[vtkusers] A question about displaying Image using VTK

[15891495523 at 126.com]

Dear all 

    I feel confused when display a CT image using VTK. How can I make those black and gray part in the following picture invisible ? 
    The key part of my code is : 

vtkSmartPointer<vtkPiecewiseFunction> opacityTransferFunction = vtkSmartPointer<vtkPiecewiseFunction>::New(); 
        opacityTransferFunction->AddPoint(0,1200); 
        opacityTransferFunction->AddPoint(1200,0.4); 
        opacityTransferFunction->AddPoint(2000,0.2); 

        vtkSmartPointer<vtkColorTransferFunction> colorTransferFunction = vtkSmartPointer<vtkColorTransferFunction>::New(); 
        colorTransferFunction->AddRGBPoint(0,0,0.5,0); 
        colorTransferFunction->AddRGBPoint(60,1,0,0); 
        colorTransferFunction->AddRGBPoint(255,0.8,0.8,0.8); 


Thank you in advanced! 

ZhangQiang





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