Interpretation of Affine3D OpenSPIM registration values

Dear all,

I am performing some experiments on multi-view light-sheet images and have to register two consecutive views for this purpose and I am “prototyping” with the Sample Dataset of BigDataViewer.

I was able to successfully configure and run the SPIM registration routine as explained in: https://openspim.org/Registration

Now, I would like to make use of the output affine 3d model (4x4 matrix) given by:

m00 = 0.9998018295301213
m01 = 0.009272627385416399
m02 = 0.004172919116564366
m03 = -5.256384548370321
m10 = 0.0036720022497606633
m11 = 0.7134009881764888
m12 = 0.7302420518019044
m13 = 87.89635164768274
m20 = 0.00686465670785837
m21 = -0.6860665707913376
m22 = 0.7008292845649621
m23 = 370.05169220436886
m30 = 0
m31 = 0
m32 = 0
m33 = 1

Specifically, I would like to perform registration of the first (0º) and second view (45º) “by hands” with a dedicated script. However, it turns crucial to understand the units and meaning of the above mentioned values to perform the mapping.

Please consider that the first view corresponds to a 3D array of (1388,1040,91) [x,y,z] dimension, while the second view corresponds to a 3D array of dimensions (1388,1040,81).

I am particularly interested in understanding the parameter m23 given its high value when comparing with the Z dimension of the sequences. Is it scaled?

I would be glad to hear from you,

Thanks!