Using imregister for 3D images of different size

Hello,

I have 2 3D volume images (MRI) with different number of slices. One set has 47 and the other 50 layers. Would imregister work in this case? How can I see the results and know how well it works since I don't know which 2 slices are lined up? Thank you for your help.

[Sean de Wolski]

Are the slices the same thickness?

Answer 1

[Sean de Wolski]

The inputs don't need to be the same size but it can help the optimizer if they are.

[Bahar]

Thank you. Also I know how to get the transformation matrix, but as I understand the elements of the matrix are the products of translation, rotation, scaling and shear transformations. I need to know which 2 slices line up, and for that I need the elements corresponding to translation only. How can I find that?

[Sean de Wolski]

These are the transformation matrix of bottom row until end-1

T =
   1     2     7     0
   0     1     0     0
   5     0     1     0
   2    -4     1     1

Here the [2, -4, 1] are the translations in row/col/page

Generalized:

translation = T(end,1:end-1)

[Bahar]

Thanks Sean