Non-Flat Reference Surface Matching for Optical Inspection Accuracy

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Solution Overview

Problem

The curvature of non-flat target objects, such as car bodies and aircraft fuselages, affects the divergence of radiation beams used in optical spectroscopy, leading to inaccurate quality control measurements due to incomplete radiation detection, which results in significant error bars or undeterminable parameters in material properties and paint layer thicknesses.

Innovation Solution

A method involving irradiation of non-flat reference profiles to determine reference response data, followed by irradiation of the target object with a similar profile, allowing for the selection of the most comparable reference profile to determine the target object's parameters based on both reference and inspection response data, thereby improving accuracy and simplifying the inspection process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If optical spectroscopy is used to inspect non-flat target objects, then non-contact and non-destructive inspection of material properties is achieved, but the curvature affects radiation beam divergence causing incomplete detection and significant measurement errors

Engineering Contradiction:
Improvequality control parameters accuracyVSAvoidcurvature effect on radiation beam
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the reference parameter from a flat reference surface to a curved reference surface that matches the target object's curvature. By adapting the reference surface geometry parameter to match the target's curvature, the system compensates for beam divergence effects and eliminates measurement errors caused by the harmful curvature factor.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If a flat reference surface is used for reference measurements, then the inspection process is simple, but the curvature of the target object causes the radiation beam to diverge and not be entirely detected

Engineering Contradiction:
Improveinspection process simplicityVSAvoidradiation detection completeness
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies local quality by matching the reference surface curvature to the specific local curvature of the target object being inspected. Instead of using a universal flat reference, the system adapts the reference surface's geometric properties to locally match the target's curvature at the measurement location, ensuring complete radiation detection while maintaining process simplicity.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If the reference surface curvature is adapted to match the target object curvature, then measurement accuracy is improved, but the complexity of selecting and matching reference profiles increases

Engineering Contradiction:
Improveparameter determination accuracyVSAvoidreference profile matching complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-characterizing multiple reference surfaces with different curvature radii before inspection. The system stores reference data for each curvature variant, allowing rapid selection and matching during inspection without complex real-time calculations, thus improving measurement precision while managing complexity through advance preparation.

Inventive Principle:
Principle #10Preliminary action

4Adaptability or versatility

If multiple reference surfaces with different curvature radii are used, then the adaptability to different target profiles is improved, but the device complexity and number of reference objects increase

Engineering Contradiction:
Improvereference to target profile matchingVSAvoidnumber of reference surfaces
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent applies universality by designing a modular reference surface system where each reference surface can serve multiple inspection scenarios. The reference surfaces with different curvature radii are part of an integrated system that can be selected based on target characteristics, allowing a finite set of reference surfaces to handle a wide range of target curvatures efficiently, thus achieving high adaptability without requiring an excessive number of reference objects.

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

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 enhances the accuracy of determining material properties and paint layer thicknesses on non-flat surfaces by compensating for curvature effects, providing more precise and faster quality control with simpler methods, reducing errors and improving inspection efficiency.

Implementation Method 1

emitter system (40) to emit radiation (58)

Methodology Applied
Scientific EffectElectromagnetic radiation emission: Electromagnetic Induction

Implementation Method 2

detector system (42) to detect radiation (58)

Methodology Applied
Scientific EffectElectromagnetic radiation detection: Photoelectric Effect

Data Source

PatentEP3841374B1Method for inspection of a target object, control system and inspection system
Publication Date: 2023.08.02 ABB (SCHWEIZ) AG
  • EP3841374B1 patent drawingFigure 1~2
  • EP3841374B1 patent drawingFigure 3a~4
  • EP3841374B1 patent drawingFigure 5

AI summary

A method for inspection of a target object (38), the method comprising irradiating a reference surface (66) having a non-flat reference profile (68) with radiation (58); determining reference response data based on detected radiation (58) having interacted with the reference surface (66); irradiating a target object (38) with radiation (58), the target object (38) comprising a target surface (70) having a non-flat target profile (72) corresponding to the reference profile (68); determining inspection response data based on detected radiation (58) having interacted with the target object (38); and determining at least one parameter of the target object (38) based on the reference response data and the inspection response data. An alternative method; a control system (18) for controlling an emitter system (40) and a detector system (42); and an inspection system (14) comprising a control system (18), an emitter system (40) and a detector system (42), are also provided.