• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.6
• /
• pp.1955-1960
• /
• 2010

A performance of CNC 3-axis pipe profile-cutting machine we developed was evaluated by measuring and verifying a positioning accuracy of its feeding unit and a cutting shape accuracy of pipe workpiece. The positioning accuracy was verified by comparing moving distance actuated by PLC motion controller with actual one measured by a laser interferometer. The cutting shape accuracy was also verified by comparing a cutting shape obtained through scanning and 3D modeling the pipe workpiece with that through CL data.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.51 no.3
• /
• pp.155-160
• /
• 2002

This paper focuses on the problem of local obstacle avoidance of mobile robots. To solve this problem, the safety direction section search algorithm is suggested. This concept is mainly composed with non-collision section and collision section from the detecting area of laser scanning sensor. Then, we will search for the most suitable direction in these sections. The proposed local motion planning method is simple and requires less computation than others. An environment model is developed using the vector space concept to determine robot motion direction taking the target direction, obstacle configuration, and robot trajectory into account. Since the motion command is obtained considering motion dynamics, it results in smooth and fast as well as safe movement. Using the mobile base, the proposed obstacle avoidance method is tested, especially in the environment with pillar, wall and some doors. Also, the proposed autonomous motion planning and control algorithm are tested extensively. The experimental results show the proposed method yields safe and stable robot motion through the motion speed is not so fast.

• Journal of Korean Society of Water and Wastewater
• /
• v.31 no.6
• /
• pp.619-628
• /
• 2017

As the 3D laser scanning technology capable of databaseing large sewage box culverts becomes possible, it is necessary to develop a standardization manual that can clearly distinguish the structural and operational defect types of box culver and analyze the defect data. In this study, we collected and analyzed defects in sewage box culverts of 14,827m in total by selecting three districts in Korea. The major defects were surface damages, and their defect densities were $2.17m^2/m$, $0.27m^2/m$ and $0.10m^2/m$ for aggregate exposure, Steel reinforcement exposure, and Steel reinforcement projecting. In order to support the decision of the box culverment management, it was divided into five grades and each defect code and defect score were allocated. The results of this study are useful for the diagnosis of the sewage box culverts in Korea and it is expected to support a decision making for management.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.38 no.2
• /
• pp.27-32
• /
• 2001

In this paper, the three dimension scanner system employing the parallel camera model is discussed. The camera calibration process and the three dimension scanning algorithm are developed. The laser strip line is utilized for assisting stereo matching. An object being scanned rotates on the plate which is activated by a stepping motor, The world coordinate which is. the measured distance from the camera to the object is converted into the model coordinate. The facets created from the point. cloud of the model coordinate is used for rendering the scanned model by using the graphic library such as OpenGL. The unmatched points having no validate matching points are interpolated from the validate matching points of the vicinity epipolar lines.

• 한국공간정보시스템학회:학술대회논문집
• /
• 2002.03a
• /
• pp.59-64
• /
• 2002

컴퓨터 그래픽스 기술과 H/W의 발달로 3D GIS에 대한 연구가 활발히 진행되고 있다. 최근 3D GIS에 대한 활발한 연구 중 3D 가상도시의 구축이 중요한 연구로 떠오르고 있다. 3D 가상도시는 국방, 교통, 통신, 지적, 지하시설물, 관광, 도시계획, 도시모델링 등에 다양하게 활용될 수 있다. 현재 우리나라에서 3D 가상도시의 구축은 미약하지만 앞으로 그 수요는 더욱 더 많아질 것이다. 3D 가상도시의 구축에는 GIS, 컴퓨터 그래픽스, Database, 자료구조, 3D 모델링 등의 다양한 기술이 필요하다. 3D 가상도시의 구축의 방법은 크게 1/1,000수치지도+실제측량, 1/1,000수치지도+입체 인공위성 영상+수치사진측량, 1/1,000수치지도+항공사진측량 도화원도, 1/1,000수치지도+항공레이저스캐닝의 방법을 적용해 볼 수 있다. 현재 우리나라 여건상 첫 번째 방법이 가장 일반적으로 사용이 되나 도화원도에 대한 규제를 완화하여 세 번째 방법을 적용하는 것이 가장 효과적일 것이다. 3D 가상도시는 인터넷 기술과 접목이 되어 3D Web GIS의 형태로 앞으로의 GIS 주류를 이룰 것이다. 그러나 국내에서 3D 가상도시의 구축에 관한 연구는 미약한 수준이다. 3D 자료취득, 자료처리, 모델링 부문에 대한 연구가 시급하다.

