Extended depth-of-focus algorithms in brightfield microscopy
Antonio G. Valdecasas, David Marshall, Jose M. Becerra
European Microscopy and Analysis September 2002: 15-17

Abstract
Extended depth of focus algorithms provide a set of very useful tools for obtaining in focus images of 3D objects and organisms. In this paper we review and compare three different classes of 2D extended depth of focus (EDF) algorithms: point, area and frequency domain based algorithms. The algorithms used are targeted and tested on biological microscopic objects. Basically a set of images are taken along the z axis by a digital imaging system attached to a microscope. The set covers all the object under study although a particular slice will have only portions of it in focus. Extended depth of focus algorithms are designed to scan through each slice in the set and build a single composite image with all the parts that are determined to be in focus.