3D Surfel Maps with Semantic Labels for Autonomous Vehicle Localization

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Solution Overview

Problem

Autonomous vehicles face challenges in interpreting real-time sensor data and navigating environments due to limitations in existing map representations, which are either 2.5-dimensional and unreliable or rely solely on offline sensor data, leading to inefficiencies and inaccuracies in vehicle localization, sensor calibration, and object detection.

Innovation Solution

The use of a three-dimensional surfel map with semantic labels that combines existing surfel data and real-time sensor data, allowing for improved vehicle localization, sensor calibration, and object detection by assigning uncertainty to both data types and leveraging semantic information to enhance the accuracy of environmental predictions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a 2.5-dimensional map representation is used, then the system complexity is reduced, but the measurement precision and reliability of environmental representation deteriorate

Engineering Contradiction:
Improvemap representation complexityVSAvoidenvironmental representation accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent transitions from 2.5-dimensional map representations to full 3-dimensional surfel maps. Each surfel is defined by position (x, y, z) and orientation (normal vector), enabling accurate representation of objects at different altitudes and orientations. This dimensional enhancement resolves the contradiction by providing complete spatial information without excessive complexity, as surfels are computationally efficient primitives.

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

Solution Approach 2:

The patent introduces semantic labels as additional parameters associated with each surfel. These labels provide information about object characteristics, materials, and properties, transforming the map from a purely geometric representation to a semantically enriched one. This parameter enhancement improves measurement precision and reliability while maintaining computational tractability.

Inventive Principle:
Principle #35Parameter changes

2Loss of time

If offline sensor data is used exclusively, then the loss of time for real-time processing is reduced, but the reliability of environmental state representation deteriorates due to environmental changes

Engineering Contradiction:
Improvereal-time processing timeVSAvoidenvironmental state accuracy
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The system pre-generates 3-D surfel maps from offline sensor data collected by multiple vehicles, storing semantic labels and environmental features in advance. This preliminary action creates a rich prior knowledge base that can be quickly queried during real-time operation, reducing processing time while maintaining reliability through the use of pre-validated environmental information.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously updates the 3-D surfel map by comparing real-time sensor data with the stored map representation. Discrepancies trigger map updates, creating a feedback loop that maintains reliability. The semantic labels guide this update process by identifying which environmental features are most critical to maintain accuracy for, ensuring that time-consuming updates focus on the most important changes.

Inventive Principle:
Principle #23Feedback

3Reliability

If real-time sensor data is used exclusively, then the reliability of current environmental state is improved, but the productivity and efficiency of navigation decisions deteriorates due to lack of contextual knowledge

Engineering Contradiction:
Improvecurrent environmental state accuracyVSAvoidnavigation decision efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system pre-computes surfel maps with semantic labels that encode contextual knowledge about the environment, such as object types, materials, and expected properties. This preliminary processing of contextual information allows the vehicle to make faster navigation decisions by querying pre-analyzed environmental data rather than processing all raw sensor data in real-time, thus improving productivity without sacrificing reliability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The 3-D surfel map with semantic labels acts as an intermediary between raw real-time sensor data and navigation decision-making. The surfels provide a structured, semantically-enriched representation that bridges the gap between noisy sensor inputs and high-level planning algorithms, improving both reliability and productivity by filtering and organizing information before it reaches the decision-making system.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Measurement precision

If semantic labels are added to surfel data, then the measurement precision of object characteristics is improved, but the device complexity increases

Engineering Contradiction:
Improveobject characteristic accuracyVSAvoiddata structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments environmental information into discrete surfel units, each with its own semantic labels. This segmentation allows the system to manage complexity by processing only relevant surfels and their labels rather than handling all environmental data uniformly. The modular surfel structure enables efficient storage and query operations, offsetting the complexity introduced by semantic labels through improved data organization.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS11915490B2Annotated surfel maps
Publication Date: 2024.02.27 WAYMO LLC
  • US11915490B2 patent drawing
  • US11915490B2 patent drawing
  • US11915490B2 patent drawing

AI summary

Methods, systems, and apparatus, including computer programs encoded on computer storage media, for the generation and use of a surfel map with semantic labels. One of the methods includes receiving a surfel map that includes a plurality of surfels, wherein each surfel has associated data that includes one or more semantic labels; obtaining sensor data for one or more locations in the environment, the sensor data having been captured by one or more sensors of a first vehicle; determining one or more surfels corresponding to the one or more locations of the obtained sensor data; identifying one or more semantic labels for the one or more surfels corresponding to the one or more locations of the obtained sensor data; and performing, for each surfel corresponding to the one or more locations of the obtained sensor data, a label-specific detection process for the surfel.