[vtkusers] vtkImageIslandRemoval2D,y-z plane,black screen

[petr zlamal]

Hello VTKuser,

I have some problem with vtkImageIslandRemoval2D in my code. If actor 
input is a vtkImageThreshold output, then the scene is rendered and 
slices scrolling by keys "n" a "p" are right (in y-z plane). When actor 
input is a vtkImageIslandRemoval2D output, then the first slice is 
rendered right and next slices are only black. I assume that imageIsland 
filter only filling small area and in my configuration 
(SetAreaThreshold(0)), would theoretically not have to do anything. Why 
all slices (except for the first slice) in y-z plane are black, while 
after binary threshold are correct displayed????

Thanks Vepro

My simple code:

#!/usr/bin/env python
import vtk

def KeyPress(obj,event):
    global slice
    global ia
    global ren
    global camera
        key=obj.GetKeySym()
        if (key=="z"):
                exit
        elif key=="n":
                slice=slice+1
                ia.SetDisplayExtent(slice,slice,0,320,0,29)
                print "You pressed n. Current slice is now",slice
                ren.ResetCamera()
                renWin.Render()
        elif key=="p":
                slice=slice-1
                ia.SetDisplayExtent(slice,slice,0,320,0,29)
                ren.ResetCamera()
                renWin.Render()
                print "You pressed p. Current slice is now",slice
     

slice=140
iren=vtk.vtkRenderWindowInteractor()
iren.AddObserver("KeyPressEvent", KeyPress)

reader=vtk.vtkBMPReader()   #8bit bmp data set
reader.SetDataExtent(0,320,0,320,0,29)
reader.SetFilePrefix("./bone/bone")
reader.SetFilePattern("%s.%d")
reader.SetDataSpacing(1,1,1)
reader.GetOutput().Update()

ren=vtk.vtkRenderer()
ren.SetBackground(1,0,0)

binthreshold=vtk.vtkImageThreshold()   #binary threshold
binthreshold.SetInputConnection(reader.GetOutputPort())
binthreshold.ThresholdBetween(30,255)
binthreshold.SetInValue(255)
binthreshold.SetOutValue(0)
binthreshold.ReleaseDataFlagOff()

island2=vtk.vtkImageIslandRemoval2D()
island2.SetInputConnection(binthreshold.GetOutputPort())
island2.SetIslandValue(0)
island2.SetReplaceValue(255)
island2.SetAreaThreshold(0)
island2.SquareNeighborhoodOn()

ia=vtk.vtkImageActor()
ia.SetInput(island2.GetOutput())
ia.SetDisplayExtent(slice,slice,0,320,0,29)

camera=vtk.vtkCamera()
ren.AddActor(ia)
ren.SetActiveCamera(camera)
camera.Yaw(90)
ren.ResetCamera()
renWin = vtk.vtkRenderWindow()
renWin.AddRenderer(ren)
iren.SetRenderWindow(renWin)
renWin.Render()
iren.Start()
iren.Initialize()