Rice University researchers are developing a highly accurate, touch-free system, Distance PPG, that can measure a patient’s pulse and breathing just by analyzing the changes in one’s skin color over time. Though the technique isn’t new, the researchers are making it work under conditions that have so far stumped earlier systems.
Where other camera-based systems have been challenged by low-light conditions, dark skin tones and movement, Distance PPG relies on algorithms that correct for those variables.
The team of Rice graduate student Mayank Kumar and professors Ashok Veera raghavan and Ashutosh Sabharwal created the system that will let doctors diagnose patients from a distance with special attention paid to those in low-resource settings.
Kumar, the project’s lead graduate researcher, said Distance PPG would be particularly helpful to monitor premature infants for whom blood pressure cuffs or wired probes could pose a threat.
He said that their key finding was that the strength of the skin-color change signal was different in different regions of the face, and so they developed a weighted-averaging algorithm, which improved the accuracy of derived vital signs, rapidly expanding the scope, viability, reach and utility of camera-based vital-sign monitoring.
By incorporating tracking to compensate for movement, even a smile, DistancePPG perceived a pulse rate to within one beat per minute, even for diverse skin tones under varied lighting conditions.
Kumar said he expects the software to find its way to mobile phones, tablets and computers so people can reliably measure their own vital signs whenever and wherever they choose.
The research appears in the Optical Society journal Biomedical Optics Express.