Point Cloud Attribute Prediction Using Morton-Code Nearest Neighbors

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Solution Overview

Problem

The existing Geometry-based Point Cloud Compression (G-PCC) and Video-based Point Cloud Compression (V-PCC) codecs face inefficiencies in predicting attribute information due to the inability to accurately find the optimal nearest neighbor point during inter prediction, which affects codec efficiency and performance.

Innovation Solution

The proposed solution involves determining a reference point from a prediction point set using Morton code information, establishing a search range, and identifying a nearest neighbor node based on Morton code information to improve the prediction effect for attribute information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a block-based fast search algorithm is used to find nearest neighbor points, then the search speed is improved, but the prediction accuracy deteriorates because the optimal nearest neighbor point cannot be accurately found

Engineering Contradiction:
Improvesearch speedVSAvoidprediction accuracy
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing Morton codes for all points in the reference frame during the encoding process. These pre-computed Morton codes are stored in a lookup structure that enables O(1) retrieval during decoding, eliminating the need for computationally intensive nearest neighbor searches during the actual prediction process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical search process (iteratively comparing distances to find nearest neighbors) with an information-theoretic approach using Morton codes. The Morton code serves as a spatial indexing key that directly maps to neighborhood relationships, substituting complex geometric search operations with simple code lookup and comparison operations.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If the optimal nearest neighbor point is accurately found, then the prediction effect for attribute information is improved, but the codec efficiency deteriorates due to increased computational complexity

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

Solution Approach 1:

The patent performs the computationally intensive Morton code calculation and nearest neighbor identification in advance during the encoding process. The results are stored in lookup tables or pre-computed data structures, so that during decoding the process simply involves retrieving pre-computed values, dramatically reducing real-time computational requirements while maintaining optimal prediction accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent segments the point cloud processing into distinct phases: encoding phase where nearest neighbor relationships are established and Morton codes are computed, and decoding phase where these pre-computed relationships are utilized. This temporal segmentation allows heavy computation to be performed when data is available (encoding time) rather than during real-time processing (decoding time).

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS20260032236A1Encoding method, decoding method, encoder, decoder, bitstream and storage medium
Publication Date: 2026.01.29 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD
  • US20260032236A1 patent drawing
  • US20260032236A1 patent drawing
  • US20260032236A1 patent drawing

AI summary

Provided are an encoding method and a decoding method. Regarding a node to be processed in a LOD M in a current frame, a codec can determine a reference point from a prediction point set of a reference frame for the current frame according to first Morton code information corresponding to the node to be processed, M being an integer greater than 1, and an index of a point in the prediction point set of the reference frame being determined based on Morton code information of the point; determine a search range based on second Morton code information corresponding to the reference point, and determine a nearest neighbor node corresponding to the node to be processed according to the search range; and determine a predicted attribute value corresponding to the node to be processed on the basis of a reconstruction value of the nearest neighbor node.