The application detects the heart-rate of an individual using the device webcam.
The algorithm uses a method called Photoplethysmography which is a novel video-based methodology for non-contact, automated cardiac pulse measurements. PPG was first described in the 1930s, as a simple low-cost optical technique to measure the blood volume changes. This method has the ability to sense the cardiovascular pulse wave i.e. blood volume pulse through variations in transmitted or reflected surrounding light. This webcam-based technique uses normal ambient light as a source of illumination for remote acquisition of PPG signals and a simple digital camera. This method takes into account the volumetric changes in the facial blood vessels during the cardiac cycle which modify the path length of the incident ambient light in a way that the subsequent changes in amount of reflected light indicate the timing of cardiovascular events i.e. the pulse.
The application needs to detect a human face. The current version only supports the front face camera. For a more accurate result, sit in a stable position with a moderate light in the surrounding area.
Once the user tabs the screen, part of the face is locked and the computation is started. During this process, the user must not move as this interferes with the computation result.
The algorithm provides an estimate of the pulse, and hence it is not aimed as a substitute of a medical device.