[vtkusers] ImagePlaneWidget mapping ImageData with 3 scalars to rgb

[Lars Matthäus]

Great, that worked! Never had the idea that it would be possible to set
just no color table at all...

Thanks very much,
Lars

Am 30.09.2015 um 21:00 schrieb DL I:
> Hi Lars,
> 
> I think the problem is the vtkLookupTable is meant to take a single
> component (scalar value) and map it to RGB.
> So even though the image has 3 unsigned char components, only the first
> component gets mapped through.  What you want
> to do in this case is just pass the image directly through without using
> a lookup table.  However, with 3D image data, you might
> not be able to do window levelling: not sure, just a hunch at this
> point.  Also, you dont need to set a vtkLookupTable to
> the vtkImageSlice's vtkImageProperty since the image is already 3
> unsigned char.
> The following worked for me:
> 
> #include <vtkImageMapToColors.h>
> #include <vtkImagePlaneWidget.h>
> #include <vtkImageData.h>
> #include <vtkSmartPointer.h>
> #include <vtkRenderWindow.h>
> #include <vtkRenderWindowInteractor.h>
> #include <vtkInteractorStyleImage.h>
> #include <vtkRenderer.h>
> #include <vtkImageMapper.h>
> #include <vtkImageSliceMapper.h>
> #include <vtkImageProperty.h>
> #include <vtkImageSlice.h>
> #include <vtkLookupTable.h>
> #include <vtkJPEGReader.h>
> 
> int main(void) {
> 
>   // Setup renderers
>   vtkSmartPointer<vtkRenderer> renderer =
> vtkSmartPointer<vtkRenderer>::New();
> 
>   // Setup render window
>   vtkSmartPointer<vtkRenderWindow> renderWindow =
> vtkSmartPointer<vtkRenderWindow>::New();
>   renderWindow->SetSize(800, 800);
>   renderWindow->AddRenderer(renderer);
> 
>   // Setup render window interactor
>   vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
>     vtkSmartPointer<vtkRenderWindowInteractor>::New();
>   renderWindowInteractor->SetRenderWindow(renderWindow);
> 
>     // create input
>     vtkSmartPointer<vtkJPEGReader> reader = 
> vtkSmartPointer<vtkJPEGReader>::New();
>    
> reader->SetFileName("/home/dean/files/repository/VTKData/Data/beach.jpg");
>     vtkImageData* id = reader->GetOutput();
>     reader->Update();
>     int* dim = id->GetDimensions();
> 
>     // image plane widget
>     vtkSmartPointer<vtkImagePlaneWidget> ipw = 
> vtkSmartPointer<vtkImagePlaneWidget>::New();
>     ipw->SetInteractor(renderWindowInteractor);
>     ipw->SetInput(reader->GetOutput());
>     ipw->SetPlaneOrientation(2);
>     ipw->GetColorMap()->SetLookupTable(NULL);
>     ipw->GetColorMap()->SetOutputFormatToRGB();
>     ipw->On();
> 
>     // slice mapper
>     vtkSmartPointer<vtkImageSliceMapper> imageMapper = 
> vtkSmartPointer<vtkImageSliceMapper>::New();
>     imageMapper->SetInput(reader->GetOutput());
> 
>     vtkSmartPointer<vtkImageSlice> image = 
> vtkSmartPointer<vtkImageSlice>::New();
>     image->SetMapper(imageMapper);
>     image->SetPosition(1.5 * dim[0], 0, 0); // shift in x direction
>     renderer->AddViewProp(image);
> 
>     // proper initial display
>     renderer->ResetCamera();
> 
>   // Render and start interaction
>      renderWindowInteractor->Initialize();
> 
>   renderWindowInteractor->Start();
> 
>   return EXIT_SUCCESS;
> }
> 
> - Dean
>                                                                                                             
> 1,5           Top
> 
> 
> 
> 
> On Wed, Sep 30, 2015 at 3:44 AM, Lars Matthäus <lars.matthaeus at web.de
> <mailto:lars.matthaeus at web.de>> wrote:
> 
>     Dear Dean,
> 
>     Thanks for your help! Unfortunately, it doesn't solve the problem. The
>     image in the vtkImagePlaneWidget is still not like the original rgb. I
>     attach again some screenshots for comparison (vtkImagePlaneWidget on the
>     left, vtkImageSliceMapper on the right). Is there anything else I
>     could try?
> 
>     Best,
>     Lars
> 
>     Am 29.09.2015 um 15:22 schrieb DL I:
>     > Lars,
>     > try changing your value and saturation ranges to something else, like (1,1)
>     > regards,
>     > Dean
>     >
>     > On Mon, Sep 28, 2015 at 10:29 AM, Lars Matthäus <lars.matthaeus at web.de <mailto:lars.matthaeus at web.de>
>     > <mailto:lars.matthaeus at web.de <mailto:lars.matthaeus at web.de>>> wrote:
>     >
>     >     I have a DataSet with 3 scalar components, e.g. from loading a stack of
>     >     rgb images with the vtkJPEGReader. I want to slice through it using a
>     >     vtkImagePlaneWidget. Unfortunately, I cannot get the widget to display
>     >     the rgb image; I only get a grey image.
>     >
>     >     I played with the vtkLookupTable::SetVectorModeToRGBColors successfully
>     >     to display the image as rgb using a vtkImageSliceMapper, but when I use
>     >     the same lookup table for the vtkImagePlaneWidget, I get a grey
>     >     image again.
>     >
>     >     I attach some java sample code comparing the vtkImagePlaneWidget and the
>     >     vtkImageSliceMapper as well as the output of the program.
>     >
>     >     Any help appreciated!
>     >     Lars
>     >
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