In-Vehicle Camera Calibration Timing for Thermal Optical Axis Shift
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Solution Overview
Problem
Existing image processing technologies fail to adequately address the issue of optical axis shift during temperature changes in in-vehicle stereo cameras, leading to errors in distance measurement and adversely affecting vehicle control systems.
Innovation Solution
The proposed solution involves an in-vehicle image processing device that integrates a temperature sensor, a temperature prediction unit, and a calibration timing determination unit to predict future optical axis shifts and adjust the calibration process accordingly. The device includes a temperature sensor that detects a current temperature, a temperature prediction unit that predicts a future temperature, and a calibration timing determination unit that determines whether to start calibration based on vehicle operation information or external recognition information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibration using image processing technology is performed to correct optical axis shift, then distance measurement accuracy is improved, but the ADAS must be stopped during calibration causing loss of time
Solution Approach 1:
The system performs calibration in advance during periods when the ADAS is not actively requiring high-precision distance measurements. By predicting future temperature changes and planning calibration timing beforehand, the system prepares correction data when conditions permit, thus avoiding interruptions to critical ADAS operations while still maintaining measurement accuracy.
Solution Approach 2:
The system continuously monitors temperature changes and their impact on optical axis position, using this feedback to determine optimal calibration timing. By measuring temperature trends and their correlation with optical axis shift, the system can predict when calibration will be most effective and schedule it accordingly, minimizing disruption to ADAS functionality while maintaining precision.
2Measurement precision
If calibration is performed frequently to maintain accuracy under temperature changes, then distance measurement precision is improved, but system complexity and processing overhead increase
Solution Approach 1:
The system changes the parameter being calibrated from direct optical axis position to temperature-based prediction parameters. By establishing the relationship between temperature changes and optical axis shift, the system can calculate correction values based on temperature measurements alone, simplifying the calibration process while maintaining accuracy under varying thermal conditions.
Solution Approach 2:
Temperature serves as an intermediary parameter that links environmental conditions to optical axis position changes. Instead of directly measuring and correcting optical axis shift, the system uses temperature as a mediator to predict and compensate for positional changes, reducing the complexity of direct optical measurements while maintaining correction effectiveness.
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 solution effectively suppresses the stop period of the ADAS by optimizing the execution timing of calibration, thereby maintaining accurate distance measurements and reducing the need for frequent recalibration.
Implementation Method 1
a temperature sensor that detects a current temperature
Implementation Method 2
a structure such as a lens, a substrate, and a housing is thermally deformed, so that an optical axis shift of the lens occurs with the thermal deformation
Data Source
AI summary
The execution timing of calibration is optimized, and the stop period of an ADAS is suppressed. An in-vehicle image processing device that is mounted on a vehicle and processes an external image acquired by a camera, the in-vehicle image processing device includes a temperature sensor that detects a current temperature, a temperature prediction unit that predicts a future temperature based on time-series data of the temperature, a distance measurement error prediction unit that predicts a future distance measurement error based on a prediction of the temperature, a calibration timing determination unit that determines whether calibration using the image is executable based on vehicle operation information or external recognition information, and a calibration start determination unit that determines whether to start calibration using the image based on the current temperature or a remaining time in a case where the calibration timing determination unit determines that the calibration is executable during the remaining time until a time at which a distance measurement error predicted by the distance measurement error prediction unit is predicted to exceed a threshold.