Boundary UV Prediction for Dynamic Mesh Compression
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Solution Overview
Problem
Existing mesh compression standards do not effectively handle dynamic meshes with time varying connectivity information and attribute maps, particularly under real-time constraints, and fail to support volumetric acquisition techniques.
Innovation Solution
A method for predicting sampled 2D coordinates from previously coded coordinates and deriving prediction residuals to reconstruct boundary vertices in a 2D mesh, using UV parameterization and efficient compression techniques for dynamic meshes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing mesh compression standards (IC, MESHGRID, FAMC) are used for dynamic meshes with constant connectivity, then compression is achieved for time varying geometry and vertex attributes, but they fail to handle time varying connectivity information and attribute maps
Solution Approach 1:
The patent applies dynamics by making the mesh connectivity and attribute maps variable over time rather than constant. The system handles dynamic meshes where connectivity information changes between frames, using temporal prediction to exploit correlations between consecutive frames while accommodating connectivity variations through specialized coding modes for boundary vertices and connectivity changes.
Solution Approach 2:
The patent changes the parameter representation by introducing UV coordinate parameterization for boundary vertices and using prediction residuals to represent changes in connectivity and attribute maps. Instead of encoding absolute positions, the system encodes differences from predicted values, adapting the parameter space to reduce redundancy in dynamic mesh sequences.
2Productivity
If volumetric acquisition techniques are used under real-time constraints, then 3D mesh data is acquired, but the generated dynamic meshes have time varying connectivity that existing standards do not support
Solution Approach 1:
The patent segments the mesh into interior vertices and boundary vertices, treating them differently in the encoding process. Boundary vertices, which are more likely to change connectivity in volumetric acquisition, are specially handled with UV parameterization and predictive coding, while interior vertices use standard encoding. This segmentation allows the system to accommodate real-time volumetric acquisition outputs while maintaining compatibility with existing standards for the majority of vertices.
Solution Approach 2:
The patent introduces UV coordinates as an intermediary representation for boundary vertices. Instead of directly encoding changing connectivity information, the system uses UV parameterization as an intermediate step that maps boundary vertices to a 2D parameter space, making it easier to predict and encode connectivity changes while maintaining compatibility with standard mesh formats.
3Measurement precision
If boundary vertex information is fully encoded in dynamic meshes, then complete mesh reconstruction is achieved, but data size increases significantly for real-time applications
Solution Approach 1:
The patent performs preliminary prediction of boundary vertex positions using UV coordinates and temporal correlation from previous frames. By predicting where boundary vertices are likely to be before encoding, the system only needs to transmit the difference (residual) between predicted and actual positions, significantly reducing the data required while maintaining reconstruction accuracy.
Solution Approach 2:
The system uses feedback from previously coded frames to predict current boundary vertex positions. The decoder uses the same prediction logic as the encoder, utilizing temporal correlations and UV parameterization to reconstruct boundary vertices. This feedback mechanism allows accurate reconstruction with minimal transmitted data, as only prediction residuals need to be encoded and transmitted.
Data Source
AI summary
A method performed by at least one processor in a decoder includes receiving a coded video bitstream that includes a compressed two dimensional (2D) mesh corresponding to a surface of three dimensional (3D) volumetric object. The method includes predicting a sampled 2D coordinate from at least one previously coded sampled 2D coordinate included in the compressed mesh. The method includes deriving a prediction residual associated with the sampled 2D coordinate. The method further includes reconstructing a 2D coordinate corresponding to a boundary vertex based on the predicted sampled 2D coordinate and the derived prediction residual.