Scalable L-Infinite Coding of Meshes

Abstract

The paper investigates the novel concept of local-error control in mesh geometry encoding. In contrast to traditional mesh-coding systems that use the mean-square error as target distortion metric, this paper proposes a new L-infinite mesh-coding approach, for which the target distortion metric is the L-infinite distortion. In this context, a novel wavelet-based L-infinite-constrained coding approach for meshes is proposed, which ensures that the maximum error between the vertex positions in the original and decoded meshes is lower than a given upper bound. Furthermore, the proposed system achieves scalability in L-infinite sense, that is, any decoding of the input stream will correspond to a perfectly predictable L-infinite distortion upper bound. An instantiation of the proposed L-infinite-coding approach is demonstrated for MESHGRID, which is a scalable 3D object encoding system, part of MPEG-4 AFX. In this context, the advantages of scalable L-infinite coding over L-2-oriented coding are experimentally demonstrated. One concludes that the proposed L-infinite mesh-coding approach guarantees an upper bound on the local error in the decoded mesh, it enables a fast real-time implementation of the rate allocation, and it preserves all the scalability features and animation capabilities of the employed scalable mesh codec.

Efficient error control in 3D mesh coding

“…The L-infinite distortion has been investigated in the context of coding of 3D graphics only recently [1]. With this respect, [1] proposes a scalable L-infinite mesh coding approach, simultaneously performing local error control and providing scalability in L-infinite sense.…”

“…With this respect, [1] proposes a scalable L-infinite mesh coding approach, simultaneously performing local error control and providing scalability in L-infinite sense. The L-infinite coding approach is instantiated by using the MESHGRID coding system [2].…”

“…The L-infinite coding approach is instantiated by using the MESHGRID coding system [2]. Additionally, an L-infinite distortion estimator is proposed [1], expressing the L-infinite distortion in the spatial domain as a function of quantization errors occurring in the wavelet domain. Employing this estimator enables an optimized rate-allocation for given local-error bounds, without performing an actual decoding of the mesh.…”

“…Employing this estimator enables an optimized rate-allocation for given local-error bounds, without performing an actual decoding of the mesh. In addition, a fast algorithm for solving the rate-distortion optimization problem is designed, enabling a real-time implementation of the rateallocation [1].…”

“…In this survey paper we give an overview of our L-infinite estimators recently introduced in [1] and investigate how the L-infinite distortion metric performs compared to the L-2 distortion metric, when both are instantiated for the MESHGRID coding system [2].…”