• 대한치과기공학회지
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• 제42권2호
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• pp.65-71
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• 2020

Purpose: To know the transmittance of light when wearing shading goggles and to protect eyes from blue light emitted from dental scanner when using CAD/CAM works or inducing polymerization reactions of dental resin with curing unit and infrared light occurred when melting Dental precious metal and non-precious metal alloys. Methods: By measuring and comparing the average transmittances of blue light, visible light and infrared ight by using UV-Vis Spectrophotometer analysis measuring instrument, I compared 3 GREEN Color Goggles worn when casting Dental precious metal and non-precious metal alloys, and compared each of YELLOW, ORANGE Color Goggles worn when using Dental CAD/CAM scanners and Light Curing(LED) the Dental resin. Results: In blue light range, YELLOW Color Goggles are more effective than ORANGE Color Goggles. In infrared light range, No.12 Goggles are more effective than No.10 and No.11 Goggles. Conclusion: When wearing blue light shading goggles to avoid harmful blue light occurred in using dental scanner and curing light, and when wearing infrared light shading goggles to avoid harmful infrared light during casting, to avoid the Side Effects like transmittance rate of blue light and infrared light goggles becomes too high to block appropriate amount of harmful light or too low that causing lower image clarity.

• 치위생과학회지
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• 제15권2호
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• pp.226-231
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• 2015

본 연구는 세 가지 종류 스캐너에 따른 정확도를 비교 평가하기 위하여 시행되었다. 경석고 모형과 스캐너로 채득한 디지털 모형에 각 4지점씩 계측지점을 선정하였고, 이들 4지점사이를 DVC와 디지털 모형 측정 프로그램을 이용하여 길이를 측정하고, 다음과 같은 결론을 도출하였다. 세 가지 종류의 스캐너 가운데 레이저 스캐너가 백색광 스캐너나 청색광 스캐너보다 높은 정확도를 나타내었으나 이 세 가지 종류의 스캐너 모두가 임상적으로 사용하는 것이 가능하다.

• The Journal of Advanced Prosthodontics
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• 제6권6호
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• pp.468-473
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• 2014

PURPOSE. This study aimed to evaluate the accuracy of digitizing dental impressions of abutment teeth using a white light scanner and to compare the findings among teeth types. MATERIALS AND METHODS. To assess precision, impressions of the canine, premolar, and molar prepared to receive all-ceramic crowns were repeatedly scanned to obtain five sets of 3-D data (STL files). Point clouds were compared and error sizes were measured (n=10 per type). Next, to evaluate trueness, impressions of teeth were rotated by $10^{\circ}-20^{\circ}$ and scanned. The obtained data were compared with the first set of data for precision assessment, and the error sizes were measured (n=5 per type). The Kruskal-Wallis test was performed to evaluate precision and trueness among three teeth types, and post-hoc comparisons were performed using the Mann-Whitney U test with Bonferroni correction (${\alpha}=.05$). RESULTS. Precision discrepancies for the canine, premolar, and molar were $3.7{\mu}m$, $3.2{\mu}m$, and $7.3{\mu}m$, respectively, indicating the poorest precision for the molar (P<.001). Trueness discrepancies for teeth types were $6.2{\mu}m$, $11.2{\mu}m$, and $21.8{\mu}m$, respectively, indicating the poorest trueness for the molar (P=.007). CONCLUSION. In respect to accuracy the molar showed the largest discrepancies compared with the canine and premolar. Digitizing of dental impressions of abutment teeth using a white light scanner was assessed to be a highly accurate method and provided discrepancy values in a clinically acceptable range. Further study is needed to improve digitizing performance of white light scanning in axial wall.

• 한국콘텐츠학회논문지
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• 제12권10호
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• pp.357-364
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• 2012

치과용 스캐너를 기반으로 하는 디지털 모형은 기존의 전통적인 석고모형을 대체할 만큼 발전되고 있다. 본 연구의 목적은 디지털모형의 정확도와 신뢰도를 평가하고자 하였다. 상악의 전악모형을 주 모형으로 설정하여 주 모형으로부터 석고모형을 제작하였고(N=10), 치과용 백색광 스캐너를 이용하여 10개의 디지털모형 데이터를 채득하였다. 제작된 두 실험군(석고모형, 디지털모형)을 1명의 검사자가 2회에 걸쳐서 6곳의 계측지점을 측정하였다. 짝 표본 t-검정과 급내 상관계수을 이용하여 통계적인 분석을 하였다. 실험결과 측정값의 검사자 내 신뢰도는 급내 상관계수 결과 두 실험군 0.75에서 0.87의 범위를 보였다. 석고모형과 디지털 모형의 평균 오차값은 0.11mm에서 0.23mm의 범위를 나타내었고, 모든 계측지점에서 통계적으로 유의한 차이를 보였다(P<0.05). 본 실험결과 모든 계측지점에서 적정수준의 정확성은 확보되지 않았으나, 선행연구에 비추어 볼 때 임상적인 효용성은 검증되었다. 추가적으로 임상적인 사례를 통해 평가되어야 할 것으로 사료된다.