• Proceedings of the KIEE Conference
• /
• 2000.07c
• /
• pp.2266-2268
• /
• 2000

본 논문에서는 스캐닝 미러의 일종으로, 광저장 장치의 픽업헤드용으로 미세회전을 하면서 레이저 빔을 편향시키는 용도로 사용되는 미러를 제작하고 구동실험을 하였다. 제작된 미러의 크기는 $2400{\times}2400{\times}64{\mu}m^3$이고, 빔 스프링은 $500{\times}9.6{\times}64{\mu}m^3$이다. 니켈 전해 도금으로 29${\mu}m$ 높이의 구동 전극을 제작하였고(세가지 모델: 공기통로가 없는 전극, 공기통로와 간격이 각각 200${\mu}m$인 전극, 공기통로와 간격이 각각 100${\mu}m$인 전극), 미러판과 전극을 조립하여(미러판과 전극 사이의 간격은 각각 29${\mu}m$, 26${\mu}m$, 26${\mu}m$) 구동실험을 하였다. 공진 주파수의 계산간은 576Hz, 측정값은 3개의 미러에서 모두 568Hz이었다. 전극과 미러판의 간격이 최대 접근거리 18${\mu}m$가 되도록 미세 회전을 시켰을 때, 공기통로가 없는 전극에서는 공진 주파수가 524Hz, 공기통로가 200${\mu}m$인 전극에서는 544Hz로 각각 감쇠되었고, 공기통로가 100${\mu}m$인 전극에서는 그대로 568Hz이었다.

• Korean Journal of Optics and Photonics
• /
• v.20 no.6
• /
• pp.328-333
• /
• 2009

We proposed a three-dimensional holographic display technique without twin image noise by converting a complex hologram to an off-axis hologram. To implement the proposed technique we record the complex hologram of a three dimensional object that is composed of two slides located with different depth locations. We added spatial carrier to the complex hologram and after that, extract the real part of the spatial-carrier-added hologram. This converts the complex hologram to an off-axis hologram. We also reconstruct the off-axis hologram using a spatial light modulator for three dimensional display.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.20 no.2
• /
• pp.137-143
• /
• 2002

In this study we generated digital orthophoto from LIDAR data. To generate digital orthophoto, we make TIN from raw laser scanning data(XYZ point data) and compiled DSM from this TIN. In this procedure much noise appeared along the break lines in DSM and this can give bad effect to the quality of digital orthophoto. Therefore, we applied various techniques which can refine the break line. In the result, we concluded that the fusion of LIDAR DEM of lowland and extracted buildings was adequate to generating DSM. So we generated the digital orthophoto from DSM generated from this technique. In the result of quality test, the positional accuracy of this digital orthophoto was better than the positional accuracy of 1:5,000 map.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.20 no.6
• /
• pp.114-120
• /
• 2021

This study is focused on the root mean square and peak-to-valley based on the injection conditions of the f-theta lens, one of the main components of laser printers and laser scanning systems. The f-theta lens of an aspherical plastic lens requires ultra-preaction. Injection molding is typically used for the mass production of aspherical plastic lenses. In the injection-molding method, the resin in the lens shape is filled with the resin after melting the plastic pellets at a constant temperature and then cooled. It is necessary to maintain a uniform injection molding system to produce high-quality lenses. These injection-molding systems are influenced by different factors, such as pressure, speed, temperature, mold, and cooling. It is possible to obtain a lens that exhibits the optical characteristics required to achieve harmony. We investigated the root mean square and peak-to-valley caused by variations in temperature, a critical parameter in the melting and cooling of plastic resins generated inside and outside the injection mold.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.20 no.9
• /
• pp.20-27
• /
• 2021

The effective surface of lens was studied for injection molding process and to enable mass production of f-theta lens, which is the primary component of laser printers and laser scanning systems. Injection molding is an optimal method if f-theta lens is frequently used for the mass production of plastic lenses as an aspherical lens that requires ultra-precision. A uniform injection molding system should be maintained to produce high quality lenses. Additionally, to maintain these injection molding systems, various factors such as pressure, speed, temperature, mold and cooling should be considered. However, a lens with the optical characteristics of an f-theta lens can be obtained. The effects of melting and cooling of plastic resin on the effective surface of f-theta lenses and the numerous factors that affect the injection molding process were studied.