Extrinsic Calibration for Camera and Range Sensor Fusion
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Solution Overview
Problem
Current extrinsic calibration methods for cameras and range sensors fail to achieve submillimeter accuracy at large standoff distances, which is necessary for high precision metrology applications.
Innovation Solution
A method involving multiple rotation positions of an emitter to collect ranging and imaging measurements, followed by processing to determine calibration parameters that estimate the relationship between the camera and ranging sensor, using statistics and outlier removal to achieve submillimeter accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current extrinsic calibration methods are used, then calibration can be performed, but accuracy remains at centimeter to millimeter order which is insufficient for high precision metrology at large standoff distances
Solution Approach 1:
The calibration process is segmented into multiple independent calibration steps, each producing a set of calibration parameters. By dividing the calibration into N separate measurements and processing them individually before aggregation, the method achieves higher precision at large standoff distances by treating each measurement segment as an independent calibration event that can be optimized separately.
Solution Approach 2:
The method performs more calibration measurements than the minimum required (N≥4 sets of calibration parameters), using excessive action to improve precision. By collecting and processing multiple sets of calibration parameters beyond the theoretical minimum, the system achieves submillimeter accuracy through statistical aggregation and outlier removal, exceeding the precision of conventional methods.
2Measurement precision
If multiple rotation positions and target locations are used to improve accuracy, then submillimeter calibration accuracy is achieved, but the calibration procedure becomes more complex
Solution Approach 1:
The method incorporates feedback through iterative outlier removal and statistical processing of calibration parameters. Each calibration step provides feedback that informs subsequent processing, with outliers identified and removed based on statistical criteria, and final calibration parameters refined through repeated processing until convergence or maximum iterations are reached.
Solution Approach 2:
The calibration procedure changes multiple parameters simultaneously including target locations, emitter rotation positions, and number of calibration steps. By systematically varying these parameters and processing the resulting sets of calibration parameters through statistical aggregation, the method achieves submillimeter accuracy while managing complexity through structured parameter variation.
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
The method enables submillimeter extrinsic calibration accuracy, allowing for precise fusion of imaging and ranging sensor data for high precision metrology and autonomous vehicle applications.
Implementation Method 1
transmitting, by the emitter at M number of the rotation positions, transmit signals to the target located at N number of the locations; generating, by the transmit signals reflecting off of the target, reflection signals; receiving, by the ranging sensor, the reflection signals
Data Source
AI summary
In one or more embodiments, a system for calibration between a camera and a ranging sensor comprises a ranging sensor to obtain ranging measurements for a target located at N number of locations with an emitter at M number of rotation positions. The system further comprises a camera to image the target to generate imaging measurements corresponding to the ranging measurements. Further, the system comprises a processor(s) to determine replacement ranging measurements that all lie in the same plane; to sample the replacement ranging measurements to produce sampled replacement ranging measurements; to determine sampled replacement imaging measurements corresponding to the sampled replacement ranging measurements; and to calculate calibration parameters by using some of the sampled replacement ranging measurements and the sampled replacement imaging measurements corresponding to the sampled replacement ranging measurements that are used, where the calibration parameters estimate the relationship of the camera to the ranging sensor.