Wavelet-based scalable L-infinity-oriented coding of MPEG-4 MESHGRID surface models

Abstract

MESHGRID is a novel, compact, multi-scalable and animation-friendly 3D object representation method, which is part of MPEG-4, and which resides in the Animation Framework Extensions (AFX) toolset. The paper introduces the novel concept of local error control for arbitrary mesh encoding. In this sense, the paper proposes a new wavelet-based L ∞ -constrained coding technique for MESHGRID models, generating a fully scalable L ∞ -oriented bit-stream. The advantages of scalable L ∞ -oriented coding over 2 L coding are experimentally demonstrated.

Statistical L-infinite distortion estimation in scalable coding of meshes

“…In a mesh coding application, the Linfinite distortion corresponds to the maximum absolute difference between the actual and decoded vertex positions in the reconstructed mesh. In this context, a data-independent estimator for the L-infinite norm has been formulated in our previous work [6], in the context of MESHGRID.…”

“…The L-infinite distortion estimator presented in [6] is data independent, as it is computed solely based on worst-casescenario assumptions about the error contributions originating from the different wavelet subbands. Consequently, the wavelet coefficients need not to be effectively decoded, and no inverse wavelet transform needs to be performed.…”

“…the mesh, and instantiate it using our scalable MESHGRID coding system. This newly proposed statistical L-infinite mesh coder increases the accuracy of the MAXAD estimator while retaining all the characteristics of the L-infinite approach we defined in [6], i.e. it is scalable, real-time, and it guarantees the best rate-allocation for any imposed MAXAD upper-bound.…”

“…In this paper, following our ideas in [6]- [8], we propose a novel L-infinite mesh coding approach based on a statistical analysis of the input data, i.e. the mesh, and instantiate it using our scalable MESHGRID coding system.…”

“…From this point of view, a more appropriate target distortion metric is one that guarantees a maximum local error in the decoded mesh. Based on this reasoning, we have recently explored an alternative approach [6], wherein the target distortion metric is the L-infinite distortion, corresponding to the MAXimum Absolute Difference (MAXAD) between the actual vertex positions and the decoded positions in the reconstructed mesh.…”