Deoxyribonucleic acid (DNA) is an important molecule which has a tendency to easily have damage. Etiology of many diseases like cancer, cardiovascular disease, and immune deficiency is asserted to be based on DNA damage. Comet assay is a reliable, cheap and easy method to specify whether DNA has damage or not. The fact that the number of developing software applications on demand increases day by day comes into prominence of obtaining quick and accurate results in medicine field. In this study, a software application is developed which single comet objects on comet assay images are identified to perform analysis, calculation of comet parameters and decision regarding whether DNA has damage or not. Comet images are converted to red channel images, the randomized automated thresholding method is applied on red channel images and connected component labeling obtains each single comet object. This paper mainly focuses on specifications and mathematical model of the thresholding method.