[Paraview] Feature Request: vtkImageResample

Tue Apr 28 15:47:36 EDT 2009

Hi!

Did someone try the attached file -in a former message of this thread- as a
ParaView plugin, and notice the problem I mentioned? It seems that Bryn
does... Anybody else? I feel so lonely...

Thanks!

Jerome

2009/4/21 Jérôme <jerome.velut at gmail.com>

> Hi,
>
> This is an up of this old thread. I have problems with vtkImageResample. I
> wrote an XML that exposes this filter to ParaView, and
> vtkImageGaussianSource and vtkImageMagnitude too. Please, could you try that
> and tell me if you can reproduce this behaviour ?
> - Load plugin as XML
> - Create a Gaussian Source and Apply with default settings
> - Plug an Image Resample proxy to the Gaussian Source output
> - Set Spacing to 0.5 0.5 0.5
> - Apply.
>
> Then, a normal behaviour would be for ImageResample to produce a volume
> with Extent twice more than input, so dimension (256, 256, 256). This is not
> the case. Extent is blocked to 0 127 0 127 0 127. With the given spacing,
> the bounding box is smaller than the input! You can try with a down-sampling
> of the input: set Spacing to 2 2 2 in Image Resample object property panel,
> Apply. Extent is twice less than input, Spacing twice more: bounding box is
> the same, this behaviour is correct.
>
> It acts like there is a saturation of the output extent according to the
> input one. I didn't note that problem within a python script (outside
> ParaView) and with an VTK-only dependent executable.
>
> Find attached the XML.
>
> Thanks for your time!
> Best regards,
>
> Jerome
> WIndows XP SP3, ParaView CVS, VS2008X
>
>
> 2009/1/30 Bryn Lloyd <blloyd at vision.ee.ethz.ch>
>
>> 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/<http://www.vision.ee.ethz.ch/%7Eblloyd/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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