Multi-Lane Road Geometry Estimation With Bayesian Hypothesis Tracking

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Solution Overview

Problem

Current road estimation systems for autonomous vehicles face challenges in accurately modeling complex road geometries, especially in scenarios with multiple lanes, on-ramps, and off-ramps, due to limitations in data association and clutter handling, which affects the reliability and redundancy of road feature detection.

Innovation Solution

A model-based algorithm using a Bayesian approach with a multiple hypothesis tracking filter that predicts road model hypotheses based on vehicle motion data and perception data from sensors, associating road features to estimate lane center curves and existence probabilities, and selecting the most probable road model for accurate road geometry estimation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a traditional road estimation system is used, then the system complexity is low, but the measurement precision of road geometry in complex environments deteriorates

Engineering Contradiction:
Improveroad geometry estimation accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The road model is segmented into multiple hypotheses, each representing a different possible road configuration. The tracking filter maintains multiple road model hypotheses simultaneously, allowing the system to evaluate different road geometry possibilities independently and select the most probable one, thereby improving measurement precision without overwhelming system complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The road estimation system dynamically adapts by continuously updating the probability of each road model hypothesis based on new sensor measurements and vehicle motion data. The system transitions between different road model hypotheses as the vehicle encounters complex road geometries, enabling accurate real-time estimation while maintaining manageable computational complexity through probabilistic filtering.

Inventive Principle:
Principle #15Dynamics

2Reliability

If multiple road model hypotheses are tracked, then the reliability of road estimation improves, but the device complexity increases

Engineering Contradiction:
Improveroad estimation reliabilityVSAvoidtracking filter complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system tracks multiple road model hypotheses beyond what a single deterministic model would provide, maintaining a set of probable road configurations with associated probabilities. This partial multiplicity approach improves reliability by considering alternative road geometries without fully enumerating all possible configurations, balancing reliability improvement with acceptable filter complexity.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The tracking filter incorporates feedback mechanisms where each new sensor measurement updates the probability distribution across multiple road model hypotheses. The system uses feedback from vehicle motion data and sensor associations to reinforce or eliminate hypotheses, improving reliability through continuous validation while managing complexity through probabilistic convergence.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If real-time road model updating is performed, then the adaptability to changing conditions improves, but the loss of time for computation increases

Engineering Contradiction:
Improveadaptation to changing road conditionsVSAvoidcomputation time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The system performs preliminary actions by pre-defining the structure of road model hypotheses and their associated probability distributions before actual road estimation is needed. The tracking filter is pre-configured with multiple possible road configurations, allowing real-time adaptation to changing conditions without the computational overhead of generating hypotheses on-the-fly, thus reducing computation time while maintaining high adaptability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system achieves real-time adaptability by changing parameters within the existing road model hypotheses rather than reconstructing entire models. The tracking filter adjusts probability distributions and geometric parameters of predefined hypotheses based on incoming sensor data, enabling rapid adaptation to changing road conditions while minimizing computation time through parameter optimization rather than full model regeneration.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4478304A1Model-based road estimation
Publication Date: 2024.12.18 ZENSEACT AB
  • EP4478304A1 patent drawingFigure 1~2(d)
  • EP4478304A1 patent drawingFigure 3a~3b
  • EP4478304A1 patent drawingFigure 4

AI summary

A computer-implemented method for estimating a road geometry of a road upon which a vehicle is traveling and related aspects are disclosed. The disclosed embodiments provide a model-based technique for estimating a road model having an arbitrary number of lanes on a road as well as any entrance lanes (i.e. on-ramp or slip roads) and exit lanes (i.e. off ramps or off-slip roads). In more detail, the herein disclosed embodiments utilize a Bayesian approach to multi-lane tracking in various traffic scenarios, such as e.g. highway scenarios. The employed model-based algorithm estimates the lane center curves of multi-lane roads based on vehicle motion data (e.g. speed, angular velocity) and perception data (e.g. camera output, lidar output, radar output, etc.) that comprises detected road features (e.g. lane markers, road edges, road barriers, guard rails, road markers, etc.) or other objects (e.g. other road users).