Feature Set: FS-W-A-5
Overview
This feature set is targeted towards actigraphy style sleep detection using only IMU based sensor data available from wrist location. The feature set computes movement and z-angle features over temporal windows (e.g. 5 seconds) captured from IMU sensor.
Target Location/Sensors
The target location for this feature set is the wrist. From this location, the features are compute from the following raw sensors:
- IMU: Inertial measurement unit (IMU) data is used to compute movement and z-angle.
Dataset Support
- CMIDSS: This dataset provides pre-computed movement and z-angle data from the wrist location every 5 seconds.
Features
This feature set includes the following 5 features:
| Feature Name | Description | Sensor |
|---|---|---|
| tod | Time of day encoded using cosine | Time |
| mov_mu | Mean movement | IMU |
| mov_std | Standard deviation of movement | IMU |
| angle_mu | Mean z-angle | IMU |
| angle_std | Standard deviation of z-angle | IMU |
Output
The feature set is stored as HDF5 files (.h5) with one file per subject with path: {save_path}/{dataset}/{subject_id}.h5. Each HDF5 file includes the following entries:
/features: Time x Feature tensor (fp32). Features are computed over windows of sensor data./mask: Time x Mask tensor (bool). Mask indicates valid feature values./labels: Time x Label (int). Labels are sleep stages.