• Title/Summary/Keyword: 촬영조건의 정확도

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Evaluating the Accuracy of an OpenCV-Based Length Measurement Algorithm: The Impact of Checkerboard Type and Capturing Conditions (체커보드 종류 및 촬영조건에 따른 OpenCV 기반 길이측정 알고리즘 정확도 분석)

  • Kim, Hyeonmin;Kwon, Woobin;Kim, Harim;Kim, Hyungjun;Song, Seung Ho;Cho, Hunhee
    • Journal of the Korea Institute of Building Construction
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    • v.24 no.1
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    • pp.133-144
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    • 2024
  • The OpenCV-based length measurement algorithm is anticipated to be effective for length measurement inspection tasks, providing objective inspection outcomes. Nonetheless, there is a notable gap in research regarding the influence of various checkerboard types and capturing conditions on the algorithm's accuracy in real-world construction settings. Consequently, this study proposes a methodology employing an OpenCV-based length measurement algorithm and checkerboard for digital construction inspection tasks. The findings suggest that using a checkerboard with square sizes of A4 or larger, and 50mm or larger, is optimal for capturing distances and angles within 4m and 90°, respectively, when deploying the algorithm. These insights are anticipated to provide practical guidelines for professionals conducting digital-based length measurement inspections.

Establishment of Optimum Photo Condition for the Accurate Monitoring of Cultural Assets and Ground Facilities using Terrestrial Photographs (문화재와 지상시설물의 정밀점검을 위한 지상사진의 최적촬영조건 설정)

  • 손덕재
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.12 no.1
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    • pp.1-13
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    • 1994
  • The terrestrial phetogrammetry has the relative convenience of selecting the site of photo station in contrast with the aerial photogrammetry, and the flexibility in accuracy prediction of object point positioning. So it has the advantage in designing optimum photo taking system which can fulfill the required accuracy. For the convergent photos which are frequently used for the monitoring of cultural assets and ground facilities, almost all of the traditional studies for the optimum photo condition, both in theoretical or experimental, are basically depend on the symmetrical configuration at the normal direction to the center of the object. However, in many cases the surroundings of the object do not allow the normal photo direction or sufficient convergent angle, even more the object features are not always be seen as one panel like planar. In this paper, the accuracy variation of convergent photos for the multi-planar objects, which are composed by some orthogonal planes, are investigated to establish the optimum photo condition. The results of the accuracy analysis for the photo direction, convergent angle, as well as the object feature are expected to be utilized in system design of geometric configuration of convergent photos, which are adequate for the accurate monitoring of the objects, such as culural assets, facilities, precision instruments, deformation surveying, etc.

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Usefulness of Non-Invasive Measurement Tool on Performance Evaluation of Inverter Type X-ray Unit (인버터식 X선장치의 성능평가 시 비접속형 측정기의 유용성)

  • Kang, Se-Sik;Kim, Chang-Soo;Ko, Sung-Jin
    • Journal of radiological science and technology
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    • v.31 no.2
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    • pp.123-127
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    • 2008
  • Purpose: As the demand of a simple and precise method increases to evaluate the performance of the inverter type x-ray unit, we evaluated the usefulness of the recently-introduced X-ray Multi-Function Test Device (moldel : Xi (unfors)-prestige). Method: We compared the performance of X-ray Multi-Function Test Device (XMFTD) which is non-inveasive type device with the performance of Dynalyzer III that has been most widely used inveasive type measure device. Result: X-ray output dose was increased a little in the XMFTD, but both devices were below the performance evaluation standard, 0.002 in the output reproducibility. Linearity of XMFTD were below 0.1 which means that Dynalyzer III showed more excellency in linearity. As the the accuracy of exposure factor, 1.8 and 2 tube voltage, 2.01 and 2.3 tube current were measured. The exposure time was also measured by 0.01 sec ${\pm}10%$. Both devices were within the acceptance of performance evaluatioin standard. Conclusion: We proved the usefulness of X-ray Multi-Function Test Device (model: Xi (unfors)-prestige) to evaluated the performance on reproductibility and linearity of X-ray output and accuracy of exposure factor of inverter type unit.

