[vtkusers] image moved afer an orientation change

Wed Dec 12 11:21:25 EST 2012

hi David:

saving the focal point did the trick!!! thanks very much
another question, how do I know the current slice number given the camera
parameters, for example, if my image have the following dimensions: (0,
256, 0, 256, 0, 199), the vtkInteractorStyleImage put the initial view in
the center using an axial orientation, this is the slice: 99. If I want the
user of my class can call a function named, for example:
set_slice(slice_number) where slice_number will be the number of the
desired slice to view, in this example a number between 0 and 199, how do I
do that?

On Wed, Dec 12, 2012 at 8:54 AM, David Gobbi <david.gobbi at gmail.com> wrote:

> Arrgh.  Another typo.  The code should be:
>
>   camera.SetFocalPoint(focal_point_for_axial_view)
>   style.SetImageOrientation(orientation_for_axial_view)
>
> And of course you should save the focal point for the
> previous orientation at the same time.
>
>  - David
>
> On Wed, Dec 12, 2012 at 6:53 AM, David Gobbi <david.gobbi at gmail.com>
> wrote:
> > On Wed, Dec 12, 2012 at 6:51 AM, David Gobbi <david.gobbi at gmail.com>
> wrote:
> >> The slicing and the panning are both controlled via the camera's focal
> >> point.  So slicing through the axial images causes the camera's
> >> FocalPoint to move in and out along the Z axis.  Then, when you switch
> >> to a new orientation, this "Z" position is centered in the window.
> >>
> >> If you want to avoid this, you should save the FocalPoint for each
> >> view orientation.  Then, you can restore the focal point before you
> >> call SetImageOrientation, e.g.
> >>
> >> camera.SetFocalPoint(focal_point_for_axial_view)
> >> camera.SetImageOrientation(orientation_for_axial_view)
> >>
> >>  - David
> >>
> >> On Wed, Dec 12, 2012 at 5:24 AM, José M. Rodriguez Bacallao
> >> <jmrbcu at gmail.com> wrote:
> >>> no one please, is this normal?
> >>>
> >>>
> >>> On Tue, Dec 11, 2012 at 9:45 AM, José M. Rodriguez Bacallao
> >>> <jmrbcu at gmail.com> wrote:
> >>>>
> >>>> hi folks, I am trying to implement a MPR viewer, so far so good. I am
> >>>> using the new image classes, this is test code:
> >>>>
> >>>> #!/usr/bin/env python
> >>>>
> >>>> import os
> >>>> import gdcm, vtkgdcm, vtk
> >>>>
> >>>>
> >>>> def key_press(sender, event):
> >>>>     key = interactor.GetKeySym()
> >>>>     style.SetCurrentRenderer(renderer)
> >>>>     if key == 'a':
> >>>>         print 'axial'
> >>>>         style.SetImageOrientation(
> >>>>             style.GetZViewRightVector(),
> >>>>             style.GetZViewUpVector()
> >>>>         )
> >>>>     elif key == 'c':
> >>>>         print 'coronal'
> >>>>         style.SetImageOrientation(
> >>>>             style.GetYViewRightVector(),
> >>>>             style.GetYViewUpVector()
> >>>>         )
> >>>>     elif key == 's':
> >>>>         print 'axial'
> >>>>         style.SetImageOrientation(
> >>>>             style.GetXViewRightVector(),
> >>>>             style.GetXViewUpVector()
> >>>>         )
> >>>>     render_window.Render()
> >>>>
> >>>>
> >>>>
> >>>> interactor = vtk.vtkRenderWindowInteractor()
> >>>> render_window = vtk.vtkRenderWindow()
> >>>> render_window.SetSize(400, 400)
> >>>> interactor.SetRenderWindow(render_window)
> >>>>
> >>>> style = vtk.vtkInteractorStyleImage()
> >>>> style.SetInteractionModeToImageSlicing()
