Crash Dummy Motion Measurement Using Camera-Based Coordinate Conversion
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Solution Overview
Problem
Current technologies lack the capability to accurately measure the motion response trajectory of a crash dummy during vehicle crash tests, as existing methods require sensor installation which is not feasible for all parts of the dummy.
Innovation Solution
A method involving image acquisition of a measurement mark on the dummy using a camera, with subsequent conversion of coordinate positions to determine the motion response, utilizing a preset coordinate system aligned with the motion direction of the platform, and adjusting pixel cell orientation to minimize conversion complexity and errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a camera is used to capture images of the measurement mark, then the measurement can be performed without sensor installation on the dummy, but the measurement precision may be insufficient due to coordinate system conversion errors
Solution Approach 1:
The patent applies preliminary action by pre-defining the coordinate system configuration before measurement. Specifically, the pixel cell orientation is pre-adjusted to be parallel or perpendicular to the coordinate axes, and the conversion relationship between image coordinates and physical coordinates is pre-established. This preliminary setup ensures that when actual measurement occurs, the coordinate conversion introduces minimal error, thus maintaining high measurement precision while using the convenient camera-based approach without sensor installation.
2Ease of operation
If the pixel cells are not aligned with the coordinate axes, then the measurement can be performed with general camera positioning, but the conversion complexity and calculation errors increase
Solution Approach 1:
The patent applies parameter changes by modifying the orientation parameter of the pixel cells. Instead of allowing arbitrary camera positioning with complex angular relationships, the method constrains the pixel cell orientation to be parallel or perpendicular to the coordinate axes. This parameter change simplifies the coordinate conversion from a general affine transformation to a simpler scaling and translation operation, reducing calculation complexity and errors while maintaining ease of operation through standardized positioning.
Data Source
AI summary
A method for measuring the motion response of a dummy in a crash test comprises: acquiring images of a measurement mark by a camera during the crash test, wherein the measurement mark is fixed on a part to be measured of the dummy, and the dummy is set in association with a preset platform; determining first coordinate positions of the measurement mark in the images; determining corresponding second coordinate positions of the first coordinate positions in a static coordinate system according to a preset conversion relationship, wherein the X-axis of the static coordinate system is parallel to the motion direction of the preset platform, the Y-axis of the static coordinate system is perpendicular to the motion direction of the preset platform; and determining a motion response trajectory of the part to be measured according to an initial position of the part to be measured and the second coordinate positions.