[Dcmlib] Question about dicom imaging not being read correctly

[Jean-Pierre ROUX]

At 5:16 +0000 20/01/08, Neerav Patel wrote:
>Hi,
>Using GDCM I have loaded up the raw byte array but the problem is when
>I show the image the really white areas seem to be corrupted and have
>turned black.  Is there a setting that I havent set or something.
>Here is the code i have wrote:
>       f = GDCM_NAME_SPACE::File::New();


Hi, Neerav!

The following lines are probabely useless in your case :

=====================

>       f->SetLoadMode(GDCM_NAME_SPACE::LD_NOSEQ);
>       f->SetLoadMode(GDCM_NAME_SPACE::LD_NOSHADOW);
>       f->SetLoadMode(GDCM_NAME_SPACE::LD_NOSEQ | 
>GDCM_NAME_SPACE::LD_NOSHADOW);
>       f->SetLoadMode(GDCM_NAME_SPACE::LD_NOSHADOWSEQ);

====================
(and, anyway, you should just use *one* of them, not *all*, but the 
problem doesn't start from here.
Note : using
f->SetLoadMode(GDCM_NAME_SPACE::LD_NOSEQ | GDCM_NAME_SPACE::LD_NOSHADOW);
may, sometimes, save some CPU time if you're just interested in 
getting the pixels.)

What's the C++ type of imageData in :
imageData = fh->GetImageDataRaw();

GetImageDataRaw() returns an unsigned char*, and you have to cast it, 
according what you know about your image (8/16 bits, signed/unsigned).
A misusage of signed/unsigned could lead to see 'brighter pixels' as dark.
Use File methods to be sure.

--> How do you display the image?
(if vtk installed on your computer, could you run :
vtkgdcmViewer2 yourDicomFileName
and see if the displayed image looks OK.
If it doesn't, could send me a sample of your image, so I can check 
if somethind is going wrong with gdcm.

Thx
Jean-Pierre Roux
gdcm team


>       f->SetFileName( filename );
>       bool res = f->Load();
>       if ( !res ) {
>               f->Delete();
>               MessageBox( NULL, "DICOM NOT LOADED", NULL, MB_OK );
>               f = NULL;
>       }
>       if (!f->IsReadable()) {
>               MessageBox( NULL, "Sorry, not a Readable DICOM / ACR 
>File", NULL, MB_OK  );
>               f->Delete();
>               f = NULL;
>               return;
>       }
>       fh = GDCM_NAME_SPACE::FileHelper::New(f);
>       fh->SetKeepOverlays(false);
>       int nZ, sPP, planarConfig;
>       std::string pixelType;
>       imageWidth = f->GetXSize();
>       imageHeight = f->GetYSize();
>       nZ = f->GetZSize();
>       pixelType    = f->GetPixelType();
>       sPP          = f->GetSamplesPerPixel();
>       planarConfig = f->GetPlanarConfiguration();
>       int numberOfScalarComponents=f->GetNumberOfScalarComponents();
>       dataSize  = fh->GetImageDataRawSize();
>   imageData = fh->GetImageDataRaw();  // somewhat important : Loads
>the Pixels in memory !
>       if ( imageData == 0 ) {
>     MessageBox( NULL, "Was unable to read pixels ", NULL, MB_OK );
>         f = NULL;
>         return;
>  }
>
>Any help would be greatly appreciated.
>
>Thanks
>
>Neerav
>
>
><>
>
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  Jean-Pierre ROUX
   CREATIS - CNRS UMR 5220, INSERM U 630
   Laboratoire de Radiologie Experimentale
   Hopital Cardiologique
   28 Avenue du Doyen LEPINE
   B.P. Lyon-Montchat
   69394 Lyon Cedex 03
 
   Tel      : (+33) 04 72 35 74 12
   Fax      : (+33) 04 72 68 49 16
   URL      : http://www.creatis.univ-lyon1.fr/~jpr
   e-mail   : jpr at creatis.univ-lyon1.fr