• Journal of the Korea Computer Graphics Society
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• v.18 no.3
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• pp.9-16
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• 2012

In this paper, we present a new method for reconstructing detailed facial expression from roughly captured data with a small number of markers. Because of the difference in the required capture resolution between the full-body capture and the facial expression capture, they hardly have been performed simultaneously. However, for generating natural animation, a simultaneous capture for body and face is essential. For this purpose, we provide a method for capturing the detailed facial expression only with a small number of markers. Our basic idea is to build a database for the facial expressions and apply the principal component analysis for reducing the dimensionality. The dimensionality reduction enables us to estimate the full data from a part of the data. We justify our method by applying it to dynamic scenes to show the viability of the method.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.8
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• pp.1187-1193
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• 2013

In this paper, we present realistic 3D head modeling and facial expression systems. For 3D head modeling, we perform generic model fitting to make individual head shape and texture mapping. To calculate the deformation function in the generic model fitting, we determine correspondence between individual heads and the generic model. Then, we reconstruct the feature points to 3D with simultaneously captured images from calibrated stereo camera. For texture mapping, we project the fitted generic model to image and map the texture in the predefined triangle mesh to generic model. To prevent extracting the wrong texture, we propose a simple method using a modified interpolation function. For generating 3D facial expression, we use the vector muscle based algorithm. For more realistic facial expression, we add the deformation of the skin according to the jaw rotation to basic vector muscle model and apply mass spring model. Finally, several 3D facial expression results are shown at the end of the paper.

• Journal of Information Display
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• v.6 no.4
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• pp.26-34
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• 2005

In this paper, a new rectification scheme to transform the uncalibrated stereo image pair into the calibrated one is suggested and its performance is analyzed by applying this scheme to the reconstruction of the intermediate views for multi-view stereoscopic display. In the proposed method, feature points are extracted from the stereo image pair by detecting the comers and similarities between each pixel of the stereo image pair. These detected feature points, are then used to extract moving vectors between the stereo image pair and the epipolar line. Finally, the input stereo image pair is rectified by matching the extracted epipolar line between the stereo image pair in the horizontal direction. Based on some experiments done on the synthesis of the intermediate views by using the calibrated stereo image pairs through the proposed rectification algorithm and the uncalibrated ones for three kinds of stereo image pairs; 'Man', 'Face' and 'Car', it is found that PSNRs of the intermediate views reconstructed from the calibrated images improved by about 2.5${\sim}$3.26 dB than those of the uncalibrated ones.

• The Journal of the Korea Contents Association
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• v.15 no.11
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• pp.313-321
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• 2015

To minimize CT examination for Hip FAI diagnosis and operation plan. also, whether the MRI 3D images can replace Hip Clock face image was evaluated when performing Hip FAI MRI by using additional 3D image. This study analyzed Hip MRI and 3D Hip CT images of 31 patients in this hospital. For the purpose of evaluating the images, one orthopedic surgeon and one radiology specialist reconstructed Clock face, at MR and CT modality, by superior 12 o'clock, labrum front 3 o'clock, and the other side 9 o'clock, centering on Hip joint articular transverse ligament 6 o'clock. Afterwards, by the Likert Scale 5 point scale (independent t-test p<0.005), this study evaluated the check-up of A. retinacular vessel, B. head neck junction at 11 o'clock, A. Epiphyseal line, B. Cam lesion at 12 o'clock, and Cam lesion, Posterior Cam lesion at 1,2,3 and 4 o'clock. As for the verification of reliability among observers, this study verified coincidence by Cohen's weighted Kappa verification. As a result of Likert scale for the purpose of qualitative evaluation about the image, 11 o'clock A. retinacular vessel MR average was $3.69{\pm}1.0$ and CT average was $2.8{\pm}0.78$. B. head neck juncton didn't have a difference between two observers (p <0.416). 12 o'clock A. Epiphyseal line MR average was $3.54{\pm}1.00$ and CT average was $4.5{\pm}0.62$(p<0.000). B. Cam lesion didn't have a difference between two observers (p <0.532). 1,2,3,4 Cam lesion and Posterior Cam lesion were not statistically significant (p <0.656, p <0.658). As a result of weighted Kappa verification, 11 o'clock A.retinacular vessel CT K value was 0.663 and the lowest conformity. As a result of coincidence evaluation on respective item, a very high result was drawn, and two observers showed high reliability.

• Archives of Craniofacial Surgery
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• v.16 no.2
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• pp.58-62
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• 2015

Background: Age-related changes have been studied for lower and middle facial bones. Although the forehead comprises one-third of the facial area, no studies have investigated age-related changes in the upper part of the face or forehead. The purpose of this study was to use three-dimensional computed tomography (3D CT) to investigate age-related changes in the frontal bone. Methods: A retrospective review was performed for patients who underwent 3D CT scan of facial bones. Patients were divided by gender and age (20 to 40 years, 41 to 60 years, and above 60 years). The frontal bone curvature was evaluated by the length of frontal bone and by two frontal bone angles in relation to the Frankfurt horizon. Results: In both genders, aging was associated with increasing lower slope length. In elderly men (>60 years), the upper slope angle was significantly higher when compared to younger male subjects. Women demonstrated similar age-related changes, but the differences were only statistically significant for the middle and older age groups. Conclusion: This study demonstrates quantifiable age-related changes in the frontal bone. These findings contribute to the understanding of age-related changes of the facial soft tissues. The mean measurements in each age group can be used as a reference when planning forehead reconstruction.

