Monocular Vision Calibration for Linear and Angular Accelerometers
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Solution Overview
Problem
Existing methods for calibrating linear and angular accelerometers are hindered by high costs, complex operations, limited frequency range, and low precision, with current monocular vision methods only suitable for linear vibration calibration.
Innovation Solution
A method utilizing monocular vision for calibrating both linear and angular vibrations by installing a feature mark and accelerometer on a vibration generating device, acquiring motion sequence images and output signals, determining correspondence matrices, fitting acceleration peaks using sine approximation, and calculating sensitivity according to ISO 16063-1.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If comparison method is used for calibration, then operation simplicity and cost are improved, but calibration precision deteriorates (only about 1%)
Solution Approach 1:
The patent replaces the mechanical comparison method with a vision-based measurement system. An industrial camera captures motion sequences of a feature mark, and image processing algorithms calculate displacement and acceleration, eliminating the need for physical reference accelerometers and their associated alignment and calibration complexities.
Solution Approach 2:
The patent introduces a feature mark as an intermediary object between the vibration source and the measurement system. This feature mark serves as a visual reference that mediates the measurement process, allowing the vision system to accurately track motion and derive acceleration data without direct contact with the accelerometer under test.
2Adaptability or versatility
If laser interferometry is used for calibration, then calibrating range is improved (0.1 Hz to 20 kHz), but device complexity and cost increase significantly
Solution Approach 1:
The patent replaces the complex laser interferometry system with a simpler vision-based system. Instead of using lasers, interferometers, and precise optical paths, the patent uses an industrial camera to capture images and process them through algorithms to achieve acceleration measurement across a wide frequency range.
Solution Approach 2:
The patent creates a visual copy of the physical motion through image capture. By capturing the motion sequence of the feature mark and processing the image data, the system recreates the acceleration information in digital form, eliminating the need for complex optical measurement systems.
3Adaptability or versatility
If laser interferometry is used for calibration, then calibrating range is improved, but operation complexity increases
Solution Approach 1:
The patent implements self-service through automated image processing. The system automatically captures images, processes them through edge detection and coordinate transformation algorithms, and calculates acceleration data without requiring manual intervention or complex operational procedures.
Solution Approach 2:
The patent replaces manual operational procedures with automated vision-based measurement. The system performs calibration operations automatically through image capture and processing, eliminating the need for manual setup, alignment, and measurement procedures associated with laser interferometry.
4Ease of operation
If existing monocular vision method is used, then operation simplicity and cost are improved, but application scope deteriorates (only suitable for linear vibration)
Solution Approach 1:
The patent enhances the universality of the monocular vision method by developing algorithms that can handle both linear and angular vibration calibration. The system uses a feature mark with specific geometric characteristics that allow the vision system to extract both translational and rotational motion information from the same image sequence.
Solution Approach 2:
The patent extends the measurement capability from one dimension (linear) to multiple dimensions (linear and angular) by utilizing the spatial information contained in the image sequence. Through coordinate transformations and geometric analysis of the feature mark's motion, the system derives both linear acceleration and angular acceleration data.
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
The method provides a stable, flexible, and cost-effective calibration of linear and angular accelerometers across various frequencies and models, achieving high-precision sensitivity measurement and unifying vibration measurement systems.
Implementation Method 1
acquiring, by an industrial camera, a motion sequence image of the feature mark
Implementation Method 2
a linear-angular vibration generating device; reproducing an exciting acceleration of a linear and angular accelerometer based on monocular vision
Data Source
AI summary
A method for calibrating linear vibration and angular vibration based on monocular vision. A motion sequence image of a feature mark is acquired by an industrial camera, and an output signal of a linear and angular accelerometer is acquired by a data acquisition card, where the feature mark and the linear and angular accelerometer are fixed on a work table. An exciting acceleration of the linear and angular accelerometer is measured by a monocular vision method integrating a camera calibration method and a sub-pixel edge extraction method based on line segment detection. The exciting acceleration and the output signal are fitted by a sine approximation method, respectively, and corresponding fitted peaks are obtained. A sensitivity of the linear and angular accelerometer is obtained according to the fitted peaks.