• Title/Summary/Keyword: point cloud model

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SURFACE RECONSTRUCTION FROM SCATTERED POINT DATA ON OCTREE

  • Park, Chang-Soo;Min, Cho-Hon;Kang, Myung-Joo
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.16 no.1
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    • pp.31-49
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    • 2012
  • In this paper, we propose a very efficient method which reconstructs the high resolution surface from a set of unorganized points. Our method is based on the level set method using adaptive octree. We start with the surface reconstruction model proposed in [20]. In [20], they introduced a very fast and efficient method which is different from the previous methods using the level set method. Most existing methods[21, 22] employed the time evolving process from an initial surface to point cloud. But in [20], they considered the surface reconstruction process as an elliptic problem in the narrow band including point cloud. So they could obtain very speedy method because they didn't have to limit the time evolution step by the finite speed of propagation. However, they implemented that model just on the uniform grid. So they still have the weakness that it needs so much memories because of being fulfilled only on the uniform grid. Their algorithm basically solves a large linear system of which size is the same as the number of the grid in a narrow band. Besides, it is not easy to make the width of band narrow enough since the decision of band width depends on the distribution of point data. After all, as far as it is implemented on the uniform grid, it is almost impossible to generate the surface on the high resolution because the memory requirement increases geometrically. We resolve it by adapting octree data structure[12, 11] to our problem and by introducing a new redistancing algorithm which is different from the existing one[19].

Development of An Inspection Method for Defect Detection on the Surface of Automotive Parts (자동차 부품 형상 결함 탐지를 위한 측정 방법 개발)

  • Park, Hong-Seok;Tuladhar, Upendra Mani;Shin, Seung-Cheol
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.22 no.3
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    • pp.452-458
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    • 2013
  • Over the past several years, many studies have been carried out in the field of 3D data inspection systems. Several attempts have been made to improve the quality of manufactured parts. The introduction of laser sensors for inspection has made it possible to acquire data at a remarkably high speed. In this paper, a robust inspection technique for detecting defects in 3D pressed parts using laser-scanned data is proposed. Point cloud data are segmented for the extraction of features. These segmented features are used for shape matching during the localization process. An iterative closest point (ICP) algorithm is used for the localization of the scanned model and CAD model. To achieve a higher accuracy rate, the ICP algorithm is modified and then used for matching. To enhance the speed of the matching process, aKd-tree algorithm is used. Then, the deviation of the scanned points from the CAD model is computed.

Underground Facility Survey and 3D Visualization Using Drones (드론을 활용한 지하시설물측량 및 3D 시각화)

  • Kim, Min Su;An, Hyo Won;Choi, Jae Hoon
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.40 no.1
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    • pp.1-14
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    • 2022
  • In order to conduct rapid, accurate and safe surveying at the excavation site, In this study, the possibility of underground facility survey using drones and the expected effect of 3D visualization were obtained as follows. Phantom4Pro 20MP drones have a 30m flight altitude and a redundant 85% flight plan, securing a GSD (Ground Sampling Distance) value of 0.85mm and 4points of GCP (Groud Control Point)and 2points of check point were calculated, and 7.3mm of ground control point and 11mm of check point were obtained. The importance of GCP was confirmed when measured with low-cost drones. If there is no ground reference point, the error range of X value is derived from -81.2 cm to +90.0 cm, and the error range of Y value is +6.8 cm to 155.9 cm. This study classifies point cloud data using the Pix4D program. I'm sorting underground facility data and road pavement data, and visualized 3D data of road and underground facilities of actual model through overlapping process. Overlaid point cloud data can be used to check the location and depth of the place you want through the Open Source program CloudCompare. This study will become a new paradigm of underground facility surveying.

An Accelerated Simulated Annealing Method for B-spline Curve Fitting to Strip-shaped Scattered Points

  • Javidrad, Farhad
    • International Journal of CAD/CAM
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    • v.12 no.1
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    • pp.9-19
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    • 2012
  • Generation of optimum planar B-spline curve in terms of minimum deviation and required fairness to approximate a target shape defined by a strip-shaped unorganized 2D point cloud is studied. It is proposed to use the location of control points as variables within the geometric optimization framework of point distance minimization. An adaptive simulated annealing heuristic optimization algorithm is developed to iteratively update an initial approximate curve towards the target shape. The new implementation comprises an adaptive cooling procedure in which the temperature change is adaptively dependent on the objective function evolution. It is shown that the proposed method results in an improved convergence speed when compared to the standard simulated annealing method. A couple of examples are included to show the applicability of the proposed method in the surface model reconstruction directly from point cloud data.

Phase Separations in Random Copolymer Solutions by Continuous Thermodynamics (연속열역학을 이용한 랜덤공중합체 용액의 상분리)

  • Sheo, Shin-Ho;Kim, Ki-Chang;Lee, Kwang-Rae
    • Journal of Industrial Technology
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    • v.18
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    • pp.277-287
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    • 1998
  • In this work continuous thermodynamics was adopted for describing the influence of copolymer polydispersity on phase separations in random copolymer solutions. Continuous themodynamic frameworks were formulated using the Flory-Huggin's excess Gibbs free energy model in which the concentration- and temperature-depentent terms of interaction parameter x were modified. Cloud-point curves and coexistence curves of poly(ethylene-vinylactate)/methylacetate solutions and poly(ehtylene-vinylacetate)/ethylacetate solutions were measured, and experimental data were fitted with theoretical relations formulated in this work. Calculated could-point curves were more good ageeable with experimental data than the modified Flory-Huggins's relations. Coexistence curves which were evaluated by using parameters of x estimated from experimental cloud-point curves, were found to coincide with experimental data.

