[Neuroimaging] [DiPy] Registration problem integer image arrays

Bene Wiestler b.wiestler at tum.de
Thu May 3 03:04:57 EDT 2018


Hi,

I have a problem with the dipy image registration workflow:
I want to register two anatomical images using linear methods 
(c_of_mass, translation, rigid). One file is a uint16 data type, the 
other is saved as a float, however essentially also only contains 
integer. When I load these files with nibabel and convert the data 
arrays to int16 (both with the .astype(np-int16) methods and with 
numpy.asarray), registration (even c_of_mass) always yields an empty 
transformed moving image (i.e. just containing 0s). However, when I save 
the files using the converted int16 data arrays and open them in e.g. 
ITK-Snap, they look fine.
When I convert both files to float32, registration works, but is slow.
Further, when I run your example script for affine registration with the 
files provided there (Stanford; syn; both int16), it works fine for 
these files.
Has anybody any idea what might be a solution other than just float32?

Thanks a lot!

Bene


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