Triangle Faces Research Articles

Optimization for 3D Model-based Multi-Camera Deployment

Based on convex optimization techniques, we propose a new multi-camera deployment method for optimal visual coverage of a three-dimensional (3D) object surface. Different from existing methods, the optimal placement of a single camera is formulated as two convex optimization problems, given a set of covered triangle faces. Moreover, this idea is incorporated into a recursive framework to expand the covered area for each camera, wherein initially covered triangle faces are elegantly chosen using an importance criterion for the first recursion. By placing cameras one by one using the same method, the object surface is gradually covered by iteratively removing the covered partition of the previously deployed camera. Due to the usage of convex optimization, each camera is guaranteed to be placed at an optimal pose for a group of triangle faces other than a single one. This merit, together with the importance criterion-based selection of initially covered triangle faces, reduces the number of required cameras while satisfying various constraints including the resolution, field of view, focus and occlusion. Simulation results on two real 3D computer-aided design (CAD) models are presented to verify the effectiveness of the proposed approach.

Fast Surface Construction and NC Milling Based on 3D Scanning

Construction of a rapid surface and processing is an effective way to improve the manufacturing efficiency, this paper linked the 3D scanning, fast surface construction and NC closely, described the whole process of surface data acquisition and processing, surface construction and the process of NC machining. The outer surface of the mouse was scanned from multiple angles by using 3D CaMega scanner, a plurality of point cloud was obtained, the point cloud processing, triangle face processing construct refinement of the model surface and grid lines were all processed in Geomagic Studio software, through adjustments, NURBS surface was generated. Also the mould surface of the mouse was constructed in the UG NX software. This paper wrote the machining process, Programmed NC Milling in UG NX software, generated the trajectory of rough and finishes machining as well as the programs of machining tool. Also CNC milling was processed CNC machining center.

Research of Creating Method for Laser Inner Carving 3D Model Surface Texture Point Cloud

Introduces a kind of method that creating the point cloud for laser inner carving from texture of 3D model surface. At first, the 3D model surface with texture needs to be converted to the triangle faces. Then texture coordinates which corresponded to the vertex will be obtained by visiting the triangle faces. The transform from texture triangle surface to 3D model triangle surface will be completed next. Then the Bayer dithering algorithm should be applied to handle the texture image. At last, the inner carving point cloud will be gained by transforming from the surface texture space to the 3D model space.

Feature Enhancement by Vertex Flow for 3D Shapes

AbstractWe present a new method for enhancing shape features of a mesh surface by moving mesh vertices from low-curvature regions to high-curvature regions or feature regions. The movement of the vertices, also called vertex flow, is driven by minimizing an objective function defined to take into account several important considerations in mesh improvement. First, a new edge-based energy term is used to measure the uniformity of the approximation error of a target shape by a mesh surface. Clearly, given a fixed number of triangle faces of a mesh surface approximating an underlying target surfaces, the approximation is made more uniform by placing more faces are used in higher-curvature regions and fewer faces in lower-curvature regions. Therefore, the minimization of this edge-based energy term provides a strong force to move mesh vertices towards high-curvature regions. Second, to maintain faithful shape approximation during vertex flow, a distance-error term is included to penalize the displacement of m...

Part decomposing algorithm based on STL solid model used in shape deposition manufacturing process

Shape deposition manufacturing is an innovative rapid prototyping technology combining CNC machining and deposition processes and in which if a surface of the part is visible from the build direction it can be directly shaped into desired geometry on part material; if the part features are undercut or face away from the build direction, these part features will be sculptured into the support material in order to form a negative cavity at first, then the part material is deposited into this negative cavity in order to replicate these features into part material. This process is cyclically repeated until all segments have been built. Finally, the sacrificial material is removed, and the finished part is left. This innovative technology has the benefits of commercial rapid prototyping technology; meanwhile, it inherits the accuracy and high surface quality of traditional machining process. For this process to be realized, it is essential to decompose the CAD solid model into a series of manufacturable segments which have no undercut surfaces at the data pretreatment step. In this paper, a solid decomposing strategy is proposed with a detailed discussion on the classification of the segments based on the value of triangle face normal vector, and then an algorithm for auto-decomposing a CAD solid model in STL data format is developed.

Human face shape classification method based on active shape model

To improve the recognition rate and speed on huge face database,automatic face shape classification has attracted more and more attention.Human face shape can be classified into several categories: round face,elliptic face,square face,triangle face,etc.This paper proposed a novel method to classify human face shape automatically based on Active Shape Model(ASM).First,face images of different shapes were trained by ASM to generate different shape models.Then ASM was used to detect the face shape of the test sample,and compared the distance with each face shape model.Finally,nearest-neighbor algorithm was employed to accomplish classification.Experimental results show that the proposed method outperforms the methods based on curvature feature of face contour or feature of chin contour.The method can detect full face shape information,and improve the recognition rate and speed on huge face database.

