• Title/Summary/Keyword: 위치 및 방향 센서

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Soundsource Localization and Tracking System of Intruder for Intelligent Surveillance System (지능형 감시 시스템 구축을 위한 침입자의 음원 위치 파악 및 추적 시스템)

  • Park, Jung-Hyun;Yeom, Hong-Gi;Jung, Bong-Gyu;Jang, In-Hun;Sim, Kwee-Bo
    • Journal of the Korean Institute of Intelligent Systems
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    • v.17 no.6
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    • pp.786-791
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    • 2007
  • In the place that its security is crucial, the necessity of system which can tract and recognize random person is getting more important. In this paper, we'd like to develop the invader tracking system which consists of the sound source tracking-sensor and the pan-tilt camera for wide-area guard. After detecting the direction of any sound with the sound source tracking-sensor at first, our system make move the pan-tilt camera to that direction and extract reference image from that camera. This reference image is compared and updated by the next captured image after some interval time. By keeping on it over again, we can realize the guard system which can tract an invader using the difference image and the result of another image processing. By linking home network security system, the suggested system can provide some interfacing functions for the security service of the public facilities as well as that of home.

Development of Collision Prevention System for Agricultural Unmanned Helicopter (LiDAR를 이용한 농업용 무인헬기 충돌방지시스템 개발)

  • Jeong, Junho;Gim, Hakseong;Lee, Dongwoo;Suk, Jinyoung;Kim, Seungkeun;Kim, Jingu;Ryu, Si-dae;Kim, Sungnam
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.44 no.7
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    • pp.611-619
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    • 2016
  • This paper proposes a collision prevention system for an agricultural unmanned helicopter. The collision prevention system consists of an obstacle detection system, a mapping algorithm, and a collision avoidance algorithm. The obstacle detection system based on a LiDAR sensor is implemented in the unmanned helicopter and acquires distance information of obstacles in real-time. Then, an obstacle mapping is carried out by combining the distance to the obstacles with attitude/location data of the unmanned helicopter. In order to prevent a collision, alert is activated to an operator based on the map when the vehicle approaches to the obstacles. Moreover, the developed collision prevention system is verified through flight test simulating a flight pattern aerial spraying.

A Study on High Speed Visible Light Communication System Using Non-orthogonal Multiple Modulation Scheme (비직교 다중변조 방식을 이용한 고속 가시광통신 시스템에 대한 연구)

  • Han, Doo-Hee;Lee, Kyu-Jin
    • Journal of Convergence for Information Technology
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    • v.10 no.2
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    • pp.32-38
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    • 2020
  • In this paper, we analyze the modulation scheme for high speed transmission in visible light communication system, and study non-orthogonal multiplexing, dimming level and transmission power ratio. Conventional visible light communication has a disadvantage in that it is difficult to multi-transmit to increase the transmission speed. Multi-transmission technique is necessary for high-speed transmission at the transmitter. Since general visible light communication has a limitation in multiple transmission, various researches for high-speed transmission have been conducted. In order to solve this problem, this paper proposes a multiple modulation scheme for high-speed visible light communication using non-orthogonal multiplex transmission scheme and a future research direction.

Waveform Simulation of Full-Waveform LIDAR (풀웨이브폼 라이다의 반사파형 시뮬레이션)

  • Kim, Seong-Joon;Lee, Im-Pyeong
    • Korean Journal of Remote Sensing
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    • v.26 no.1
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    • pp.9-20
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    • 2010
  • The LIDAR data can be efficiently utilized for automatic reconstruction of 3D models of objects on the terrain and the terrain itself. In this paper, we attempted to generate simulated waveforms of FW (Full-Waveform) LIDAR (LIght Detection And Ranging). We performed the geometric modeling of the sensor and objects, and the radiometric modeling of the waveform intensity. First, we compute the origins and directions of the sub-beams by considering the divergence effects of a laser beam. We then searched for the locations at which the sub-beams intersected with the objects, such as ground, buildings and trees. Finally, we generate the individual waveforms of the reflected sub-beams and the waveform of the entire beam by summing the individual ones. With the experimental results, we confirmed the waveforms were reasonably generated, showing the characteristics of the surfaces the beam interacted with.

