基于光体积描述记成像技术的非接触低成本生理信息的检测

在最近几十年,人们对低成本、非接触和普适方法测量生理信息(心率、心率变异性、血氧饱和度等)产生了浓厚的兴趣。传统的临床测量生理信息的方法包括Ag/AgCl电极测量心率和心率变异性,二氧化碳分析仪测量呼吸率状态,脉搏血氧饱和度仪测量血氧饱和度。这些方法虽然可以获得完美的信号,但是他们价格昂贵、使用麻烦、不方便。基于光体积描述记成像技术检测生理信息提供了一个人体生理健康检测的新方法。血流速度、血流量和血压可间接地评估血容量,反过来,血容量间接反映了这些生理参数的变换。光在人体组织的反射或透射可以得到血容量的变化。使用电脑摄像头或手机摄像头扑捉的人体皮肤表面成像,通过对成像光信号的处理和分析,获得一些生理信息,如心率、呼吸率、心率变异性和血氧饱和度等。在本文中,我们回顾使用光体积描述记成像技术在非接触健康检测领域里的最新发展,论述面临的挑战和将来的发展方向。

A Review of the Methods for Non-Contact, Low-cost Acquisition of Physiological Information based on Photoplethysmographic Imaging

In recent years, there has been increasing interest in low-cost, non-contact and pervasive methods for measuring physiological information, such as heart rate (HR), respiratory rate, heart rate variability (HRV) and oxyhemoglobin saturation. The conventional methods, such as wet adhesive Ag/AgCl electrodes for HR and HRV, the capnograph device for respiratory status, and pulse oximetry for oxyhemoglobin saturation could provide excellent signals but are expensive and inconvenient. A method to monitor physiological information based on photoplethysmographic imaging offers a new means for health monitoring. Blood volume can be indirectly assessed in terms of blood velocity, blood flow rate and blood pressure, which, in turn, can reflect changes in physiological parameters. Changes in blood volume can be determined from the spectra of light reflected from or transmitted through body tissues. Images of an area of the skin surface are consecutively captured with the color camera of a computer or smartphone and, by processing and analyzing the light signals, physiological information such as HR, respiratory rate, HRV and oxyhemoglobin saturation can be acquired. In this paper, we review the latest developments in using photoplethysmographic imaging for non-contact health monitoring and discuss the challenges and future directions for this field.