A self optimizing autofocusing scheme for microscope integrated visual inspection systems

This paper presents the development and implementation of a new, computer controlled microscope setup targeted to be used as the inspection unit of a microfactory system. The presented design has two degrees of freedom responsible for changing the magnification and focus level over the image respectively. Following the discussion on mechanical design and production, the couplings observed in experiments between magnification and focus levels are analyzed. Originating from the infeasibility of modeling the maximum sharpness point (i.e. maximum focus point) for any arbitrary object, a self optimizing controller structure is proposed that can work for any magnification level set by the user. The proposed controller structure is validated by experiments to restore the maximum focus point while the magnification level is arbitrarily set by the user.