• ETRI Journal
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• v.32 no.1
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• pp.163-165
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• 2010

A trend in 3D mesh compression is codec design with low computational complexity which preserves the input vertex and face order. However, this added information increases the complexity. We present a fast 3D mesh compression method that compresses the redundant shared vertex information between neighboring faces using simple first-order differential coding followed by fast entropy coding with a fixed length prefix. Our algorithm is feasible for low complexity designs and maintains the order, which is now part of the MPEG-4 scalable complexity 3D mesh compression standard. The proposed algorithm is 30 times faster than MPEG-4 3D mesh coding extension.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.07a
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• pp.282-285
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• 2020

포인트 클라우드는 2D 이미지를 3D 로 복원하고 표현하는 방법으로써 많은 연구가 진행되고 있다. 하지만 포인트 클라우드로만 표현할 경우 포인트와 포인트 사이에 빈 공간이 존재하여 실제 3D 물체와 차이가 존재한다. Mesh Reconstruction 은 보다 실제 3D 물체처럼 보이기 위해 포인트와 포인트를 이어 mesh 를 생성하는 방법인데 생성된 mesh 의 quality 는 texturing 을 거친 최종 결과에 큰 영향을 끼친다. 기존에 존재하는 이미지를 기반으로 생성된 포인트 클라우드의 Mesh Reconstruction 방법은 노이즈에 어느 정도 강한 면을 보이지만 최종 결과에서 잘 이어진 mesh 를 생성하지 못하고 hole 이 존재하는 문제가 있다. 본 논문에선 노이즈에 강하면서 최종 결과에서 잘 이어진 mesh 를 만들 수 있도록 하는 Mesh Reconstruction 알고리즘을 제안한다.

• Journal of IKEEE
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• v.26 no.2
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• pp.160-168
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• 2022

In this paper, we propose a 3D mesh reconstruction method from a single image using deep learning and a sphere shape transformation method. The proposed method has the following originality that is different from the existing method. First, the position of the vertex of the sphere is modified to be very similar to the 3D point cloud of an object through a deep learning network, unlike the existing method of building edges or faces by connecting nearby points. Because 3D point cloud is used, less memory is required and faster operation is possible because only addition operation is performed between offset value at the vertices of the sphere. Second, the 3D mesh is reconstructed by covering the surface information of the sphere on the modified vertices. Even when the distance between the points of the 3D point cloud created by correcting the position of the vertices of the sphere is not constant, it already has the face information of the sphere called face information of the sphere, which indicates whether the points are connected or not, thereby preventing simplification or loss of expression. can do. In order to evaluate the objective reliability of the proposed method, the experiment was conducted in the same way as in the comparative papers using the ShapeNet dataset, which is an open standard dataset. As a result, the IoU value of the method proposed in this paper was 0.581, and the chamfer distance value was It was calculated as 0.212. The higher the IoU value and the lower the chamfer distance value, the better the results. Therefore, the efficiency of the 3D mesh reconstruction was demonstrated compared to the methods published in other papers.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.11
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• pp.4463-4482
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• 2020

Mesh model generated from 3D reconstruction usually comes with lots of noise, which challenges the performance and robustness of mesh simplification approaches. To overcome this problem, we present a novel method for mesh simplification which could preserve structure and improve the accuracy. Our algorithm considers both the planar structures and linear features. In the preprocessing step, it automatically detects a set of planar structures through an iterative diffusion approach based on Region Seed Growing algorithm; then robust linear features of the mesh model are extracted by exploiting image information and planar structures jointly; finally we simplify the mesh model with plane constraint QEM and linear feature preserving strategies. The proposed method can overcome the known problem that current simplification methods usually degrade the structural characteristics, especially when the decimation is extreme. Our experimental results demonstrate that the proposed method, compared to other simplification algorithms, can effectively improve the quality of mesh and yield an increased robustness on noisy input mesh.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.79-82
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• 2004

