说明：  利用笔记本摄像头输入人脸视频，进行自动心率估计。原理是人类血液对与各种频率的光照都有一定的吸收作用，而心跳会引起皮下的毛细血管血液流量变化，从而使皮肤的颜色在心跳的作用下进行周期性的变化。方法引用自论文Robust Pulse Rate From Chrominance-Based rPPG
(Remote photoplethysmography (rPPG) enables contactless monitoring of the blood volume pulse using a regular camera. We present an analysis of the motion problem, from which far superior chrominance-based methods emerge.)