무인항공기 기반 다중분광영상을 이용한 낙동강 Chlorophyll-a 및 녹조발생지수 분석

김흥민,최은영,장선웅,KIM, Heung-Min,CHOE, Eunyoung,JANG, Seon-Woong 한국지리정보학회 2022 한국지리정보학회지 Vol.25 No.1

Existing algal bloom monitoring is based on field sampling, and there is a limit to understanding the spatial distribution of algal blooms, such as the occurrence and spread of algae, due to local investigations. In this study, algal bloom monitoring was performed using an unmanned aerial vehicle and multispectral sensor, and data on the distribution of algae were provided. For the algal bloom monitoring site, data were acquired from the Mulgeum·Mae-ri site located in the lower part of the Nakdong River, which is the areas with frequent algal bloom. The Chlorophyll-a(Chl-a) value of field-collected samples and the Chl-a estimation formula derived from the correlation between the spectral indices were comparatively analyzed. As a result, among the spectral indices, Maximum Chlorophyll Index (MCI) showed the highest statistical significance(R²=0.91, RMSE=8.1mg/m³). As a result of mapping the distribution of algae by applying MCI to the image of August 05, 2021 with the highest Chl-a concentration, the river area was 1.7km², the Warning area among the indicators of the algal bloom warning system was 1.03km²(60.56%) and the Algal Bloom area occupied 0.67km²(39.43%). In addition, as a result of calculating the number of occurrence days in the area corresponding to the "Warning" in the images during the study period (July 01, 2021~November 01, 2021), the Chl-a concentration above the "Warning" level was observed in the entire river section from 12 to 19 times. The algal bloom monitoring method proposed in this study can supplement the limitations of the existing algal bloom warning system and can be used to provide information on a point-by-point basis as well as information on a spatial range of the algal bloom warning area.

위성 및 드론 영상을 이용한 해안쓰레기 모니터링 기법 개발

김흥민,박수호,한정익,예건희,장선웅,Kim, Heung-Min,Bak, Suho,Han, Jeong-ik,Ye, Geon Hui,Jang, Seon Woong 대한원격탐사학회 2022 大韓遠隔探査學會誌 Vol.38 No.6

This study proposes a marine debris monitoring methods using satellite and drone multispectral images. A multi-layer perceptron (MLP) model was applied to detect marine debris using Sentinel-2 satellite image. And for the detection of marine debris using drone multispectral images, performance evaluation and comparison of U-Net, DeepLabv3+ (ResNet50) and DeepLabv3+ (Inceptionv3) among deep learning models were performed (mIoU 0.68). As a result of marine debris detection using satellite image, the F1-Score was 0.97. Marine debris detection using drone multispectral images was performed on vegetative debris and plastics. As a result of detection, when DeepLabv3+ (Inceptionv3) was used, the most model accuracy, mean intersection over union (mIoU), was 0.68. Vegetative debris showed an F1-Score of 0.93 and IoU of 0.86, while plastics showed low performance with an F1-Score of 0.5 and IoU of 0.33. However, the F1-Score of the spectral index applied to generate plastic mask images was 0.81, which was higher than the plastics detection performance of DeepLabv3+ (Inceptionv3), and it was confirmed that plastics monitoring using the spectral index was possible. The marine debris monitoring technique proposed in this study can be used to establish a plan for marine debris collection and treatment as well as to provide quantitative data on marine debris generation.

