Hologram_DataAnalysis.xlsx

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

本研究借助iPhone 6s的内置摄像头从指尖采集搏动式光电容积描记（photoplethysmogram）信号，并通过全息投影技术在智能手机屏幕上呈现实时心脏活动影像。我们提出的心脏活动全息投影方案结构简易，仅需智能手机与投影胶片（overhead projector, OHP）即可轻松实现。将方形金字塔造型的OHP胶片放置于智能手机屏幕上方，当将指尖置于手机摄像头处以采集搏动信号时，手机屏幕上的实际心动周期影像会投射至该胶片上，随后记录心脏的逐搏间期。该方案可使用户实时观测自身的虚拟心脏活动，而非仅在智能手机上以图形化方式查看搏动信号。为验证基于全息投影的心脏活动监测方案的可行性，我们在环境光照、智能手机屏幕亮度及胶片颜色等不同条件下开展了测试，并量化了对比度噪声比（contrast-to-noise ratio, CNR）以进行对比分析。