• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.867-872
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• 2020

Oil storage tanks are a major structure in chemical industrial complexes. Damage to the structure due to natural disasters or poor management can cause additional damage, such as leakage of chemicals, fire, and explosion, so it is essential to understand the deformation. In this study, data on oil storage tanks were acquired using a 3D laser scanner, and various analyzes were performed for storage tank management by comparing them with design data. Modeling of the oil storage tank was performed using the data and design drawings acquired by a 3D laser scanner. An inspection of the oil storage tank was effectively performed by overlapping. In addition, cross-sectional and exploded views of the deformation were produced to generate visible data on the deformation of the facility, and it was suggested that the oil storage tank had a maximum deformation of -7.16mm through quantitative analysis. Data that can be used for additional work was obtained by producing drawings to be precisely inspected for areas with large deformation. In the future, an inspection of oil storage tanks using 3D laser scanners is quantitative and visible data on oil storage tank deformation. This will greatly improve the efficiency of facility management by rebuilding it.

• The Journal of the Korea Contents Association
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• v.11 no.4
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• pp.428-439
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• 2011

It is well known that the sound characteristics of Korean bell depend on the shape and the alloy constituents. Development of the methods to acquire exact shape data and alloy constituents of the whole body of the bell is very important for the study and systematic management of Korean bells. The practical scanning and modeling methods to get shape data from optical triangulation laser scanners are proposed. The 3D shape data by the proposed methods can be the basis of diverse measurements such as curvature, volume, thickness and the distance between any two points. A nondestructive alloy constituents measuring method which can overcome the limitations of partial data collection and damages to Korean bells is also suggested to get the whole alloy characteristics. Following the developed methods, the data of the shapes and alloy constituents of 18 Korean bells are collected and the errors of existing measurement data for the shape have been corrected.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.10
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• pp.970-976
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• 2012

In this paper, a single LRF has been used to produce a 3D map for the mobile robot navigation. The 2D laser scanners are used for mobile robots navigation, where the laser scanner is applied to detect a certain level of area by the straight beam. Therefore it is limited to the usages of 2D obstacle detection and avoidance. In this research, it is designed to complement a mobile robot system to move up and down a single LRF along the yaw axis. During the up and down motion, the 2D data are stacked and manipulated to build a 3D map. Often a single LRF data are mixed with Gaussian and impulse noises. The impulse noises are removed out by the hybrid median filter designed in this research. The 2D data which are improved by deleting the impulse noises are layered to build the 3D map. Removing impulse noises while preserving the boundary is a main advantages of the hybrid median filter which has been used widely to improve the quality of images. The effectiveness of this hybrid median filter for rejecting the impulse noises has been verified through the real experiments. The performance of the hybrid median filter is evaluated in terms of PSNR (Peak Signal to Noise Ratio) and the processing time.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.1
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• pp.83-92
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• 2010

Emergence of high-resolution digital aerial cameras and airborne laser scanners have made innovative progress in photogrammetry and spatial information technology. The purpose of this study is to generate true orthoimage by recovering occlusion areas. The orthoimages were generated patch-based transformation. The occlusion areas were mutually corrected by using multiple aerial images. This study proposed a novel method of building roof based orthoimage generation and an effective method of occlusion area detection and recovery. The proposed methods could be efficient to generate true orthoimages in urban areas where occlusion areas are problematic.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.1
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• pp.47-56
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• 2010

The use of airborne LiDAR data obtained by airborne laser scanners has increased in the field of spatial information such as building modeling. LiDAR data consist of irregularly distributed 3D coordinates and lack visual and semantic information. Therefore, LiDAR data processing is complicate. This study suggested a method of LiDAR data segmentation using roof surface patches from aerial images. Each segmented patch was modeled by analyzing geometric characteristics of the LiDAR data. The optimal functions could be determined with segmented data that fits various shapes of the roof surfaces as flat and slanted planes, dome and arch types. However, satisfiable segmentation results were not obtained occasionally due to shadow and tonal variation on the images. Therefore, methods to remove unnecessary edges result in incorrect segmentation are required.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.8
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• pp.676-681
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• 2013

