Photonic Radar Monitors Breathing From A Distance

Engineers at the University of Sydney have developed a photonic radar that allows them to monitor breathing rates without the need to attach equipment to a patient’s skin. Wired or more invasive systems may not be suitable for everyone – for instance, burn patients with damaged skin or infants with a tiny body surface area may not be able to avail of such systems. This latest technology can monitor breathing remotely and may enable multiple patients to be monitored from one base station. The technology relies on a light-based system to generate and collect radar signals, which results in very precise measurements.

Keeping track of vital signs, such as breathing, in crucially ill patients is important, but current technologies to achieve this may not be suitable for everyone. For instance, a burn patient may not appreciate sensors that require skin contact, and a new-born baby may not have enough skin surface area to accommodate large sensors or bulky equipment. Other issues include the risk of cross-contamination between patients caused by the installation of such sensors or even discomfort because of the sensors.

A non-invasive way to monitor breathing would be beneficial for such patients. Non-invasive systems involving infrared or optical wavelength cameras have been trialed before, but they come with some issues. “Camera-based systems have two problems,” said Ben Eggleton, a researcher involved in the study. “One is high sensitivity to variations in lighting conditions and skin colour. The other is with patient privacy, with high-resolution images of patients being recorded and stored in cloud computing infrastructure.”

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These researchers turned to photonic radar as a way to measure and track the subtle movements of our bodies when we breathe. So far, they have tested the technology with cane toads and have been able to track their breathing successfully.

“Photonic radar uses a light-based, photonics system – rather than traditional electronics – to generate, collect and process the radar signals,” said Ziqian Zhang, another researcher involved in the study. “This approach allows for very wideband generation of radio frequency (RF) signals, offering highly precise and simultaneous, multiple tracking of subjects. Our system combined this approach with LiDAR – light detection and ranging. This hybrid approach delivered a vital sign detection system with a resolution down to six millimetres with micrometre-level accuracy. This is suitable for clinical environments.”

See a video demonstrating the technology below (toad included).

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