Remote Detection of Psychological Stress [JHAPL_FY05_090]

这项研究项目的目的是探索通过使用小型、隐蔽的、基于微波多普勒的传感器远程、非接触地测量心率、心率变异性和呼吸的变化来秘密检测受试者在提问过程中压力水平上升的可行性。使用对生理指标的隐蔽感知可以最大限度地减少甚至消除受试者使用对策的可能性，同时提供测量心率动态变化(“心率变异性”或HRV)的能力，反映自主神经系统(ANS)的活动，而自主神经系统(ANS)在精神刺激期间可测量地改变。基于微波的微型系统还具有潜在的医疗应用，例如对烧伤患者床边的生命体征进行非接触监测，以及用于研究，其中与心电(ECG)导联相关的不适可能会干扰研究，就像在睡眠呼吸暂停研究中，当受试者的不适改变正常睡眠习惯时可能发生的情况。之前的工作已经证明了微波-多普勒传感在测量呼吸、脉搏和眨眼方面的有效性。“不合作”主体的案例几乎没有受到关注。为了使基于微波的系统在现实环境中有用，必须解决与不合作的对象有关的几个问题，这些问题产生于：(1)突然的、不可预测的对象运动，(2)信号随胸部位置和入射角度的变化，以及(3)传感器与对象之间的距离随时间的波动。远程检测服务于许多医疗目的，包括在烧伤患者中，这些患者的心脏变异性标准传感器本身就有压力。

The aim of this research project is to investigate the feasibility of surreptitiously detecting elevated stress levels in a subject during questioning by remote, non-contact measurement of changes in heart rate, heart rate variability and respiration using small, concealable, microwave-Doppler-based sensors. The use of covert sensing of physiological indices could minimizeor even eliminate the use of countermeasures by the subject, while providing the ability to measure the dynamical changes of heart rate ("heart rate variability" or HRV) that reflect the activity of the autonomic nervous system (ANS), which is measurably altered during mental provocation. Miniaturized microwave-based systems also have potential medical applications, such as non-contact monitoring of vital signs at a bedside, for burn victims and for research, where the discomfort associated with electrocardiographic (ECG) leads may interfere with a study, as might occur in sleep apnea research when a subject's discomfort alters normal sleep habits. Previous work, has demonstrated the efficacy of microwave-Doppler sensing to measure respiration, pulse rate and eye blinks. The case of "uncooperative" subjects has received little attention. In order for a microwave-based system to be useful in realistic settings, several issues related to uncooperative subjects must be addressed concerning signal and noise variability arising from: (1) sudden, unpredictable subject movements, (2) variation of signal with location on the thorax and the angle of incidence, and (3) fluctuation of the distance between the sensor and the subject with time. Remote detection serves a number of medical purposes, including in burn patients which standard sensors of heart variability are in themselves stressful.