• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.219-222
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• 2008

3차원 인체 스캐너로부터 얻어진 인체형상데이터는 여러 인체에 대한 3차원 평균 모델을 만들어 내는 등의 통계적 분석이나 자세 변경을 위해 필요한 내부 골격 구조와 골격과 피부조직 사이의 관계 등을 계산해 내기 어렵다. 또, 이러한 통계적 분석을 위해서는 각 모델 간의 상응 관계가 확립되어야 하지만 스캐너로부터 얻어진 인체 형상 데이터들은 측정 환경이나 대상에 따라 각각이 서로 상이한 기하학적 구조로 이루어져 있다. 본 논문에서는 템플릿 모델을 3차원 인체데이터에 맞도록 변형함으로써 다수의 인체 형상에 대하여 토폴로지를 일치시키도록 한다. 3차원 인체 데이터에 대해 템플릿 모델이 가장 근사한 형상이 되도록 하는 변형을 자동으로 찾아내기 위해서 표면 위에 정의된 특징점들을 사용한다. 또한, 기존에 찾아둔 특징점군 및 변형정보 데이터가 충분히 많다면 새로운 변형을 계산하는 데 유용하게 사용될 수 있음을 보인다. 이렇게 상응 관계가 확립된 모델들은 삼차원 벡터 공간의 점들의 집합으로 표현 및 통계적 분석이 가능하게 된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.16-22
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• 2019

Off-line programming and robot calibration through simulation are essential when setting up a robot in a robot automation production line. In this study, we developed a new robot calibration method to match the CAD data of the production line with the measurement data on the site using 3D scanner. The proposed method calibrates the robot using 3D point cloud data through Iterative Closest Point algorithm. Registration is performed in three steps. First, vertices connected by three planes are extracted from CAD data as feature points for registration. Three planes are reconstructed from the scan point data located around the extracted feature points to generate corresponding feature points. Finally, the transformation matrix is calculated by minimizing the distance between the feature points extracted through the ICP algorithm. As a result of applying the software to the automobile welding robot installation, the proposed method can calibrate the required accuracy to within 1.5mm and effectively shorten the set-up time, which took 5 hours per robot unit, to within 40 minutes. By using the developed system, it is possible to shorten the OLP working time of the car body assembly line, shorten the precision teaching time of the robot, improve the quality of the produced product and minimize the defect rate.

• Fashion & Textile Research Journal
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• v.16 no.6
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• pp.935-944
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• 2014

This study was about to investigate the characteristics of elementary school students' feet growth, comparing and analyzed the measured values and the index values of 3D scan data. As the results from analyzing the measured values, the all measurement items excluding 'Toe 5 angle' showed some significant differences among the age classes, knowing that the elementary school students' feet were continually grown. Although, the items of length, thickness, width, height and circumference indicate some rapid growth of feet at 11 years old, but it appears slowing growth of 'Foot width' after the age of 11 years old. The angle item didn't show any sequential differences according to ages. As the results from analyzing the index values, the children in higher grades have longer 'Toe 5', thicker ankles, wider and thicker the superior part of feet than the children in lower grades. For the superior and the middle part of feet were lowly raised, their Arch height was low and thick. The inferior part of feet showed narrow width and higher height. Giving that the Medial ball width was wide and the Toe 1 angle is high for the children in higher grades, it is expected that the Metatarsophalangeal I might be more projected than that of children in lower grades. Likewise, knowing that the male students' feet shape was bigger than female students' feet from the result that the male students' index values were higher.

• The Korean Journal of Nuclear Medicine
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• v.30 no.4
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• pp.548-559
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• 1996

