Angular Prior and Direct Coding Mode for Point Cloud Tree Representation

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Solution Overview

Problem

Existing methods for compressing point cloud data, particularly in tree-based structures, face challenges in efficiently coding geometry and handling isolated points, leading to increased computational burden and reduced compression performance.

Innovation Solution

The proposed solution involves a combination of Inferred Direct Coding Mode (IDCM) and a simplified angular coding mode, where IDCM is applied to isolated nodes eligible for angular coding, reducing the number of nodes to process and simplifying the encoding algorithm.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If angular coding mode is applied to all nodes, then compression performance is improved, but decoding time increases significantly

Engineering Contradiction:

Improvecompression performanceVSAvoiddecoding time

Core Design Contradiction:

Loss of informationVSLoss of time

Solution Approach 1:

The patent applies different coding strategies to different types of nodes based on their characteristics. Angular coding mode is applied selectively to non-isolated nodes where it provides compression benefits, while IDCM is used for isolated nodes to reduce processing complexity. This local differentiation resolves the contradiction by optimizing for compression where needed while minimizing processing time where angular coding provides little benefit.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the point cloud data processing into two distinct paths: one for isolated nodes using IDCM and another for non-isolated nodes using angular coding mode. This segmentation allows the system to apply the most appropriate coding method to each segment, achieving overall compression improvement without uniformly increasing decoding time for all nodes.

Inventive Principle:

Principle #1Segmentation

2Productivity

If IDCM is applied to more nodes, then decoding speed is improved, but compression performance deteriorates

Engineering Contradiction:

Improvedecoding speedVSAvoidcompression performance

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The patent uses a hybrid approach where the coding method is locally optimized for each node type. Isolated nodes use IDCM for fast processing, while non-isolated nodes use angular coding mode for better compression. This local quality differentiation resolves the contradiction by applying speed optimization only where appropriate rather than universally.

Inventive Principle:

Principle #3Local quality

3Loss of information

If angular coding mode is used for isolated nodes, then compression gains are achieved, but processing complexity increases

Engineering Contradiction:

Improvecompression gainsVSAvoidprocessing complexity

Core Design Contradiction:

Loss of informationVSDevice complexity

Solution Approach 1:

Instead of applying the more complex angular coding mode to all nodes, the patent inverts the approach by using the simpler IDCM method for isolated nodes and reserving angular coding for non-isolated nodes where it provides significant compression benefits. This inversion reduces overall processing complexity while maintaining compression effectiveness.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentEP4052473B1Angular prior and direct coding mode for tree representation coding of a point cloud

Publication Date: 2025.05.07 BLACKBERRY LTD

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AI summary

A method of encoding or decoding a point cloud for representing a three-dimensional location of an object, the point cloud being generated by a device comprising a plurality of beam emitters. The method comprises using information from the beam emitter such as the location and angle of each beam emitter to more efficiently represent the point cloud data.