  Wireless capsule endoscopy (WCE) is a process in which a patient swallows a
camera-embedded pill-shaped device that passes through the gastrointestinal
(GI) tract, captures and transmits images to an external receiver. WCE devices
are considered as a replacement of conventional endoscopy methods which are
usually painful and distressful for the patients. WCE devices produce over
60,000 images typically during their course of operation inside the GI tract.
These images need to be examined by expert physicians who attempt to identify
frames that contain inflammation / disease. It can be hectic for a physician to
go through such a large number of frames, hence computer-aided detection
methods are considered an efficient alternative. Various anomalies can take
place in the GI tract of a human being but the most important and common ones
and the aim of this survey are ulcers, polyps, and tumors. In this paper, we
have presented a survey of contemporary computer-aided detection methods that
take WCE images as input and classify those images in a diseased/abnormal or
disease-free/ normal image. We have considered methods that detect tumors,
polyps and ulcers, as these three diseases lie in the same category.
Furthermore bleeding inside the GI tract may be the symptoms of these diseases;
so an attempt is also made to enlighten the research work done for bleeding
detection inside WCE. Several studies have been included with in-depth detail
of their methodologies, findings, and conclusions. Also, we have attempted to
classify these methods based on their technical aspects. This paper also
includes a potential proposal for joint classification of aforementioned three
diseases.
