Transmissions over wireless and other unreliable networks can lead to packet loss. An area that has received limited research attention is how to tailor multimedia information taking into account the way packets are lost. We provide a brief overview of our research on designing a 3D perceptual quality metric integrating two important factors, resolution of texture and resolution of mesh, which control transmission bandwidth. We then suggest alternative strategies for packet 3D transmission of both texture and mesh. These strategies are then compared with respect to preserving 3D perceptual quality under packet loss in ad hoc wireless networks. Experiments are conducted to study how the time between consecutive packet transmission and packet size affects loss in wireless channels. A preliminary model for estimating the optimal packet size is then proposed.

Transmissions over unreliable networks, for example, wireless, can lead to packet loss. An area that has received limited research attention is how to tailor multimedia information taking into account the way packets are lost. We provide a brief overview of our research on designing a 3D perceptual quality metric integrating two important factors, resolution of texture and resolution of mesh, which control transmission bandwidth, followed by a suggestion on alternative strategies for packet 3D transmission of both texture and mesh. These strategies are then compared with respect to preserving 3D perceptual quality under packet loss in ad hoc wireless networks. Experiments are conducted to study how buffer size, sending rate, sending intervals, and packet size can affect loss in unreliable channels. A model for estimating the optimal packet size is then proposed. We derive the optimal number of packets based on this model, and relate the theoretical derivations to actual network data.

We describe transmission of 3D objects represented by texture and mesh over unreliable networks, extending our earlier work for regular mesh structure to arbitrary meshes and considering linear versus cubic interpolation. Our approach to arbitrary meshes considers stripification of the mesh and distributing nearby vertices into different packets, combined with a strategy that does not need texture or mesh packets to be retransmitted. Only the valence (connectivity) packets need to be retransmitted; however, storage of valence information requires only 10% space compared to vertices and even less compared to photorealistic texture. Thus, less than 5% of the packets may need to be retransmitted in the worst case to allow our algorithm to successfully reconstruct an acceptable object under severe packet loss. Even though packet loss during transmission has received limited research attention in the past, this topic is important for improving quality under lossy conditions created by shadowing and interference. Results showing the implementation of the proposed approach using linear, cubic, and Laplacian interpolation are described, and the mesh reconstruction strategy is compared with other methods.

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