A Quality-control Experiment Involving an Optical Televiewer Using a Fractured Borehole Model (균열모형시추공을 이용한 광학영상화검층 품질관리 시험)

  • Jeong, Seungho;Shin, Jehyun;Hwang, Seho;Kim, Ji-Soo
    • The Journal of Engineering Geology
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    • v.30 no.1
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    • pp.17-30
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    • 2020
  • An optical televiewer is a geophysical logging device that produces continuous high-resolution full-azimuth images of a borehole wall using a light-emitting-diode and a complementary metal-oxide semiconductor image sensor to provide valuable information on subsurface discontinuities. Recently, borehole imaging logging has been applied in many fields, including ground subsidence monitoring, rock mass integrity evaluation, stress-induced fracture detection, and glacial annual-layer measurements in polar regions. Widely used commercial borehole imaging logging systems typically have limitations depending on equipment specifications, meaning that it is necessary to clearly verify the scope of applications while maintaining appropriate quality control for various borehole conditions. However, it is difficult to directly check the accuracy, implementation, and reliability for outcomes, as images derived from an optical televiewer constitute in situ data. In this study, we designed and constructed a modular fractured borehole model having similar conditions to a borehole environment to report unprecedented results regarding reliable data acquisition and processing. We investigate sonde magnetometer accuracy, color realization, and fracture resolution, and suggest data processing methods to obtain accurate aperture measurements. The experiment involving the fractured borehole model should enhance not only measurement quality but also interpretations of high-resolution and reliable optical imaging logs.

Evaluation of Relative Corrosion Rate depending on Local Location and Installation of Structural Member in Steel Water Gate (강재 수문의 부재 위치 및 설치 방향에 따른 상대 부식속도 평가)

  • Ha, Min-Gyun;Jeong, Young Soo;Park, Seung hun;Ahn, Jin-Hee
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.23 no.7
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    • pp.16-24
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    • 2019
  • The corrosion amounts of steel structures can be different depending on their installation condition and height. Thus, their corrosion maintenance should be considered depending on installation conditions of local structural members. In this study, an atmospheric exposure test was conducted to evaluate the corrosion amount and the corrosion rate depending on the installation condition and height of a steel water gate using monitoring steel plates and corrosion environment measuring sensors. The mean corrosion depth was evaluated using the weight loss method and the galvanic corrosion current was measured by corrosion environment measuring sensors. Local corrosion rate of local structural member in steel water gate was estimated using measured mean corrosion depths and galvanic corrosion currents. From this measurement results, the corrosion damage in horizontal member of the cross beam was highly evaluated than those of other structural member as skin plate, etc. The relative difference in the corrosion rate of a local structural member could be highly affected by local corrosion environments of steel water gate members. Therefore, an appropriate maintenance method should be considered for local corrosion damages of local structural members determined by local corrosion environments of a steel water gate.

Observation Test of Field Surface Reflectance Using Vertical Rotating Goniometer on Tarp Surface and Grass (수직 축 회전형 측각기 제작 및 야외 지표면 반사도 관측 시험: 타프와 잔디에서)

  • Moon, Hyun-Dong;Jo, Euni;Kim, Hyunki;Cho, Yuna;Kim, Bo-Kyeong;Ahn, Ho-Yong;Ryu, Jae-Hyun;Cho, Jaeil
    • Korean Journal of Remote Sensing
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    • v.38 no.6_1
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    • pp.1207-1217
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    • 2022
  • 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.

3D Model Generation and Accuracy Evaluation using Unmanned Aerial Oblique Image (무인항공 경사사진을 이용한 3차원 모델 생성 및 정확도 평가)

  • Park, Joon-Kyu;Jung, Kap-Yong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.3
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    • pp.587-593
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    • 2019
  • The field of geospatial information is rapidly changing due to the development of sensor and data processing technology that can acquire location information. And demand is increasing in various related industries and social activities. The construction and utilization of three dimensional geospatial information that is easy to understand and easy to understand can be an essential element to improve the quality and reliability of related services. In recent years, 3D laser scanners are widely used as 3D geospatial information construction technology. However, 3D laser scanners may cause shadow areas where data acquisition is not possible when objects are large in size or complex in shape. In this study, 3D model of an object has been created by acquiring oblique images using an unmanned aerial vehicle and processing the data. The study area was selected, oblique images were acquired using an unmanned aerial vehicle, and point cloud type 3D model with 0.02 m spacing was created through data processing. The accuracy of the 3D model was 0.19m and the average was 0.11m. In the future, if accuracy is evaluated according to shooting and data processing methods, and 3D model construction and accuracy evaluation and analysis according to camera types are performed, the accuracy of the 3D model will be improved. In the point cloud type 3D model, Cross section generation, drawing of objects, and so on, it is possible to improve work efficiency of spatial information service and related work.

