High-quality two-stage resampling for 3-D volumes in medical imaging

This paper introduces a simple method of two-stage resampling where Fourier-domain up-sampling is followed by traditional resampling. Practical aspects as well as efficient implementation techniques are considered. A new version of pruned FFT algorithms to calculate the up-sampling stage is also introduced. The suggested two-stage resampling method provides very high-quality results exceeding those of the previous algorithms. It excels with higher dimensional datasets due to its ability to employ small-support kernels. The applied FFT algorithms make the method most efficient with dataset sizes of powers of two. These reasons and the importance of minimal resampling artifacts make the suggested method especially suitable for 3-D volumes in medical imaging. Furthermore, for repeated uses, only the second stage is recalculated allowing an increase in performance for motion correction applications in functional magnetic resonance imaging (fMRI), for example.