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Proceedings Paper

Auto-measuring system of aero-camera lens focus using linear CCD
Author(s): Yu-ye Zhang; Yu-liang Zhao; Shu-juan Wang
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Paper Abstract

The automatic and accurate focal length measurement of aviation camera lens is of great significance and practical value. The traditional measurement method depends on the human eye to read the scribed line on the focal plane of parallel light pipe by means of reading microscope. The method is of low efficiency and the measuring results are influenced by artificial factors easily. Our method used linear array solid-state image sensor instead of reading microscope to transfer the imaging size of specific object to be electrical signal pulse width, and used computer to measure the focal length automatically. In the process of measurement, the lens to be tested placed in front of the object lens of parallel light tube. A couple of scribed line on the surface of the parallel light pipe’s focal plane were imaging on the focal plane of the lens to be tested. Placed the linear CCD drive circuit on the image plane, the linear CCD can convert the light intensity distribution of one dimension signal into time series of electrical signals. After converting, a path of electrical signals is directly brought to the video monitor by image acquisition card for optical path adjustment and focusing. The other path of electrical signals is processed to obtain the pulse width corresponding to the scribed line by electrical circuit. The computer processed the pulse width and output focal length measurement result. Practical measurement results showed that the relative error was about 0.10%, which was in good agreement with the theory.

Paper Details

Date Published: 18 September 2014
PDF: 5 pages
Proc. SPIE 9282, 7th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, 92822A (18 September 2014); doi: 10.1117/12.2068563
Show Author Affiliations
Yu-ye Zhang, Naval Aeronautical Engineering Institute (China)
Yu-liang Zhao, Naval Aeronautical Engineering Institute (China)
Shu-juan Wang, Naval Aeronautical Engineering Institute (China)


Published in SPIE Proceedings Vol. 9282:
7th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment
Yudong Zhang; Wei Gao, Editor(s)

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