Gas Distribution Mapping and Source Localization: A Mini-Review

김태환,박인규 한국센서학회 2023 센서학회지 Vol.32 No.2

The significance of gas sensors has been emphasized in various industries and applications, owing to the growing significance of environmental, social, and governance (ESG) management in corporate operations. In particular, the monitoring of hazardous gas leakages and detection of fugitive emissions have recently garnered significant attention across several industrial sectors. As industrial workplaces evolve to ensure the safety of their working environments and reduce greenhouse gas emissions, the demand for high-performance gas sensors in industrial sectors dealing with toxic substances is on the rise. However, conventional gas-sensing systems have limitations in monitoring fugitive gas leakages at both critical and subcritical concentrations in complex environments. To overcome these difficulties, recent studies in the field of gas sensors have employed techniques such as mobile robotic olfaction, remote optical sensing, chemical grid sensing, and remote acoustic sensing. This review highlights the significant progress made in various technologies that have enabled accurate and real-time mapping of gas distribution and localization of hazardous gas sources. These recent advancements in gas-sensing technology have shed light on the future role of gas-detection systems in industrial safety.

An effective deep learning model for ship detection from satellite images

Aaqib Mehran,Samabia Tehsin,Muhammad Hamza 대한공간정보학회 2023 Spatial Information Research Vol.31 No.1

Detecting ships from satellite images is a challenging task in the domain of remote sensing. It is very important for security, traffic management and to avoid smuggling etc. SAR (Synthetic Aperture Radar) is mostly used technology for Maritime monitoring but now researchers are increasingly studying Optical Satellite Images based technologies. Image processing and Computer Vision techniques were previously used to detect ships. In this work, Convolutional Neural Network based approach is used to detect ships from the satellite imagery. Several Deep Learning models have been used and tested for this kind of task. We used state of art model Inception-Resnet that is pre trained on Image-Net dataset. We used the dataset "Ships in Satellite Imagery" to detect the presence of ships in an image. The dataset is publicly available on Kaggle. The results indicate adoption of transfer learning and data augmentation yields a successful detection of ships with an accuracy of more than 99%. Similarly, exploring different deep learning models for this task provide results with high accuracy for less training time.

Development of an Off-Axis TMA Telescope for Coastal Water Remote Sensing

전민우,현상원,배지용,정병준,오은송,강혁모,박영제,박찬필,김건희 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.17 No.5

A proto-model of an off-axis reflective fore-optics in a new hyperspectral sensor onboard a small unmanned aerial vehicle (UAV) is developed for low-altitude coastal remote sensing. In spite of the substantial advantages of off-axis optics over refractive or on-axis reflective optics, it is difficult to fabricate and align the mirrors in off-axis systems because of their asymmetric configurations. The fore-optics is designed by Korea Institute of Ocean Science & Technology (KIOST) as a three-mirror system including aspheric primary and secondary mirrors, with an entrance pupil diameter of 70 mm and F-ratio of 5.0. The off-axis mirror is fabricated by a single point diamond turning machine (SPDTM) with a form accuracy of 89.3 nm (RMS) and surface roughness of 7.2 nm (Ra). Coarse alignment of this three-mirror off-axis optical system is accomplished by using a designated base plate and a coordinate measuring machine. The optical performance is tested using the point spread function of the returned collimated beam of a Fizeau interferometer.

