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ned as partitioning the image into the meaningful areas
using the existing (low level) information in the image and prior (high level)
information which can be obtained using a number of features of an object. The
human vision system aims to extract and use as much as possible information in the
image. The possible information includes the intensity, possible motion of the
object (in sequential images), spatial relations (interaction) as the existing infor-
mation, and the shape of the object which is learnt from the experience as the prior
information. The machine visual system cannot predict the prior information unless
it is supplemented. Hence, any prior cue can be speci
Segmentation can be de
ed beforehand to enhance the
segmentation or to obtain the desired segmentation. If the prior information of the
object is not given beforehand to the machine vision task, the segmentation method
may not give desired results due to noise, occlusion, and missing information in the
image.
One of the bone diseases, which is characterized by a reduction in bone mass, is
Osteoporosis. This disease results in an increased risk of fractures. Bone Mineral
Density (BMD) measurements and Fracture Analysis (FA) of the VBs should be
obtained to accurately diagnose the osteoporosis. To obtain these measurements and
analysis, VBs should be accurately segmented, which is our main objective in this
work.
Since BMD measurements and fracture analysis are restricted to the vertebral
bodies, segmentation approaches should successfully isolate VB from processes,
which constitute spine bone as shown in Fig.
1
. However, due to region inhomo-
geneities existing in CT images, isolating a VB form its background is not an easy
task as shown in Fig.
2
. To overcome these inhomogeneities and accurately seg-
ment VBs, we use both shape and appearance information.
Fig. 1 Vertebral Body: A CT
slice of vertebral body
illustrates its regions: the VB
region (in blue color), which
is our region of interest to be
segmented. Spinal processes
and ribs, which should not be
included in the BMD
measurements, are shown
as well
