Composite Workpiece Inspection Using Oblique Laser Line
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Solution Overview
Problem
Conventional systems for inspecting composite structures using machine vision technologies are limited in accuracy and reliability due to variations in composite material reflectivity, fiber orientation, and surface irregularities, leading to inefficiencies and operator errors in detecting features like ply boundaries, tape edge gaps, and foreign object debris during the composite tape lay-up process.
Innovation Solution
The system employs a method of illuminating the workpiece with an oblique incidence angle and capturing images to generate both two-dimensional and three-dimensional information, allowing for the isolation and classification of features such as foreign object debris, using algorithms that analyze power histograms, intensity thresholds, and step filter kernels to provide accurate feature detection and classification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual visual inspection is employed to verify ply boundaries and detect inconsistencies, then measurement accuracy can be achieved, but production efficiency decreases and operator error increases
Solution Approach 1:
The patent replaces manual visual inspection with an automated optical inspection system that uses a laser projector to generate structured light patterns and a camera to capture images. The system automatically processes images to detect ply boundaries, gaps, overlaps, and foreign object debris, eliminating operator error and maintaining high measurement accuracy while significantly improving production efficiency by enabling continuous inspection without stopping the tape laying process
Solution Approach 2:
The patent introduces an intermediary processing step between laser illumination and image capture that involves generating synthetic depth information through image processing algorithms. The system creates a depth map from the laser line distortion, which serves as an intermediary representation that enhances the detection of surface features and defects, thereby maintaining measurement accuracy while enabling automated operation
2Productivity
If machine vision systems use standard imaging to detect surface features, then inspection speed can be maintained, but measurement precision deteriorates due to material reflectivity variations and surface irregularities
Solution Approach 1:
The patent transitions from two-dimensional image analysis to three-dimensional surface characterization by using structured light projection. The laser line distortion caused by surface topography is captured and processed to generate depth information, adding a third dimension (depth/height) to the inspection data. This enables accurate measurement of ply boundaries, gaps, and overlaps regardless of material reflectivity variations or fiber orientation, while maintaining high inspection speed through automated processing
Solution Approach 2:
The patent changes the illumination parameter from conventional omnidirectional lighting to directional laser line projection at a specific angle. This parameter change creates sensitivity to surface topography, where the laser line distorts according to the surface profile. By processing these distortions, the system achieves precise measurement of surface features independent of material optical properties, thereby improving measurement accuracy without sacrificing inspection speed
3Loss of information
If laser projection is used to illuminate the workpiece, then three-dimensional information can be obtained, but detection reliability decreases due to motion blur and out-of-focus conditions
Solution Approach 1:
The patent acknowledges the dynamic nature of the inspection process where the workpiece moves at high velocity during tape laying. Rather than attempting to freeze motion, the system dynamically adapts by using short exposure times and processing algorithms that account for motion blur. The system captures the distorted laser line pattern caused by both topography and motion, then uses image processing to separate and analyze the topographic information, maintaining detection reliability while preserving three-dimensional measurement capability
Solution Approach 2:
The patent implements a feedback mechanism where the captured image quality and laser line distortion are continuously analyzed. The system uses the captured data to refine its measurement algorithms and compensate for motion effects. By feeding back the processed information to adjust detection parameters and algorithms, the system maintains reliable detection of surface features even under dynamic conditions with motion blur and varying focus
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 enhances the reliability and accuracy of workpiece inspection, improves production quality and efficiency, and reduces manufacturing costs by enabling real-time feature detection and classification during the composite tape lay-up process.
Implementation Method 1
a laser projector is employed that generates a laser signature on the workpiece, while a camera is used to capture an image of the workpiece that includes the laser signature illuminated thereon
Data Source
AI summary
Apparatus and methods for inspecting a workpiece are provided. According to one embodiment, a method for inspecting a workpiece comprises illuminating at least a portion of the workpiece with at least one illumination beam and capturing at least one image including at least on line signature formed by illuminating the workpiece with the illumination beam. The method further includes performing two-dimensional and three-dimensional processes on the captured image and classifying at least one feature associated with the workpiece based at least in part on data generated by the two-dimensional and three-dimensional processes.