[Insight-users] Fwd: Re: Writing filter output to a mesh

[Luis Ibanez]

Hi Gita,


Thanks for the clarification.


To what parameter, of what filter,
are you referring when you say :

                scale=0
(?)


It seems that we are missing a good description
of the problem that you are facing.


Would you mind to provide a better summary ?


     Thanks


        Luis


---------------
Gita Das wrote:
> Hi Luis,
> Please refer to my earlier e-mail regarding using the output of
> BinaryMask3DMeshSource as the input of DeformableMesh3DFilter. I saved
> the mesh data (mesh-to-stl) for both the filter outputs & they (e.g
> vertex -227.663 108 -75.75) are exactly the same for both. So, the
> positions haven't changed due to DeformableMesh3DFilter. However, to
> experiment when I used scale=0, all the vertex values for the deformed
> mesh was 0.
> Any help would be greatly appreciated.
> Kind regards,
> Gita  
> 
> 
> ------------------------------------------------------------------------
> 
> Subject:
> Re: [Insight-users] Writing filter output to a mesh
> From:
> Gita Das <Gita.Das at med.monash.edu.au>
> Date:
> Wed, 28 May 2008 15:28:46 +1000
> To:
> Luis Ibanez <luis.ibanez at kitware.com>
> 
> To:
> Luis Ibanez <luis.ibanez at kitware.com>
> 
> 
> Hallo Luis,
> 
> Thank you so much for your help.
> 
> I would like to adapt the mesh (o/p of BinaryMask3DMeshSource) using
> information from the raw scan. To do this I need to move each vertex
> along a direction normal to the mesh surface so that it is located on
> the maximum derivative in this direction. I could use the output of
> Marching cube and the raw image as two inputs of a DeformableMesh3DFilter.
> 
> I am using ParaView to check input ( o/p of BinaryMask3DMeshSource) and
> output (o/p of DeformableMesh3DFilter) meshes. 
> 
> How do I really compare them (with ParaView?) to see the effect of
> refinement? 
> Also, how do I check that the mesh is actually sub-voxel accurate? 
> Kind regards,
> Gita
>  
> 
> 
>>Richard, Gita,
>>
>>The output of the LevelSet segmentation filters is a gray scale image.
>>
>>If you take this image as input to the BinaryMask3DMeshSource, the
>>process for extracting the iso-surface will perform a linear
>>interpolation to locate the position of the surface in-between voxel
>>positions.
>>
>>The filter name is misleading. It makes you think that the input
>>must be a binary mask. In practice, any 8-bits grayscale image
>>should do fine as input.
>>
>>The Mesh that you will get at the output of the MeshSource will
>>have points located at sub-voxel positions.
>>
>>
>>If this doesn't work, then Plan B is to convert the level set
>>to a vtkImageData, and then use the vtkContourFilter.
>>
>>
>>Please let me know if you run into any problem.
>>
>>
>>   Thanks
>>
>>
>>      Luis
>>
>>
>>
>>---------------
>>Gita Das wrote:
>>
>>>Hi Luis,
>>>
>>>Thank you for your response.
>>>
>>>As mentioned in Richard's e-mail we need to get generate mesh 
>>
>>that have
>>
>>>vertexes positioned with sub-voxel accuracy. I was thinking if I 
>>
>>could> retrieve the points at the ZeroCrossingImageFilter that been 
>>used inside
>>
>>>GeodesicActiveContourFilter and then save it to a PointSet, and then
>>>generate a mesh....will that be what I want?
>>>
>>>I would greatly appreciate your suggestion/idea.
>>>Regards,
>>>Gita
>>>  
>>>
>>>
>>>
>>>>Hi Luis,
>>>>
>>>>Gita and I are trying to get at the internal, sub voxel precision,
>>>>mesh that is used (I believe) inside most of the level set tools,
>>>>rather than the version that has been converted back to voxel
>>>>precision. Any suggestions on where to start looking at how to 
>>
>>achieve>>this?
>>
>>>>Thanks
>>>>
>>>>On Sun, May 18, 2008 at 2:19 AM, Luis Ibanez 
>>>><luis.ibanez at kitware.com> wrote:
>>>>
>>>>
>>>>>Hi Gita,
>>>>>
>>>>>You can take the LevelSet that is produced as output of the
>>>>>Geodesic Active Contours filter, and pass it as input to the
>>>>>BinaryMask3DMeshSource filter in order to produce a Mesh as
>>>>>the output.
>>>>>
>>>>>If the purpose is to perform visualization you could also
>>>>>take the level set, convert it to a vtkImageData and then
>>>>>use the vtkContourFilter.
>>>>>
>>>>>
>>>>> Regards,
>>>>>
>>>>>
>>>>>
>>>>>      Luis
>>>>>
>>>>>
>>>>>------------------
>>>>>Gita Das wrote:
>>>>>
>>>>>
>>>>>>Dear Luis,
>>>>>>I need to write the output of a Geodesic Active Contour Image 
>>>>
>>>>Filter to
>>>>
>>>>
>>>>>>a mesh instead of an output image. I would appreciate any 
>>>>
>>>>help/suggestion.>> Kind regards,
>>>>
>>>>
>>>>>>Gita Das
>>>>>>Monash University
>>>>>>Australia
>>>>>>
>>>>>>
>>>>>
>>>>>_______________________________________________
>>>>>Insight-users mailing list
>>>>>Insight-users at itk.org
>>>>>http://www.itk.org/mailman/listinfo/insight-users
>>>>>
>>>>