• 전자공학회논문지
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• 제50권8호
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• pp.253-263
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• 2013

광학측정기법 중 주파수 스캐닝 간섭계는 기존 3차원 측정기법과 비교하여 광학 하드웨어 구조가 측정과정동안 고정되어 있어, 대물렌즈나 대상물체의 수직 스캐닝 없이 단지 광원의 주파수만 특정한 주파수 밴드내에서 스캐닝 하여 대상물체에 주사되므로, 우수한 광학 측정 성능을 보인다. 광원의 주파수를 변경하여 간섭계를 통해 간섭 영상을 획득한 후, 밝기 영상 데이터를 주파수 영역 데이터로 변환하고, 고속 푸리에 변환을 통한 주파수 분석을 이용하여 대상 물체의 높이 정보를 계측한다. 하지만, 대상물체의 광학적 특성에 기인한 광학노이즈와 주파수 스캐닝동안 획득되는 영상의 수에 따라 증가하는 영상처리시간은 여전히 주파수 스캐닝 간섭계의 문제이다. 이를 위해, 1) 편광기반 주파수 스캐닝 간섭계가 광학 노이즈에 대한 강인성을 확보하기 위해 제안되어진다. 시스템은 주파수 변조 레이저, 참조 거울 앞단의 ${\lambda}/4$ 판, 대상 물체 앞단의 ${\lambda}/4$ 판, 편광 광분배기, 이미지 센서 앞단의 편광기, 광섬유 광원 앞단의 편광기, 편광 광분배기와 광원의 편광기 사이에 위치하는 ${\lambda}/2$ 판으로 구성된다. 제안된 시스템을 이용하여, 편광을 기반으로한 간섭이미지의 대조대비를 조절할 수 있다. 2) 신호처리 고속화 방법이 간섭계 시스템을 위해 제안되며, 이는 그래픽 처리 유닛(GPU)과 같은 병렬처리 하드웨어와 계산 통합 기기 구조(CUDA)와 같은 프로그래밍 언어로 구현된다. 제안된 방법을 통해 신호처리 시간은 실시간 처리가 가능한 작업시간을 얻을 수 있었다. 최종적으로 다양한 실험을 통해 제안된 시스템을 정확도와 신호처리 시간의 관점으로 평가하였고, 실험결과를 통해 제안한 시스템이 광학측정기법의 실적용을 위해 효율적임을 보였다.

• Restorative Dentistry and Endodontics
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• 제22권1호
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• pp.447-463
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• 1997

The purpose of this study was to evaluate the effectiveness of copal varnish and five bonding agents(Scotchbond Multi-Purpose Plus Dental Adhesive System, Panavia 21, All Bond 2, Superbond D-Liner II plus, Fuji Duet) in reducing microleakage under amalgam restorations. Class V cavity were prepared on both buccal and lingual surface of sixty extracted human molars with cementum margin and were filled with different kinds of liners and amalgam. All teeth were stored at $37^{\circ}C$ in physiologic saline solution. After 1 week they were thermally stressed for 500 cycles between 5 and $55^{\circ}C$ in baths containing 0.5 % basic fuchsin dye. The dye penetrations were observed with a stereomicroscope. Scanning electron micrographs were taken of representative tooth sections from each group to assess the nature of the tooth/liner/amalgam interface. The statistical test were applied to the results using a one way analysis variance (ANOVA) and Duncan's multiple range test. The results were as follows ; 1. In all groups, the enamel margin showed significantly lower leakage value than the cementum margin (p<0.05). 2. At the dentin and enamel margins, the leakage value of Copalite-lined group showed significantly higher than that of no liner group (p<0.05), but showed significantly lower than that of bonding agent lined-groups (p<0.05). 3. There was no significant difference between the bonding agent lined-groups (p>0.05). 4. On the backscattered scanning electron microscopy observation, discontinuous gaps were observed between amalgam and dentin in the bonding agent-lined amalgam restorations and the bonding agents appeared to fill the gap space and were mixed with amalgam particles. At the amalgam/tooth interface, unsealed dentin and continuous gaps were found in both unlined and Copalite-lined restorations.

