Algorithms of wavefront generation for aspheric surface measurement

Abstract

For aspheric surface measurement with wavefront sensing technology, after obtaining the slope or curvature as the measurement raw data, the data processing algorithm must be re-studied for high performance in practical application. This paper designs, analyzes and compares five different algorithms to generate wavefront for aspheric surface measurements, especially for practical measurements with noises and missing data. Simulation and experimental results show that in ideal condition without any noise in the system, direct fitting yields perfect results without error; the algorithms including Southwell reconstruction achieve better results under practical conditions, where there exist real issues such as noise and abnormal data. Reconstruction is therefore an essential step as it significantly improves the measurement stability and reliability, and enables the system feasible for practical applications. Furthermore, Southwell algorithm is extended for applications with missing data, which is most likely happen when the surfaces to be measured possess large dynamic range.