Ultrasound acquisition

The Phonology Lab has a SonixTablet system from Ultrasonix for performing ultrasound studies. Consult with Susan Lin for permission to use this system.

Data acquisition workflow

The standard way to acquire ultrasound data is to run an Opensesame experiment on a data acquisition computer that communicates with the ultrasound system and saves timestamped data and metadata for each acquisition. The first step in the process is to create the experiment, at which point you will be ready to run your experiment.

Prepare the experiment

The first step is to prepare your experiment. You will need to create an Opensesame script with a series of speaking prompts and data acquisition commands. In simple situations you can simply edit a few variables in our sample script and be ready to go.

Run the experiment

These are the steps when you are ready to run your experiment:

Start the ultrasound system

1. Turn on the ultrasound system's power supply, found on the floor beneath the system.
2. Turn on the ultrasound system with the pushbutton on the left side of the machine.
3. Start the Sonix RP software.

Start the data acquisition system

1. Turn on the data acquisition computer next to the ultrasound system and use the LingGuest account.
2. Check your hardware connections and settings:
   1. The Steinberg USB audio device should be connected to the data acquisition computer.
   2. The subject microphone should be connected to 'Mic/Line 1' of the audio device. Use the patch panel if your subject will be in the soundbooth.
   3. Make sure the '+48V' switch on the back of the audio device is set to 'On' if you are using a condenser mic (usually recommended).
   4. Make a test audio recording of your subject and adjust the audio device's 'Input 1 Gain' setting as needed.
   5. The synchronization signal cable should be connected to the BNC connector labelled '25' on the ultrasound system, and the other end should be connected to 'Mic/Line 2' of the audio device.
   6. The audio device's 'Input 2 Hi-Z' button should be selected (pressed in).
   7. The audio device's 'Input 2 Gain' setting should be at the dial's midpoint.
3. Open and run your Opensesame experiment.

Postprocessing

Each acquisition resides in its own timestamped directory. If you follow the normal Opensesame script conventions these directories are created in per-subject subdirectories of your base data directory. Normal output includes a .bpr file containing ultrasound image data, a .wav containing speech data and the ultrasound synchronization signal, and a .idx.txt file containing the frame indexes of each frame of data in the .bpr file.

Troubleshooting

Early versions of ultracomm and ultrasession.py had issues with occasional hangs when run in an Opensesame experiment. These problems are believed to have been resolved as of the Summer 2015 0.2.1-alpha release of ultracomm when used with an up-to-date ultrasession.py and following the inline scripts used in the sample experiment. Nevertheless, it is good form to check for instances of sox and ultracomm that continue to run after your experiment has concluded, as they may continue to write data to disk until they are terminated. To do this press Ctrl-Alt-Delete and open the Task Manager. Check the Processes tab for instances of sox.exe and ultracomm.exe and use the End Process button to terminate these programs if they are present.

A known issue is that the ultrasound system sometimes starts imaging but never sends data to the acquisition computer. This situation occurs in about 1% of acquisitions and results in empty .bpr and .bpr.idx.txt files.