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Aerosol-extinction Retrieval Method at Three Effective RGB Wavelengths Using a Commercial Digital Camera

상용 디지털 카메라를 이용한 3가지 유효 RGB 파장에서의 미세먼지 소산계수 산출법

  • Park, Sunho (Department of Physics, Kongju National University) ;
  • Kim, Dukhyeon (School of Basic Science, Hanbat National University)
  • 박선호 (국립공주대학교 물리학과) ;
  • 김덕현 (국립한밭대학교 기초과학부)
  • Received : 2020.01.23
  • Accepted : 2020.03.05
  • Published : 2020.04.25

Abstract

In this article, we suggest a new method for measuring an aerosol's extinction coefficient using a commercial camera. For a given image, we choose three pixel-points that are imaged for the same kinds of objects located in similar directions. We suggest and calculate aerosol extinction coefficients from these RGB gray levels and the different distances of the three objects. To compare our measurement results, we also measure extinction coefficients using lidar. Finally, we find that there are meaningful and sensible correlations between these two measurements, with a correlation coefficient of 0.86. We measure the aerosol extinction coefficient at three different RGB wavelengths using the same method. From these aerosol extinction coefficients at three different wavelengths, we find that the Angstrom exponent ranges from 0.7 to 1.6 over a full daytime period. We believe that these Angstrom exponents can give important information about the size of the fine particles.

본 논문에서는 상용 카메라를 이용하여 미세먼지의 소산계수를 측정하기 위한 새로운 방법을 제안하였다. 하나의 주어진 영상에서 같은 방향에 놓인 동일한 종류의 물체에 대한 3개 이상의 화소점의 밝기를 이용하여 소산계수를 측정하였다. 계산에 사용하기 위해 선택된 화소에 해당하는 물체는 카메라와의 거리를 알고 있는 것으로 선택하였다. 카메라를 이용하여 측정한 미세먼지의 소산계수와의 비교를 위하여 라이다를 이용하여 소산계수를 측정하였다. 최종적으로 카메라를 이용하여 측정한 미세먼지의 소산계수와 라이다를 이용한 그것에는 신뢰할 수 있는 상관관계를 얻었으며, 약 0.86 정도의 값을 보였다. 같은 방법으로 카메라의 R, G, B 3센서의 유효파장에서 소산계수를 얻을 수 있다는 것을 보였으며, 이러한 3파장에서의 소산계수를 통하여 하루 동안의 옹스트롱 지수(Angstrom exponent) 변화를 얻었는데, 이 값은 0.7~1.6 범위에 존재한다는 것을 알 수 있었다. 이러한 지수는 입자의 크기와 관련된 중요한 정보로 사용할 수 있다.

Keywords

References

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