Point Cloud Transform Coefficient Partition Coding for Sparse Prediction

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current graph-based point cloud compression technologies face inefficiencies in compression efficiency when there are not enough neighboring attribute samples available for prediction, particularly in lossy compression for real-time communications and dynamic mapping applications.

Innovation Solution

The method involves decomposing transform coefficients into set-index values and symbol-index values, partitioning them into sets, entropy-coding the set-index values, and bypass-coding the symbol-index values to improve compression efficiency by leveraging frequency-sorted look-up tables and caches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If distance-based weighted average prediction is used for attribute coding, then prediction accuracy is improved when enough neighboring samples are available, but compression efficiency deteriorates when neighboring samples are insufficient

Engineering Contradiction:
Improveprediction accuracyVSAvoidcompression efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent uses frequency-sorted look-up tables and caches to store and reuse previously computed transform coefficients and their coded representations. When neighboring samples are insufficient, the system copies and reuses existing coefficient patterns from the look-up table, maintaining compression efficiency without requiring additional neighboring samples for prediction.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent pre-computes and stores transform coefficients in frequency-sorted look-up tables before actual encoding. This preliminary action allows the system to quickly retrieve and reuse pre-coded coefficient patterns during compression, eliminating the need for complex real-time predictions when neighboring samples are limited.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If traditional entropy coding is applied to all transform coefficients, then coding completeness is maintained, but computational complexity and memory usage increase

Engineering Contradiction:
Improvecoding completenessVSAvoidcomputational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts frequently occurring transform coefficient patterns and stores them in frequency-sorted look-up tables. During encoding, these pre-extracted patterns are directly retrieved and reused, eliminating the need to apply complex entropy coding algorithms to every coefficient individually, thus reducing computational complexity while maintaining coding completeness.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the coding parameter from full entropy coding of each coefficient to selective reuse of pre-coded patterns from look-up tables. This parameter change in the coding strategy reduces computational complexity by avoiding redundant encoding operations while preserving the completeness of coefficient representation through the cached patterns.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11651521B2Techniques and apparatus for alphabet-partition coding of transform coefficients for point cloud compression
Publication Date: 2023.05.16 TENCENT AMERICA LLC
  • US11651521B2 patent drawing
  • US11651521B2 patent drawing
  • US11651521B2 patent drawing

AI summary

A method, apparatus, and computer-readable medium for point cloud coefficient coding are provided. The method may include receiving compressed point cloud data based on set-index values and symbol-index values; and entropy-decoding the set-index values based on the compressed point cloud data. The symbol-index values may be bypass-decoded based on the compressed point cloud data, and the set-index values and symbol-index values may be combined into transform coefficients associated with cloud point data.