Six-Degree-of-Freedom Measurement via Physical Decoupling
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Solution Overview
Problem
Traditional machine vision-based six-degree-of-freedom measurement methods face challenges in achieving high-precision and real-time measurements due to low computing accuracy and high calculation complexity, particularly in nonlinear mathematical models.
Innovation Solution
The method employs a point projector, rear-projection screen, and camera to map spatial six-degree-of-freedom motion into plane motion, using physical decoupling and coordinate transformation to simplify the mathematical model, reduce calculation, and improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a nonlinear mathematical model is used for six-degree-of-freedom decoupling in traditional machine vision measurement, then the measurement capability is achieved, but the computing accuracy is low and the calculation amount is large
Solution Approach 1:
The patent transforms the six-degree-of-freedom spatial motion measurement problem into a two-dimensional plane motion measurement problem by projecting laser beams onto a rear-projection screen. The point projector emits three laser beams along orthogonal axes, and their projections on the screen create elliptic laser points whose plane coordinates are used to calculate the six-degree-of-freedom information through a simplified decoupling model, reducing computational complexity while maintaining measurement accuracy
Solution Approach 2:
The patent segments the complex six-degree-of-freedom measurement into three separate laser beam measurements. Each laser beam corresponds to one spatial axis, and by measuring the plane coordinates of the three elliptic laser points independently and then combining them through coordinate transformation, the overall measurement complexity is reduced while achieving accurate six-degree-of-freedom decoupling
2Measurement precision
If a nonlinear mathematical model is used for six-degree-of-freedom decoupling, then measurement capability is provided, but the calculation amount is large preventing real-time measurement
Solution Approach 1:
The patent achieves real-time measurement capability by dimensionality reduction - transforming 3D spatial motion into 2D plane motion on the rear-projection screen. The simplified decoupling model based on plane coordinates requires significantly less computation than traditional nonlinear models, enabling real-time calculation of six-degree-of-freedom information while maintaining high measurement accuracy
Solution Approach 2:
The patent changes the measurement parameters from direct three-dimensional spatial coordinates to two-dimensional plane coordinates on the projection screen. This parameter transformation simplifies the mathematical relationships in the decoupling model, reducing calculation amount and enabling real-time measurement while preserving the ability to accurately determine six-degree-of-freedom motion parameters
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 enables simultaneous, high-precision, and real-time six-degree-of-freedom measurement with reduced computational load, enhancing measurement reliability and cost-effectiveness by transforming spatial motion into plane motion.
Implementation Method 1
a point projector and a rear-projection screen are employed to equivalently map a spatial six-degree-of-freedom motion to a plane motion of three laser points
Implementation Method 2
performing an image processing on the image sequence; utilizing an edge detection and a least squares method to obtain plane coordinates of center points of three ellipses as coordinates of three elliptic laser points
Data Source
AI summary
A six-degree-of-freedom measurement method by machine vision based on physical decoupling. A point projector capable of emitting three laser beams perpendicular to each other is placed on a measured object. A rear-projection screen is configured to allow the three laser beams to be projected thereon as three laser points. The collection of motion images is performed by a camera. Plane coordinates of the three laser points are obtained by processing a sequence image. A mathematical decoupling model is built according to a nature of sphere and a spatial position relationship of three laser beams. The plane coordinates of the three laser points are input into the mathematical decoupling model to obtain six-degree-of-freedom information of the measured object.