• Title, Summary, Keyword: MeshLab

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A Two-Phase Approach of Progressive Mesh Reconstruction from Unorganized Point Clouds

  • Zhang, Hongxin;Liu, Hua;Hua, Wei;Bao, Hujun
    • International Journal of CAD/CAM
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    • v.7 no.1
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    • pp.103-112
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    • 2007
  • This paper presents a practical approach for surface reconstruction from unoriented point clouds. Instead of estimating local surface orientation, we first generate a set of depth images from the input point clouds, and a coarse mesh is then generated based on them by space carving techniques. The resultant mesh is progressively refined by local mesh refinement and optimization according to surface distance measure. A manifold mesh approximating the input points within an given tolerance is finally obtained. Our approach is easy to implement, but has the ability to outputs high quality meshes in different resolutions. We show that the proposed approach is not sensitive to several types of data disfigurement and is able to reconstruct models robustly from variance input data.

Active-Matrix Field Emission Display Based on CNT Emitter and a-Si TFT

  • Song, Yoon-Ho;Kim, Kwang-Bok;Hwang, Chi-Sun;Lee, Sun-Hee;Park, Dong-Jin;Lee, Jin-Ho;Kang, Kwang-Yong;Hur, Ji-Ho;Jang, Jin
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.923-926
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    • 2004
  • Active-matrix field emission display (AMFED) based on carbon nanotube (CNT) emitter and amorphous silicon thin-film transistor (a-Si TFT) is reviewed. The AMFED pixels consisted of a high-voltage a-Si TFT and mesh-gated CNT emitters. The developed AMFED panel showed a high performance with a driving voltage of below 15 V. The low-cost and large-area AMFED approach with a metal mesh technology will be discussed.

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Rack Force Estimation Method using a Tire Mesh Model (TIRE MESH 모델을 활용한 랙추력 추정법 개발)

  • Kim, Minjun;Chang, Sehyun;Lee, Byungrim;Park, Youngdae;Cho, Hyunseok
    • Transactions of the Korean Society of Automotive Engineers
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    • v.22 no.3
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    • pp.130-135
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    • 2014
  • In this paper, a new estimation method is proposed to calculate steering rack axial force using a 3 dimensional tire mesh model when a car is standing on the road. This model is established by considering changes of camber angle and contact patch between the tires and the ground according to steering angle. The steering rack bar axial force is estimated based on the static equilibrium equations of forces and moments. A tire friction force is supposed to act on the center point of the contact patch, and the proportional coefficient of friction depending on contact patch is suggested. Using the proposed estimation method, rack axial force sensitivity analysis is evaluated according to changes of suspension geometry. Then optimal motor power of Motor Driven Power Steering(MDPS) is evaluated using suggested rack forces.

TRIANGLE MESH COMPRESSION USING GEOMETRIC CONSTRAINTS

  • Sim, Jae-Young;Kim, Chang-Su;Lee, Sang-Uk
    • Proceedings of the IEEK Conference
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    • pp.462-465
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    • 2000
  • It is important to compress three dimensional (3D) data efficiently, since 3D data are too large to store or transmit in general. In this paper, we propose a lossless compression algorithm of the 3D mesh connectivity, based on the vertex degree. Most techniques for the 3D mesh compression treat the connectivity and the geometric separately, but our approach attempts to exploit the geometric information for compressing the connectivity information. We use the geometric angle constraint of the vertex fanout pattern to predict the vertex degree, so the proposed algorithm yields higher compression efficiency than the conventional algorithms.

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S-Octree: An Extension to Spherical Coordinates

  • Park, Tae-Jung;Lee, Sung-Ho;Kim, Chang-Hun
    • Journal of Korea Multimedia Society
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    • v.13 no.12
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    • pp.1748-1759
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    • 2010
  • We extend the octree subdivision process from Cartesian coordinates to spherical coordinates to develop more efficient space-partitioning structure for surface models. As an application of the proposed structure, we apply the octree subdivision in spherical coordinates ("S-Octree") to geometry compression in progressive mesh coding. Most previous researches on geometry-driven progressive mesh compression are devoted to improve predictability of geometry information. Unlike this, we focus on the efficient information storage for the space-partitioning structure. By eliminating void space at initial stage and aligning the R axis for the important components in geometry information, the S-Octree improves the efficiency in geometry information coding. Several meshes are tested in the progressive mesh coding based on the S-Octree and the results for performance parameters are presented.

