Auto focusing has been implemented in many
applications for decades. However, challenges still exist in
design of high speed and reliability of a focusing algorithm
under a variety of microscopic views. The clarity of images
measured by a method is generally varying in hill-shaped
manner with respect to lens positions at a focus region, but the
signal-to-noise ratio of the measure is low at a far-off focused.
This will limit the working range of focusing. This paper
proposes a new method by integrating multiple measures for
near and far-off focused. Monotonous variation of individual
measures is integrated and used for expanding the working
range of focusing control with adaptation of step size. Views
for focusing under x50 microscopic lens using the proposed
method are illustrated in this study. The working range is
expanded to be 50 times of depth of field from focused.
Feasibility of the proposed method is investigated on a
practical PC-based system. Two case studies are provided to
demonstrate the feasibility.
20I0 2nd International Asia Conference on Informatics in Control, Automation and Robotics