Hi there FSL users,
I'm upsampling time series data from 2.5mm to 2.0mm isotropic, using cubic interpolation. The upsampled data seemed fine, but when I look at metrics like temporal stdev, I see some kind of grid-like artifact. I tried sinc interpolation (basically the same as spline) and trilinear (MUCH bigger artifact).
I'm attaching some representative screenshots. For me, the more subtle artifact in the sinc+spline images is easier to see if you start with the trilinear.