Object-based Building Change Detection Using Azimuth and Elevation Angles of Sun and Platform in the Multi-sensor Images (태양과 플랫폼의 방위각 및 고도각을 이용한 이종 센서 영상에서의 객체기반 건물 변화탐지)

  • Jung, Sejung;Park, Jueon;Lee, Won Hee;Han, Youkyung
    • Korean Journal of Remote Sensing
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    • v.36 no.5_2
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    • pp.989-1006
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    • 2020
  • Building change monitoring based on building detection is one of the most important fields in terms of monitoring artificial structures using high-resolution multi-temporal images such as CAS500-1 and 2, which are scheduled to be launched. However, not only the various shapes and sizes of buildings located on the surface of the Earth, but also the shadows or trees around them make it difficult to detect the buildings accurately. Also, a large number of misdetection are caused by relief displacement according to the azimuth and elevation angles of the platform. In this study, object-based building detection was performed using the azimuth angle of the Sun and the corresponding main direction of shadows to improve the results of building change detection. After that, the platform's azimuth and elevation angles were used to detect changed buildings. The object-based segmentation was performed on a high-resolution imagery, and then shadow objects were classified through the shadow intensity, and feature information such as rectangular fit, Gray-Level Co-occurrence Matrix (GLCM) homogeneity and area of each object were calculated for building candidate detection. Then, the final buildings were detected using the direction and distance relationship between the center of building candidate object and its shadow according to the azimuth angle of the Sun. A total of three methods were proposed for the building change detection between building objects detected in each image: simple overlay between objects, comparison of the object sizes according to the elevation angle of the platform, and consideration of direction between objects according to the azimuth angle of the platform. In this study, residential area was selected as study area using high-resolution imagery acquired from KOMPSAT-3 and Unmanned Aerial Vehicle (UAV). Experimental results have shown that F1-scores of building detection results detected using feature information were 0.488 and 0.696 respectively in KOMPSAT-3 image and UAV image, whereas F1-scores of building detection results considering shadows were 0.876 and 0.867, respectively, indicating that the accuracy of building detection method considering shadows is higher. Also among the three proposed building change detection methods, the F1-score of the consideration of direction between objects according to the azimuth angles was the highest at 0.891.

A Feasibility Study for Mapping Using The KOMPSAT-2 Stereo Imagery (아리랑위성 2호 입체영상을 이용한 지도제작 가능성 연구)

  • Lee, Kwang-Jae;Kim, Youn-Soo;Seo, Hyun-Duck
    • Journal of the Korean Association of Geographic Information Studies
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    • v.15 no.1
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    • pp.197-210
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    • 2012
  • The KOrea Multi-Purpose SATellite(KOMPSAT)-2 has a capability to provide a cross-track stereo imagery using two different orbits for generating various spatial information. However, in order to fully realize the potential of the KOMPSAT-2 stereo imagery in terms of mapping, various tests are necessary. The purpose of this study is to evaluate the possibility of mapping using the KOMPSAT-2 stereo imagery. For this, digital plotting was conducted based on the stereoscopic images. Also the Digital Elevation Model(DEM) and an ortho-image were generated using digital plotting results. An accuracy of digital plotting, DEM, and ortho-image were evaluated by comparing with the existing data. Consequently, we found that horizontal and vertical error of the modeling results based on the Rational Polynomial Coefficient(RPC) was less than 1.5 meters compared with the Global Positioning System(GPS) survey results. The maximum difference of vertical direction between the plotted results in this study and the existing digital map on the scale of 1/5,000 was more than 5 meters according as the topographical characteristics. Although there were some irregular parallax on the images, we realized that it was possible to interpret and plot at least seventy percent of the layer which was required the digital map on the scale of 1/5,000. Also an accuracy of DEM, which was generated based on the digital plotting, was compared with the existing LiDAR DEM. We found that the ortho-images, which were generated using the extracted DEM in this study, sufficiently satisfied with the requirement of the geometric accuracy for an ortho-image map on the scale of 1/5,000.