焊接动态位移场的激光电子散斑法测量

Measurement of welding dynamic displacement field by ESPI

为提供一种能够全场测量整个焊接过程动态位移场的工具,建立了激光电子散斑法测量系统.应用于实际TIG焊接过程中,获得了焊接位移场的散斑原始图像.利用自开发软件,对图像进行灰度变换和直方图均衡化处理后,采用频域同态滤波的方法对图像进行降噪滤波处理.经降噪、二值化、细化、平整、拟合、标定等一系列处理后,即可自动生成相对动态位移场.结果表明,激光电子散斑法能够胜任焊接动态位移场的测量,且具有非接触、测量精度高、对环境的防震要求低、可在明光下操作、能进行全场测量的特点.

In order to offer a full-field measurement tool of the welding dynamic welding displacement field during the whole welding process, a system of Electronic Speckle Pattern Interferometry （ESPI） was built.The system was applied into a TIG welding process and the original speckle patterns during welding were obtained. After the gray transformation and the histogram equalization, these images were filtered by a frequencydomain homomorphic filter, hence noises in the images were greatly reduced. Through a series of processes such as noise reduction, binary, refinement, smoothness, fitting, and calibration, the relative welding dynamic displacement field could be acquired automatically. The results show that the ESPI can fulfill the task of welding dynamic welding displacement measurement, and it has merits of non-contact, high precision, strong parasitic light resistance, and full-field measurement.