Active Optical Sensor Pitch Angle Calibration From Roadway Scan Points
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Solution Overview
Problem
Existing active optical sensor systems on vehicles require a previously recorded reference point cloud for calibration, which limits accuracy and is inconvenient due to the need for advance data collection.
Innovation Solution
Generate two subsets of scanning points from the roadway using the sensor system, determine a connection vector between points, and project it into the sensor's transmission plane parallel to its longitudinal axis to calculate the pitch angle position without relying on pre-recorded reference data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a previously recorded reference point cloud is used for calibration, then the alignment of the laser scanner can be corrected, but the accuracy is limited by the number of available measurement points and the calibration cannot be performed continuously
Solution Approach 1:
The sensor system uses the roadway itself as a reference object, eliminating the need for externally recorded reference point clouds. The system performs self-calibration by continuously comparing measurements against the known geometric properties of the roadway, enabling continuous calibration without requiring pre-recorded reference data or external calibration equipment.
Solution Approach 2:
The method pre-identifies characteristic points on the roadway (such as intersections, curves, or specific geometric features) that can serve as reference markers. These pre-identified points are then used during continuous operation to maintain alignment accuracy without requiring real-time reference data collection.
2Ease of manufacture
If reference measurement points are collected in advance, then calibration can be performed, but the process becomes inconvenient and the number of available measurement points is limited
Solution Approach 1:
The roadway serves multiple functions: it is both the environment in which the vehicle operates and the reference object for calibration. This eliminates the need for separate calibration procedures and reference data collection, as the same roadway provides continuous calibration opportunities during normal operation.
Solution Approach 2:
The system continuously generates and processes measurement points during normal vehicle operation, eliminating the need for separate reference data collection phases. The calibration process is integrated into the normal operation, allowing the system to serve itself by using operational data for calibration purposes.
3Reliability
If the sensor system is calibrated using a reference point cloud, then orientation deviations can be compensated, but the accuracy depends on the quality and availability of reference data
Solution Approach 1:
The system continuously compares the measured pitch angle against the known geometric properties of the roadway and adjusts the alignment accordingly. This feedback mechanism ensures that orientation compensation is continuously optimized based on actual operational conditions rather than relying on static pre-recorded reference data.
Solution Approach 2:
The calibration system transitions from a static, pre-recorded reference approach to a dynamic, continuous calibration process. The pitch angle determination is continuously updated during vehicle operation, allowing the system to adapt to changing conditions and maintain high accuracy throughout the vehicle's operational life.
Data Source
AI summary
According to a method for determining a pitch angle position of an active optical sensor system (2), which is mounted on a motor vehicle (1), a scatter plot (6) is generated by means of the sensor system (2). The scatter plot (6) includes a first and a second subset (7a, 7b) of scan points of the roadway (13). A first pair (A, B) of scan points is identified by means of a computing unit, wherein a point (A) is part of the first subset (7a), a further point (B) is part of the second subset (7b), and a projection (14′) of a first connection vector (14) of the first pair (A, B) is in a transmission plane parallel to a longitudinal axis of the sensor system (2). A first angle (δ) which encloses the first connection vector (14) with the longitudinal axis (15) of the sensor system (2) is determined by means of the computing unit (4).