Interfacing with Matlab and Octave

Thanks to the REST API of Orthanc, it is easy to access DICOM images from Matlab or Octave, as depicted in the following sample image:

Both Matlab and Octave have access to HTTP servers thanks to their built-in urlread() function. Once must simply install a Matlab/Octave library to decode JSON files. The JSONLab toolkit works perfectly to this end.

Using JSONlab, the following code will download and display a DICOM image:

SERIES = 'ae164c84-e5bd0366-ba937a6d-65414092-f294d6b6';
URL = 'https://orthanc.uclouvain.be/demo/';

# Get information about the instances in this DICOM series
instances = loadjson(urlread([ URL '/series/' SERIES '/instances' ]));

# Select one slice from the series
instance = instances{1}.ID

# Decode the slice with Orthanc thanks to the "/matlab" URI
slice = eval(urlread([ URL '/instances/' instance '/matlab' ]));

# Compute the maximum value in this slice
max(max(slice))

# Display the slice
imagesc(slice)

# Annotate the graph with the patient name and ID
tags = loadjson(urlread([ URL '/instances/' instance '/tags?simplify' ]));
title([ 'This is a slice from patient ' tags.PatientID ' (' tags.PatientName ')' ])

Opening the raw DICOM file

Here is another sample Matlab/Octave script explaining how to download the raw DICOM file corresponding to one given instance stored in Orthanc, then decode this DICOM file using Matlab/Octave:

SERIES = 'ae164c84-e5bd0366-ba937a6d-65414092-f294d6b6';
URL = 'https://orthanc.uclouvain.be/demo/';

# Get information about the instances in this DICOM series
instances = loadjson(urlread([ URL '/series/' SERIES '/instances' ]));

# Select one slice from the series
instance = instances{1}.ID

# Download the raw DICOM file and store it as a file named "instance.dcm"
urlwrite([ URL '/instances/' instance '/file' ], 'instance.dcm');

if exist('OCTAVE_VERSION', 'builtin') ~= 0
  # If running Octave instead of Matlab, load the "dicom" package from Octave Forge
  pkg load image
  pkg load dicom
endif

# Decode the downloaded DICOM file
im = dicomread('instance.dcm');
imagesc(im)

Note: If running Octave, you will have to manually install the dicom package from Octave Forge. Download the source code of the package, make sure the libgdcm2-dev and octave-image packages are installed (for Ubuntu 16.04), then type the following command to install the dicom package:

$ octave --no-gui --eval "pkg install ./dicom-0.2.0.tar.gz"