수직 축 회전형 측각기 제작 및 야외 지표면 반사도 관측 시험: 타프와 잔디에서

문현동,조은이,김현기,조유나,김보경,안호용,류재현,조재일,Moon, Hyun-Dong,Jo, Euni,Kim, Hyunki,Cho, Yuna,Kim, Bo-Kyeong,Ahn, Ho-Yong,Ryu, Jae-Hyun,Cho, Jaeil 대한원격탐사학회 2022 大韓遠隔探査學會誌 Vol.38 No.6

Vegetation indices using the reflectance of selected wavelength, associating with the monitoring purpose such as identifying the progress of crop growth, on the vegetation canopy surface is widely used in the digital agriculture technology. However, the surface reflectance anisotropy can distort the true value of vegetation index related to the condition of surface, even though the surface property be unchanged. That causes difficulty to observe accurately crop growth on the monitoring system. In this study, a simple type goniometer was designed to measure the reflectance from the anisotropic surface according to various zeniths and azimuths of sun and viewing sensor in the field. On the tarp like as Lambertian surface, the reflectance of Blue, Green, Red, Near-Infrared band was similar to the tarps' reflectance properties. However, the reflectance was slightly overestimated in the cloudy day. The relative difference values of vegetation indices on grass were overestimated for the forward viewing and underestimated for the backward viewing. In addition, enhanced vegetation index (EVI) showed less sensitive according to the positions of sun and sensor viewing. Field observation with a goniometer will be helpful to understand the anisotropy characteristics on the vegetation surface.

BRDF 앙상블 모델을 이용한 고해상도 Sentinel-2 영상 보정

문현동,김보경,김경민,최수빈,조은이,안호용,류재현,최성원,조재일 대한원격탐사학회 2023 大韓遠隔探査學會誌 Vol.39 No.6

Vegetation indices based on selected wavelength reflectance measurements are used torepresent crop growth and physiological conditions. However, the anisotropic properties of the cropcanopy surface can govern spectral reflectance and vegetation indices. In this study, we applied anensemble of bidirectional reflectance distribution function (BRDF) models to high-resolution Sentinel-2 satellite imagery and compared the differences between correction results before and after reflectance. In the red and near-infrared (NIR) band reflectance images, BRDF-corrected outlier values appeared incertain urban and paddy fields of farmland areas and forest shadow areas. These effects were equallyobserved when calculating the normalized difference vegetation index (NDVI) and 2-band enhanced vegetation index (EVI2). Furthermore, the outlier values in corrected NIR band were shown in pixelsshadowed by mountain terrain. These results are expected to contribute to the development andimprovement of BRDF models in high-resolution satellite images.

열화상 카메라 활용을 위한 토양비료, 차광생육, 유전특성 차이 관련 작물생리 원격탐지

문현동,조유나,조은이,김현기,김보경,정회정,권동원,조재일,Moon, Hyun-Dong,Cho, Yuna,Jo, Euni,Kim, Hyunki,Kim, Bo-kyeong,Jeong, Hoejeong,Kwon, Dongwon,Cho, Jaeil 대한원격탐사학회 2022 大韓遠隔探査學會誌 Vol.38 No.6

The leaf temperature is principally regulated by the opening and closing of stomata that is sensitive to various kinds of plant physiological stress. Thus, the analysis of thermal imagery, one of remote sensing technique, will be useful to detect crop physiological condition on smart farm system and phenomics platform. However, there are few case studies using a thermal imaging camera on the agricultural application. In this study, three cases are presented: the effect of lime fertilizer on the rice, the different physiological properties of soybean under shading condition, and the screening of soybean breeds for salinity tolerance characteristic. The leaf temperature measured by thermal imaging camera on the three cases was used effectively to the physiological change and characteristics. However, the thermal imagery analysis requires considering the accuracy of measured temperature and the weather conditions that affects to the leaf temperature.

