[Insight-users] Confidence Connected Seed Coordinates

[Cameron Burnett]

Oh ok. So there is no way to perhaps extract a pixel at a certain physical coordinate, from the ImageSeriesReader object ?? I had a look at the doxygen documentation for itk::ImageSeriesReader but there wasn't any method like that.

The problem is that I'm doing this with 3D interaction. At the moment I don't have any 2D viewports at all. In order to find a seed point, the only logical thing I could think of was a vtkPointWidget. If that doesn't end up working then I'm not sure if it would be possible to do 3D region growing at all. Unless I can guess the seed point.

Any ideas??

Thanks.



> Date: Mon, 14 Apr 2008 10:16:44 -0400
> From: bill.lorensen at gmail.com
> To: w_e_b_m_a_s_t_e_r_6_9 at hotmail.com
> Subject: Re: [Insight-users] Confidence Connected Seed Coordinates
> CC: insight-users at itk.org
> 
> Cameron,
> 
> The Seed coordinates are in pixels, not physical coordinates. IN
> addition, VTK flips the image, so you  will need to flip your Y pixel
> coordinate.
> 
> We should probably add a method to the filters with Seeds to accept
> physical coordinates. Please add a feature request in the ITK bug
> tracker.
> 
> This page explains how to submit a bug:
> http://www.itk.org/Wiki/ITK_Procedure_for_Contributing_Bug_Fixes
> 
> Thanks,
> 
> Bill
> 
> 
> On Mon, Apr 14, 2008 at 9:56 AM, Cameron Burnett
> <w_e_b_m_a_s_t_e_r_6_9 at hotmail.com> wrote:
> >
> > Hi,
> >
> > I'm just wondering about the coordinate system of the confidence connected
> > algorithm. I'm using a vtkPointWidget to select a seed point, and according
> > to the point widget, my XY coordinates range from about -45,413 (top-left)
> > to 413,-45 (bottom-right).... and also a z coordinate which I've got as 7.5
> > (middle slice).
> >
> > Now, when I plug that into the confidence connected SetSeed() method, I
> > don't think the two coordinate systems are matching up because my results
> > are a bit strange.
> >
> >
> > The following picture is an image of two legs, and you can see the
> > vtkPointWidget being positioned in the center of the femur.
> >
> > http://img382.imageshack.us/img382/2118/dicomimgaw7.jpg
> >
> > This is the result of a multiplier of 0.1, followed by a multiplier of 2.
> >
> > http://img397.imageshack.us/img397/9743/outputvtk01multiplierwd7.jpg
> > http://img383.imageshack.us/img383/6727/outputvtk2multiplierfs6.jpg
> >
> > (Note: I think these may be a bit pixely due to the compression on
> > imageshack, but the actual ones are just 2 solid colours)
> >
> >
> > What I conclude from that is that the blue area is in fact the area that has
> > been seeded, not the red area. Therefore that is why I believe that I have
> > some sort of problem with the coordinates not matching. What do I have to do
> > to make sure the point widget and the SetSeed() method both match up??
> >
> > And I also don't know why there are 2 colours in the vtk file, when one
> > should obviously be transparent. Is that one easy to answer?
> >
> >
> > Thanks for any help,
> > Cameron.
> >
> >
> >
> > ________________________________
> > Grab it. You dream job is up for grabs.
> > _______________________________________________
> > Insight-users mailing list
> > Insight-users at itk.org
> > http://www.itk.org/mailman/listinfo/insight-users
> >
> >

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