Content-based autofocusing in automated microscopy.

Autofucusing is the fundamental step when it comes to image acquistion and analysis with automated microscopy devices. Despite all efforts that have been put into developing a reliable autofocus system, recent methods still lack robustness towards fifferent microscope modes and distracting artefacts. This paper presents a novel automated focusing approach that is generally applicable to different microscope modes (bright-field, phase contrast, Differential Interference Contrast (DIC) and fluorescence microscopy). The main innovation consists in a Content-based focus search that makes use of a priori knowledge about the observed objects by employing local object features and Boosted Learning. Hence, this method turns away from common autofocus approaches that apply solely whole image frequency measurements to obrein the focus plane. Thus, it is possible to exclude artefacts from being brought into focus calculatin as well as locating the in-focus layer of specific microscopic objects