Webcams May Now Record Vital Signs

Vital signs—which typically include heart rate, respiratory rate, body temperature, and blood pressure—may now be able to be monitored using a webcam, according to a study published by researchers at the Harvard-MIT Division of Health Sciences and Technology and the MIT Media Lab.

In this study, the researchers focused on measuring heart rate using low-resolution webcams. The cameras, which can accurately detect health indicators in household or work settings, enable one to record vital sign readings, like a patient’s heart rate, just by sitting in front of a computer or a webcam-affixed mirror.

“One of the biggest advantages is that it is inexpensive and easy to use; you need a simple digital camera or a webcam,” said lead author Ming-Zher Poh, a graduate student in the HST program.

Real time monitoring of vital signs might also help with preventative screening, which the researchers believe will be a useful diagnostic tool.

“By integrating [a webcam] to your computer or mirror, it becomes a daily routine to get a [vital sign] reading, [allowing one to] collect long term data for days or months,” Poh adds. “The computer or mirror can also act as a portal for telemedicine with a physician,” an intervention that Poh explained could reduce hospital visits while facilitating early disease detection.

The technology uses webcams to record cardiac pulse waves detected from a human face. The researchers explained that heart rate modifies volumetric changes in facial blood vessels, which alters the path of ambient light. Scientists can then use mathematical algorithms to calculate the amount of light reflected from a face to determine heart rate.

Reducing unwanted reflective light sources was one of the most difficult challenges, according to Poh. Factors such as small bodily movements or minor environmental light changes cause fluctuations in the light source and can significantly alter reading accuracy.

The researchers’ ability to overcome this challenge—a key finding in the work—was accomplished by using processing methods that extract signals from the heart while reducing unwanted noise.

The technology has begun to attract investors, and Poh said that they are continuing to work on further improvements.

“This was a proof of concept,” Poh said. “We want to push it further to more physiological signals such as respiration rate, oxygen saturation, and blood pressure.”

The study was published in a recent issue of the journal Optics Express.