Biomedical Engineering Reference
In-Depth Information
Fig. 9
Representation of the filtered backprojection method. Each view is first filtered or
convoluted with an appropriate function. (
a
) Represents the process for only three views; (
b
)the
same process for a large number of views (Adapted from [
16
])
Fig. 10
Overview of iterative
methods for image
reconstruction
Estimated
image
Expected
projections
()
Projection
(
)
ˆ
(
X
(
n
)
)
ˆ
n
P
Update
Comparision
Error in
image
Error in
projections
(ε
p
)
Backprojection
(ε
i
)
Image space
Projection space
X
.n/
, which is projected
1. The process starts with an estimate initial image,
P
.n/
, which would be the expected projections
obtaining the set of projections,
if
X
.n/
were the true picture.
2. The projections
P
.n/
are then compared with the measured projections
P
,
obtaining a set of errors,
"
p
, in the space of projections.