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Segmentation and Classification of Lidar data

  • Tseng, Yi-Hsing;Wang, Miao
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.153-155
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    • 2003
  • Laser scanning has become a viable technique for the collection of a large amount of accurate 3D point data densely distributed on the scanned object surface. The inherent 3D nature of the sub-randomly distributed point cloud provides abundant spatial information. To explore valuable spatial information from laser scanned data becomes an active research topic, for instance extracting digital elevation model, building models, and vegetation volumes. The sub-randomly distributed point cloud should be segmented and classified before the extraction of spatial information. This paper investigates some exist segmentation methods, and then proposes an octree-based split-and-merge segmentation method to divide lidar data into clusters belonging to 3D planes. Therefore, the classification of lidar data can be performed based on the derived attributes of extracted 3D planes. The test results of both ground and airborne lidar data show the potential of applying this method to extract spatial features from lidar data.

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The Development of Point Heavy Rainfall Model Based on the Cloud Physics (구름 물리학을 토대로한 지점 호우모형 개발)

  • 이재형;선우중
    • Water for future
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    • v.25 no.4
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    • pp.51-59
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    • 1992
  • Recently the pysically based precipitation model was developed by Geogakakos and Bras(1984) for the storm event. This is a modified version of the model. In a different way from the model, in this paper, it is emphasized that the hyderometeor size distribution(HSD)is subject to rainfall intensity and effects on the productivity of precipitation. The to HSD functions are applied to the equation of the outflow after mass through the cloud top and base, products of rainfall rate at the ground level, storage of cloud layer. As an input we put the meterological data observed at Chonju in Korea in our models and adjust the parameters included in it. The result show that in the model there is significant deviation between the hourly calculated rainfall rate and the observed data, while it is very small in the our model based on the two HSD.

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Microsoft Kinect-based Indoor Building Information Model Acquisition (Kinect(RGB-Depth Camera)를 활용한 실내 공간 정보 모델(BIM) 획득)

  • Kim, Junhee;Yoo, Sae-Woung;Min, Kyung-Won
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.31 no.4
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    • pp.207-213
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    • 2018
  • This paper investigates applicability of Microsoft $Kinect^{(R)}$, RGB-depth camera, to implement a 3D image and spatial information for sensing a target. The relationship between the image of the Kinect camera and the pixel coordinate system is formulated. The calibration of the camera provides the depth and RGB information of the target. The intrinsic parameters are calculated through a checker board experiment and focal length, principal point, and distortion coefficient are obtained. The extrinsic parameters regarding the relationship between the two Kinect cameras consist of rotational matrix and translational vector. The spatial images of 2D projection space are converted to a 3D images, resulting on spatial information on the basis of the depth and RGB information. The measurement is verified through comparison with the length and location of the 2D images of the target structure.

3D Library Platform Construction using Drone Images and its Application to Kangwha Dolmen (드론 촬영 영상을 활용한 3D 라이브러리 플랫폼 구축 및 강화지석묘에의 적용)

  • Kim, Kyoung-Ho;Kim, Min-Jung;Lee, Jeongjin
    • Cartoon and Animation Studies
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    • s.48
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    • pp.199-215
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    • 2017
  • Recently, a drone is used for the general purpose application although the drone was builtfor the military purpose. A drone is actively used for the creation of contents, and an image acquisition. In this paper, we develop a 3D library module platform using 3D mesh model data, which is generated by a drone image and its point cloud. First, a lot of 2D image data are taken by a drone, and a point cloud data is generated from 2D drone images. A 3D mesh data is acquired from point cloud data. Then, we develop a service library platform using a transformed 3D data for multi-purpose uses. Our platform with 3D data can minimize the cost and time of contents creation for special effects during the production of a movie, drama, or documentary. Our platform can contribute the creation of experts for the digital contents production in the field of a realistic media, a special image, and exhibitions.

Heavy Rainfall Prediction by the Physically Based Model (물리 모형을 토대로한 호우 예측)

  • Lee, Jae Hyoung;Sonu, Jung Ho;Ceon, Ir Kweon;Hwang, Man Ha
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.14 no.5
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    • pp.1129-1136
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    • 1994
  • A point heavy rainfall process is physically modeled. It uses meteorological variables at the ground level as its inputs. The components of the model are parameterized based on well established observations and the previous studies of cloud physics. Particular emphasis is placed on the efficiency of accretion. So we adopt the modified skew-symmetric model for hydrometeor size distribution function that is suitable for the heavy rain cloud. The dominant parameters included in the model are estimated by the optimization technique. The rainfall intensity is predicted by the model with the medium values of estimated parameters.

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