Basemesh Patch Syntax for Mixed Mesh and Point Cloud Encoding
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Solution Overview
Problem
The existing V3C standard is inadequate for transmitting the connectivity of points in 3D meshes and lacks mechanisms to efficiently encode sparse meshes, leading to inefficiencies in encoding 3D data and missing attributes of triangle faces.
Innovation Solution
The introduction of a basemesh patch data unit that allows for the transmission of syntax elements related to the basemesh component of a V3C bitstream, enabling the mixing of mesh data with other types like point clouds, and providing flexible data arrangement in 3D and 2D, with texture parameterization and geometry refinement parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the existing V3C standard is used for transmitting 3D mesh data, then point cloud compression is efficient, but mesh connectivity transmission is not supported and sparse mesh encoding is inefficient
Solution Approach 1:
The patch data unit structure is designed to serve multiple functions: it can encode both point cloud data and mesh data (vertices, connectivity, attributes) using the same syntax framework. The generalized vertex attribute information structure can represent different data types (position, color, normal, connectivity) within a unified format, allowing the V3C standard to handle diverse 3D content types without requiring separate encoding mechanisms.
Solution Approach 2:
The mesh data is segmented into patches that can be independently encoded and transmitted. Each patch contains vertex attributes and connectivity information for a specific portion of the mesh, allowing selective transmission of only the necessary data elements. This segmentation enables efficient encoding of sparse meshes by only including present vertices and their connections rather than transmitting complete dense mesh structures.
2Adaptability or versatility
If RAW patches are used to encode sparse point clouds, then sparse data can be transmitted, but encoding efficiency decreases and triangle face attributes are missing
Solution Approach 1:
The methodology performs preliminary organization of mesh data into patches with defined vertex attributes and connectivity relationships before encoding. By pre-structuring the data with proper vertex indexing and attribute association, the encoding process becomes more efficient as it works with organized data structures rather than raw unordered points. This preliminary arrangement enables the encoder to efficiently identify and transmit only the necessary vertices and attributes for sparse representations.
Solution Approach 2:
The patch data unit creates a composite data structure that combines multiple elements (vertex positions, attributes, connectivity information) into a unified encoded format. This composite structure efficiently packages sparse mesh data by integrating geometric information with topological relationships, allowing simultaneous transmission of both position and attribute data in a single cohesive unit rather than separate streams.
3Measurement precision
If mesh data and point clouds are encoded separately, then each data type can be optimized, but data integration and mixed transmission are not possible
Solution Approach 1:
The patch data unit syntax is designed as a universal container that can hold both point cloud data and mesh data within the same bitstream structure. The generalized vertex attribute information can represent different data types (positions, colors, normals, connectivity) using the same encoding framework, allowing seamless mixing of mesh and point cloud content without requiring separate encoding paths or multiple bitstreams.
Data Source
AI summary
A new high-level syntax element referred to as a basemesh patch data unit allows the transmission of syntax elements related to the basemesh component of a V3C bitstream. Previously, the V3C standard did not have any additional patches targeting the basemesh only. A basemesh patch data unit works with the previously disclosed sub-patch concept to provide syntax elements to be used with basemesh bitstream. The basemesh patch data unit allows mesh data and other types of data (e.g., point clouds) to be mixed together at the patch level and generate a richer representation of 3D objects. Furthermore, the basemesh patch data unit expands the concept of sub-meshes and patches by providing a flexible way to arrange the data in 3D (at the basemesh level) and in 2D (at the texture map level) allowing different configurations, instance, multiple attribute images and multiple basemeshes.