[vtkusers] vtkImageTracerWidget ROI Problem

[Sercani]

Hi everyone;

I have a problem with vtkImageTracerWidget (i think).I am developing a multi
planar reconstitution project for CT datasets using vtk and java.I want to
draw a closed region on a vtkImageActor and then calculate the voxel count,
min , max scalar values in this region and the density of this region.I' ve
implemented the class below , but something goes wrong here so sometimes the
output of the textactor becomes: 

"n:0

min:1.0E299 HU

max:-1.0E299 HU

mean:0.0 HU

den:0.0 mm^3"

Sometimes it shows some other values, but i am not sure the accuracy of
them.I tried every possible combination with vtkExtractVOI,
vtkLinearExtrusionFilter etc. but couldn't manage to fix this.What is wrong
with this code? :

(Panel is an instance of vtkCanvas, and reslice is the active
vtkImageReslice)

 

 

import client3d.MPRPanel;

import vtk.vtkExtractVOI;

import vtk.vtkImageAccumulate;

import vtk.vtkImageStencil;

import vtk.vtkImageTracerWidget;

import vtk.vtkLinearExtrusionFilter;

import vtk.vtkPolyData;

import vtk.vtkPolyDataToImageStencil;

import vtk.vtkTextActor;

import vtk.vtkTextProperty;

 

public class DensityWidget {

 

    private vtkImageTracerWidget itw;

    private vtkExtractVOI extract;

    private vtkLinearExtrusionFilter extrude;

    private MPRPanel panel;

    private vtkPolyData poly;

    vtkImageStencil stencil;

    private double[] range;

    private double min;

    private double max;

    private double diff;

    private double avg;

    private double[] bounds;

    private vtkImageAccumulate accum;

    private vtkTextActor textActor;

    java.text.DecimalFormat df = new java.text.DecimalFormat("#00.0");

 

    public DensityWidget(MPRPanel panel) {

        this.panel = panel;

        itw = new vtkImageTracerWidget();

        extract = new vtkExtractVOI();

        extrude = new vtkLinearExtrusionFilter();

        poly = new vtkPolyData();

        stencil = new vtkImageStencil();

        accum = new vtkImageAccumulate();

        textActor = new vtkTextActor();

        createVTKPipeline();

    }

 

    public void createVTKPipeline() {

        extract.SetVOI(panel.getReslice().GetOutputExtent());

        extract.SetSampleRate(1, 1, 1);

        extract.SetInput(panel.getImagedata());

        extract.ReleaseDataFlagOff();

        extract.Update();

 

        this.range = extract.GetOutput().GetScalarRange();

        this.min = range[0];

        this.max = range[1];

        this.diff = max - min;

        this.avg = (max + min) * 0.5;

        this.bounds = extract.GetOutput().GetBounds();

 

        itw.SetCaptureRadius(100000);

        itw.GetGlyphSource().SetColor(1, 0, 0);

        itw.GetGlyphSource().SetScale(3.0);

        itw.GetGlyphSource().SetRotationAngle(45.0);

        itw.GetGlyphSource().Modified();

        itw.ProjectToPlaneOn();

        itw.SetProjectionNormalToZAxes();

        itw.SetViewProp(panel.getImageactor());

        itw.SetInput(panel.getImagedata());

        itw.SetInteractor(panel.getIren());

        itw.PlaceWidget();

        itw.SnapToImageOn();

        itw.AutoCloseOn();

        itw.AddObserver("EndInteractionEvent", this, "AdjustROI");

        itw.On();

 

        extrude.SetScaleFactor(1);

        extrude.SetExtrusionTypeToNormalExtrusion();

        extrude.SetVector(0, 0, 1);

 

        stencil.SetInputConnection(extract.GetOutputPort());

        stencil.ReverseStencilOff();

        stencil.SetBackgroundValue(128);

 

        accum.SetInputConnection(extract.GetOutputPort());

        accum.ReverseStencilOff();

        accum.SetComponentSpacing(1, 0, 0);

        accum.SetComponentExtent(0, (int) diff, 0, 0, 0, 0);

        accum.SetComponentOrigin(min, 0, 0);

        accum.ReleaseDataFlagOff();

        accum.ReverseStencilOff();

        accum.IgnoreZeroOff();

 

        vtkTextProperty prop = new vtkTextProperty();

        prop.SetFontSize(10);

        prop.SetFontFamilyToArial();

        prop.BoldOff();

        prop.ItalicOff();

        prop.ShadowOff();

        prop.SetLineSpacing(0.9);

        prop.SetJustificationToLeft();

        prop.SetVerticalJustificationToTop();

        prop.SetColor(1, 1, 0);

        textActor.ScaledTextOff();

        textActor.SetPosition(100, 40);

        textActor.SetTextProperty(prop);

 

        panel.GetRenderer().AddActor(textActor);

        panel.resetCameraClippingRange();

        panel.Render();

    }

 

    public void AdjustROI() {

 

        int closed = itw.IsClosed();

        if (closed == 1) {

            itw.GetPath(poly);

 

            extrude.SetInput(poly);

            extrude.Update();

 

            vtkPolyDataToImageStencil dataToStencil = new
vtkPolyDataToImageStencil();

            dataToStencil.SetInputConnection(extrude.GetOutputPort());

 
dataToStencil.SetOutputSpacing(extract.GetOutput().GetSpacing());

            dataToStencil.SetOutputOrigin(extract.GetOutput().GetOrigin());

 
dataToStencil.SetOutputWholeExtent(extract.GetOutput().GetExtent());

            dataToStencil.Update();

 

            stencil.SetStencil(dataToStencil.GetOutput());

            stencil.Update();

 

            accum.SetStencil(stencil.GetStencil());

            accum.Update();

            int aN = accum.GetVoxelCount();

            double amin[] = accum.GetMin();

            double amax[] = accum.GetMax();

            double amean[] = accum.GetMean();

            double den = Math.abs(amean[0]) * panel.getSpacing()[0] *
panel.getSpacing()[1] * panel.getSpacing()[2];

            String atext = "";

            atext += "n:";

            atext += aN;

            atext += "\n";

            atext += "min:" + /*df.format*/ (amin[0]) + " HU";

            atext += "\n";

            atext += "max:" + /*df.format*/ (amax[0]) + " HU";

            atext += "\n";

            atext += "mean:" + /*df.format*/ (amean[0]) + " HU";

            atext += "\n";

            atext += "den:" + /*df.format*/ (den) + " mm^3";

            System.out.println(atext);

            textActor.SetInput(atext);

            textActor.Modified();

            textActor.SetPosition(150, 60);

        } else {

            textActor.SetInput("no ROI");

        }

        panel.Render();

    }

 

    public void destroy() {

        itw.Off();

        textActor.VisibilityOff();

        extract.Delete();

        extrude.Delete();

        stencil.Delete();

        accum.Delete();

        textActor.Delete();

        itw.Delete();

    }

}

 

Thanks;

 

Sercan..

 

 

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