LiDAR Point Cloud Classification Using 3D Grid Maps

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Solution Overview

Problem

Existing obstacle identification methods for autonomous vehicles using lidar-based laser point cloud data are either rule-based, which is difficult to implement for all types of obstacles, or machine learning-based, which struggles with untrained obstacles, leading to inefficiencies in obstacle recognition.

Innovation Solution

A method and apparatus that acquire current pose information of an autonomous vehicle to identify laser point cloud data by utilizing a preset three-dimensional grid map, where N×N map blocks are loaded into a cache, and each laser point data is classified as static or dynamic based on corresponding grid cube types, improving the accuracy of obstacle identification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If rule-based methods are used for obstacle identification, then the implementation is straightforward for known obstacle types, but it is difficult to identify all types of obstacles in the real world

Engineering Contradiction:
Improveease of implementationVSAvoididentifiable obstacle types
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent segments the continuous laser point cloud data into discrete grid cubes within a three-dimensional grid map. Each grid cube is independently classified as static or dynamic, enabling systematic processing of obstacle identification while maintaining the ability to handle diverse obstacle types through structured spatial division.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from two-dimensional map blocks to three-dimensional grid cubes by adding the vertical dimension. This dimensional expansion allows the system to capture and classify obstacles at different heights, significantly improving adaptability to various obstacle types while maintaining manageable complexity through systematic spatial organization.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If machine learning-based methods are used for obstacle identification, then the system can learn from training data, but it cannot identify types of obstacles that have not been trained

Engineering Contradiction:
Improveidentification accuracyVSAvoiduntrained obstacle recognition
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal obstacle identification framework where grid cubes serve as a common representation for all obstacle types. The static/dynamic classification system provides a multi-functional approach that can handle any obstacle type without requiring specific training, as the system universally applies the same spatial classification logic to all detected objects.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the classification parameters from specific obstacle type labels to fundamental spatial properties (static vs. dynamic). This parameter transformation allows the system to maintain high identification accuracy while achieving universal adaptability, as any obstacle can be classified by its motion characteristics rather than requiring pre-trained type-specific models.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If a large portion of the three-dimensional grid map is loaded into cache, then the obstacle identification accuracy improves, but the memory consumption increases

Engineering Contradiction:
Improveobstacle identification accuracyVSAvoidmemory consumption
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent applies local quality by loading only N×N map blocks surrounding the current vehicle position into cache, rather than the entire map. This localized approach ensures high obstacle identification accuracy in the relevant area while significantly reducing memory consumption by excluding distant, irrelevant map regions from the cache.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent performs preliminary loading of the N×N map blocks into cache before obstacle identification is needed. This advance preparation ensures that the required spatial data is readily available in memory when identification is performed, improving accuracy without requiring the entire map to be permanently loaded, thus optimizing memory usage.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS11131999B2Method and apparatus for identifying laser point cloud data of autonomous vehicle
Publication Date: 2021.09.28 APOLLO INTELLIGENT DRIVING (BEIJING) TECHNOLOGY CO LTD
  • US11131999B2 patent drawing
  • US11131999B2 patent drawing
  • US11131999B2 patent drawing

AI summary

A method and apparatus for identifying laser point cloud data of an autonomous vehicle provided with a lidar. A specific implementation of the method includes: acquiring current pose information of the autonomous vehicle in a world coordinate system in response to receiving a latest frame of laser point cloud data collected by the lidar; acquiring from the cache, based on the current pose information, N×N map blocks centered on map blocks corresponding to the current pose information in a preset three-dimensional grid map and pre-loaded into a cache and are; and executing, for each laser point data in the received laser point cloud data, the laser point data identification operations. The implementation realizes identifying whether each laser point data is a static laser point, and can improve the accuracy rate of identifying a laser point data obstacle.