• Title/Summary/Keyword: Aerial exposure

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A Study on the Determination of the Minimum Number of Control Points for Aerial Photogrammetry Using Simulated GPS Data (GPS 데이터 적용을 위한 항공사진측량 최소 기준점수 결정에 관한 연구)

  • 김용일;배태석
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.14 no.1
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    • pp.89-95
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    • 1996
  • As an attempt to apply GPS technique to aerial photogrammetry, an effort is exerted to replace the ground control points that were necessary in the traditional aerial photogrammetry with the aerial control by measuring the position of the camera exposure. In this study, various situations are simulated to test the conditions that affect the positioning of the points in aerial photogrammetry for the use of GPS data. From the result of the simulations, the necessary conditions and the applicable values to produce a 1:1, 000 topographical map were suggested. In the case of a photo block consists of 104 photos, we found a minimum of six ground control points make acceptable accuracy under the condition of below $10\mu{m}$ image positional error and with the ground observations.

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SYNTHESIS OF STEREO-MATE THROUGH THE FUSION OF A SINGLE AERIAL PHOTO AND LIDAR DATA

  • Chang, Ho-Wook;Choi, Jae-Wan;Kim, Hye-Jin;Lee, Jae-Bin;Yu, Ki-Yun
    • Proceedings of the KSRS Conference
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    • v.1
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    • pp.508-511
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    • 2006
  • Generally, stereo pair images are necessary for 3D viewing. In the absence of quality stereo-pair images, it is possible to synthesize a stereo-mate suitable for 3D viewing with a single image and a depth-map. In remote sensing, DEM is usually used as a depth-map. In this paper, LiDAR data was used instead of DEM to make a stereo pair from a single aerial photo. Each LiDAR point was assigned a brightness value from the original single image by registration of the image and LiDAR data. And then, imaginary exposure station and image plane were assumed. Finally, LiDAR points with already-assigned brightness values were back-projected to the imaginary plane for synthesis of a stereo-mate. The imaginary exposure station and image plane were determined to have only a horizontal shift from the original image's exposure station and plane. As a result, the stereo-mate synthesized in this paper fulfilled epipolar geometry and yielded easily-perceivable 3D viewing effect together with the original image. The 3D viewing effect was tested with anaglyph at the end.

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Change of Skin Mucus Cells Related to Aerial Exposure of Misgurnus mizolepis (Cobitidae) Dwelling in a Rice Field (논에 서식하는 미꾸라지, Misgurnus mizolepis의 공기노출에 의한 피부 점액세포의 변화)

  • Oh, Min-Ki;Park, Jong-Young
    • Korean Journal of Ichthyology
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    • v.23 no.1
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    • pp.70-74
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    • 2011
  • During the winter, the rice field-dwelling muddy loach Misgurnus mizolepis is buried in burrows constructed of mud and are subjected to exposure to air at times of shortage of water. To investigate the environmental factors that lead to changes of the skin mucus cells of the muddy loach in rice fields, we carried out an experiment where we artificially exposure the fish to air, duplicating as close as possible winter conditions in nature. During the summer, a water tank containing M. mizolepis was filled with mud, and the water was allowed to evaporate. After a month of evaporation, the loach constructed burrows similar to those in a winter rice field. The epidermis in the experimental fish was mostly occupied by large elongated mucus cells, whose numbers drastically increased in all observed regions of the dorsum, lateral region, and the occiput. Such features are typically seen in fishes in wild habitats during the winter season.

