Vision-based thermal comfort quantification for HVAC control
Vision-based thermal comfort quantification for HVAC control
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DOI：
10.1016/j.buildenv.2018.05.018
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发表时间：
2018-09
影响因子：
7.4
通讯作者：
Wooyoung Jung;F. Jazizadeh
中科院分区：
文献类型：
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作者：
Wooyoung Jung;F. Jazizadeh
这项研究提出了一种基于视觉的方法，使用RGB视频图像作为唯一来源来推断人体的体温调节状态，以响应室内环境中的热条件变化。主要目标是为我们设想的基于温度调节的暖通空调控制做出贡献，该控制利用最终用户的温度调节状态的实际热需求来提高能源效率。鉴于设想的控制系统需要在非侵入性、适用性、敏感性和普适性(即可行性和可扩展性)四个约束下的测量技术，本研究调查了无处不在的RGB视频图像(通过网络摄像头或智能手机)的潜力。使用光体积描记术(PPG)，这是一种著名的光学技术，用于测量皮肤微血管床中的血液体积变化，我们利用皮肤表面(血管的扩张和收缩)的血流控制机制来调节散热，反映在PPG信号的幅度上。考虑到PPG信号的细微变化和对噪声的敏感性，我们提出了一种结合独立分量分析和自适应滤波的框架，在保留PPG信号反映热生理状态的幅度信息的同时，减少不需要的和带内伪影。使用瞬时热条件对该框架进行了实验评估，以考虑适用性和敏感性属性。因此，在没有考虑稳定体温调节状态的适应时间的情况下，受试者被暴露在不同的温度(∼20-30 °C)中，同时报告他们的热感觉。总体而言，对于15名受试者中的10名，基于视觉的指标、皮肤温度和热感之间的正相关被观察到，这表明在以足够的敏感度推断乘员的热感方面具有很好的潜力。
This study presents a vision-based approach that employs RGB video images as the sole source for inferring thermoregulation states in the human body in response to thermal condition variations in indoor environments. The primary objective is to contribute to our envisioned thermoregulation-based HVAC control that leverages actual thermal demands from end-users’ thermoregulation states for increased energy efficiency. Given that the envisioned control system calls for measurement techniques under four constraints of non-intrusiveness, applicability, sensitivity, and ubiquity (i.e., feasibility and scalability), this study investigated the potentials of ubiquitously obtainable RGB video images (through webcams or smartphones). Using photoplethysmography (PPG), a well-known optical technique for measuring blood volume changes in the microvascular bed of skin, we have leveraged the mechanism of blood flow control to the skin surface (blood vessels' dilation and constriction) for heat dissipation regulations, reflected in PPG signal's amplitude. Given the subtle variations of PPG signals and their susceptibility to noise, we proposed a framework that uses a combination of independent component analysis and adaptive filtering to reduce unwanted and in-band artifacts while preserving the amplitude information of PPG signals that indicates thermophysiological states. The framework was experimentally evaluated using transient thermal conditions to account for applicability and sensitivity attributes. Therefore, without considering an acclimation time for stabilized thermoregulation states, human subjects were exposed to varying temperatures (∼20–30 °C) while reporting their thermal sensations. In total, for 10 human subjects out of 15, a positive correlation between vision-based indicators, skin temperature, and thermal sensations were observed demonstrating promising potential in inferring thermal sensations of occupants with sufficient sensitivity.