• Title/Summary/Keyword: Curve reconstruction

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A Study on the Edge Construction of CMM Data Using a Method of Mean Curvature Block (평균곡률 구간법을 이용한 CMM 데이터의 경계 형성 연구)

  • Chang, Byoung-Chun;Kim, Dae-Il;Oh, Seok-Hyung
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.9 no.1
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    • pp.74-80
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    • 2010
  • The purpose of reverse engineering design using 3D measurement data is an accurate reconstruction of real body. In oder to accomplish this object, it is important that creating exact extracting edges should be studying out first of all. This study used edge-based method to find out edge point from the measuring point data. The characteristics are analysed using the mean curvature block method on the fitting NURBS curve and defined edges through block removal condition. The results showed that only using the NURBS curve of maximum curvature analysis to define correct edge of real geometry is limited, but this segmentation approach provides simplified necessary condition for edge classification, and an effectiveness to classify a straight line, curves and fillets etc.

The Measurement of Size of the Pedicle Using 3 Dimensional Reconstruction Image in Idiopathic Scoliosis (특발성 척추측만증 환자에서의 3차원적 재구성을 이용한 척추경의 크기 측정)

  • Heo, Jae-Hee;Ahn, Myun-Hwan
    • Journal of Yeungnam Medical Science
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    • v.21 no.1
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    • pp.40-50
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    • 2004
  • Background: This study was conducted to analyze the height and width of the pedicle of the upper and lower levels on the concave and the convex sides. In addition, we checked for the appropriate pedicle screw size which could be screwed in without complications. Materials and Methods: Taking a simple AP radiography in a standing position, 99 vertebrae on the major curve with the possibility of 3-D reconstruction were analyzed after checking the CT in a supine position of 22 idiopathic scoliosis. We measured Cobb's angle from a simple radiograph, and measured the size of the isthmus by the Inner Space 3-D Editor after 3-D reconstruction with the Inner Space 3-D program in the DICOM file transformed from CT image. We then analyzed the size of pedicles of the upper and lower levels on the concave and the convex sides by measuring the height and width of the pedicle. Results: All pedicles on the concave side were smaller than those on the convex side. Their size increased as the measurement moved from the upper to lower vertebra, except for the upper thoracic vertebra. When the width of the pedicle through 3-D reconstruction was compared with the narrowest width of the pedicle measured by using CT, the width of the pedicles through 3-D reconstruction was statistically smaller (P<0.01). Most of the pedicles were tear-drop or kidney shaped rather than cylindrical. Conclusion: These results suggest that the use of the coronal plane through 3-D reconstruction would be necessary for an accurate measurement of the size of the pedicle. It is important to pay careful attention to the screw size and the screwing method considering the pedicle shape through 3-D reconstruction.

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Polar-coordinates Linear Interpolation for Contour Reconstruction at Summit Area (정상 근방의 등고선 재구성을 위한 극좌표계 선형 보간)

  • 박천주;전병민
    • Proceedings of the Korea Contents Association Conference
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    • 2003.11a
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    • pp.407-413
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    • 2003
  • To connect the gap on the contours at the summit area, we propose the linear interpolation in the polar coordinates. The results of appling both existing algorithms and proposed method to some graphic images, the proposed interpolation method was superior. Also by generating a new curve having similar appearance of neighboring contours, the connected contours were reconstructed naturally.

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Segmentation of 3D Visible Human Color Images by Balloon (Balloon을 이용한 3차원 Visible human 컬러 영상의 분할 방법)

  • 김한영;김동성;강흥식
    • Proceedings of the IEEK Conference
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    • 2001.06e
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    • pp.73-76
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    • 2001
  • A segmentation is a prior processing for medical image analysis and 3D reconstruction. This Paper provides the method to segment 3D Visible Human color images. Firstly, the reference images that have a initial curve are segmented using Balloon and the results are propagated to the adjacent images. In the propagation processing, the result of the adjacent slice is modified by Edge-limited SRG Finally, the 3D Balloon improves the segmentation results of each 2D slice. the proposed method's performance was verified through the experiments to segment thigh muscles of Visible Human color images.