A Study of Railway Bridge Automatic Damage Analysis Method Using Unmanned Aerial Vehicle and Deep Learning-based Image Analysis Technology (무인이동체와 딥러닝 기반 이미지 분석 기술을 활용한 철도교량 자동 손상 분석 방법 연구)

  • Na, Yong Hyoun;Park, Mi Yeon
    • Journal of the Society of Disaster Information
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    • v.17 no.3
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    • pp.556-567
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    • 2021
  • Purpose: In this study, various methods of deep learning-based automatic damage analysis technology were reviewed based on images taken through Unmanned Aerial Vehicle to more efficiently and reliably inspect the exterior inspection and inspection of railway bridges using Unmanned Aerial Vehicle. Method: A deep learning analysis model was created by defining damage items based on the acquired images and extracting deep learning data. In addition, the model that learned the damage images for cracks, concrete and paint scaling·spalling, leakage, and Reinforcement exposure among damage of railway bridges was applied and tested with the results of automatic damage analysis. Result: As a result of the analysis, a method with an average detection recall of 95% or more was confirmed. This analysis technology enables more objective and accurate damage detection compared to the existing visual inspection results. Conclusion: through the developed technology in this study, it is expected that it will be possible to analysis more accurate results, shorter time and reduce costs by using the automatic damage analysis technology using Unmanned Aerial Vehicle in railway maintenance.

Effects of Atmospheric Ozone on the Rice Blast Pathogen Pyricularia grisea

  • Hur, Jae-Seoun;Kim, Ki-Woo;Kim, Pan-Gi;Yun, Sung-Chul;Park, Eun-Woo
    • The Plant Pathology Journal
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    • v.16 no.1
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    • pp.19-24
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    • 2000
  • The direct effects of acute $\textrm{O}_3$ on the growth, sporulation and infection of Pyricularia grisea, rece blast pathogen, were investigated to understand the interactions between ozone and the pathogen. Acute exposure of 200 nl $\textrm{l}^{-1}$ ozone for 8 h significantly reduced conidia germination on water atar. Ozone exposure of 200 nl $\textrm{l}^{-1}$ for 8h per day for 5 days had no effect on increase in colony diameter, but severely damaged actively growing aerial mycelia. However, the damage to mycalia was recovered during the following 16 h exposure of unpolluted air. Conidial production was also stimulated by the acute ozone exposure for 5 days. The conidia exposed to the acute ozone for 5 days normally germinates but slightly reduce appressoria formation on rice leaf. However, the conidia produced by artificial stimulation under the same ozone concentration for 10 days showed significant reduction in appressorea for mation on a hydrophobic film. This study suggests that the acute ozone could ingibit appressoria formation as well as vegetative growth of the pathogen, resulting in decrease in rece blast development in the field during summer when high ozone episodes could occur occasionally.

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Acquisition of Subcentimeter GSD Images Using UAV and Analysis of Visual Resolution (UAV를 이용한 Subcentimeter GSD 영상의 취득 및 시각적 해상도 분석)

  • Han, Soohee;Hong, Chang-Ki
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.35 no.6
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    • pp.563-572
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    • 2017
  • The purpose of the study is to investigate the effect of flight height, flight speed, exposure time of camera shutter and autofocusing on the visual resolution of the image in order to obtain ultra-high resolution images with a GSD less than 1cm. It is also aimed to evaluate the ease of recognition of various types of aerial targets. For this purpose, we measured the visual resolution using a 7952*5304 pixel 35mm CMOS sensor and a 55mm prime lens at 20m intervals from 20m to 120m above ground. As a result, with automatic focusing, the visual resolution is measured 1.1~1.6 times as the theoretical GSD, and without automatic focusing, 1.5~3.5 times. Next, the camera was shot at 80m above ground at a constant flight speed of 5m/s, while reducing the exposure time by 1/2 from 1/60sec to 1/2000sec. Assuming that blur is allowed within 1 pixel, the visual resolution is 1.3~1.5 times larger than the theoretical GSD when the exposure time is kept within the longest exposure time, and 1.4~3.0 times larger when it is not kept. If the aerial targets are printed on A4 paper and they are shot within 80m above ground, the encoded targets can be recognized automatically by commercial software, and various types of general targets and coded ones can be manually recognized with ease.