화산재입자의 고유 광학특성이 원격탐사 복사량에 미치는 민감도 분석

이권호 ( Kwon Ho Lee ),장은숙 ( Eun Suk Jang ) 대한원격탐사학회 2014 大韓遠隔探査學會誌 Vol.30 No.1

화산재입자의 굴절률과 산란 같은 고유 광학 특성으로 결정되는 분광학적 신호는 원격탐사 센서를 통하여 측정될 수 있지만, 화산 폭발 이후 생성된 화산재입자의 성분에 대한 굴절률에 관한 정보는 매우 제한적이었다. 따라서, 화산재입자의 원격탐사의 강건성을 개선하기 위하여 화산재입자와 복사전달 과정의 상호작용에 대한 정확한 이해가 필요하다. 본 연구에서는 화산재 주요 성분으로 알려진 화산성 안산암과 부석에 대한 입자 소산계수, 산란 위상함수, 비대칭 계수, 단산란 알베도 값을 정량화 하였다. 이러한 화산재입자의 고유 광학 특성값은 복사전달모델의 입력자료로 이용하여 다양한 에어러솔 광학두께(τ) 및 기하조건에서 원격탐사 센서(인공위성과 지상관측용)가 측정하는 이론적인 복사량과 화산재입자 특성의 관계를 분석하였다. 복사전달모델 분석결과, 대기권 최상층부에서 τ 에 대한 복사량의 변화율의 평균값은 안산암의 경우 부석보다 6배 정도 크게 나타났다. 지표에서 이러한 변화율은 τ<1인 경우 양의 상관관계를 보이지만, τ>1인 경우에는 음의 상관관계를 보였다. 그러나, 적외선 영역인 11 μm 에서는 차이가 매우 적게 나타났으며, 여기서 발생하는 복사량의 오차범위는 광학두께가 증가할수록 커지는 양상을 보이며, 다항 회귀함수로 표현될 수 있다. 이러한 결과는 원격 탐사 관측자료를 이용한 화산재 관측에 있어서 화산재의 정량적 분석에 도움이 될 것이다. Volcanic ash (VA) can be estimated by remote sensing sensors through their spectral signatures determined by the inherent optical property (IOP) including complex refractive index and the scattering properties. Until now, a very limited range of VA refractive indices has been reported and the VA from each volcanic eruption has a different composition. To improve the robustness of VA remote sensing, there is a need to understanding of VA - radiation interactions. In this study, we calculated extinction coefficient, scattering phase function, asymmetry factor, and single scattering albedo which show different values between andesite and pumice. Then, IOPs were used to analyze the relationship between theoretical remote sensed radiation calculated by radiative transfer model under various aerosol optical thickness (τ) and sun-sensor geometries and characteristics of VA. It was found that the mean rate of change of radiance at top of atmosphere versus τ is six times larger than in radiance values at 0.55 μm. At the surface, positive correlation dominates when τ<1, but negative correlation dominates when τ>1. However, radiance differences between andesite and pumice at 11 μm are very small. These differences between two VA types are expressed as the polynomial regression functions and that increase as VA optical thickness increases. Finally, these results would allow VA to be better characterized by remote sensing sensors.

A Mini Review of Recent Advances in Optical Pressure Sensor

이기훈,김현진,박인규 한국센서학회 2023 센서학회지 Vol.32 No.1

Innovative and advanced technologies, including robots, augmented reality, virtual reality, the Internet of Things, and wearable medical equipment, have largely emerged as a result of the rapid evolution of modern society. For these applications, pressure monitoring is essential and pressure sensors have attracted considerable interest. To improve the sensor performance, several new designs of pressure sensors have been researched based on resistive, capacitive, piezoelectric, optical, and triboelectric types. In particular, optical pressure sensors have been actively studied owing to their advantages, such as robustness to noise and remote sensing capability. Herein, a review of recent research on optical pressure sensors with self-powered sensing, remote sensing, high spatial resolution, and multimodal sensing capabilities is presented from the viewpoints of design, fabrication, and signal processing.

Design of Optical Biological Sensor for Phycocyanin Parameters Measurement using Fluorescence Technique

Sung Hwa Lee,Vinayagam Mariappan,Dong Chan Won,Myungsuk Ann,Seungyoun Yang 한국인터넷방송통신학회 2016 Journal of Advanced Smart Convergence Vol.5 No.2

