[vtkusers] How do we change brightness and contrast in a Image?

[Rodrigues, Jason (MED)]

Hello all,
I have a basic query, I am sure youll be in a position to guide me better. 
How do I change the brightness and contrast of a image stored in
vtkImageData Object? What is the pipe line to render the same on to a panel
or window? 



import vtk.*;
import javax.swing.*;
import java.awt.event.*;

public class ImageDataDisplay {
   vtkImageData imagedata;
   JFrame mainframe;
   vtkPanel panel;
   vtkColorTransferFunction  LUT1;
   vtkImageMapToColors mapToRGBA1;
    vtkImageCast cast1;
    vtkImageMapper imgMapper;
    vtkLookupTable lut;
     vtkActor2D actor;
     vtkRenderer ren;

    public ImageDataDisplay(ImageVolume iv) {
              mainframe = new JFrame("VTKPANEL");
               panel = new vtkPanel();
              panel.addMouseMotionListener(new MouseMotionAdapter(){
                  public void mouseDragged(MouseEvent me){

                      int x = me.getX();
                      int y = me.getY();
                     LUT1 = new vtkColorTransferFunction();
                      LUT1.AddRGBPoint (8000.0, 0.2, 0.2, 0.2);
                      LUT1.AddRGBPoint  ( 6424.0, 0.9, 0.9, 0.9);
                      LUT1.AddRGBPoint  (6324.0, 0.0, 0.0, 1.0);
                      LUT1.AddRGBPoint ( 6224.0, 0.0, 1.0, 0.0);
                      LUT1.AddRGBPoint    (6154.0, 1.0, 1.0, 1.0);
                      LUT1.AddRGBPoint    (2153.0, 0.8, 0.8, 0.8);
                      LUT1.AddRGBPoint    (0.0,0.5, 0.5, 0.5);
                       dorender();
                  }
              });
              mainframe.getContentPane().add(panel);
                     int slices = iv.noOfImages;
                     int height = iv.getImages(0).getHeight();
                     int width = iv.getImages(0).getWidth();
                     short[][][] vtkPix = new short[slices][height][width];

        // 
                      for(int i=0; i<iv.noOfImages; i++) {
                             ImageClass ic = iv.getImages(i);
                             super.setImage(ic);
                             int k = 0;
                             for(int j=0; j<iht; j++) {
                               for(int l=0; l<iwt; l++) {
                                short val = (short) (pixelint[k++] &
0x7fff);
                                      vtkPix[i][j][l] = val;
                                }
                            }

                      }

                 imagedata = new vtkImageData();
                  imagedata.SetWholeExtent(0,width-1,0,height-1,0,slices-1);
                  imagedata.SetExtent(0,width-1,0,height-1,0,slices-1);
 
imagedata.SetUpdateExtent(0,width-1,0,height-1,0,slices-1);
                  imagedata.SetScalarType(5);
                  imagedata.AllocateScalars();

                         int id = 0;
                         for(int i = 0; i < slices; i++) {
                            for(int j = iht-1;j >0 ; j--) {
                                  for(int k = 0; k <width; k++) {
                                         double val =
(double)vtkPix[i][j][k];
 
imagedata.GetPointData().GetScalars().SetScalar(id,val);
                                         id++;
                                  }
                              }
                          }
                     //#   create a color lookup table
            LUT1 = new vtkColorTransferFunction();
            LUT1.AddRGBPoint (0.0, 0.2, 0.2, 0.2);
            LUT1.AddRGBPoint  (2153.0, 0.9, 0.9, 0.9);
            LUT1.AddRGBPoint  (6154.0, 0.0, 0.0, 1.0);
            LUT1.AddRGBPoint ( 6224.0, 0.0, 1.0, 0.0);
            LUT1.AddRGBPoint    (6324.0, 1.0, 1.0, 1.0);
            LUT1.AddRGBPoint    (6424.0, 1.0, 0.0, 0.0);
            LUT1.AddRGBPoint    (8000.0, 2.0, 0.0, 0.0);
                          dorender();


                }

                public void dorender() {




            mapToRGBA1 = new vtkImageMapToColors();
		mapToRGBA1.SetInput(imagedata);
		mapToRGBA1.SetLookupTable(LUT1);
                mapToRGBA1.SetOutputFormatToRGBA();
                imagedata = mapToRGBA1.GetOutput();

           cast1 = new vtkImageCast ();
		cast1.SetInput(mapToRGBA1.GetOutput());
		cast1.SetOutputScalarType(5);
		imagedata= cast1.GetOutput();
                imagedata.Update();

          imgMapper = new vtkImageMapper();
             imgMapper.SetInput(imagedata);
             imgMapper.SetColorWindow(255.0);
             imgMapper.SetColorLevel(127.0);


            actor = new vtkActor2D();
                 actor.SetMapper(imgMapper);

             ren=panel.getRenderer();
                  ren.AddActor2D(actor);
                  ren.Render();




                  mainframe.addWindowListener(new WindowAdapter() {
                            public void windowClosing(WindowEvent we) {
                                 mainframe.dispose();
                            }
                    });

                        mainframe.setSize(512,  512+27);
                          mainframe.setVisible(true);
                          mainframe.setResizable(false);
                          mainframe.pack();
                          mainframe.show();



           }


 }


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