• Journal of Cadastre & Land InformatiX
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• v.52 no.2
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• pp.171-187
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• 2022

Recently, the demand and development for non-face-to-face services are rapidly progressing due to the pandemic caused by the COVID-19, and attention is focused on the metaverse at the center. Entering the era of the 4th industrial revolution, Metaverse, which means a world beyond virtual and reality, combines various sensing technologies and 3D reconstruction technologies to provide various information and services to users easily and quickly. In particular, due to the miniaturization and economic increase of convergence sensors such as unmanned aerial vehicle(UAV) capable of high-resolution imaging and high-precision LiDAR(Light Detection and Ranging) sensors, research on digital-Twin is actively underway to create and simulate real-life twins. In addition, Game engines in the field of computer graphics are developing into metaverse engines by expanding strong 3D graphics reconstuction and simulation based on dynamic operations. This study constructed a mirror-world type metaverse that reflects real-world coordinate-based reality using Unreal Engine 5, a recently announced metaverse engine, with accurate 3D spatial information data of convergence sensors based on unmanned aerial system(UAS) and LiDAR. and then, spatial information contents and simulations for users were produced based on various public data to verify the accuracy of reconstruction, and through this, it was possible to confirm the construction of a more realistic and highly utilizable metaverse. In addition, when constructing a metaverse that users can intuitively and easily access through the unreal engine, various contents utilization and effectiveness could be confirmed through coordinate-based 3D spatial information with high reproducibility.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10c
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• pp.459-464
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• 2007

영상기반의 3자원 복원(reconstruction)에 대한 연구가 컴퓨터 성능의 발전과 다양한 영상기반의 복원 알고리즘의 연구로 인해 최근 좋은 결과를 보이고 있으나, 이는 얼굴영역과 같은 목적이 되는 영역이 각 입력영상으로부터 미리 정확하게 추출되어 있다고 가정하기 때문이다. 일반적으로 목적이 되는 영역을 추출하기 위해 차영상이 많이 이용되고 있지만 차영상은 잡음과 구멍(hole)과 같은 오 추출된 영역이 발생하기 때문에 목적이 되는 영역을 3차원으로 복원을 할 때 심각한 오류를 초래할 수 있다. 전경물체(목적이 되는 영역)을 정확하게 추출하기 위해 최근 그래프 컷(graph cut)을 이용한 방법이 다양하게 시도되고 있다. 그래프 컷은 데이터 항(data term)과 스무드 항(smooth term)으로 구성된 에너지 함수를 전역적으로 최소화하는 방법으로 여러 공학적 문제에서 좋은 결과를 보이고 있지만, 에너지 함수의 데이터 항을 설정할 때 필요한 사전정보를 자동으로 얻기가 어렵다. 스테레오 비전의 깊이 정보가 최근 전경 물체 추출을 위한 사전정보로 많이 이용되고 있고 그들의 실험환경에서는 좋은 결과를 보이지만, 3차원 얼굴 복원에서 얼굴의 대부분이 동질의 영역을 가지고 있기 때문에 깊이 정보를 구하기 어려워 정확한 사전정보를 구하기가 어렵다. 본 논문에서는 3차원 얼굴 복원을 효과적으로 하기 위한 그래프 컷 기반의 전경 물체 추출 방법을 제안한다. 에너지 함수의 데이터 항을 설정하기 위해 전경 물체에 대한 사전정보를 추출해야 하며, 이를 위해 차영상을 이용하여 대략적인 전경 물체 추출하고, 사전정보에 대한 오류를 줄이기 위해 잡음과 그림자 영역을 제거한다. 잡음과 그림자 영역을 제거하면 구멍이 발생하거나 실루엣이 손상되는 문제가 발생한다. 손상된 정보는 근접한 픽셀이 유사하지 않을 때 낮은 비용을 할당하는 에너지 함수의 스무드(smooth) 항에 의해 에지 정보를 기반으로 채워진다. 결론적으로 제안된 방법은 스무드 항과 대략적으로 설정된 데이터 항으로 구성된 에너지 함수를 그래프 컷으로 전역적으로 최소화함으로써 더욱 정확하게 목적이 되는 영역을 추출할 수 있다.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.4
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• pp.123-130
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• 2018

