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A Study of the Characteristics of Highly Spatially Resolved CW-laser-based Aerosol Lidar

고공간분해능 연속 광원을 이용한 미세먼지 라이다의 신호 특성에 관한 연구

  • Sim, Juhyeon (Division of Earth Environmental System Science, Pukyong National University) ;
  • Kim, Taekeong (Division of Earth Environmental System Science, Pukyong National University) ;
  • Ju, Sohee (Division of Earth Environmental System Science, Pukyong National University) ;
  • Noh, Youngmin (Department of Environmental Engineering, Pukyong National University) ;
  • Kim, Dukhyeon (School of Basic Science, Hanbat National University)
  • 심주현 (부경대학교 지구환경시스템과학부 환경공학전공) ;
  • 김태경 (부경대학교 지구환경시스템과학부 환경공학전공) ;
  • 주소희 (부경대학교 지구환경시스템과학부 환경공학전공) ;
  • 노영민 (부경대학교 환경공학과) ;
  • 김덕현 (한밭대학교 기초과학부)
  • Received : 2021.11.15
  • Accepted : 2021.11.25
  • Published : 2022.02.25

Abstract

In this study we introduce a new method for high-spatial-resolution continuous wave (CW) aerosol lidar that has a high spatial resolution in the near field and a low spatial resolution at long distances. A normal lidar system uses a nanosecond-pulse laser and measures the round-trip TOF between the aerosol and laser to obtain range resolution. In this study, however, we propose a new type of spatially resolving aerosol lidar that uses laser-scattering images. Using a laser-light-scattering image, we have calculated the distance of each scattering aerosol image for a given pixel, and recovered the short-range aerosol extinction. For this purpose, we have calculated the distance image and the contribution range of the aerosol to the given one-pixel image, and finally we have calculated the extinction coefficients of the aerosol with range-resolved information. In the case of traditional aerosol lidar, we can only obtain the aerosol extinction coefficients above 400 m. Using our suggested method, it was possible to extend the range of the extinction coefficient lower then several tens of meters. Finally, we can remove the unknown short-range region of pulsed aerosol lidar using our method.

본 연구에서는 고가의 일반 펄스 레이저 없이 비교적 근거리에서 강한 거리 분해능을 지니며, 원거리에서도 공간 분해능을 지닌 연속광원 레이저를 이용한 미세먼지 라이다를 제안한다. 일반적인 라이다 시스템은 짧은 펄스의 레이저를 사용하고, 특정 거리 사이의 time-of-flight (TOF) 왕복시간을 측정하여 거리 정보를 얻고 있으나, 본 연구에서는 상용 카메라와 연속광 레이저 빔을 조사하여 얻은 영상을 사용하여 공간 분해능을 얻는 새로운 에어로졸 라이다를 소개한다. 본 연구에서는 라이다 신호와 함께 얻은 레이저의 이미지를 사용하여 주어진 하나의 화소에 해당하는 산란 에어로졸까지의 거리와 그 화소에 기여하는 에어로졸의 범위를 계산하였다. 이러한 거리와 기여 범위를 사용하여 거리 분해능을 갖는 에어로졸의 소멸계수를 계산하였으며, 기존 에어로졸 라이더의 경우 400 m 이상에서만 에어로졸 소산계수를 얻을 수 있었지만 제안 된 방법과 주어진 카메라의 조건을 사용하면 수십 미터 이하까지 그 소산계수를 얻을 수 있음을 알 수 있었다.

Keywords

Acknowledgement

이 논문은 2019년도 한밭대학교 대학회계 연구비를 지원받아 작성되었음.

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