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3D Models Simplification Algorithm for Mobile Devices
Abstract
As we know, the mobile device screen is small. The lower accuracy of the model is relatively weak and the capacity to handle high detailed model is very limited. What's more, the existing three-dimensional simplification algorithms are for the personal computer and they are not suitable for the mobile terminals. Thus, we propose a novel 3D model simplification algorithm based on feature points. We will find the model surface curvature of each vertex, based on the model feature points. For these points, we present a new method to obtain it. Experimental results show that the algorithm can accurately reflect the model changes of the local surface geometry, and effectively keep the details of the model characteristics.
... them with others. Mobile devices (smartphones, tables) are natural tools for this kind of presentation, but many new challenges has to be overcome, mainly related with its limited computational power and transmission channel [7,12,19]. ...
... Thinking about mobile devices connected with mobile network, we should take care of the bandwidth consumed by the visualization system. This topic is usually studied for games or augmented reality applications [12,19]. Smooth displaying of realistic 3D worlds on thin, mobile clients requires special techniques (mesh streaming, compressed meshes, server rendering). ...
The article presents software module designed for efficient and convenient visualization of 3D models inside the web browser environment. It is written purely in JavaScript and takes advantages of the new HTML 5 standard. The authors focus on mobile devices, so special attention is given on efficiency and low network usage. Proposed solution based on progressive mesh streaming is compared with server side rendering approach. The results of usability tests performed on real-life random users group will be discussed.
We present a versatile and complete free-form shape modeling framework for point-sampled geometry. By combining unstructured point clouds with the implicit surface definition of the moving least squares approximation, we obtain a hybrid geometry representation that allows us to exploit the advantages of implicit and parametric surface models. Based on this representation we introduce a shape modeling system that enables the designer to perform large constrained deformations as well as boolean operations on arbitrarily shaped objects. Due to minimum consistency requirements, point-sampled surfaces can easily be re-structured on the fly to support extreme geometric deformations during interactive editing. In addition, we show that strict topology control is possible and sharp features can be generated and preserved on point-sampled objects. We demonstrate the effectiveness of our system on a large set of input models, including noisy range scans, irregular point clouds, and sparsely as well as densely sampled models. © 2003 ACM.
This paper presents a new tool, Metro, designed to compensate for a deficiency in many simplification methods proposed in literature. Metro allows one to compare the difference between a pair of surfaces (e.g. a triangulated mesh and its simplified representation) by adopting a surface sampling approach. It has been designed as a highly general tool, and it does no assumption on the particular approach used to build the simplified representation. It returns both numerical results (meshes areas and volumes, maximum and mean error, etc.) and visual results, by coloring the input surface according to the approximation error.
This paper presents a practical technique to automatically compute approximations of polygonal representations of 3D objects. It is based on a previously developed model simplification technique which applies vertex-clustering. Major advantages of the vertex-clustering technique are its low computational cost and high data reduction rate, and thus suitable for use in interactive applications. This paper advances the technique with careful consideration of approximation quality and smoothness in transitions between different levels of simplification, while maintaining its efficiency and effectiveness. Its major contributions include: accuracy in grading vertices for indication of their visual importance, robustness in clustering for better preservation of important features and consistencies between levels of simplification, thick-lines with dynamic normals to maximize visual fidelity, and exploitation of object and image space relationship for levels-of-simplification determination. CR Categories and Subject Descriptors: I.3.5 (Computer
We present a method for end-to-end out-of-core simplification and view-dependent visualization of large surfaces. The method consists of three phases: (1) memory insensitive simplification; (2) memory insensitive construction of a multiresolution hierarchy; and (3) run-time, output-sensitive, view-dependent rendering and navigation of the mesh. The first two off-line phases are performed entirely on disk, and use only a small, constant amount of memory, whereas the run-time system pages in only the rendered parts of the mesh in a cache coherent manner. As a result, we are able to process and visualize arbitrarily large meshes given a sufficient amount of disk space; a constant multiple of the size of the input mesh.Similar to recent work on out-of-core simplification, our memory insensitive method uses vertex clustering on a rectilinear octree grid to coarsen and create a hierarchy for the mesh, and a quadric error metric to choose vertex positions at all levels of resolution. We show how the quadric information can be used to concisely represent vertex position, surface normal, error, and curvature information for anisotropic view-dependent coarsening and silhouette preservation.The run-time component of our system uses asynchronous rendering and view-dependent refinement driven by screen-space error and visibility. The system exploits frame-to-frame coherence and has been designed to allow preemptive refinement at the granularity of individual vertices to support refinement on a time budget.Our results indicate a significant improvement in processing speed over previous methods for out-of-core multiresolution surface construction. Meanwhile, all phases of the method are disk and memory efficient, and are fairly straightforward to implement.
