Biomedical Engineering Reference
In-Depth Information
Figure 7.
2D breast leision characterization system.
equation, since the rate of change of the length of the curve is a function of
∂C/∂t
.
Finally, the above equations can be written in terms of differential geometry using
divergence as
∇
∂ψ
∂t
=
∇·
ψ
|∇
ψ
|
,
(10)
|∇
ψ
|
where geometrical properties such as normal curvature
N
and mean curvature
H
are given as
∇
.
N
=
∇
ψ
ψ
and
H
=
∇·
(11)
|∇
ψ
|
|∇
ψ
|
In conclusion, the advantage of the level set approach is that there are no
significant differences in following fronts in three space dimensions. By simply
extending the array structures and gradients operators, propagating surfaces are
easily handled (see Sethian et al. [20]).
5.
2D CONTINUOUS STRAIN MODE SYSTEM
In this Section we describe an elasticity analysis technique based on the level
set method (see Moon et al. [22]). In this CAD system, level set segmentation
plays the major role in influencing the results of elasticity analysis. Using the
proposed preprocessing procedures (including anisotropic diffusion filtering), we
employ the stick method to help remove noise from ultrasound images and im-
prove segmentation performance, Acquisition of ultrasonic data is described in
Section 3.2. The system flowchart is shown in Figure 7.
5.1. Preprocessors for Ultrasound Images
For medical images, there are some fundamental requirements regarding noise
filtering methods that should be noted. First, it is crucial to not lose such important
