Information Technology Reference
In-Depth Information
Fig. 1 A schematic view of the graphical model based representation of a spinal structure
h
i
; h
i
;
h
i
; h
i
g
set X
i
¼f
to V
i
to describe the positions, sizes and
orientations of the vertebral body and the upper/lower intervertebral discs of Vi
i
as
shown in Fig.
2
. E
x
i
;
y
i
;
r
i
;
h
i
;
a
i
ðh
i
Þ;
e
i
;
j
;
ne a connection matrix of
the graph G. On this graphical model, the observation model of a single component
V
i
is de
¼
i
;
j
¼
0
;
1
;
2
; ...;
N
1de
ned as p I
ð
j
X
i
Þ;
i
¼
0
;
1
; ...;
N
1 and the potential among neighboring
components V
i
and V
j
with e
i
;
j
¼
ned as p X
i
;
;
;
¼
;
; ...;
;
1isde
X
j
i
j
0
1
N
1
e
i
;
j
¼
1. From a probabilistic point of view, p I
j
X
i
ð
Þ
represents the probability that
