Multi-Sensorial Surface Inspection Using Stroboscopic Line Camera

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Solution Overview

Problem

Current surface inspection technologies are costly and inefficient for products with complex, three-dimensional topologies due to the need for multiple lighting/camera arrangements and high computational power, especially when inspecting moving products with varying surface structures.

Innovation Solution

A method using a stationary line camera with an increased line rate and stroboscopic lighting configurations, where different lighting configurations are applied synchronously with the line cycle to capture interlaced multi-sensor image lines, allowing for defect detection without separate color channels and reducing costs by using fewer light sources and monochromatic cameras.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple lighting/camera arrangements are used to inspect different surface regions, then detection capability for various defects is improved, but system cost and complexity increase significantly

Engineering Contradiction:
Improvedefect detection capabilityVSAvoidsystem cost
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The inspection system divides the surface into multiple regions with different topological characteristics (flat, inclined, concave, convex) and assigns specific lighting configurations to each region. Instead of using multiple separate camera systems, the patent segments the lighting arrangements to match different surface regions, reducing overall system complexity while maintaining detection capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A single line camera system is designed to perform multiple inspection functions by capturing images under different lighting configurations. The same camera records surfaces under various lighting conditions (diffuse, directed, transmitted), enabling it to detect different defect types across diverse surface topologies without requiring separate specialized cameras for each function.

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

2Measurement precision

If multiple lighting configurations are applied simultaneously to capture comprehensive surface information, then detection accuracy improves, but computational requirements and system cost increase

Engineering Contradiction:
Improvedetection accuracyVSAvoidcomputational power
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The system applies lighting configurations in a periodic, sequential manner rather than simultaneously. Different lighting arrangements (diffuse, directed, transmitted) are cycled through in sequence during the inspection process, allowing the single line camera to capture comprehensive surface information over time without requiring multiple cameras or excessive computational power for simultaneous multi-channel processing.

Inventive Principle:
Principle #19Periodic action

3Measurement precision

If high lateral resolution is used to detect defects on large products, then detection precision improves, but the number of pixels per line and system cost increase

Engineering Contradiction:
Improvedefect detection precisionVSAvoidnumber of pixels per line
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The system applies different lighting configurations tailored to specific local surface regions rather than using uniform high-resolution imaging across the entire product. By locally adapting lighting to match surface topology (flat, inclined, concave, convex regions), the system maintains detection precision without requiring excessive pixels per line throughout the entire image field.

Inventive Principle:
Principle #3Local quality

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 robust detection of aesthetic and physical defects on complex surfaces with reduced costs and computational requirements, adapting to local surface properties for improved fault detection sensitivity and reduced false positives.

Implementation Method 1

A respective different lighting configuration from a number of N lighting configurations exposes the surface to be tested stroboscopically, synchronized with the line cycle

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

A respective different lighting configuration from a number of N lighting configurations exposes the surface to be tested stroboscopically, synchronized with the line cycle

Methodology Applied
Scientific EffectStroboscopic effect: Stroboscopic Effect

Data Source

PatentEP1742041B1Cost-effective multi-sensorial surface inspection
Publication Date: 2013.10.23 BAUMER INSPECTION
  • EP1742041B1 patent drawingFigure 1
  • EP1742041B1 patent drawingFigure 2
  • EP1742041B1 patent drawingFigure 3

AI summary

A multi sensor surface inspection procedure uses a line camera (18) orthogonal to the surface (10) with line rate at N times higher than the geometric size of the defect (14) to be detected and uses synchronised stroboscopic illumination using a lighting configuration selected from M light sources (20-26). Independent claims are included for surface inspection equipment implementing the procedure and for the use of a monochromatic camera and different spectrum light sources.