Ceramic Honeycomb Defect Inspection via Multi-Angle Illumination
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Solution Overview
Problem
Existing methods for inspecting defects on the outer surface of ceramic honeycomb structural bodies, particularly the end face, often result in false detection of normal surface irregularities as defects due to the challenges in distinguishing between defects and normal features under oblique illumination.
Innovation Solution
An apparatus and method utilizing multiple illumination elements positioned at different angles around the image capturing part to capture images from various directions, generating minimum or maximum luminance image data to enhance defect detection by superimposing shadow regions and reducing false positives through threshold-based determination processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If oblique illumination is used to enhance defect visibility, then defect detection capability is improved, but false detection of normal surface irregularities increases
Solution Approach 1:
The illumination system is segmented into multiple independent illumination elements arranged at different angular positions around the inspection target. Each illumination element illuminates the target from a different angle, and the images captured under each illumination condition are processed separately and then synthesized to distinguish defects from normal surface irregularities.
Solution Approach 2:
The inspection system transitions from single-angle illumination to multi-angle illumination by arranging illumination elements in a circular array around the target. This adds the angular dimension to the illumination geometry, enabling the system to capture surface features from multiple perspectives and differentiate between defects and normal irregularities based on their angular illumination responses.
2Measurement precision
If multiple illumination elements are added to capture images from various directions, then defect detection accuracy is improved, but device complexity increases
Solution Approach 1:
Multiple illumination elements are merged into a single circular array structure that surrounds the inspection target. The images captured by multiple illumination elements are merged through image processing to generate a comprehensive defect detection result, reducing the need for separate illumination systems for each angle.
Solution Approach 2:
The circular array of illumination elements serves multiple functions: each element can independently illuminate the target from a different angle, and collectively they provide comprehensive coverage for detecting various types of surface defects. The same illumination system is used for both enhancing defect visibility and characterizing normal surface irregularities.
3Measurement precision
If normal surface irregularities are illuminated to be visible, then complete surface inspection is achieved, but distinction between defects and normal features becomes more difficult
Solution Approach 1:
The system captures images under multiple illumination angles and uses image processing to compare the responses of different surface features. Normal surface irregularities exhibit consistent illumination patterns across different angles, while defects show distinctive shadow patterns. This feedback mechanism enables automatic differentiation between defects and normal features.
Solution Approach 2:
The image processing generates different luminance values for different surface features based on their illumination responses. Defects appear as dark regions with specific luminance characteristics that differ from normal surface irregularities, enabling visual and automated distinction between the two types of features.
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 reliably detects defects on the ceramic honeycomb structural body's end face while minimizing false detection of normal surface irregularities, ensuring accurate inspection results.
Implementation Method 1
one or more illumination parts including a four or more illumination elements configured to irradiate the inspection target region with illumination light obliquely at an identical irradiation angle in respective irradiation directions different from each other
Data Source
AI summary
A plurality of illumination elements configured to irradiate an inspection target region with illumination light obliquely at an identical angle in respective directions different from each other and equiangularly spaced from each other around an image capturing part are sequentially turned on and off. The image capturing part generates a plurality of pieces of captured image data by capturing an image of the target region in a normal direction when each of the plurality of illumination elements is turned on. A determination image generation part generates minimum luminance image data in which a minimum value among luminance values of the plurality of pieces of captured image data at an identical pixel position is set as a luminance value at the pixel position, and then generates determination image data based on the minimum luminance image data. A defect determination part determines existence of a defect based on the determination image data.