A simplified reconstructing method for the aspheric surface testing based on scanning interference technology is presented. The aspheric normal intersects the optical axis at different points with different angles, which is called normal congruence; a normal congruence can identify an aspheric surface. In this method, the test aspheric surface is shifted along the optical axis to scan the tested aspheric surface: meanwhile a series of interferograms and phase maps are obtained. The angles between the normal lines and the aspheric axis are obtained using the positions of zero-phase points, according to the image-forming principle of the camera. Here, Zernike polynomials are applied to analyze the phase maps and extract the zero-phase points. Finally, the absolute coordinates of the test surface is rebuilt through iterative integration. Because both the system deformation and amplification do not affect the reconstruction result, this method can avoid complicated stitching algorithm in the subaperture stitching interferometric method. Experimental results show that the method has high accuracy and reliability. (C) 2013 Elsevier GmbH. All rights reserved.
Science & Technology
; Physical Sciences
1.Chinese Acad Sci, Inst Opt & Elect, Chengdu 610209, Peoples R China 2.Univ Elect Sci & Technol China, Sch Optoelect Informat, Chengdu 610054, Peoples R China 3.Univ Chinese Acad Sci, Beijing 100049, Peoples R China