Dear SPM people,
after reading of two papers by Thevenaz et al I have two questions about
spline interpolation:
- Our preprocessing steps include realignment without reslicing and
b-spline interpolation after normalisation as recommended by John
Ashburner. Thevenaz favours in his comparison of interpolation methods
clearly b-spline for several reasons. But he restricts his discussion to
data "regularely sampled on a Cartesian grid". After the normalisation
(before resampling) the images are warped by DCTs and not regularly
sampled. Q: Is it justified to use b-spline interpolation on warped data?
- Discussing image artifacts Thevenaz reports ringing artifacts especially
with high-quality interpolation because their synthesis functions are
oscillating. How does the degree of b-splines affects such a ringing?
Best wishes from Giessen
Bertram
--
Dr. Bertram Walter
Bender Institute of Neuroimaging
University of Giessen
Otto Behaghel Str. 10F
D 35394 Giessen
Germany
Phone +49 (641) 9926307
or +49 (641) 9926081 (Secretary)
Fax +49 (641) 9926309
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