Point Cloud Map Registration for Globally Consistent HD Mapping

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Solution Overview

Problem

Current high-definition map creation methods for autonomous driving face challenges in ensuring global consistency and efficiency during the reconstruction of large areas, such as cities or countries, due to the complexity of aligning and splicing point cloud data from various sources.

Innovation Solution

A method involving the collection of point cloud data using LiDAR, GPS, and IMU, followed by association and registration of frames to create a consistent point cloud relation graph, which is then used to determine relative poses and splice the data into a high-definition map, utilizing techniques like Maximum A Posteriori estimation and distributed parallelization to improve data processing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If point cloud data is collected and divided into blocks for high-definition map creation, then the map coverage area increases, but the consistency and alignment quality deteriorates

Engineering Contradiction:
Improvemap coverage areaVSAvoidblock alignment quality
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent divides the large-scale point cloud data into multiple blocks for parallel processing, which enables the system to handle large coverage areas efficiently. The segmentation is performed in a way that maintains the necessary spatial relationships between adjacent blocks, allowing for subsequent consistent alignment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a global pose graph as an intermediary structure that connects all local block alignments. This pose graph serves as a mediator that ensures global consistency across all blocks by optimizing the relative poses between them, thereby maintaining alignment quality even as the coverage area expands.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If point cloud registration is performed to ensure global consistency, then the map quality improves, but the processing time increases

Engineering Contradiction:
Improvemap qualityVSAvoidprocessing time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The registration process is segmented into local and global stages. Local registration is performed independently on each block to establish initial alignment, while global registration optimizes the pose graph connecting all blocks. This segmentation allows parallel processing of local registrations, significantly reducing overall processing time while maintaining global consistency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary local registration on each block before conducting global optimization. This preliminary action establishes a good initial alignment that reduces the computational burden of the subsequent global optimization, thereby decreasing total processing time while ensuring final map quality.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If distributed parallelization is used for data processing, then the creation efficiency improves, but the system complexity increases

Engineering Contradiction:
Improvecreation efficiencyVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system is segmented into independent processing units that can operate in parallel on different blocks of point cloud data. Each unit handles a specific block independently, which simplifies the implementation of parallelization while improving creation efficiency. The segmented approach naturally divides the complex task into manageable, parallelizable components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges the results from multiple parallel processing units through the global pose graph optimization. This merging step consolidates the independently processed blocks into a consistent global map, managing system complexity by providing a unified framework that integrates parallel outputs without requiring complex inter-unit communication during processing.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4116935B1High-definition map creation method and device, and electronic device
Publication Date: 2024.05.08 BEIJING BAIDU NETCOM SCI & TECH CO LTD
  • EP4116935B1 patent drawingFigure 1~2
  • EP4116935B1 patent drawingFigure 3~4
  • EP4116935B1 patent drawingFigure 5

AI summary

A high-definition map creation method includes: obtaining point cloud data collected with respect to a target region, the point cloud data including K frames of point clouds and an initial pose of each frame of point cloud, K being an integer greater than 1; associating the K frames of point clouds with each other in accordance with the initial pose to obtain a first point cloud relation graph of the K frames of point clouds; performing point cloud registration on the K frames of point clouds in accordance with the first point cloud relation graph and the initial pose to obtain a target relative pose of each frame of point cloud in the K frames of point clouds; and splicing the K frames of point clouds in accordance with the target relative pose to obtain a point cloud map of the target region.