V3c Sub-patch Syntax for 3D Mesh Compression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current 3D mesh compression standards are inadequate for transmitting connectivity information and efficient encoding of sparse meshes, as they require dense meshes and are not optimized for attribute data like triangle faces, and existing methods for point clouds do not effectively handle mesh data or generate texture maps efficiently.
Innovation Solution
The introduction of sub-patches, which allow a single geometry to be described at the patch level with multiple attributes described at the sub-patch level, enabling efficient transmission and decoding of mesh data using orthographic projections to derive texture coordinates and separate geometry and displacement sub-bitstreams, while maintaining compatibility with existing V3C standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If V-PCC projection-based method is used for point cloud compression, then compression efficiency is improved, but the method cannot handle mesh connectivity information and is limited to dense meshes only
Solution Approach 1:
The patent segments mesh data into two distinct components: geometry information (vertex positions) and attribute information (connectivity, colors, textures). This segmentation allows geometry to be encoded using efficient V-PCC projection methods while attribute information is separately encoded to preserve mesh topology and connectivity, resolving the contradiction between compression efficiency and mesh handling capability
Solution Approach 2:
The patent extends the V-PCC projection-based compression framework to handle multiple data types universally. By designing a unified encoding structure that can process both point cloud data and mesh data (geometry and attributes), the method achieves multi-functionality, allowing the same projection infrastructure to serve both dense point clouds and structured meshes with connectivity information
2Adaptability or versatility
If RAW patch data is used to encode sparse meshes, then sparse point clouds can be encoded, but encoding efficiency decreases and attribute data such as triangle face information is lost
Solution Approach 1:
The patent applies preliminary orthographic projection to transform 3D mesh geometry into 2D patch representations before encoding. This preliminary action organizes the spatial data in a structured manner that facilitates more efficient subsequent encoding, allowing sparse meshes to be handled effectively while maintaining encoding efficiency through the structured 2D representation
Solution Approach 2:
The patent creates a composite encoding structure that combines multiple data types (geometry coordinates, connectivity indices, attribute values) into a unified compressed representation. This composite approach integrates the advantages of different encoding methods, preserving both sparse mesh structure and attribute information while achieving efficient compression through coordinated encoding of all components
3Manufacturing precision
If UV Atlas method is used for texture map generation, then texture coordinates can be generated, but processing time increases significantly and optimization is limited to local frames only
Solution Approach 1:
The patent replaces the complex iterative optimization process of traditional UV Atlas methods with a direct orthographic projection mathematical transformation. This substitution eliminates time-consuming iterative adjustments while maintaining texture coordinate accuracy, as the projection provides a deterministic and computationally efficient mapping from 3D mesh surfaces to 2D texture space
Solution Approach 2:
The patent changes the fundamental parameter approach from iterative UV coordinate optimization to direct orthographic projection parameters. By using projection matrices and transformation parameters that can be computed directly without iteration, the method achieves both global optimization (not limited to local frames) and reduced processing time while preserving texture mapping accuracy
Data Source
AI summary
With the concept of sub-patches, the single geometry is described at the patch level, while the multiple attributes are then described at the sub-patch level. One application of the concept is the derivation of texture coordinates using projections for several sections of a mesh surface (affecting the attributes only), whereby the geometry of the whole mesh section uses just one single syntax element.