The same technology that scans you at the airport could soon help monitor your health without waiting for you to put on your wristbands or electrodes. Using millimeter-wave spread-spectrum radar technology, researchers from Kyoto University and Panasonic Corp say they can measure heartbeats remotely and in real time, with accuracy matching electrocardiograms.
This proof of principle reveals the next leap in medical technology — one that makes health metrics more automatic. The researchers say the development enables casual sensing, that is taking measurements as people go about their daily activities, such as when they are going to bed or getting ready to start the day. What is intriguing about the technology is that it offers an ability to take these measurements without requiring a wearable device.
“Taking measurements with sensors on the body can be stressful and troublesome, because you have to stop what you’re doing,” said Hiroyuki Sakai, a researcher at Panasonic. “What we tried to make was something that would offer people a way to monitor their body in a casual and relaxed environment.”
The researcher says users don’t need to place sensors on the body, but that under controlled conditions, the accuracy is comparable to electrocardiographs. “We compared inter-beat intervals measured by our system with that of ECG, and found that they are almost equivalent,” says Toru Sato professor of communications and computer engineering at Kyoto University. The test system was able to detect vital signals within a range of about 1m. Sato says the team plans to extend the maximum range to about 5m by improving the signal processing hardware in the next system within a year or so.
The incentive for users is clear. The design does not interfere with a patient’s daily routine, but provides automatic monitoring of their health status. Sato says the inspiration for the device came from search and rescue technology. “Detection of very small Doppler shift in radar echoes due to motions of human body has long been studied for finding people buried under snow or debris for rescue purposes,” he explains. “Recent advances in UWB (ultra wideband) radars have opened new possibilities of detecting vital signals during our daily activities.”
And the team sees opportunity beyond heartbeats. “Heartbeats aren’t the only signals the radar catches. The body sends out all sorts of signals at once, including breathing and body movement,” says Sato. He explains that the radar system it the same principle used in anti-collision radars for cars, but far more sensitive. “The major difference is that we need to detect motions of less than a millimeter while vehicle radars deal with motions of meters.”
The remote sensing system combines millimeter-wave spread-spectrum radar technology and a unique signal analysis algorithm that identify signals from the body. “It’s a chaotic soup of information,” said Sato. “Our algorithm differentiates all of that. It extracts waves characteristic of heart beats from the radar signal and calculates their intervals.”
More experimentation is needed to ensure accuracy across various age ranges and environments, says Sato. Panasonic Co., is making decisions about the marketing of the final product. Sato says the company plans to develop an extensive healthcare service “including the vital signal sensing as a sensor element, although the details are to be fixed in a near future.”