In this paper we introduce a new compressed representation for the connectivity of a triangle mesh. We present local compression and decompression algorithms which are fast enough for real time applications. The achieved space compression rates keep pace with the best rates reported for any known global compression algorithm. These nice properties have great benefits for several important applications. Naturally, the technique can be used to compress triangle meshes without significant delay before they are stored on external devices or transmitted over a network. The presented decompression algorithm is very simple allowing a possible hardware realization of the decompression algorithm which could significantly increase the rendering speed of pipelined graphics hardware. CR Categories: I.3.1 [Computer Graphics]: Hardware Architecture; I.3.3 [Computer Graphics]: Picture/Image Generation--- Display algorithms Keywords: Mesh Compression, Algorithms, 3D Graphics Hardware, Graphics 1 In...
A new interpolatory subdivision scheme for surface design is presented. The new scheme is designed for a general triangulation of control points and has a tension parameter that provides design flexibility. The resulting limit surface is C1 for a specified range of the tension parameter, with a few exceptions. Application of the butterfly scheme and the role of the tension parameter are demonstrated by several examples.
This paper describes a new method to extract feature lines directly from a surface point cloud. No surface reconstruction is needed in advance, only the inexpensive computation of a neighbor graph connecting nearby points.
We present a framework and algorithms for multiresolution modeling of point-sampled geometry. Most of our techniques extend the key ingredients of recent multiresolution editing concepts, including geometry smoothing, simplification, and offset computation, to point clouds. Using these building blocks, we designed a powerful and versatile hierarchical representation for point-based modeling. An intuitive editing metaphor along with dynamic resampling techniques facilitates modeling operations at diftbrent scales and enables us to effectively handle very large model deformations. In our approach all processing is performed directly on point-sampled geometry without the need for intermediate local triangulation or meshing.
Many applications in computer graphics require complex, highly detailed models. However, the level of detail actually necessary may vary considerably. To control processing time, it is often desirable to use approximations in place of excessively detailed models. We have developed a surface simplification algorithm which can rapidly produce high quality approximations of polygonal models. The algorithm uses iterative contractions of vertex pairs to simplify models and maintains surface error approximations using quadric matrices. By contracting arbitrary vertex pairs (not just edges), our algorithm is able to join unconnected regions of models. This can facilitate much better approximations, both visually and with respect to geometric error. In order to allow topological joining, our system also supports non-manifold surface models. CR Categories: I.3.5 [Computer Graphics]: Computational Geometry and Object Modeling---surface and object representations Keywords: surface simplificatio...
We describe an adaptive display algorithm for interactive frame rates during visualization of very complex virtual environments. The algorithm relies upon a hierarchical model representation in which objects are described at multiple levels of detail and can be drawn with various rendering algorithms. The idea behind the algorithm is to adjust image quality adaptively to maintain a uniform, user-specified target frame rate. We perform a constrained optimization to choose a level of detail and rendering algorithm for each potentially visible object in order to generate the "best" image possible within the target frame time. Tests show that the algorithm generates more uniform frame rates than other previously described detail elision algorithms with little noticeable difference in image quality during visualization of complex models. CR Categories and Subject Descriptors: [Computer Graphics]: I.3.3 Picture/Image Generation -- viewing algorithms; I.3.5 Computational Geometry and Objec...
