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Since the majority of people have smartphones, the Hb level can be determined using the smartphone's video through PPG signal as opposed to the traditional approaches, which still require the use of a needle to puncture a vein. This study enrolled 108 subjects who underwent a clinical test, with their hemoglobin (Hb) level within the range of 6.6 to 16.5 g/dL. To mitigate potential variability in Hb levels during a brief period, 15-second recordings of the pointer finger were captured by utilizing a smartphone prior to the clinical test.  When the user places their finger on the phone's camera to record data, the camera flashlight briefly illuminates the area. The captured video is transformed to 60 fps as capturing a PPG signal at 60 fps provides a more detailed and accurate representation of changes in blood volume and heart rate compared to a lower frame rate

由于大多数人都拥有智能手机，血红蛋白（Hb）水平可通过智能手机视频提取光电容积脉搏波（PPG）信号来测定，而传统方法仍需使用针头穿刺静脉。本研究招募了108名受试者进行临床试验，其血红蛋白水平介于6.6至16.5克/分升之间。为减少短时间内血红蛋白水平可能出现的波动，在临床试验前使用智能手机对受试者的食指进行了15秒的记录。当用户将手指放在手机摄像头上来记录数据时，摄像头闪光灯会短暂照亮该区域。捕获的视频被转换为60帧/秒（fps），因为与较低帧率相比，以60帧/秒捕获PPG信号能更详细、准确地反映血容量和心率的变化。