> >>>> interactor.SetInteractorStyle(style)
> >>>> style.AddObserver('CharEvent', key_press)
> >>>>
> >>>> print 'sorting files...'
> >>>> path = '/home/jmrbcu/pictures/workpictures/dicom/BRAIN/'
> >>>> files = [os.path.join(path, x) for x in os.listdir(path)]
> >>>>
> >>>> ipp = gdcm.IPPSorter()
> >>>> ipp.SetComputeZSpacing(True)
> >>>> ipp.SetZSpacingTolerance(1e-3)
> >>>> result = ipp.Sort(files)
> >>>>
> >>>> sorted_files, zspacing = files, 0
> >>>> if result:
> >>>>     sorted_files = ipp.GetFilenames()
> >>>>     zspacing = ipp.GetZSpacing()
> >>>>     print 'files sorted, z spacing is: %s' % zspacing
> >>>> else:
> >>>>     print 'cannot sort files, this is not a valid volume'
> >>>>
> >>>> vtk_files = vtk.vtkStringArray()
> >>>> map(vtk_files.InsertNextValue, sorted_files)
> >>>>
> >>>> reader = vtkgdcm.vtkGDCMImageReader()
> >>>> reader.FileLowerLeftOn()
> >>>> reader.SetFileNames(vtk_files)
> >>>> reader.Update()
> >>>>
> >>>> spacing = reader.GetOutput().GetSpacing()
> >>>> change = vtk.vtkImageChangeInformation()
> >>>> change.SetInputConnection(reader.GetOutputPort())
> >>>> change.SetOutputSpacing(spacing[0], spacing[1], zspacing)
> >>>>
> >>>> im = vtk.vtkImageResliceMapper()
> >>>> im.SetInputConnection(change.GetOutputPort())
> >>>> im.SliceFacesCameraOn()
> >>>> im.SliceAtFocalPointOn()
> >>>> im.BorderOff()
> >>>>
> >>>> ip = vtk.vtkImageProperty()
> >>>> ip.SetColorWindow(255)
> >>>> ip.SetColorLevel(128)
> >>>> ip.SetAmbient(0.0)
> >>>> ip.SetDiffuse(1.0)
> >>>> ip.SetOpacity(1.0)
> >>>> ip.SetInterpolationTypeToLinear()
> >>>>
> >>>> ia = vtk.vtkImageSlice()
> >>>> ia.SetMapper(im)
> >>>> ia.SetProperty(ip)
> >>>>
> >>>> renderer = vtk.vtkRenderer()
> >>>> renderer.AddViewProp(ia)
> >>>> renderer.SetBackground(0 , 0, 0)
> >>>> render_window.AddRenderer(renderer)
> >>>>
> >>>> style.SetCurrentRenderer(renderer)
> >>>> style.SetZViewRightVector((1, 0, 0))
> >>>> style.SetZViewUpVector((0, -1, 0))
> >>>>
> >>>> style.SetXViewRightVector((0, 1, 0))
> >>>> style.SetXViewUpVector((0, 0, 1))
> >>>>
> >>>> style.SetYViewRightVector((1, 0, 0))
> >>>> style.SetYViewUpVector((0, 0, 1))
> >>>> style.SetImageOrientation(style.GetZViewRightVector(),
> >>>> style.GetZViewUpVector())
> >>>>
> >>>> # render the image
> >>>> renderer.ResetCamera()
> >>>> renderer.GetActiveCamera().ParallelProjectionOn()
> >>>> renderer.ResetCameraClippingRange()
> >>>> render_window.Render()
> >>>>
> >>>> interactor.Initialize()
> >>>> interactor.Start()
> >>>>
> >>>> the problems arise in this sequence:
> >>>>
> >>>> 1-  initially display the image: ok
> >>>> 2-  slice the image to a different slice with ctrl + mosue left: ok
> >>>> 3-  change the orientation to a different one (sagital or coronal,
> doesn't
> >>>> matter): this is the problem, orientation of the image is changed
> fine to
> >>>> the new one but the image is panned to a different position in the
> render
> >>>> window/renderer, not the center of it and in a different slice (the
> middle
> >>>> slice of the whole image)
> >>>>
> >>>> how can I avoid this, I mean, keep the image centered in the render
> >>>> window/renderer when the image orientation is changed and in the
> correct
> >>>> slice location?
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.vtk.org/pipermail/vtkusers/attachments/20121212/3aeadccf/attachment.htm>