[1] [1] E. P. Krotkov. Focusing[J]. Int. J. Comput. Vision,1987,1:223-237

[2] [2] Murali Subbarao,Jenn-Kwei Tyan. Selecting. the optimal focus measure for autofocusing and depth-from-focus[J]. IEEE T. Pattern Anal. Mach. Intell.,1998,20(8):864-870

[3] [3] G. Lighart,F. Groen. A comparison of different autofocus algorithms[C]. IEEE 6th International Conference on Pattern Recognition,1982. 597-600

[4] [4] Mike Heath,Sudeep Sarkar,Thomas Sanocki et al.. Comparison of edge detectors:a methodology and initial study[C]. IEEE T. Comput. Vision Pattern Recogn.,1996. 143-148

[5] [5] Zhang Le,Jiang Wei. Application of multi-resolution analysis in anti-noise capability of auto-focusing algorithm[J]. Acta Optica Sinica,2007,27(12):2150-2154

[6] [6] E. Z. Tihanyi,J. L. Barron.Spatio-temporal edge focusing[C]. IEEE Transactions Proceedings of the 10th International Conference on Pattern Recognition,1990,1:213-216

[7] [7] Sun Jie,Yuan Yuehui,Wang Chuanyong. Comparison and analysis of algorithms for digital image processing in autofocusing criterion[J]. Acta Optica Sinica,2007,27(1):35-39

[8] [8] Chi-Keung Fong,Wai-Keun Cham. Edge model based segmentation[J]. IEEE T. Pattern Recogn.,2004,3:618-621

[9] [9] Linan Fan,Yong Wen,Xinhe Xu. Research on edge detection of gray-scale image corrupted by noise based on multi-structuring elements[C]. IEEE T. Parallel Distrib. Comput.,Application and Technologies,2003,840-843

[10] [10] S. M. Smith,Brady J. Michael. SUSAN:An new approach to low level image processing[J]. Int. J. Comput. Vision,1997,23(1):45-78

[11] [11] Frans C. A. Groen,Ian T. Young,Guido Ligthart. A comparison of different focus functions for use in autofocus algorithms[J]. Cytometry,1985,6:81-91

[12] [12] Kang-Sun Choi,Sung-Jae KO. New autofocusing technique using the frequency selective weighted median filter for video cameras[J]. IEEE T. Consum. Electron.,1999,3(45):820-827