Illumination Angle Control for Surface Unevenness Imaging

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Solution Overview

Problem

It is challenging to capture high-contrast images of objects with fine surface unevenness due to difficulties in managing diffuse reflection, which reduces image contrast.

Innovation Solution

An image capturing system that adjusts the irradiation angle range based on measured unevenness data from a surface, using a control means to determine the optimal irradiation angle range for the illumination means, thereby reducing diffuse reflection and enhancing specular reflection, allowing for higher contrast image capture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional illumination is used to capture surface unevenness, then the imaging process is simple, but the image contrast is low due to diffuse reflection

Engineering Contradiction:
Improveimage contrastVSAvoidillumination control complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by adjusting the irradiation angle range of the illumination light based on the measured inclination distribution of surface unevenness. By changing the illumination parameters (angle range) to match the surface characteristics, the system enhances specular reflection and reduces diffuse reflection, thereby improving image contrast without requiring complex hardware modifications

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback by measuring the surface unevenness inclination distribution first, then using this measurement information to determine the optimal irradiation angle range. This closed-loop feedback mechanism allows the system to adapt the illumination conditions based on actual surface characteristics, resolving the contradiction between simple illumination and high image contrast

Inventive Principle:
Principle #23Feedback

2Area of stationary object

If the irradiation angle range is widened to illuminate the entire surface, then coverage is improved, but diffuse reflection increases and reduces image contrast

Engineering Contradiction:
Improveillumination coverageVSAvoidimage contrast
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent applies local quality by tailoring the irradiation angle range to the specific inclination characteristics of different regions of the surface. Instead of using a uniform wide-angle illumination, the system adjusts the illumination angles locally according to the measured unevenness distribution, maintaining adequate coverage while optimizing contrast for each region

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system dynamically changes the irradiation angle range parameters based on the measured surface inclination distribution. By adjusting these parameters to match the surface geometry, the patent achieves both sufficient coverage and high image contrast, resolving the contradiction between area coverage and measurement precision

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If multiple illumination angles are used to reduce diffuse reflection, then image contrast improves, but the imaging process becomes more complex

Engineering Contradiction:
Improveimage contrastVSAvoidimaging time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by measuring the surface unevenness inclination distribution before the actual imaging process. This pre-measurement allows the system to determine the optimal single irradiation angle range in advance, eliminating the need for time-consuming multi-angle imaging while still achieving high contrast results

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

By using the pre-measured inclination distribution to determine the optimal irradiation angle range, the system changes the illumination parameters once based on surface characteristics. This single optimized setting achieves high image contrast without requiring multiple imaging passes, thus reducing imaging time while maintaining measurement precision

Inventive Principle:
Principle #35Parameter changes

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

The system effectively captures high-contrast images by controlling the irradiation angle range, improving the visibility of fine unevenness patterns on object surfaces, even those with low specular reflection materials.

Implementation Method 1

enhancing specular reflection, allowing for higher contrast image capture

Methodology Applied
Scientific EffectSpecular reflection: Reflection

Implementation Method 2

reduce diffuse reflection by adjusting an irradiation angle range

Methodology Applied
Scientific EffectDiffuse reflection: Reflection

Data Source

PatentEP3926575B1Information processing device, method and program
Publication Date: 2024.06.05 NEC CORP
  • EP3926575B1 patent drawingFigure 1
  • EP3926575B1 patent drawingFigure 2
  • EP3926575B1 patent drawingFigure 3

AI summary

An information processing device, to be used in an image capturing device that illuminates an object by an illumination means and captures reflected light from the object as a reflection image by a capturing means, includes a determination means for determining an irradiation angle range for irradiating the object by the illumination means, on the basis of two types of inclination statistic values that are values corresponding to the inclination distribution of the unevenness existing on a surface of the object.