OpenIGTLink/ProtocolV2/Trial

<< OpenIGTLink

About this page

This page describes how to try new features in OpenIGTLink Protocol Version 2 before its release in early 2011.

OpenIGTLink library with Version 2 features

The library for protocol version 2 is available from the OpenIGTLink repository (see library version 2 information). To build the library with version 2 features, please follow the instruction bellow:

0. Create a working directory and go to the directory.

1. Obtain the source code from the repository. If you are using command line tools from a UNIX/Linux terminal:

svn co http://svn.na-mic.org/NAMICSandBox/trunk/OpenIGTLink

2. Create a build directory and move into it. From the terminal:

mkdir OpenIGTLink-build
cd OpenIGTLink-build

3. Run CMake. Please make sure to turn on BUILD_EXAMPLES and OpenIGTLink_PROTOCOL_VERSION_2 options. From the terminal, run:

cmake -DBUILD_EXAMPLES:BOOL=ON -DOpenIGTLink_PROTOCOL_VERSION_2:BOOL=ON ../OpenIGTLink

4. Build the library. From the terminal, just run make command:

make

5. You can find the binary files including example programs in 'OpenIGTLink-build/bin' directory (or 'OpenIGTLink-build/bin/{Debug or Release}' on Windows).

Trying Protocol Version 2 with 3D Slicer

The latest 3D Slicer 3.6.3 beta (downloaded after Nov 19, 2010) can handle a part of newly introduced features in version 2. You can either build 3D Slicer on your machine or obtain a nightly build from Slicer Download Page. If you download a nightly build, please make sure to download a binary built after Nov 19.

Before you try...

Before you try the following sections, you may check if the 3D Slicer is actually built upon OpenIGTLink Library Version 2 as follows: open OpenIGTLinkIF module, create and configure a connector as a server in the "Connector" frame; once the connector is created, open the DATA I/O Configuration frame and right-click the connector (shown as vtkMRMLIGTLConnectorNode1, unless you change the connector name). If you see the pull-down menu as shown in the following image, the 3D Slicer is built upon the version 2 library and ready to try.

New tracking data message with flow control

Version 2 protocol defines a new tracking data message, that not only conveys transforms, but also some information about tracking instrument.

First, open a terminal and run TrackingDataServer, which comes as an example in OpenIGTLink (see the previous section), as follows:

cd <OpenIGTLink build directory>/bin
./TrackingDataServer 18944

Then launch 3D Slicer, open OpenIGTLinkIF module and create an client connector in Connectors frame (see the figure left bellow). After clicking the Active check box, the OpenIGTLinkIF module starts connecting to the server. If successful, the status column shows ON.

On the terminal, you can also verify that 3D Slicer OpenIGTLinkIF module is connected to the server.

A client is connected.

Next step is to request tracking data from the server program. In 3D Slicer OpenIGTLinkIF module, open Data I/O Configurations and right-click the connector ('vtkMRMLIGTLConnectorNode1' in default) to show the pull-down menu. Once you choose Open tracking control window... from the pull down menu, Tracking control window pops up on the screen (see the right screenshot bellow).

To request for the tracking data, click Start tracking button on the tracking control window. If the request is received successfully by the server, it shows the following message on the terminal and start sending tracking data.

Received a STT_TDATA message.
Interval = 50 (ms)

The server sends 3-channel transform data, which are stored in three linear transform nodes named Channel 0, Channel 1 and Channel 2. To visualize them, Open Visualization/Slice Control frame in OpenIGTLinkIF module, choose one of Channel 0 - Channel 2 from Locator source and click Show Locator check box.

The server stop sending the tracking data, after you click Stop tracking button on the tracking control window. Please make sure to disconnect 3D Slicer from the server by clicking Active check box in Connectors frame of OpenIGTLinkIF module.