무인항공기 및 다중분광센서를 이용한 하천부유쓰레기 탐지 기법 연구

김흥민,윤홍주,장선웅,정용현,Kim, Heung-Min,Yoon, HongJoo,Jang, SeonWoong,Chung, YongHyun 대한원격탐사학회 2017 大韓遠隔探査學會誌 Vol.33 No.5

본 연구는 무인항공기 및 다중분광센서를 이용한 부유쓰레기 탐지 알고리즘을 개발하고자 하였다. 또한 알고리즘을 적용하여 하천의 부유쓰레기 발생 범위를 산정하였다. 부유쓰레기 탐지 구간을 대상으로 무인항공기를 이용한 항공촬영을 통해 면적 계산이 가능한 정사영상을 생성하였으며, 분광조사를 수행하여 하천수, 스티로폼, 초목류 등의 분광학적 특성을 이용한 부유쓰레기 탐지 지수식을 산출하였다. 그리고 산출된 지수식을 이용한 센서의 밴드 조합을 통해 스티로폼을 비롯한 부유쓰레기를 탐지하였다. 탐지 지수식 적용 결과 정사영상 내 총 3지점에서 대량의 부유쓰레기 집적 구간이 확인되었으며, 탐지 대상 면적 중 집적구간을 포함한 3.6%에 해당하는 0.82 ha($8,200m^2$)에서 스티로폼과 초목류를 포함한 대량의 부유쓰레기가 발생한 것으로 추정되었다. This study aims to develop the floating debris detection algorithm using a Unmanned Aerial Vehicle (UAV) and multispectral sensors. In addition, the occurrence range of floating debris was estimated by applying the algorithm. An aerial photograph using an unmanned aerial vehicle was used to generate an orthoimage that can calculate the area. A spectrum survey of water, plants litter, polystyrene foam etc. was conducted. After obtaining spectroscopic characteristics of floating debris and water, the River Floating Debris (RFD) index was calculated. And we detected the floating debris through band combination of sensor using RFD. As a result of the RFD application, accumulation zone of floating debris was confirmed at three sites in the orthoimage. It was estimated that a lot of floating debris was accumulated at 0.82 ha ($8,200m^2$), which is corresponding to 3.6% including the accumulation zone.

무인항공영상을 활용한 낙동강 녹조 탐지

김흥민(Heung-Min Kim),장선웅(Seon-Woong Jang),윤홍주(Hong-Joo Yoon) 한국전자통신학회 2017 한국전자통신학회 논문지 Vol.12 No.3

하천에서 조류의 대량 번식은 녹조를 일으키고 수자원 안전에 대한 심각한 국가적 문제로 제기되고 있다. 따라서 깨끗한 용수를 확보하여 안정적인 수자원 공급을 위해 녹조로 인한 수질오염의 방재 기술 개발이 필요하다. 이에 본 연구는 무인항공기를 이용한 녹조 모니터링 기법을 적용하여 하천의 수질 관리 능력을 향상시키고자 하였다. 녹조현상이 빈번하게 발생하는 낙동강 중류의 도동 나루터를 대상으로 무인항공영상을 취득하였다. 또한 녹조시료 채취 및 수질검사를 통해 식물성 플랑크톤의 현존량을 조사하였다. 무인항공영상에 녹조 탐지 지수식을 적용한 결과와 식물성 플랑크톤의 현존량 간의 상관관계가 강한 양의 관계를 가지는 것으로 나타났다. 본 연구에서 제안된 원격탐사 기술은 하천 수질 오염 초기 대응 능력을 향상시킬 것으로 기대된다. The large breeding of algae in rivers has caused the algal bloom and has becoming a serious national problem for the safety of water sources. Therefore, in order to supply stable water resources through securing clean water, it is necessary to develop technology for prevention of water pollution caused by algal bloom. The purpose of this study is to improve the water quality management ability of river by applying the algal bloom detection technique using UAV. Unmanned aerial images were acquired for the Dodong in the middle region of the Nakdong River where algal bloom are frequent. In addition, the phytoplankton concentration was acquired through the sampling of algal bloom and the examination of water quality. Correlation between phytoplankton concentrations and the results of applying the algal bloom index to the Unmanned aerial images showed a strong positive correlation. The remote sensing method suggested in this study is expected to improve the initial response capability of river water pollution.

