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Computational and Mathematical Methods in Medicine
Volume 2017, Article ID 9813165, 13 pages
Research Article

Advanced Image Enhancement Method for Distant Vessels and Structures in Capsule Endoscopy

1Department of Computer Science, Norwegian University of Science and Technology, Trondheim, Norway
2Department of Gastroenterology, Innlandet Hospital Trust, 2819 Gjøvik, Norway

Correspondence should be addressed to Olivier Rukundo; moc.liamg@odnukuro

Received 10 July 2017; Revised 21 September 2017; Accepted 9 October 2017; Published 31 October 2017

Academic Editor: Kaan Yetilmezsoy

Copyright © 2017 Olivier Rukundo et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This paper proposes an advanced method for contrast enhancement of capsule endoscopic images, with the main objective to obtain sufficient information about the vessels and structures in more distant (or darker) parts of capsule endoscopic images. The proposed method (PM) combines two algorithms for the enhancement of darker and brighter areas of capsule endoscopic images, respectively. The half-unit weighted-bilinear algorithm (HWB) proposed in our previous work is used to enhance darker areas according to the darker map content of its HSV’s component . Enhancement of brighter areas is achieved thanks to the novel threshold weighted-bilinear algorithm (TWB) developed to avoid overexposure and enlargement of specular highlight spots while preserving the hue, in such areas. The TWB performs enhancement operations following a gradual increment of the brightness of the brighter map content of its HSV’s component . In other words, the TWB decreases its averaged weights as the intensity content of the component increases. Extensive experimental demonstrations were conducted, and, based on evaluation of the reference and PM enhanced images, a gastroenterologist (Ø.H.) concluded that the PM enhanced images were the best ones based on the information about the vessels, contrast in the images, and the view or visibility of the structures in more distant parts of the capsule endoscopy images.