Share Email Print
cover

Proceedings Paper

Auto-focusing technology for photoelectric measurement system
Author(s): Tao Lei; Sihan Yang; Yong Zhang; Qinzhang Wu
Format Member Price Non-Member Price
PDF $17.00 $21.00

Paper Abstract

Automatic focusing (AF) is a key technology of measuring TV capturing the clear objective image in photoelectric measurement system. It is viable to enhance the performance of measuring TV through focusing effectively and quickly. In the process of maneuvering target tracking, the background and the feature of targets change from time to time, and the reliability of AF is highly required. Firstly, conditions for starting AF need to be investigated. The relation between degree of definition and edge acutance is proved by experiments. Combined with the sharpness value, it decides whether to begin AF. Secondly, it needs focusing quickly and exactly after starting AF. The accuracy and efficiency of the sharpness function is another key factor of AF. By comparing some favorable sharpness functions, normalized variance and square-gradient functions are employed based on focus windows. Thirdly, the optimized mountain-climb searching algorithm based on the defocusing extents and the adaptive searching step size is proposed. Experiments show the algorithm proposed improves the speed and reliability of AF.

Paper Details

Date Published: 20 May 2009
PDF: 6 pages
Proc. SPIE 7283, 4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, 728346 (20 May 2009); doi: 10.1117/12.828804
Show Author Affiliations
Tao Lei, Institute of Optics and Electronics (China)
Graduate Univ. of the Chinese Academy of Sciences (China)
Sihan Yang, Chengdu Univ. of Technology (China)
Yong Zhang, Graduate Univ. of the Chinese Academy of Sciences (China)
Qinzhang Wu, Institute of Optics and Electronics (China)


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)

© SPIE. Terms of Use
Back to Top