Visual analysis is required to perform many biological experiments, from counting yeast colonies to measuring the size and shape of individual cells or the intensity of fluorescently labeled proteins within them. This unit outlines the use of CellProfiler, a free, open-source image analysis tool that extracts quantitative information from biological images. It includes a step-by-step protocol for automated analysis of the number, color, and size of yeast colonies growing on agar plates, but the methods can be adapted to identify and measure any objects in images. The flexibility of the software allows users to tailor pipelines of adjustable modules to fit different biological experiments, to generate accurate measurements from dozens or even hundreds of thousands of images.
(c) 2008 by John Wiley & Sons, Inc.