Welded Steel Pipe Seam Detection Using Dual-Wavelength Imaging

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Solution Overview

Problem

Existing position detection methods for seam and heating portions in welded steel pipes are inaccurate due to surface irregularities, temperature fluctuations, and the influence of oxide films, leading to detection errors and increased operational costs.

Innovation Solution

A position detection apparatus using a light source that irradiates the seam and heating portions with specific wavelength ranges, combined with an imaging unit having multiple channels to capture and process reflection and radiation images, allowing for accurate alignment and detection of these portions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If visual observation by operator is used to detect seam portion position, then detection is possible, but detection precision deteriorates due to difficulty in visual recognition from red heat light and oxide film adhesion

Engineering Contradiction:
Improveseam portion position detection precisionVSAvoidoperator safety and operational efficiency
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the manual visual observation method with an automated optical detection system. A camera captures images of the seam portion, and image processing automatically determines its position. This substitution eliminates the need for operators to visually inspect the glowing seam portion, resolving the contradiction between detection precision and operational safety/efficiency.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If electromagnetic method is used to detect seam portion position, then direct detection is possible, but detection precision deteriorates due to surface shape irregularities and temperature distribution

Engineering Contradiction:
Improveseam portion position detection precisionVSAvoidsurface shape influence and temperature disturbance
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent utilizes the color characteristics of the seam portion (which appears different due to oxidation and surface properties) to detect its position. By capturing images and analyzing color differences in the seam portion compared to the base material, the system achieves precise detection without being affected by surface irregularities or temperature variations that plague electromagnetic methods.

Inventive Principle:
Principle #32Color changes

3Measurement precision

If marking method is used to detect seam portion position, then position tracking is possible, but device complexity increases due to additional marking and reading equipment

Engineering Contradiction:
Improveseam portion position detection precisionVSAvoidmarking device and reading device configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs the seam portion's own inherent characteristics (color difference caused by oxidation and surface properties) as the detection target. No external marking is needed; the seam portion itself serves as the marker through its natural visual differences from the base material. This self-service approach eliminates the need for separate marking and reading devices, reducing system complexity while maintaining detection precision.

Inventive Principle:
Principle #25Self-service

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

The method enables precise detection of seam and heating portions with a cost-effective and simple configuration, reducing detection errors and operational costs while maintaining high accuracy.

Implementation Method 1

an imaging unit having a plurality of different channels and configured to capture an image of each of the seam portion and the heating portion irradiated with the light by the light source... a second channel capable of receiving light in a second wavelength range corresponding to radiation light from the heating portion

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 2

a light source configured to irradiate the seam portion and the heating portion with light in a first wavelength range... a reflection image of the seam portion and a radiation image of the heating portion are in a state of being optically aligned

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP4257260B1Position detection device for SEAM portion and heated portion in welded steel pipe, manufacturing equippment of welded steel pipe, position detection method for SEAM portion and heated portion in welded steel pipe, manufacturing method of welded steel pipe, and quality control method for welded steel pipe
Publication Date: 2026.02.11 JFE STEEL CORP
  • EP4257260B1 patent drawingFigure 1~2
  • EP4257260B1 patent drawingFigure 3~4
  • EP4257260B1 patent drawingFigure 5~6

AI summary

A position detection apparatus for a seam portion and a heating portion of a welded steel pipe is a position detection apparatus configured to detect a position of the seam portion of the welded steel pipe and a position of the heating portion, the position detection apparatus including a light source configured to irradiate the seam portion and the heating portion with light in a first wavelength range, an imaging unit configured to capture an image of each of the seam portion and the heating portion irradiated with the light by the light source, and an image processing unit configured to process the image captured by the imaging unit and to detect the position of each of the seam portion and the heating portion, in which the imaging unit includes a first channel capable of receiving the light in the first wavelength range, and a second channel capable of receiving light in a second wavelength range corresponding to radiation light from the heating portion.