The progressive mesh representation is in general introduced for a continuous level of detail, and with it smooth transition between meshes can be achieved. However, the method is impractical for realtime simplification. Despite that, the realtime generation of progressive meshes is often required for applications such as in a robot simulation system or a flight simulation system where models are constantly modified by the actions of object collision, object destruction and reconstruction, etc. A new method is presented in this paper to tackle realtime simplification through progressive meshes. By the algorithm only the current mesh and readily accessible local information of each vertex, such as vertex position, edge length, neighboring vertices, adjacent faces, and face normals, are considered at each simplification step. All edge-collapse costs are calculated and sorted into a binary tree using the heap sort algorithm at the initial stage. At the iterative stages only the neighboring affected costs need be recalculated and rearranged in the binary tree. Other properties, such as vertex color and face texture, are processed in the same way as the geometry. The algorithm greatly improves the time performance under the constraint that the quality of the generated meshes be acceptable. Tests show that the algorithm is viable in a realtime simplification for medium-scale virtual models on PC platforms.
This paper describes a method for recursively generating surfaces that approximate points lying-on a mesh of arbitrary topology. The method is presented as a generalization of a recursive bicubic B-spline patch subdivision algorithm. For rectangular control-point meshes, the method generates a standard B-spline surface. For non-rectangular meshes, it generates surfaces that are shown to reduce to a standard B-spline surface except at a small number of points, called extraordinary points. Therefore, everywhere except at these points the surface is continuous in tangent and curvature. At the extraordinary points, the pictures of the surface indicate that the surface is at least continuous in tangent, but no proof of continuity is given. A similar algorithm for biquadratic B-splines is also presented.
Presents an algorithm for performing view-dependent simplifications of a triangulated polygonal model in real-time. The simplifications are dependent on viewing direction, lighting and visibility, and are performed by taking advantage of image-space, object-space and frame-to-frame coherences. A continuous level-of-detail representation for an object is first constructed off-line. This representation is then used at run-time to guide the selection of appropriate triangles for display. The list of displayed triangles is updated incrementally from one frame to the next. Our approach is more effective than the current level-of-detail-based rendering approaches for most scientific visualization applications where there are a limited number of highly complex objects that stay relatively close to the viewer.
The behaviour of the limits surface defined by a recursive division construction can be analysed in terms of the eigenvalues of a set of matrices. This analysis predicts effects actually observed, and leads to suggestions for the further improvement of the method.
In this paper we describe and analyze a method based on local least square fitting for estimating the normals at all sample points of a point cloud data (PCD) set, in the presence of noise. We study the effects of neighborhood size, curvature, sampling density, and noise on the normal estimation when the PCD is sampled from a smooth curve in R2 or a smooth surface in R3 and noise is added. The analysis allows us to find the optimal neighborhood size using other local information from the PCD. Experimental results are also provided.
This paper introduces the concept of Geometry Compression, al- lowing 3D triangle data to be represented with a factor of 6 to 10 times fewer bits than conventional techniques, with only slight loss- es in object quality. The technique is amenable to rapid decompres- sion in both software and hardware implementations; if 3D render- ing hardware contains a geometry decompression unit, application geometry can be stored in memory in compressed format. Geome- try is first represented as a generalized triangle mesh, a data struc- ture that allows each instance of a vertex in a linear stream to spec- ify an average of two triangles. Then a variable length compression is applied to individual positions, colors, and normals. Delta com- pression followed by a modified Huffman compression is used for positions and colors; a novel table-based approach is used for nor- mals. The table allows any useful normal to be represented by an 18-bit index, many normals can be represented with index deltas of 8 bits or less. Geometry compression is a general space-time trade- off, and offers advantages at every level of the memory/intercon- nect hierarchy: less storage space is needed on disk, less transmis- sion time is needed on networks.
