Open AccessFast and accurate auto-focusing algorithm based on the combination of depth from focus and improved depth from defocus
Author(s) -
Xuedian Zhang,
ZhaoQing Liu,
Mawei Jiang,
Min Chang
Publication year - 2014
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.22.031237
Subject(s) - focus (optics) , depth of focus (tectonics) , computer science , autofocus , depth of field , software , optics , computer vision , algorithm , artificial intelligence , physics , geology , paleontology , subduction , tectonics , programming language
An auto-focus method for digital imaging systems is proposed that combines depth from focus (DFF) and improved depth from defocus (DFD). The traditional DFD method is improved to become more rapid, which achieves a fast initial focus. The defocus distance is first calculated by the improved DFD method. The result is then used as a search step in the searching stage of the DFF method. A dynamic focusing scheme is designed for the control software, which is able to eliminate environmental disturbances and other noises so that a fast and accurate focus can be achieved. An experiment is designed to verify the proposed focusing method and the results show that the method's efficiency is at least 3-5 times higher than that of the traditional DFF method.