Sub-microscale precision repeatability position measurement using integrated polar microstructure and feature extraction method

This paper presents a novel vision-based way to achieve repeatability measurement with sub-microscale precision, two degrees of freedom, small footprint, easy installation, and low cost. This research theoretically analyzes the pixel intensity distribution mechanism of surface topography and develops the non-periodic pattern referred to be polar microstructure to achieve sub-microscale resolution. Considering polar microstructure features, this paper also develops an image matching-based measurement algorithm, leading to the integrated polar microstructure and feature extraction (PMFE) repeatability measurement method. To demonstrate the performance of PMFE, comparison experiments with the laser interferometer method were conducted. The experimental results show the measurement uncertainty of the PMFE method is 0.58 μm in the X direction and 0.33 μm in the Y direction respectively compared with the laser interferometer method. These results indicate that the PMFE system is reliable and show the potential application in the measurement of machine tool repeatability. is reliable and show the potential application in the measurement of machine tool repeatability.