Real-time Heart Activity Monitoring with Optical Illusion using a Smartphone- Raw data

In this study, we obtained a
pulsatile photoplethysmogram signal from a fingertip using the built-in camera
of an iPhone 6s and displayed a real-time heart activity images with
holographic projection on a smartphone screen. Our proposed heart activity hologram
is simple and can be easily realized with only a smartphone and overhead
projector (OHP) film. A square pyramid-shaped OHP film was positioned on a
smartphone screen. The actual cardiac cycle on the smartphone screen was
projected onto the film while measuring the pulsatile signal from a fingertip
placed on the smartphone’s
camera. The heart’s beat-to-beat time interval
was then recorded. This approach enables observation of one’s
own virtual heart activity in real time, rather than seeing a pulsatile signal
graphically on a smartphone. To investigate the feasibility of this heart
activity monitoring based on holographic projection, we tested it under
different conditions in terms of environmental light, smartphone screen light
intensity, and film color, and quantified the contrast-to-noise ratio for
comparison