CIPA 2003 XIX th International Symposium, 30 September-04 October, 2003, Antalya, Turkey
Definition 1 Let the extracted color values for a given par
ticle be C = {co, Ci, ..cm~\] for an image sequence S =
../jV—l }• The color of the particle for this sequence
is photoconsistent if
1. There exists at least two images in S in which the par
ticle is not occluded.
2. The particle is not on the background in any of the
images in S.
3. C a < © where C a is the standard deviation of inten
sity values of the colors in C.
Overall appearance reconstruction process is described in
Algorithm 2: by projecting the particle on the source im
ages, a set of candidate colors is extracted. If the recon
structed set is photoconsistent then the color of the particle
is selected as the median of this set. If a particle is occluded
in all of the images or a photoconsistent color cannot be
extracted from the sequence, there occurs regions whose
appearance cannot be recovered on the model. The colors
of the particles in these regions are interpolated using the
colors of the adjacent particles.
Algorithm 2 Recovering the color of a particle,
reset the candidate color set of the particle to empty set
for all images in the sequence do
if particle is visible in the image then
project particle on the image
insert the extracted color in C
end if
end for
if C is photoconsistent then
set the color of the particle to the median of C
else
set the color of the particle to the color of the nearest
particle whose color is consistent.
end if
4 EXPERIMENTAL RESULTS
The experiments are performed on a personal computer
with 512 MB of RAM, Intel PHI 800Hz CPU and 32MB
frame buffer. The images are captured with a 2/3” Color
Progressive scan CCD camera at a resolution of 1294x1030.
While rendering the final model, texture mapping is per
formed using the routines provided by OpenGL.
As shown in Figure 6, the algorithms are successful in re
moving the highlights which possibly occur at the image
acquisition step. Reconstruction results given in Figure 7
show that objects which have holes and arbitrary shapes
can also be modeled by this method. Concavities can suc-
cesfully be detected and carved in our method as shown in
Figure 8 and Figure 9.
Figure 6: (a) Sample images, (b) sample reconstructions
for the “box” object.
images
Figure 7: Sample reconstructions for a “cup”object and a
small artifact, “toy” object.
models
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