Graphics Reference
In-Depth Information
(a)
(b)
(c)
(d)
Figure 3.15. An example of graph-cut compositing. (a) Target image. (b) Source image, with user
strokes overlaid to indicate regions that must be included. (c) Graph-cut composite. (d) Region
labels used to form the composite (black pixels are from (a), white pixels are from (b)).
multi-image photomontage was suggested by Agarwala et al. [ 7 ], building off Kwatra
et al.'s framework.
The basic idea is to minimize a Gibbs energy of the form:
E
(
L
) =
E data
(
L
(
i
)) +
E smoothness
(
L
(
i
)
, L
(
j
))
(3.25)
i
V
(
i , j
) E
is the set of all adjacent pixels
(for example, 4-neighbors), and L is a labeling ; that is, an assignment in
Here,
V
is the set of pixels in the output image,
E
to
each pixel i . For the multi-image compositing problem, the user paints initial strokes
in each source image, signifying that pixels stroked in image S k must have label k in
the final composite. Natural forms of the two energy terms are:
{
1,
...
, K
}
0
if pixel i is stroked in S k
E data (
L
(
i
) =
k
) =
(3.26)
if pixel i is stroked in some image S j
=
S k
0
otherwise
E smoothness (
L
(
i
) =
k , L
(
j
) =
l
) =
S k (
i
)
S l (
i
) +
S k (
j
)
S l (
j
)
(3.27)
Search WWH ::




Custom Search