School of Basic Science, Hanbat National University, Daejeon 34158, Korea.
Department of Environmental Engineering, Pukyong National University, Busan 48613, Korea.
Sensors (Basel). 2021 Nov 1;21(21):7282. doi: 10.3390/s21217282.
Images based on RGB pixel values were used to measure the extinction coefficient of aerosols suspended in an atmospheric state. The pixel values of the object-image depend on the target-object reflection ratio, reflection direction, object type, distances, illumination intensity, atmospheric particle extinction coefficient, and scattering angle between the sun and the optical axes of the camera, among others. Therefore, the imaged intensity cannot directly provide information on the aerosol concentration or aerosol extinction coefficient. This study proposes simple methods to solve this problem, which yield reasonable extinction coefficients at the three effective RGB wavelengths. Aerosol size information was analogized using the RGB Ångström exponent measured at the three wavelengths for clean, dusty, rainy, Asian dust storm, and foggy days. Additionally, long-term measurements over four months showed reasonable values compared with existing PM measurements and the proposed method yields useful results.
基于 RGB 像素值的图像被用于测量悬浮在大气状态下的气溶胶的消光系数。目标图像的像素值取决于目标物体的反射率、反射方向、物体类型、距离、光照强度、大气粒子消光系数以及太阳和相机光轴之间的散射角等因素。因此，成像强度不能直接提供气溶胶浓度或气溶胶消光系数的信息。本研究提出了简单的方法来解决这个问题，这些方法在三个有效 RGB 波长下产生了合理的消光系数。使用在三个波长下测量的 RGB Ångström 指数模拟了气溶胶大小信息，用于清洁、尘土飞扬、雨天、亚洲沙尘暴和有雾的天气。此外，四个月的长期测量结果与现有的 PM 测量值相比显示出合理的值，并且该方法得出了有用的结果。
