In order to obtain a high resolution image required for ultra-precision measurement of microstructural object, a new approach is proposed for 3D microstructures. It uses the modulation transfer function with defocus aberration based on the ambiguity function and stable phase principle to achieve an optical phase filter, and utilizes generalized a spheric phase optical element to encode defocus images, and uses deconvolution technology to recover the images. In comparison with conventional optical system, the phase filter used in the optical system can make focal spot smaller when measure object defocusing, eliminates the effect of the defocus aberration, and improves the defocused property. Numerical results indicate the designed phase filter can improve lateral resolution of optical system, and the axial resolution of the optical system is not affect by the filter and defocus aberration. For different defocus plate, the phase filter can make character of modulation transfer function of lateral direction uniform approximation.

Date Published: 31 January 2013
PDF: 6 pages
Proc. SPIE 8759, Eighth International Symposium on Precision Engineering Measurement and Instrumentation, 875920 (31 January 2013); doi: 10.1117/12.2014341

Published in SPIE Proceedings Vol. 8759:
Eighth International Symposium on Precision Engineering Measurement and Instrumentation
Jie Lin, Editor(s)