Coating Surface Defect Imaging for Reproducible Quality Assessment

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Solution Overview

Problem

Current methods for assessing coating surface defects in paints and varnishes are subjective, time-consuming, and lack reproducibility, making it difficult to predict coating quality and identify optimal defoamer compositions, as manual evaluation is coarse-grained and influenced by various interdependent process parameters.

Innovation Solution

A method using a defect-identification program that processes digital images to recognize and characterize coating surface defects objectively and reproducibly, combining machine learning models to predict defoamer ratios and optimize coating surface quality by automatically detecting defects like bubbles and cratering, and adjusting defoamer compositions based on quantitative analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual visual assessment by employees is used to evaluate coating surface defects, then human experience and judgment can be utilized, but the assessment becomes subjective, time-consuming, and lacks reproducibility

Engineering Contradiction:
Improvedefect assessment accuracyVSAvoidevaluation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the manual visual assessment mechanism with an automated image processing system that captures coating surfaces and uses algorithmic analysis to identify and classify defects. This substitution eliminates human subjectivity and time constraints while maintaining or improving assessment accuracy through consistent, reproducible measurement criteria.

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

Solution Approach 2:

The system enables the coating surface itself to provide assessment information through its optical properties. By capturing images of the coating under controlled lighting conditions and analyzing the reflected or transmitted light patterns, the system allows the coating to 'self-report' its defect characteristics without requiring external human interpretation.

Inventive Principle:
Principle #25Self-service

2Adaptability or versatility

If manual evaluation methods are used, then flexibility in handling various substrate types and pretreatments is maintained, but the process becomes highly dependent on employee experience and yields inconsistent results

Engineering Contradiction:
Improvehandling of various substratesVSAvoidreproducibility of defect identification
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The image processing system is designed with universal applicability across different substrate types (wood, plastic, metal, glass) and pretreatment conditions. The same core algorithmic framework and defect recognition models can be applied uniformly to all substrate categories, ensuring consistent and reproducible results regardless of the specific material being evaluated.

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

3Productivity

If automated inspection systems are implemented, then objectivity and speed of defect detection are improved, but the complexity of the system increases

Engineering Contradiction:
Improvedefect detection speedVSAvoidinspection system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system creates digital copies (images) of the coating surfaces that can be analyzed without physically handling or manipulating the actual substrates. This copying approach simplifies the physical inspection process while enabling rapid, automated analysis of multiple samples simultaneously, improving productivity without proportionally increasing system complexity.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP3971557B1Qualitative or quantitative characterization of a coating surface
Publication Date: 2025.01.15 EVONIK OPERATIONS GMBH
  • EP3971557B1 patent drawingFigure 1~3
  • EP3971557B1 patent drawingFigure 4~5B
  • EP3971557B1 patent drawingFigure 5C~5D

AI summary

The invention relates to a method for qualitative and/or quantitative characterization of a coating surface, the method comprising: - providing a defects-identification program (124) configured to recognize coating surface defect types (1204, 1206, 1306, 1308); - determining, by the defects-identification program, whether at least one camera (134) operatively coupled to the defects-identification program is positioned within a predefined distance range and/or within a predefined image acquisition angle range relative to a currently presented coating surface; in dependence on the result of the determination: ∘ generating a feedback signal whether adjustment of the position of the at least one camera is required such that the camera is within the predefined distance range and/or within the predefined image acquisition angle range; and/or ∘ automatically adjusting the relative distance of the at least one camera and and/or automatically adjusting the angle of the at least one camera; - enabling the camera to acquire a digital image (604, 606, 1202) of the presented coating surface only in case the camera is within the predefined distance range and/or image acquisition angle range; - processing (102) the digital image (604, 606, 1202) for recognizing coating surface defects; and - outputting (104) a characterization of the coating surface.