Efficient auto-focus algorithm for optical measurement system

Jun Ni; Min Wei; Jiahu Yuan; Qinzhang Wu

doi:10.1117/12.828802

20 May 2009 Efficient auto-focus algorithm for optical measurement system

Jun Ni, Min Wei, Jiahu Yuan, Qinzhang Wu

Proceedings Volume 7283, 4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment; 728344 (2009) https://doi.org/10.1117/12.828802
Event: AOMATT 2008 - 4th International Symposium on Advanced Optical Manufacturing, 2008, Chengdu, Chengdu, China

Abstract

To keep image captured by optical measuring system in focus, pixel-based auto-focusing is a long-standing topic in the literatures. Sharpness function is the mathematical description of image sharpness. It plays an important role for realizing robust auto-focusing of optical measuring system. In optical tracking measuring system, the size of moveable object image always is variational. Under this condition, the existing sharpness functions will not work well for autofocus system. In this paper, an efficient sharpness function based on the number of variable threshold gradients is proposed. This auto-focus algorithm calculates the number of gradients bigger than threshold, while threshold is variable according to image. By using this auto-focus algorithm to optical measuring system, the robust and reliability of autofocus system are improved. Practical applications illuminate the proposed approach is feasible and effective.

Citation Download Citation

Jun Ni, Min Wei, Jiahu Yuan, and Qinzhang Wu "Efficient auto-focus algorithm for optical measurement system", Proc. SPIE 7283, 4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, 728344 (20 May 2009); https://doi.org/10.1117/12.828802

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