벼 출수기 이후 광합성이 등숙에 미치는 영향

문현동,조재일 전남대학교 농업과학기술연구소 2019 농업생명과학연구동향 Vol.57 No.-

Rice ripening rate is one of important yield component. The contribution to ripening rate was tested by removing the leaves after heading time. In addition, the ripening characteristics under high temperature condition were investigated in temperature gradient field chamber (TGFC). The ripening rate was dropped from 95.3% to 16.9% by removing leaves after heading. It means that the photosynthesis of leaves after heading is most great contributor on rice ripening. However, under high temperature, rice ripening rate was increased by infertility, but the contribution of leaves photosynthesis after heading was decreased. This information will be helpful to understand rice yield in future climate condition.

작물 가뭄스트레스 조기탐지 가능성 타진을 위한 서로 다른 종류의 식생지수 활용

문현동,조은이,조유나,김현기,김보경,이유현,정회정,권동원,조재일,Moon, Hyun-Dong,Jo, Euni,Cho, Yuna,Kim, Hyunki,Kim, Bo-kyeong,Lee, Yuhyeon,Jeong, Hoejeong,Kwon, Dongwon,Cho, Jaeil 대한원격탐사학회 2022 大韓遠隔探査學會誌 Vol.38 No.6

The irrigation schedule system using early detection of crop water stress is required to maintain crop production and save water resource. However, because previous studies focused on the crop under stress dominant condition, the crop physiological properties, which can be measured by remote sensing technique, on early crop water stress condition are not well known. In this study, the canopy temperature, MERIS Terrestrial Chlorophyll Index (MTCI), and Chlorophyll/Carotenoid Index (CCI) are observed on the soybeans given the early water stress using thermal imaging camera and hyperspectral camera. The increased canopy temperature and decreased MTCI are consist with the previous studies which are for the crop of stress dominant-sign. However, the CCI was increased contrary to expectation because it may faster the reduction of carotenoid than chlorophyll in early stage. These behaviors will be useful to not only develop the irrigation system but also using the early detection of crop stress.

Multi-coded Variable PPM for High Data Rate Visible Light Communications

문현동,정성윤 한국광학회 2012 Current Optics and Photonics Vol.16 No.2

In this paper, we propose a new modulation scheme called multi-coded variable pulse position modulation (MC-VPPM) for visible light communication systems. Two groups of signals (Pulse Width Modulation (PWM) and Pulse Position Modulation (PPM) groups) are multi-coded by orthogonal codes for transmitting data simultaneously. Then, each multi-level value of the multi-coded signal is converted to pulse width and position which results in not only an improved data rate, but also a processing gain in reception. In addition, we introduce average duty ratio and cyclic shift concepts in PWM through which dimming control for light illumination can be supported without any degradation in communication performance. Through simulation, we confirm that the proposed MC-VPPM shows a comparable BER curve and much greater achievable data rate than the conventional VPPM scheme using a visible light optical channel environment.

무인기 기반 다중분광 영상을 이용한 벼 쓰러짐 영역의 특성 분석

문현동 ( Hyun-dong Moon ),류재현 ( Jae-hyun Ryu ),나상일 ( Sang-il Na ),장선웅 ( Seon Woong Jang ),신서호 ( Seo-ho Sin ),조재일 ( Jaeil Cho ) 대한원격탐사학회 2021 大韓遠隔探査學會誌 Vol.37 No.5

