Lidar Receiver Calibration Using Camera-Verified Reference Reflectivity
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Solution Overview
Problem
Existing lidar sensor calibration methods are inadequate for addressing manufacturing differences, aging, environmental conditions, and operational changes, leading to inconsistent object recognition and difficulty in fusing data from lidar and cameras.
Innovation Solution
A method involving laser radiation from a lidar sensor is applied to a reference object with predetermined reflectivity, and the sensitivity of the lidar receiver is calibrated based on the intensity of the reflected radiation, allowing recalibration during operation to compensate for environmental and aging effects, and aligning lidar and camera data for precise object recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lidar sensor calibration is performed using fixed factory settings, then initial manufacturing precision is achieved, but the sensor cannot compensate for aging, environmental conditions, and operational changes
Solution Approach 1:
The patent implements dynamic calibration by enabling the lidar sensor to automatically adjust its calibration parameters during operation based on real-time environmental conditions and operational state, transforming the static factory calibration into a dynamic adaptive process that maintains reliability across changing conditions
Solution Approach 2:
The patent employs feedback mechanisms where the lidar sensor continuously monitors its own performance and environmental conditions, then automatically adjusts calibration parameters based on this feedback, creating a closed-loop system that maintains calibration consistency despite aging and environmental changes
2Measurement precision
If lidar and camera systems use separate calibration methods, then each system maintains its own precision, but data fusion between the two systems becomes difficult
Solution Approach 1:
The patent merges the calibration processes of lidar and camera systems by establishing a unified calibration framework that uses common reference objects and coordinated calibration procedures, enabling both sensors to be calibrated simultaneously with shared parameters, thereby simplifying data fusion while maintaining individual precision
Solution Approach 2:
The patent creates a universal calibration approach where a single calibration process serves multiple functions: it calibrates both lidar and camera systems independently while also establishing the transformation relationships needed for data fusion, eliminating the need for separate calibration procedures
3Ease of manufacture
If manufacturing differences between lidar sensors are not compensated, then production complexity is reduced, but object recognition consistency varies across different units
Solution Approach 1:
The patent implements self-service calibration where each lidar sensor automatically performs its own calibration during operation using environmental reference objects, eliminating the need for complex factory calibration procedures and compensating for manufacturing differences through autonomous self-adjustment
Solution Approach 2:
The patent compensates for manufacturing differences by dynamically adjusting calibration parameters for each sensor based on its specific characteristics and operational conditions, allowing sensors with varying manufacturing tolerances to achieve consistent object recognition performance through parameter optimization
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
Ensures consistent object recognition and improved data fusion between lidar and camera systems by adapting sensitivity and transmission output, enabling reliable operation of automated vehicles or robots.
Implementation Method 1
Laser radiation reflected from the reference object is then received by a lidar receiver on the lidar sensor
Implementation Method 2
the control and interpretation electronics, using the impulse propagation time method applied to the time between sending and receiving a light pulse and based on the speed of light
Implementation Method 3
the sensitivity of the lidar receiver, a photo detector array, for example, is calibrated
Data Source
AI summary
A method for calibrating a lidar sensor of a vehicle or of a robot may include applying laser radiation of the lidar sensor to a reference object in a reference calibration process. The lidar sensor generates a sensor signal, which correlates to the laser radiation and has a reference intensity, and a sensitivity of the lidar receiver being calibrated according to the reference intensity. At least one camera is used to detect whether at least one object having reflectivity corresponding to that of a reference object of the reference calibration process is present in the detection range of the lidar sensor. An intensity of a sensor signal generated on the basis of laser radiation reflected by the object is determined, the determined intensity being compared with an associated reference intensity and the sensitivity of the lidar receiver being calibrated according to the comparison of the intensity with the reference intensity.