Triangle mesh simplification is of great interest in a variety of knowledge domains, since it allows manipulation and visualization of large models, and it is the starting point for the design of many multiresolution representations. A crucial point in the structure of a simplification method is the definition of an appropriate metric for guiding the decimation process, with the purpose of generating low error approximations at different levels of resolution. This paper proposes two new alternative metrics for mesh simplification, with the aim of producing high-quality results with reduced execution time and memory usage, and being simple to implement. A set of different established metrics is also described and a comparative evaluation of these metrics against the two new metrics is performed. A single implementation is used in the experiments, in order to enable the evaluation of these metrics independently from other simplification aspects. Results obtained from the simplification of a number of models, using the different metrics, are compared.
In earlier work, we introduced the progressive mesh (PM) represen- tation, a new format for storing and transmitting arbitrary triangle meshes. For a given mesh, the PM representation defines a con- tinuous sequence of level-of-detail approximations, allows smooth visual transitions (geomorphs) between these approximations, sup- ports progressive transmission, and makes an effective compression scheme. In this paper, we present data structures and algorithms for efficient implementation of the PM representation and its ap- plications. Also, we report quantitative results using a variety of computer graphics models.
To provide high quality of service (QoS) for delay sensitive real-time traffic in wireless local area network-based (WLAN) mesh networks is a challenging task. In particular for real-time flows subject to multiple hops, mobility and time-varying channel, the performance of real-time flows will be degraded greatly. Efficient allocation and management of resources, such as transmission rate and throughput, is a crucial element and an attractive and efficient way for interconnecting access points (APs) to form an efficient multihop WLAN mesh network supporting QoS. Considering that IEEE 802.11 WLAN physical layers (PHYs) provide multiple transmission rates by employing different modulations and channel coding schemes, it is an important issue how to select the transmission rate so that the performance is improved, since each link generally has different characteristics with other links. In order to support real-time traffic, an efficient intelligent rate control algorithm is proposed in this paper, which aims to improve the system performance by adaptively adjusting the transmission rate to the current channel status. Based on the learning the local information of each node, the proposed algorithm can achieve accurate channel estimation without any extra implementation effort and modifications to the current 802.11 standard. And each node is able to select the optimized transmission rate, so that the system performance can be improved obviously. The proposed scheme also offers an appealing combination of the allocation of transmission rate and the current link condition. Based on the basic relationship between them, the intelligent rate control algorithm maximizes the throughput with periodic learning of channel variation and system status. Theoretical analysis proves that the proposed algorithm is quickly convergent. Detailed simulation and numerical results show the proposed rate control algorithm closely approximates the ideal case with the perfect knowledge about the channel. Compared with the existed schemes, the proposed algorithm can also significantly improve the system performance in terms of packet loss rate, end-to-end delay and throughput.
We present a new multiphase method for efficiently simplifying polygonal surface models of arbitrary size. It operates by combining an initial out-of-core uniform clustering phase with a subsequent in-core iterative edge contraction phase. These two phases are both driven by quadric error metrics, and quadrics are used to pass information about the original surface between phases. The result is a method that produces approximations of a quality comparable to quadric-based iterative edge contraction, but at a fraction of the cost in terms of running time and memory consumption.
The key to real-time rendering of large-scale surfaces is to locally adapt surface geometric complexity to changing view parameters. Several schemes have been developed to address this problem of view-dependent level-of-detail control. Among these, the view-dependent progressive mesh (VDPM) framework represents an arbitrary triangle mesh as a hierarchy of geometrically optimized refinement transformations, from which accurate approximating meshes can be efficiently retrieved. In this paper we extend the general VDPM framework to provide temporal coherence through the run-time creation of geomorphs. These geomorphs eliminate "popping" artifacts by smoothly interpolating geometry. Their implementation requires new output-sensitive data structures, which have the added benefit of reducing memory use. We specialize the VDPM framework to the important case of terrain rendering. To handle huge terrain grids, we introduce a block-based simplification scheme that constructs a progressive mesh as a hierarchy of block refinements. We demonstrate the need for an accurate approximation metric during simplification. Our contributions are highlighted in a real-time flyover of a large, rugged terrain. Notably, the use of geomorphs results in visually smooth rendering even at 72 frames/sec on a graphics workstation.
