Camera-Based Orientation Correction for Magnetic Disturbances
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Solution Overview
Problem
Existing outdoor activity equipment with orientation devices, such as those using AHRS and GPS, face inaccuracies due to metal and magnetic disturbances, and more accurate inertial sensors are often too expensive, heavy, and large for practical use.
Innovation Solution
A system combining a camera, orientation detector, GPS receiver, and processor to identify reference objects in images, calculate orientation relative to a velocity vector, and correct inertial orientation data using image processing and GPS data, enabling accurate orientation estimation with lightweight and cost-effective components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetometers and AHRS sensors are used for orientation detection, then the system remains lightweight and cost-effective, but measurement precision deteriorates due to metal and magnetic disturbances
Solution Approach 1:
The patent introduces visual reference objects captured by the camera as an intermediary element. Instead of directly measuring orientation with magnetic sensors that are affected by disturbances, the system uses the camera to capture images of known reference objects, calculates their positions and orientations, and uses these visual measurements as a mediator to correct the magnetic sensor readings, thereby eliminating the direct harmful effect of magnetic disturbances on the final orientation measurement
Solution Approach 2:
The system continuously compares the orientation calculated from visual reference objects with the orientation measured by magnetic sensors, calculates the difference (error), and uses this feedback to correct the magnetic sensor readings. This closed-loop feedback mechanism compensates for magnetic disturbances by continuously adjusting the orientation measurement based on the more reliable visual reference data
2Measurement precision
If more accurate inertial sensor systems are used, then measurement precision improves, but device complexity, weight, and cost increase
Solution Approach 1:
Instead of using expensive and complex high-precision inertial sensors, the patent creates a visual copy of the orientation information by capturing images of reference objects with a standard camera. The system processes these image copies to extract orientation data, which then serves as a reference for correcting the magnetic sensor measurements, achieving high precision without the need for expensive inertial measurement units
Solution Approach 2:
The camera serves multiple functions: it captures images for visual reference object identification, provides orientation information through image processing, and acts as a correction reference for magnetic sensors. This multi-functionality allows the system to achieve high measurement precision using a standard camera rather than requiring specialized expensive sensors
Data Source
AI summary
A method and system including a camera adapted to capture frame image data, an orientation detector adapted to sense an orientation of the camera relative to an inertial frame of reference, a GPS receiver adapted to generate location data indicative of a velocity vector of the system relative to the inertial frame of reference, and a processor adapted to: upon receiving a frame image data, identify reference objects in the frame image data, calculate an orientation of the camera relative to the velocity vector based on a displacement of the reference object between at least two frames, predict an orientation of the camera relative to the velocity vector based on the sensed orientation by the detector, calculate a correction for the sensed orientation by comparing the calculated orientation to the predicted orientation, and upon receiving a sensed orientation, use the orientation correction for calculating a corrected orientation.