• 전자공학회논문지SC
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• 제43권6호
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• pp.16-26
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• 2006

본 논문에서는 평판형 디스플레이 장치의 필수 구성품인 투명한 ITO(Indium-Tin-Oxide) 유리를 가공하기 위한 펨토초(Femto-second) 레이저 미세 가공의 효율을 극대화하기 위해 가공 대상체의 정보를 추출하는 시스템을 제안한다. 제안한 시스템은 레이저 스캐닝 시스템을 활용하여 펨토초 레이저빔의 초점 거리 오차와 각도 오차를 사전에 계측하고 3차원으로 형상을 복원한다. 본 시스템은 라인 스캔 레이저, 고해상도 카메라, 리니어 모션 가이드(Linear Motion Guide), 시스템 제어부로 구성되어있다. 또한 본 시스템의 모델링을 통한 카메라와 레이저의 위치와 측정 결과와의 관계를 나타낼 수 있는 민감도 지수를 정의하고, 이를 활용하여 더욱더 정확한 측정이 가능한 시스템을 설계할 수 있었다. 가공 대상체인 ITO 유리의 높이와 표면 형상을 측정하고 3차원으로 형상을 복원하여 주사 탐침 현미경(SPM)으로 얻은 결과와 비교하여 본 시스템의 성능을 검증하였다.

• 한국임상수의학회지
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• 제11권2호
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• pp.529-537
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• 1994

Sector scanner which has a conical end is used to image through the intercostal space because heart is protected by the ribs. Cardiac data published all around the world were also obtained by sector scanner. Although scanners being used in every small animal practice and animal hospital at college in Korea include convex ape and linear type, linear type is not appropriate f3r cardiac scan because of a wide contact surface. The purpose of this study is to establish ultrasonographic images of normal cardiac structures by measuring shape, size of reflectable cardiac structure according to restraint position in scanning normal heart of the puppies with 6.5 MHz convex scanner(SonoAce 4500, Medison, Korea) used in our veterinary teaching hospital, Seoul national university. Seventeen male and female puppies considered having healthy hear by X-ray and clinical examination are used feom April to July 1994. Scanning point selection of probe head and the distinction of imaged cardiac structures were accomplished by necropsy and cardiac scanning performed through thoracotomy under general anesthesia. At 10 o'clock position of transducer(at an angle of 30$^{\circ}$ between imaginary line from elbow joint to 3rd sternum and probe head, 60$^{\circ}$ from body surface, 4th intercostal space of right thorax) with the marker of scanner toward the head of dogs right atrium, left atrium and left ventricle were observed in 2, 3, 4, 5 intercostal space(2cm from the sternum) of experimental dog positioned ventrodorsally under general anesthesia. Under these conditions, the numerical values of imaged diastolic hear are as follows : the distance from skin to apex(mean$\pm$S.D) 47.53$\pm$6.94mm, thickness of left ventricular wall 6.00$\pm$1.60mm, length of left ventricle 16.27$\pm$5.31mm, width of left ventricle 15,33$\pm$4.25mm, length of left atrium 12.33$\pm$3.82mm, width of left atrium 11. 33$\pm$3.94mm, length of right atrium 1.00$\pm$2.41mm, width of right atrium 11.21$\pm$2.76mm and the area of left ventricle 270.92$\pm$109.81mm$^2$, area of left atrium 98.00$\pm$41.08mm$^2$, area of right atrium 62.75$\pm$21.04mm$^2$.

• 지적과 국토정보
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• 제49권1호
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• pp.85-101
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• 2019

