[vtkusers] Pick a pixel in DICOM series

[Dean Inglis]

Hi Manuel,

the example code in
Wiki/VTK/Examples/Cxx/Images/PickingAPixel
provides the world coordinates of the picked location.  If you want image
i,j,k
 indices, you have to convert those coordinates yourself using the image
data's
origin and spacing information.
double* o = image->GetOrigin();
double* s = image->GetSpacing();
int x = static_cast<int>( ( x_world_pos - o[0] ) / s[0] + 0.5 );

do similar calcs for y and z.

regards,
Dean




On Thu, Jun 20, 2013 at 6:39 PM, Manuel Corrales
<manuelcorrales at gmail.com>wrote:

> Hello,
>
> I am displaying a DICOM series using vtk and "navigating" through the
> slices using mouse interaction. I need to pick a pixel from the displayed
> image, and I expected to get something like an array of coordinates e.g:
> (142, 342, 13) assuming I can use this to actually fetch the data from the
> vtkImageData structure.
>
> I tried to use the PickPixel and PickPixel examples from the wiki, but I
> get coordinates with negative numbers
>
> (Location: ( -49.3894, 37.2297, -97.2094 ))
>
> and don't know what to do with that. My goal is to be able to pick a
> pixel, get a coordinate and being able to use that coordinate to fetch the
> pixel color from the vtkImageData.
>
> Any hints?
>
> Regards,
> Manuel.
>
>
>
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