OMERO MATLAB language bindings

See Developing OMERO clients and OME-Remote Objects, for an introduction to Object.

Installing the OMERO.matlab toolbox

  • Download the latest released version from the download page.
  • Unzip the directory anywhere on your system.
  • In MATLAB, move to the newly unzipped directory and run loadOmero;.
  • The MATLAB files are now on your path, and the necessary jars are on your java classpath. You can change directories and still have access to OMERO.

Once OMERO.matlab is installed, the typical workflow is:

  1. Creating a connection
  2. Keeping your session alive
  3. Creating an unencrypted session (optional)
  4. Do some work (load objects, work with them, upload to the server…)
  5. Closing your connection
  6. Unloading OMERO (optional)

As a quickstart example, the following lines create a secure connection to a server, read a series of images and close the connection.

client = loadOmero(servername, port);
session = client.createSession(user, password);
images = getImages(session, ids);

Examples of usage of the OMERO.matlab toolbox are provided in the training examples directory.

Configuring the OMERO.matlab connection

Creating a connection

As described under Working with OMERO, there are several ways to configure your connection to an OMERO server. OMERO.matlab comes with a few conveniences for making this work.

If you run client = loadOmero(); (i.e. loadOmero with an output argument), then OMERO.matlab will try to configure the omero.client object for you. First, it checks the ICE_CONFIG environment variable. If set, it will let the omero.client constructor initialize itself. Otherwise, it looks for the file ice.config in the current directory. The OMERO.matlab toolbox comes with a default ice.config file pointing at localhost. To use this configuration file, you should replace localhost by your server address.

Alternatively, you can pass the same parameters to loadOmero; that you would pass to omero.client:

>> omero_client_1 = loadOmero('localhost');
>> omero_client_2 = omero.client('localhost');

Or, if you want a session created directly, the following are equivalent:

>> [client1, session1] = loadOmero('localhost');
>> client2 = loadOmero('localhost');
>> session2 = client2.createSession()

Keeping your session alive

For executing any long running task, you will need a background thread which keeps your session alive. If you are familiar with MATLAB Timers you can use omeroKeepAlive.m directly or modify it to your liking.

>> [c,s] = loadOmero;
>> t = omeroKeepAlive(c); % Create a 60-second timer and starts it
>>>> delete(t);             % Disable the keep-alive

Alternatively, you can use the Java-based enableKeepAlive method, but it is not configurable from within MATLAB:

c.enableKeepAlive(60); % Call session.keepAlive() every 60 seconds
c.closeSession();      % Close session to end the keep-alive

Creating an unencrypted session

Once a session has been created, if you want to speed up the data transfer, you can create and use an unencrypted session as:

unsecureClient = client.createClient(false);
sessionUnencrypted = unsecureClient.getSession();

Closing your connection

When you are done with OMERO, it is critical that you close your connection to save resources:

clear client1;
clear session1;

If you created an unencrypted session, you will need to close the unsecure session as well:


Unloading OMERO

Then if you would like, you can unload OMERO as well:


You may see the following warning when unloading OMERO:

>> unloadOmero()
Warning: Objects of omero/client class exist - not clearing java
> In javaclasspath>doclear at 377
  In javaclasspath>local_javapath at 194
  In javaclasspath at 105
  In javarmpath at 48
  In unloadOmero at 75

While unloading OMERO, found java objects left in workspace.
Please remove with 'clear <name>' and then run 'unloadOmero'
again.  Printing all objects...

  Name      Size            Bytes  Class           Attributes

  c         1x1                    omero.client

Closing session(s) for 1 found client(s): c

This means that there is still an OMERO.matlab object in your workspace. If not listed, use whos to find such objects, and clear to remove them. After that, run unloadOmero() again:

>> clear c
>> unloadOmero()


You should also unload OMERO before installing a new version of OMERO.matlab or calling loadOmero again.

If you need to create another session without unloading/loading OMERO again, use the omero.client object directly:

>> [c,s] = loadOmero(arg1,arg2);
>> c = omero.client(arg3,arg4);
>> s = c.createSession();

Reading data

The IContainer service provides methods to load the data management hierarchy in OMERO – projects, datasets… A list of examples follows indicating how to load projects, datasets, screens…

  • Projects

The projects owned by the user currently logged in can be retrieved using the getProjects function:

projects = getProjects(session)

If the project identifiers are known, they can be specified as:

projects = getProjects(session, ids)

If the projects contain datasets, the datasets will automatically be loaded:

for j = 1 : numel(projects)
    datasetsList = projects(j).linkedDatasetList;
    for i = 0:datasetsList.size()-1,
        d = datasetsList.get(i);

