[vtkusers] output surface coordinates for vtkSurfaceReconstructionFilter

[Ismail Elkhrachy]

Obada Mahdi wrote:
> Hello Ismail!
>
> On Thu, 7 Dec 2006, Ismail Elkhrachy wrote:
>> Is the output surface coordinates for vtkSurfaceReconstructionFilter 
>> scaled? If yes , how to get the surface coordinates according to the 
>> input surface coordinates?
>
> Apparently, origin and spacing are not propagated into the output data
> set for some reason by vtkSurfaceReconstructionFilter. They are,
> however, propagated to the output information vector of the algorithm.
> I am not sure whether vtkSurfaceReconstructionFilter should set up
> spacing and origin in the output data set, or whether vtkContourFilter
> (or the classes it delegates the actual work to) should honour the
> spacing and origin provided through the information vector, or both.
>
> Anyway, this has been reported both in the mailing list as well as in
> the bug tracker, see
>
> http://public.kitware.com/pipermail/vtkusers/2006-February/083627.html
> http://www.vtk.org/Bug/bug.php?op=show&bugid=2826&pos=0
>
> (I found those searching the mailing list archives, via the Kitware
> website, for "vtkusers vtkSurfaceReconstructionFilter spacing origin".)
>
> This explains the "scaling effect": If you have a look at the bounds of
> the contoured output data set from your previous message, which I am
> quoting below for reference, you will notice that they closely match the
> expected dimensions of the sampled distance function produced by
> vtkSurfaceReconstructionFilter, with respect to a sampling resolution.
>
> For example, given the input bounds
>
>> For example The bounds for the original input (x, y,z) data 
>> coordinates is :
>>
>> X_min = 1.037000, X_max =2.401000
>
> and a sampling spacing of 0.026, one would probably expect the output
> extent in x to be from 0 to (X_max-X_min)/0.026, which is 52. It turns
> out to be a bit larger
>
>> But for the output for the pt[0], pt[1], pt[2]) is:
>> X_min =0.000000, X_max =55.000000
>
> which looks like a result of an adjustment made by the filter:
>
> [Imaging/vtkSurfaceReconstructionFilter.cxx, lines 411ff]
> | 411 // allow a border around the volume to allow sampling around the 
> extremes
> | 412 for(i=0;i<3;i++)
> | 413 {
> | 414 bounds[i*2]-=this->SampleSpacing*2;
> | 415 bounds[i*2+1]+=this->SampleSpacing*2;
> | 416 }
>
>
> What you could try to fix this, is to obtain the output of
> vtkSurfaceReconstructionFilter after a forced pipeline Update() and set
> up spacing and origin manually, probably like this:
>
> | surf->Update();
> |
> | vtkImageData* signedDist = surf->GetOutput()->ShallowCopy();
> | vtkInformation* signedDistInfo = surf->GetOutputPortInformation();
> | signedDist->SetSpacing(signedDistInfo->Get(vtkDataObject::SPACING()));
> | signedDist->SetOrigin(signedDistInfo->Get(vtkDataObject::ORIGIN()));
> |
> | vtkContourFilter *cf=vtkContourFilter::New();
> | cf->SetInput(signedDist);
>
> In the output port information, spacing and origin are set to the sample
> spacing and top left of the padded bounding box, respectively.
>
> Note that I do not know anything about how the reconstruction filter
> works, so I am not sure how accurate the results of simply setting
> spacing and origin will be.
>
>
> Regards
>
> Obada
>
>
> On Wed, 6 Dec 2006, Ismail Elkhrachy wrote:
>> Date: Wed, 06 Dec 2006 08:57:04 +0100
>> From: Ismail Elkhrachy <I.Elkhrachy at tu-bs.de>
>> To: VTKMailList <vtkusers at vtk.org>
>> Subject: [vtkusers] Problem with surface coordinates from 
>> vtkContourFilter
>>
>> Dear friends,
>> I have a point cloud(x, y,z) that represents an object surface. After 
>> I use surface reconstruct filter (vtkSurfaceReconstructionFilter) , 
>> and as Amy told me how to get all the generated surface coordinate. 
>> It is working ok, Thanks again to Amy!!.
>>
>> But the output coordinates pt[0], pt[1], pt[2]) are not in the same 
>> coordinates system of original point cloud(x, y,z)polyDat1, Do you 
>> know how to get them in the same old coordinate system.
>> For example The bounds for the original input (x, y,z) data 
>> coordinates is :
>>
>> X_min = 1.037000, X_max =2.401000
>> Y_min = 2.508000 , Y_max =4.061000
>> Z_min = -19.063601 , Z_zmax =-18.101999
>> But for the output for the pt[0], pt[1], pt[2]) is:
>> X_min =0.000000, X_max =55.000000
>> Y_min =0.000000 , Y_max= 62.000000
>> Z_min =0.000000, Z_zmax= 38.941410
>> Ma code is:
>> vtkSurfaceReconstructionFilter *surf = 
>> vtkSurfaceReconstructionFilter::New();
>>
>> surf->SetInput(polyData1);
>> surf->SetSampleSpacing(0.026);
>> surf->GetReleaseDataFlag();
>> surf->Update();
>>
>> vtkContourFilter *cf=vtkContourFilter::New();
>> cf->SetInput(surf->GetOutput());
>> cf->SetValue (0, 0.0 );
>> cf->Update();
>>
>> vtkPoints *points = cf->GetOutput()->GetPoints();
>> int numPts = points->GetNumberOfPoints();
>> int i;
>> double pt[3];
>>
>> for (i = 0; i < numPts; i++)
>> {
>> points->GetPoint(i, pt);
>> printf("point %d: %f %f %f\n", i, pt[0], pt[1], pt[2]);
>> }
>>
>> I am using vtk 5.0.0 under MS Visual C++ 6.0, windows xp professional.
>>
>> Any suggestion will be appreciated. Thank you in advance.
>> Ismail
>>
>>
>>
>>
>>
>> M.Sc. Ismail Elkhrachy
>> PhD student
>>
>> Institut f?r Geod?sie und Photogrammetrie
>> Technische Universit?t Braunschweig
>> Gau?str. 22 38106 Braunschweig Germany
>>
>> Mob. : 0049 0163 3623486
>> Tel. : 0049 0531 3917497
>> Fax : 0049 0531 3917499
>> E-mail : I.Elkhrachy at tu-bs.de, I.Elkhrachy at yahoo.com
Thank you very much Obady for your help;
after using your solution i have got 6 errors, I am new by oop c++, 
could you please help me?
Thank you,
Ismail

