3D Assembly Verification Using Multi-Camera Triangulation
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Solution Overview
Problem
Current methods for assembly verification in machine vision are inefficient, often requiring manual repositioning of single-point sensors and being time-consuming, especially when dealing with multiple 3D position measurements in complex assemblies.
Innovation Solution
The use of multiple cameras to perform triangulation for 3D position measurement of subcomponents, allowing for simultaneous measurement of multiple points and accommodating arbitrary part poses, with pre-calibrated camera systems for rapid reconfiguration and accurate verification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If single-point sensors are used for 3D measurement, then measurement precision is improved, but productivity deteriorates due to sequential measurement requirements
Solution Approach 1:
The patent divides the measurement task into multiple independent measurement points, each captured by separate cameras simultaneously. Instead of using one sensor to measure all points sequentially, the system segments the measurement into parallel operations where each camera captures a specific point in the same time frame, eliminating sequential bottlenecks while maintaining precision through dedicated measurement zones.
Solution Approach 2:
The patent transitions from sequential temporal measurement to parallel spatial measurement by introducing multiple cameras positioned at different locations. This dimensional expansion allows simultaneous capture of multiple 3D points across the assembly, converting a time-consuming sequential process into a parallel spatial operation that maintains precision while dramatically improving throughput.
2Measurement precision
If single-point sensors are manually repositioned for different parts, then measurement precision is maintained, but ease of operation deteriorates
Solution Approach 1:
The patent creates a universal measurement system where multiple cameras simultaneously serve as single-point sensors for different measurement locations. Each camera is dedicated to a specific measurement point, but the entire system collectively measures all points in parallel, eliminating the need to reposition sensors while maintaining the precision benefits of focused single-point measurement capability.
Solution Approach 2:
The patent uses multiple camera copies positioned at different locations, each capturing measurements from its specific viewpoint. Instead of moving one sensor to multiple positions, the system creates spatial copies of the measurement capability, allowing simultaneous measurement at all positions without repositioning burden while maintaining the precision of individual point measurement.
3Measurement precision
If laser-based sensors scan parts to measure multiple 3D positions, then measurement precision is improved, but productivity deteriorates due to scanning time
Solution Approach 1:
The patent segments the scanning function into multiple independent camera units, each capturing a portion of the assembly simultaneously. Instead of one laser scanning the entire part sequentially, the system divides the measurement task across multiple cameras that capture their respective zones in parallel, maintaining precision through dedicated capture while eliminating sequential scanning delays.
Solution Approach 2:
The patent replaces continuous scanning with simultaneous periodic capture, where multiple cameras capture measurements at the same time instant rather than sequentially scanning through positions. This transforms the continuous scanning process into discrete simultaneous capture events, maintaining measurement precision while dramatically reducing the time required to obtain all 3D position data.
4Measurement precision
If structured illumination systems are used for 3D measurement, then measurement precision is improved, but productivity deteriorates due to long scanning time
Solution Approach 1:
The patent segments the structured illumination measurement into multiple independent camera-based measurement zones operating simultaneously. Instead of one structured illumination system scanning the entire assembly, multiple cameras each capture their designated zones in parallel, maintaining the precision benefits of structured measurement while eliminating the sequential scanning bottleneck that limits throughput.
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 faster and more accurate assembly verification, reducing waste and rework by allowing for fixtureless verification and rapid adaptation to changing parts, while simplifying the setup and operation process.
Implementation Method 1
measurement of the x,y,z (3D) position of each subcomponent is performed using triangulation from at least two, but often three cameras which acquire, respectively, two, or three images simultaneously
Data Source
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AI summary
A method and apparatus for assembly verification is disclosed. A measurement of the 3D position of each subcomponent is performed using triangulation from three cameras acquiring images simultaneously. An operator trains one 2D model, correspond to the same subcomponent of the assembly, per camera. At run-time, models are registered in each camera view so as to provide measured 3D position of the subcomponents. Then, measured 3D positions are compared with expected nominal 3D positions, and differences in 3D position are checked against tolerances. The invention simplifies the task of assembly verification, requiring only multiple cameras fixed above an assembly line. After minor operator activity, the invention can then perform assembly verification automatically. Since the invention can perform fixtureless assembly verification, a part can be presented to the machine vision system with arbitrary 3D position and orientation. Stroboscopic illumination can be used to illuminate parts on a rapidly moving assembly line.