벼 쓰러짐은 벼농사의 대표적인 기상재해 피해로써 강한 바람과 강우로 발생한다. 원격탐사 기법은 넓은 지역의 벼 쓰러짐을 효과적으로 탐지하기에 적절한 방법이다. 실제로 벼 쓰러짐은 벼 키가 최대인 생육 시기에 주로 발생하여 군락의 큰 구조적 변화를 불러오기 때문에 분광 반사도 차이를 야기한다. 따라서, 본고에서는 나주에 위치한 전남농업기술원의 2020년 태풍에 의한 논벼 피해를 444 nm부터 842 nm까지 10개 밴드로 구성된 카메라 영상으로 분석하였다. 드론 영상마다 벼 쓰러짐 피해를 받은 영역과 벼 쓰러짐 피해가 없는 영역으로 구분하여 벼 쓰러짐 영역의 분광 반사도 특성 차이와 식생 탐지에 주로 사용되는 식생지수인 NDVI (Normalized Difference Vegetation Index), NDRE (Normalized Difference Red Edge), CCI (Chlorophyll Carotenoid Index)의 변화를 살펴보았다. 반사도 값의 변화는 밴드6(668 nm)에서 가장 적었으며, 이를 중심으로 밴드 파장이 감소와 증가할수록 일반 논벼 보다 쓰러짐 영역 반사도가 커졌다. 또한, 쓰러진 벼를 묶어 세운 복구 지역은 대부분의 밴드에 걸쳐 반사도가 크게 감소함을 볼 수 있었다. NDVI와 NDRE는 벼 쓰러짐 영역에 대해 민감하게 반응하였으나, 그 반응 대상 및 정도는 서로 달랐다. 본 연구의 결과는 향후 드론과 위성을 이용한 벼 쓰러짐 피해 조사 알고리즘에 기여될 것으로 기대한다. Lodging rice is one of critical agro-meteorological disasters. In this study, the UAV-based multispectral imageries before and after rice lodging in rice paddy field of Jeollanamdo agricultural research and extension services in 2020 was analyzed. The UAV imagery on 14th Aug. includes the paddy rice without any damage. However, 4th and 19th Sep. showed the area of rice lodging. Multispectral camera of 10 bands from 444 nm to 842 nm was used. At the area of restoration work against lodging rice, the reflectance from 531 nm to 842 nm were decreased in comparison to un-lodging rice. At the area of lodging rice, the reflectance of around 668 nm had small increases. Further, the blue and NIR (Near-Infrared) wavelength had larger. However, according to the types of lodging, the change of reflectance was different. The NDVI (Normalized Difference Vegetation Index) and NDRE (Normalized Difference Red Edge) shows dome sensitivities to lodging rice, but they were different to types of lodging. These results will be useful to make algorithm to detect the area of lodging rice using a UAV.

가뭄과 폭염 조건에서 MTCI와 CCI를 이용한 수분 스트레스 평가

김경민,문현동,조은이,김보경,최수빈,이유현,이윤아,정회정,류재현,안호용,이성태,조재일 대한원격탐사학회 2023 大韓遠隔探査學會誌 Vol.39 No.6

The intensity of crop water stress caused by moisture deficit is affected by growth and heatconditions. For more accurate detection of crop water stress state using remote sensing techniques, it isnecessary to select vegetation indices sensitive to crop response and to understand their changes considering not only soil moisture deficit but also heat conditions. In this study, we measured the MERISterrestrial chlorophyll index (MTCI) and chlorophyll/carotenoid index (CCI) under drought and heatwave conditions. The MTCI, sensitive to chlorophyll concentration, sensitively decreased on nonirrigationconditions and the degree was larger with heat waves. On the other hand, the CCI, correlatedwith photosynthesis efficiency, showed less sensitivity to water deficit but had decreased significantlywith heat waves. After re-irrigation, the MTCI was increased than before damage and CCI became moresensitive to heat stress. These results are expected to contribute to evaluating the intensity of crop waterstress through remote sensing techniques.

영농형 태양광 시설 하부의 미기상 관측 자료: 보성에서 2019년 11월부터 2020년 5월까지 가을보리 재배기간 동안

조유나,윤창용,김현기,문현동,안규남,조재일 한국농림기상학회 2020 한국농림기상학회지 Vol.22 No.3

Agrivoltaic systems (AVS) is defined as combining farm-grown crops with photovoltaic panels (PV) installed several meters above the g round. Solar radiation (W /m2), photosynthetic photon flux density (PPFD, μmol/m2/s), air temperature (℃), vapor pressure (kPa), soil moisture (m3/m3), soil temperature (℃), wind direction (˚), and wind speed (m/s) were measured under the AVS in Boseong-gun during winter barley season. Data was collected by 5 minute interval. All data can download at Github site (https://github.com/chojaeil/AVS_Boseung). To gap-filling missing solar radiation data during about two weeks, the conversion coefficient from solar radiation to PPFD was estimated as 0.41. Further, according to the ratio of diffuse radiation to direct radiation, the maximum value among the twenty PPFD sensors under the AVS was related to the PPFD value of filed. 작물을 재배하는 동시에 전력 생산도 가능한 영농형 태양광 발전은 농업⋅농촌 분야와 재생에너지 산업 모두로부터 주목 받고 있다. 하지만, 그 역사가 짧은만큼 영농형 태양광 하부에서의 미기상 환경 변화에 대한 이해와 관측 방법론이 정립되지 않은 실정이다. 따라서 본고에서는 보성군에 설치된 영농형 태양광에서 2019년 11월 부터 2020년 5월까지의 보리 생육기간 동안 일사광, 광합성유효복사광, 기온, 습도, 토양습도⋅온도, 풍향⋅풍속을 5분 간격으로 측정하여 공개했다. 또한, 노지의 일사량 및 광합성유효복사량에 대한 약 13일 간의 자료 결손에 대해서는 가까운 기상청 관측 자료를 활용하거나 영농형 태양광 하부의 자료를 이용한 두 가지 경험적 메우기 방법을 제안하였다. 본고 자료가 영농형 태양광에 대한 농업적 평가에 다양하게 활용되기를 기대한다

