[vtkusers] Scale an image.

[Ana Sandro]

Hi David,

   Thank you very much for your response.I've been trying this way but I 
have some roblems and I'm really confused.

When I introduce this part to my pipeline the program shows the scaled image 
only for less than a second and then it disappeares,only the target_image 
remains on the screen.I have no time to observe if the scaled one is well 
magnified and I don't get any error message. Is it possible that 
vtkImageReslice interfere with any other object of my progam?.I've tried 
calling vtkImageReslice->SetOutputExtent(),reslice->SetOutputOrigin() and 
reslice->SetOutputSpacing() too because i read at old posts it's necessary 
to later correct use of vtkImageBlend but the result doesn't change.

On the other hand if I try to reslice one 2D image to the size of another 
and only visualize the scaled one there's no problem.Then I've to use the 
vtkTransform to Translate and Scale the image in order to it appears inside 
of the visualization area of the RenderWindow.(Another question is how to 
calculate the values to these methods,I don't know,I examined several values 
till I got right).Whereas If I use vtkTransform in my pipeline the scaled 
image directly doesn't appear neither for that first second,maybe because I 
don't find right values to tranlate it?.

I know I've a lot of doubts,I hope not to sound tedious and express myself 
clearly.I add my code in case it helps to understand me.I'd apreciate any 
clue.
Thank you .

//I obtain target_image at connector1
typedef signed short InputPixelType;
typedef unsigned short OutputPixelType;
typedef itk::Image< InputPixelType, 3 > InputImageType;
typedef itk::Image< OutputPixelType, 3 > OutputImageType;
typedef itk::RescaleIntensityImageFilter< InputImageType, OutputImageType > 
RescaleFilterType;
RescaleFilterType::Pointer rescaleFilter = RescaleFilterType::New();
typedef itk::Image<signed short,3> ImageType1;
typedef itk::ImageFileReader<ImageType1> ReaderType1;
typedef itk::ImageToVTKImageFilter<OutputImageType> ConnectorType1;
ReaderType1::Pointer reader1= ReaderType1::New();
ConnectorType1::Pointer connector1= ConnectorType1::New();
reader1->SetFileName("D:\\ana\\Imagenes\\03091536\\serieCT\\serieCT.img");
rescaleFilter->SetInput( reader1->GetOutput() );
rescaleFilter->SetOutputMinimum( 0 );
rescaleFilter->SetOutputMaximum( 4000 );
rescaleFilter->Update();
connector1->SetInput( rescaleFilter->GetOutput() );

//I obtain image to scale at connector
typedef itk::Image<unsigned short,3> ImageType;
typedef itk::ImageFileReader<ImageType> ReaderType;
typedef itk::ImageToVTKImageFilter<ImageType> ConnectorType;
ReaderType::Pointer reader= ReaderType::New();
ConnectorType::Pointer connector= ConnectorType::New();
reader->SetFileName("D:\\ana\\Imagenes\\03091536\\seriePET\\seriePET.img");
connector->SetInput( reader->GetOutput() );

//***Here I try to reslice.I've tried after map to colors too but no 
change***
   //vtkTransform* transform= vtkTransform::New();
   //transform->Identity();
   //transform->Scale(1.4,1.4,1);
   //transform->Translate(-200,200,0);
vtkImageReslice *reslice = vtkImageReslice::New();
reslice->SetInput(connector->GetOutput());
   //reslice->SetResliceTransform(transform);
reslice->SetInformationInput(connector1->GetOutput());
reslice->SetInterpolationModeToLinear();
   //reslice->SetOutputExtent(0,511,0,511,0,0);
   //reslice->SetOutputOrigin(0,0,0);
   //reslice->SetOutputSpacing(1,1,1);

//Make lookupTable to map target_image by gray scale.
vtkLookupTable* table1 = vtkLookupTable::New();
table1->SetNumberOfTableValues(256);
table1->Build();
table1->SetTableValue(0,r/255,g/255,b/255,1.0);
for(i=1;i<256;i++) {

	r++;
	g++;
	b++;
	indice=i;
	table1->SetTableValue(indice,r/255,g/255,b/255,1.0);
}
table1->SetTableRange(0,4000);
table1->SetAlphaRange(1.0,1.0);

