Shiyao Jin

A survey of methods for moving least squares surfaces

Moving least squares (MLS) surfaces representation directly defines smooth surfaces from point cloud data, on which the differential geometric properties of point set can be conveniently estimated. Nowadays, the MLS surfaces have been widely applied in the processing and rendering of point-sampled models and increasingly adopted as the standard definition of point set surfaces. We classify the MLS surface algorithms into two types: projection MLS surfaces and implicit MLS surfaces, according to employing a stationary projection or a scalar field in their definitions. Then, the properties and constrains of the MLS surfaces are analyzed. After presenting its applications, we summarize the MLS surfaces definitions in a generic form and give the outlook of the future work at last.

Non-rigid Registration in 3D Implicit Vector Space

We present an implicit approach for pair-wise non-rigid registration of moving and deforming objects. Shapes of interest are implicitly embedded in the 3D implicit vector space. In this implicit embedding space, registration is performed using a global-to-local framework. Firstly, a non-linear optimization functional defined on the vector distance function is used to find the global alignment between shapes. Secondly, an incremental cubic B-spline free form deformation is used to recover the non-rigid transformation parameters. Local non-rigid registration is posed in terms of minimising an energy functional, for which we give a closed-form linear system and solve it using an improved iterative Gauss-Seidel method. Our approach can consistently produce smooth and continuous registration fields, and correctly establish dense one-to-one correspondences. It can naturally deal with both open partial and closed shapes, and imperfect models with gaps and noise, through its use of the implicit vector representation. Experimental results on several datasets demonstrate the robustness of the proposed method.

A Data-Driven Approach to Efficient Character Articulation

In this paper, we propose a data-driven approach for realistic deformation of articulated meshes: the wide availability of pose data makes such an approach feasible. We use multiple reference models, combined with a fast linear blending skinning (LBS) method in local spaces. By exploiting information from the reference models, realistic deformation is achieved, yet with computational efficiency comparable to traditional blending methods-our approach is suitable for real-time applications. We demonstrate the effectiveness of our algorithm using various examples.

Color-aware surface registration

Shape registration is fundamental to 3D object acquisition; it is used to fuse scans from multiple views. Existing algorithms mainly utilize geometric information to determine alignment, but this typically results in noticeable misalignment of textures (i.e. surface colors) when using RGB-depth cameras. We address this problem using a novel approach to color-aware registration, which takes both color and geometry into consideration simultaneously. Color information is exploited throughout the pipeline to provide more effective sampling, correspondence and alignment, in particular for surfaces with detailed textures. Our method can furthermore tackle both rigid and non-rigid registration problems (arising, for example, due to small changes in the object during scanning, or camera distortions). We demonstrate that our approach produces significantly better results than previous methods. Graphical abstractUsing rigid and non-rigid registration to correct misalignments in geometry and texture. Two input textured surfaces (a) are captured by RGB-D cameras; the camera configuration provides initial alignment (b). Successive rigid (c) and non-rigid (d) steps improve it, giving a final surface with high-quality texturesDisplay Omitted HighlightsUsing color and geometric to źnd correspondences in both rigid and non-rigid cases.Using color when determining the transformation/deformation in aligning surfaces.Proving our algorithms effectiveness when aligning richly textured surfaces.

A mesh meaningful segmentation algorithm using Skeleton and minima-rule

In this paper, a hierarchical shape decomposition algorithm is proposed, which integrates the advantages of skeleton-based and minima-rule-based meaningful segmentation algorithms. The method makes use of new geometrical and topological functions of skeleton to define initial cutting critical points, and then employs salient contours with negative minimal principal curvature values to determine natural final boundary curves among parts. And sufficient experiments have been carried out on many meshes, and shown that our framework can provide more reasonable perceptual results than single skeleton-based [8] or minima-rule-based [15] algorithm. In addition, our algorithm not only can divide a mesh of any genus into a collection of genus zero, but also partition level-of-detail meshes into similar parts.

Dynamic fault tolerance in distributed simulation system

Distributed simulation system is widely used for forecasting, decision-making and scientific computing. Multi-agent and Grid have been used as platform for simulation. In order to survive from software or hardware failures and guarantee successful rate during agent migrating, system must solve the fault tolerance problem. Classic fault tolerance technology like checkpoint and redundancy can be used for distributed simulation system, but is not efficient. We present a novel fault tolerance protocol which combines the causal message logging method and prime-backup technology. The proposed protocol uses iterative backup location scheme and adaptive update interval to reduce overhead and balance the cost of fault tolerance and recovery time. The protocol has characteristics of no orphan state, and do not need the survival agents to rollback. Most important is that the recovery scheme can tolerant concurrently failures, even the permanent failure of single node. Correctness of the protocol is proved and experiments show the protocol is efficient.

A service-oriented architecture for tele-immersion

Sharing virtual environments with the remote collaborators as well as the topic of the collaboration may be better than collaborating with them in person. In this paper we will discuss our ongoing work to enable effective collaboration between remote participants within tele-immersion based on Web service implemented by Microsoft Visual Studio .Net. We will discuss the architecture of the tele-immersion system created, the implemented methodology, the technology driving our current research, and the lessons learned. Our focus is on the service-oriented architecture taking of the Web service and COM+ technology.

An Error-Resilient Arithmetic Coding Algorithm for Compressed Meshes

The effort of on-the-fly accessing 3D contents over the Internet has been done in recent years. And 3D streaming has been investigated to represent 3D models in the compact format and progressively transmit them on the limited-bandwidth and lossy channel. In the paper, an error resilient 3D mesh coding algorithm is presented, which employs an extended multiple quantization (EMQ) arithmetic coder method, inspired by the error-resilient JPEG 2000 image coding standards. With periodic arithmetic coder restarting and termination markers, the error resilient EMQ coder divides bit stream into little independent parts and enables basic transmission error containment. Furthermore, the EMQ coder has the intrinsic capacity of handling noise by using the maximum a posteriori (MAP) decoder. Experiments show that the method improves the mesh transmission quality in a simulated network environment.

A Meaningful Mesh Segmentation Based on Local Self-similarity Analysis

On the basis of minima rule from the cognitive theory, this paper presents an algorithm decomposing a mesh into smaller parts by feature contours, gotten from the minima negative curvature vertices. The algorithm is carried out in two steps. Firstly, to avoid over-segmentation, our method excludes unimportant local adjacent similar contours. Secondly, the remnant salient contours are automatically completed to form short loops around meshs parts, constrained by two near parallel cutting planes that are determined by principal component analysis of all vertices. The algorithm has been demonstrated on many meshes, and the results show that it not only can perceptual group the adjacent self-similarity regions, but also can achieve reasonable segmentations.

A service-oriented architecture for progressive delivery and adaptive rendering of 3d content

Content adaptation techniques for progressive delivery of 3D models to clients with different rendering capabilities and network connections has been extensively studied in recent years. In this paper, a client-server based novel service-oriented architecture for 3D content delivery and adaptive rendering is presented. The architecture is integrated into the service-oriented architecture (SOA) framework, and it is designed to enhance the client user experience by progressively delivering 3D content stream quickly, reliably, and with high quality based on the adaptive requirements. At the client end the stream is progressively decoded up to the “best” level-of-details as defined by the client computational resources and the user inclination.