Container Inspection System Using Tapered Light Director
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Solution Overview
Problem
Conventional container inspection systems in production plants face inaccuracies in detecting defects on cylindrical containers due to mirror-like surfaces, leading to hundreds of thousands of defective containers being manufactured before defects are noticed, resulting in significant scrap costs.
Innovation Solution
A container inspection system that uses a light source with a light director element to create a tapering field of illumination at steep angles, combined with tilted cameras and a computing system for image analysis, to differentiate between reflections and actual defects on the container surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional automated inspection systems use standard illumination and camera positioning, then the system can capture images of container surfaces, but the mirror-like quality of cylindrical container surfaces causes light reflections from adjacent containers to appear in the images, making it difficult to distinguish reflections from actual defects
Solution Approach 1:
The illumination system provides non-uniform lighting with different incident angles across different regions of the container surface. By creating localized illumination zones with specific angular characteristics, the system ensures that each point on the container surface is illuminated from a unique angle, preventing coherent reflections from adjacent containers while maintaining uniform coverage of the entire surface.
Solution Approach 2:
The system employs asymmetric illumination geometry where light sources are positioned at multiple angles relative to the container axis, rather than using symmetric radial illumination. This asymmetric arrangement ensures that reflection paths from adjacent containers do not converge on the camera sensor, effectively eliminating spurious reflections while maintaining comprehensive surface coverage.
2Reliability
If an operator performs periodic visual inspection by sampling containers, then the inspection process is simple and low-cost, but hundreds of thousands of defective containers may be manufactured before a defect is noticed
Solution Approach 1:
The system replaces manual operator inspection with an automated optical inspection system that uses multiple cameras and specialized illumination to continuously capture and analyze images of container surfaces at production line speed. This substitution enables 100% inspection coverage rather than periodic sampling, dramatically improving defect detection reliability while maintaining high productivity.
Solution Approach 2:
The system introduces an intermediate image processing and analysis stage between the container surface and the final defect determination. Multiple cameras capture images that are then processed through algorithms that distinguish actual defects from illumination artifacts and reflections, providing reliable automated defect detection without requiring direct human intervention at each inspection point.
3Extent of automation
If multiple cameras are positioned to capture images of container surfaces, then automated visual inspection can be performed, but the system suffers from inaccuracies due to light reflections from adjacent containers
Solution Approach 1:
The system varies multiple illumination parameters simultaneously, including incident angle, polarization state, and intensity distribution across the container surface. By dynamically changing these parameters rather than using fixed illumination conditions, the system creates distinct optical signatures for different surface features, enabling cameras to differentiate between actual defects and reflections from adjacent containers.
Solution Approach 2:
The system adds angular dimensionality to the illumination geometry by positioning light sources at multiple angles around the container rather than using single-directional lighting. This multi-angular illumination approach creates dimensionally diverse light paths that prevent coherent reflections from entering the camera, while still providing complete surface coverage through the combined fields of view of multiple cameras.
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 detects various defects on container surfaces, including physical and design-related issues, at high speeds, reducing scrap rates and improving inspection accuracy compared to conventional methods.
Implementation Method 1
light that illuminates the exterior surfaces of a container may reflect off of numerous surfaces (including surfaces of adjacent containers on the conveyor), which causes reflections of portions of the adjacent containers to appear in images of the exterior surfaces of the container under inspection
Implementation Method 2
The container inspection system further includes a light director element that is configured to receive the light emitted from the light source and illuminate an exterior surface of a sidewall of a container (while the container is being transported by a conveyor) when the container enters an inspection region
Data Source
AI summary
A container inspection system is described herein. The container inspection system includes a light source that emits a flash of light when a container is detected as being in an inspection region. The container inspection system further includes a light director element that receives a portion of the flash of light and forms a tapering field of light that illuminates an exterior surface of a sidewall of the container when the container is in the inspection region. The container inspection system further comprises a camera that generates an image of the exterior surface when such surface is illuminated by the tapering field of light. A computing system receives the image and outputs an indication as to whether or not the container is defective based upon the image.