• Imaging Science in Dentistry
• /
• 제47권2호
• /
• pp.117-122
• /
• 2017

Purpose: The aim of this study was to compare the use of 3-dimensional (3D) laser scanning and cone-beam computed tomography (CBCT) as methods of root surface measurement. Materials and Methods: Thirty teeth (15 maxillary first premolars and 15 mandibular first premolars) from 8 patients who required extractions for orthodontic treatment were selected. Before extraction, pre-treatment CBCT images of all the patients were recorded. First, a CBCT image was imported into simulation software (Mimics version 15.01; Materialise, Leuven, Belgium) and the root surface area of each tooth was calculated using 3-Matic (version 7.01, Materialise, Leuven, Belgium). After extraction, all the teeth were scanned and the root surface area of each extracted tooth was calculated. The root surface areas calculated using these 2 measurement methods were analyzed using the paired t-test (P<.05). Correlations between the 2 methods were determined by calculating the Pearson correlation coefficient. The intraclass correlation coefficient(ICC) was used to assess intraobserver reliability. Results: The root surface area measurements ($230.11{\pm}41.97mm^2$) obtained using CBCT were slightly greater than those ($229.31{\pm}42.46mm^2$) obtained using 3D laser scanning, but not significantly (P=.425). A high Pearson correlation coefficient was found between the CBCT and the 3D laser scanner measurements. The intraobserver ICC was 1.000 for 3D laser scanning and 0.990 for CBCT. Conclusion: This study presents a novel CBCT approach for measuring the root surface area; this technique can be used for estimating the root surface area of non-extracted teeth.

• 한국광학회지
• /
• 제27권5호
• /
• pp.165-173
• /
• 2016

본 연구는 2개의 라인 레이저를 이용하여 3차원 형상을 획득하는 방법에 대해 제안한다. 제안하는 방법은 532 nm와 630 nm 파장의 레이저를 이용하여 2-라인 레이저를 생성하고 이를 대상객체에 조사하여 반사되는 빛을 영상센서로 획득하는 것을 통해 3차원 점 데이터를 연산한다. 이를 위해 레이저와 카메라 간의 위치를 결정하고 각 레이저의 평면 방정식 계수를 추정하며 삼각법을 통해 이미지 공간의 라인을 3차원 공간의 점으로 변환한다. 제안하는 시스템은 2개의 라인 레이저와 데이터 정합을 위한 스태핑 모터 제어부와 영상을 획득하고 레이저의 라인을 추출하는 영상처리부, 그리고 추출된 라인으로부터 3차원 점 데이터를 처리하고 3D 모델을 생성하는 3D 모델링부로 나뉜다. 제안하는 방법은 기존 단일 레이저 스캐닝 방식과 비교하여 가려짐으로 인해 발생하는 데이터 소실문제를 해결할 수 있다.

• Spatial Information Research
• /
• 제15권1호
• /
• pp.53-65
• /
• 2007

지상라이다는 고정도의 3차원 영상을 제공하고 레이저빔을 현장이나 대상물에 발사하여 짧은 시간에 수백만점의 3차원좌표를 기록할 수 있는 최신 측량장비로서 다양한 응용분야에서 두각을 나타내고 있다 본 연구에서는 지상라이다를 이용한 아파트 건축물의 3차원 경계 추출을 다루었다. 실험측량결과 지상라이다로 아파트건축물의 3차원 경계를 신속하게 추출할 수 있었지만 지상기반시스템이므로 건축물 지붕 그리고 나무, 전주 때문에 건축물 저층부에서는 이것이 쉽지 않았다. 향후 토탈스테이션, 지상라이다, 항공라이다와 항공사진측량과의 결합을 통해 효율적인 3차원공간정보 획득이 가능할 것으로 기대된다.

• 한국산업융합학회 논문집
• /
• 제23권5호
• /
• pp.735-746
• /
• 2020

Recently, in Korea, various technology developments have been made to utilize 3D space and facility data such as unmanned aerial vehicles (UAV) and laser scanners with the goal of improving productivity at construction sites. However, the lack of related regulations for 3D laser scanner surveying has been a barrier to using the technology across the surveying industry. As a result, owners, contractors, and construction supervisors are reluctant to introduce and apply technology to the site. In this study, the guidelines (drafting and inspection work to be supervised by construction supervisors when constructing earthworks using laser scanners) was developed and presented so that the earth surveying and quantity calculation technology using a laser scanner could be applied and diffused in a construction site. Through the development of this guideline (proposal), it is judged that the supervision and inspection of earthworks quantity using a laser scanner will be activated in the field.

• 한국정밀공학회지
• /
• 제23권4호
• /
• pp.183-190
• /
• 2006

Digital 3D Real Object Duplication System (RODS) consists of 3D Scanner and Solid Freeform Fabrication System (SFFS). It is a device to make three-dimensional objects directly from the drawing or the scanning data. In this research, we developed an office type SFFS based on Three Dimensional Printing Process and an industrial SFFS using Dual Laser. An office type SFFS applied sliding mode control with sliding perturbation observer (SMCSPO) algorithm for control of this system. And we measured process variables about droplet diameter measurement and powder bed formation etc. through experiments. In case of industrial type SFFS, in order to develop more elaborate and speedy system for large objects than existing SLS process, this study applies a new Selective Dual-Laser Sintering (SDLS) process and 3-axis Dynamic Focusing Scanner for scanning large area instead of the existing f lens. In this process, the temperature has a great influence on sintering of the polymer. Also the laser parameters are considered like that laser beam power, scan speed, and scan spacing. Now, this study is in progress to evaluate the effect of experimental parameters on the sintering process.

