Sct_register_multimodal: -owarpinv does not work?

SCT
#1

Dear all,

I am trying to use sct_register_multimodal to generate the transformation/warp from PAM50 to MT and inversely. It works fine for the forward (-owarp), meaning the warp file is generated; but not for the (-owarpinv) for which no file is generated.
Attached is the log file.
log_file (20.4 KB)

Did I miss an option to be enable to get the inverse warp?
Also, I was wondering: is this transformation symmetric (ie inverse(A) = B and forward(B) = A) ?

I am using SCT 5.4 on Ubuntu 20.04.1.

Best regards,
Malo

#2

Hi Malo,

When you specify a starting forward transformation with -initwarp, you also need to specify the backward transformation with -initwarpinv. See the log file line 26:

WARNING: No initial inverse warping field was specified, therefore the registration will be src->dest only, and the inverse warping field will NOT be generated.

Also, I was wondering: is this transformation symmetric (ie inverse(A) = B and forward(B) = A) ?

Yes, both centermass and bsplinesyn are bijective transformations.

#3

OK, I guess I missed this line in the log. I added the initial inverse warping and now it works!
Thank you Julien for your quick answers.

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