A series of performance measurements of positron emission tomography (PET) were performed following the recommendations of the Computer and Instrumentation Council of the Society of Nuclear Medicine and the National Electrical Manufacturers Association. We investigated the performance of the General Electric $Advance^{TM}$ PET. The measurements include the basic intrinsic tests of spatial resolution, scatter fraction, sensitivity, and count rate losses and randoms. They also include the tests of the accuracy of corrections: count rate linearity correction, uniformity correction, scatter correction and attenuation correction. GE $Advance^{TM}$ PET has bismuth germanate oxide crystals (4.0mm transaxial ${\times}$ 8.1mm axial ${\times}$ 30.0mm radial) in 18 rings, which form 35 imaging planes spaced by 4.25mm. The system has retractable tungsten septa 1mm thick and 12cm long. Transaxial resolution was 4.92mm FWHM in 2D and 5.14mm FWHM in 3D at the center. Average axial resolution in 2D decreased from 3.91mm FWHM at the center to 6.49mm FWHM at R=20cm. Average scatter fraction of direct and cross slices was 9.57%. Dead-time losses of 50% corresponded to a radioactivity concentration of $4.86{\mu}Ci/cc$ and a true count rate of 519 kcps in 2D. The accuracy of count rate linearity correction was 1.84% at the activity of $4.50{\mu}Ci/cc$. Non-uniformity was 2.06% in 2D and 2.93% in 3D. Remnant errors after scatter correction were 0.55% in 2D and 4.12% in 3D. The errors of attenuation correction were 6.21% (air), 0.20% (water), -6.32% (teflon) in 2D and 5.00% (air), 6.94% (water), 3.01% (teflon) in 3D. The results indicate the performance of GE $Advance^{TM}$ PET scanner to be well suited for clinical and research applications.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.1
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• pp.7-13
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• 2020

Purpose: This study was to evaluate marginal and internal discrepancy of 3-unit fixed dental prostheses (FDP) fabricated by subtractive manufacturing and additive manufacturing. Materials and methods: 3-unit bridge abutments without the maxillary left second premolar were prepared (reference model) and the reference model scan data was obtained using an intraoral scanner. 3-unit fixed dental prostheses were fabricated in the following three ways: Milled 3-unit FDP (MIL), digital light processing (DLP) 3D printed 3-unit FDP (D3P), stereolithography apparatus (SLA) 3D printed 3-unit FDP (S3P). To evaluate the marginal/internal discrepancy and precision of the prosthesis, scan data were superimposed by the triple-scan protocol and the combinations calculator, respectively. Quantitative and qualitative analysis was performed using root mean square (RMS) value and color difference map in 3D analysis program (Geomagic control X). Statistical analysis was performed using the Kruskal-Wallis test (α=.05), MannWhitney U test and Bonferroni correction (α=.05/3=.017). Results: The marginal discrepancy of S3P group was superior to MIL and D3P groups, and MIL and D3P groups were similar. The D3P and S3P groups showed better internal discrepancy than the MIL group, and there was no significant difference between the D3P and S3P groups. The precision was excellent in the order of MIL, S3P, and D3P groups. Conclusion: Within the limitation of this study, the 3-unit fixed dental prostheses fabricated by additive manufacturing showed better marginal and internal discrepancy than the those of fabricated by subtractive manufacturing, but the precision was poor.

• Fashion & Textile Research Journal
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• v.15 no.6
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• pp.977-984
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• 2013

This study classified the type of sole for female high school students and analyzed the characteristics of each type by the shape of the sole (plantar view) using 2D scan data. The data were collected from a foot anthropometry of 310 female high school students in Gwangju and Jeollanam-do. Left feet and right feet were measured indirectly by using flatbed scanner. The sole anthropometric measurements consisted of 24 items. The results of the investigation into the differences between left and right feet soles by the 2D measurements data indicated that there was no significant statistical differences in the length of items. The left sole had higher values than right sole in the width items and angle items; however, the lateral side of the right feet projected to the outside more often than left feet. In analyzing foot sole of female high school students, the shapes of sole were classified into three types. Type 1(41.94%), Type 2(36.77%), Type 3(21.29%). The most characteristic sole type for female high school students was Type 1. Type 1 referred to a narrow foot width with little or no curvature of the toe. Type 2 represented the longest foot, with foot width shown as a spacious and distinctive feature in width at the medial area of the foot. Type 3 represented the shortest and widest of ball width, gathered inside toe 5, and lateral side as the most projected among the three types.