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Data Structure Extraction of Boundary Segments by Region Labeling (영역 라벨링에 의한 경계선 세그먼트의 데이터 구조 추출)

  • 최환언;정광웅;김두영
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.17 no.1
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    • pp.80-89
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    • 1992
  • This paper presents algorithms which are region labeling and data structure of a boundary segmentation as image intermediate description process. In the method, the algorithms are region labeling, boundary segmentation, line and curve fitting and extracting data structure of each segment. As a result, a data structure of image is described by a set of region number, segment number, line or curve, starting point and end point of each segment and coefficient of line or curve. These data structures would serve for higher level processing as object recognition. For example we will use this data structure to solve the correspondence problem of stereoscopic image information. And we verified these algorithms through the image reconstruction of data structure.

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Modified Design of Anterolateral Thigh Free Flap for Hypopharyngeal Reconstruction (하인두 재건을 위한 전외측 대퇴부 유리 피판의 변형된 도안)

  • Kim, Sung-Chan;Kim, Eun-Key
    • Archives of Reconstructive Microsurgery
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    • v.21 no.1
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    • pp.14-20
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    • 2012
  • Purpose: Defect after ablation of hypopharyngeal cancer often requires reconstruction by free tissue transfer. Since neo-hypopharynx is totally buried, various methods have been suggested for monitoring. We propose a modified design of anterolateral thigh (ALT) free flap for reconstruction of pharyngolaryngectomy defect, which has an exteriorized part for clinical monitoring and allows for primary closure. Materials and Methods: Three consecutive patients with hypopharyngeal cancer were reconstructed with ALT flap with modified design: 1) distal part of flap was elongated into fusiform shape and used as exteriorized monitoring segment with a deepithelized bridge and 2) proximal part was designed as curve so the maximum width of the flap was reduced to less than 10 cm. Results: Patient 1, 2 had uneventful postoperative course with healthy skin color and fresh pin prick bleeding. In patient 3, defect after cancer ablation was shorter than usual and deepithelized bridge was longer. When the general hemodynamic status of the patient was aggravated in postoperative course, the color of monitoring skin was changed. Viability of the whole flap was confirmed by endoscopy. However, leakage developed after 3 weeks and repair was necessary. In all patients the donor sites were closed primarily. Conclusion: By the modified design of ALT flap, clinical monitoring can be possible by examining exteriorized monitoring flap and also donor site can be closed primarily. However possibility of false positive exists and technical caution and patient selection is needed because of danger of leakage.

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A STUDY ON THE ANALYSIS OF THE CURVE OF SPEE ON THE GNATHOLOGICAL CAST AND THE CEPHALOMETRIC RADIOGRAPH (악태모형과 측모두부 계측 방사선 사진상 스피만곡 분석에 관한 연구)

  • Choi, Ah-Young;Kim, Jeong-Sun;Kay, Kee-Sung
    • The Journal of Korean Academy of Prosthodontics
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    • v.36 no.2
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    • pp.323-335
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    • 1998
  • Clinically, the curve of Spee is widely applied as a determined level of the occlusal curvature when the oral rehabilitation and the reconstruction of the prosthesis is needed at the malalignment dentition due to the missing, extrusion, and the inclination of the teeth. The purpose of this study was to analyze the curve of Spee of the occlusal curvature which influences to the occlusal form and the location three dimensionally, and then was to measure the radius and the degree of curvature of the curve of Spee and also was to investigate the influence to the cuspal inclination according to the change of the inclination of the curve of Spee which was analyzed by AutoCAD R.13 program at the gnathological cast and the cephalometric radiograph. The following results were obtained : 1. The radius of the curve of Spee was the mean of $11.74{\pm}3.64cm$ in the model, $12.75{\pm}4.63cm$ in the radiograph and there was no significant difference statistically between the model and the radiograph(P>0.001). 2. The radius and the degree of curvature of the curve of Spee showed negative correlation(r=-0.80), while the radius and the degree of curvature of the curve of Spee in relation to the length of the curve of Spee did not show correlation. 3. The case of the curve of Spee inclined to the posterior, that is. $Post.M{\theta}$ group showed the mean of $4.73{\pm}3.64$, positive correlation to the P2m, M1mm, M1dm, M2dm, and especially the greatest correlation coefficient to the mesial inclination angle of the mesio-buccal cusp tip of the first molar(r=0.70). 4. The case of the curve of Spee inclined to the anterior, that is, $Ant.M{\theta}$ group showed the mean of $3.28{\pm}3.59$, positive correlation to the P2m, M1mm, and also the greatest correlation coefficient to the mesial inclination angle of the mesio-buccal cusp tip of the first molar(r=0.78

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A Study on the Historical Reconstruction of Corps à Baleine in 18th Century France (18세기 프랑스 꼬르 아 발렌느(corps à baleine) 고증제작 연구)