Analysis of the Changes for Natural Environment by Geo-Spatial Information Database of Aerial Photo (항공사진의 지형공간정보 자료기반에 의한 자연환경변화의 분석)

  • Kang, In-Joon;Kwak, Jae-Ha;Park, Kie-Tae
    • Journal of Korean Society for Geospatial Information Science
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    • v.1 no.2 s.2
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    • pp.159-166
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    • 1993
  • Decrease of forest is seriously caused by urbanization. Photographic interpretation is the act of examining photographic images for the purpose of identifying objects and judging their significance. A systematic study of aerial photographs usually involves a consideration of the basic characteristics of photographic images. Seven of these characteristics are shape, size, pattern, shadow, tone, texture, and site. Aerial photographs contain a detailed record of the ground at the time of exposure. Authors blow the changes of natural environment by database for interpretation of aerial photo. In this paper, authors choose the Pusan National University located at the Kum-Joung Koo, Pusan as model area. Ten year of interval in 1980 and 1990, authors know the rate of forest decreasing is approximately 41 percents and the necessity of the protection of foreast. Authors suggest the combination of construction and protection of environment.

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A Study on Position and Induced Voltage of ADSS Using CSM (CSM을 이용한 ADSS유도전압 해석 및 위치선정에 관한 연구)

  • Myung, S.H.;Lee, B.Y.;Lee, G.C.;Lee, J.B.;Ha, T.H.;Joo, M.N.
    • Proceedings of the KIEE Conference
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    • 1997.07e
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    • pp.1654-1656
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    • 1997
  • Tracking currents related to field exposure for ADSS in T/L is of importance. At phase-ta-phase voltage in excess of 100 kV self-supporting aerial cables with solid insulation tend to suffer damage in regions close to the tower. The damage can be put down to surface tracking currents resulting from different degrees of surface contamination and moisture. Main characteristic of this exposure is the induced voltage analysis and position of ADSS. For complicated calculation of induced voltage on ADSS, this paper described an effective numerical calculation method based on CSM. The proposed methods are applied to 275 kV T/L of Malaysia.

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Effect on Qualities of Italic as the Degree of Sunlight Exposure after Harvest (수확 후 광 노출이 삼백초 품질변화에 미치는 영향)

  • Kim In-Jae;Kim Min-Ja;Yun Tae;Park Sung-Gue;Lee Woo-Young;Hong Seong-Su;Hwang Bang-Yeon;Nam Sang-Young
    • Korean Journal of Plant Resources
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    • v.18 no.3
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    • pp.505-511
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    • 2005
  • This study was carried out to obtain the basic information for quality changes according to degree of exposed sunlight after harvest of aerial part in Saururus chinensis Baill. Top part harvested was exposed to sunlight from 0 to 3 hours with 1-hour interval, and was dried at $50^{\circ}C$ hot air. The values were higher at shorter time of sunlight exposure, while the opposite is the true to the a values. The b and c values were high at 2-hour exposure before drying. Those were higher at shorter time of sunlight exposure after drying, but showed opposite tendency in tang-jeon. The contents of rutin and quercitrin, and astringency were greater at shorter time of sunlight exposure. Preference of quality and tang-jeon showed similar tendency with those.

Image Resampling for Epipolar Geometry in Digital Photogrammetry (數値寫眞測量에 있어서 epipolar 幾何狀態를 形成하기 위한 映像再配列)

  • Yeu, Bock-Mo;Youn, Kyung-Chul;Jeong, Soo
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.10 no.2
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    • pp.25-30
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    • 1992
  • Most algorithms in computer vision and digital photogrammetry assume that digital stereo pairs are registered in epipolar geometry. But, an aerial stereo pair is not likely to be in epiplar geometry since the attitude of the camera at the instant of exposure is different at every exposure station. In this paper, stereo digital imagery is obtained from aerial stereo pair by scanner. Then procesure to resample the digital imagery to epipolar geometry using exterior orientation elements after absolute orientation is described. As a result, a stereo imagery in epipolar geometry is produced from stereo digital imagery. Epipolar imagery in this paper is applied to the image matching method by digital image correlation technique. Then, a digital elevation model is produced from the result of image matching. The digital elevation model in this paper is compared to the other digital elevation model produced by analytical plotter. As a result, an economical method to generate digital elevation model is presented.

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