Hybrid optical imaging technology for long-term remote monitoring of skin perfusion and temperature behavior.

Photoplethysmography imaging (PPGI) and infrared thermography imaging (IRTI) are contactless camera-based measurement methods for monitoring a wide range of basic vital parameters. In particular, PPGI enhances the classical contact-based photoplethysmography. Approved evaluation algorithms of the well-established PPG method can easily be adapted for detection of heart rate, heart rate variability, respiration rate (RR), respiratory variability (RV), and vasomotional activity with PPGI. The IRTI method primarily records temperature distribution of the observed object, but information on RR and RV can also be derived from IRTI by analyzing the development of temperature distribution in the nasal region. The main advantages of both monitoring methods are unobtrusive data acquisition and the possibility of assessing spatial assignment between vital parameters and body region. Hence, these methods enable long-term monitoring or the monitoring of effects with special local characteristics. Because the two systems supplement each, a combined hybrid application is proposed and its feasibility discussed.