Lab Streaming Layer (LSL)
Notes on the data
Motion
Motion can be found in the menu on the left-hand side of the EmotivPRO screen.
The Motion tab displays the motion sensor data. Motion sensor data shows your headset’s position and orientation using a combination of absolute orientation (magnetometer), acceleration (accelerometer), and rotation vectors (quaternion) data in a ten-channel time series graph.
Please note: EPOC Flex does not support motion sensor data.

3D visualization

You can choose to view a 3D visualization of the motion sensor represented by a cube. The cube represents accurate rotation of the device along the X, Y and Z axes.
To calibrate the cube, turn your headset on and click the Calibrate button—this sets the cube to position 0.
The mirrored display is automatically selected so that the pink marker points towards you when your headset is worn correctly. If the mirrored option is not selected, the pink pointer will face away from you and the blue marker will point towards you.

Rotation, roll, and pitch of the cube

Rotation The rotation gauge represents the cube’s rotation along the Y axis (also known as pointing direction). Position 0 is set with the arrow in a vertical position on the gauge.
Roll The roll gauge represents the cube’s rotation along the Z axis. It can also be described as roll left or roll right. The pink and blue dots on the gauge stay in the fixed position. Position 0 is set in a horizontal position on the gauge.
Pitch The pitch gauge represents the cube’s rotation along the X axis. It can also be described as tilt up or tilt down. Position 0 is set in a horizontal position on the gauge.
Please note: For older EPOC+ headsets, (Firmware <0x633) motion sensors display data concerning your headset's position and orientation using a (gyroscope), acceleration (accelerometer) and absolute orientation (magnetometer) measurements.

Motion sensor graph

The motion tab window shows a graph of the connected headsets' various measured outputs. All headsets manufactured since 2018 feature the same 9-axis inertial measuring unit the invensense ICM-20948. We chose this part because it has sensor fusion processing where the various sensors are measured and rotational vectors called quaternions (Q0-Q3) are calculated so it is easier for understanding head movement. We have also included the raw outputs from the accelerometer and magnetometer. The only exception is MN8 which does not have a magnetometer.
Older headsets (EPOC+ / INSIGHT 2015-2018) are still supported but output raw 9-axis data for acceleration, gyroscope and magnetometer which researchers will need to post-process. Original EPOC devices are also supported but only feature gyroscope X and Y channels.
The outputs shown on the window are also exported in the same order. They are:
  • Quaternion 0, 1, 2, 3 - rotational vector representation of head position.
  • AccX, AccY, AccZ - acceleration in X, Y, Z directions.
  • MagX, MagY and MagZ - magnetometer in X, Y and Z directions
  • GyroX, GyroY and GyroZ - gyroscope in X, Y and Z directions (Only older headsets have this output.
The resolution of motion sensor data for EPOC is 128 Hz and 12-bits, and for Insight headsets is 64 Hz and 14-bits. The resolution for EPOC+ and EPOC X is 16-bits and can be 32, or 64 (or OFF) depending on the headset’s configuration and whether or not it is connected via Bluetooth. When EPOC+ or EPOC X is connected to EmotivPRO via Bluetooth, the rate is limited to 64 Hz. For EPOC Flex, the resolution of motion sensor data is 8 bits and the sampling rate is 16 Hz. Epoc headsets include GyroX and GyroY sensors only. Y-axis is samples.
Motion data resolution
EPOC - 128 Hz and 12-bits. Insight - 64 Hz and 14-bits. EPOC+ and EPOC X - 16-bits (but it can be 32 or 64 (or OFF)) depending on the headset’s configuration and whether or not it is connected via Bluetooth. When EPOC+ or EPOC X is connected to EmotivPRO via Bluetooth, the rate is limited to 64 Hz. EPOC Flex - 16 Hz and 8-bits.

How to turn channels on and off

You can turn individual channels on and off in the motion sensor view to focus on the data you are most interested in. To do this:
  1. 1.
    Click on the eye icon at the top-right-hand corner of the screen.
  2. 2.
    A pop-up box will open showing the channels you can select.
  3. 3.
    Select the channels that you want to see
  4. 4.
    To close the pop-up box, click anywhere outside of the box.

How to toggle all channels on and off

The toggle feature allows you to see all or none of the channels.
To use the toggle feature, you need to:
  1. 1.
    Click on the eye icon at the top-right-hand corner of the screen.
  2. 2.
    A pop-up box will open showing the performance metrics you can select
  3. 3.
    Click on the Toggle button. This will either select or unselect all performance metrics.
  4. 4.
    To close the pop-up box, click anywhere outside of the box.
Export as PDF
Copy link
Contents