Vehicle Sensor Calibration Using Portable Rangefinding Fixture
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Solution Overview
Problem
Current sensor calibration methods for vehicles require dedicated facilities and are cumbersome, especially for aftermarket sensors, as they necessitate locking the vehicle in place, which limits flexibility and increases the footprint needed for calibration.
Innovation Solution
A portable fixture with rangefinding devices is used to measure angles and distances to known points on the vehicle, allowing for the determination of the target's position and orientation, enabling sensor calibration without the need for fixed facilities, and facilitating calibration in various positions and orientations around the vehicle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dedicated facilities with fixed targets are used for sensor calibration, then calibration precision can be ensured, but the footprint and complexity of the calibration system increases
Solution Approach 1:
The patent replaces the mechanical system of fixed physical calibration targets with an optical/electromagnetic system using projected patterns and image processing. The calibration target is no longer a large physical object but a virtual pattern projected onto a surface, eliminating the need for dedicated calibration facilities with fixed targets.
Solution Approach 2:
The patent creates a virtual copy of the calibration target through projection onto a surface rather than using a physical duplicate. The projected pattern serves as a lightweight representation of the calibration target, maintaining measurement precision while dramatically reducing the physical footprint required.
2Stability of the object's composition
If the vehicle is locked in place for calibration, then calibration stability is improved, but the ease of operation and flexibility decreases
Solution Approach 1:
Instead of locking the vehicle in place to achieve stability, the patent inverts the approach by making the calibration system adaptable to the vehicle's position. The system can calibrate sensors regardless of vehicle orientation or location by using the projected pattern and image processing to establish reference frames.
Solution Approach 2:
The patent introduces dynamics to the calibration process by allowing the vehicle to remain mobile and the calibration system to adapt to different positions and orientations. The projected calibration pattern and image processing algorithms dynamically adjust to maintain calibration accuracy without requiring the vehicle to be fixed in place.
3Measurement precision
If dedicated calibration facilities are used, then calibration accuracy is maintained, but the device complexity and cost increases
Solution Approach 1:
The patent replaces complex mechanical calibration facilities with a simpler optical projection system and image processing workflow. Instead of requiring precision-engineered physical calibration targets and fixed mounting structures, the system uses projected patterns that can be generated and processed through software.
Solution Approach 2:
The calibration system performs self-alignment and self-calibration through image processing of the projected pattern. The system automatically detects feature points on the projected pattern and calculates calibration parameters without requiring complex external equipment or manual alignment procedures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method allows for efficient and flexible sensor calibration with a reduced footprint, making it suitable for aftermarket sensors and repairs, as the fixture can be used in different locations and positions, simplifying the process and reducing the space required for calibration.
Implementation Method 1
The fixture includes a first rangefinding device and a second rangefinding device spaced from the first rangefinding device
Data Source
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AI summary
A method includes providing a fixture including a target in a field of view of a sensor mounted to a vehicle. The target is detectable by the sensor. The fixture includes a first rangefinding device and a second rangefinding device spaced from the first rangefinding device. The method includes measuring a first angle and first distance from the first rangefinding device to a first known point on the vehicle; measuring a second angle and second distance from the second rangefinding device to a second known point on the vehicle; determining a position and orientation of the target in a coordinate system relative to the vehicle based on the first angle, the first distance, the second angle, and the second distance; and calibrating the sensor based on the position and orientation of the target.