Transparent Object Inspection Using Dark-Background Scatter Detection
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Solution Overview
Problem
Existing methods for inspecting transparent objects are inefficient and prone to human error, particularly in identifying defects within the object's structure, and are not suitable for automatic inspection of large quantities of similar objects.
Innovation Solution
An inspection system comprising imaging units, light sources, and dark backgrounds arranged to illuminate and capture images of transparent objects from an oblique angle, detecting scattered light indicative of defects using a computing unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual inspection methods are used, then flexibility in inspection is maintained, but inspection accuracy and reliability deteriorate due to human error
Solution Approach 1:
The patent replaces manual visual inspection with an automated optical inspection system comprising imaging units, light sources, and computing units. The system automatically captures images of transparent objects and processes them to detect defects, eliminating human error while maintaining inspection reliability.
2Measurement precision
If bright background illumination is used, then defect visibility is improved, but measurement precision deteriorates due to inaccurate identification of opaque marks
Solution Approach 1:
The patent inverts the traditional illumination approach by using dark background illumination instead of bright backgrounds. The imaging units capture images against dark backgrounds, making defects appear as bright spots or anomalies. This inversion improves measurement precision by eliminating the inaccuracies associated with bright background illumination while maintaining defect visibility.
3Productivity
If conventional imaging is used, then simplicity of the system is maintained, but productivity deteriorates due to inability to efficiently inspect large quantities of objects
Solution Approach 1:
The patent employs a multi-functional inspection system where imaging units, light sources, and computing units work together to perform automated defect detection. The system can inspect large quantities of transparent objects efficiently by automatically capturing and processing multiple images, thereby increasing productivity while managing system complexity through integrated design.
4Measurement precision
If oblique angle imaging is used, then defect detection capability is improved, but device complexity increases due to specific arrangement requirements
Solution Approach 1:
The patent applies oblique angle imaging specifically at the inspection position where defects need to be detected. The imaging units are positioned at oblique angles relative to the transparent objects to optimize defect visibility. This localized application of oblique imaging improves defect detection capability while minimizing the overall complexity of the system arrangement.
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 efficient, automatic detection of defects in transparent objects by capturing images with dark backgrounds, reducing human error and enabling high-throughput inspection.
Implementation Method 1
The scattered light, being deflected from a defect in the transparent object, is indicative of said defect
Implementation Method 2
The at least one imaging unit is configured and arranged relative to the inspection position to capture one or more images of the transparent object from a second side of the transparent object
Data Source
Figure 1a~1c
Figure 2a~2b
Figure 2c~2d
AI summary
The invention pertains to an inspection system for detecting defects (11) in a transparent object (10), the system comprising at least one imaging unit (108), one or more light sources (109) and at least one dark background (110) that are arranged around an inspection position for inspection of the transparent object. The light sources are configured emit light (119) to illuminate the transparent object at least from a first side of the object when the object is positioned at the inspection position. The imaging unit is configured and arranged relative to the inspection position to capture one or more images (12) of the transparent object from a second side of the object when the object is positioned at the inspection position, and configured to generate image data. The dark background is arranged so that the inspection position lies between the at least one imaging unit and the at least one dark background. The system comprises a computing unit configured to receive the image data and to detect, in the image data, one or more indications of scattered light (109') deflected from a defect in the transparent object. The invention also pertains to a method for detecting defects in a transparent object using such a system.