[Rtk-users] Blurry reconstructions in ROOSTER

[erwinwalter11 at web.de]

Hi,

for my Master's thesis I am testing some implementations for a 4D
reconstruction of small mice set. For this I apply the rooster algorithm on
the full projection set with a discretised phase signal. To compare the
rooster reconstruction I also take a subset of the full set with
rtksubselect considering the phase signal and apply the regularized
conjugate gradient reconstruction algorithm on that subset of projections.
This way I get a 3D reconstruction for each phase respectively.



However with the same gamma_space=8e-6 (in regularized cg gammatv defined)
in the total variation step both in rooster and regularized conjugate
gradient and gamma_time equal to 0 in roosters algorithm, I do not get the
same results. The rooster reconstruction is much more blurried compared to
the regularized conjugate gradient reconstruction, which surprises me.
Shouldn't be both reconstructions nearly identical under same conditions?
Outer and inner loops (n_iter=30, tv_iter=10, cg_iter=4) are equally set.
The blurriness occurs only in respiratory phases with small amount of
projections (approx. 90)



For visualization I have added an example to the following link:
https://gigamove.rz.rwth-aachen.de/d/id/P42uxboh472jzV

The regularized conjugate gradient reconstruction is shown on both upper
images and the rooster reconstruction is shown on both lower images.



I appreciate any help or explanation.



Erwin

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