[Dcmlib] 0008 0070 Recognition code

[Jean-Pierre ROUX]

At 18:21 +0200 18/06/05, Luca Picello wrote:
>I do not have a clear idea on what is gdcm philosophy and i am 
>trying to learn it from examples.
>Can someone please explain to me what is the difference between:


Hi.

A 'gdcm::DicomDir' is used to hold a 'DICOMDIR'.
A DICOMDIR is a 'Dicom Objet', different of a 'Dicom Image'.
It's used to summarize the content of a 'root' directory' (mainly a CD Rom).
Roughly, it's a 'tree-like structure' :
-> Patient informations
--> Study Informations
---> Serie Informations
----> Image informations

In 'gdcmData', there is a file whose name id DICOMDIR.
You can see its content (as a standard Dicom Document) using
PrintFile filein=DICOMDIR
You can see it's tree-like structure using
PrintDicomDir filein=DICOMDIR detail=1 (or 2, or 3, etc)
depending on want you want to see (only the Patients, 
Patients+Studies, Patients+Studies+Series, etc)


>
>gdcm::DicomDir *e1;
>e1 = new gdcm::DicomDir( folder , true );
>std::string ssss = e1->GetEntryValue(0x0008,0x0070);
>
>and
>
>gdcm::File *f1= new gdcm::File( filename );
>f1 = new gdcm::DicomDir( fold.c_str() , true );
>std::string ssss = f1->GetEntryValue(0x0008,0x0070);
>
>it seems that if I try to access to the "directory" map of dicom 
>tags it does not work. instead working on a single file it works.why?

Only a few tags are stored in a DICOMDIR, and, anyway, they are 
inside a 'Sequence' (VR='SQ').

A DICOMDIR is mainly used to allow the user seeing at a glance what 
the directory contains and choosing what images he want to work with.
He will have then to 'read the header', and, when he is sure, to 
bring the pixels in memory, using the methods of gdcm::FileHelper.

HTH.

Jean-Pierre Roux

>thank you,
>
>Luca
>
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   Jean-Pierre ROUX
   CREATIS - CNRS UMR 5515, INSERM U 630
   Laboratoire de Radiologie Experimentale
   Hopital Cardiologique
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   B.P. Lyon-Montchat
   69394 Lyon Cedex 03
 
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