Mazdeyasna Siavash, Ghassemi Pejman, Wang Quanzeng
Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA.
Sensors (Basel). 2023 Sep 21;23(18):8011. doi: 10.3390/s23188011.
Infrared thermographs (IRTs) are commonly used during disease pandemics to screen individuals with elevated body temperature (EBT). To address the limited research on external factors affecting IRT accuracy, we conducted benchtop measurements and computer simulations with two IRTs, with or without an external temperature reference source (ETRS) for temperature compensation. The combination of an IRT and an ETRS forms a screening thermograph (ST). We investigated the effects of viewing angle (, 0-75°), ETRS set temperature (TETRS, 30-40 °C), ambient temperature (Tatm, 18-32 °C), relative humidity (RH, 15-80%), and working distance (, 0.4-2.8 m). We discovered that STs exhibited higher accuracy compared to IRTs alone. Across the tested ranges of Tatm and RH, both IRTs exhibited absolute measurement errors of less than 0.97 °C, while both STs maintained absolute measurement errors of less than 0.12 °C. The optimal TETRS for EBT detection was 36-37 °C. When was below 30°, the two STs underestimated calibration source (CS) temperature (TCS) of less than 0.05 °C. The computer simulations showed absolute temperature differences of up to 0.28 °C and 0.04 °C between estimated and theoretical temperatures for IRTs and STs, respectively, considering of 0.2-3.0 m, Tatm of 15-35 °C, and RH of 5-95%. The results highlight the importance of precise calibration and environmental control for reliable temperature readings and suggest proper ranges for these factors, aiming to enhance current standard documents and best practice guidelines. These insights enhance our understanding of IRT performance and their sensitivity to various factors, thereby facilitating the development of best practices for accurate EBT measurement.
在疾病大流行期间，红外热成像仪（IRT）通常用于筛查体温升高（EBT）的个体。为了解决关于影响IRT准确性的外部因素的研究有限的问题，我们使用两台IRT进行了台式测量和计算机模拟，有无外部温度参考源（ETRS）进行温度补偿。IRT和ETRS的组合形成了筛查热成像仪（ST）。我们研究了视角（，0-75°）、ETRS设定温度（TETRS，30-40°C）、环境温度（Tatm，18-32°C）、相对湿度（RH，15-80%）和工作距离（，0.4-2.8 m）的影响。我们发现，与单独的IRT相比，ST表现出更高的准确性。在测试的Tatm和RH范围内，两台IRT的绝对测量误差均小于0.97°C，而两台ST的绝对测量误差均保持在小于0.12°C。用于EBT检测的最佳TETRS为36-37°C。当低于30°时，两台ST低估校准源（CS）温度（TCS）小于0.05°C。计算机模拟显示，考虑到0.2-3.0 m的、15-35°C的Tatm和5-95%的RH，IRT和ST的估计温度与理论温度之间的绝对温度差分别高达0.28°C和0.04°C。结果强调了精确校准和环境控制对于可靠温度读数的重要性，并提出了这些因素的适当范围，旨在加强当前的标准文件和最佳实践指南。这些见解增强了我们对IRT性能及其对各种因素敏感性的理解，从而有助于制定准确EBT测量的最佳实践。
