[MINC-users] mincresample -like bug?

[Alex Zijdenbos]

! yes. You win the prize - the model volume indeed has irregular z-spacing
(and a bizarre series at that).

Should mincresample perhaps warn about this - or rather, what should the
correct behaviour be, if it is passed -like <irregular_spacing.mnc>?

-- A

On Mon, Mar 30, 2015 at 11:55 PM, Andrew Janke <a.janke at gmail.com> wrote:

> Do either of the files have irregular slice spacing in z ?
>
> a
> On 31/03/2015 2:30 PM, "Alex Zijdenbos" <zijdenbos at gmail.com> wrote:
>
> > I seem to have stumbled into something unusual: a failure of
> mincresample.
> >
> > [by the way, according to the GMail spell checker, the correct spelling
> of
> > 'mincresample' is 'creaminess'. duh.]
> >
> > Anyways, I have this:
> >
> > $ mincinfo in.mnc <https://www.dropbox.com/s/dwaz0ftbtefsfz7/in.mnc?dl=0
> >
> > model.mnc <https://www.dropbox.com/s/ic41vwursndyonj/model.mnc?dl=0>
> > file: in.mnc
> > image: unsigned short 0 to 65535
> > image dimensions: zspace yspace xspace
> >     dimension name         length         step        start
> >     --------------         ------         ----        -----
> >     zspace                     96            2     -321.707
> >     yspace                    134            2     -202.414
> >     xspace                    134            2     -132.414
> >
> >
> > file: model.mnc
> > image: signed__ short -32768 to 32767
> > image dimensions: zspace yspace xspace
> >     dimension name         length         step        start
> >     --------------         ------         ----        -----
> >     zspace                     94            2     -319.707
> >     yspace                    132            2     -200.414
> >     xspace                    132            2     -130.414
> >
> > Now I resample in.mnc like model.mnc:
> >
> > $ mincresample -like model.mnc in.mnc res.mnc
> > Transforming
> >
> >
> slices:..............................................................................................Done
> >
> > $ mincinfo res.mnc
> > file: res.mnc
> > image: unsigned short 0 to 65535
> > image dimensions: zspace yspace xspace
> >     dimension name         length         step        start
> >     --------------         ------         ----        -----
> >     zspace                     94            1            0
> >     yspace                    132            2     -200.414
> >     xspace                    132            2     -130.414
> >
> > Clearly, the zspace step and start of the resampled volume (yellow) don't
> > look at all like those of the -like volume (green). I suspect a numerical
> > precision issue causing the start/step calculation to go wrong, but I'm
> not
> > sure.
> >
> > In case anybody wants to play, you can get in.mnc and model.mnc from the
> > URLs in the first mincinfo call.
> >
> > -- A
> > _______________________________________________
> > MINC-users at bic.mni.mcgill.ca
> > http://www.bic.mni.mcgill.ca/mailman/listinfo/minc-users
> >
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>