Dwidenoise create negative values




I use dwidenoise and I found a issue. Before running the denoising, I checked my dwi and the min was 0. But after the denoising negative values appears.

Is it an issue or it’s normal ?


I don’t think there’s anything suspicious here. There’s nothing in dwidenoise that would explicitly prevent negative values, and I think it’s a common finding (here’s at least one post that mentions this). There’s other operations that can also introduce this, including anything that involves cubic interpolation (which I think happens as part of dwipreproc). It shouldn’t cause issues with anything else, I don’t think…(?)