Triangulation is one of the fundamental problems in computational geometry and computer graphics community, and it has huge application areas such as 3D printing, computer-aided engineering, surface reconstruction, surface visualization, and so on. The Delaunay refinement algorithm is a well-known method to generate quality triangular meshes when point cloud and/or constrained edges are given in two- or three-dimensional space. In this paper, we propose a simple but efficient algorithm to triangulate Voronoi surfaces of Voronoi diagram of spheres in 3-dimensional Euclidean space. The proposed algorithm is based on the Ruppert's Delaunay refinement algorithm, and we modified the algorithm to be applied to the triangulation of Voronoi surfaces in two ways. First, a new method to deciding the location of a newly added vertex on the surface in 3-dimensional space is proposed. Second, a new efficient but effective way of estimating approximation error between Voronoi surface and triangulation. Because the proposed algorithm generates a triangular mesh for Voronoi surfaces with guaranteed quality, users can control the level of quality of the resulting triangulation that their application problems require. We have implemented and tested the proposed algorithm for random non-intersecting spheres, and the experimental result shows the proposed algorithm produces quality triangulations on Voronoi surfaces satisfying the quality criterion.

• Archives of Plastic Surgery
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• v.38 no.3
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• pp.295-299
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• 2011

Purpose: It is generally believed that alopecia is caused by various factors such as scars, stress, genetical factors, androgens, etc. Androgenic alopecia is one of the most common cause of alopecia and found mainly in males. Propecia (Merck & Co., USA) and Minoxidil (McNEIL-PPC, Inc, USA) were the drugs approved from FDA for treatment of androgenic alopecia. Surgical treatments such as flap, tissue expansion, scalp reduction and hair transplantation can be considered if necessary. Hair micrograft techniques were developed for natural hair shapes and minimal adverse effect. There were attempts to measure the length of the forehead of the Korean young adults. However attempts to classify the shape and location of forehead hairline were rare. This study attempted to find out standard hairlines of young adults in their 20s & 30s and the result would be the guideline of the hairline in hair replacement surgery of male patients in their 40s & 50s. Methods: 200 male adults in 20s and 30s were photographed and measured the length of 11 vertical index lines to determine hairline. The indexes are the distances from hairline to intercanthal midpoint (A), to medial canthus (B), to upper eyelid fissure (C), to lower eyelid fissure (D), to lateral canthus (E) and distance from lateral highest point to medial lowest point, if the hairline is M-shape (F). Additionally, we classified the hairlines into 4 groups, M, horizontal, inverted U and irregular shapes. Results: The most common hairline of male adults in their 20s is inverted U-shape (53.3%), followed by horizontal-shape, M-shape, irregular-shape. In their 30s, inverted U-shape (59%) is followed by irregular-shape, M-shape, horizontal-shape. The M-shape is more frequently found in males in 30s than those in 20s. The mean values of the indexes in their 20s are as follows: A (76.14 mm), B (Rt: 75.78 mm, Lt:76.41 mm), C (Rt: 69.43 mm, Lt: 69.92 mm), D (Rt: 76.92 mm, Lt:77.46 mm), E (Rt: 64.16 mm, Lt: 64.73 mm), F (4.09 mm). Those in their 30s are as follows: A (76.13 mm), B (Rt: 76.114 mm, Lt: 76.02 mm), C (Rt: 69.87 mm, Lt: 70.37 mm), D (Rt: 77.37 mm, Lt: 77.58 mm), E (Rt: 69.63 mm, Lt: 69.85 mm), F (6.14 mm). Conclusion: The knowledge about human body measurement is indispensable to plastic surgeons. In this study, inverted U shape is the most common type of hairline in 30s, and similar distribution is found in 20s. The percentage of M shape in their 30s is elevated more than 10% compared to that in their 20s. The study of hairline shapes and 11 indexes of hairlines can be useful for planning of the hair transplantation and postoperative evaluation. This study being based on photogrammetry, there may be differences between actual distance of curved face and projected distance on flat photographs.

• Journal of the Korean Geosynthetics Society
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• v.15 no.2
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• pp.55-64
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• 2016

The construction of the road NATM tunnel, which undergoes the weathered zone of the mountain, was in process with the reinforcement methods such as the rock bolt, shotcrete depositing, and the multi step grout with large diameter steel pipe. The collapse from the ceiling, and on the ground surface area(sink hole), of which were measured to be 25m from the ground surface($V=12m(W){\times}14m(L){\times}5m(H)=840m^3$), as well as excessive displacements in the tunnel, had occurred. In order to execute the necessary reconstruction work, the causes of the surface collapses were inspected through the field investigation, in-situ tests, and numerical analysis. As a result, several proper solutions were suggested for both internal and external reinforcements for the tunnel. As a result of numerical analysis, the collapsed zone of the tunnel was reinforced up to 0.5D~1.0D laterally by the cement grouting on the ground surface, 0.5D longitudinally by the multi step grout with large diameter steel pipe in tunnel. With further reinforcement implemented by rebars in lining, the forward horizontal boring was executed to the rest of the tunnel to evaluate the overall status of the tunnel face. Appropriate reinforcement methods were provided if needed.