vbcmp

vbcmp compares two 3D or 4D files and tells you how they differ.

Here's the help for vbcmp:

VoxBo vbcmp (v1.8.5/Jun 14 2011)
summary: compare two or more vector, matrix, volume (3D) or series(4D)
usage:
  vbcmp [-m <mask>] <file> <file> [<file> ...]
flags:
  -m <mask>     restrict comparison to mask for 3D or 4D
  -h            show this help
  -v            show version
notes
  If you specify more than two files, you will get all pairwise
  comparisons.

Here's some sample output for 3D data:

[I] vbcmp: different voxels: 179923 of 184320 (98%)
[I] vbcmp: mean difference: 174.88974728
[I] vbcmp: max difference: 1361.00000000

And here's some sample output for 4D data:

[I] vbcmp: different voxels: 5732179 of 20643840 (28%)
[I] vbcmp: mean difference: 10.85106065
[I] vbcmp: max difference: 329.00000000
[I] vbcmp: 112 of 112 volumes differ