Error when creating noise map

Hello everyone!

I just started using mrtrix. I would like to create a noise map using dwidenoise but when I type the command:

dwidenoise -noise level input.nii.gz noise_map.nii.gz

I get this error:

dwidenoise: [ERROR] unknown format for image “level” (no file extension specified)
dwidenoise: [ERROR] error creating image “level”

I imagine it’s a syntax error in the command… how can I fix it?

Hi @Manuela and welcome to the community!

You must specify an image type by adding a filetype suffix to level (e.g. .nii.gz or .mif).


@smeisler thank you very much! However I am bit surprised because I don’t find a documentation that explains this. For instance here dwidenoise — MRtrix 3.0 documentation I don’t find this information. Is this written somewhere ?

Hi @Manuela,

It is implied by the argument being “The output noise map”, as in the documentation. The error message is also pretty explicit.