영암호 침적쓰레기 처리를 위한 침적쓰레기 분포 산정

김흥민(Kim, Heung-Min),장선웅(Jang, Seon-Woong),이진영(Lee, Jin Young),곽석남(Kwak, Seok Nam) 한국측량학회 2021 한국측량학회 학술대회자료집 Vol.2021 No.11

무인항공기 및 다중분광센서를 이용한 하천 녹조 모니터링

김흥민(Kim, Heung-Min),장선웅(Jang, Seon Woong) 한국측량학회 2021 한국측량학회 학술대회자료집 Vol.2021 No.11

무인항공기를 이용한 야적퇴비 적재량 산정 정확도 평가

김흥민(Heung-Min Kim),박수호(Su-Ho Bak),윤홍주(Hong-Joo Yoon),장선웅(Seon-Woong Jang) 한국전자통신학회 2021 한국전자통신학회 논문지 Vol.16 No.3

야적퇴비는 농경지의 작물 양분 공급원으로 가치를 가지는 반면, 강우 시 환경에 악영향을 미치는 오염원으로 작용하게 되며, 이에 대한 관리가 요구된다. 본 연구에서는 광범위 영상 취득 및 자동 경로 비행이 가능한 고정익 무인항공기를 이용한 야적퇴비 적재량 산출 정확도 분석 및 활용 가능성을 파악하고자 하였다. 야적퇴비 3개소에 대한 적재량 산출 정확도를 평가하고자 지상 LiDAR 측량 및 회전익 무인항공기를 이용한 정밀 측량을 수행하였으며, 고정익 무인항공기를 통해 취득된 적재량과 비교하였다. 지상 LiDAR를 기준으로 야적퇴비적재량 산출 비교 결과 회전익 기체의 오차율은 ±5 %, 고정익 기체의 오차율은 -15 ∼ -4 %로 추정하였다. 고정익 기체에서 산출된 1개의 야적퇴비 적재량이 약 –15%로 과소추정 하였으나 야적퇴비 적재량의 편차는 2.9 m3로 큰 차이는 없었다. 또한 고정익 무인항공기를 이용한 주기적인 모니터링 결과 대상 지역에 위치한 야적퇴비 적재량의 시계열 변동 파악할 수 있었다. 이러한 결과는 고정익 무인항공기를 이용한 넓은 범위의 대한 효율적인 야적퇴비 모니터링 및 농경지의 비점오염원 관리가 가능함을 제시하였다. While open-air compost has value as a source of nutrients for crops in agricultural land, it acts as a pollution that adversely affects the environment during rainfall, and management is required. In this study, it was intended to analyze the accuracy of calculating open-air compost volume using fixed-wing UAV (unmanned aerial vehicle) capable of acquiring a wide range of images and automatic path flights and to identify the possibility of utilization. In order to evaluate the accuracy of calculating the three open-air compost volume, ground LiDAR surveys and precision surveys using a rotary UAV were performed. and compared with the open-air compost volume acquired through a fixed-wing UAV. As a result of comparing the calculation of open-air compost volume based on the ground LiDAR, the error rate of the rotary-wing was estimated to be ±5%, and the error rate of fixed-wing was -15 ∼ -4%. one of three open-air compost volume calculated by fixed-wing was underestimated as about –15 %, but the deviation of the open-air compost volume was 2.9 m3, which was not significant. In addition, as a result of periodic monitoring of open-air compost using fixed-wing UAV, changes in the volume of open-air compost with time could be confirmed. These results suggested that efficient open-air compost monitoring and non-point pollutants in agricultural for a wide range using fixed-wing UAV is possible.

