[Paraview] Feature Request: vtkImageResample

Bryn Lloyd blloyd at vision.ee.ethz.ch
Fri Jan 30 10:56:07 EST 2009


Hi again,

It seems the vtkImageResample filter (and it's parent vtkImageReslice 
probably too) does not give the output array a name (unless no 
resampling is done).

This would seem to be a bug. However, I couldn't follow the code in 
vtkImageReslice to see where the name could be set or what the problem is.

Cheers
Bryn







Bryn Lloyd wrote:
> Hi,
> 
> I have tried it in a similar way with no success.
> 
> 
> It works though using following Set-methods:
> 
> //---------------------------------------------------------------------------- 
> 
> void vtkImageResample2::SetOutputSpacing(double v[3])
> {
>   this->SetOutputSpacing(v[0],v[1],v[2]);
> }
> 
> //---------------------------------------------------------------------------- 
> 
> void vtkImageResample2::SetOutputSpacing(double v0,double v1,double v2)
> {
>   this->SetAxisOutputSpacing(0,v0);
>   this->SetAxisOutputSpacing(1,v1);
>   this->SetAxisOutputSpacing(2,v2);
> }
> 
> 
> 
> With standard xml description:
> 
>       <DoubleVectorProperty
>          name="OutputSpacing"
>          command="SetOutputSpacing"
>          number_of_elements="3"
>          default_values="0 0 0" >
>       </DoubleVectorProperty>
> 
> 
> 
> I have place the code here:
> 
> http://www.vision.ee.ethz.ch/~blloyd/vtkImageResample2/
> 
> 
> 
> This seems to work (extent is changed say for MagnifactionFactos="0.5 
> 0.5 1.0"). But the image data becomes invisible. I think it converts the 
> PointData->Arrays to some other form, e.g. image scalars or something, 
> which paraview doesn't display.
> 
> 
> --Bryn
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Jérôme wrote:
>> Hi,
>>
>> I tried to do what you talked about, because I need isotropic volumes
>> for a number of algorithms. I think it is the same for you, right?
>>
>> I wrote an xml file that you can load in the plugin manager menu,
>> according to this wiki page:
>>    http://paraview.org/Wiki/Plugin_HowTo#Enabling_a_filter_in_VTK
>>
>> The problem is that the VTK filter seems not to be paraview-compliant:
>> it didn't work, but unfortunately I didn't have time to describe the
>> bugs. I joint the xml file, so that you can try and please tell me if
>> it works for you -then I may guess it is because of my settings...-.
>>
>> In a nutshell, here are my problems for a volume of spacing 0.5x0.5x1
>> that I want to be 0.5x0.5x0.5 ie magnification factor = 0.5 on axis z
>> (= 2)
>> - The filter updates, but the extent does not change in the output
>> - When representation of input is 'Slice', the output dimensionality 
>> is 2 !!!
>>
>> I hope someone could find the mistake, wherever it comes (my xml,
>> paraview, or VTK)
>>
>> I also write a Cxx class that inherites from vtkImageResample and
>> computes automatically the magnification factor depending on a
>> user-chosen reference axis (in my example, x or y). Today, I use an
>> independent executable that converts an input mhd file into an
>> isotropic volume, and then I open it in paraview. I would be glad if
>> this step is part of a paraview pipeline, but my inherited class has
>> the same behaviour than vtkImageResample (and I think that when I
>> tried with the parent class vtkImageReslice, the same problem
>> occured...).
>>
>> Jerome
>>
>> 2009/1/30 Bryn Lloyd <blloyd at vision.ee.ethz.ch>:
>>> Dear VTK Developers
>>>
>>>
>>> I would like to use the vtkResampleImage class in Paraview (plugin). For
>>> this purpose it would be helpful if in addition to the methods
>>>
>>> SetAxisMagnificationFactor (int axis, double factor)
>>> SetAxisOutputSpacing (int axis, double spacing)
>>>
>>>
>>> which are valid for axis 0,1 and 2, following new functions could be 
>>> added:
>>>
>>> SetAxisMagnificationFactor (double, double, double)
>>> SetAxisOutputSpacing (double, double, double)
>>>
>>>
>>> i.e. taking values for all three axis directions simultaneously.
>>>
>>>
>>> Could this be done?
>>>
>>>
>>> Thanks in advance!
>>>
>>> Bryn
>>>
>>>
>>>
>>>
>>> -- 
>>> -------------------------------------------------
>>> Bryn Lloyd
>>> Computer Vision Laboratory
>>> ETH Zürich, Sternwartstrasse 7
>>> CH - 8092 Zürich, Switzerland
>>> Tel: +41 44 63 26668
>>> Fax: +41 44 63 21199
>>> -------------------------------------------------
>>> _______________________________________________
>>> ParaView mailing list
>>> ParaView at paraview.org
>>> http://www.paraview.org/mailman/listinfo/paraview
>>>
> 
> 


-- 
-------------------------------------------------
Bryn Lloyd
Computer Vision Laboratory
ETH Zürich, Sternwartstrasse 7
CH - 8092 Zürich, Switzerland
Tel: +41 44 63 26668
Fax: +41 44 63 21199
-------------------------------------------------


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