Point Cloud Encoder Planar Mode Flag Merging

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Solution Overview

Problem

Current point cloud compression methods, particularly Geometry-based Point Cloud Compression (GPCC), are inefficient in sparse point clouds due to excessive bit usage in planar mode encoding, as they encode individual flags for each direction even when the node is eligible for planar mode in multiple directions.

Innovation Solution

The method determines eligibility for planar mode in at least two directions and uses a single planar flag to indicate planar context information, reducing the number of bits needed for encoding and decoding by combining context information across directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If individual planar flags are encoded for each direction, then planar mode encoding is applied to eligible nodes, but the number of bits required increases excessively for sparse point clouds

Engineering Contradiction:
Improvecompression efficiencyVSAvoidnumber of bits
Core Design Contradiction:
Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent merges multiple planar flags into a single unified planar flag that indicates planar context information for multiple directions simultaneously. This combining approach reduces the number of bits from encoding individual directional flags to encoding a single shared flag, directly addressing the contradiction between maintaining encoding precision and reducing bit quantity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single planar flag serves multiple functions by indicating planar context information across different directions (e.g., XY plane, XZ plane, YZ plane) rather than requiring separate flags for each direction. This multi-functionality allows the same flag to replace multiple directional indicators, reducing bit usage while preserving encoding accuracy for sparse point clouds.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If planar mode is encoded for all three directions independently, then comprehensive planar context is captured, but device complexity increases

Engineering Contradiction:
Improveencoding accuracyVSAvoidencoding complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple planar mode indicators into a single planar flag structure that can represent planar context across different directions. This merging reduces the complexity of the encoding system by eliminating redundant flag handling logic while maintaining the ability to accurately represent planar geometries through the unified flag's contextual information.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentUS20240404118A1Method of encoding and decoding, encoder, and decoder
Publication Date: 2024.12.05 BEIJING XIAOMI MOBILE SOFTWARE CO LTD
  • US20240404118A1 patent drawing
  • US20240404118A1 patent drawing
  • US20240404118A1 patent drawing

AI summary

A method for encoding a point cloud to generate a bitstream of compressed point cloud data is provided, wherein the point cloud's geometry is represented by an octree-based structure with a plurality of nodes having parent-child relationships by recursively splitting a volumetric space containing the point cloud into sub-volumes each associated with a node of the octree-based structure. The method includes: determining eligibility of planar mode for a present node to be encoded for at least two directions; in the case of eligibility of planar mode in at least two directions of the present node, determining one planar flag indicating planar context information for the at least two directions; and entropy encoding occupancy of the present node based on the determined planar context information to produce encoded data for the bitstream.