Polygon Mesh Connectivity Coding via Pivot Vertex Edge Offsets

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Solution Overview

Problem

Existing methods for encoding and decoding polygon mesh connectivity information are inefficient, particularly in signaling split vertex offsets, which can occupy a large portion of the connectivity bitstream.

Innovation Solution

The proposed method determines the split vertex by iteratively searching in different rings with respect to the pivot vertex and signals the number of edges between the pivot vertex and the split vertex, allowing for more efficient coding of connectivity information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If traditional methods are used to signal split vertex offsets in polygon mesh compression, then connectivity information can be encoded, but the bitstream size becomes large and compression efficiency deteriorates

Engineering Contradiction:

Improveconnectivity information compression efficiencyVSAvoidbitstream size

Core Design Contradiction:

Loss of informationVSQuantity of substance

Solution Approach 1:

The patent changes the parameter being signaled from absolute split vertex indices to relative offsets from the pivot vertex. This parameter transformation reduces the magnitude of values that need to be encoded, allowing for more efficient bit allocation and improved compression of connectivity information in the mesh data structure.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Instead of directly encoding the position of split vertices in the traditional manner, the patent inverts the approach by encoding the offset distance from the pivot vertex to the split vertex. This inverted encoding strategy exploits the spatial locality and typical distribution patterns of vertices in mesh structures, resulting in smaller bitstream requirements.

Inventive Principle:

Principle #13The other way round (Inversion)

2Measurement precision

If Euclidean distances and sorting algorithms are used to determine vertex positions, then accurate spatial relationships are maintained, but computational complexity and processing time increase

Engineering Contradiction:

Improvevertex spatial relationship accuracyVSAvoidcomputational complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and utilizes only the essential topological relationship information needed for mesh connectivity encoding, rather than computing full Euclidean distances. By taking out only the necessary offset data from the pivot vertex, the method maintains sufficient spatial relationship accuracy while eliminating unnecessary computational overhead from complex distance calculations and sorting operations.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS20250157082A1Coding split vertex offsets in polygonal mesh compression

Publication Date: 2025.05.15 TENCENT AMERICA LLC

AI summary

Aspects of the disclosure includes methods and apparatuses for coding connectivity information of a polygon mesh. A method for decoding connectivity information of the polygon mesh includes receiving coded information including a first syntax element of a split vertex incident to a current face that is being processed. The current face is one of a plurality of faces of the polygon mesh. The method includes determining a number of edges between a pivot vertex incident to the current face and another vertex incident to the current face. Each of the edges between the pivot vertex and the other vertex is incident to a respective processed face of the plurality of faces. When the number of edges between the pivot vertex and the other vertex is indicated by the first syntax element, the method includes determining that the other vertex is the split vertex.