[Insight-users] Re: [Insight-developers] GDCM update / JPEG2000 (OpenJPEG)

[Mathieu Malaterre]

Sorry I was not clear enough. So yes adding support for JPEG2000 image 
would require adding a full new JPEG2000 library (which does not deal at 
all with the old style JPEG library from IJG). For more info please go 
to http://www.openjpeg.org

Disk space (openjpeg 1.0):
$ du -sk libopenjpeg
returns 545k (373k was for the old 0.97 openjpeg lib, sorry).

As for the maintenance, I would say this is just as troublesome as the 
JPEG library. The authors of the library recently updated the library to 
1.0 so effectively it means this is a fairly new library. I believe all 
the internals are there at least for the limited purpose I needed in GDCM.

Anyway Antonin, François-Olivier or Hervé could you comment on the 
maintenance of OpenJPEG. What are the current tasks being done on 
OpenJPEG, is the API suppose to change any time soon ? How about 
streaming support (JPEG stream is not contiguous(*)) ?

As for the option to use externally I'd say -as usual- this is very 
dangerous and it will make us more work to support all the different 
version. Also OpenJPEG is not available in any Linux distro -as far as I 
can tell- so I don't see yet the need to support external library.

Mathieu
(*) This is the only remarks I had about openjpeg. It assumes JPEG 
stream is continuous, which is not always true for us. As a side note, 
Jasper made also the same assumption.

Julien Jomier wrote:
> Hi Math,
> 
> Will the new library replace the current itkjpeg or does it just provide 
> support for JPEG2000?
> 
> What amount of disk space is involved (source only)?
> I think we are always in favor of adding new IO libraries in ITK as long 
> as:
>   a) it doesn't take too much disk space
>   b) it's easy to maintain
> 
> Since you are using it in GDCM I guess (b) is not a problem.
> 
> Another option is to add an option in CMake to use the library externally.
> 
> my two cents,
> 
> Julien
> 
> Mathieu Malaterre wrote:
> 
>> Hello,
>>
>>     I have a minor technical issue. Currently GDCM uses the 
>> (patched)jpeg from the Utilities directory to be able to decompress 
>> JPEG lossy and lossless file. I was asked to update gdcm 1.0 to gdcm 
>> 1.2. In gdcm 1.2 we have added support for JPEG2000 encoded file. This 
>> is for now very rare IMHO. So my question is:
>>
>> - Do I add support for JPEG2000 in ITK, knowing that it will add a new 
>> library to ITK (~373k line of code). Code for the library can be found 
>> at http://www.openjpeg.org (*)
>>
>> - If yes, do I make it an available library just like png or tiff, or 
>> do I keep it encapsulated into GDCM ?
>>
>> - If not I can still update to gdcm 1.2 which will still add a lot of 
>> new features lacking in gdcm 1.0. I'll simply change the 
>> cmakelists.txt to not include JPEG2000 code.
>>
>> Comments welcome,
>> Mathieu
>> (*) At some point during the development process jasper was considered 
>> and used in GDCM to decompress JPEG2000 DICOM image. But due to a 
>> major decompression problem for 16bits lossless image the support was 
>> discontinued in favor of the lighter openjpeg implementation from 
>> Communications and Remote Sensing Lab (TELE).
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>>
> 
>