Remote sensing and measurement are of paramount importance of providing information on the state of water quality in water bodies. The formation and growth of cyanobacteria is of serious concern to in land aquatic life forms and human life. The main cause of water quality deterioration stems from anthropogenic induced eutrophication. The goal of this research to quantify and determine the spatial distribution of cyanobacteria concentration in the water using remote sensing technique. The standard approach to measure water quality based on the direct measurement of the fluorescence of the chlorophyll a in the living algal cells and the same approach used to detect the phycobilin pigments found in blue- green algae (a.k.a. cyanobacteria), phycocyanin and phycoerythrin. This paper propose the emerging sensor design to measure the water quality based on the optical analysis by fluorescence of the phycocyanin pigment. In this research, we developed an method to sense and quantify to derive phycocyanin intensity index for estimating cyanobacteria concentrations. The development of the index was based on the reflectance difference between visible light band 620nm and 665nm. As a result of research this paper presents, an optical biological sensor design information to measure the Phycocyanin parameters in water content.

광학센서를 활용한 산림분야 원격탐사 활용기술

김은숙,원명수,김경민,박주원,이정수 대한원격탐사학회 2019 大韓遠隔探査學會誌 Vol.35 No.6

Nowadays, the utilization infrastructure of domestic satellite information is expanding rapidly. Especially, the development of agriculture and forestry satellite is expected to drastically change the utilization of satellite information in the forest sector. The launch of the satellite is expected in 2023. Therefore, NIFoS and academic experts in forest sectors have prepared “Special Issue on Forest Management Research using Optical Sensors and Remote Sensing Technologies” in order to understand new remote sensing technologies and suggest the future direction of forest research and decision-making. This special issue is focused on a variety of fields in forest remote sensing research, including forest resources survey, forest disaster detection, and forest ecosystem monitoring. The new research topics for remote sensing technologies in forest sector focuses on three points: development of new indicators and information for accurate detection of forest conditions and changes, the use of new information sources such as UAV and new satellites, and techniques for improving accuracy through the use of artificial intelligence techniques. 최근 국내 위성정보의 활용 기반이 급속히 확대되고 있다. 특히 2023년 발사 예정으로 사업이 추진 중인농림위성의 개발은 산림분야 위성정보 활용의 획기적인 전환을 가져올 전망이다. 국립산림과학원은 학계 전문가와 함께 산림 분야의 원격탐사 활용기술에 대해 점검하고 향후 나아갈 방향을 제시하기 위해 본 대한원격탐사학회지 산림분야 특별호를 추진하게 되었다. 본 논문에서는 향후 농림위성과의 연계성을 확보하기 위해 광학센서를 활용한 산림분야 원격탐사 활용기술을 중심으로 산림부문의 연구개발 현황을 파악하였다. 최근개발되고 있는 산림분야의 광학센서 활용기술은 크게 산림자원조사, 산림재해탐지, 산림생태계모니터링 등세 분야로 구분된다. 그리고 산림의 현황과 변화의 정확한 탐지를 위한 새로운 지표와 정보의 산출, 무인기 영상 및 신규 위성영상 등의 새로운 정보원 활용 방안 그리고 인공지능 기법의 활용을 통한 정확도 향상 기술에대한 연구가 중점적으로 추진되고 있다.

해양 미세플라스틱 모니터링을 위한 원격탐사 적용 가능성 검토

박수현 ( Suhyeon Park ),김창민 ( Changmin Kim ),정성우 ( Seongwoo Jeong ),장성간 ( Seonggan Jang ),김수빈 ( Subeen Kim ),하태정 ( Taejung Ha ),한경수 ( Kyung-soo Han ),양민준 ( Minjune Yang ) 대한원격탐사학회 2022 大韓遠隔探査學會誌 Vol.38 No.5

