New device works contact-free with photonic radar and LiDAR
A photonic radar can be used to monitor the breathing of multiple patients simultaneously without contact. The device was developed by researchers at the University of Sydney (https://www.sydney.edu.au/). Until now, patients have to be connected to devices by cable to monitor their vital signs. However, this disturbs their sleep and in many cases, such as severe burns, is not even possible. The device will be used in hospitals, elderly care facilities and at home to monitor people with respiratory problems without contact. The study (https://www.nature.com/articles/s41566-023-01245-6) appeared in Nature Photonics.
Camera monitoring brings privacy issues
So far, non-contact monitoring has been possible with cameras, but there are privacy issues with that, because “high-resolution images of patients would have to be recorded and stored in cloud computing infrastructure,” says Ben Eggleton, who helped develop the device. In addition, he says, they are unreliable when lighting conditions change and can’t cope with different skin tones.
“Photonic Radar uses a light-based photonic system instead of conventional electronics to generate, collect and process radar signals,” explains co-developer Ziqian Zhang. “This approach allows for very broadband generation of high-frequency signals, enabling highly accurate and simultaneous multiple tracking of subjects.”
Perfect tandem with LiDAR
The researchers added Light Detection and Ranging (LiDAR), which uses pulsed light waves to measure distance, to their photonic system. While LiDAR alone provides good range and resolution, its ability to penetrate objects is limited. The combination of radar and LiDAR provides the highest level of surveillance reliability.
In tests, scientists determined that the radar accurately detected the breathing rate of two targets about 25 centimeters apart in real time. It detected irregular breathing patterns in the range of seconds, including unusually long inhalations and exhalations, as well as pauses in breathing. The device even worked on a toad, where the area that moves during breathing is very small.