컴퓨터기술의 발달, 영상해석 기술의 고도화 및 경량 무인항공기(UAV)가 대중화되면서 'UAV와 각종 센서의 융합을 기반으로 한 응용시스템(UAS)'이 산업계 전반으로 확산되고 있다. 국가문화유산물의 기록, 유지 관리는 물론 파손 시 복구를 위해서는 효율적인 정밀 3차원 현상 모델링 재현과 주기적 육안점검 기술이 필요하다. 본 연구의 목적은 초대형 마애보살입상의 정밀 현상모델링 재현과 육안점검의 대안으로 UAS 영상을 기반으로 한 사진측량방법의 효용성을 검증하는 것이다. 이를 위해 고려시대(918-1392) 제작된 국내 최대 마애불이며 당초문양의 '보관(모자)'이 특징인 보물 제1324호, 시흥 소래산 마애보살입상을 대상으로 UAS 영상을 획득하고 검사점에 대한 UAS 영상해석과 토탈스테이션 측량시스템 간의 측위정확도를 비교하였다. 또한, 실세계좌표계 상의 3차원 현상모델링 및 선각 현상을 도화하여 문화재청의 정량적 규격 값과 비교하며 유지관리를 위한 육안점검 작업의 대체 가능성을 검토하였다. 특히, UAS 영상해석과 지상 레이저 스캐너에 의한 3차원 재현 모형간의 중첩해석을 통해 두 기법간의 활용성은 물론 2년 전 후의 상대적 변동 상태를 검토하였다. 연구결과, 대형 마애보살입상의 정밀 현상조사 및 육안점검의 대안으로 UAS 영상 해석법의 효용성을 확인할 수 있었으므로 향후, 대형 국가문화유산의 현상조사와 유지관리에 그 활용이 기대된다.

• 마이크로전자및패키징학회지
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• 제15권3호
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• pp.53-58
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• 2008

본 연구에서는 상용화된 2.4 GHz 영역대에서 사용되어지는 WiFi용 DPDT(Double Pole Double throw) switch 칩을 laser 비아 가공과 도금 공정을 이용하여 폴리머 기판내에 내장시켜 그 특성을 분석하였으며 통상적으로 실장되는 wire 본딩방식으로 패키징된 기판과 특성차이를 분석 비교하였다. 폴리머는 FR4기판과 아지노 모토사의 ABF(Ajinomoto build up film)를 이용하여 패턴도금법으로 회로를 형성하였다. ABF공정의 최적화를 위해 폴리머의 경화정토를 DSC (Differenntial Scanning Calorimetry) 및 SEM (Scanning Electron microscope)으로 분석하여 경화도에 따라 도금된 구리패턴과의 접착력을 평가하였다. ABF의 가경화도가 $80\sim90%$일 경우 구리층과 최적의 접착강도를 보였으며 진공 열압착공정을 통해 기공(void)없이 칩을 내장할 수 있었다. 내장된 기관과 와이어 본딩된 기판의 측정은 S 파라미터를 이용하여 삽입손실과 반사손실을 비교 분석하였으며 그 결과 삽입손실은 두 경우 유사하게 나타났지만 반사손실의 경우 칩이 내장된 경우 6 GHz 까지 -25 dB 이하로 안정적으로 나오는 것을 확인할 수 있었다.

• 대한치과보철학회지
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• 제45권3호
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• pp.303-309
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• 2007

Statement of problem. The effect of gold electroforming on gold alloy was not studied. Purpose. This in vitro study investigate the effect of gold electroforming on gold-silver-palladium alloy. Material and methods. Three pieces of gold strips had undergone the electroforming procedures on one side and then half of the side again electroformed. The set mode for this study was program 1 ($200{\mu}m$). And the processing time was 15min (1/20 time to form $200{\mu}m$ coping). The confocal laser scanning microscope (PASCAL 5, Carl Zeiss, Bernried, Germany) was used to measure the thickness of the pure gold layer electroformed on the gold strips. Half of the gold strip was coated two times with electroformed gold, and the other half one time. The data from the cone focal laser system was processed to get the vertical profile of the strips and the difference of the vertical height between the double coated and single coated layer was regarded as the thickness of the gold coating. The layer thickness value to built 3D image of the cone-focal laser was set $0.5{\mu}m$. Next to the measurement of the thickness of the coating, the Vicker's hardness test was done. It was performed on the double coated surface, single coated surface and non-coated surface (back side) three times each. Results. The mean thickness value gained from gold electroforming technique was measured to be $22{\mu}m$ for sample 1, $23{\mu}m$ for sample 2, $21{\mu}m$ for sample 3. In the same condition of time, power and the amount of electrolyte, the data showed no difference between samples. According to the results of variance analysis, the differences among the variations in number of coating were statistically insignificant (p>0.05), meaning that the two times of gold electroforming coating did not change the hardness of gold-silver-palladium alloy. Conclusion. The test of thickness of gold coating proved the coherency of the gold electroforming procedure, in other words, when the power, the exposed surface area, processing time and the amount of electrolytes were set same, the same thickness of gold would be coated on. The hardness test showed that the electroformed gold coating did not change the hardness of the gold-silver-palladium alloy when it is coated not more than $45{\mu}m$.