Isotropic Remeshing with Fast and Exact Computation of Restricted Voronoi Diagram

AbstractWe propose a new isotropic remeshing method, based on Centroidal Voronoi Tessellation (CVT). Constructing CVT requires to repeatedly compute Restricted Voronoi Diagram (RVD), defined as the intersection between a 3D Voronoi diagram and an input mesh surface. Existing methods use some approximations of RVD. In this paper, we introduce an efficient algorithm that computes RVD exactly and robustly. As a consequence, we achieve better remeshing quality than approximation‐based approaches, without sacrificing efficiency. Our method for RVD computation uses a simple procedure and a kd‐tree to quickly identify and compute the intersection of each triangle face with its incident Voronoi cells. Its time complexity is O(mlog n), where n is the number of seed points and m is the number of triangles of the input mesh. Fast convergence of CVT is achieved using a quasi‐Newton method, which proved much faster than Lloyd's iteration. Examples are presented to demonstrate the better quality of remeshing results with our method than with the state‐of‐art approaches.

The Chevrel phase In4.07Mo15S11.87Se7.13with mixed chalcogenide occupancy

The single-crystal of the title compound, indium pentadecamolybdenum nonadeca(sulfide/selenide), was obtained by solid state reaction with an S/Se mixture. It adopts the structure type of In3Mo15Se19 and In3.7Mo15S19, which are non-substituted Chevrel phases in the space group P63/m. The Mo, one S/Se and two In sites have point symmetry m.. and two S/Se and one In atoms are in 3.. sites. This compound contains isolated Mo6 and Mo9 clusters. The shapes of clusters are octa­hedral and confacial biocta­hedral, respectively, face-capped by chalcogen atoms over each triangle face. The Mo—X bonds (X = S, Se) play an important role for the constitution of the framework. The Mo—X distances of 2.479 (2)–2.6687 (9) Å are within the ranges of average values of Mo—S and Mo—Se distances. The In atoms located on sites with m.. symmetry are partially occupied.

수정메이크업을 위한 성인 여성의 얼굴 유형 분석

In this study, photographs of 600 Korean females aged from 20 to 50years old were indirectly measured in Venus face 2D program. The measurements were analyzed by statistical methods. The purpose of this study was to differentiate the facial types of adult women for the beauty industry. As a result of factor analysis, 6 factors were selected the key factors of facial shape: head height(factor 1), head width(factor 2), side face width(factor 3), head width and circumference(factor 4), face length(factor 5), and side face width(factor 6). We categorized facial type into 5 groups with the previous 6 factor. 5 types were most common facial shapes: Oblong face(type 1), Square face(type 2), Oval face(type 3), Round face(type 4), Triangle face(type 5). The results of facial type analysis were showed that Round face(26.6%), Triangle face(25.3%), Oval face(22.3%), Square face(20.0%), Oblong face(5.7%).

Synthesis and structural characterization of dimolybdenum(IV) and molybdenum(VI) complexes with trisbenzenethiolatophosphine ligands

The synthesis and crystal structures of two high valent molybdenum complexes containing trisbenzenethiolatophosphine ligands, [Mo 2(PS3) 2(PS3H)] ( 1) and [Mo(PS3″) 2] ( 2), where PS3 = [P(C 6H 4-2-S) 3] 3−, PS3H = [P(C 6H 4-2-S) 2(C 6H 4-2-SH)] 2−, and PS3″ = [P(C 6H 3-3-Me 3Si-2-S) 3] 3−, are described. Compound 1 is a dimeric Mo(IV) species containing three PS3 ligands with an uncoordinated thiol group. An intramolecular hydrogen bonding S–H⋯S was found in the structure. Two molybdenum ions are bridged by three thiolates. The geometry can be described as two pentagonal bipyramids sharing a triangle face formed by three bridging S atoms. Compound 2 is a Mo(VI) species binding with two tetradentate PS3″ ligands. The eight-coordinate molybdenum center adopts a dodecahedral geometry.

Towards the mechanism of heteroborane isomerisation: 1,2 → 1,2 and 1,2 → 1,7 low-temperature isomerisations from metallations of [5-I-7,8-Ph 2-7,8- nido-C 2B 9H 8] 2−

