Double counting holograms for non - spherical absolute test of
|School||Nanjing University of Technology and Engineering|
|Keywords||Non - spherical absolutely test Computer-generated hologram Graphics deviation Wave|
Interference test , the test results are generally contain systematic errors of measurement , if you want to further eliminate systematic errors on the measurement accuracy , absolute test of the method can be used . Absolute test of multiple measurements according to the mathematical model , these errors from the reference optical path , the system error in the measured surface with respect to the deviation of the ideal surface to separate , effectively improve the shape measurement accuracy . The article first provides an overview of aspheric the basic characteristics and the non - spherical detection methods , the analysis of the the aspherical absolute test of necessity . By comparing the basic characteristics of the spherical and aspherical both spherical absolute inspection method based on the expansion of the the aspheric absolute test methods , and discussed in detail . Absolute test of the method according to the non- spherical , aspherical absolute test of the most critical one device - double counting hologram coding methods and conditions were analyzed , and a summary of their own errors as well as the introduction of error in the measurement of adjustments . The two sets of hologram pattern deviation caused in double counting hologram , the wave front error and frequency are related, such as determining a set of holograms error deduced error of another set of computer generated holograms , in order to verify this point , using own encoding the Twin - Fresnel zone Mirrors ( abbreviated for Twin - FZM ) the experimental verification, the hologram to reproduce both spherical wave , and finally to the experimental results and the calculated results to the difference comparison the results show that it is feasible to meet the design requirements on precision verified aspheric absolute test method .