Compression of 3D Meshes - Applications, Approaches, Standards

Application of 3D mesh model coding is first presented in this chapter. We then survey the typical existing algorithms in the area of compression of static and dynamic 3D meshes. In an introductory sub-section we introduce basic concepts of 3D mesh models, including data representations, model formats, data acquisitions and 3D display technologies. Furthermore, we introduce several typical 3D mesh formats and give an overview to coding principles of mesh compression algorithms in general, followed by describing the quantitative measures for 3D mesh compression. Then we describe some typical and state-of-the-art algorithms in 3D mesh compression. Compression and streaming of gigantic 3D models are specially introduced. At last, the MPEG4 3D mesh model coding standard is briefed. We conclude this chapter with a discussion providing an overall picture of developments in the mesh coding area and pointing out directions for future research.

Rate-distortion-optimized predictive compression of dynamic 3D mesh sequences

Due to the popularity of polygonal models in Virtual Reality applications, three-dimensional (3D) mesh compression and segmentation are two active areas of 3D object modeling. Most existing 3D compression algorithms compress the whole object to reduce the local storage requirement and the delays in transmitting objects over the Internet. However, in some interactive applications, the client may be interested in particular section(s) of the object. The server needs to segment the object into parts and send them individually or sequentially. This paper presents a segmentation-based 3D mesh compression scheme that can meet this requirement. We propose an efficient eXtended Multi-Ring neighborhood- (XMR) based 3D mesh segmentation algorithm that decomposes the object into meaningful regions. We then compress them separately and put them into one stream. The common boundary triangles that will be used for sticking the regions together are processed and appended to the end of the stream. This is referred to as a region-conquer-and-stitch scheme.

Objective and subjective evaluation of static 3D mesh compression

We introduce an efficient algorithm for real-time compression of temporally consistent dynamic 3D meshes. The algorithm uses mesh connectivity to determine the order of compression of vertex locations within a frame. Compression is performed in a frame to frame fashion using only the last decoded frame and the partly decoded current frame for prediction. Following the predictive coding paradigm, local temporal and local spatial dependencies between vertex locations are exploited. In this framework we present a novel angle preserving predictor and evaluate its performance against other state of the art predictors. It is shown that the proposed algorithm improves up to 25% upon the current state of the art for compression of temporally consistent dynamic 3D meshes.

An efficient algorithm for compression of dynamic time-consistent 3D meshes is presented. Such a sequence of meshes contains a large degree of temporal statistical dependencies that can be exploited for compression using DPCM. The vertex positions are predicted at the encoder from a previously decoded mesh. The difference vectors are further clustered in an octree approach. Only a representative for a cluster of difference vectors is further processed providing a significant reduction of data rate. The representatives are scaled and quantized and finally entropy coded using CABAC, the arithmetic coding technique used in H.264/MPEG4-AVC. The mesh is then reconstructed at the encoder for prediction of the next mesh. In our experiments we compare the efficiency of the proposed algorithm in terms of bit-rate and quality compared to static mesh coding and interpolator compression indicating a significant improvement in compression efficiency.

We present a new approach to dynamic mesh compression, which combines compression with simplification to achieve improved compression results, a natural support for incremental transmission and level of detail. The algorithm allows fast progressive transmission of dynamic 3D content. Our scheme exploits both temporal and spatial coherency of the input data, and is especially efficient for the case of highly detailed dynamic meshes. The algorithm can be seen as an ultimate extension of the clustering and local coordinate frame (LCF)‐based approaches, where each vertex is expressed within its own specific coordinate system. The presented results show that we have achieved better compression efficiency compared to the state of the art methods. Copyright © 2008 John Wiley & Sons, Ltd.

This paper proposes a novel approach for 3D mesh compression, based on a skinning animation technique. The core of the proposed method is a piecewise affine predictor coupled with a skinning model ...

Single-rate near lossless compression of animated geometry

3D mesh compression and segmentation are two active areas of 3D object modeling. Most existing 3D compression algorithms compress the whole object to reduce the local storage requirement and the delays in transmitting objects over the Internet. However, in some interactive applications, the client may be interested in particular section(s) of the object. The server needs to segment the object into pans and send them individually or sequentially. This paper presents a segmentation based 3D mesh compression scheme that can meet this requirement. We propose an efficient eXtend Multi-Ring neighborhood (XMR) based 3D mesh segmentation algorithm that decomposes the object into meaningful regions. Then we compress them separately and put them into one stream. The common boundary triangles that are used for adhering the regions together are processed and appended to the end of the stream. We call this a region-conquer-and-stitch scheme.

In the last decade, the extensive evolution of 3D graphic applications has induced developpers to enhance the 3D mesh compression techniques. Therefore, 3D models are compressed, transmitted and rendered more and more in real-time and with high quality. Moreover, many out-of-core algorithms are proposed to process complex objects. In this paper, we review the major existing technologies for the single-rate and progressive 3D mesh compression. Then, representative out-of-core approaches are surveyed in details. Finally, we represent some parallel schemes exploiting the evolution of many-core GPU architecture.

The compression and watermarking of 3D meshes are very important in many areas of activity including digital cinematography, virtual reality as well as CAD design. However, most studies on 3D watermarking and 3D compression are done independently. To verify a good trade-off between protection and a fast transfer of 3D meshes, this paper proposes a new approach which combines 3D mesh compression with mesh watermarking. This combination is based on a wavelet transformation. In fact, the used compression method is decomposed to two stages: geometric encoding and topologic encoding. The proposed approach consists to insert a signature between these two stages. First, the wavelet transformation is applied to the original mesh to obtain two components: wavelets coefficients and a coarse mesh. Then, the geometric encoding is done on these two components. The obtained coarse mesh will be marked using a robust mesh watermarking scheme. This insertion into coarse mesh allows obtaining high robustness to several attacks. Finally, the topologic encoding is applied to the marked coarse mesh to obtain the compressed mesh. The combination of compression and watermarking permits to detect the presence of signature after a compression of the marked mesh. In plus, it allows transferring protected 3D meshes with the minimum size. The experiments and evaluations show that the proposed approach presents efficient results in terms of compression gain, invisibility and robustness of the signature against of many attacks.

International audience

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.

Mobile robots are useful for environment exploration and rescue operations. In such applications, it is crucial to accurately analyse and represent an environment, providing appropriate inputs for motion planning in order to support robot navigation and operations. 2D mapping methods are simple but cannot handle multilevel or multistory environments. To address this problem, 3D mapping methods generate structural 3D representations of the robot operating environment and its objects by 3D mesh reconstruction. However, they face the challenge of efficiently transmitting those 3D representations to system modules for 3D mapping, motion planning, and robot operation visualization. This paper proposes a quality-driven mesh compression and transmission method to address this. Our method is efficient, as it compresses a mesh by quantizing its transformed vertices without the need to spend time constructing an a-priori structure over the mesh. A visual distortion function is developed to govern the level of quantization, allowing mesh transmission to be controlled under different network conditions or time constraints. Our experiments demonstrate how the visual quality of a mesh can be manipulated by the visual distortion function.