• Aerospace Engineering and Technology
• /
• v.13 no.1
• /
• pp.37-43
• /
• 2014

The ground station which operates the LEO satellite performs monitoring state of health of the satellite, sending the commands for the imaging mission of receiving the images during about 10 minutes of contact time. To finish the planned procedure in limited contact time, specific level of autonomy is applied in the satellite and the ground system. For example, the attitude and orbit control logic has high level of autonomy because it must be operated alone for long period without operator intervention. On the other hand, the fault management logic has relatively low level of autonomy because of that failure detection and safing operation are performed on-board, whereas failure identification and recovery are on-ground operation. The level of autonomy of the satellite affects also the ground operation. The command set for mission operation is generated by ground system. If the satellite has higher level of autonomy, some of operation currently done on-ground can be performed on-board, so the ground operation can be simplified. In this paper, we discuss the level of autonomy and propose a concept for improving the level of autonomy of an LEO satellite.

• Journal of Korean Society for Geospatial Information Science
• /
• v.21 no.3
• /
• pp.11-17
• /
• 2013

With high social demands for the diverse utilizations of forest lands, the illegal forest land use changes have increased. We studied change detection technique to detect changes in forest land use using an object-oriented segmentation of RED bands differencing in multi-temporal aerial photographs. The new object-oriented segmentation method consists of the 5 steps, "Image Composite - Segmentation - Reshaping - Noise Remover - Change Detection". The method enabled extraction of deforested objects by selecting a suitable threshold to determine whether the objects was divided or merged, based on the relations between the objects, spectral characteristics and contextual information from multi-temporal aerial photographs. The results found that the object-oriented segmentation method detected 12% of changes in forest land use, with 96% of the average detection accuracy compared by visual interpretation. Therefore this research showed that the spatial data by the object-oriented segmentation method can be complementary to the one by a visual interpretation method, and proved the possibility of automatically detecting and extracting changes in forest land use from multi-temporal aerial photographs.

• Tunnel and Underground Space
• /
• v.33 no.4
• /
• pp.281-298
• /
• 2023

Continuous research efforts are being devoted to unmanned mobile platforms for lunar exploration. There is an ongoing demand for real-time information processing to accurately determine the positioning and mapping of areas of interest on the lunar surface. To apply deep learning processing and analysis techniques to practical rovers, research on software integration and optimization is imperative. In this study, a foundational investigation has been conducted on real-time analysis of virtual lunar base construction site images, aimed at automatically quantifying spatial information of key objects. This study involved transitioning from an existing region-based object recognition algorithm to a boundary box-based algorithm, thus enhancing object recognition accuracy and inference speed. To facilitate extensive data-based object matching training, the Batch Hard Triplet Mining technique was introduced, and research was conducted to optimize both training and inference processes. Furthermore, an improved software system for object recognition and identical object matching was integrated, accompanied by the development of visualization software for the automatic matching of identical objects within input images. Leveraging satellite simulative captured video data for training objects and moving object-captured video data for inference, training and inference for identical object matching were successfully executed. The outcomes of this research suggest the feasibility of implementing 3D spatial information based on continuous-capture video data of mobile platforms and utilizing it for positioning objects within regions of interest. As a result, these findings are expected to contribute to the integration of an automated on-site system for video-based construction monitoring and control of significant target objects within future lunar base construction sites.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.7 no.4
• /
• pp.9-17
• /
• 1997

This paper describes a monitoring system that examines water quality by analyzing behavioral patterns of fishes. The water quality inspection system (WQIS) captures color images of fishes with a CCD camera, extracts out fish regions from the images, and determines motion characteristics of fishes by computing consecutive frames. We define five types of measures that reflect behavioral patterns of fishes : floatness, fledness, clustemess, diffusiveness, and mobility. These measures are utilized when the system performs fuzzy inference to induce the conclusion about water quality. We believe that the proposed system can be a solution for securing clean water.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2020.06a
• /
• pp.71-71
• /
• 2020