For underwater vehicles, the use of sensors such as cameras and laser scanners is limited by the difference in environment compared to robots designed to work on dry land. In underwater environments, if use is made of sound signals, valuable information can be obtained. The most important application is the localization of underwater sound sources. The estimated location of a sound source can be used to control underwater robots or submarines. Thus, the purpose of this research is to estimate the source's direction and location in a noisy underwater environment. The direction of the sound source is obtained using two hydrophones. Furthermore, if we assume that the robot or sound source is moving, the location of the sound source is estimated using more than two estimated directions. The feasibility of the developed algorithm is examined by experiments in a water tank and in the ocean.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.10
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• pp.803-810
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• 2009

Micromirrors have a wide range of applications such as optical switches, laser scanners, and digital projection displays. Due to their low performances and high costs, however, practical applications of micromirrors are quite limited. At present micromirrors demand not only a better design but also a simple fabrication process. In this study a twisting-type micromirror that can be driven by two thermal bimorph actuators bending in opposite directions is designed from electro-thermo-mechanical theories and fabricated through a simple MEMS process. Each actuator consists of $SiO_2$ and gold thin-film layers. Simplified analytical model has been built to optimize the performance of micromirror. Due to unexpected resistance increase of metal film and alignment mismatch during fabrication process, experimental rotation angles of micromirrors are about $11^{\circ}$ at applied voltages less than 0.6V. From numerical simulation and analytical studies, however, the next design can provide rotation angles over $20^{\circ}$ at the same applied voltage.

• Journal of Fashion Business
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• v.17 no.3
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• pp.74-84
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• 2013

The purpose of this research is to provide useable data for application in American and Korean apparel company. This data was developed by analyzing information of Korean and American body sizes obtained from "Size USA Project" and "Size Korea Project". The Subjects were 6,306 American females and 1,988 Korean females over 18 years old. 30 measurements and 14 computed values were chosen that were considered critical in making garments. And descriptive analysis, percentile analysis and t-test were used as statistical methods for analyzing measurements and computed value between the two countries. The results were as follows. It was determined that American women were larger and bigger than Korean women in all measurements and computed values, except for Shoulder Slope. Based on BMI values, we determined that American women had a distinct tendency towards being overweight. Through the comparison of drop values (i.e. the difference between Hip and Bust Girths or Hip and Waist Girths), ratio values (i.e. waist height divided by height) and Body Mass Index (BMI) between the two countries, we determined that American women's figures were shapelier than Korean women's. American women had higher hip heights and longer leg lengths for their height compared to Korean woman. Furthermore, the back shapes of Korean women were flatter than American women and BMI values indicated American women were relatively more overweight than Korean women.

• The Journal of Korea Robotics Society
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• v.7 no.2
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• pp.92-100
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• 2012

A map of complex environment can be generated using a robot carrying sensors. However, representation of environments directly using the integration of sensor data tells only spatial existence. In order to execute high-level applications, robots need semantic knowledge of the environments. This research investigates the design of a system for recognizing objects in 3D point clouds of urban environments. The proposed system is decomposed into five steps: sequential LIDAR scan, point classification, ground detection and elimination, segmentation, and object classification. This method could classify the various objects in urban environment, such as cars, trees, buildings, posts, etc. The simple methods minimizing time-consuming process are developed to guarantee real-time performance and to perform data classification on-the-fly as data is being acquired. To evaluate performance of the proposed methods, computation time and recognition rate are analyzed. Experimental results demonstrate that the proposed algorithm has efficiency in fast understanding the semantic knowledge of a dynamic urban environment.

• Broadcasting and Media Magazine
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• v.6 no.2
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• pp.84-101
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• 2001

In this paper, we present a primitive system design of a super multi-view(SMV) 3-D display system based on a focused light array(FLA) concept using reflective vibrating scanner array(ViSA). The parallel beam scanning using a vibrating scanner array is performed by moving left and right an array of curvature-compensated mirrors or diamond-ruled reflective grating attached to a vibrating membrane. The parallel laser beam scanner array can replace the polygon mirror scanner which has been used in the SMV 3-D display system based on the focused light array(FLA) concept proposed by Kajiki at TAO(Telecommunications) Advancement Organization). The proposed system has great advantages in the sense that it requires neither huge imaging optics nor mechanical scanning pals. Some mathematical analyses and fundamental limitations of the proposed system are presented. The proposed vibrating scanner array, after some modifications and refinements, may replace polygon mirror-based scanners in the near future.