Abstract：
Respiration is an invaluable signal that facilitates the real-time observation of physiological dynamics. In recent years, the advancement of noncontact measurement technology has gained momentum in capturing physiological activities in natural settings. This technology is anticipated to be found not only in humans but also in nonhuman primates. Currently, the predominant noncontact approach for nonhuman animals involves measuring vital signs through subtle variations in skin color. However, this approach is limited when addressing areas of the body covered with hair or when working in outdoor settings under fluctuating sunlight. To overcome this issue, we focused on noncontact respiratory measurements using millimeter-wave radar. Millimeter-wave radar systems, which employ millimeter waves that can penetrate animal fur and estimate respiration-derived periodic body motion, exhibit minimal susceptibility to sunlight interference. Thus, this method shows potential for conducting noncontact vital measurements in natural and outdoor settings. In this study, we validated a millimeter-wave radar methodology for capturing respiration in outdoor-housed rhesus macaques (Macaca mulatta). The radar was positioned beyond the captive enclosure and maintained at a distance >5 m from the target. Millimeter waves were transmitted to the target, and the reflected waves were used to estimate skin surface displacement associated with respiration. The results revealed periodic skin surface displacement, and the estimated respiratory rates weres within the reported range of respiratory rates for rhesus macaques. These results suggest the potential applicability of millimeter-wave radar for noncontact respiration monitoring in outdoor-living macaques without anesthesia or immobilization. The continued advancement of noncontact vital measurement technology will contribute to understanding primate mental and physical dynamics during their daily life.
摘要：
呼吸是促进生理动态的实时观察的宝贵信号。近年来,非接触测量技术的进步在捕捉自然环境中的生理活动方面获得了动力。预计该技术不仅在人类中而且在非人类灵长类动物中发现。目前,非人类动物的主要非接触方法包括通过皮肤颜色的细微变化来测量生命体征。然而,这种方法是有限的，当处理覆盖有头发的身体区域或在户外环境下工作时，阳光波动。为了克服这个问题，我们专注于使用毫米波雷达进行非接触式呼吸测量。毫米波雷达系统,使用毫米波可以穿透动物皮毛并估计呼吸衍生的周期性身体运动，表现出最小的敏感性阳光干扰。因此，这种方法显示了在自然和户外环境中进行非接触生命测量的潜力。在这项研究中,我们验证了毫米波雷达方法用于捕获室外恒河猴（Macacamulatta）的呼吸。雷达位于捕获外壳之外，并与目标保持>5m的距离。毫米波被传送到目标,反射波用于估计与呼吸相关的皮肤表面位移。结果显示皮肤表面周期性位移，估计的呼吸频率在恒河猴呼吸频率的报告范围内。这些结果表明，毫米波雷达在没有麻醉或固定的情况下对户外生活猕猴进行非接触式呼吸监测的潜在适用性。非接触式生命测量技术的不断进步将有助于理解灵长类动物在日常生活中的心理和身体动态。
