Dicom package

At an early development stage. octave-forge svn

• Maintainer: Andy Buckle [1]
• Currently worked on by: Kris Thielemans

Supporting library

GCDM. You can usually get this via your package manager,e e.g. on Ubuntu

sudo apt-get install libgdcm2.0

Alternatively, build it yourself. Get the source with subversion.

svn co https://gdcm.svn.sourceforge.net/svnroot/gdcm/branches/gdcm-2-0

cmake and g++ are required. create a gdcmbin directory parallel to the gdcm-2-0 directory. Change to gdcmbin and then run cmake (Linux/cygwin).

> mkdir gdcmbin
> ls
gdcmbin gdcm-2-0
> cd gdcmbin
> cmake -DGDCM_BUILD_SHARED_LIBS=ON ../gdcm-2-0/

This creates a Makefile in your gdcmbin directory. You can easily edit cmake options with "make edit_cache", for example to build applications like gdcmdump. "make help" is also very useful.

make install

On my system, I also had to add this to my ~/.bashrc.

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib

Mingw32 is similar. Get openSSL: Win32 Openssl v1.0.0a Light

cmake -G "MinGW Makefile" -DGDCM_BUILD_SHARED_LIBS=ON ..\gdcm-2-0
mingw32-make all

Features

All of these still need work, but they exist, and are usable to some extent.

• dicomdict (load different dict - file follows same format as Matlab's)
• dicominfo (load metadata into octave struct. possible bug in SQ loading)
• dicomlookup (keyword <-> tag)
• dicomread (load pixel data, 2D or 3D int types. Does not yield colormaps, yet.)

Todo

• dicomanon
• dicomuid
• dicomwrite
• isdicom

Questions

I don't have a Matlab license available. I would like to make this package compatible with the dicom functions in Matlab's image processing toolbox, as far as possible.

• Octave (and Matlab) stores images (y,x) and DICOM is intrinsically (x,y). Does Matlab transpose images when it loads them?
  • matlab reads the data from the dicom file as if it's a raw block of numbers (and then converts if necessary). We think that current Octave/dicom behaviour is compatible with matlab.
• I would like people to try m-files that worked with Matlab to let me know of problems.
• (not necessarily) Matlab related: I need examples of odd DICOM files. I have plenty with complex metadata, but I need some with unusual images.
  • More than one sample per pixel
  • Colour
  • Float types
• DA (date) VR: does Matlab turn them into a string?
• if the user supplies metadata (eg HighBit?, BitsStored?) that describe the type of the pixels and this is not in agreement with the type of the image matrix supplied, does Matlab
  • silently convert the image pixel type to match the metadata?
  • silently convert the metadata to match the pixel type?
  • error and do nothing?
• What does dicominfo do when a tag is not in its dictionary. Answer: assign to a field like Private_3243_0010 (as Matlab)
• dicominfo: Items in sequences are not necessarily the same, so are stored as nested structs like dcm.RTDoseROISequence?.Item_1.DoseUnits?(as Matlab)