[Insight-users] Segmentation -> Spatial objects

[Dan Mueller]

Hi David,

> Now all I need is to know how  to go from polyline path to linespatialobject.
> What is the process?

create LineSpatialObject instance
foreach point in PolyLineParametricPath
   Transform to physical space (if required)
   Get the point list from the LineSpatialObject instance
   Add point to list

Regards, Dan

2008/8/8 David Dubois <dubois at enst.fr>:
> Hi,
>
> Thank you! This is getting me somewhere.  Now all I need is to know how
> to go from polyline path to linespatialobject.  What is the process?
>
> On a side note: Why isn't it possible to go from segmentation to spatial
> object directly?  David Marr's vision concepts point in that direction
> and it would be great for further analysis.
>
> DD
>
>
> Dan Mueller wrote:
>> Hi David,
>>
>> You are correct: there are no filters (at least none that I know of)
>> which explicitly create SpatialObjects. However, if you want to deal
>> with SpatialObjects, it should be trivial to create them using the
>> output of your specific filters. For example: say you are using a
>> filter which extracts a PolylineParametricPath defining a road, then
>> you can easily create a LineSpatialObject from the path.
>>
>> I guess it comes back to your original question: so what's the point
>> of SpatialObjects? From my understanding, there are three main uses
>> for spatial objects:
>>    1. Input/output: MetaIO supports reading and writing SpatialObjects
>>    2. Rendering as a scene graph: see http://www.vtk.org/Wiki/SOViewer
>>    3. Registration: see Code/Algorithms/itkImageToSpatialObjectMetric.h
>>
>> Hope this helps.
>>
>> Regards, Dan
>>
>> 2008/8/8 David Dubois <dubois at enst.fr>:
>>
>>> Hi Dan,
>>>
>>> I'm trying to extract lines and rectangular shapes from a 2d satellite
>>> image.  I'm using ITK from the Orfeo Toolbox (OTB) which is a extension
>>> of ITK specialized in satellite images.
>>>
>>> I did not see any filter that states it extracts spatial objects from
>>> images.
>>>
>>> Thank you for your help,
>>>
>>> DD
>>>
>>>
>>> Dan Mueller wrote:
>>>
>>>> Hi David,
>>>>
>>>> What spatial object type did you have in mind?
>>>>
>>>> ITK is capable of extracting meshes, contours, paths, tubes, and more.
>>>> However, these methods are highly application dependant. Please
>>>> provide more information regarding your exact situation. For example:
>>>> what dimension of images are you using: 2D, 3D, 4D? What type of
>>>> image: CT, MR, PET, satellite? What type of object are you trying to
>>>> segment: liver tumor, coronary artery, road?
>>>>
>>>> Cheers, Dan
>>>>
>>>> 2008/8/7 David Dubois <dubois at enst.fr>:
>>>>
>>>>
>>>>> Hi,
>>>>>
>>>>> I was wondering if there was a way to go from image to spatial objects
>>>>> using itk's various segmentation filters.  Like maybe a Label to Spatial
>>>>> Object king of filter.  I searched for this in the documentation without
>>>>> success.  I really dont see the use of spatial objects if you always
>>>>> have to define them manually.
>>>>>
>>>>> Thank you,
>>>>>
>>>>> DD
>>>>> _______________________________________________
>>>>> Insight-users mailing list
>>>>> Insight-users at itk.org
>>>>> http://www.itk.org/mailman/listinfo/insight-users
>>>>>
>>>>>
>>>>>
>>>>
>>>
>>
>>
>
>