Progressive Mesh Compression Using Adaptive Collapse Operators
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Solution Overview
Problem
Existing progressive mesh compression methods are inefficient in balancing quality and bit-rate, as they often rely on a single type of edge collapse operator, which can result in either high-quality but data-intensive models or lower-quality models with reduced bit-rate, failing to efficiently transmit detailed geometric models over networks.
Innovation Solution
The method involves generating multiple levels of detail (LODs) using two types of edge collapse operators, switching between full-edge and half-edge collapse operators based on a switching condition, to balance distortion and bit-rate, allowing for efficient transmission and display of progressively compressed meshes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single type of edge collapse operator is used throughout the compression process, then the implementation is simple, but the balance between quality and bit-rate is poor
Solution Approach 1:
The compression process is segmented into different stages, with each stage using a specific type of collapse operator. The first stage uses full-edge collapse operators to generate initial LODs, and the second stage uses half-edge collapse operators to generate subsequent LODs. This segmentation allows each operator type to be optimized for its specific function, improving the overall quality-bit-rate balance while keeping each stage's implementation relatively simple
Solution Approach 2:
The system dynamically switches between different types of collapse operators based on the current compression stage and quality requirements. The switching condition is triggered when transitioning from generating the first plurality of LODs to the second plurality of LODs, allowing the system to adapt its compression strategy to maintain optimal quality-bit-rate balance throughout the progressive compression process
2Manufacturing precision
If full-edge collapse operators are used to maintain high quality, then the model quality is preserved, but the bit-rate increases
Solution Approach 1:
Different regions of the mesh compression process are assigned different operator types based on local quality requirements. Full-edge collapse operators are used in the initial stage where higher quality is needed to establish the base LODs, while half-edge collapse operators are used in subsequent stages where moderate quality reduction is acceptable to achieve lower bit-rates. This local differentiation optimizes the quality-bit-rate tradeoff at each compression stage
3Quantity of substance
If half-edge collapse operators are used to reduce bit-rate, then the data size is reduced, but the model quality deteriorates
Solution Approach 1:
The full-edge collapse operators are applied in advance to generate the first plurality of LODs with high quality before switching to half-edge collapse operators. This preliminary high-quality compression establishes a solid foundation that allows subsequent half-edge operations to reduce bit-rate more effectively without causing excessive quality deterioration, as the base structure has already been optimized
Data Source
AI summary
An encoder includes a processor and a memory. The encoder generates a first plurality of levels of detail (LODs) and associated first type of vertex split records, each of the first type of vertex split records associated with an LOD of the first plurality of LODs is generated using a first type of collapse operator. The encoder initiates a switch from using the first type of collapse operator to a second type of collapse operator in response to a switching condition being satisfied. The encode further a second plurality of LODs and associated second type of vertex split records, each of the second type of vertex split records associated with a LOD of the second plurality of LODs is generated using the second type of collapse operator.