Realtime Head-Tracking for Adjusting Head Position

This program is designed to capture head position information from the CTF MEG system and display a scalp surface relative to the sensor helmet. The acquisition workstation runs the FieldTrip program acq2ftx and a second computer runs Brainstorm and the FieldTrip buffer program. The acquisition workstation and the second computer need to be connected to each other either across the same network or a direct computer-to-computer network connection.

System Setup:

On the second computer, Brainstorm and Fieldtrip should be installed in the same location.

On the MEG acquisition workstation, acq2ftx should be installed. Please see http://fieldtrip.fcdonders.nl/development/realtime for more information about the realtime FieldTrip buffer.

How to use:

On the second computer, start Brainstorm

Start Brainstorm Headtracking Program

• In the Matlab command window type bst_headtracking(<hostIP>,<TCPIP>) where <hostIP> is the IP address of the acquisition workstation and <TCPIP> is the TCP/IP port (typically 1972).

• When prompted, select the POS file (headshape points file) corresponding to the current subject
• The headpoints will be added, click OK

• Wait for the prompt: BST> Waiting for acquisition to start...

Start ACQ Headtracking

• On the acquisition workstation, select a protocol that includes Continuous Head Localization or enable the functionality in the current protocol (Settings > Channel Settings > Localization > continuous)

• Start the ACQ Headtracking program from a terminal (see the FieldTrip documentation for more information about running this application).

example:

acq2ftx '10.0.0.2’:1972:RE:1:HLC0011,HLC0012,HLC0013, ... HLC0021,HLC0022,HLC0023,HLC0031,HLC0032,HLC0033

where 10.0.0.2 should be the IP address of the second computer.

• Wait for the program to start. The following is displayed in the terminal window when ready:
• Start the acquisition. Do not localize the head or begin recording during the head tracking.
• A Brainstorm figure will appear on the second computer. Adjust subject as needed.

To Stop the ACQ Headtracking Program:

• Close the Brainstorm Figure (second computer)
• Abort data acquisition (ACQ workstation)
• Close the ACQ Headtracking terminal (ACQ workstation)