In this study, a new refinement technique for 3-dimensional hexahedral element mesh is proposed, which is aimed at the control of mesh density. With the proposed scheme the mesh is refined adaptively to the elemental error which is estimated by 'a posteriori' error estimator based on the energy norm. A desired accuracy of an analysis i.e. a limit of error defines the new desired mesh density map on the current mesh. To obtain the desired mesh density, the refinement procedure is repeated iteratively until no more elements to be refined exist. In the algorithm, at first the regions of mesh to be refined are defined and, then, the zero-thickness element layers are inserted into the interfaces between the regions. All the meshes in the regions, in which the zero-thickness layers are inserted, are to be regularized in order to improve the shape of the slender elements on the interfaces. This algorithm is tested on a simple shape of 2-d quadrilateral element mesh and 3-d hexahedral element mesh. A numerical example of elastic deformation of a plate with a hole shows the effectiveness of the proposed refinement scheme.

• Korean Journal of Computational Design and Engineering
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• v.10 no.3
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• pp.162-167
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• 2005

A 3D solid element mesh generation algorithm was newly developed. 3D surface points of global rectangular coordinates were supplied by a 3D laser scanner. The algorithm is strait forward and simple but it generates hexahedral solid elements. Then, the surface rectangular elements were generated from the solid elements. The key of the algorithm is elimination of unnecessary elements and 3D boundary surface fitting using given 3D surface point data.

• Journal of Korea Multimedia Society
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• v.7 no.1
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• pp.80-90
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• 2004

Watermarking algorithm for 3D mesh model using EGI distribution of each patch is proposed. The proposed algorithm divides a 3D mesh model into 6 patches to have the robustness against the partial geometric deformation. Plus, it uses EGI distributions as the consistent factor that has the robustness against the topological deformation. To satisfy both geometric and topological deformation, the same watermark bits for each subdivided patch are embedded by changing the mesh normal vectors. Moreover, the proposed algorithm does not need not only the original mesh model but also the resampling process to extract the watermark. Experimental results verify that the proposed algorithm is imperceptible and robust against geometrical and topological attacks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.11C
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• pp.1592-1599
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• 2004

In this paper, we proposed the 3D mesh watermarking using projection onto convex sets (POCS). 3D mesh is projected iteratively onto two constraint convex sets until it satisfy the convergence condition. These sets consist of the robustness set and the invisibility set that designed to embed watermark Watermark is extracted without original mesh by using the decision values and the index that watermark is embedded. Experimental results verified that the watermarked mesh have the robustness against mesh simplification, cropping, affine transformation, and vertex randomization as well as the invisibility.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.6
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• pp.132-140
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• 2003

In this paper, we propose a new scheme for view-dependent transmission of three-dimensional (3-D) polygonal mesh models with hierarchial partitioning. In order to make a view-dependent representation of 3-D mesh models, we combine sequential and progressive mesh transmission techniques. By setting higher priorities to visible parts than invisible parts, we can obtain good qualify of 3-D models in a limited transmission bandwidth. In this paper, we use a multi -layer representation of 3-D mesh models based on hierarchical partitioning. After representing the 3-D mesh model in a hierarchical tree, we determine resolutions of partitioned submeshes in the last level. Then, we send 3-D model data by view-dependent selection using mesh merging and mesh splitting operations. By the partitioned mesh merging operation, we can reduce the joint boundary information coded redundantly in the partitioned submeshes. We may transmit additional mesh information adaptively through the mesh spritting operation.

• Journal of Korea Multimedia Society
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• v.19 no.8
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• pp.1619-1625
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• 2016

Recently, as the public interests about the 3D printing technology are increased, various kinds of 3D printers are being released. But, they are limited to use because they cannot fabricate an object which is larger than the printer's printing volume. To relieve this problem, we propose an interactive 3D mesh editing system for 3D printing the object that is larger than the printing volume. The proposed 3D editing system divides the input 3D mesh using the user's line drawings defining cutting planes and it attaches various connectors. The output meshes are guaranteed to fabricate without post-processing. The printed parts can be assembled using the connectors. Our proposed system has an advantage that it can be used easily by non-professional 3D printer users.