Tech Briefs

Software for Non-Contact Measurement of an Individual’s Heart Rate Using a Common Camera

A software application detects the heart rate of an individual by using a real-time video stream from a common camera connected to their computer. This involves no contact between the user and the camera, or calibration between individual users. NASA’s OpenMDAO framework was used to implement and coordinate the necessary data acquisition and signal processing functions.

The software finds the location of the user’s face within an incoming stream of images from a connected camera, and then isolates the forehead region. Data is collected from this location for a segment of time to estimate the user’s heart rate by measuring average optical intensity in the forehead location, in the subimage’s green channel alone. A bandpass filter designed to isolate and magnify spectral components between 0.8 Hz and 3 Hz is computed on the gathered optical intensity data. With good lighting and minimal noise due to motion, a stable heartbeat is isolated in about 15 seconds. Accuracy has been tested against commercial heart rate monitors used for sports medicine.

Once the user’s heart rate has been estimated, real-time phase variation associated with this frequency is also computed. This allows for the heartbeat to be exaggerated in the post-process frame rendering, causing the highlighted forehead location to pulse in sync with the user’s own heartbeat.

This work was done by Tristan Hearn of Glenn Research Center. The application was developed at NASA Glenn Research Center in support of OpenMDAO, under the Aeronautical Sciences Project in NASA’s Fundamental Aeronautics Program, as well as the Crew State Monitoring Element of the Vehicle Systems Safety Technologies Project, in NASA’s Aviation Safety Program.

Inquiries concerning rights for the commercial use of this invention should be addressed to NASA Glenn Research Center, Innovative Partnerships Office, Attn: Steven Fedor, Mail Stop 4–8, 21000 Brookpark Road, Cleveland, Ohio 44135. LEW-19090-1