Turning a pyroelectric infrared motion sensor into a high-accuracy presence detector by using a narrow semi-transparent chopper
Turning a pyroelectric infrared motion sensor into a high-accuracy presence detector by using a narrow semi-transparent chopper
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DOI：
10.1063/1.4998430
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发表时间：
2017-12-11
影响因子：
4
通讯作者：
Lin, Hanbing
中科院分区：
文献类型：
--
作者：
Liu, Haili;Wang, Ya;Lin, Hanbing
热释电红外（PIR）传感器是最流行的存在探测器。然而，它们的应用仅限于运动检测，因为热释电传感元件只对辐射热功率波动敏感。这封信报告了一个切碎PIR （C-PIR）存在传感器，能够通过引入一个狭窄的半透明光学切碎器来周期性地关闭入射辐射，以高精度地检测静止和移动的居住者。更重要的是，尽管窄斩波器可以有效地屏蔽固定人员辐射的单向红外（IR）功率，但它对周围环境辐射的全向功率的影响几乎为零。因此，C-PIR传感器在有人居住和无人居住场景之间产生的电压差可以直接用于高精度识别静止居住者的存在。对于移动乘员检测，光学斩波器几乎不受辐射功率变化的影响，因此可以实现与车载PIR相同的高精度检测。建立了一个近似的理论模型来说明被光学斩波器阻挡的红外辐射的物理和动力学。通过参数研究、实验表征和经验分析，获得斩波器厚度和斩波频率的最佳设置。实验结果表明，C-PIR传感器可以检测4.0米内的静止人员和8.0米内的移动人员，同时保持100%的精度。发现C-PIR的视场为水平110度和垂直90度，与机载PIR传感器的视场一致。AIP出版社出版。
Pyroelectric infrared (PIR) sensors are the most popular presence detectors. However, their applications arc limited to motion detection only, as the pyroelectric sensing clement is only sensitive to radiated heat power fluctuation. This letter reports a chopped PIR (C-PIR) presence sensor, capable of detecting both the stationary and the moving occupants at high accuracy by introducing a narrow semi-transparent optical chopper to shutter the incident radiation periodically. More importantly, even though the narrow chopper can efficiently shutter the unidirectional infrared (IR) power radiated by stationary occupants, it has near-zero influence on the omnidirectional power radiated from the ambient environment. Therefore, the voltage difference generated by the C-PIR sensor between occupied and unoccupied scenarios can be directly used for identifying the presence of stationary occupants with high-accuracy. For moving occupant detection, the optical chopper can barely affect the variation of the radiated power and thus lead to the same high-accuracy detection as the on-board PIR. An approximate theoretical model is created to illustrate the physics and dynamics of IR radiation shuttered by the optical chopper. Parametric studies, experimental characterization, and empirical analysis were performed to obtain the optimal setting of the chopper in terms of its thickness and chopping frequency. Experimental results reveal that the C-PIR sensor can detect stationary occupants for up to 4.0 m and moving occupants for up to 8.0 m, while maintaining an accuracy of 100%. The field of view of the C-PIR was found at 110 degrees horizontally and 90 degrees vertically, consistent with that of the on-board PIR sensor. Published by AIP Publishing.