• Journal of the Korea Computer Graphics Society
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• v.30 no.3
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• pp.1-8
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• 2024

We present a novel algorithm for creating 2D maps tailored for autonomous navigation within orchards. Recognizing that fruit trees in orchards are typically aligned in rows, our primary goal is to accurately detect these tree rows and project this information onto the map. Initially, we propose a simple algorithm that recognizes trees from point cloud data by analyzing the spatial distribution of points. We then introduce a method for detecting fruit tree rows based on the positions of recognized fruit trees, which are integrated into the 2D orchard map. Validation of the proposed approach was conducted using real-world orchard point cloud data acquired via LiDAR. The results demonstrate high tree detection accuracy of 90% and precise tree row mapping, confirming the method's efficacy. Additionally, the generated maps facilitate the development of natural navigation paths that align with the orchard's layout.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.19 no.1
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• pp.77-83
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• 2001

To product the map by terrestrial photogrammetry method, a few rather nuisance stereo image acquiring processing and plot using expensive analytical instruments have to be performed. In this study, plot was made by acquiring and rectification image using simple method rather than above it. For this, geometry rectification system was constructed for the generation of single ortho-image analysis. and these ortho-images of architecture were made and analysed by appling various warping methods. As a result, the performance of single image analysis could be estimated, and it is expected that the application of this is possible to various non-topographic photogrammetry.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.5
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• pp.464-474
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• 2003

Ultrasonic imaging of 3-D structures for nondestructive evaluation must provide readily recognizable images with enough details to clearly show various flaws that may or may not be present. Typical flaws that need to be detected are miniature cracks, for instance, in metal pipes having aged over years of operation in nuclear power plants; and these sub-millimeter cracks or flaws must be depicted in the final 3-D image for a meaningful evaluation. As a step towards improving conspicuity and thus detection of flaws, we propose a pulse-echo ultrasonic imaging technique to generate various 3-D views of the 3-D object under evaluation through strategic scanning and processing of the pulse-echo data. We employ a 2-D Wiener filter that filters the pulse-echo data along the plane orthogonal to the beam propagation so that ultrasonic beams can be sharpened. This three-dimensional processing and display coupled with 3-D manipulation capabilities by which users are able to pan and rotate the 3-D structure improve conspicuity of flaws. Providing such manipulation operations allow a clear depiction of the size and the location of various flaws in 3-D.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.10
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• pp.2102-2111
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• 1997

Hand written numeral is projected on the 3D space after pre-processing of inputs and it makes a index by tracking of numerals. It computes the distance between extracted every features. It is used by input part of recognition process from the statistical historgram of the normalization of data in order to adaptation from variation. One hundred unmeral patterns have used for making a standard feature map and 100 pattern for the recogintion experiment. The result of it, we have the recoginition rete is 93.5% based on thresholding is 0.20 and 97.5% based on 0.25.

• Journal of Korea Society of Industrial Information Systems
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• v.25 no.5
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• pp.41-48
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• 2020

Recently, as the demand for the mobile platform market in the virtual/augmented/mixed reality field is increasing, experiential content that gives users a real-world felt through a virtual environment is drawing attention. In this paper, as a method of tracking a tracker for user location estimation in a virtual space movement platform for motion capture of trainees, we present a method of estimating 3D coordinates of the 3D cross covariance through the coordinates of the markers projected on the image. In addition, the validity of the proposed algorithm is verified through rigid body tracking experiments.

• Korean Journal of Remote Sensing
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• v.34 no.6_1
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• pp.1009-1024
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• 2018

With the increased use of LiDAR (Light Detection and Ranging) that can obtain over millions of point dataset, methodologies for efficient search and dimensionality reduction for the point cloud became a crucial technique. The existing octree-based "parametric algorithm" has proved its efficiency and contributed as a part of PCL (Point Cloud Library). However, the implementation of the algorithm on GPU (Graphics Processing Unit) is considered very difficult because of structural constraints of the octree implemented in PCL. In this paper, we present a method for the parametric algorithm on GPU environment and implement a projection of the queried points on four directions with an improved noise reduction.

