Mono Camera Intrinsic Recalibration Under Thermal Distortion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing visual tracking systems face challenges in accurately calibrating camera intrinsic parameters due to thermal distortions caused by heat generated by cameras and other components, which are not addressed by factory calibration methods.
Innovation Solution
A method for recalibrating camera intrinsic parameters by detecting thermal changes and generating a temperature-based distortion model, involving a series of interactive operations to align feature points between the central and border regions of the camera lens, using a visual-inertial tracking system to adjust and correct detected features based on temperature-specific intrinsic parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If factory calibration is used, then initial calibration is provided, but calibration accuracy deteriorates under varying thermal conditions
Solution Approach 1:
The system dynamically adjusts camera intrinsic parameters based on real-time temperature readings. A temperature sensor continuously monitors thermal conditions, and the calibration parameters are updated according to the current temperature to maintain accuracy under varying thermal conditions.
Solution Approach 2:
The patent changes the calibration parameters based on temperature variations. Different temperature ranges correspond to different sets of calibration parameters, allowing the system to adapt to thermal conditions by selecting appropriate parameters from a pre-characterized set.
2Measurement precision
If thermal distortion compensation is implemented, then calibration accuracy under thermal conditions improves, but system complexity increases
Solution Approach 1:
The system performs preliminary thermal characterization during factory calibration, creating a lookup table or characterization model that maps temperature to calibration parameters. This pre-computed data allows runtime compensation without requiring complex real-time calculations or additional hardware.
Solution Approach 2:
The patent introduces a temperature sensor as an intermediary that bridges the thermal environment and the calibration system. The sensor provides temperature readings that trigger appropriate calibration parameter selection, simplifying the compensation mechanism through this intermediate measurement device.
3Measurement precision
If interactive calibration operations are required, then calibration precision improves, but user operation time increases
Solution Approach 1:
The system applies different calibration strategies to different regions of the camera field of view. Border region features are used for thermal distortion compensation while central region features provide baseline calibration, allowing precise local adjustments without requiring complete recalibration of the entire system.
Solution Approach 2:
The patent performs calibration only on selected feature points in specific regions (border regions affected by thermal distortion) rather than requiring calibration of all features. This partial calibration approach reduces the number of interactive operations needed while maintaining precision where it matters most.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method for adjusting camera intrinsic parameters of a single camera visual tracking device is described. In one aspect, a method includes accessing a temperature of a camera of the visual tracking system, detecting that the temperature of the camera exceeds a threshold, in response identifying one or more feature points that are located in a central region of an initial image, generating a graphical user interface element that instructs a user of the visual tracking system to move the visual tracking system towards a border region of the initial image, and determining intrinsic parameters of the camera based on matching pairs of the one or more detected feature points in the border region and one or more projected feature points in the border region.