• 제목/요약/키워드: Curve Reconstruction

검색결과 70건 처리시간 0.021초

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

  • 장병춘;김대일;오석형
    • 한국기계가공학회지
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    • 제9권1호
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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.

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

  • 허재희;안면환
    • Journal of Yeungnam Medical Science
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    • 제21권1호
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    • pp.40-50
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    • 2004
  • 특발성 척추측만증 환자에서 3차원적인 재구성을 이용한 관상면에서 척추경의 폭을 측정하는 것이 오차를 줄일 수 있는 방법이고 척추경 나사못의 삽입 시 척추경의 크기를 술 전에 측정한 후 그 값의 최대치보다 작은 최대 크기의 원추형 나사못을 삽입하는 것이 안전한 방법이라 사료된다. 척추경 나사못을 삽입할 시에는 척추경의 모양이 원주 형태가 아닌 낙루 형태나 신장 형태 등 추체마다의 다양한 모양을 고려하여 나사못 크기와 삽입 방법에 세심한 주의가 필요할 것으로 사료된다.

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

  • 박천주;전병민
    • 한국콘텐츠학회:학술대회논문집
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    • 한국콘텐츠학회 2003년도 추계종합학술대회 논문집
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    • pp.407-413
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    • 2003
  • 본 연구에서는 산악지의 정상 근방의 등고선 상에 존재하는 끊김을 연결하기 위한 극좌표계 선형 보간방법을 제안한다. 그래픽 영상에 대해 기존의 재구성 알고리즘들과 성능을 비교한 결과, 제안된 극좌표계선형 보간이 인접 등고선의 외형과 유사한 선분을 생성함에 의해 자연스러운 등고선을 재구성하는 것으로 나타났다.

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

  • 김한영;김동성;강흥식
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2001년도 하계종합학술대회 논문집(5)
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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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영역 라벨링에 의한 경계선 세그먼트의 데이터 구조 추출 (Data Structure Extraction of Boundary Segments by Region Labeling)

  • 최환언;정광웅;김두영
    • 한국통신학회논문지
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    • 제17권1호
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    • pp.80-89
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    • 1992
  • 화상처리는 전처리, 중간표현, 최종 인식의 3단계로 구분하여 처리할 수 있다. 본 논문에서는 전처리 단계에서 구해진 에지로 둘러싸인 예영역들로부터 라벨링 기법으로 화상을 구분된 영역의 집합으로 표현한 후 각 영역을 둘러 싸고있는 외측 경계과 내측 경계를 세그먼트화하여 각 세그먼트들에 대한 영역의 정보, 세그먼트 번호, 시작점과 끝점의 정보, 적용된 직선 곡선의 종류 및 이들의 개수 정보 리스트에 대한 데이터 구조를 만드는 중간 표현 단계에 대한 알고리즘을 제안하고, 구해진 데이타 구조를 이용 화상을 재구성한 결과 오차가 한 화소 범위내의 신뢰성이 있음을 확인하였다.

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

  • 김성찬;김은기
    • Archives of Reconstructive Microsurgery
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    • 제21권1호
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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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악태모형과 측모두부 계측 방사선 사진상 스피만곡 분석에 관한 연구 (A STUDY ON THE ANALYSIS OF THE CURVE OF SPEE ON THE GNATHOLOGICAL CAST AND THE CEPHALOMETRIC RADIOGRAPH)

  • 최아영;김정선;계기성
    • 대한치과보철학회지
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    • 제36권2호
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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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18세기 프랑스 꼬르 아 발렌느(corps à baleine) 고증제작 연구 (A Study on the Historical Reconstruction of Corps à Baleine in 18th Century France)

  • 김양희;나영주;김현주
    • 한국의류학회지
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    • 제35권8호
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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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    • 제64권6호
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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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    • 제40권6호
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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.