• Journal of Korea Multimedia Society
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• v.15 no.7
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• pp.941-950
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• 2012

A virtual garment fitting system which fits the top and bottom of a garment on 3D body data is introduced. This system uses the laser scanned 3D body data and the digital images photographed the front and back of a garment. The digital images are modeled to reflect tensions among particles in the images and the friction and gravity effects are considered in the fitting process to the body data. When a bottom is fitted, a virtual belt to hold the bottom in the waist is introduced since gravity effects pull down it. Also the process for fitting the top and bottom on layers is proposed here. The system has the strengths that it uses only the front and back image of a garment instead of using complicated patterns of a garment, and provides a realistic fit result as a 3D figure. As on-line retailing shop in present displays front and back images of garments, this system also does. However this system provides a differentiated service to user than present retailing shop as showing a 3D fit image. It will make a new trend in online shop retailing of garment.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.07a
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• pp.135-136
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• 2015

컴퓨터 생성 홀로그램(CGH: computer generated hologram) 기법은 기존의 광학계 장치와 변수들을 수학적으로 모델링하여 일반 범용 컴퓨터(PC: personal computer)로도 디지털 홀로그램을 생성할 수 있는 기술이다. 이 기술은 디지털 홀로그램의 해상도와 3D 물체의 광원 수에 따라 알고리즘의 연산량이 좌우되기 때문에, 실용적인 사용을 위해서 알고리즘의 연산량을 낮추거나 하드웨어의 연산 속도를 높이는 연구가 필수적이다. 본 논문에서는 초다광원 3D 물체의 디지털 홀로그램을 고속으로 생성할 수 있는 방법을 제안한다. 제안하는 방법은 한 개의 서버 PC와 다수의 클라이언트 PC들로 구성되어 있으며, 이들은 일반적으로 사용되는 범용 GPU (graphic processing unit)가 장착되어 있다. 서버에서 3D 물체의 광원을 스캔하여 데이터화 하고, 클라이언트 PC들의 연산 능력에 따라 광원 데이터를 분할하여 클라이언트들에게 각각 전송한다. 각각의 클라이언트들은 전송받은 데이터를 이용해 다중 GPU 기반의 CGH 연산을 수행하여 간섭 패턴들을 생성하고, 생성된 패턴들은 다시 서버 PC로 재전송된다. 서버 PC로 재전송 된 패턴들이 하나로 누적되면 디지털 홀로그램이 생성된다. 본 실험에서, 기존의 방법으로는 139,655개의 광원에 대해 $1,024{\times}1,024$ 해상도의 홀로그램을 생성하는데 약 2,250 ms가 걸린 반면, 제안하는 방법은 약 478 ms의 속도로 생성할 수 있음을 확인하였다.

• Journal of the Korean Society of Radiology
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• v.12 no.7
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• pp.813-819
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• 2018

To demonstrate the 3D usefulness of MDCT, a 73-year-old male patient with subclavian thrombosis was obtained 3D images of maximum intensity projection (MIP), volume rendering, and multiplanar reformation (MPR) to clearly detect and locate the subclavian artery. The data will be provided to the patient for diagnosis and treatment. The scan data were acquired as 3D CT images MIP, volume rendering, curved MPR, and virtual endoscopy images. In the 3D program, the ascending aorta was measured as 364.28 HU, the left carotid artery was 413.77 HU, and the left subclavian artery was 15.72 HU. MIP coronal image shows the closure of the subclavian artery in the left side. Three-dimensional volume images were obtained with 100% permeability and 87-1265 HU. The coronal curved MPR and sagittal curved MPR images show the closure of the subclavian artery due to thrombus using 3D image processing. In the case of subclavian arterial occlusion due to thrombosis, the patient is scanned with MDCT and 3D image processing can be used to confirm occlusion of subclavian artery.

• Journal of the Korea Computer Graphics Society
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• v.17 no.1
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• pp.9-16
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• 2011

In this paper, we describe the development of a system for generating a 3-dimensional human face and predicting it's appearance as it ages over subsequent years using 3D scanned facial data and photo images. It is composed of 3-dimensional texture mapping functions, a facial definition parameter input tool, and 3-dimensional facial prediction algorithms. With the texture mapping functions, we can generate a new model of a given face at a specified age using a scanned facial model and photo images. The texture mapping is done using three photo images - a front and two side images of a face. The facial definition parameter input tool is a user interface necessary for texture mapping and used for matching facial feature points between photo images and a 3D scanned facial model in order to obtain material values in high resolution. We have calculated material values for future facial models and predicted future facial models in high resolution with a statistical analysis using 100 scanned facial models.