Laser Speckle Profile Classification for Assembly Validation
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Solution Overview
Problem
Conventional imaging systems are inadequate for accurately verifying the placement and orientation of components in assemblies, especially when materials have similar surface characteristics, leading to human error and inefficiency in inspection processes.
Innovation Solution
A method utilizing coherent light, such as a laser, to generate interference speckle patterns, which are then analyzed by an optical sensing system to distinguish between components and work surfaces, enabling accurate verification of placement and orientation, even for materials that are difficult to visually differentiate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual inspection is used to verify component placement, then inspection accuracy can be maintained through human interpretation, but inspection speed is slow and human error occurs
Solution Approach 1:
The patent replaces manual visual inspection with an automated optical sensing system that uses laser speckle patterns. The system scans a laser across the component surface and captures speckle responses, which are then processed by a controller to automatically determine proper placement and orientation. This substitution eliminates human interpretation errors while maintaining high measurement precision through objective optical measurements.
2Extent of automation
If conventional camera-based inspection systems are used, then automation of the inspection process is achieved, but the systems cannot resolve small features on large tools or distinguish materials with similar surface characteristics
Solution Approach 1:
The patent changes the illumination parameter from conventional broadband light to coherent laser light. This parameter change creates speckle patterns that are highly sensitive to surface microstructure and material properties. The speckle response varies based on the optical characteristics of different materials, enabling the system to distinguish between components and work surfaces even when they have similar macroscopic appearance. This allows automated inspection to achieve the measurement precision previously only attainable through manual inspection.
3Measurement precision
If laser speckle patterns are used to distinguish materials, then accurate differentiation of similar materials is achieved, but the inspection system complexity increases
Solution Approach 1:
The patent makes the laser scanning system multi-functional by using the same coherent light source and scanning mechanism for both guiding component placement and inspecting placement accuracy. The controller processes speckle responses to determine both location and orientation information. This universal approach avoids the need for separate inspection systems, thereby reducing overall system complexity while maintaining high material differentiation accuracy.
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 provides consistent and accurate inspection results by leveraging the unique interference patterns produced by coherent light, overcoming the limitations of camera-based systems and reducing reliance on manual inspection, thereby improving the precision and speed of assembly validation.
Implementation Method 1
An optical sensing system records the optical characteristics of an interference speckle produced by scattered coherent light from the coherent light source
Implementation Method 2
interference speckle produced by scattered coherent light from the coherent light source
Data Source
AI summary
A method for validating the placement of pieces in an assembly task by scanning a coherent light source, such as a laser, over a surface and characterizing the detected interference speckle pattern to discriminate the position of the placed piece from the surface on which the piece is placed. This discrimination is possible even if the characteristic features of the piece and background are smaller than the resolution of the scanning system. In addition, characteristics of the piece, such as the orientation of fibers in the material, may be sensed by classification of the associated speckle response.