Transparent Illumination Unit for Calibration-Free Image Inspection

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Solution Overview

Problem

Conventional image inspection methods require calibration between the image capturing unit and the illumination device, which is inconvenient and time-consuming.

Innovation Solution

An image inspection apparatus and method that uses a transparent illumination unit with a light-emitting surface capable of selecting a light-emitting position and controlling the radiation direction, along with a control unit to identify the light-emitting position and calculate distances without the need for calibration between the image capturing unit and the illumination device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If calibration between the image capturing unit and the illumination device is performed, then inspection accuracy is improved, but operation convenience deteriorates due to the time-consuming calibration process

Engineering Contradiction:
Improveinspection accuracyVSAvoidoperation convenience
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system performs self-calibration by automatically identifying the relative position between the image capturing unit and illumination device through image processing. The control unit calculates the relative position based on captured images without requiring manual calibration operations, making the system self-configuring and eliminating the time-consuming manual calibration process while maintaining inspection accuracy

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the mechanical calibration process with an optical and computational approach. Instead of manually adjusting physical positions, the system uses the image capturing unit to capture the illumination device's position and employs image processing algorithms to calculate relative coordinates, substituting mechanical adjustment with optical measurement and computational geometry

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

2Adaptability or versatility

If a fixed illumination device configuration is used, then device complexity is reduced, but adaptability deteriorates due to inability to adjust radiation solid angle

Engineering Contradiction:
Improveradiation solid angle adjustmentVSAvoidillumination device configuration
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The illumination device incorporates a movable mirror that can be dynamically adjusted to change the radiation direction of light. This dynamic element allows the system to adapt the radiation solid angle and illumination patterns for different inspection scenarios, transforming a static illumination system into a flexible, reconfigurable one without substantially increasing overall device complexity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The illumination device is designed with multi-functionality, capable of performing multiple illumination patterns and radiation angles using a single device configuration. The movable mirror and controllable light source enable the same illumination device to serve various inspection requirements, eliminating the need for multiple specialized illumination devices

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

Enables image inspection without the necessity for calibration between the image capturing unit and the illumination device, allowing for flexible radiation solid angle settings and reducing the size of the illumination device.

Implementation Method 1

the control unit is configured to cause the illumination unit to radiate light to the object in a first direction and cause the light directed in the first direction to scan by changing the light-emitting position on the light-emitting surface

Methodology Applied
Scientific EffectLight radiation and scanning: Light

Implementation Method 2

an image capturing unit for capturing images of an object

Methodology Applied
Scientific EffectImage capture through light reflection: Reflection

Implementation Method 3

calculate a distance from the light-emitting surface to the measurement point on the basis of the identified light-emitting positions, the first direction and the second direction

Methodology Applied
Scientific EffectTriangulation distance calculation: Geometry

Data Source

PatentEP3531115B1Image inspection apparatus and image inspection method
Publication Date: 2023.07.05 OMRON CORP
  • EP3531115B1 patent drawingFigure 1
  • EP3531115B1 patent drawingFigure 2~3
  • EP3531115B1 patent drawingFigure 4~6

AI summary

The image inspection apparatus (1) includes an image capturing unit (10) which captures images of an object (W), a transparent illumination unit (20, 120, 220, 320), and a control unit (100). The illumination unit (20, 120, 220, 320) radiates light to the object (W) in a first direction and causes the light to scan and radiates light to the object (W) in a second direction and causes the light to scan. The image capturing unit (10) captures images of the object (W). The control unit (100) identifies a light-emitting position of the illumination unit (20, 120, 220, 320) when a measurement point (13) of the surface of the object (W) is illuminated from images of the object (W) captured, and calculates a distance to the measurement point (13) on the basis of the identified light-emitting position, the first direction and the second direction.