Reflectance Map Construction via Global Pose Optimization

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Solution Overview

Problem

Current methods for constructing reflectance maps in navigation systems, which rely on GPS and inertial navigation devices, suffer from errors due to satellite signal shifts and error accumulation, leading to reduced precision in positioning vehicles.

Innovation Solution

A method and apparatus that select key frame laser point clouds, perform global pose optimization on non-optimal key frames, and construct reflectance maps using the optimized positions and Euler angles of laser radar centers, improving the accuracy of coordinates in the world coordinate system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If GPS and inertial navigation devices are used to provide position and Euler angle data for laser point cloud construction, then the reflectance map can be constructed using available navigation data, but the positioning precision deteriorates due to satellite signal shifts and error accumulation

Engineering Contradiction:
Improvepositioning precisionVSAvoidnavigation data reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent implements a feedback mechanism by comparing the position and Euler angle data from GPS/inertial navigation devices with the actual laser point cloud data. The system calculates adjustment amounts based on the differences between expected and actual laser point cloud positions, and uses this feedback to optimize the navigation data, thereby improving positioning precision while maintaining the use of available navigation devices.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the parameters of the position and Euler angle data by applying optimization adjustments. The system modifies the navigation data parameters based on the adjustment amounts calculated from laser point cloud comparisons, transforming the original imprecise navigation data into optimized parameters that achieve higher positioning precision.

Inventive Principle:
Principle #35Parameter changes

2Area of stationary object

If all laser point clouds are used for reflectance map construction without selection, then the map coverage is complete, but the processing complexity and computational time increase significantly

Engineering Contradiction:
Improvemap coverage areaVSAvoidprocessing complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent segments the laser point clouds into different categories: key frame laser point clouds (selected based on specific criteria) and non-key frame laser point clouds. This segmentation allows the system to process only the essential key frame data for optimization while still using all data for comprehensive map construction, thereby reducing processing complexity while maintaining complete map coverage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by selecting only key frame laser point clouds for the optimization process rather than processing all laser point clouds. This partial processing approach reduces computational complexity while the final reflectance map construction still utilizes comprehensive data to ensure complete area coverage.

Inventive Principle:
Principle #16Partial or excessive action

3Measurement precision

If key frame laser point clouds are selected and optimized to improve positioning accuracy, then the reflectance map precision improves, but the algorithm complexity and computational requirements increase

Engineering Contradiction:
Improvereflectance map precisionVSAvoidalgorithm complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the laser point cloud data into key frame and non-key frame subsets, applying optimization only to the key frame data. This segmentation strategy reduces algorithm complexity by limiting the optimization scope to essential frames while still achieving improved reflectance map precision through the optimized key frame positions and Euler angles.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS10627520B2Method and apparatus for constructing reflectance map
Publication Date: 2020.04.21 APOLLO INTELLIGENT DRIVING (BEIJING) TECHNOLOGY CO LTD
  • US10627520B2 patent drawing
  • US10627520B2 patent drawing
  • US10627520B2 patent drawing

AI summary

A specific implementation of the method includes: constructing a reflectance map based on a position and an Euler angle, obtained through a global pose optimization and used for constructing a reflectance map, of a center of a laser radar corresponding to each frame laser point cloud used for constructing the reflectance map. This implementation implements the level-by-level pose optimization of key frame laser point clouds, sample frame laser point clouds, regular frame laser point clouds selected from laser point clouds used for constructing a reflectance map, to obtain an accurate position and Euler angle, used for constructing the reflectance map, of a center of the laser radar corresponding to each frame laser point cloud used for constructing the reflectance map, so that accurate coordinates of laser points in each frame laser point cloud used for constructing the reflectance map in a world coordinate system can be obtained.