Point Cloud Depth Encoding via Occupancy Map Segmentation

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Solution Overview

Problem

Existing technologies face challenges in efficiently compressing and distributing dynamic point clouds while maintaining acceptable quality and minimizing bit-rate consumption.

Innovation Solution

A method involving the assignment of pixel values in an occupancy image to indicate either the storage of depth values in a depth image or the use of a fixed-length codeword representing depth values, along with signaling information about the use of fixed-length codewords and their length.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If depth values are stored for all 3D samples in a depth image, then quality of point cloud representation is improved, but bit-rate consumption increases

Engineering Contradiction:
Improvequality of point cloud representationVSAvoidbit-rate consumption
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts only the necessary depth information by using an occupancy map to identify which 3D sample positions actually contain points. Instead of storing depth values for all possible positions, only the occupied positions are encoded in the depth image, removing redundant data and reducing bit-rate while maintaining quality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs dynamic encoding strategies where the occupancy map is updated based on the actual distribution of 3D samples. The encoding process adapts to the dynamic characteristics of the point cloud data, adjusting which positions require depth storage based on real-time occupancy information.

Inventive Principle:
Principle #15Dynamics

2Quantity of substance

If compression is increased to reduce bit-rate, then bit-rate consumption is improved, but quality of point cloud representation deteriorates

Engineering Contradiction:
Improvebit-rate consumptionVSAvoidquality of point cloud representation
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent segments the point cloud data processing into two distinct stages: first generating an occupancy map that identifies occupied positions, then creating a depth image only for those occupied positions. This segmentation allows efficient compression by eliminating unused space while preserving all necessary quality information.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The occupancy map serves as an intermediary data structure that bridges the gap between the 3D sample positions and the depth image. It acts as a guide to determine which positions require depth encoding, enabling lossless compression by preventing encoding of empty positions while ensuring all occupied positions are properly represented.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If variable-length codewords are used for depth values, then coding efficiency is improved, but device complexity increases

Engineering Contradiction:
Improvecoding efficiencyVSAvoidencoding/decoding complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent performs preliminary encoding by first creating the occupancy map before generating the depth image. This preliminary action identifies all positions that require encoding, allowing the system to use simple fixed-length codewords for those specific positions rather than implementing complex variable-length encoding logic throughout the entire process.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS20250029284A1Processing missing points of a point cloud
Publication Date: 2025.01.23 INTERDIGITAL VC HOLDINGS INC
  • US20250029284A1 patent drawing
  • US20250029284A1 patent drawing
  • US20250029284A1 patent drawing

AI summary

At least one embodiment relates to a method assigning a pixel value of an occupancy map either indicates that a depth value of at least one 3D sample of a point cloud frame projected along a same projection line is stored as a pixel value of at least one layer or equals a fixed-length codeword representing a depth value of at least one 3D sample projection along said projection line.