  • Kim, Yang-Hee;Na, Young-Joo;Kim, Hyun-Joo
    • Journal of the Korean Society of Clothing and Textiles
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    • v.35 no.8
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    • pp.991-1005
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    • 2011
  • This study researches the historical production, process, and design method for 3 pairs of corsets in $18^{th}$ century France. In the analytical stage of historical materials, it grasped the kind, form, origin, and change in style through a lexical definition of relevant terms. Through a precedent study on Garsault's 'L'art du tailleur', preservation costume, and historical reconstruction of pattern in preservation costume, it confirmed corps size, silhouette, pattern form, and material for historical production. The sewing method and the producing sequence were analyzed. In the production stage, 3 selective models in corps plein baleine, corps demi-baleine, and corset were historically produced. With neckline of forming broad Letter U, the bust part is covered roundly. The bodice was composed of 10 panels based on the corps form in the mid-$18^{th}$ century of following a curve of a human body. A shoulder strap was allowed to make the arm movement comfortable by producing and attaching it separately. The cutting line except the center in the front and the back of vertical line was distributed according to the natural flow of a form and movement of the human body. The curve-based pattern line was confirmed.

Systematic Review of Reciprocal Changes after Spinal Reconstruction Surgery : Do Not Miss the Forest for the Trees

  • Kim, Chang-Wook;Hyun, Seung-Jae;Kim, Ki-Jeong
    • Journal of Korean Neurosurgical Society
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    • v.64 no.6
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    • pp.843-852
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    • 2021
  • The purpose of this review was to synthesize the research on global spinal alignment and reciprocal changes following cervical or thoracolumbar reconstruction surgery. We carried out a search of PubMed, EMBASE, and Cochrane Library for studies through May 2020, and ultimately included 11 articles. The optimal goal of a truly balanced spine is to maintain the head over the femoral heads. When spinal imbalance occurs, the human body reacts through various compensatory mechanisms to maintain the head over the pelvis and to retain a horizontal gaze. Historically, deformity correction has focused on correcting scoliosis and preventing scoliotic curve progression. Following substantial correction of a spinal deformity, reciprocal changes take place in the flexible segments proximal and distal to the area of correction. Restoration of lumbar lordosis following surgery to correct a thoracolumbar deformity induces reciprocal changes in T1 slope, cervical lordosis, pelvic shift, and lower extremity parameters. Patients with cervical kyphosis exhibit different patterns of reciprocal changes depending on whether they have head-balanced or trunk-balanced kyphosis. These reciprocal changes should be considered to in order to prevent secondary spine disorders. We emphasize the importance of evaluating the global spinal alignment to assess postoperative changes.

Reconstruction of the Medial Canthus Using an Ipsilateral Paramedian Forehead Flap

  • Kim, Jin Hyung;Kim, Jeong Min;Park, Jang Wan;Hwang, Jae Ha;Kim, Kwang Seog;Lee, Sam Yong
    • Archives of Plastic Surgery
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    • v.40 no.6
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    • pp.742-747
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    • 2013
  • Background The medial canthus is an important area in determining the impression of a person's facial appearance. It is composed of various structures, including canthal tendons, lacrimal canaliculi, conjunctiva, the tarsal plate, and skin tissues. Due to its complexity, medial canthal defect reconstruction has been a challenging procedure to perform. The contralateral paramedian forehead flap is usually used for large defects; however, the bulkiness of the glabella and splitting at the distal end of the flap are factors that can reduce the rate of flap survival. We reconstructed medial canthal defects using ipsilateral paramedian forehead flaps, minimizing glabellar bulkiness. Methods This study included 10 patients who underwent medial canthal reconstruction using ipsilateral paramedian forehead flaps between 2010 and 2012. To avoid an acute curve of the pedicle, which can cause venous congestion, we attempted to make the arc of the pedicle rounder. Additionally, the pedicle was skeletonized from the nasal root to the glabella to reduce the bulkiness. Results All patients had basal cell carcinoma, and 3 of them had recurrent basal cell carcinoma. All of the flaps were successful without total or partial flap loss. Two patients developed venous congestion of the flap, which was healed using medicinal leeches. Four patients developed epiphora, and 2 patients developed telecanthus. Conclusions Large defects of the medial canthus can be successfully reconstructed using ipsilateral paramedian forehead flaps. In addition, any accompanying venous congestion can be healed using medicinal leeches.