0LAUK0 2018Q1 Group 2 - Programming overview

Processing code layout

User object has

• Average location (x,y,z detected by OpenCV and IR)
• Ideal location (x,y,z of center of screen)
• Max RSI preventive compliant posture (how extreme can the user posture be without breaking the RSI prevention rules)
• Time spent in current posture
• Pixel map of face at startup
• Precision measure of repeated observations of face pixel map.

Cameras have

• Conversion metrics to transform pixels into angles into meters

Arduino IR has

• Conversion metric to transform voltage into meters

At startup

• User's face will be around their ideal location, capture the pixel map of the face detected around this location
• Load equipment and user attributes mentioned above.

At a predefined interval - call openCV to detect faces

• If no face is detected, maintain the average face location calculated from previous face detections
• If one face is detected, compare to face pixel map
  • If similarity is too low, maintain the average face location calculated from previous face detections
  • If similarity is high, update the average face location
• If multiple faces are detected, compare detected faces to face pixel map
  • If there is no match, maintain the average face location calculated from previous face detections.
  • If there is one match, update average face location using this face.
  • If there are multiple matches, choose faces closest to average face location and update average face location using this face.
• If the current location of the face is significantly different from the average face location:
  • Start counting time that this new posture is held:
    • If time is very low: it was a split movement, no long term change in posture -> ignore
    • If time is long: it is a long term change in posture -> move monitor
  • If detected as posture change:
    • Face has moved up or down:
      • Calculate delta_x, delta_y. give command to move monitor, when the monitor is in front of the user, calculate delta_z using the arduino IR. Give command to move monitor in z direction if delta_z > threshold
    • Detected face width has changed: (user moved forward or backward)
      • Calculate delta_z using the arduino IR. Give command to move monitor in z direction if delta_z > threshold
    • Determine if new posture is RSI preventive compliant

Keep track of how long a posture is held

• If posture is RSI prevention compliant: held for too long, notify user to move
• If posture is not RSI prevention compliant: use a much shorter time threshold, notify user sooner