New Sensor Could Bring Contactless Vital Sign Monitoring to Hospital Bedsides

However, camera-based systems often struggle to detect weak physiological signals when patients move or lighting is poor. To make monitoring more reliable under these conditions, researchers have developed a compact optical sensor designed to measure core vital signs without skin contact.

The goVISCAN vital sign sensor was created by the Fraunhofer Institute for Applied Optics and Precision Engineering (Fraunhofer IOF; Jena, Germany) in collaboration with partners in the Advanced Multimodal Imaging consortium. Measuring 10 × 7.5 × 2.5 centimeters, the compact device is designed to operate reliably despite changes in ambient lighting and patient movement. It currently offers a 40-degree field of view and works at distances ranging from 70 centimeters to 1.3 meters, allowing discreet placement near hospital beds or clinical workstations.

The system captures physiological information using a snapshot multispectral camera that records several wavelengths of light at once. A 3 × 3 micro-lens array divides incoming light into nine spectral channels spanning blue, green, red, and near-infrared wavelengths, with each lens projecting its own image onto a shared 1.25-megapixel sensor. Built-in light-emitting diodes help maintain consistent illumination. 

By combining data from the nine channels, goVISCAN detects subtle changes in skin brightness caused by pulsating blood flow and uses these signals to determine heart rate, respiratory rate, and oxygen saturation.

In an initial pilot study under controlled laboratory conditions, researchers evaluated goVISCAN in 12 participants against a finger pulse oximeter reference. Mean error was 1.3 breaths per minute for respiratory rate, 2.8 beats per minute for heart rate, and 3.8 percentage points for oxygen saturation. 

Study findings were published in Optical Instrument Science, Technology, and Applications IV. The next step is testing in clinical settings. Potential health care applications include inpatient bed monitoring and telemedicine encounters, with additional relevance to driver vigilance monitoring and control‑room safety.

“Many existing camera-based methods work only under ideal conditions. As soon as the measurement scene is not optimally illuminated or the person being measured moves, the weak physiological signals are quickly overlaid by perturbations,” said Martin Hubold, a researcher at Fraunhofer IOF.

“Our goal was to create a sensor that measures reliably even under realistic conditions—and is compact enough to be discreetly integrated into everyday environments,” said Hubold.

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