Optical Weld Seam Inspection via Intensity Triangulation
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Solution Overview
Problem
Current methods for determining three-dimensional test contours, such as weld seams, require separate hardware and steps for 2D and 3D inspections, leading to increased hardware complexity and examination time, especially when the weld seam is at the same height as the surrounding sheet metal, making it difficult to accurately locate and detect minor irregularities.
Innovation Solution
Generating a two-dimensional intensity image from light line images on an optical sensor, allowing for precise definition of the test area, and then performing three-dimensional inspection only within that area using light section triangulation, reducing the need for extensive scanning and hardware by differentiating between the weld seam and surrounding areas based on brightness and edge detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate 2D and 3D inspection methods are used with different hardware, then the precision of weld seam location and defect detection is improved, but the hardware complexity and examination time increase
Solution Approach 1:
The patent combines 2D intensity image analysis and 3D light section triangulation into a single integrated inspection system. The same optical sensor captures both intensity information (for locating weld seams) and height information (for detecting defects), eliminating the need for separate hardware systems while maintaining detection precision.
Solution Approach 2:
The optical sensor serves multiple functions: it captures intensity images to locate weld seams and simultaneously captures light line images for 3D height measurement. This multi-functionality reduces hardware complexity while maintaining the ability to perform both localization and defect detection with high precision.
2Measurement precision
If separate 2D and 3D inspection methods are used with different hardware, then the precision of weld seam location and defect detection is improved, but the examination time increases
Solution Approach 1:
The system performs both 2D intensity analysis and 3D light section triangulation continuously during a single scan pass. The optical sensor continuously captures images that are processed to extract both intensity information for weld seam localization and height information for defect detection, eliminating the need for separate inspection passes and reducing total examination time.
Solution Approach 2:
The system first performs 2D intensity image analysis to locate weld seams, then uses this preliminary information to guide the 3D inspection only in the identified weld areas. This preliminary localization action enables subsequent focused 3D defect detection, reducing the overall inspection time compared to scanning the entire area with 3D methods.
3Ease of manufacture
If the entire extent of the weld seam is scanned using the 3D method, then the need for preliminary 2D defect selection is eliminated, but the examination time and data processing effort increase excessively
Solution Approach 1:
The system performs preliminary 2D intensity image analysis to locate weld seams and identify areas of interest before conducting 3D light section triangulation. This preliminary action enables the system to focus 3D inspection only on relevant weld areas, eliminating the need to scan the entire extent and reducing data processing effort while maintaining inspection simplicity.
Solution Approach 2:
The system applies different inspection methods to different areas: 2D intensity analysis is applied to the entire field of view to locate weld seams, while 3D light section triangulation is applied only to the identified weld areas. This localized application of inspection methods reduces examination time and data processing effort while maintaining comprehensive defect detection capability.
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 reduces hardware complexity and examination time by enabling precise identification of the test area and efficient three-dimensional inspection, effectively locating weld seams and detecting impermissible elevations or depressions without unnecessary extensive scanning.
Implementation Method 1
A fan-shaped light beam, i.e. spread out in only one plane, is radiated onto the surface to be examined, produces a light line there and is observed at an angle
Implementation Method 2
the check for defects in the weld seam is then carried out using a 3D method, i.e. determining the height of the profile of the weld seam and the like. in particular by means of the special light section triangulation method
Data Source
Figure 1a
Figure 1b
Figure 2a~2b
AI summary
A probe is moved in the direction of a test contour of object, to extract individual recordings of to-be-tested longitudinal positions of object. The light intensity at each position of object image (4) in extension direction (8), is determined from the images of line of light. Intensity gradients are produced from a two-dimensional image of light lines. The lateral edges of test contour are determined from two-dimensional image intensity. The dimensional examination of test contour is performed in a region of actual width, by light section triangulation.