녹조 발생 수역에서 식물성 플랑크톤의 출현양상 및 광학적 특성

김흥민(Heung Min Kim),장선웅(Seon Woong Jang),윤홍주(Hong Joo Yoon) 한국생태공학회 2016 한국생태공학회지 Vol.5 No.1

The purpose of this study is to improve the water quality of river management ability by measuring water quality and reflectance in areas where algal bloom occur. The study obtained field data on the Dodong dock of Nakdong River on July 29th 2015, where algal bloom occurs frequently. Using spectrometer from green algal bloom occurred waters and obtained the reflectance of the algal bloom and clear water. Also, the researcher conducted field investigation and quantity analysis of 18 sites. In the investigated area, species composition of phytoplankton emerged in the investigated water showed to be 16 species of 5 classification group. Cyanophyceae and Chlorophyceae are dominant in study area. Among the Cyanophyceae, Microcystis sp. and Anabaena sp. appeared as dominant species. Optical characteristics of green algal bloom and clear water showed a different pattern at NIR band. In the case of clear water, while a constant reflectance, green algal bloom water showed 0.7 or more reflectance at NIR band. These field spectral data can be used for remote sensing of detect algal bloom.

하천 부유 쓰레기 상습 정체 구간의 수환경 및 생물다양성 영향 평가

김흥민(Heung Min Kim),박수호(Su Ho Bak),장선웅(Seon Woong Jang),곽석남(Seok Nam Kwak),윤홍주(Hong Joo Yoon) 한국전자통신학회 2018 한국전자통신학회 논문지 Vol.13 No.1

Investigation and policy related to floating debris are focused on water treatment or disposal costs, and water pollution caused by floating debris has not been evaluated. In this study, it was surveyed the water environment pollution on the stagnation zone by floating debris in Nakdong River basin of Busan Metropolitan City. The water quality of the constant stagnation zone had lower DO than that of the non-stagnation zone. COD and Chl-a showed similar concentrations in the both zones. As a result of the collecting net surveys which were kept floating during 3 months, the most abundant species(4 species) of arthropods appeared, and Chironomidae sp. is dominant. It was also resistant to the deteriorated water quality, and emerged as a Lepomis macrochirus on the stagnant waters with a slowly flow rate. 하천부유쓰레기 관련 조사 및 정책은 수거나 처리비용에 초점이 맞춰져있으며, 부유쓰레기로 인한 수환경 오염에 대한 평가는 진행되지 않았다. 이에 본 연구에서는 부산광역시에 위치한 낙동강 유역(금곡, 호포)의 부유쓰레기 집적구간에 대한 수환경 오염 조사를 진행하였다. 수질조사 결과 부유쓰레기 상습 정체 구간이 비정체 구간에 비해 낮은 DO 농도를 나타냈으며, COD와 Chl-a는 유사한 농도를 나타냈다. 상습 정체 구간에 약 3달간 부유 상태로 둔 포집조사 결과 절지동물문이 가장 많은 종(4종)이 출현하였으며, 깔따구류(Chironomidae sp.)가 우점하는 것으로 나타났다. 또한 질적 저하에 대한 내성이 강하며, 유속이 느리고 정체된 수역에서 주로 블루길(Lepomis macrochirus)이 출현하였다.

YOLOv8과 무인항공기를 활용한 고해상도 해안쓰레기 매핑

박수호,김흥민,김영민,이인지,박미소,김탁영,장선웅,Suho Bak,Heung-Min Kim,Youngmin Kim,Inji Lee,Miso Park,Tak-Young Kim,Seon Woong Jang 대한원격탐사학회 2024 大韓遠隔探査學會誌 Vol.40 No.2

Coastal debris presents a significant environmental threat globally. This research sought to improve the monitoring methods for coastal debris by employing deep learning and remote sensing technologies. To achieve this, an object detection approach utilizing the You Only Look Once (YOLO)v8 model was implemented to develop a comprehensive image dataset for 11 primary types of coastal debris in our country, proposing a protocol for the real-time detection and analysis of debris. Drone imagery was collected over Sinja Island, situated at the estuary of the Nakdong River, and analyzed using our custom YOLOv8-based analysis program to identify type-specific hotspots of coastal debris. The deployment of these mapping and analysis methodologies is anticipated to be effectively utilized in managing coastal debris.