Hi,
medInria assumes your diffusion data to be made of two files :
- a single 4D image containing a series of diffusion weighted images
- a text file containing the list of gradients that were applied during the acquisition to obtain the images.
This text file is what you are missing. I would say you have two solutions to obtain it. If you are using a dicom converter to convert your data (like dcm2nii), it usually outputs a .bvec file when it converts diffusion data. If that is the case, you can directly use that .bvec file inside medInria. Otherwise, these gradients are usually available in the protocol you used at your MR scanner. You could then just stack them into a text file (just like the gradient7.txt in our example).
Hope this helps