3D Submap and Global Map Alignment for Centimeter Precision Localization

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Solution Overview

Problem

Autonomous vehicles face challenges in robust and accurate localization in urban environments due to GPS signal unavailability and multi-path errors, leading to significant drift in visual/LiDAR SLAM methods and limited decimeter-level accuracy.

Innovation Solution

A method and system that aligns a 3D submap with a LiDAR-based global map by extracting and classifying features, establishing correspondence, and iteratively refining the location using camera and LiDAR data, achieving centimeter-level precision through voxelization and probabilistic modeling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If visual/LiDAR SLAM methods are used for localization, then GPS signal unavailability is addressed, but drift occurs and accuracy is limited to decimeter-level

Engineering Contradiction:
Improvelocalization reliabilityVSAvoidlocalization accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent divides the localization problem into two segments: visual SLAM for short-term tracking and map alignment for long-term accuracy. The submap is constructed from camera images using visual SLAM, then aligned with the pre-built LiDAR global map to correct drift and achieve centimeter-level precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges two different sensing modalities (visual camera data and LiDAR range data) into a unified localization system. The visual submap and LiDAR global map are registered through feature matching and coordinate transformation, combining the advantages of both sensing approaches.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If feature extraction and matching is performed to improve localization accuracy, then computational complexity increases

Engineering Contradiction:
Improvelocalization accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts features from specific local regions of interest in the submap and global map rather than processing the entire map uniformly. This localized feature extraction reduces computational load while maintaining accuracy in critical localization areas.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent performs preliminary feature extraction and classification before the actual alignment process. Features are pre-processed and organized into different categories, which simplifies the subsequent matching and correspondence establishment steps.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS10223807B1Feature extraction from 3D submap and global map system and method for centimeter precision localization using camera-based submap and lidar-based global map
Publication Date: 2019.03.05 CREATEAI INC
  • US10223807B1 patent drawing
  • US10223807B1 patent drawing
  • US10223807B1 patent drawing

AI summary

A method of localization for a non-transitory computer readable storage medium storing one or more programs is disclosed. The one or more programs comprise instructions, which when executed by a computing device, cause the computing device to perform utilizing one or more autonomous vehicle driving modules that execute processing of images from a camera and data from a LiDAR the following steps comprising: aligning a 3D submap with a global map; extracting features from the 3D submap and the global map; classifying the extracted features in classes; and establishing correspondence of features in a same class between the 3D submap and the global map.