Efficient 3D data compression through parameterization of free-form surface patches

This paper presents a new method for 3D data compression based on parameterization of surface patches. The technique is applied to data that can be defined as single valued functions; this is the case for 3D patches obtained using standard 3D scanners. The method defines a number of mesh cutting planes and the intersection of planes on the mesh defines a set of sampling points. These points contain an explicit structure that allows us to define parametrically both x and y coordinates. The z values are interpolated using high degree polynomials and results show that compressions over 99% are achieved while preserving the quality of the mesh

Novel 3D compression methods for geometry, connectivity and texture

A large number of applications in medical visualization, games, engineering design, entertainment, heritage, e-commerce and so on require the transmission of 3D models over the Internet or over local networks. 3D data compression is an important requirement for fast data storage, access and transmission within bandwidth limitations. The Wavefront OBJ (object) file format is commonly used to share models due to its clear simple design. Normally each OBJ file contains a large amount of data (e.g. vertices and triangulated faces, normals, texture coordinates and other parameters) describing the mesh surface. In this paper we introduce a new method to compress geometry, connectivity and texture coordinates by a novel Geometry Minimization Algorithm (GM-Algorithm) in connection with arithmetic coding. First, each vertex (x, y, z) coordinates are encoded to a single value by the GM-Algorithm. Second, triangle faces are encoded by computing the differences between two adjacent vertex locations, which are compressed by arithmetic coding together with texture coordinates. We demonstrate the method on large data sets achieving compression ratios between 87%—99% without reduction in the number of reconstructed vertices and triangle faces. The decompression step is based on a Parallel Fast Matching Search Algorithm (Parallel-FMS) to recover the structure of the 3D mesh. A comparative analysis of compression ratios is provided with a number of commonly used 3D file formats such as VRML, OpenCTM and STL highlighting the performance and effectiveness of the proposed method

Geometric 3D point cloud compression

The use of 3D data in mobile robotics applications provides valuable information about the robot’s environment but usually the huge amount of 3D information is unmanageable by the robot storage and computing capabilities. A data compression is necessary to store and manage this information but preserving as much information as possible. In this paper, we propose a 3D lossy compression system based on plane extraction which represent the points of each scene plane as a Delaunay triangulation and a set of points/area information. The compression system can be customized to achieve different data compression or accuracy ratios. It also supports a color segmentation stage to preserve original scene color information and provides a realistic scene reconstruction. The design of the method provides a fast scene reconstruction useful for further visualization or processing tasks.This work has been supported by the Spanish Government DPI2013-40534-R grant

Compression sans perte de maillages triangulaires adaptée aux applications métrologiques

La compression est un incontournable lorsque des modèles triangulaires 3D massifs doivent être transmis via un réseau de communication. La compression se doit d'être sans perte lorsque les modèles sont utilisés à des fins métrologiques. Cependant, les modèles capturés par scanneurs 3D contiennent généralement des artefacts de numérisation tels que la présence de trous dans le maillage, de petits regroupements distincts de triangles sous forme de surfaces ou de volumes ainsi que de singularités non-manifold (c.-à-d. un sommet appartenant à deux regroupement de triangles distincts). Ces aberrations rendent les techniques de compression standards inaptes à compresser sans échec le modèle. Ce mémoire propose une extension à une technique de compression et décompression sans perte des données topologiques nommée Edgebreaker. Le remplissage des trous par l'addition d'un sommet, l'insertion de faces triangulaires afin de lier les îlots ainsi que la duplication des sommets non-manifold sont proposées comme étapes de prétraitement afin de rendre le modèle compatible avec l'approche standard d'Edgebreaker. Les résultats obtenus démontrent que la solution proposée permet la compression sans perte de modèles hautement bruités à de hauts taux de compression. Les taux de compression résultants obtenus par notre approche se comparent également avec les taux observables pour des modèles sans imperfections compressés par Edgebreaker

An EdgeBreaker-based Efficient Compression Scheme for Regular Meshes

One of the most natural measures of regularity of a triangular mesh homeomorphic to the two-dimensional sphere is the fraction of its vertices having degree 6. We construct a linear-time connectivity compression scheme build upon Edgebreaker which explicitly takes advantage of regularity and prove rigorously that, for sufficiently large and regular meshes, it produces encodings not longer than 0.811 bits per triangle: 50 % below the information-theoretic lower bound for the class of all meshes. Our method uses predictive techniques enabled by the Spirale Reversi decoding algorithm. Key words: triangle mesh, compression, information-theoretic lower bound

An Edgebreaker-Based Efficient Compression Scheme for Regular Meshes

One of the most natural measures of regularity of a triangular mesh homeomorphic to the two-dimensional sphere is the fraction of its vertices having degree 6. We construct a linear-time connectivity compression scheme build upon Edgebreaker which explicitly takes advantage of regularity and prove rigorously that, for suciently large and regular meshes, it produces encodings not longer than 0:811 bits per triangle: 50% below the information-theoretic lower bound for the class of all meshes. Our method uses predictive techniques enabled by the Spirale Reversi decoding algorithm. 1 Introduction Geometric data is typically represented by meshes, often triangular. Frequently, there is need to access such data via a network connection and, in such cases, bandwidth tends to become a serious obstacle to interactivity. An obvious way out of this problem is to use compressed representations. The standard representation of a triangular mesh consists of two parts: connectivity and vertex coord..

3D modelling using partial differential equations (PDEs).

Partial differential equations (PDEs) are used in a wide variety of contexts in computer science ranging from object geometric modelling to simulation of natural phenomena such as solar flares, and generation of realistic dynamic behaviour in virtual environments including variables such as motion, velocity and acceleration. A major challenge that has occupied many players in geometric modelling and computer graphics is the accurate representation of human facial geometry in 3D. The acquisition, representation and reconstruction of such geometries are crucial for an extensive range of uses, such as in 3D face recognition, virtual realism presentations, facial appearance simulations and computer-based plastic surgery applications among others. The principle aim of this thesis should be to tackle methods for the representation and reconstruction of 3D geometry of human faces depending on the use of partial differential equations and to enable the compression of such 3D data for faster transmission over the Internet. The actual suggested techniques are based on sampling surface points at the intersection of horizontal and vertical mesh cutting planes. The set of sampled points contains the explicit structure of the cutting planes with three important consequences: 1) points in the plane can be defined as a one dimensional signal and are thus, subject to a number of compression techniques; 2) any two mesh cutting planes can be used as PDE boundary conditions in a rectangular domain; and 3) no connectivity information needs to be coded as the explicit structure of the vertices in 3D renders surface triangulation a straightforward task. This dissertation proposes and demonstrates novel algorithms for compression and uncompression of 3D meshes using a variety of techniques namely polynomial interpolation, Discrete Cosine Transform, Discrete Fourier Transform, and Discrete Wavelet Transform in connection with partial differential equations. In particular, the effectiveness of the partial differential equations based method for 3D surface reconstruction is shown to reduce the mesh over 98.2% making it an appropriate technique to represent complex geometries for transmission over the network