Biomedical Engineering Reference
In-Depth Information
Figure 9.
(a) Population,
p
pop
c,i
(
x, y
)
, and virtual operator,
p
VO
c,i
(
x, y
)
, distributions for
the image shown in Figure 1. The larger ellipses represent the spatial extent of
p
pop
c,i
(
x, y
)
,
whereas the smaller ones represent
p
VO
c,i
(
x, y
)
. (b) Closeup of control point 1. (c) Closeup
view of control point 2. Reprinted with permission from the AAPM.
above, in these two areas the ultrasound reflection from the prostate boundary is
weak, resulting in low boundary contrast and variable selection of the location of
the prostate boundary.
3.4. Example Application of Virtual Operators
We have used virtual operators to evaluate the sensitivity of our algorithms to
the choice of parameters and also to optimize the choice of their values [38]. In this
section, we present an example of evaluating the sensitivity of our segmentation
algorithm to the parameter
σ
in Eq. (3a).