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Accuracy Analysis on 3-D Coordinates According to the Variation of Photo Direction and of Convergent Angle in Close-Range Photogrammetry (근거리(近距離) 사진측량(寫眞測量)의 촬영방향(撮影方向)과 수렴각변화(收斂角變化)에 따른 3차원(三次元) 좌표결정(座標決定)의 정확도(正確度) 분석(分析))

  • Yeu, Bock Mo;Sohn, Duk Jae
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.9 no.4
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    • pp.125-133
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    • 1989
  • For convergent photos, which are now widely adopted for terrestrial facility survey, a number of experimental studies and theoretical studies on the developments of accuracy predictional model according to the convergent angle change have been accomplished. And such studies are basically depend on the symmetrical geometric configuration at the normal direction to the center of the object. However, in may cases of facility survey such as building facades, bridges, dam surfaces, relatively flat topography, etc., the object features are almost like planar, and frequently the surroundings do not allow the photo station at normal direction, and the sufficient convergent angle can be hardly achieved. Considering those points, in this study, the accuracy analysis on three dimensional coordinates according to the variations of photo direction and of convergent angle to the planar object were attempted, and the optimum geometric configurations at the normal, side-looking, and the most side-looking direction were investigated. The result through this study show that from normal direction to the side-looking direction angle ${\tau}=30^{\circ}$, the larger the convergent angle, the higher the accuracy, and in case that right photo is at the most side-looking direction, the better accuracy can be achieved according to the convergent angle increase up to $60^{\circ}$.

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The 3 Dimension Accuracy Analysis of Human Body Using the Digital Image (수치영상에 의한 인체형상의 3차원 정확도 분석)

  • Kang, Joon-Mook;Bae, Sang-Ho;Joo, Young-Eun
    • Journal of Korean Society for Geospatial Information Science
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    • v.5 no.2 s.10
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    • pp.111-119
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    • 1997
  • The precise measurement and the construction of analysis system for human body is very important in human engineering fields. As this study is about to the accuracy improvement of digital image for human body monitoring, we apply the optimum exposure condition which is decided through the accuracy analysis of digital images those are acquired at the various exposure station to the human body model. We acquired digital data in 1mm accuracy and carried out various spatial analyses. We expect tile results of this study to offer the fundamental source data for the human engineering fields.

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Comparison of SPOT5 Orthorectification Imagery Accuracy by DEM Scale (DEM축척에 따른 SPOT5영상의 정사보정 정확도 비교)

  • Lee Chong-Soo;Lee Sang-Ik;Lee Woo-Kyun;Jeon Seong-Woo;Kang Byung-Jin
    • Proceedings of the KSRS Conference
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    • 2006.03a
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    • pp.319-322
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    • 2006
  • 2002년 5월 촬영이 시작된 SPOTS 영상은 공간해상도가 2.5mX2.5m로 고해상도이면서도 촬영폭이 광역적이어서 다양한 활용이 가능하다. SPOT5영상을 보다 유용하게 활용하기 위해서는 단순 기하보정 보다는 높은 정확도를 얻을 수 있는 정사보정이 요구된다. 보정영상의 정확도에 영향을 미치는 요소로는 지형, GCP, DEM등이 있다. 본 연구에서는 다른 조건들은 동일하게 하고, 자료 구축에 많은 시간이 소요되는 DEM(수치표고모델)의 축척만을 달리하여 보정 영상의 정확도를 비교하였다. 그 결과 DEM의 축척 변화가 보정 영상에 미치는 영향은 미비한 것으로 나타났다. 따라서 작업의 효율성을 고려할 경우에 소축척의 DEM을 사용하는 것이 바람직하다.

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Development of an Integrated Traffic Object Detection Framework for Traffic Data Collection (교통 데이터 수집을 위한 객체 인식 통합 프레임워크 개발)

  • Yang, Inchul;Jeon, Woo Hoon;Lee, Joyoung;Park, Jihyun
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.18 no.6
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    • pp.191-201
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    • 2019
  • A fast and accurate integrated traffic object detection framework was proposed and developed, harnessing a computer-vision based deep-learning approach performing automatic object detections, a multi object tracking technology, and video pre-processing tools. The proposed method is capable of detecting traffic object such as autos, buses, trucks and vans from video recordings taken under a various kinds of external conditions such as stability of video, weather conditions, video angles, and counting the objects by tracking them on a real-time basis. By creating plausible experimental scenarios dealing with various conditions that likely affect video quality, it is discovered that the proposed method achieves outstanding performances except for the cases of rain and snow, thereby resulting in 98% ~ 100% of accuracy.

