On Path Length Estimation for Wireless Capsule Endoscopy

Wireless capsule endoscopy (WCE) is a non-invasive technology used for inspection of the gastrointestinal tract. Localization of the capsule is a vital part of the system enabling physicians to identify the position of anomalies. Due to intestinal motility, the positions of the intestines will change significantly within the abdominal cavity over time. However, the distance from one position to another within the intestines changes much less. In this paper a method for calculating the pathlength travelled by a WCE is proposed. The method is based on Kalman- and particle filters and is simulated using a model that approximately replicates the movement through the small intestine. The travelled distance was estimated to an accuracy within a few millimeters.