Head Angle
This app is used to measure the head angles: obliquity, rotation, and tilt. This app is intended to be used as a quick diagnostic tool for torticollis and generates a report with the max angle achieved for each angle.
Nodes Required: 2
Sensing (2):
forehead (switch pointing superiorly)
thorax (switch pointing superiorly)
Feedback (0)
Algorithm & Calibration
Algorithm Information
The raw quaternions from the IMU are converted to Euler angles, and the roll angle is extracted using well established mathematical principles. If you'd like to learn more about quaternion to Euler angles calculations, we suggest starting with this Wikipedia page: Conversion between quaternions and Euler angles
Calibration Process:
The participant's torso should be either vertical (standing or sitting with their back next to a wall) or horizontal (laying flat on their back). The app takes the initial position when the app starts as in alignment.
Description of Data in Downloaded File
Calculated Fields
time (sec): time since trial start
body_orientation: 1 indicates vertical orientation (standing or sitting with their back next to a wall), 0 indicates horizontal orientation (laying flat on their back).
head_tilt (deg): the angle of the head tilt. Positive values are upward tilt, negative values are downward tilt.
head_obliquity (deg): the angle of the head obliquity. Positive values are to the left, negative values are to the right.
head_rotation (deg): the angle of the head rotation. Positive values are to the left, negative values are to the right.
max_head_rotation (deg): the max angle of head rotation to the left achieved so far.
min_head_rotation (deg): the max angle of head rotation to the right achieved so far.
max_head_tilt (deg): the max angle of head tilt upward achieved so far.
min_head_tilt (deg): the max angle of head tilt downward achieved so far.
max_head_obliquity (deg): the max angle of head obliquity to the left achieved so far.
min_head_obliquity (deg): the max angle of head obliquity to the right achieved so far.
annotations: if any annotations are sent to the dashboard chart, they will also be listed here.
audio_feedback: if any audio feedback is sent to the dashboard, it will also be listed here.
user_defined_status: the prompts displayed to the user on the dashboard, will also be listed here.
Sensor Raw Data Values
Please Note: Each of the columns listed below will be repeated for each sensor
SensorIndex: index of raw sensor data
AccelX/Y/Z (m/s^2): raw acceleration data
GyroX/Y/Z (deg/s): raw gyroscope data
MagX/Y/Z (μT): raw magnetometer data
Quat1/2/3/4: quaternion data (Scaler first order)
Sampletime: timestamp of the sensor value
Package: package number of the sensor value