전 세계적으로 모든 해양 환경에서 발견되는 미세플라스틱이 환경 문제로 대두되면서 해양 미세플라스틱을 모니터링 하기 위한 연구가 국내외적으로 활발히 수행되고 있다. 최근 국외에서는 대규모의 실시간 관측이 가능한 원격탐사 기술을 해양 플라스틱 모니터링에 적용하기 위한 활발한 연구가 진행되고 있다. 그러나 국내에서 해양 미세플라스틱 원격탐사 관련 연구는 매우 미비한 실정이며 중대형 해양 플라스틱 원격탐사 연구만 일부 수행되고 있다. 본 논문에서는 국내와 국외에서 수행된 해양 플라스틱 원격탐사와 관련된 대표적인 연구사례를 통해 국내외 연구 동향을 파악하고, 해양 미세플라스틱 모니터링 시 원격탐사 기술의 적용 가능성에 대해 고찰하여 앞으로 국내에서의 연구 방향성에 대해 제안하고자 한다. Microplastics have arisen as a worldwide environmental concern, becoming ubiquitous in all marine compartments, and various researches on monitoring marine microplastics are being actively conducted worldwide. Recently, application of a remote detection technology that enables large-scale real-time observation to marine plastic monitoring has been conducted overseas. However, in South Korea, there is little information linking remote detection to marine microplastics and some field studies have demonstrated remote detection of medium- and large-sized marine plastics. This study introduces research cases with remote detection of marine plastics in South Korea and overseas, investigates potential feasibility of using the remote detection technology to marine microplastic monitoring, and suggests some future works to monitor marine microplastics with the remote detection.

드론 영상의 광학적 원격탐사 방법을 이용한 얕은 하천에서의 수심 추정에 관한 연구

최병길,나영우 한국측량학회 2022 한국측량학회지 Vol.40 No.6

The purpose of this study is to present a method for estimating water depth in shallow rivers using optical remotesensing techniques using drone images. In order to solve the disadvantages of existing bathymetry methods,bathymetry methods based on optical remote sensing have been recently studied, but research on environmentalconditions and data processing methods for bathymetry in shallow water areas is insufficient. Therefore, in this paper,we presented a water depth estimation formula in shallow rivers using drone images taken under various conditionsand directly surveyed bathymetric values using GNSS, and tried to verify the accuracy using checkpoints. As aresult, it was found that the water depth can be estimated more quickly and efficiently than the direct survey methodwhen the index is calculated and estimated with drone images in shallow rivers. In addition, when the reflected lightwas removed using a polarizing filter and high-resolution images were taken at noon without shadows, about 88%of them were within the acceptable range for bathymetry, and about 94% were within the acceptable range whenconverted to low resolution. Finally, when estimating the water depth using the optical remote sensing technique, itwas found that the accuracy was low at deep water depths, and errors could occur due to distortion of pixel valuesdue to water plants or shadows. 본 연구의 목적은 드론 영상으로 부터 광학적 원격탐사 기법을 적용하여 얕은 하천에서의 수심을 추정하기 위한 방법을 제시하는 데 있다. 기존의 수심측량 방법의 단점을 해결하기 위해 최근 광학적 원격탐사 기법에 따른 수심측량방법이 연구되고 있으나 얕은 수심 지역에서의 수심 측정을 위한 환경 조건과 자료처리 방법에 관한 연구가 미흡한실정이다. 따라서 본 논문에서는 다양한 조건에서 촬영한 드론 영상과 GNSS를 이용한 직접 측량된 수심 측정값을 이용하여얕은 하천에서의 수심 추정식을 제시하고, 검사점을 이용하여 정확도를 검증하고자 하였다. 그 결과 수심이 얕은 하천에서 드론 영상으로 지수를 산출하여 추정할 경우 직접 측량에 의한 방법보다는 좀 더 빠르고 효율적으로 수심을 추정할 수 있음을 알 수 있었다. 또한 편광필터를 이용하여 반사광을 제거하고, 그림자가 없는 정오에 고해상도로 촬영한 경우 약 88%가 수심측량 허용범위에 만족하고, 저해상도로 변환한 경우 약 94%가 허용범위에 만족하는 것을 알수 있었다. 마지막으로 광학적 원격탐사 기법을 이용한 수심을 추정할 경우 깊은 수심에서는 정확도가 낮고, 너울, 수초, 그림자 등으로 인한 화소값의 왜곡으로 인해 오차가 발생될 수 있음을 알 수 있었다.

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.