• 한국측량학회:학술대회논문집
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• 한국측량학회 2007년도 춘계학술발표회 논문집
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• pp.435-438
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• 2007

A laser scanning technique has been attracting much attention as a new technology to acquire location information. This technique might be applicable to a wide range of areas, most notably in geomatics, due to its high accuracy of location and automation of high-density data acquisition. In this study, the coastline was extracted using laser scanning. Through this laser scanning technique, efficient change detection of coast section can be ensured and also they can provide important information to be used when detecting a coast section in the future.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 지반공학 공동 학술발표회
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• pp.165-173
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• 2005

Generally, the instrumentation scheme for urban excavation projects consist of a series of tools such as inclinometer piezometer, loadcell, tiltmeter etc. Because almost every equipments are placed along several typical lines, it is impossible to evaluate the whole behavior of structures and adjacent buildings simultaneously. With laser scanning technique developed for surveying, all visible structures are scanned in the form of 3D digital data in a time schedule as planned. It can be analysed effectively the movements for all area affected by excavation even the spots in where no instrumentation tools. Although there are some parts to be refined such as scanning error, proper analysing software, it gives many advantages for realistic instrumentation works in the near future.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.768-772
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• 2008

Various scanning systems have been studied in many industrial areas to acquire a range data or to reconstruct an explicit 3D model. Currently optical technology has been used widely by virtue of noncontactness and high-accuracy. In this paper, we describe a 3D laser scanning system developped to reconstruct the 3D surface of a large-scale object such as a curved-plate of ship-hull. Our scanning system comprises of 4ch-parallel laser vision modules using a triangulation technique. For multi laser vision, calibration method based on least square technique is applied. In global scanning, an effective method without solving difficulty of matching problem among the scanning results of each camera is presented. Also minimal image processing algorithm and robot-based calibration technique are applied. A prototype had been implemented for testing.

• 비파괴검사학회지
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• 제27권3호
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• pp.246-254
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• 2007

The scanning laser source (SLS) technique is a promising new laser ultrasonic tool for the detection of small surface-breaking defects. The SLS approach is based on monitoring the changes in laser-generated ultrasound as a laser source is scanned over a defect. Changes in amplitude and frequency content are observed for ultrasound generated by the laser over uniform and defective areas. The SLS technique uses a point or a short line-focused high-power laser beam which is swept across the test specimen surface and passes over surface-breaking or subsurface flaws. The ultrasonic signal that arrives at the Rayleigh wave speed is monitored as the SLS is scanned. It is found that the amplitude and frequency of the measured ultrasonic signal have specific variations when the laser source approaches, passes over and moves behind the defect. In this paper, the setup for SLS experiments with full B-scan capability is described and SLS signatures from small surface-breaking and subsurface flaws are discussed using a point or short line focused laser source.

• 한국CDE학회논문집
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• 제16권2호
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• pp.126-136
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• 2011

The existing approaches to freeform building construction cause many problems. However, recent BIM technique development based on parametric modeling method and improvement of freeform materials manufacturing technology using IT technology encouraged many advanced countries to try experimental projects. Thus, laser scanning technique is in the limelight as a new alternative in the field of freeform building construction and inspection. This study selected a domestic small freeform building and practiced laser scanning and as-planned modeling by using Reverse Engineering. Then each deviation was comparatively analyzed through figures which extracted data by numerically analyzing the newly modeled as-built and Excel spread sheet. Through the process, limits and follow-up research subjects are discussed as well.

• 비파괴검사학회지
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• 제25권6호
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• pp.459-466
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• 2005

The scanning laser source (SLS) technique has been proposed recently as an effective way to investigate small surface-breaking defects, By monitoring the amplitude and frequency changes of the ultrasound generated as the SLS scans over a defect, the SLS technique has provided enhanced signal-to-noise performance compared to the traditional pitch-catch or pulse-echo ultrasonic methods, An extension of the SLS approach to map defects in microdevices is proposed by bringing both the generator and the receiver to the near-field scattering region of the defects, To facilitate near-field ultrasound measurement, silicon microcantilever probes are fabricated using microfabrication technique and their acoustical characteristics are investigated, Then, both the laser-generated ultrasonic source and the microcantilever probe are used to monitor near-field scattering by a surface-breaking defect.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.274-280
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• 2002

This paper addresses the vibration mode shape measurement technique utilizing a Continuous Scanning Laser Doppler Vibrometer (CSLDV). The continuous scanning capability is added to the conventional discrete Laser Doppler Vibrometer by reflecting the laser beams on the surface of the object using two oscillating mirrors. The bow scanning resulted from the proposed scanning method is eliminated by feedback control. The velocity output signal from the CSLDV is modulated to give the spatial velocity distribution in terms of coefficients which are obtained from the Fast Fourier Transformation of the time dependent velocity signal. Using the Chebyshev series form, the analysis of the vibration mode shape techniques for straight Bine scanning and 2 dimensional scanning are presented and discussed. The performance of the proposed SLDV is presented using the experimental results of the vibration mode shape of a plate

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.871-875
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• 2001

Laser photolithography technique is useful for fabricating micro-patterns of silicon wafers. In this work, the laser photolithography micromachining technique is optimized based on Taguchi method. Sensitivity analysis was performed using laser scanning speed and laser power level as the parameters. The results show that for the photoresist used in this work, a laser scan speed of $70{\mu}m/s$ at 50mW laser power gives the best result.

• 터널과지하공간
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• 제13권3호
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• pp.207-214
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• 2003

암반 사면에 대한 DEM(Digital Elevation Model)을 추출하기 위한 원거리 측정의 일반적인 방법은 laser scanner를 이용하는 방법과 수치사진측량 방법이 있다. 본 연구에서는 두 가지 기법을 적용하여 하나의 사면에 대해 DEM을 추출한 후, 각각의 기법을 통해 얻은DEM을 중첩시켜 그 차이를 분석함으로써 수치사진측량 기법의 적합성 및 개선점에 대해 살펴보았다. 이는 암반 사면의 절리 방향성을 측정하여 절리 구조를 파악하거나 사면형상 보존을 위한 DEM 추출하는데 적용할 수 있으며, 사면의 변화양상분석에 사용될 수 있다.

• 제어로봇시스템학회논문지
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• 제17권11호
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• pp.1159-1167
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• 2011

A novel 3D tube scanning technique is proposed. The proposed tube scanning technique is developed for a special tube inspection module which consists of four line-lasers and one camera. Using the scanning module, we can reconstruct the 360 degree shapes of the inner surfaces of a cylindrical tube. From an image frame captured by the camera, we reconstruct a partial tube model based on four laser triangulations. Then by aligning such partial models with respect to a reference tube axis, a complete 3D shape of the tube is reconstructed. The tube axis in each reconstructed frame is aligned with a 3D Euclidean transformation to the reference axis. Several experiments show that the proposed method can align multiple tube axes very accurately and reconstruct 3D shapes of a tube with very low shape distortion.