A Study on Precision of 3D Spatial Model of a Highly Dense Urban Area based on Drone Images (드론영상 기반 고밀 도심지의 3차원 공간모형의 정밀도에 관한 연구)

  • Choi, Yeon Woo;Yoon, Hye Won;Choo, Mi Jin;Yoon, Dong Keun
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.40 no.2
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    • pp.69-77
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    • 2022
  • The 3D spatial model is an analysis framework for solving urban problems and is used in various fields such as urban planning, environment, land and housing management, and disaster simulation. The utilization of drones that can capture 3D images in a short time at a low cost is increasing for the construction of 3D spatial model. In terms of building a virtual city and utilizing simulation modules, high location accuracy of aerial survey and precision of 3D spatial model function as important factors, so a method to increase the accuracy has been proposed. This study analyzed location accuracy of aerial survey and precision of 3D spatial model by each condition of aerial survey for urban areas where buildings are densely located. We selected Daerim 2-dong, Yeongdeungpo-gu, Seoul as a target area and applied shooting angle, shooting altitude, and overlap rate as conditions for the aerial survey. In this study, we calculated the location accuracy of aerial survey by analyzing the difference between an actual survey value of CPs and a predicted value of 3D spatial Model. Also, We calculated the precision of 3D spatial Model by analyzing the difference between the position of Point cloud and the 3D spatial Model (3D Mesh). As a result of this study, the location accuracy tended to be high at a relatively high rate of overlap, but the higher the rate of overlap, the lower the precision of 3D spatial model and the higher the shooting angle, the higher precision. Also, there was no significant relationship with precision. In terms of baseline-height ratio, the precision tended to be improved as the baseline-height ratio increased.

Evaluation of Usefulness of Assertive Devices to Improve the Accuracy in Skull lateral X-ray Projection (두개골 측방향 X-선 촬영에서 정확도 향상을 위한 촬영 보조 기구의 유용성 평가)

  • Bo-Seok Chang
    • Journal of the Korean Society of Radiology
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    • v.18 no.2
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    • pp.153-159
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    • 2024
  • In X-ray projection, Unskilled radiologists become skilled through fail exam. This causes the patient to be exposed to unnecessary radiation. In this study, pre-position unskilled radiologic technologist presented ways to improve clinical proficiency. presented a skull lateral x-ray projection practice method using visual, spatial, and assistive devices. In addition, the accuracy and usefulness of the use of assistive devices were evaluated. When X-ray images were taken based on learning, the rotational spacing, which indicates image distortion, was 7.85 ± 1.45 mm and the tiliting spacing was 4.84 ± 0.5 mm. When practicing using visual aids, the rotational spacing is 4.4 ± 0.76 mm and the inclination spacing is 3.01 ± 0.87 mm. using a spatial compensation device, the rotational spacing is 5.2 ± 0.69 mm and the tiliting spacing is 3.33 ± 0.61 mm. Skull lateral X-ray Image distortion caused by empirical photography practice decreased by 5.4%, but image distortion caused by tilting increased by 1.2%. When practicing using a visual assistive devices, the degree of rotational spacing by 40.1% and the tiliting spacing decreased by 30.7% compared to the empirical x-ray exposure practice. When using spatial assistive devices, the rotation interval was reduced by 41.7% and the tilting interval by 23.7% compared to conventional empirical x-ray exposure practice. Therefore, if an unskilled radiologist practices using visual and spatial aids,the accuracy will be improved in skull lateral x-ray projection.

Accuracy of Drone Based Stereophotogrammetry in Underground Environments (지하 환경에서의 드론 기반 입체사진측량기법의 정확도 분석)

  • Kim, Jineon;Kang, Il-Seok;Lee, Yong-Ki;Choi, Ji-won;Song, Jae-Joon
    • Explosives and Blasting
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    • v.38 no.3
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    • pp.1-14
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    • 2020
  • Stereophotogrammetry can be used for accurate and fast investigation of over-break or under-break which may form during the blasting of underground space. When integrated with small unmanned aerial vehicles(UAVs) or drones, stereophotogrammetry can be performed much more efficiently. However, since previous research are mostly focused on surface environments, underground applications of drone-based stereophotogrammetry are limited and rare. In order to expand the use of drone-based stereophotogrammetry in underground environments, this study investigated a rock surface of a underground mine through drone-based stereophotogrammetry. The accuracy of the investigation was evaluated and analyzed, which proved the method to be accurate in underground environments. Also, recommendations were proposed for the image acquisition and matching conditions for accurate and efficient application of drone-based stereophotogrammetry in underground environments.