Surface Inspection Using Color-Coded LED Illumination
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Solution Overview
Problem
Existing methods for detecting and recognizing surface features of continuously cast and rolled metallurgical products are inefficient in distinguishing between shadows and light sources, especially under production conditions, leading to incomplete data capture and processing challenges.
Innovation Solution
A method utilizing three light sources positioned at 120° angles with respect to the product surface, combined with a digital camera, captures detailed images of surface conditions, including defects, using LEDs of different colors, and optionally stereo technology for enhanced three-dimensional topology and contrast, allowing for rapid data storage and identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If multiple light sources are used to illuminate the product surface from different directions, then the information about surface characteristics can be enhanced, but it becomes impossible to distinguish whether the illuminated areas or shadows originate from one light source or another
Solution Approach 1:
Each light source is assigned a distinct color (red, green, blue) so that the illuminated areas and shadows can be clearly distinguished by their color characteristics. The digital camera captures these color-coded illumination patterns, allowing the evaluation device to determine surface characteristics without confusion about shadow origins.
Solution Approach 2:
The illumination from multiple light sources is segmented by color, with each light source emitting a specific wavelength range. This segmentation allows the evaluation device to process information from each light source independently, maintaining measurement precision while utilizing multiple illumination directions.
2Productivity
If three light sources arranged at 120° angles are used with a digital camera, then detailed surface information including defects can be captured rapidly, but the device complexity increases
Solution Approach 1:
The three light sources are activated sequentially in a periodic manner rather than simultaneously, allowing the digital camera to capture distinct images from each illumination angle. This periodic activation simplifies the evaluation process while maintaining the benefits of multi-directional illumination for rapid surface inspection.
Solution Approach 2:
The light sources are arranged in three-dimensional space at 120° angles around the product surface, utilizing spatial dimensionality to achieve comprehensive surface coverage. This 3D arrangement allows rapid capture of surface characteristics from multiple perspectives without requiring complex mechanical movement.
3Measurement precision
If LEDs of different colors are used to illuminate the product surface, then surface defects can be better identified, but the manufacturing complexity of the lighting system increases
Solution Approach 1:
The lighting system uses LEDs with different color parameters (wavelengths) to illuminate the product surface. By changing the color parameter of the light sources rather than using complex optical filters or mechanical systems, the patent achieves improved defect detection accuracy while keeping the manufacturing process relatively simple, as colored LEDs are commercially available off-the-shelf components.
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 the rapid and accurate determination and storage of extensive information about metallurgical product surfaces, facilitating clear identification for further processing, with improved contrast and error detection capabilities.
Implementation Method 1
A method utilizing three light sources positioned at 120° angles with respect to the product surface, combined with a digital camera, captures detailed images of surface conditions, including defects, using LEDs of different colors
Implementation Method 2
a digital camera 25 is provided with which the illuminated product surface 12 is recorded in a selected section with corresponding shadows and reflections
Data Source
Figure 1~2
Figure 3~4
Figure 5a~5c
AI summary
The method involves irradiating a defined section of the product surface (12) by two radiation sources (21,22,23) of different wavelengths, from different directions, and the irradiated surface section is optoelectronically detected. Three radiation sources are used as visible light sources. An image sensor (25), particularly a digital camera is used for the opto-electronic recording. An independent claim is also included for a device for executing the method.