Photoplethysmography Imaging – Future Prospects and Challenges

Photoplethysmography Imaging (PPGI) is a rather novel technique to unobtrusively acquire vital information with a camera.PPGI allows contactless and spatial assessment of peripheral perfusion.Due to its unobtrusive spatiotemporal characteristics, PPGI offers great potential and new possibilities for diagnostics and monitoring.Measurement of heart rate, breathing rate, heart rate variability, oxygen saturation, perfusion strength, and blood pressure correlates, among others, have been reported.Recent works have demonstrated novel clinical applications.In contrast to contact-based photoplethysmography, the spatiotemporal resolution of PPGI provides access to additional information.However, despite a wide range of possibilities, PPGI has barely realized its potential in practical use to date.The technology holds many pitfalls as it relies on complex processing pipelines including not only signal processing but also image and video processing.At the same time, algorithms and datasets are rarely made public.While the design principles of PPGI measurements are complex, the application of PPGI is as simple as recording a video.This renders PPGI ideal for multi-parameter monitoring in telemedicine, for scenarios that require spatial resolution, and for vulnerable patients in which contact-based measurements are unsuitable.