数字图像相关方法中数字散斑场的制作与应用研究

Design and application of digital speckle patterns in digital image correlation method

针对数字图像相关(DIC)实验中,普通喷漆散斑无法满足超高温环境需求,研究了数字散斑场(DSPs)的制作和转移方法。数字散斑场的设计通过矩阵转换确定每个散斑点的圆心坐标,然后给每个圆心坐标施加一个随机度,并由MATLAB软件编程实现。用激光打标技术将其转移到试件表面,通过圆度和面积比分析了散斑的精度,并通过平均灰度梯度法将喷漆散斑和数字散斑场进行对比分析。研究结果表明,运用激光打标技术转移的数字散斑场精度高于普通喷漆散斑且质量稳定。将数字散斑场运用于拉伸和高温焊接实验,实验中散斑随着试件一起变形,没有出现脱落及遇高温融化等现象。

Aiming at the digital image correlation(DIC)experiment,ordinary paint speckle can not meet the requirement of ultra-high temperature environment,the method of designing and transferring the digital speckle patterns(DSPs)is studied.The design of the digital speckle patterns determine the circle center coordinates of each speckle by matrix transformation,and then a random degree is applied to each circle center coordinate,and it is programmed by Matlab.The laser marking technology is used to transfer it to the surface of the test piece.The accuracy of speckles are analyzed by roundness and area ratio,and the paint speckles and DSPs are compared and analyzed by the average speckle gradient method.The results show that the accuracy of DSPs transferred by laser marking technology is higher than that of ordinary spray paint speckle,and the quality is stable.The DSPs is used in the high-temperature welding test.In the test,the speckle is deformed along with the test piece,and no phenomena such as shedding and melting under high-temperature occurred.