We present a novel strategies and a prototype for large optical surfaces test with subaperture stitching. The kinematics model with six degrees of freedom is built to determine the initial configuration of each subaperture, according to the records of nulling motion. An alignment error model based on wavefront aberrations is established for compensation and error separation. Subapertures are primarily stitched by homogeneous coordinate transformation, least square method and Zernike polynomial fitting. Then an error-separation matrix of stitching model is developed to analysis the characteristics and effects of alignment error on test results. The expressions of the alignment errors for aspheric surface testing are built based on motion structure and wavefront aberrations theory. So the alignment errors can be separated and compensated efficiently. Subapertures are then simultaneously stitched by minimizing deviations among the overlapping region, as well as deviations from the nominal surface. As a result, precise prior knowledge of the nulling and alignment motion, which is of six degrees of freedom, is no longer required. Simulations and experiments are given to verify the validity and precision of the proposed algorithm. The result shows that the proposed method with alignment compensation is quite efficient.

Date Published: 20 May 2009
PDF: 5 pages
Proc. SPIE 7283, 4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, 72830F (20 May 2009); doi: 10.1117/12.828598

Published in SPIE Proceedings Vol. 7283:
4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment
Yudong Zhang; James C. Wyant; Robert A. Smythe; Hexin Wang, Editor(s)