> I have a question about .mat files of SPM2.
>
> I can read SPM99 style analyze files with SPM2, and they appear to be
> correct. However, when I process them in SPM2, the new files that it
> created are flipped. Why would SPM2 read and display the old files
> correctly and flip the new files that it created during processing?
>
> Looking into newly created .mat files, I can see matrices M and mat.
> Matrix M is identical to that of the original file, but matrix mat has
> the first row negated. If I understand it correctly, the files would
> not be flipped if matrices M and mat were identical. How and where does
> SPM2 calculate this mat matrix? What are the variables that affect it?
> (data from .hdr file, default values) Our defaults.analyze.flip is set
> to 0.
Check to make sure that there are no warning messages about
defaults.analyze.flip not being set. If you run functions without running
spm_defaults, then SPM doesn't know what value to assign to the flip. If
defaults.analyze.flip is not set, then spm_flip_analyze_images will issue a
warning and assume that it should be set to 1.
Best regards,
-John
|