Octree Planar Context Coding for Point Cloud Compression
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Solution Overview
Problem
Existing point cloud compression methods, particularly for non-natural environments, fail to efficiently exploit the planar nature of some environments, leading to suboptimal compression performance in uniform partitioning-based tree structures like octrees.
Innovation Solution
Implement a planar coding mode that signals planarity in tree-based structures, using eligibility criteria and context-adaptive coding to improve compression by inferring occupancy patterns based on planarity, especially for horizontally or vertically aligned volumes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform partitioning-based tree structures (octrees) are used for point cloud compression, then the coding structure is simple and regular, but compression performance is suboptimal for environments with planar features
Solution Approach 1:
The patent introduces a dynamic planar mode that can be activated based on the geometric characteristics of the point cloud data. The coding structure transitions from static uniform partitioning to dynamic adaptive partitioning when planarity is detected, allowing the system to optimize compression performance for specific data patterns while maintaining simplicity for general cases
Solution Approach 2:
The patent changes the partitioning parameters from fixed uniform division to adaptive division based on planarity detection. When planar features are detected, the partitioning strategy is modified to exploit the planar geometry, changing the structural parameters of the coding tree to achieve better compression
2Loss of information
If planar coding mode is implemented to exploit planar features, then compression efficiency improves for planar environments, but device complexity increases
Solution Approach 1:
The patent performs preliminary planarity detection and mode selection before the actual coding process. By determining whether planar mode should be applied in advance, the system avoids complex real-time decisions during coding, reducing the overall computational complexity while still achieving compression improvements
Solution Approach 2:
The planar mode coding mechanism is self-adaptive, automatically detecting planar features and selecting the appropriate coding strategy without requiring complex external control or configuration. The system serves itself by making autonomous decisions based on the data characteristics
3Device complexity
If occupancy bits are coded without considering planarity, then coding process is simple, but more bits are required to represent the same spatial information
Solution Approach 1:
The patent applies planar mode selectively only to regions where planar features are detected, rather than applying complex coding to the entire point cloud. This partial application of the advanced coding technique reduces the overall bit requirement while avoiding the complexity of implementing it universally
Data Source
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AI summary
Method and devices for coding point cloud data using a planar coding mode. The planar coding mode may be signaled using in a planar mode flag to signal that a volume is planar. A planar volume has all of its occupied child nodes on one side of a plane bisecting the volume. A planar position flag may signal which side of the volume is occupied. Entropy coding may be used to code the planar mode flag and/or the planar position flag. Context determination for coding may take into account one or more of whether a parent volume containing the volume is planar in occupancy, occupancy of a neighbouring volume at a parent depth, distance between the volume and a closest already-coded occupied volume at a same depth as the volume, plane position, if any, of the closest already-coded occupied volume, and a position of the volume within the parent volume.