circle fitting using sub-pixel edges. Experiment shows that the proposed method can be applied to acquir the image of molten pool and calculate the center.