[7] Krotkov E P. Active Computer Vision by Cooperative Focus and Stereo [M]. Berlin: Springer-Verlag,1989.
[8] Schlag J F, Sanderson A C, Neuman C P, et al. Implementation of Automatic Focusing Algorithms for a Computer Vision System with Camera Control [R]. Carnegie Mellon University: CMU-RI-TR-83-14,1983.
[9] Subbarao M, Tyan J K. Selection the Optimal Focus Measure for Autofocusing and Depth from Focus [J]. IEEE Transactions on Pattern Analysis and Machine Intelligence, 1998, 20(8): 864-870.
[10] Jarvis R A. Focus Optimization Criteria for Computer Image Processing [J]. Microscope, 1976, 24(2): 163-180.