Fig. 17:

Histograms of the displacement magnitudes in millimeters. These histograms were generated using 115 test volumes from the IXI dataset. The displacement magnitude is computed as $\sqrt{d_x^2+d_y^2+d_z^2}$, where $d_{\{x,y,z\}}$ denotes the displacement in x, y, and z directions. The median displacement magnitude is shown in the upper right corner of each plot. To provide fair comparisons, only models that produce dense displacements are shown here. VoxelMorph and CycleMorph are ConvNet-based models, whereas the other models are Transformer-based.