• Journal of the Optical Society of Korea
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• 제14권3호
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• pp.204-208
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• 2010

A scanning imaging spectrograph system was used in this study to retrieve readings of the 2-D distribution of $SO_2$ and BrO around the crater of the Sakurajima volcano in Japan. The measurement was carried out during the daytime on November 2, 2005. Measurements were made at the surface of the site, located 5 km from the Sakurajima crater. One hundred horizontal scans were performed. Each column scanned by the system consists of 64 vertical pixels in order to retrieve the spatial distributions of BrO and $SO_2$ in the plume in terms of slant column densities (SCDs). Measured spectra were analyzed to identify and quantify $SO_2$ and BrO in the volcanic plume utilizing the plume's specific absorption features in the ultra violet region. Two-dimensional BrO and $SO_2$ distributions in SCD were retrieved horizontally covering the upwind, crater and downwind areas, and vertically, including the plume in the center of the scanned image. Both horizontal and vertical dispersions of $SO_2$ SCD from the crater were successfully measured to be from $10^{17}$ to $4.5{\times}10^{18}$ molecules $cm^{-2}$. However, BrO was measured below $10^{15}$ molecules $cm^{-2}$, which is considered its background level.

• 사상체질의학회지
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• 제19권2호
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• pp.22-29
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• 2007

1. Objectives Sasang Contitutional Medicine, a part of the traditional Korean medical lore, treats illness through a constitutional typing system that categorizespeople into four constitutional types. A few of the important criteria for differentiating the constitutional types are external appearances, inner state of mind, and pathological patterns. We had been developing a 3D Automatic Face Recognition Apparatus (3D-AFRA) in order to evaluate the external appearances with more objectivity. This apparatus provides a 3D image and numerical data on facial configuration, and this study aims to evaluate the mechanical accuracy of the 3D-AFRA hardware. 2. Methods Several objects of different shapes (cube, cylinder, cone, pyramid) were each scanned 10 times using the 3D Automatic Face Recognition Apparatus (3D-AFRA). The results were then compared and analyzed with data retrieved through a laser scanner known for its high accuracy. The error rates were analyzed for each grid point of facial contour scanned with Rapidform2006 (Rapidform2006 is a 3D scanning software that collects grid point data for contours of various products and products and product parts through 3D scanners and other 3D measuring devices; the grid point data thusly acquired is then used to reconstruct highly precise polygon and curvature models). 3. Results and Conclusions The average error rate was 0.22mm for the cube, 0.22mm for the cylinder, 0.125mm for the cone, and 0.172mm for the pyramid. The visual data comparing error rates for measurement figures retrieved with Rapidform2006 is shown in $Fig.3{\sim}Fig.6$. Blue tendency indicates smaller error rates, while red indicates greater error rates The protruding corners of the cube display red, indicating greater error rates. The cylinder shows greater error rates on the edges. The pyramid displays greater error rates on the base surface and around the vertex. The cone also shows greater error around the protruding edge.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1214-1218
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• 2005

As demands for precision parts are increased, existing methods to fabricate them such as MEMS, LIGA technology have the technical limitations like high precision, high functionality and ultra miniaturization. A micro-stereolithography technology based on $DMD^{TM}$(Digital Micromirror Device) can meet these demands. In this technology, STL file is the standard format as the same of conventional rapid prototyping system, and 3D part is fabricated by stacking layers that are sliced as 2D section from STL file. Whereas in conventional method, the resin surface is cured as scanning laser beam spot according to the section shape, but in this research, we use integral process which enables to cure the resin surface at one time. In this paper, we deal with the dynamic pattern generation and $DMD^{TM}$ operation to fabricate micro structures. Firstly, we address effective slicing method of STL file, conversion to bitmap, and dynamic pattern generation. Secondly, we suggest $DMD^{TM}$ operation and optimal support manufacturing for $DMD^{TM}$ mounting. Thirdly, we examine the problems on continuous stacking layers, and their improvements in software aspects.