If the datasets contain images, the images will automatically be loaded:

imageList = projects(1).linkedDatasetList.get(0).linkedImageList;

To avoid loading the whole graph (projects, datasets, images), pass false as a second optional argument. Only datasets will be loaded:

unloadedProjects = getProjects(session, ids, false)

To return the orphaned datasets as well as the projects, you can query the second output argument of getProjects:

[projects, orphanedDatasets] = getProjects(session)
[unloadedProjects, unloadedOrphanedDatasets] = getProjects(session, [], false)
  • Datasets

The datasets owned by the user currently logged in can be retrieved using the getDatasets function:

datasets = getDatasets(session)

If the dataset identifiers are known, they can be specified as:

datasets = getDatasets(session, ids)

If the datasets contain images, the images will automatically be loaded:

imageList = datasets(1).linkedImageList;

To avoid loading the images, pass false as a second optional argument:

unloadedDatasets = getDatasets(session, ids, false)
  • Images

All the images owned by the user currently logged in can be retrieved using the getImages function:

images = getImages(session)

If the image identifiers are known, they can be specified as:

images = getImages(session, ids)

All the images contained in a subset of datasets of known identifiers datasetsIds can be returned using:

datasetImages = getImages(session, 'dataset', datasetsIds)

All the images contained in all the datasets under a subset of projects of known identifiers projectIds can be returned using:

projectImages = getImages(session, 'project', projectIds)

The Image-Pixels model implies you need to use the Pixels objects to access valuable data about the Image:

pixels = image.getPrimaryPixels();
sizeZ = pixels.getSizeZ().getValue(); % The number of z-sections.
sizeT = pixels.getSizeT().getValue(); % The number of timepoints.
sizeC = pixels.getSizeC().getValue(); % The number of channels.
sizeX = pixels.getSizeX().getValue(); % The number of pixels along the X-axis.
sizeY = pixels.getSizeY().getValue(); % The number of pixels along the Y-axis.
  • Screens

The screens owned by the user currently logged in can be retrieved using the getScreens function:

screens = getScreens(session)

If the screen identifiers are known, they can be specified as:

screens = getScreens(session, ids)

Note that the wells are not loaded. The plate objects can be accessed using:

for j = 1 : numel(screens),
platesList = screens(j).linkedPlateList;
for i = 0:platesList.size()-1,
    plate = platesList.get(i);
    plateAcquisitionList = plate.copyPlateAcquisitions();
    for k = 0:plateAcquisitionList.size()-1,
        pa = plateAcquisitionList.get(i);

To return the orphaned plates as well as the screens, you can query the second output argument of getScreens:

[screens, orphanedPlates] = getScreens(session)
[unloadedScreens, unloadedOrphanedPlates] = getScreens(session, [], false)
  • Plates

The plates owned by the user currently logged in can be retrieved using the getPlates function:

plates = getPlates(session)

If the plate identifiers are known, they can be specified as:

plates = getPlates(session, ids)
  • Wells

Given a plate identifier, the wells can be loaded using the findAllByQuery method:

wellList = session.getQueryService().findAllByQuery(
['select well from Well as well '...
'left outer join fetch well.plate as pt '...
'left outer join fetch well.wellSamples as ws '...
'left outer join fetch ws.plateAcquisition as pa '...
'left outer join fetch ws.image as img '...
'left outer join fetch img.pixels as pix '...
'left outer join fetch pix.pixelsType as pt '...
'where = ', num2str(plateId)], []);
for j = 0:wellList.size()-1,
    well = wellList.get(j);
    wellsSampleList = well.copyWellSamples();
    for i = 0:wellsSampleList.size()-1,
        ws = wellsSampleList.get(i);
        pa = ws.getPlateAcquisition();

Raw data access

You can retrieve data, plane by plane or retrieve a stack.

  • Plane

The plane of an input image at coordinates (z, c, t) can be retrieved using the getPlane function:

plane = getPlane(session, image, z, c, t);

Alternatively, the image identifier can be passed to the function:

plane = getPlane(session, imageID, z, c, t);
  • Tile

The tile of an input image at coordinates (z, c, t) originated at (x, y) and of dimensions (w, h) can be retrieved using the getTile function:

tile = getTile(session, image, z, c, t, x, y, w, h);

Alternatively, the image identifier can be passed to the function:

tile = getTile(session, imageID, z, c, t, x, y, w, h);
  • Stack

The stack of an input image at coordinates (c, t) can be retrieved using the getStack function:

stack = getStack(session, image, c, t);

Alternatively, the image identifier can be passed to the function:

stack = getStack(session, imageID, c, t);
  • Hypercube

This is useful when you need the Pixels intensity.