• 대한치과기공학회지
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• 제34권4호
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• pp.369-377
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• 2012

Purpose: The aim of study was to compare the dimensional stability of digitized dental stone replica using different color of gypsum materials using a white light scanner with three-dimensional software. Methods: A master model(500B-1, Nissin dental product, Japan) with the prepared lower full arch tooth was used. Several type IV stones(white, yellow, green) were used for 30 stone casts(10 casts each) duplicated a master model of mandible. The master model and the replicas were digitized with the non-contacting white light scanner to create 3-dimensional digital models. The linear distance between the reference points were measured and analyzed on the Delcam Copycad$^{(R)}$(Delcam plc, UK) 3D graphic software. One-way analysis of variance(ANOVA) combined with a Tukey multiple-range test were used to analysis the data(${\alpha}$=0.05). Results: There were considerable differences in mean values between gypsum materials within each color(white, yellow, green), and this difference was statistically significant, p=0.001. Conclusion: Digitization of dental materials on optical scanner was affected by color. Three different color of gypsum materials showed clinically acceptable accuracies of full arch digital model produced by them. Besides, these results will have to be confirmed in further clinical studies.

• 대한공간정보학회지
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• 제14권3호
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• pp.79-86
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• 2006

현재 3차원 지상 레이저 스캐너를 통해서 짧은 시간에 대상물의 수많은 위치에 대한 고정도의 3차원 좌표를 얻을 수 있다. 그래서 최근에 지상 레이저 스캐닝은 측지분야를 포함하여 토목공학, 고고학 및 건축, 그리고 응급서비스 및 국방, 기타 등 다양한 분야에서 널리 응용되고 있다. 본 연구는 지상 라이다를 이용한 현황측량을 다루었으며, 실험측량 결과 대상물의 선형 특징추출이 가능하였으며 토탈스테이션 측량성과에 필적하는 위치결정 정확도를 얻었다. 이를 통해 향후 항공 라이다와 항공사진측량기술과의 결합에 의해 지상 레이저 스캐닝의 잠재응용분야는 더욱 증대될 것으로 기대된다.

• Journal of the Optical Society of Korea
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• 제4권1호
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• pp.37-42
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• 2000

In this paper, we propose a super multi-view (SMV) 3-D display system using a vibrating scanner array (ViSA). The parallel beam scanning using a vibrating scanner array is performed by moving back and forth an array of curvature-compensated mirrors attached to two vibrating membranes. 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. The proposed system has great advantages in the sense that it requires neither huge imaging optics normechanical scanning parts. Some mathematical analyses and fundamental limitations of the proposed system are presented. The proposed vibrating scanner array, after some modifications and refinements, will replace polygon mirror-based scanners in the near future.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2004년도 Proceedings of 2004 Korea-Japan Joint Seminar on Particle Image Velocimetry
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• pp.1-13
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• 2004

A scanning stereo-PIV system was developed to measure the three-dimensional distribution of three-component velocity in a turbulent round jet. A laser light beam produced by a high repetition rate YLF pulse laser was expanded vertically by a cylindrical lens to form a laser light sheet. The light sheet is scanned in a direction normal to the sheet by a flat mirror mounted on an optical scanner, which is controlled by a programmable scanner controller. Two high-speed mega-pixel resolution C-MOS cameras captured the particle images illuminated by the light sheet, and stereoscopic PIV method was adopted to acquire the 3D-3C-velocity distribution of turbulent round jet in an octagonal tank filled with water. The jet Reynolds number was set at Re=1000 and the streamwise location of the measurement was fixed at approximately x = 40D. Time evolution of three-dimensional vortical structure, which is identified by vorticity, is visualized. It revealed that the existence of a group of hairpin-like vortex structures was quite evident around the rim of the shear layer of the jet. Turbulence statistics shows good agreement with the previous data, and divergence of a filtered (unfiltered) velocity vector field was $7\%\;(22\%)$ of root-me an-squared vorticity value.

• 자동차안전학회지
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• 제9권3호
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• pp.24-30
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• 2017

This paper presents the development of laser scanner based static obstacle detection algorithm for vehicle localization on lane lost section. On urban autonomous driving, vehicle localization is based on lane information, GPS and digital map is required to ensure. However, in actual urban roads, the lane data may not come in due to traffic jams, intersections, weather conditions, faint lanes and so on. For lane lost section, lane based localization is limited or impossible. The proposed algorithm is designed to determine the lane existence by using reliability of front vision data and can be utilized on lane lost section. For the localization, the laser scanner is used to distinguish the static object through estimation and fusion process based on the speed information on radar data. Then, the laser scanner data are clustered to determine if the object is a static obstacle such as a fence, pole, curb and traffic light. The road boundary is extracted and localization is performed to determine the location of the ego vehicle by comparing with digital map by detection algorithm. It is shown that the localization using the proposed algorithm can contribute effectively to safe autonomous driving.

• Journal of Korean Dental Science
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• 제17권1호
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• pp.1-13
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• 2024

With the advances of digital scanning technology in dentistry, the interests in facial scanning in orthodontics have increased. There are many different manufacturers of facial scanners marketing to the dental practice. How do you know which one will work best for you? What questions should you be asking? We suggest a clinical guideline which may help you make an informed decision when choosing facial scanners. The characteristics of 7 facial scanners were discussed in this article. Here are some considerations for choosing a facial scanner. *Accuracy: For facial scanners to be of real value, having an appropriate camera resolution is necessary to achieve more accurate facial image representation. For orthodontic application, the scanner must create an accurate representation of an entire face. *Ease of Use: Scanner-related issues that impact their ease of use include type of light; scan type; scan time; file type generated by the scanner; unit size and foot print; and acceptance of scans by third-party providers. *Cost: Most of the expenses associated with facial scanning involve the fixed cost of purchase and maintenance. Other expenses include technical support, warranty costs, transmission fees, and supply costs. This article suggests a clinical guideline to make the right choice for facial scanner in orthodontics.