[Dcmlib] Signed Images

[Mathieu Malaterre]

For the window/level is is pretty easy:

double range[2];
my_function(range, image);
// range now contains the pixel value min and pixel value max.

level = (range[1]+range[0] )/2
window = range[1]-range[0]

In theory there is a window/level tag in DICOM but I don't trust them :P

HTH
Mathieu

On Jun 14, 2005, at 11:38 AM, Aris Basic wrote:

> I have some of my images havnot tested it with gdcm provided images 
> will probably do it and compare with vtkgdcmViewer.
> IM trying to display them with OpenGL (creating and RECT texture from 
> pixel data [ opengl supposedly shoudl be able to
> deal with signed pixel data , but doesnt look like its doing )
> (i tryed too figgure out how is VTK donig the W/L transfomration and 
> rest but did not have luck finding that piece of code quickly :)
>
>
> Jean-Pierre Roux wrote:
>
>> Aris Basic wrote:
>>
>>> is gdcm doing any conversion on pixel data from signed 
>>> (pixelrepresentation == 1) images ?
>>> pixelrepresentation == 0 images i can display nicely but 
>>> representation 1 they come up strange :(
>>
>>
>>
>> gdcm doesn't make any transformation for 'signed pixels'.
>> It's up to the user to deal with the sign.
>> How do you display the image?
>> Did you try with vtkgdcmViever? (of course, you need VTK ...)
>>
>> In our test data set ( gdcmData), there are a few 'signed pixels' 
>> images :
>>
>> MR-MONO2-16-head.dcm CT-MONO2-16-chest.dcm
>> CT-MONO2-16-ankle.dcm  CT-MONO2-16-ort.dcm
>> CT-MONO2-16-brain.dcm
>> GE_RHAPSODE-16-MONO2-JPEG-Fragments.dcm 
>> GE_GENESIS-16-MONO2-Uncompressed-UnusualVR.dcm
>> GE_GENESIS-16-MONO2-WrongLengthItem.dcm 
>> PICKER-16-MONO2-No_DicomV3_Preamble.dcm
>> 012345.002.050.dcm
>>
>> Did you try to display them?
>> HTH.
>>
>> Jean-Pierre
>>
>>>
>>> jsut trying to find a bug :) not pointing fingers
>>
>>
>> Thx for reporting it.
>> Could you send us one of your images, so we can check 'at home' if 
>> there is any problem.
>>
>>>
>>>
>>> Aris
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>>> Dcmlib at creatis.insa-lyon.fr
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>>>
>
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