An Optical Colon Contour Tracking System for Robot-aided Colonoscopy: Localization of a Balloon in an Image using the Hough-transform

Abstract

During colonoscopy there is a risk that the intestinal wall may be injured or may pain occur by the insertion of an endoscope. Surgery through endoscopes must be learned by physicians through extensive training. To simplify the insertion of endoscopes, research is being carried out on robotic - aided systems. Here, a sensor is needed to detect the contour of the intestine in order to enable an injury - free and painless insertion of the endoscope. In this paper a tube - balloon is designed for a gentle contour tracking of the intestinal anatomy. This is inserted through the working channel of the endoscope and placed in the intestinal lumen in front of the endoscope's head in the field of view of the camera. A Matlab - algorithm is used to detect the balloon in each image. The balloon appears as a two - dimensional circle, which can be detected using a Hough -Transformation. The displacement of balloon after touching the intestine wall is calculated as a vector between the circle's center and the image center. This ensures that the robot - aided endoscope can follow the intestinal contour.