//MakeLookupTable to map scaled image with color.
vtkLookupTable* table = vtkLookupTable::New();
r=0;
g=0;
b=254;
table->SetNumberOfTableValues(256);
table->Build();
table->SetTableValue(0,r/255,g/255,b/255,1.0);
for(i=1;i<128;i++) {

	g=(g+2);
	b=(b-2);
	indice=i;
	table->SetTableValue(indice,r/255,g/255,b/255,1.0);
}
table->SetTableValue(128,r/255,g/255,b/255,1.0);
for (i=129;i<256;i++) {

	r=(r+2);
	g=(g-2);
	indice=i;
	table->SetTableValue(indice,r/255,g/255,b/255,1.0);
}
table->SetTableRange(0,2500);
table->SetAlphaRange(1.0,1.0);

//map both images with their color scale.
vtkImageMapToColors* mapper = vtkImageMapToColors::New();
mapper->SetInput(reslice->GetOutput());
mapper->SetLookupTable(table);
vtkImageMapToColors* mapper1 = vtkImageMapToColors::New();
mapper1->SetInput(connector1->GetOutput());
mapper1->SetLookupTable(table1);

//blend both images
vtkImageBlend* blend = vtkImageBlend::New();
blend->SetOpacity(0, 0.5);
blend->SetOpacity(1, 0.5);
//I had to put AddInmput(0,---) instead SetInput(0,---),SetInput(1,---) to 
solve this error:
//ERROR: In 
D:\ana\Programas\VTK-5.0.0\Filtering\vtkDemandDrivenPipeline.cxx,
//line 774
//vtkStreamingDemandDrivenPipeline (0x02A79170): Input for connection index 
0
//on input port index 1 for algorithm vtkImageBlend(0x02A76480) is of type
//vtkImageData, but a vtkImageStencilData is required.

blend->AddInput(0,mapper1->GetOutput());
blend->AddInput(0,mapper->GetOutput());

//Finally I visualize one 2D orthogonal plane of the volume image.
vtkImageViewer2* viewer= vtkImageViewer2::New();
vtkRenderWindowInteractor* 
renderWindowInteractor=vtkRenderWindowInteractor::New();
viewer->SetupInteractor( renderWindowInteractor);
viewer->SetInput( blend->GetOutput() );
orientacion=atoi(argv[1]);
viewer->SetSliceOrientation(orientacion);
slice=atoi(argv[2]);
viewer->vtkImageViewer2::SetSlice(slice);
viewer->Render();
viewer->SetColorWindow(255);
viewer->SetColorLevel(128);
renderWindowInteractor->Start();
return 0;





>From: David Gobbi <dgobbi at atamai.com>
>To: Ana Sandro <garufa7000 at hotmail.com>
>CC: vtkusers at vtk.org
>Subject: Re: [vtkusers] Scale an image.
>Date: Thu, 23 Mar 2006 10:56:52 -0500
>
>Hi Ana,
>
>You can use vtkImageReslice to resample the first image so that it matches 
>the second:
>
>vtkImageReslice *reslice = vtkImageReslice::New();
>reslice->SetInput(image_to_scale);
>reslice->SetResliceTransform(transform);
>reslice->SetInformationInput(target_image);
>reslice->SetInterpolationModeToLinear();
>
>blend->SetInput(0, target_image);
>blend->SetInput(1, reslice->GetOutput());
>
>The "transform" can be used to control the position and scale of the first 
>image with
>respect to the second image, and vtkImageReslice makes sure that the one 
>image is
>resampled to match the other (and possibly cropped or padded, depending on 
>how
>much the transform magnifies or shrinks the image).
>
>- David
>
>
>Ana Sandro wrote:
>>Hello everybody,
>>
>>    My question is how to make an image bigger or smaller without using an 
>>actor?.
>>I use vtkImageviewer2 to visualize the final image and what I put into it 
>>is this image blendeed with another one.So, I need to sclae one of them in 
>>order to they both have the same size before to put them into 
>>vtkImageBlend.I have problems to apply vtkTransform.Someone could help 
>>me?I'd be so gatefull.
>>Thank you to all.
>>
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