[vtkusers] How to threshold vtkimage data

[Jim Peterson]

Ali Habib wrote:
> Hi All,
>  
> I read a series of DICOM files , and I want to apply threshold (for 
> further segmentation) but the below cod not effect any more
>  
>  vtk.vtkDICOMImageReader VDR = new vtk.vtkDICOMImageReader();
>             VDR.SetDirectoryName(@"E:\Master 
> Degree\DataSet\case2\DICOM\PA1\ST1\SE2");
>             VDR.SetDataOrigin(0, 0, 0);
>             VDR.Update();
>  
>             vtkImageThreshold VIT = new vtkImageThreshold();
>           //  VIT.ThresholdBetween(-300, 300);
>             VIT.ThresholdByLower(100);
>             VIT.SetInputConnection(VDR.GetOutputPort());
>            
>             VIT.Update();
>  
>             vtk.vtkImageIslandRemoval2D ImageIslandRemoval2D = new 
> vtk.vtkImageIslandRemoval2D();
>             ImageIslandRemoval2D.SetInput(VIT.GetOutput());
>             ImageIslandRemoval2D.SetAreaThreshold(1000);
>  
>             vtk.vtkContourFilter skinExtractor = new 
> vtk.vtkContourFilter();
>             
> skinExtractor.SetInputConnection(ImageIslandRemoval2D.GetOutputPort());
>             //skinExtractor.SetValue(0, 500); // 1123 extract 
> mandible  //
>             skinExtractor.GenerateValues(1, -300, 300);
>             skinExtractor.ComputeGradientsOn();
>  
> any suggestion pelase
So what were you expecting to have happen and what happened for you? 
What did you change to cause this to "not effect any more"? Have you 
been reading the vtk class documentation? See 
http://www.vtk.org/doc/nightly/html/classvtkContourFilter.html for the 
contour filter class doc. what are you expecting 
GenerateValues(1,-300,300) to set as contour values? Does that sound 
like a appropriate use of that function? how is one output value 
supposed to include the min and max values?

My gut feeling is the island filter with threshold 1000 is removing all 
features.

HTH,
Jim