% Create the store to load the stack. No access via the gateway
store = session.createRawPixelsStore();
% Indicate the pixels set you are working on
store.setPixelsId(pixelsId, false);

% Offset values in each dimension XYZCT
offset = java.util.ArrayList;

size = java.util.ArrayList;

% Indicate the step in each direction,
% step = 1, will return values at index 0, 1, 2.
% step = 2, values at index 0, 2, 4…
step = java.util.ArrayList;
% Retrieve the data
store.getHypercube(offset, size, step);
% Close the store


The following table lists all OMERO.matlab functions used to manipulate annotations from OMERO:

  Tag File Comment XML
Get by identifier getTagAnnotations getFileAnnotations getCommentAnnotations getXmlAnnotations
Linked to images getImageTagAnnotations getImageFileAnnotations getImageCommentAnnotations getImageXmlAnnotations
Linked to datasets getDatasetTagAnnotations getDatasetFileAnnotations getDatasetCommentAnnotations getDatasetXmlAnnotations
Linked to projects getProjectTagAnnotations getProjectFileAnnotations getProjectCommentAnnotations getProjectXmlAnnotations
Linked to screens getScreenTagAnnotations getScreenFileAnnotations getScreenCommentAnnotations getScreenXmlAnnotations
Linked to plates getPlateTagAnnotations getPlateFileAnnotations getPlateCommentAnnotations getPlateXmlAnnotations
Write writeTagAnnotation writeFileAnnotation writeCommentAnnotation writeXmlAnnotation
  • Reading annotations

If the identifier of the annotation of a given type is known, the annotation can be retrieved from the server using the corresponding function, e.g. for tags using the getTagAnnotations function:

tagAnnotations = getTagAnnotations(session, tagIds);

Alternatively, the annotations of a given type linked to a given object can be retrieved using the corresponding function, e.g. to retrieve all tags linked to images getImageTagAnnotations function:

tagAnnotations = getImageTagAnnotations(session, imageIds);

Annotations can be filtered by namespace. To include only annotations with a given namespace ns, use the include parameter/key value:

tagAnnotations = getImageTagAnnotations(session, imageIds, 'include', ns);

To exclude all annotations with a given namespace ns, use the exclude parameter/key value:

tagAnnotations = getImageTagAnnotations(session, imageIds, 'exclude', ns);

By default, only the annotations owned by the session owner are returned. To specify the owner of the annotations, use the owner paramter/key value pair. For instance to return all tag annotations owned by user 5:

tagAnnotations = getImageTagAnnotations(session, imageIds, 'owner', 5);

To retrieve all annotations independently of their owner, use -1 as the owner identifier:

tagAnnotations = getImageTagAnnotations(session, imageIds, 'owner', -1);
  • Reading file annotations

The content of a file annotation can be downloaded to local disk using the getFileAnnotationContent function. If the file annotation has been retrieved from the server as fileAnnotation, then the content of its OriginalFile can be downloaded under target_file using:

getFileAnnotationContent(session, fileAnnotation, target_file);

Alternatively, if only the identifier of the file annotation faId is known:

getFileAnnotationContent(session, faId, target_file);
  • Writing annotations

New annotations can be created using the corresponding write*Annotation function (see table above). Existing annotations can be linked to existing objects on the server using the linkAnnotation function.

For example, to create a new tag annotation tag_name and attach it to the image image_id:

tagAnnotation = writeTagAnnotation(session, tag_name);
link = linkAnnotation(session, tagAnnotation, 'image', image_id);

To create a file annotations from the content of a local_file_path and attach it to the image image_id:

fileAnnotation = writeFileAnnotation(session, local_file_path);
link = linkAnnotation(session, fileAnnotation, 'image', image_id);

For existing file annotations, it is possible to replace the content of the original file without having to recreate a new file annotation using the updateFileAnnotation function. If the file annotation has been retrieved from the server as fileAnnotation, then the content of its OriginalFile can be replaced by the content of local_file_path using:

updateFileAnnotation(session, fileAnnotation, local_file_path);

Writing data

  • Create a Dataset and link it to an existing project.
dataset = omero.model.DatasetI;
dataset.setName(omero.rtypes.rstring(char('name dataset')));
dataset.setDescription(omero.rtypes.rstring(char('description dataset')));

% Link Dataset and Project

link = omero.model.ProjectDatasetLinkI;
link.setParent(omero.model.ProjectI(projectId, false));