최근 기후변화의 영향으로 극심한 가뭄과 홍수가 발생하고 기온 또한 꾸준히 상승하고 있으며, 이러한 변화에 대응하기 위해 전 세계에서 이산화탄소를 줄이고 국제 에너지 시장을 재구성하려는 시도가 꾸준히 이루어지고 있다. World Energy Outlook(2012)에 따르면 특히 에너지 시장에서 개발도상국의 수력분야 개발투자가 2035년까지 15,490억 달러에 이를 것으로 전망됨에 따라 국내에서 해외 수력발전사업에 적극적으로 나서고 있다. 그러나 국내와는 달리 댐 건설의 사전조사에 필요한 자료가 없거나 구축하는데 문제가 있어 손쉽게 구할 수 있는 자료로 사전에 수력발전 댐 적지를 조사할 수 있는 기술의 개발이 필요하다. 따라서 본 연구에서는 수력발전용 댐 위치 결정을 위한 예비 적지 분석 알고리즘을 개발하고, 분석 알고리즘에 위성영상자료인 30m 해상도의 ASTGTM(ASTER Global Digital Elevation Model)와 500m 해상도의 MCD12Q1(MODIS/Terra Aqua Land Cover) 토지피복자료를 사용하고자 한다. 예비 적지 분석 알고리즘은 DEM의 전처리, 하천망생성, 유역분할과 지형정보를 고려한 자동적지탐색과 댐 건설시 수몰면적에 따른 보상면적 산정 알고리즘을 포함하고 있으며 Python기반의 오픈소스 GIS로 구현되었다. 적지산정은 DEM으로부터 낙차, 도달시간, 내용적곡선과 같은 지형정보와 토지피복도를 통한 보상면적을 기반으로 순위를 매겨 사용자에게 최적의 위치들을 표출한다. 본 연구의 결과는 향후 해외 수력 댐 적지 예비분석 및 해외 수력산업 진출을 지원할 수 있을 것으로 기대된다.

• 한국지구과학회:학술대회논문집
• /
• 2010.04a
• /
• pp.38-39
• /
• 2010

낙뢰란 뇌운 속에서 분리 축적 된 음 (-)과 양 (+)의 전하 사이 또는 뇌운 속의 전하와 지면에 유도되는 전하 사이에서 발생하는 불꽃 방전을 말한다. 뇌운 안에는 이 불꽃 방전을 반복하기에 충분한 전하의 분리가 계속 일어나고 있는데, 그 결과 양전하 (+)는 구름의 상부에 넓게 분산되어 분포하고, 음전하 (-)는 주로 구름 하부에 분포한다. 이 때 음전하가 대지로 방전되어 발생하는 낙뢰를 부극성 (-)낙뢰, 양전하가 대지로 방전되어 발생하는 낙뢰를 정극성 (+)낙뢰라 한다. 낙뢰의 약 80%는 구름 내부 또는 구름 대 구름 사이에서 발생하고, 약 20%만이 구름과 지면 사이에서 발생하는데, 이러한 구름-지면 낙뢰 (Cloud-to-ground lightning)는 가장 위험하고 그 피해도 크다. 우리나라는 동아시아 몬순 기후의 영향으로 여름철에 대기가 불안정하여 낙뢰가 집중적으로 발생하며, 복잡한 지형과 해양의 영향으로 낙뢰현상의 공간적 변동도 크게 나타난다. 이러한 낙뢰는 최근으로 올수록 강도가 증가하고 있어 그 피해의 증가가 우려되기 때문에 낙뢰 발생 특성에 대한 연구가 필요하다. 본 연구에서는 낙뢰자료와 강수자료, 그리고 시 공간 분해능이 뛰어난 MTSAT-1R (Multi-functional Transport SATellite - 1 Replacement) 정지궤도 위성의 휘도온도를 이용하여 낙뢰 발생 시 강수 및 위성 휘도온도의 특성을 분석하고자 한다. 이러한 연구는 대류활동에 대한 정보 제공 뿐 아니라, 낙뢰 예측성 향상 및 재해 경감에도 활용될 수 있을 것이다. 본 연구에서는 2001년 기상청에 도입되어 운영 중인 신 낙뢰관측 시스템 (Total Lightning Detection System, TLDS)에서 관측된 낙뢰자료와 MTSAT-1R 위성에서 관측된 휘도온도 자료, 그리고 자동기상관측장비 (Automatic Weather System, AWS)에서 관측된 강수자료를 사용하였으며, 세 자료의 출처는 모두 기상청이다. 분석 기간은 2006년부터 2007년까지이며 우리나라에서 낙뢰발생 빈도가 여름철에 집중되어 나타나는 것을 고려하여 여름철 (6~8월) 낙뢰에 대해서만 분석하였다. 또한 낙뢰 발생 사례에 대하여 관측 효율이 90% 이상으로 알려진 위도 $33{\sim}39^{\circ}N$, 경도 $124{\sim}130^{\circ}E$ 영역에서 낙뢰발생시 강수 및 위성 휘도온도의 특성을 분석하였다. 사례는 낙뢰 발생 횟수가 많은 날을 중심으로 먼저 적외영상과 낙뢰영상을 정성적으로 분석한 후 뇌우의 지속시간이 긴 9개 사례를 선정하였다. MTSAT-1R 위성과 낙뢰자료 및 강수자료는 관측주기와 공간규모가 서로 다르기 때문에 세 자료를 함께 사용하기 위해서는 시 공간을 일치시키는 과정이 필요하다. 본 연구에서는 위성자료 관측시간(00분, 33분)과 AWS 지점 위 경도를 시 공간 일치를 위한 기준으로 사용하였다.

