• 한국측량학회:학술대회논문집
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• 한국측량학회 2005년도 추계학술대회
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• pp.81-104
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• 2005

가상공간 시현이나 GIS 및 이동통신과 같은 다양한 응용분야에 정확한 3차원 도시모델은 기본적인 자료가 되고 있다. LiDAR 시스템은 대상물의 3차원 정보를 직접적으로 획득할 수 있는 새로운 시스템이다. LiDAR 자료로부터 수동적으로 3차원 정보를 구축하는 것은 많은 시간과 비용을 필요로 한다. 이와 같은 이유로 많은 연구가 자동화에 그 초점을 맞추고 있다. 본 연구에서는 필터링기법을 이용해서 LiDAR 자료로부터 지면과 비지면을 분류하고, 지면점을 이용하여 DTM을 생성하고, 비지면점을 이용해서 건물을 구축하였다. 정확도의 평가결과 DTM은 고층아파트지역에서 약 0.16m, 저층주거지역에서 0.59m의 오류가 나타났으며, 건물의 경우 1/5,000 수치지형도의 정밀도와 부합하는 결과를 나타냈다.

• 도시과학
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• 제7권2호
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• pp.53-60
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• 2018

Digital Twin is a technology that creates a photocopy of real-world objects on a computer and analyzes the past and present operational status by fusing the structure, context, and operation of various physical systems with property information, and predicts the future society's countermeasures. In particular, 3D rendering technology (UAS, LiDAR, GNSS, etc.) is a core technology in digital twin. so, the research and application are actively performed in the industry in recent years. However, UAS (Unmanned Aerial System) and LiDAR (Light Detection And Ranging) have to be solved by compensating blind spot which is not reconstructed according to the object shape. In addition, the terrestrial LiDAR can acquire the point cloud of the object more precisely and quickly at a short distance, but a blind spot is generated at the upper part of the object, thereby imposing restrictions on the forward digital twin modeling. The UAS is capable of modeling a specific range of objects with high accuracy by using high resolution images at low altitudes, and has the advantage of generating a high density point group based on SfM (Structure-from-Motion) image analysis technology. However, It is relatively far from the target LiDAR than the terrestrial LiDAR, and it takes time to analyze the image. In particular, it is necessary to reduce the accuracy of the side part and compensate the blind spot. By re-optimizing it after fusion with UAS and Terrestrial LiDAR, the residual error of each modeling method was compensated and the mutual correction result was obtained. The accuracy of fusion-based 3D model is less than 1cm and it is expected to be useful for digital twin construction.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 춘계학술대회 논문집
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• pp.187-194
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• 2008

LiDAR는 일반 항공사진 및 위성영상과는 달리 사물의 높이를 측정할 수 있어 산림의 3차원 모델링을 수행할 수 있다. 본 연구에서는 이러한 LiDAR의 특성을 이용하여 산불이 발생한 강원도 양양지역 산림의 물리적 피해를 분석하였으며, 디지털 항공사진으로부터 Normalized Difference Vegetation Index (NDVI)를 추출하여 산림의 생물학적 피해를 분석하였다. 산림의 물리적 피해는 임관의 피해정도에 따라 지표면에서 반사되는 Point Data의 개수의 비율로서 추정을 하였다. 피해정도의 고저(高低)를 구분하는 기준은 통계적 방법 (Jenk's Natural Break) 으로부터 추정된 0.3594을 사용하였으며, 지표면 반사비율이 0.3594 이상인 경우 물리적 피해정도를 고(高, Serious Physical Damage; SPD), 지표면 반사비율이 0.3594 이하인 경우 물리적 피해정도를 저(低, Light Physical Damage; LPD)로 나타내었다. 또한 생물학적 피해는 일반적인 NDVI 값의 범위(-1

• Ocean and Polar Research
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• 제32권1호
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• pp.73-84
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• 2010

A terrestrial LiDAR was used to acquire precise and high-resolution topographical information of Malipo beach, Korea. Terrestrial LiDAR and RTK-DGPS (VRS) were mounted on top of a survey vehicle and used to scan 20 times stop-and-go method with 250 m spacing intervals at ebb tides. In total, 7 measurements were made periodically from 2008 to 2009 and after each beach replenishment event. We carried out GIS-based 3D spatial analysis such as slope and volume calculations in order to assess topographical changes over time. In relation to beach replenishment, comparative analysis of each volume change revealed them to be similar. This result indicates that the terrestrial LiDAR measurements are accurate and can be used to analyze temporal topographical changes. In conclusion, the methodology employed in this study can be used efficiently to exercise coastal management through monitoring and analyzing beach process such as erosion and deposition.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2004년도 춘계학술발표회논문집
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• pp.449-454
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• 2004

Nowadays, flood hazard maps have been generated to minimize the loss of human lives due to flooding domestically. To generate the flood hazard maps, LiDAR data have mainly been used to provide topographic data. The LiDAR data requires, however, relatively higher cost and processing time. Therefore, the needs of validating possible use of topographic maps as an alternative source of LiDAR, which have been already existed from the NGIS project over the nation, has been raised. In this background, this study has generated a DEM over City of Kuri as a pilot study using conventional 1:1,000 and 1:5,000 topographic maps emphasizing the linkage of river profile with breakline processing algorithm to build the essential topographic data as accurate as possible. The results showed that the RMSE from topographic maps and LiDAR were 3.49 and 2.282 meter, respectively. Further study needs to be made to decide possible use of topographic maps instead of LiDAR including more easier updating of topographic maps to support flood map generation. In addition, 1:1,000 topographic mapping, which is limited to the urban areas so far, needs to be extended to the river areas.

