[IGSTK-Users] change luminosity and modify threshold in dicom images

[Patrick Cheng]

Hi Luca,

The DICOM image pixel is a single scalar value, it doesn't have a alpha 
value.

The best way to do that is to do a preprocessing of the image data, 
using a threshold to determine the alpha value of each pixel. And after 
that you can just use the vtkImageMapToColors and turn the map alpha to 
output on. You will be able to make the background transparent.

You can look into the ImageResliceObjectRepresentation to see how IGSTK 
works with those vtk filters.

Thank you,

Patrick

Luca Ramundo wrote:
> Hi Patrick..
> how are you? Excuse me if I'm disturbing you, but probably you can help 
> me. About two month ago, you told me how I can change the window/level 
> of the image representation to optimize the view for certain organs. Now 
> I have another similar problem: I'd like to set threshold values (to 
> don't visualize the black background from my dicom files) but I don't 
> know the way to do this. I read some documentation of classes in igstk 
> to try the solution at my problemI have not found the answer. What can 
> you tell me about this?
> Thanks a lot,
> Luca
> 
> cerca <http://translate.google.it/translate_s?hl=it&sl=it&tl=en&q=simile>
> 
>  > Date: Wed, 18 Mar 2009 13:36:13 -0400
>  > From: cheng at isis.georgetown.edu
>  > To: luca.ramundo at hotmail.it
>  > CC: igstk-users at public.kitware.com
>  > Subject: Re: [IGSTK-Users] change luminosity and increase threshold 
> in dicom images
>  >
>  > Hi Luca,
>  >
>  > You can change the window/level of the image representation to optimize
>  > the view for certain organs:
>  >
>  > imageRepresentation->SetWindowLevel(1000, 1000).
>  >
>  > Patrick
>  >
>  > Luca Ramundo wrote:
>  > > Hi guys...
>  > > I'm loading and visualizing a dicom serie, but these images seem too
>  > > much clear.. Is there a way to change luminosity, to increase 
> threshold
>  > > and to recognize organs in an optimal manner?
>  > >
>  > > 
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