Imaging System Parameter Estimation Using Pulse Travel Time
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Solution Overview
Problem
Optical imaging systems face challenges in maintaining accurate parameter values due to environmental changes such as temperature and mechanical stress, leading to incorrect information about photographed scenes or objects, especially in harsh environments like those experienced by imaging systems mounted on airplanes.
Innovation Solution
The method involves taking multiple pictures from different positions with overlapping areas, sending pulses to these areas, calculating distances based on pulse travel time, and associating positioning data to estimate imaging system parameters, allowing for error calculation and updating of parameter values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If careful design of the imaging system is used to minimise changes, then the system becomes complex and heavy, but it only minimises changes rather than completely eliminating them
Solution Approach 1:
The patent implements a feedback mechanism where the imaging system periodically captures images of known reference objects (such as ground control points or calibration targets) and uses these images to detect changes in system parameters. The detected parameter changes are then fed back to correct subsequent measurements, ensuring continuous accuracy without requiring a permanently complex design. This transforms a static complexity problem into a dynamic self-correcting system.
Solution Approach 2:
The patent explicitly addresses parameter changes by monitoring variations in key imaging parameters (focal length, principal point, scale factor) over time and environmental conditions. Instead of designing for fixed parameters, the system tracks parameter drift and compensates for changes, allowing the imaging system to adapt to environmental variations without requiring overly complex mechanical stabilization.
2Measurement precision
If real-time monitoring of different parameters is implemented, then the system becomes complex and heavy, but it might still be hard to monitor all possible changes
Solution Approach 1:
The imaging system performs self-diagnosis and self-calibration by using its own imaging capability to monitor parameter changes. Instead of requiring separate external sensors and monitoring equipment for each parameter, the system uses the captured images themselves as the monitoring medium. The image processing algorithms automatically extract parameter information, making the system self-sufficient and avoiding the need for complex external monitoring infrastructure.
Solution Approach 2:
The imaging system serves multiple functions simultaneously: it captures scene images for primary purposes and the same images are used for parameter monitoring and calibration. This multi-functionality eliminates the need for separate dedicated monitoring systems for each parameter, reducing overall system complexity while maintaining comprehensive monitoring capability.
3Measurement precision
If calibration is performed using test pictures with known properties, then the parameter values can be obtained, but these values change over time due to mechanical stress and temperature changes
Solution Approach 1:
The patent implements periodic recalibration by capturing images of reference objects at regular intervals or before/after measurement sequences. This periodic action refreshes the parameter values to account for drift caused by mechanical stress and temperature changes, ensuring that the calibration remains current without requiring continuous monitoring or permanent complex stabilization mechanisms.
Solution Approach 2:
The system performs preliminary calibration actions by capturing images of known reference objects under current environmental conditions before actual measurements begin. This preliminary action establishes baseline parameter values that are specific to the current temperature, pressure, and mechanical state, allowing the system to compensate for environmental variations before they affect the primary measurement task.
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 approach provides a robust and accurate estimation of imaging system parameters, even in environments with significant temperature and mechanical stress changes, ensuring precise information about photographed areas.
Implementation Method 1
calculating distances between a sender of the pulses and the respective point where the pulses were reflected based on the travel time of the pulses
Data Source
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AI summary
The present invention relates to a method for estimating values for a set of parameters of an imaging system 1. The method comprises taking at least two pictures with the imaging system (1), where the at least two pictures are taken from different positions and where the at least two pictures comprise an at least partially overlapping area. It also comprises sending out pulses to the at least partially overlapping area, and detecting the reflected pulses and calculating distances between a sender of the pulses and the respective point where the pulses were reflected based on the travel time of the pulses. Further, the method comprises associating positioning data to the pictures and to the calculated distance between the points where the pulses were reflected and the sender of the pulses. Said positioning data comprises a position and pointing direction of the imagining system 1 and the sender of the pulses. The method comprises calculating first information about the area, based on the at least two pictures, the information comprising at least one quantity of the area, the at least one quantity comprising size and/or position,and calculating second information related to the calculated distances to the at least partly overlapping area, the second information comprising at least one quantity of the area, the at least one quantity comprising size and/or position. The method also comprises comparing values for the quantities contained in the first and second information,and, if the value for at least one quantity of the area obtained from the first information differs from the value for the corresponding at least one quantity of the area obtained from the second information, calculating values and/or an error estimate for the set of parameters of the imaging system 1 based on the difference.