How to use OMERO tables

  • Create a table. In the following example, a table is created with 2 columns.
name = char(java.util.UUID.randomUUID());
columns = javaArray('omero.grid.Column', 2)
columns(1) = omero.grid.LongColumn('Uid', 'testLong', []);
valuesString = javaArray('java.lang.String', 1);
columns(2) = omero.grid.StringColumn('MyStringColumn', '', 64, valuesString);

% Create a new table.
table = session.sharedResources().newTable(1, name);

% Initialize the table
% Add data to the table.
data = javaArray('omero.grid.Column', 2);
data(1) = omero.grid.LongColumn('Uid', 'test Long', [2]);
valuesString = javaArray('java.lang.String', 1);
valuesString(1) = java.lang.String('add');
data(2) = omero.grid.StringColumn('MyStringColumn', '', 64, valuesString);
file = table.getOriginalFile(); % if you need to interact with the table
  • Read the contents of the table.
of = omero.model.OriginalFileI(file.getId(), false);
tablePrx = session.sharedResources().openTable(of);

% Read headers
headers = tablePrx.getHeaders();
for i=1:size(headers, 1),
    headers(i).name; % name of the header
    % Do something

% Depending on the size of table, you may only want to read some blocks.
cols = [0:size(headers, 1)-1]; % The number of columns you wish to read.
rows = [0:tablePrx.getNumberOfRows()-1]; % The number of rows you wish to read.
data = tablePrx.slice(cols, rows); % Read the data.
c = data.columns;
for i=1:size(c),
    column = c(i);
    % Do something
tablePrx.close(); % Important to close when done.


To learn about the model, see the developers guide to the ROI model. Note that annotations can be linked to ROI.

  • Creating ROI

This example creates a ROI with two shapes, a rectangle and an ellipse, and attaches it to an image:

% First create a rectangular shape.
rectangle = createRectangle(0, 0, 10, 20);
% Indicate on which plane to attach the shape
setShapeCoordinates(rectangle, 0, 0, 0);

% First create an ellipse shape.
ellipse = createEllipse(0, 0, 10, 20);
% Indicate on which plane to attach the shape
setShapeCoordinates(ellipse, 0, 0, 0);

% Create the roi.
roi = omero.model.RoiI;
% Attach the shapes to the roi, several shapes can be added.

% Link the roi and the image
roi.setImage(omero.model.ImageI(imageId, false));
% Save
iUpdate = session.getUpdateService();
roi = iUpdate.saveAndReturnObject(roi);
% Check that the shape has been added.
numShapes = roi.sizeOfShapes;
for ns = 1:numShapes
   shape = roi.getShape(ns-1);

See also

ROI utility functions
OMERO.matlab functions for creating and managing Shape and ROI objects.
  • Retrieving ROIs linked to an image
service = session.getRoiService();
roiResult = service.findByImage(imageId, []);
rois = roiResult.rois;
n = rois.size;
shapeType = '';
for thisROI  = 1:n
    roi = rois.get(thisROI-1);
    numShapes = roi.sizeOfShapes;
    for ns = 1:numShapes
        shape = roi.getShape(ns-1);
        if (isa(shape, 'omero.model.Rect'))
           rectangle = shape;
        elseif (isa(shape, 'omero.model.Ellipse'))
           ellipse = shape;
        elseif (isa(shape, 'omero.model.Point'))
           point = shape;
        elseif (isa(shape, 'omero.model.Line'))
           line = shape;
  • Removing a shape from ROI
// Retrieve the roi linked to an image
service = session.getRoiService();
roiResult = service.findByImage(imageId, []);
n = rois.size;
for thisROI  = 1:n
    roi = rois.get(thisROI-1);
    numShapes = roi.sizeOfShapes;
    for ns = 1:numShapes
        shape = roi.getShape(ns-1);
        % Remove the shape
    % Update the roi.
    roi = iUpdate.saveAndReturnObject(roi);

Deleting data

It is possible to delete projects, datasets, images, ROIs… and objects linked to them depending on the specified options (see Deleting in OMERO). For example, images of known identifiers can be deleted from the server using the deleteImages function:

deleteImages(session, imageIds);

See also

deleteProjects, deleteDatasets, deleteScreens, deletePlates
Utility functions to delete objects

Rendering images

The RenderImages.m example script shows how to initialize the rendering engine and render an image.

Creating Image

The CreateImage.m example script shows how to create an image in OMERO. A similar approach can be applied when uploading an image. To upload individual planes onto the server, the data must be converted into a byte (int8) array first. If the Pixels object has been created, this conversion can done using the toByteArray function.