为了得到纳米操作压电陶瓷驱动器高精度的驱动特性,提出一种基于显微视觉的亚像素位移测量方法。本文采用Harris角点初始定位,对标准的栅格图像序列进行角点匹配,获得模板匹配的初始区域。并提出了二元拉格朗日插值与二元非线性Newton-Raphson迭代算法的亚像素位移测量方法,能够在保证良好测量精度的同时有效地减少亚像素匹配中耗时的相关计算。最后使用改进的亚像素图像块匹配方法对实际的压电陶瓷驱动器的驱动特性进行了测量,并与真实结果和理论模型描述结果进行了对比。实验结果表明,该算法位移测量精度高、稳定性好,得到的压电陶瓷驱动特性曲线符合物理分析结果,能够满足高精度的微纳米测量要求。
In order to obtain driving characteristics of the piezoelectric actuator,a sub-pixel displacement measurement method based on micro-vision is proposed. The initial position is solved by the Harris corner location method. The initial template matching region is obtained by corner matching to critena raster image sequence. The sub-pixel displacement measurement method of duality Lagrange interpolation and nonlinear Newton-Raphson iterated algorithm are proposed,which can effectively reduce the time-consuming for sub-pixel matching related calculations to ensure the good measurement accuracy. A modified sub-pixel image block matching method is used to measure the actual driving characteristics of piezoelectric actuators,and the measurement result is compared with the real displacement and PI model. Experimental results show that the algorithm of displacement measurement exhibits high accuracy and good stability. Piezoelectric characteristic curves obtained agree with the results of physical analysis and can satisfy requirements of high-precision measurements of nanomanipulation.