Blue as an Underrated Alternative to Green: Photoplethysmographic Heartbeat Intervals Estimation under Two Temperature Conditions.

Since photoplethysmography (PPG) sensors are usually placed on open skin areas, temperature interference can be an issue. Currently, green light is the most widely used in the reflectance PPG for its relatively low artifact susceptibility. However, it has been known that hemoglobin absorption peaks at the blue part of the spectrum.

An Exploration of Blue PPG Signal Using a Novel Color Sensorbased PPG System.

Reflectance photoplethysmography is a widely employed method in personal health assessment devices. We developed a remote PPG system for obtaining the signal from palm skin. For the handle-mounted design, it is crucial to ensure accurate measurements under a range of skin temperatures.