超声散斑数字相关法应用于刚体面内转动测量的研究

在激光数字散斑相关法测量理论的基础上,阐述了超声散斑相关法测量的基本原理,并建立了相应的超声散斑数字相关实验分析系统。在实验分析时,首先应用模拟测量的方法对刚体面内转动对散斑场相关性的影响进行了分析;然后应用实验测量的方法再对此进行了分析;最后对刚体未知面内转角进行了实测。实验结果表明,刚体面内转动可测量的最大转角为9°,当转动角度为10°时,误差大于9%。实验中分别应用了爬山搜索法和相关系数拟合法来分别搜索整像素的位移和亚像素的位移。

A Study on the In-Plane Rotation Measurement of a Rigid Object with the Ultrasonic Speckle Correlation Method

The principles of ultrasonic speckle digital correlation method is proposed based on the theorem of laser speckle digital correlation method, and an analysis experimental system of ultrasonic speckle digital correlation was built up. In the experimental analysis, the influence of in-plane rotation of a rigid body on the correlation of the ultrasonic speckle fields was firstly analyzed by using analog measurement. Then, the influence was analyzed by using the practical experimental measurement. Finally, the in-plane rotation of a rigid body was practically measured. The experimental results show that the maximum rotation angle, which can be measured by using the ultrasonic speckle digital correlation method, is 9 degrees, and when the rotation angle reaches 10 degree, the measurement error is larger than 9%. In the experiment, a mountain-climbing searching method and a curve-fitting method were employed to determine the integral pixel displacement and the sub-pixel displacement respectively.