• Ecology and Resilient Infrastructure
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• v.8 no.2
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• pp.88-96
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• 2021

In surface image velocimetry, a wide area of a river is photographed at an angle to measure its velocity, inevitably causing image distortion. Although a distorted image can be corrected into an orthogonal image by using 2D projective coordinate transformation and considering reference points on the same plane as the water surface, this method is limited by the uncertainty of changes in the water level in the event of a flood. Therefore, in this study, we developed a tilt image correction technique that corrects distortions in oblique images without resetting the reference points while coping with changes in the water level using the geometric relationship between the coordinates of the reference points set at a high position the camera, and the vertical distance between the water surface and the camera. Furthermore, we developed a distortion correction method to verify the corrected image, wherein we conducted a full-scale river experiment to verify the reference point transformation equation and measure the surface velocity. Based on the verification results, the proposed tilt image correction method was found to be over 97% accurate, whereas the experiment result of the surface velocity differed by approximately 4% as compared to the results calculated using the proposed method, thereby indicating high accuracy. Application of the proposed method to an image-based fixed automatic discharge measurement system can improve the accuracy of discharge measurement in the event of a flood when the water level changes rapidly.

• Progress in Medical Physics
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• v.25 no.4
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• pp.233-241
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• 2014

The aim of this study is to develop a new software tool for 3D dose verification using $PRESAGE^{REU}$ Gel dosimeter. The tool included following functions: importing 3D doses from treatment planning systems (TPS), importing 3D optical density (OD), converting ODs to doses, 3D registration between two volumetric data by translational and rotational transformations, and evaluation with 3D gamma index. To acquire correlation between ODs and doses, CT images of a $PRESAGE^{REU}$ Gel with cylindrical shape was acquired, and a volumetric modulated arc therapy (VMAT) plan was designed to give radiation doses from 1 Gy to 6 Gy to six disk-shaped virtual targets along z-axis. After the VMAT plan was delivered to the targets, 3D OD data were reconstructed from 512 projection data from $Vista^{TM}$ optical CT scanner (Modus Medical Devices Inc, Canada) per every 2 hours after irradiation. A curve for converting ODs to doses was derived by comparing TPS dose profile to OD profile along z-axis, and the 3D OD data were converted to the absorbed doses using the curve. Supra-linearity was observed between doses and ODs, and the ODs were decayed about 60% per 24 hours depending on their magnitudes. Measured doses from the $PRESAGE^{REU}$ Gel were well agreed with the TPS doses at central region, but large under-doses were observed at peripheral region at the cylindrical geometry. Gamma passing rate for 3D doses was 70.36% under the gamma criteria of 3% of dose difference and 3 mm of distance to agreement. The low passing rate was resulted from the mismatching of the refractive index between the PRESAGE gel and oil bath in the optical CT scanner. In conclusion, the developed software was useful for 3D dose verification from PRESAGE gel dosimetry, but further improvement of the Gel dosimetry system were required.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.3
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• pp.434-442
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• 2018

In this paper, we propose a road lane color recognition method from the image obtained from a driving vehicle. In autonomous vehicle techniques, lane information becomes more important as the level of autonomous driving such as lane departure warning and dynamic lane keeping assistance is increased. In particular the lane color recognition, especially the white and the yellow lanes, is necessary technique because it is directly related to traffic accidents. In this paper, color information of lane and road area is mapped to a 2-dimensional S-color space based on lane detection. And the center of the feature distribution is obtained by using an improved mean-shift algorithm in the S-color space. The lane color is determined by using the distance between the center coordinates of the color features of the left and right lanes and the road area. In various illumination conditions, about 97% color recognition rate is achieved.

• Journal of the Korean Geotechnical Society
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• v.18 no.5
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• pp.251-260
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• 2002

Geotextile tribes are made of sewn geotextile sheet and hydraulically or mechanically filled with dredged materials. They have been applied in hydraulic and coastal engineering in recent years(shore protection structure, detached breakwater, groins, and jetty). Therefore, it is composed of geotextile and confined fill material. Recently, new preliminary design criteria supported by model and prototype tests, and some stability analysis calculations have been studied. The stability analysis of geotextile tube is composed of geotechnical and hydrodynamic analysis. The stability check points are sliding failure, overturning, bearing capacity failure against the wave attack. In this paper are presented the stability analysis method by empirical equation and 2-D equilibrium analysis for geotextile tube. Also, the hydraulic model tests were performed to verify the theoretical stability analysis with geotextile tube shape, filling ratio, significant wave height, and so on. The results of this study show that the stability of geotextile tube depends on the tube shape, contact area, projection area. The theoretical analysis and hydraulic model test show almost the same results.