Best Practices - How to take a measurement

rPPG - Face scan

In order to get accurate vital-sign readings, follow the guidelines below:

Device

• Ensure battery level is above 20% and not in power-save mode.
• Ensure your camera lenses are clean and unscratched.
• Place device on a stand about 30 cm away from your face.
• Position the device with the selfie camera at eye level and parallel to
  the face.
• Use a stand to reduce shaking and movements of the device.

Subject

• Sit still during the measurement.
• Ensure your feet are placed flat on the floor and your legs are
  uncrossed.
• Make sure your face is fully exposed, ensuring it is not covered by hair or accessories (i.e., mask, sunglasses, hat).
• Avoid moving or talking throughout the measurement and remain focused on the screen until the measurement is complete.

Environmental Conditions

• Ensure your face is evenly illuminated
• Avoid measuring in locations with multiple light sources (preferably a
  single light source directed towards the face).
• Settle into a position where no light sources are directed toward the
  camera (e.g., by sitting against a wall).
• Ensure neither the camera nor the area in the frame is exposed to
  direct sunlight.
• Avoid movement of other persons behind or within your vicinity.
• Avoid highly reflective objects in the surrounding area, including
  mirrors, glass windows, tables, etc.
• Ensure the level of the light illuminating your face is a minimum
  of 400 lux.
• It is recommended that you use a cold light (>4500K) and not a
  monochromatic light source.

PPG - Finger scan

When using the By Finger (PPG) mode, following these best practice guidelines:

Device

• Ensure battery level is above 20% and not in power-save mode.
• Ensure your camera lenses are clean and unscratched.
• Keep your mobile device in a fixed position throughout the entire measurement.
• The device should be held by hand.

Subject

• Sit comfortably and use your free hand for support.
• Ensure your feet are placed flat on the floor and your legs
  are uncrossed.
• Hold your phone in a comfortable and stable position.
• Place the index finger on the appropriate rear camera and assure
  it fully covers the lens. Do not cover the flashlight. You will see
  your finger on the preview display when your finger is placed on
  the appropriate camera.
• Apply moderate and constant pressure when placing your finger
  on the camera.
• Avoid moving or talking throughout the measurement and remain
  at rest throughout the measurement.
• Avoid moving your finger during the measurement.
• iPhone users: cover both the rear flashlight and camera with your index finger.
• Android users: cover the rear camera with your index finger without covering the rear flashlight.

Environmental Conditions

• Measurements should not be taken in complete darkness.