Compiling...
Normals_curvatures.cxx
C:\Elkhrachy\PhD_Programs\SurfaceGeneration_Normals_Curvatures\Normals_curvatures.cxx(121) 
: error C2660: 'ShallowCopy' : function does not take 0 parameters
C:\Elkhrachy\PhD_Programs\SurfaceGeneration_Normals_Curvatures\Normals_curvatures.cxx(122) 
: error C2660: 'GetOutputPortInformation' : function does not take 0 
parameters
C:\Elkhrachy\PhD_Programs\SurfaceGeneration_Normals_Curvatures\Normals_curvatures.cxx(123) 
: error C2027: use of undefined type 'vtkInformation'
c:\program1\vtk\vtk-5.0\vtk\filtering\vtkalgorithm.h(39) : see 
declaration of 'vtkInformation'
C:\Elkhrachy\PhD_Programs\SurfaceGeneration_Normals_Curvatures\Normals_curvatures.cxx(123) 
: error C2227: left of '->Get' must point to class/struct/union
C:\Elkhrachy\PhD_Programs\SurfaceGeneration_Normals_Curvatures\Normals_curvatures.cxx(124) 
: error C2027: use of undefined type 'vtkInformation'
c:\program1\vtk\vtk-5.0\vtk\filtering\vtkalgorithm.h(39) : see 
declaration of 'vtkInformation'
C:\Elkhrachy\PhD_Programs\SurfaceGeneration_Normals_Curvatures\Normals_curvatures.cxx(124) 
: error C2227: left of '->Get' must point to class/struct/union
Error executing cl.exe.

ICP_3.exe - 6 error(s), 0 warning(s)


-- 
M.Sc. Ismail Elkhrachy
PhD student

Institut für Geodäsie und Photogrammetrie
Technische Universität Braunschweig
Gaußstr. 22   
38106 Braunschweig 
Germany

Mob.           : 0049 0163 3623486
Tel.           : 0049 0531 3917497
Fax            : 0049 0531 3917499
E-mail         : I.Elkhrachy at tu-bs.de, I.Elkhrachy at yahoo.com