[Insight-users] ITK measurement units

[Karthik Krishnan]

Michael Halle wrote:

> Luis Ibanez wrote:
>
>>
>> Hi Kevin,
>>
>> The units will be the same as the ones used for the pixel spacing
>> in the input images.
>>
>> If your images were using spacing in millimeters, then the units
>> of the deformation field computed by the deformable registration
>> will also be in millimeters.
>>
>> If your images were using spacing in microns, then the units
>> of the deformation field computed by the deformable registration
>> will also be in microns.
>
>
> Related to this topic, has there ever been any discussion about 
> retaining measure and unit names for different data dimensions through 
> standardized fields in the metadata dictionary?
>
> I'd suggest two fields for each dimension: the first describing the 
> quantity being measured, the second the unit of measure.  For example:
>
> "spatial extent" "mm"
> "time" "second"
>
> In the simplest case, ITK wouldn't interpret these strings at all, 
> just store them in a standard field for the pipeline to use if it wanted.


The metadata dictionary as it is now, isn't propagated through the 
pipeline at all. Something that it might be worthwhile having the 
itk::ProcessObject do in future.

Thanks
regards
-karthik