激光致熔池图像获取及质心提取方法研究

The Research of Molten Pool Image Acquiring and Centroid Calculation Method in the Laser Welding Processing

激光焊接已广泛应用于航空航天、汽车、船舶、医疗器械等领域关键部件的制造。为保证焊接质量,可使用工业CCD相机在焊接过程中实时检测熔池中心与焊缝间的偏差,并根据偏差进行调整。因此,首先要对激光致熔池获取和质心提取方法进行研究。由于激光焊接中熔池温度高,应用工业CCD相机直接拍摄熔池的图像无法进行图像处理。为拍摄熔池清晰图像,在对熔池辐射光线特性进行分析的基础上,结合工业CCD光谱响应特性,确定合适的采集熔池图像所需光谱波长范围。应用镜头前放置了所求波长滤光片的工业CCD相机,拍摄直接作用在304钢板上的激光致熔池图像,并对熔池边缘识别和熔池质心计算方法进行了研究。实验表明,所提出激光致熔池提取方法及质心计算方法有效。

Laser welding had been widely used in the fields of manufacturing key parts of aeronautics and astronautics,automobile,watercraft and medical devices. For ensuring the welding quality,the deviation in the image between the center of molten pool and weld seam which were acquired by the industrial CCD camera was employed to adjust the welding position.Thus,the image of molten pool should be obtained. However,the images of high temperature molten pool which were directly shot by CCD camera could not be applied for image processing. In order to acquire the clear images of molten poor,the wavelength of the filter which would be installed in front of the camera lens should be ensured by analyzing the light features which was radiated by the molten pool and the spectral response characteristic of the industrial CCD camera. According to the acquired images of molten pool on the 304 steel plate created by the laser beam,the edge recognition and the center of molten pool calculation method were researched. Experiment shows that the edge recognition and the center of molten pool calculation method were effective.