[Insight-users] Need help with PermuteAxesImageFilter

[Hans Johnson]

Hello All,

The MetaDataDictionary is for "important domain specific additional
information" that is not generic enough to be a part of ITK proper member
functions and concepts.

Dealing with orientation with the MetaDataDictionary was a stopgap measure
quickly put into ITK 2 years before the concept of object Direction was
formally added.  The MetaDataDictionary orientation hacks allowed ITK to
deal with orientation in a very small subset of circumstances.  It is
inconsistently used at best.

Now that Direction is a formal concept in ITK, and has had a lot of thought
and effort in to implementing it, and it is deployed uniformly and
consistently throughout itk, I would recommend with the strongest
encouragement that you do not depend on the MetaDataDictionary tags.

I say this as the original implementer and voice behind the original
MetaDataDictionary and orientation implementation.  The MetaDataDictionary
tags are to be trusted ONLY in how each of the end-users applications
determines how to use it.

In particular, this week I have been trying to use programs for several
years ago on new datasets, and almost every application that used
MetaDataDictionary failed on the new data types (nifti does not set the
MetaDataDictionary orientation flags, and Analyze only has a few supported
orientations).  Fixing the old programs was really easy, just replace the
MetaDataDictionary Expose/Encapsulate of itk::SpatialOrientation with calls
to GetDirection and SetDirection, and all issues went away regardless of the
storage format of the data.

Regards,
Hans



On 8/26/06 9:25 AM, "Luis Ibanez" <luis.ibanez at kitware.com> wrote:

> Hi Martin,
> 
> What exactly is the error that you are getting ?
> 
> Please let us know,
> 
> 
>     Thanks
> 
> 
>        Luis
> 
> 
> ---------------
> MX wrote:
>> 
>> 
>> Hi Luis,
>> 
>> I'm still having problems with the MetaDataDictionary,
>> i now changed the header tags according to the permutation order. I checked
>> the header afterwards and it seems that the values in the header are now
>> permuted too.
>> But I'm still getting the same error. Are there any more tags that have
>> to be changed?
>> 
>> Thx,
>> Martin
>> 
>> 
>> 
> 
> 
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