We present an algorithm for performing view-dependent simplifications of a triangulated polygonal model in real-time. The simplifications are dependent on viewing direction, lighting, and visibility and are performed by taking advantage of image-space, objectspace, and frame-to-frame coherences. A continuous level-of-detail representation for an object is first constructed off-line. This representation is then used at run-time to guide the selection of appropriate triangles for display. The list of displayed triangles is updated incrementally from one frame to the next. Our approach is more effective than the current level-of-detail-based rendering approaches for most scientific visualization applications where there are a limited number of highly complex objects that stay relatively close to the viewer.
While many effective automatic surface simplification algorithms have been developed, they often produce poor approximations when a model is simplified to a very low level of detail. Furthermore, previous algorithms are not sensitive to semantic or highlevel meanings of models. In this paper, we present a user-guided approach for mesh simplification that aims to overcome such limitations. Our proposed method allows users to selectively control the relative importance of different surface regions and preserve various features through the imposition of geometric constraints. Using our system, users can produce perceptually improved approximations with very little effort.
The decimation of highly detailed meshes has emerged as an important issue in many computer graphics related fields. A whole library of different algorithms has been proposed in the literature. By carefully investigating such algorithms, we can derive a generic structure for mesh reduction schemes which is analogous to a class of greedy-algorithms for heuristic optimization. Particular instances of this algorithmic template allow to adapt to specific target applications. We present a new mesh reduction algorithm which clearly reflects this meta scheme and efficiently generates decimated high quality meshes while observing global error bounds. Introduction In several areas of computer graphics and geometric modeling, the representation of surface geometry by polygonal meshes is a well established standard. However, the complexity of the object models has increased much faster than the through-put of today's graphics hardware. Hence, in order to be able to display and modify geometric ...
The recent growth in the size and availability of large triangular surface models has generated interest in compact multi-resolution progressive representation and data transmission. An ongoing challenge is to design an efficient data structure that encompasses both compactness of geometric representations and visual quality of progressive representations. In this paper we introduce a topological layering based data-structure and an encoding scheme to build a compact progressive representation of an arbitrary triangular mesh (a 2D simplicial complex in 3D) with attached attribute data. This compact representation is composed of multiple levels of detail that can be progressively transmitted and displayed. The global topology, which is the number of holes and connected components, can be flexibly changed among successive levels while still achieving guaranteed size of the coarsest level mesh for very complex models. The flexibility in our encoding scheme also allows topology preserving progressivity.
In this paper we present a mesh compression method based on a multiresolution decomposition whose detail coefficients have a compact representation and thus smaller entropy than the original mesh. Given an arbitrary triangular mesh with an irregular connectivity, we use a hierarchical simplification scheme, which generates a multiresolution model. By reversing the process we define a hierarchical progressive refinement process, where a simple prediction plus a correction is used for inserting vertices to form a finer level. We show how the connectivity of an arbitrary triangulation can be encoded efficiently by a coloring technique, and recovered incrementally during the progressive reconstruction of the original mesh. Keywords: compression, streaming, progressive meshes, simplification 1 Introduction The most common representation of 3D geometric models is triangular meshes. Although they have had prominent representation in computer graphics for a long time, only recently has more ...
Cleary, Radford M. Neal, and Ian H. Witten. Arithmetic coding for data compression.
- John G Cleary
- M Radford
- Ian H Neal
- Witten
- John
Frank Bossen, Gabriel Taubin and Claudio Silva. Efficient compression of non-manifold polygonal meshes.
- André Guéziec
- Frank Bossen
- Gabriel Taubin
- Claudio Silva