This parameters (--dfout and --jacout) in topup

What are the use of this parameters (–dfout and --jacout) in topup, please? I didn’t find anything about it on the official website or in the help.


--dfout: warp field

--jacout : : output Jacobian image (of the TOPUP warp field)

Additionally you can also get:

--rbmout : MotionMatrix

I found this information in this code (line 299)

By the way, for FSL specific question, you could also ask the FSL forum when you can get direct answers from the FSL developers:

Thanks for the guidance, what is the difference among --fout, --dfout and --jacout?

My general understanding is that the fieldmap is the estimation of the B0 field deviation (usually in Hertz), the warping field is the deformation field that needs to be applied to the data depending on the fieldmap and the data acquisition parameters. The Jacobian modulation serves to adjust the intensities of voxels that have been stretched or compressed.

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I understand, thanks for the guidance.