• 한국지리정보학회지
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• 제20권1호
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• pp.152-161
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• 2017

모바일 매핑 시스템(Mobile Mapping System: MMS) 센서를 이용한 3차원 정밀지도의 구축은 자율주행 자동차 개발에 필요한 기술이다. 본 논문은 MMS LiDAR(Light Detection And Ranging) 센서를 이용하여 획득한 점군자료를 이용하여 도로주변의 3차원 객체 추출에 관한 연구를 수행하였다. 우선, MMS LiDAR 점군자료 이용하여 수치표면모형(DSM: Digital Surface Model)을 제작하고, 생성된 DSM을 기반으로 경사도 지도를 제작하였다. 추출된 경사도 정보를 이용하여 도로주변의 3차원 객체를 식별하였고, 모폴로지 필터링 기법을 이용하여 도로주변의 3차원 객체 중 총 97%의 객체를 추출하였다. 본 연구는 MMS 센서를 이용하여 획득한 공간정보자료를 기반으로 도로 주변의 3차원 객체를 추출함으로써 최근 주목받고 있는 자율주행기술의 활용성에 관한 방안을 제시하였다는데 의의가 있다.

• 한국지반환경공학회 논문집
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• 제11권3호
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• pp.63-68
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• 2010

본 연구에서는 지상 LiDAR(Light Detection And Ranging) 스캔자료를 이용하여 토석류 재해 발생지역에 대한 토석류 발생량을 산정하고자 하였다. 충북 제천시를 연구대상지역으로 선정하여, 1:5000 수치지도를 이용한 DEM(수치표고모형)자료와 LiDAR 측량자료를 이용한 수치표고모형자료를 비교분석 하고 토석류 발생량을 산정하였다. 연구결과 침식량은 $24,150m^3$, 퇴적량은 $14,296m^3$로 산정되었고, 수로형 토석류와 사면형 토석류의 형태, 만곡부에서의 퇴적 등이 적절히 표현되었다. 토석류 발생량의 산정연구는 토석류 재해저감이나 대책수립 및 수치모의에 유용한 기초자료로 활용 될 것이다.

• 한국산업융합학회 논문집
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• 제25권6_3호
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• pp.1147-1154
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• 2022

Now that the development of autonomous driving is progressing, LiDAR has become an indispensable element. However, LiDAR is a device that uses lasers, and laser side effects may occur. One of them is the much-talked-about eye-safety, and developers have been satisfying this through laser characteristics and operation methods. But eye-safety is just one of the problems lasers pose. For example, irradiating a laser with a specific energy level or higher in a dusty environment can cause deterioration of the dust particles, leading to a sudden explosion. For this reason, the dust ignition proof regulations clearly state that "a source with a pulse period of less than 5 seconds is considered a continuous light source, and the average energy does not exceed 5 mJ/mm 2 or 35 mW" [2]. Energy of output optical power is limited by the law. In this way, the manufacturer cannot define the usage environment of the LiDAR, and the development of a LiDAR that can be used in such an environment can increase the ripple effect in terms of use in application fields using the LiDAR. In this paper, we develop a LiDAR with low optical power that can be used in environments where high power lasers can cause problems, evaluate its performance. Also, we discuss and present one of the directions for the development of LiDAR with laser power limited by dust ignition proof regulations.

• 한국환경과학회지
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• 제31권6호
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• pp.479-490
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• 2022

This study was to evaluate the utilization of terrestrial light detection and ranging for forest inventory in coniferous forests. Heights and diameter of the stand trees were measured manually using the traditional measurement method and the method using terrestrial LiDAR. The results of two methods were compared and analyzed to evaluate accuracy and feasibility. The terrestrial LiDAR used fixed and handy types to compare the accuracy between different operational methods. Comparative analyses used a paired t-test and Bland-Altman plot analysis. In the case of tree heights, the average of difference between the traditional method and terrestrial LiDAR for each plot was 0.81 m, -0.07 m, and 0.13 m for fixed type; 2.88 m, 1.19 m, and 0.93 m for the handy type. In the case of tree diameter at breast height, the average value of the difference between traditional methods and terrestrial LiDAR for each plot was 0.13 cm, -0.66 cm, and -0.03 cm for fixed type; 2.36 cm, 2.13 cm, and 1.92 cm for the handy type. The values from the method using the fixed type was highly consistent with that using the traditional measurement methods; the average difference was closer to zero. The crown density influences the precision of the height measurement using terrestrial LiDAR in coniferous forests. Therefore, future studies should focus on verifying the accuracy of terrestrial LiDAR in forests and on expanding the utilization of terrestrial LiDARs according to their operational methods.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.933-938
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• 2014

The combined method utilizing airborne LiDAR and GIS data is suggested to extract 3-dimensional hybrid city model including roads and buildings. Combining the two types of data is more efficient to estimate the elevations of various types of roads and buildings than using either LiDAR or GIS data only. This method is particularly useful to model the overlapped roads around the so called spaghetti junction. The preliminary model is constructed from the LiDAR data, which can give wrong information around the overlapped parts. And then, the erratic vertex points are detected by imposing maximum vertical grade allowable on the elevated roads. For the purpose of efficiency, the erratic vertex points are corrected through linear interpolation method. To avoid the erratic treatment of the LiDAR data on the facades of buildings 2 meter inner-buffer zone is proposed to efficiently estimate the height of a building. It is validated by the mean value (=5.1%) of differences between estimated elevations on 2 m inner buffer zone and randomly observed building elevations.