Camera Calibration Using Mobile Robot Trajectories for Subject Tracking
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Solution Overview
Problem
Existing camera systems in warehouses and industrial facilities are not calibrated for advanced purposes like determining or tracking subject positions, requiring manual calibration which is inconvenient and expensive, and separate systems for surveillance and position tracking increase costs and failure risks.
Innovation Solution
A method for calibrating cameras using a mobile robot within a predefined coordinate system, optimizing camera parameters by minimizing reprojection errors, allowing the camera to be used for advanced purposes such as determining and tracking subject positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If manual calibration is performed on existing camera systems, then the camera can be used for advanced purposes like determining and tracking subject positions, but the process is inconvenient and expensive
Solution Approach 1:
The calibration system automatically performs calibration without requiring manual intervention. The mobile robot executes predefined trajectories and the system autonomously optimizes camera parameters by minimizing reprojection errors, eliminating the need for manual calibration operations while enabling advanced camera functionality
Solution Approach 2:
The calibration process is performed in advance before the camera is put into service for advanced purposes. By pre-calibrating the camera using the mobile robot in predefined trajectories, the system prepares the camera parameters beforehand, making subsequent operations convenient and eliminating the need for manual calibration during actual use
2Adaptability or versatility
If separate systems are provided for surveillance and position tracking, then both functions can be performed, but the cost and failure risk increase
Solution Approach 1:
The camera system is designed to perform multiple functions: surveillance/monitoring and advanced position tracking/localization. By calibrating the camera using the mobile robot with known position data, the same camera infrastructure can serve both surveillance purposes and scientific measurement purposes, eliminating the need for separate dedicated systems
Solution Approach 2:
The patent combines the surveillance camera system with the position tracking system into a single integrated system. The calibrated camera serves dual purposes, merging what were previously separate systems (surveillance and motion capture) into one unified infrastructure, thereby reducing complexity and cost
3Adaptability or versatility
If existing camera systems are used for advanced purposes, then additional value is unlocked from low-cost systems, but the camera parameters must be optimized through minimization of reprojection errors
Solution Approach 1:
The calibration process uses feedback from the mobile robot's known position data to optimize camera parameters. The system calculates reprojection errors by comparing expected and actual image locations, and uses this feedback to iteratively refine camera parameter estimates, ensuring high precision without requiring expensive hardware
Data Source
AI summary
A method for calibrating a camera which is in a position and orientation within a predefined coordinate system. The method includes the steps of, (a) moving an object along a trajectory within the predefined coordinate system and within a field of view of the camera; (b) determining the physical location of the object, over time, within the predefined coordinate system; (c) capturing one or more images of the object using the camera as the object is moving along the trajectory; (d) recording the time instant at which each of the respective one or more images are captured; (e) processing each of the one or more images to determine the location of the object in the each of the one or more images, to provide an respective image location for each of respective image; (f) for each of the one or more images, determining a respective expected image location of the object in that image, wherein the expected image location is determined using an initial predefined estimate of camera parameters and the physical location of the object 104 in the predefined coordinate system at the time instant corresponding to the time instant said respective image was captured; (g) optimizing estimates of camera parameters of the camera and/or optimizing an estimate of the position of the camera and/or optimizing an estimate of the orientation of the camera, by minimizing reprojection errors for each of said one or more images, wherein the reprojection error of a respective image is the difference between the expected image location of the object for that image and the image location of the object in said image. There is further provided methods for determining and methods for estimating, a physical location of a subject located within a predefined coordinate system, and methods for tracking the position of a subject, each of which use at least one camera which have been calibrated using the aforementioned method for calibrating a camera.