CCD-Based Joint Part Detection in Endless Hot Rolling

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Solution Overview

Problem

Existing methods for detecting joint parts in an endless hot rolling process are prone to errors due to temperature variations and noise interference, making it difficult to accurately identify the edge line of the steel strip, which affects the cutting precision and yield of the final product.

Innovation Solution

A device and method utilizing a CCD camera, optical filter, and tracking unit to detect the edge line of the steel strip by analyzing the sum of gray levels and comparing the mean profile values, which helps to distinguish the joint part from other regions and reduce noise interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional methods calculate joint part position using sheet pressure and strand roll speed from finishing mill output, then joint part detection is achieved, but measurement precision deteriorates due to error accumulation from multiple calculation steps

Engineering Contradiction:
Improvejoint part position detection accuracyVSAvoiddetection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the conventional mechanical calculation method (using sheet pressure and roll speed measurements from finishing mill stands) with an optical detection system. A CCD camera captures images of the steel strip, and image processing algorithms directly determine joint part positions, eliminating the need for complex mechanical parameter calculations and reducing error accumulation.

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

Solution Approach 2:

The patent introduces an optical intermediary (CCD camera and image processing system) between the steel strip and the detection system. Instead of directly measuring mechanical parameters at multiple stands, the system uses optical imaging as an intermediary to capture strip characteristics, which are then processed to identify joint parts, simplifying the overall detection process.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If temperature-based detection methods are used to identify joint parts, then detection capability is provided, but measurement precision deteriorates due to temperature variations and noise interference

Engineering Contradiction:
Improveedge line detection accuracyVSAvoidtemperature variation and noise interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the detection parameter from temperature-based measurements to optical image-based measurements. By capturing images of the steel strip and analyzing edge lines through image processing, the system avoids the harmful effects of temperature variations and noise that plague conventional temperature-based detection methods.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes optical image characteristics (effectively using light reflection and absorption properties) to detect joint parts. The CCD camera captures visual information from the steel strip, and image processing algorithms analyze variations in the captured images to identify joint part positions, replacing temperature-based detection with optical property-based detection.

Inventive Principle:
Principle #32Color changes

3Productivity

If joint part detection accuracy is improved to reduce cutting errors, then productivity is enhanced, but device complexity increases due to additional detection equipment

Engineering Contradiction:
Improvecutting precision and yieldVSAvoiddetection system configuration
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent makes the detection system universal by using a CCD camera and image processing algorithm that can detect joint parts at any position along the steel strip without requiring multiple specialized sensors. The same optical system serves multiple detection functions, reducing overall device complexity while maintaining high detection accuracy.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent creates an optical copy (image) of the steel strip using a CCD camera, and then analyzes this copy to detect joint parts. This approach allows accurate detection without physically interfering with the steel strip or requiring complex mechanical measurement devices, thereby improving productivity while keeping the detection system relatively simple.

Inventive Principle:
Principle #26Copying

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

Enables precise detection of joint parts between preceding and following coil materials, improving cutting accuracy and reducing errors, thereby enhancing the productivity and quality of the steel sheet production.

Implementation Method 1

an optical filter (85) which transmits a wavelength of the light source

Methodology Applied
Scientific EffectOptical filtering: Filter (optical)

Implementation Method 2

a CCD camera (80) which receives an image of the steel strip

Methodology Applied
Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentEP2222423B1Device and method for detecting the jointed parts of strip in the endless hot rolling process
Publication Date: 2015.08.05 POHANG IRON & STEEL CO LTD
  • EP2222423B1 patent drawingFigure 1~3
  • EP2222423B1 patent drawingFigure 4
  • EP2222423B1 patent drawingFigure 5

AI summary

There are provided a device and method for detecting joint parts of a steel strip in an endless hot rolling process. In particular, there are provided a device and method for accurately detecting joint parts of a steel strip in an endless hot rolling process. The device for detecting joint parts of a steel strip in an endless hot rolling process includes an image signal collection block receiving image signals, each having information on gray level pixels of a steel strip, from a charge coupled device (CCD) camera; an edge line detection block receiving the image signals from the image signal collection block to detect an edge line of the steel strip; a profile calculation block receiving information on the detection of the edge line from the edge line detection block to calculate the sum of gray levels up to an edge line of the steel strip in a traverse direction of the steel strip when the edge line is detected by the edge line detection block; a joint part judgement block receiving information on the sum of the gray levels, which shows a current profile value, from the profile calculation block to judge the edge line as a joint part when a ratio of a mean value of the current profile and a mean value of the previous profile is less than a predetermined value; and an output block receiving information on the judgement of the edge line as the joint part from the joint part judgement block to output a joint part-detecting signal when the edge line is judged to be a joint part.