Using the color set back-projection algorithm in retrieval and evaluation of endoscopic images from patients with peptic ulcer

This paper presents an original method of implementation of the color set back-projection algorithm, algorithm that allows the automated detection of the color regions from a color medical image. For the implementation of the color set back-projection algorithm, the image is transformed from RGB color space to HSV color space and quantized at 166 colors. At the end of this process, the color set of the image is obtained and used in color region detection. The software was tested on a gastroenterologic imagistic database that included 202 patients with peptic ulcer disease. One endoscopic image was taken at inclusion and another two at visit 1 and 2 for each patient, in order to evaluate the cicatrisation process under treatment. It was compared the percentage of correct diagnosis attended by using the classic observational method with the results obtained with the computer-based one in terms of reliability and reproducibility of this method. There were evaluated the advantages of using a computer-based retrieval system in terms of reducing the time spent on this operation. The inter-observer disagreement between human observer and the computer software was significantly low and the speed of the computerized method was higher, proving benefits in terms of time and cost efficiency.