[Insight-developers] GDCM problems with created dicom

[Lorensen, William E (Research)]

Mathieu,
I found the rest of the problem. The fix you provided was part of the
solution.

The other problem was that the pixel data in the dictionary for
group/element
7fe0 0010 had a representation of OB, not OW.

Most readers probably don't use this because this info can be derived from
other tags. Of course, this representation should vary depending on whether
the data is chars or shorts, but the current gdcm code won't let you change
a representation on the fly (as far as I can tell).

Since most medical data is 16 bit, I have changed the entry in the
dictionary from "OB" to "OW". Now I can generate files that the dicom3tools
can read.

I'll be checking in the changes this morning. It seems that I have to make a
trivial change to gdcmDefaultDicts.cxx.in to get the dictionary to rebuild.
The dependency on dicomV3.dic is missing.

Thanks for your help,

Bill

-----Original Message-----
From: Mathieu Malaterre [mailto:mathieu.malaterre at kitware.com]
Sent: Friday, December 17, 2004 10:55 AM
To: Lorensen, William E (Research)
Subject: Re: [Insight-developers] GDCM problems with created dicom


Done

$ cvs ci -m"BUG: The (Meta) Group Length tags contain a wrong lenght. 
Remove those tags from the output until the calculation of lenght is 
fixed in gdcm." itkGDCMImageIO.cxx itkGDCMImageIO.h
/cvsroot/Insight/Insight/Code/IO/itkGDCMImageIO.cxx,v  <-- 
itkGDCMImageIO.cxx
new revision: 1.43; previous revision: 1.42
/cvsroot/Insight/Insight/Code/IO/itkGDCMImageIO.h,v  <--  itkGDCMImageIO.h
new revision: 1.9; previous revision: 1.8


Lorensen, William E (Research) wrote:
> Yes, remove it for now and Ill try it.
> 
> 
> -----Original Message-----
> From: Mathieu Malaterre [mailto:mathieu.malaterre at kitware.com]
> Sent: Friday, December 17, 2004 10:39 AM
> To: Lorensen, William E (Research)
> Cc: insight-developers at public.kitware.com
> Subject: Re: [Insight-developers] GDCM problems with created dicom
> 
> 
> Lorensen, William E (Research) wrote:
> 
>>Mathieu,
>>I am having trouble with dicom files that we are creating. We are reading
>>dicoms, filtering them and creating new dicoms. We are passing the meta
> 
> data
> 
>>from the input to the output unmodified.
>>
>>If I run the dicom3tools dcdump program it fails on an assertion
>>
>>  dcdump 88_20_0.0625_1.dcm
>>you get an error messages that includes the phrase
>>  Assertion `bitsallocated <= bytesinword*8u' failed.
>>
>>I have tried to track things down further, and there is trouble in the
>>0x0002 area. I notice lots of FIXME comments in the gdcm code aroubd
>>processing of the 0x0002 tags.
>>
>>I know this message is a bit cryptic, but I'm on travel trying to get this
>>to work.
>>
>>Once I get back, I'll get you a sample file that is failing. I can force
> 
> the
> 
>>fail if I run the dicomSeriesReadSeriesWrite example.
>>
>>Have you seen problems like this?
> 
> 
> Unfortunately yes. There has been some mail on the gdcm mailing list 
> about this issue. e-film had also some trouble reading some DICOM imagea 
> produced by GDCM. It appears that the length of group 0x0002 was wrong. 
> The easy solution was simply to remove this tag from the output.
> 
> As a quick fix I can remove this tag also from itkGDCMImageIO, until 
> they rewrite the function that calculate the lenght of group 0x0002.
> 
> How does that sound ?
> 
> Mathieu
> 
>