A Novel Shared Segment Protection Algorithm for Multicast Sessions in Mesh WDM Networks

  • Lu, Cai;Luo, Hongbin;Wang, Sheng;Li, Lemin
    • ETRI Journal
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    • v.28 no.3
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    • pp.329-336
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    • 2006
  • This paper investigates the problem of protecting multicast sessions in mesh wavelength-division multiplexing (WDM) networks against single link failures, for example, a fiber cut in optical networks. First, we study the two characteristics of multicast sessions in mesh WDM networks with sparse light splitter configuration. Traditionally, a multicast tree does not contain any circles, and the first characteristic is that a multicast tree has better performance if it contains some circles. Note that a multicast tree has several branches. If a path is added between the leave nodes on different branches, the segment between them on the multicast tree is protected. Based the two characteristics, the survivable multicast sessions routing problem is formulated into an Integer Linear Programming (ILP). Then, a heuristic algorithm, named the adaptive shared segment protection (ASSP) algorithm, is proposed for multicast sessions. The ASSP algorithm need not previously identify the segments for a multicast tree. The segments are determined during the algorithm process. Comparisons are made between the ASSP and two other reported schemes, link disjoint trees (LDT) and shared disjoint paths (SDP), in terms of blocking probability and resource cost on CERNET and USNET topologies. Simulations show that the ASSP algorithm has better performance than other existing schemes.

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Preprocessing Method for Efficient Compression of Patch-based Image (패치 영상의 효율적 압축을 위한 전처리 방법)

  • Lee, Sin-Wook;Lee, Sun-Young;Chang, Eun-Youn;Hur, Nam-Ho;Jang, Euee-S.
    • Journal of Broadcast Engineering
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    • v.13 no.1
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    • pp.109-118
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    • 2008
  • In mapping a texture image into a 3D mesh model for photo-realistic graphic applications, the compression of texture image is as important as geometry of 3D mesh. Typically, the size of the (compressed) texture image of 3D model is comparable to that of the (compressed) 3D mesh geometry. Most 3D model compression techniques are to compress the 3D mesh geometry, rather than to compress the texture image. Well-known image compression standards (i.e., JPEG) have been extensively used for texture image compression. However, such techniques are not so efficient when it comes to compress an image with texture patches, since the patches are little correlated. In this paper, we proposed a preprocessing method to substantially improve the compression efficiency of texture compression. From the experimental results, the proposed method was shown to be efficient in compression with a bit-saving from 23% to 45%.

Influence of the Mold Temperature on the Castability of CP Ti (주형온도가 CP Ti의 주조성에 미치는 영향)

  • Jung, Jong-Hyun;Joo, Kyu-Ji;Go, Eun-Kyoung
    • The Journal of Korean Academy of Dental Technology
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    • v.28 no.1
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    • pp.9-17
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    • 2006
  • The purpose of this study was to evaluate the titanium castability with a spin type casting machine(TiCast, Super R, Selec, Osaka. Japan). We tested phosphate bonded investment "Rematitan$^{(R)}$Plus(Dentaurum, Inc., Pforzheim, Germany)"of mesh grid pattern and plate pattern. Four different mold temperatures(room temperature, 200$^{\circ}C$, 400$^{\circ}C$ and 600$^{\circ}C$) were prepared for the present study. In mesh grid pattern with spruing of $\varphi$0.88㎜ dimeter, when the mold temperature increased, high percentage of castability was gained. Mold temperature showed a highly significant(p<0.05) correlation on the castability, In plate pattern, the higher the mold temperature during casting, the greater the adhesive phenomenon between Ti surface and the investment.

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Helical gear multi-contact tooth mesh load analysis with flexible bearings and shafts

  • Li, Chengwu;He, Yulin;Ning, Xianxiong
    • Structural Engineering and Mechanics
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    • v.55 no.4
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    • pp.839-856
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    • 2015
  • A multi-contact tooth meshing model for helical gear pairs considering bearing and shaft deformations is proposed. First, to easily incorporate into the system model, the complicated Harris' bearing force-displacement relationship is simplified applying a linear least square curve fit. Then, effects of shaft and bearing flexibilities on the helical gear meshing behavior are implemented through transformation matrices which contain the helical gear orientation and spatial displacement under loads. Finally, true contact lines between conjugated teeth are approximated applying a modified meshing equation that includes the influence of tooth flank displacement on the tooth contact induced by shaft and bearing displacements. Based on the model, the bearing's force-displacement relation is examined, and the effects of shaft deformation and external load on the multi-contact tooth mesh load distribution are also analyzed. The advantage of this work is, unlike previous works to search true contact lines through time-consuming iterative strategy, to determine true contact lines between conjugated teeth directly with presentation of deformations of bearings and shafts.

Mesh Editing Using the Motion Feature Vectors (운동 특성 벡터에 기반한 메쉬 에디팅 기법)

  • Lee, Soon-Young;Kim, Chang-Su;Lee, Sang-Uk
    • Journal of Broadcast Engineering
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    • v.13 no.2
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    • pp.214-221
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    • 2008
  • In this paper, we proposed a new mesh editing algorithm based on the motion between two sample meshes. First, the motion vectors are defined as the derivation vector of the corresponding vertices on the sample meshes. Then, the motion feature vectors are extracted between the motion vectors. The motion feature vectors represent the similarity of the vertex motion in a local mesh surface. When a mesh structure is forced by an external motion of anchor vertices, the deformed mesh geometry is obtained by minimizing the cost function with preserving the motion feature vectors. Simulation results demonstrated that the proposed algorithm yields visually pleasing editing results.