Automatic antibiogram inhibition zone diameter determination through circular hough transform

The analysis of antibiotics towards a microorganism responsible of an illness is evaluated using the antibiogtam test. In the diffusion method which is the most popular implementation of this test, several paper disks, each one impregnated with a different antibiotic, are spread all over a agar plate which is diffused standard cultivation prepared from test microorganism. After some time, the reaction produced by the antibiotics against the microorganism appear as circular areas of different texture that have grown around the antibiotic disks. Currently, the evaluation and measurement of these areas, called Inhibition Zones, is carried out by human visual inspection via caliper in the laboratories. In this study, a new segmentation and analysis strategy to automatically measure the inhibition zone and disk diameters in antibiograms is presented. It is based on the application of circular Hough transform surrounded appropriate pre- and post-processing stages.