Overlays in Multi-frame True Color SC Image

[Martin Bauer]

Hello!

I tried to convert a Multi-frame True Color SC Image with the help of DCMTK into a Bitmap. Within the image there is an Overlay Plane Module. But the resulting image is stored as bitmap without the overlay information. I also tried to activate the Overlays through ->showAllOverlays(0) and ->showAllOverlays(1)

The return value of this functions is 0 --> related to the documentation this means that an error occured.

here is the code:

initCodecs(); // initialize JPEG and so on

DicomImage* diImage = new DicomImage("document.dcm");

std::cout << diImage->showAllOverlays(0) << std::endl;
std::cout << diImage->showAllOverlays(1) << std::endl;
diImage->writeBMP("document.bmp");

I even searched for more information in the the DICOM standard (2009) which, acording to chapter A.8.1 and A.8.5.3 in part 3, allows overlay planes in secondary capture files.

further on i analysed the method showAllOverlays() which calls getOverlayPtr() which is a virtual method from the diimage.h and just overwritten in the dimoimg.h there is also the comment in diimage.h -
/** get pointer to the object managing the overlay planes
*
** #param idx index of overlay group (here: not used, since only applicable for monochrome images)
*
** @return pointer to the overlay managing object, here: NULL
*/
virtual DiOverlay *getOverlayPtr(const unsigned int /*idx*/)
{
return NULL;
}

So maybe you could inform me if and when there will be support for overlays in color images.

with best regards
Martin

[Jörg Riesmeier]

So maybe you could inform me if and when there will be support for overlays in color images.

The DicomImage class does not support overlays in color images. This should be clear from the documentation: "only applicable to grayscale images"

Btw, this additional requirement is already on our list of things to do (sometime) but with low priority.

I even searched for more information in the the DICOM standard (2009) which, acording to chapter A.8.1 and A.8.5.3 in part 3, allows overlay planes in secondary capture files.

Hmm, I read the following in section A.8.5.4 of PS 3.3-2009:

The Overlay module shall not be present.

I guess you are referring to the "old" Secondary Capture Image IOD ...

[Martin Bauer]

Thanks for the fast reply!

This makes the situation much clearer for me.

With best regards
Martin