Integrated polar microstructure and template-matching method for optical position measurement

This paper presents an integrated polar microstructure and template-matching method for optical position measurement that is developed based on the technology of ultra-precision machining (UPM) and computer vision. For computer vision, this paper makes use of the template-matching method as the basic working principle to match the position on the surface. For UPM, an optical microstructure that is named a ‘polar microstructure’ is purposely designed and fabricated by ultra-precision diamond machining technology to provide the high resolution of the position measurement. To demonstrate the performance of the proposed method for optical position measurement, a high-precision multi-sensor coordinate measuring machine was used to test the position accuracy and the length uncertainty for the two axes of this positioning method. The experimental results show that the average length uncertainty and the corresponding standard deviation errors are 109.6 nm and 76.4 nm on the X-axis, and 91.8 nm and 69.7 nm on the Y-axis, respectively.