• 한국측량학회지
• /
• 제26권6호
• /
• pp.561-569
• /
• 2008

현재, 3D 영상모형을 구축하기 위하여 위성영상, 항공영상 및 항공레이저 측량데이터가 주로 이용되고 있으나, 상기 데이터만을 이용하여 구축된 모형은 지형과 지물을 세밀하고 사실감 있게 표현하는데 제한적이기 때문에 고품질의 영상모형 구축이 필요한 실정이다. 3D 영상모형 구축시 3D 모형을 제작하고, 지상사진으로부터 텍스쳐를 제작하여 3D 모형에 사실감을 부여한다. 본 연구에서는 지형과 인공 시설물을 대상으로 사진측량 및 레이저측량 데이터를 이용하여 공간정확도, 세밀묘사 및 현실감이 강조된 실세계에 근접한 3D 영상모형을 구축하기 위한 기법을 분석하였다. 연구결과 위치정확도와 함께 사진과 같은 사실감을 확보한 3D 영상모형을 구축하였고 인터넷 3D 영상지도 서비스를 통하여 제공 할 수 있도록 하였다. 3D 영상모형을 이용하여 일조권분석, 경관분석, 시설물관리 등 다양한 분야에 활용할 수 있었다.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.123.1-123
• /
• 2001

For Autonomous navigation of the mobile robots, the robots' capability to recognize 3D environment is necessary. In this paper, an on-line 3D map building method for autonomous mobile robots is proposed. To get range data on the environment, we use an sensor system which is composed of a structured light and a CCD camera based on optimal triangulation. The structured laser is projected as a horizontal strip on the scene. The sensor system can rotate $\pm$ $30{\Circ}$ with a goniometer. Scanning the system, we get the laser strip image for the environments and update planes composing the environment by some image processing steps. From the laser strip on the captured image, we find a center point of each column, and make line segments through blobbing these center poings. Then, the planes of the environments are updated. These steps are done on-line in scanning phase. With the proposed method, we can efficiently get a 3D map about the structured environment.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.123.5-123
• /
• 2001

For autonomous navigation of the mobile robots, the robots' capability to recognize 3D environment is necessary. In this paper, an on-line 3D map building method for autonomous mobile robots is proposed. To get range data on the environment, we use a sensor system which is composed of a structured light and a CCD camera based on optimal triangulation. The structured laser is projected as a horizontal strip on the scene. The sensor system can rotate$\pm$30$^{\circ}$ with a goniometer. Scanning the system, we get the laser strip image for the environments and update planes composing the environment by some image processing steps. From the laser strip on the captured image, we find a center point of each column, and make line segments through blobbing these center points. Then, the planes of the environments are updated. These steps are done on-line in scanning phase. With the proposed method, we can efficiently get a 3D map about the structured environment.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
• /
• pp.153-155
• /
• 2003

Laser scanning has become a viable technique for the collection of a large amount of accurate 3D point data densely distributed on the scanned object surface. The inherent 3D nature of the sub-randomly distributed point cloud provides abundant spatial information. To explore valuable spatial information from laser scanned data becomes an active research topic, for instance extracting digital elevation model, building models, and vegetation volumes. The sub-randomly distributed point cloud should be segmented and classified before the extraction of spatial information. This paper investigates some exist segmentation methods, and then proposes an octree-based split-and-merge segmentation method to divide lidar data into clusters belonging to 3D planes. Therefore, the classification of lidar data can be performed based on the derived attributes of extracted 3D planes. The test results of both ground and airborne lidar data show the potential of applying this method to extract spatial features from lidar data.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2016년도 추계학술대회
• /
• pp.142-144
• /
• 2016

최근 제조 분야의 미래 유망기술이자, 막대한 파급효과를 유발할 것으로 예상되는 3D 프린터에 대한 관심이 급증하고 있으며, 3D 프린터 제품 가격의 하락에 따른 다양한 형태의 제품 보급이 확산되고 있다. 그러나 현재 보급되고 있는 개인용 3D 프린터는 기술적 성능의 한계점에 따라 높은 가공 정밀도를 요구하지 않는 단순한 형태의 사출물 출력에 사용되고 있으며 소비자 만족도가 매우 낮다. 따라서 본 논문에서는 기존 3D 프린터의 한계점을 극복하기 위해 정밀도가 높은 SLA 방식의 3D 프린터 사출방식과 사무용 레이저 프린터의 LSU(Laser Scanning Unit)를 융합한 폴리곤 미러 스캐닝 방식의 3D프린터를 제안하였다. 제안하는 3D프린터는 정밀도와 제조 속도를 개선하여 기존의 보급형 3D프린터를 대체할 수 있을 것으로 기대한다.