• Journal of KIISE:Software and Applications
• /
• v.27 no.1
• /
• pp.74-83
• /
• 2000

There is a rapid increase in the use of digital video information in recent years. Especially, user requires the environment which retrieves video from passive access to active access, to be more efficiently. we need to implement video retrieval system including video parsing, clustering, and browsing to satisfy user's requirement. In this paper, we first divide video sequence to shots which are primary unit for automatic indexing, using a hybrid method with mixing histogram method and pixel-based method. After the shot boundaries are detected, corresponding key frames can be extracted. Key frames are very important portion because they help to understand overall contents of video. In this paper, we first analyze camera operation in video and then select different number of key frames depend on shot complexity. At last, we compose panorama images from shots which are containing panning or tilting in order to provide more useful and understandable browsing environment to users.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.8A
• /
• pp.805-813
• /
• 2002

Document image should be classified into detailed regions as text, picture, table and etc through the geometric layout analysis if paper documents can be converted automatically into electronic documents. However, complexity of the document layout and variety of the size and density of a picture are the reason to make it difficult to analyze the geometric layout of the document images. In this paper, we propose the method which have a better performance of the region segmentation and classifications, and the line extraction in the table region than the commercial softwares and previous methods. The proposed method can segment the document into detailed regions by using connected components method even if its layout is complex. This method also classifies texts and pictures by using separable median filter even. Though their size and density are diverse, In addition, this method extracts the lines from the table adapting one dimensional median filter to the each horizontal and vertical direction, even though lines are deformed or texts attached to them.

• Proceedings of the IEEK Conference
• /
• 1999.06a
• /
• pp.619-622
• /
• 1999

This paper describes a new semi-automatic segmentation algorithm based on color information. Semi-automatic segmentation mainly consists of intra-frame segmentation and inter-frame segmentation. While intra-frame segmentation extracts video objects of interest from boundary information provided by the user and intensity information of the image, inter-frame segmentation partitions the image into the video objects and background by tracking the motion of video objects. For inter-frame segmentation, color information (Y, Cb and Cr) of the current frame can be used efficiently in order to find the exact boundary of the video objects. In this paper we propose a new region growing algorithm which can maximize the ability of region differentiation, while preserving features of each color component.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.24 no.1
• /
• pp.60-66
• /
• 1987

This paper proposes an automatic image segmentation system for machine vision. In this an algorithm using the topological property on the multidimensional feature space for thresholding each primary segment in the image without prior information is presented. Also an effective filter for the removal of regional noises in a code valued image which are artifacts of the thresholding is presented. This method also may be applied for image enhancement or classification, which we show the possibility and the efficiency through computer simulation.