마늘의 제초제 약해에 대한 구조적, 생화학적, 생리적 계열 식생지수 반응: 지상분광계 및 다중분광카메라를 활용하여

류재현 ( Jae-hyun Ryu ),문현동 ( Hyun-dong Moon ),조재일 ( Jaeil Cho ),이경도 ( Kyung-do Lee ),안호용 ( Ho-yong Ahn ),소규호 ( Kyu-ho So ),나상일 ( Sang-il Na ) 대한원격탐사학회 2021 大韓遠隔探査學會誌 Vol.37 No.6

다중분광카메라의 기술 개발로 인해 구조적 특성뿐만 아니라 생화학적, 생리적 특성을 가지는 식생지수를 다양한 공간 규모에서 활용할 수 있게 되었다. 이에 본 연구는 스트레스를 받은 노지작물을 대상으로 지상 초분광계 및 무인기 영상 기반 구조적, 생화학적, 생리적 계열의 식생지수 반응을 평가하였다. 마늘을 대상으로 서로 다른 생육시기에 고농도의 제초제를 살포하여 약해 처리하였으며, 정상 생육에 비해 지상부 건물중이 46.9~84.5% 감소하는 등 큰 피해가 나타났다. 제초제를 살포한 처리구에서 근적외선 분광반사도 값은 꾸준하게 감소하였으며, 구조적 식생지수에서 작물의 약해 피해가 명확하게 표현되었다. 생화학적 식생지수의 경우 일부 지수를 제외하고는 작물의 피해 상태를 표현하였으나 생리적 식생지수는 잎이 고사하고 드러나는 멀칭비닐의 영향으로 약해 피해를 해석하기에 어려움이 있었다. 제초제 살포 후 서로 다른 공간 규모에서 관측된 식생지수의 감소율 차이는 구조적 식생지수의 경우 평균적으로 2.3%로 나타났으며, 정규화 식생지수의 경우 1.3~4.1%의 분포를 보였다. 비록 생리적 식생지수가 작물 스트레스에 민감하다고 알려졌지만, 노지작물의 경우 작물 스트레스 종류와 재배 환경에 따라 적합한 식생지수를 활용하여야 한다는 것, 공간 규모에 따른 오차를 최소화하기 위해서는 정규화 식생지수를 활용해야 한다는 것을 확인하였다. The response of vegetation under the crop stress condition was evaluated using structural, biochemical, and physiological vegetation indices based on unmanned aerial vehicle (UAV) images and field-spectrometer data. A high concentration of herbicide was sprayed at the different growth stages of garlic to process crop stress, the above ground dry matter of garlic at experimental area (EA) decreased about 46.2~84.5% compared to that at control area. The structural vegetation indices clearly responded to these crop damages. Spectral reflectance at near-infrared wavelength consistently decreased at EA. Most biochemical vegetation indices reflected the crop stress conditions, but the meaning of physiological vegetation indices is not clear due to the effect of vinyl mulching. The difference of the decreasing ratio of vegetation indices after the herbicide spray was 2.3% averagely in the case of structural vegetation indices and 1.3~4.1% in the case of normalization-based vegetation indices. These results meant that appropriate vegetation indices should be utilized depending on the types of crop stress and the cultivation environment and the normalization-based vegetation indices measured from the different spatial scale has the minimized difference.