ABSTRACT
Recent years have witnessed some development on automatic inspection of WCE images (see Li and Meng 2012, Figueiredo et al. 2013, Coimbra and Cunha 2006, Alexandre et al. 2008, Liedlgruber and Uhl 2011, Hwang and Celebi 2010, Karargyris and Bourbakis 2010). In this article, we focus on colonic polyp detection in WCE images. In particular, the images are acquired by the PillCam Colon capsule, produced by Given Imaging. This device, released first in 2006 and subsequently improved in 2009, was specifically developed for colon visualization and also with the purpose of screening for colorectal cancer, as an alternative to conventional colonoscopy. The polyps to be detected in the images are characterized by physicians according to human perception of their distinctive shapes, color and texture on these geometric objects. In effect,
1 INTRODUCTION
Colon cancer is one of the leading causes of cancer death worldwide. A colon polyp is a growth on the surface of the colon (also known as the large intestine). Some colon polyps are benign, which means they are not cancer. But some types of polyps may already be cancer or can become cancer. For this reason it is important to identify and remove these polyps to prevent colon cancer developing. Wireless capsule endoscopy (WCE) is a new imaging technique that allows the visualization of the entire gastrointestinal (GI) tract, without pain and sedation. It was first invented by Given Imaging, Yoqneam, Israel in 2000 (Idan et al. 2000) and the first device got approval from the US food and drug administration (FDA) in 2001 During the procedure, patients swallow a multivitamin size capsule, consisting of a miniaturized camera, a light source and a wireless circuit for the acquisition and transmission of signals. As the capsule moves through the GI tract, due to peristalsis, images are wirelessly transmitted to a portable recording device. The stored images are transferred to a computer workstation, where physicians can view the images and analyze the potential sources of different
according to medical information, the geometry of colonic polyps can be classified essentially in two types: pedunculate polyps, which are mushroomlike structures attached by a thin stalk to the colon mucosa, and sessile polyps, which are like caps (mushroom structures with no stalk). Their color is in general red, reddish or rose, and their texture can be very similar to a human brain.
