Robust autofocusing in microscopy using particle swarm optimization

An autofocusing procedure is routinely performed under a microscope to maintain micro-objects within the depth of field of an objective lens. The aim of this procedure is to search for an optimum image with sharp edges of the outlines and features of the micro-objects by tuning the position of the objective lens. This paper describes a new robust autofocusing search algorithm based on bare-bones particle swarm optimization (BBPSO). The proposed search algorithm has been validated experimentally using sharpness analysis based on image variance.