[vtkusers] Pixel Value

[Mathieu Malaterre]

2009/1/29 Sercani <sercanimailgroups at gmail.com>:
> Hi Everyone;
>
> I'm developing a DICOM viewer using Java and VTK and i need to show the
> pixel and hounsfield unit value of a clicked point. I' ve done the exactly
> same thing that Mark Wyszomierski   described here:
> http://devsample.org/index.php?option=com_content&task=view&id=48&Itemid=27
> and i get the correct pixel value(at least i hope so) but i couldn't convert
> it to hounsfield unit using this formula: hu= pixel*slope+intercept . Bone
> value must be over +400 hu, but i get negative values. Actually i have
> implemented the MPR with vtkImagePlaneWidget(s) too and it shows the real
> hounsfield unit value of the clicked point and for example the bone value
> changes while dragging the mouse on a bone but at my implemantation it
> always show the same value (pixel value is 255 and hu is -700 or something
> like this). How can i convert the pixel value to hounsfield unit or how can
> i get the real scalar values of a clicked point of CT data set?

Simply use vtkGDCMImageReader, it will apply the linear transformation
(Rescale Slope & Rescale Intercept ) automatically.

-> http://gdcm.sourceforge.net/html/classvtkGDCMImageReader.html

and

-> http://apps.sourceforge.net/mediawiki/gdcm/index.php?title=GDCM_Release_2.0

HTH
-- 
Mathieu