The reaction between [5-I-7,8-Ph 2-7,8- nido-C 2B 9H 8] 2− and NiCl 2(dppe) affords 1,2-Ph 2-4,4-dppe-12-I-4,1,2- closo-NiC 2B 9H 8 ( 1) and 1,8-Ph 2-2,2-dppe-10-I-2,1,8- closo-NiC 2B 9H 8 ( 2). Reaction between the same carborane ligand and cis-PtCl 2(PMe 2Ph) 2 yields three species, 1,8-Ph 2-2,2-(PMe 2Ph) 2-10-I-2,1,8- closo-PtC 2B 9H 8 ( 3), 1,8-Ph 2-2,2-(PMe 2Ph) 2-12-I-2,1,8- closo-PtC 2B 9H 8 ( 4), and 1,8-Ph 2-2,2-(PMe 2Ph) 2-7-I-2,1,8- closo-PtC 2B 9H 8 ( 5). Compounds 1– 5 have been characterised spectroscopically and crystallographically. The 4,1,2-MC 2B 9 architecture of 1 constitutes a “1,2 → 1,2” cage C atom isomerisation, and the 2,1,8-MC 2B 9 architectures of 2– 5 a 1,2 → 1,7 cage C atom isomerisation, relative to the presumed first product of the metallations, 1,2-Ph 2-3,3-L 2-9-I-3,1,2- closo-MC 2B 9H 8 [M = Ni, L 2 = dppe; M = Pt, L 2 = (PMe 2Ph) 2]. The location of the (iodide) labelled boron vertex in the products allows speculation as to the mechanism of these isomerisations and the possible involvement of triangle face rotation is discussed.

Nickelation of [3‐Et‐7,8‐Ph2‐7,8‐nido‐C2B9H8]2−: synthesis and characterization of 1,2 → 1,2 and 1,2 → 1,7 isomerized products

AbstractThe reaction between [3‐Et‐7,8‐Ph2‐7,8‐nido‐C2B9H8]2− and Ni(dppe)Cl2 in tetrahydrofuran affords major and minor products, identified spectroscopically and crystallographically. The major species is 1,2‐Ph2‐4‐dppe‐6‐Et‐4,1,2‐closo‐NiC2B9H8, which arises from the presumed initial product 1,2‐Ph2‐3‐dppe‐6‐Et‐3,1,2‐closo‐NiC2B9H8 by a sterically induced 1,2 → 1,2 C atom isomerization, typical of overcrowded nickelacarboranes. The minor species is 1,8‐Ph2‐2‐dppe‐4‐Et‐2,1,8‐closo‐NiC2B9H8, arising from an unexpected 1,2 → 1,7 carbon‐atom isomerization of the initial product. The fact that one boron atom is labelled with an Et group, coupled with the fact that these isomerizations occur at low temperatures, allows comment on the isomerization mechanisms. The minor isomer cannot be explained by reference to Wales' sequential diamond–square–diamond mechanism for 1,2‐closo‐C2B10H12 → 1,7‐closo‐C2B10H12. A simple rationalization of the formation of both major and minor isomers is available through triangle face rotation. Copyright © 2003 John Wiley & Sons, Ltd.

面情報を用いた形状簡略化に関する一考察

In recent years, three-dimensional objects have been utilized as internet media contents because computer hardware has high capability and its software cost decreases. In general, the three-dimensional objects are called polygon models that consist of a group of triangle meshes and they can be drawn at high speed by high quality CPU and 3D graphics accelerator mesh simplification have been proposed of late years. In the former methods, polygon models are simplified by using only edge information. On the other hand, the proposed method simplifies the model using triangle edge and face information. Experimental results show that the method is effective for preserving the feature of the polygon model.

Molecular Crystal Structure and Electron Density Distribution in the Crystal of Pentaethyl-1,5-dicarba-closo-pentaborane [C2B3(Et)5] at 120 K

The molecular and crystal structure and electron density distribution were studied for a single crystal of pentaethyl-1,5-dicarba-closo-pentaborane C2B3(Et)5 by the high-resolution X-ray diffraction method at 120 K (5696 observed reflections, R = 0.056). The single crystal was grown by in situ crystallization with an IR-laser beam producing a molten zone in a Lindeman capillary. In crystal the molecule of the title compound has local C1-symmetry with different orientations of the Et-groups with respect to the central trigonal-bipyramidal C2B3 fragment, mean B−C and B−B distances are 1.571 and 1.876 Å, respectively, the axial C...C distance is 2.277 Å. An ab initio calculations of the molecular structure indicated that rotation barriers of the Et groups with respect to the central frame are very small, that may be the reason of the low molecular symmetry and diffrerent orientation of the Et groups in molecule due to the crystal packing effects. Deformation electron density (DED) maps obtained via a conventional “X−X” method, and using a multipole refinement procedure, showed charge accumulation in the B−C bonds of the central frame, and these bonds were found to be essentially bent outward of the C2B3 cage. On the contrary, no charge accumulation was detected in the B−B bonds, thus indicating the absence of the direct B−B interactions. Positive and delocalized DED was also found in all B−C−B triangle faces of the central cage, that indicates the contribution of the multicenter bonding in the electronic structure of this formally electron-precise molecule. Topological analysis of the experimental charge density distribution has been performed including an analysis of the Laplacian maps, and these data confirmed all important features of the DED maps.