nifti-phantom demo data set

Synthetic MRI simulation data for demonstrating the NIfTI phantom file format. mrx-org/nifti-phantoms: NIfTI simulation phantom file format specification and reference implementation Contains three phantoms, generated by code (see here) subj42-3T.json - a "subject" containing the typical brain phantom structur (synthetic data is just a ring) shapes.json - three tissues are three different geometrical shapes shapes_resliced.json - same as shapes.json but with different resolution and affine to test reslicing capabilites