基于最大长度序列的绝对位移精密检测方法

摘要

In order to detect the tiny displacement of the precision mechanism,according to the theory of displacement coding and machine vision technology,the MLS-based visual target schemes are figured out.Based on the algorithms of gray superposition and image binarization,the image of visual targets is processed and the target absolute position is then recognized.Further,the precise positioning is studied based on a phase-fitting method,and thereby,the precision measurement of one dimension absolute displacement is realized with experimental verification carried out.The preliminary experiment results confirms that the MLS-based absolute displacement detection method is effectively capable for one-dimension absolute displacement detection with a positioning accuracy falling in the range of ±2 μm,and exhibits excellent repeatability and robustness,as well as the sound advantage of being free of visual calibration of the CCD camera.%为了检测精密机构的微小位移,根据位移编码与机器视觉技术,提出一种基于最大长度序列(Maximum Length Sequence-MLS)的绝对位移检测方法;该方法设计了基于MLS的绝对位移检测的视觉靶标方案,采用基于灰度叠加及二值化方法进行图像处理和靶标绝对位置识别;研究了基于拟合相位的精密定位方法,实现一维绝对位移的精密检测,并进行实验验证;实验结果表明,该方法可有效实现一维绝对位移检测,定位精度在±2μm范围内,具有良好的重复性和鲁棒性,且无须视觉标定.