Frédéric Payan

An efficient bit allocation for compressing normal meshes with an error-driven quantization

We propose a new wavelet compression algorithm based on the rate-distortion optimization for densely sampled triangular meshes. Exploiting the normal remesher of Guskov et al., the proposed algorithm includes a wavelet transform and an original bit allocation optimizing the quantization of the wavelet coefficients. The allocation process minimizes the reconstruction error for a given bit budget. As distortion measure, we use the mean square error of the normal mesh quantization, expressed according to the quantization error of each subband. We show that this metric is a suitable criterion to evaluate the reconstruction error, i.e., the geometric distance between the input mesh and the quantized normal one. Moreover, to design a fast bit allocation, we propose a model-based approach, depending on distribution of the wavelet coefficients. Compared to the state-of-the-art methods for normal meshes, our algorithm provides improvements in coding performance, up to +2.5 dB compared to the original zerotree coder.

Technical Section: Temporal wavelet-based compression for 3D animated models

We present an efficient compression scheme for animated sequences of triangular meshes of the same connectivity. The proposed algorithm exploits the temporal coherence of the geometry component by using a temporal wavelet filtering. The quantization of the resulting wavelet coefficients is then optimized by a bit allocation process. This process dispatches the bit budget across the coefficient subbands according to their influence on the quality of the reconstructed sequence for one specific user-given bitrate. The proposed scheme is simple, fast, flexible, and scalable in frame rate and bitrate. Moreover, simulation results show that our approach is competitive for any kind of animated models, whatever the characteristics (parametrically coherent or not, fine/coarse meshes...), contrary to the related works.

Temporal Wavelet-based Geometry Coder for 3D Animated models

We present an efficient compression scheme for animated sequences of triangular meshes of the same connectivity. The proposed algorithm exploits the temporal coherence of the geometry component by using a temporal wavelet filtering. The quantization of the resulting wavelet coefficients is then optimized by a bit allocation process. This process dispatches the bit budget across the coefficient subbands according to their influence on the quality of the reconstructed sequence for one specific user-given bitrate. The proposed scheme is simple, fast, flexible, and scalable in frame rate and bitrate. Moreover, simulation results show that our approach is competitive for any kind of animated models, whatever the characteristics (parametrically coherent or not, fine/coarse meshes...), contrary to the related works.

Multiresolution 3D mesh compression

In this paper, we propose an efficient low complexity compression scheme for densely sampled irregular 3D meshes. This scheme is based on 3D multiresolution analysis (3D discrete wavelet transform) and includes a model-based bit allocation process across the wavelet subbands. Coordinates of 3D wavelet coefficients are processed separately and statistically modeled by a generalized Gaussian distribution. This permits an efficient allocation even at a low bitrate and with a very low complexity. We introduce a predictive geometry coding of LF subbands and topology coding is made by using an original edge-based method. The main idea of our approach is the model-based bit allocation adapted to 3D wavelet coefficients and the use of EBCOT coder to efficiently encode the quantized coefficients. Experimental results show compression ratio improvement for similar reconstruction quality compared to the well-known PGC method.

3D multiresolution context-based coding for geometry compression

In this paper, we propose a 3D geometry compression technique for densely sampled surface meshes. Based on a 3D multiresolution analysis (performed by a 3D Discrete wavelet transform for semiregular meshes), this scheme includes a model-based bit allocation process across the wavelet subbands and an efficient surface adapted weighted criterion for 3D wavelet coefficient coordinates. This permits to highly improve the visual quality of quantized meshes obtained by classical bit allocation based on MSE distortion. Moreover, the coefficients are encoded with an original 3D context-based bitplane arithmetic coder. The main contribution of this paper is the introduction of 3D multiresolution contexts adapted to 3D semiregular mesh geometry information.

3D mesh wavelet coding using efficient model-based bit allocation

In this paper, we propose an efficient low complexity geometry compression scheme for densely sampled irregular 3D meshes. This scheme is based on 3D multiresolution analysis (3D discrete wavelet transform) and includes a model-based bit allocation process across the wavelet subbands. Coordinates of 3D wavelet coefficients are processed separately and statistically modeled by a generalized Gaussian distribution. This permits an efficient allocation even at low bitrate with very low complexity. Moreover, we introduce predictive geometry coding of LF subbands by taking into account the correlation of the coarsest level coefficients. Finally, we use the EBCOT coder to efficiently encode the quantized coefficients.

Deforming surface simplification based on dynamic geometry sampling

Although deforming surfaces are frequently used in numerous domains (scientific applications, games...), only few works have been proposed until now for simplifying such data. However, these time-varying surfaces are generally represented as oversampled triangular meshes with a static connectivity, involving a large number of unnecessary details for some frames. Among the related works, some methods provide globally good results, but fine details appearing during the animation are not always well-preserved, because of a static geometry sampling. We propose a new simplification method for deforming surfaces based on a dynamic geometry sampling. The idea is to compute one coarse version at the first frame, and then to progressively update the coarse sampling for the subsequent frames. In order to optimally approximate each frame, vertices are added or removed following the appearance or disappearance of fine details in the frames. Our approach is fast, easy to implement, and produces good quality time-varying approximations with well-preserved fine details, at any given frame.

Semi-Regular Triangle Remeshing: A Comprehensive Study

Semi‐regular triangle remeshing algorithms convert irregular surface meshes into semi‐regular ones. Especially in the field of computer graphics, semi‐regularity is an interesting property because it makes meshes highly suitable for multi‐resolution analysis. In this paper, we survey the numerous remeshing algorithms that have been developed over the past two decades. We propose different classifications to give new and comprehensible insights into both existing methods and issues. We describe how considerable obstacles have already been overcome, and discuss promising perspectives.

Feature-preserving Direct Blue Noise Sampling for Surface Meshes

We present a new direct Poisson disk sampling for surface meshes. Our objective is to sample triangular meshes, while satisfying good blue noise properties, but also preserving features. Our method combines a feature detection technique based on vertex curvature, and geodesic-based dart throwing. Our method is fast, automatic, and experimental results prove that our method is well-suited to CAD models, since it handles sharp features and high genus meshes, while having good blue noise properties.

Adaptive semi-regular remeshing: A Voronoi-based approach

We propose an adaptive semi-regular remeshing algorithm for surface meshes. Our algorithm uses Voronoi tessellations during both simplification and refinement stages. During simplification, the algorithm constructs a first centroidal Voronoi tessellation of the vertices of the input mesh. The sites of the Voronoi cells are the vertices of the base mesh of the semi-regular output. During refinement, the new vertices added at each resolution level by regular subdivision are considered as new Voronoi sites. We then use the Lloyd relaxation algorithm to update their position, and finally we obtain uniform semi-regular meshes. Our algorithm also enables adaptive remeshing by tuning a threshold based on the mass probability of the Voronoi sites added by subdivision. Experimentation shows that our technique produces semi-regular meshes of high quality, with significantly less triangles than state of the art techniques.