209
Bowel Polyp Detection in Capsule Endoscopy Images
11.2 Color and Shape Feature Analysis
A polyp is an abnormal growth of tissue protruding from the mucous
membrane. Polyps are commonly found in the intestine, stomach, and so
on. Intestinal polyps grow out of the lining of the small and large bowels,
and they come in a variety of shapes—round, droplets, and so on. They
also exhibit different colors. Figure 11.3 shows a few normal CE images,
and Figure 11.4 shows some CE images with different polyps that vary in
color, size, and shape (refer to color originals in Li and Meng 2009e). From
these illustrations, it can be noticed that polyps show some differences
in color compared to normal CE images. Moreover, polyps demonstrate
some specific shape features. These interesting properties motivated us
to investigate the combination of color and shape features to discriminate
normal CE images from polyp CE images. We proposed a novel color feature based on a histogram of the chromaticity channel in hue, saturation,
intensity (HSI) color space and then integrated it with a traditional but
powerful shape feature, that is, Zernike moments, for CE images.
(a)
(b)
(c)
(d)
FIGURE 11.3
Representative normal intestinal CE images.