Dome Illuminator Asymmetric Tilt for Shiny Surface Reflection Elimination
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Solution Overview
Problem
Existing machine vision systems face challenges in reading ID codes on shiny, rounded surfaces due to reflection issues and the inability to simultaneously use multiple illumination sources effectively, which affects image acquisition time and accuracy.
Innovation Solution
A vision system camera with a dome illuminator that includes a diffuse inner surface with light-filtering structures, such as concentric strips or rings, to create a fringe pattern on shiny surfaces and a secondary projecting illuminator for matte surfaces, allowing for uniform light distribution and avoidance of camera reflection, enabling ID code decoding and shape inspection regardless of surface properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional illuminator is used to illuminate the scene, then the ID codes can be imaged, but camera reflections appear on shiny rounded surfaces creating black holes or stripes that obscure the code
Solution Approach 1:
The dome illuminator is tilted at an asymmetric angle (approximately 15 degrees) relative to the optical axis, creating an asymmetric illumination geometry that positions the camera reflection outside the field of view while maintaining effective illumination of the target surface
Solution Approach 2:
A diffuse dome structure acts as an intermediary between the light source and the target surface, scattering the illumination to create diffuse lighting that reduces specular reflections while the tilt angle further positions reflections away from the camera view
2Illumination intensity
If multiple illumination sources are used to improve lighting coverage, then illumination uniformity improves, but the system complexity increases
Solution Approach 1:
The dome illuminator structure serves multiple functions simultaneously: it houses multiple illumination sources, provides diffuse scattering through its inner surface, creates the fringe pattern through light-filtering structures, and the tilt angle mechanism manages reflections, eliminating the need for separate components for each function
Solution Approach 2:
Multiple illumination sources are merged into a single dome structure with a common diffuse inner surface and shared tilt mechanism, combining what would otherwise be separate illumination systems into one integrated unit that achieves uniform illumination without proportionally increasing system complexity
3Object-affected harmful factors
If the dome illuminator is tilted to avoid camera reflections, then reflection elimination improves, but the optical alignment becomes more complex
Solution Approach 1:
The dome illuminator is deliberately tilted at an asymmetric angle (approximately 15 degrees) relative to the optical axis, creating an asymmetric illumination geometry that positions the camera reflection outside the field of view while maintaining effective illumination of the target surface
Solution Approach 2:
The tilted dome structure integrates multiple functions: it provides diffuse illumination, creates the fringe pattern through light-filtering structures, and the tilt angle simultaneously manages reflections, reducing the need for separate reflection-mitigation components
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 solution allows for accurate imaging and decoding of ID codes on various surfaces, including shiny and curved surfaces, by eliminating reflection and enabling simultaneous use of multiple illumination sources, improving image acquisition time and accuracy.
Implementation Method 1
A dome illuminator with a diffuse inner surface is provided to the camera assembly
Implementation Method 2
The dome illuminator has two systems to create the pattern on an object, including a diffuse illuminator for substantially specular/shiny object surfaces and a secondary, projecting illuminator for matte/diffusive object surfaces. The diffuse illuminator includes a set of light-filtering structures on its inner surface
Implementation Method 3
The dome illuminator can be tilted to a predetermined angle relative to vertical (for example approximately 15 degrees) to avoid the reflection of the camera optics aperture
Data Source
AI summary
This invention provides an illumination assembly that is typically attached to the front end of a vision system camera assembly, adapted to generate an illumination pattern onto an object, which allows the vision system process(or) to perform basic shape inspection of the object in addition to feature detection and decoding. A dome illuminator with a diffuse inner surface is provided to the camera assembly with a sufficient opening side to surround the object. The dome illuminator has two systems to create the pattern on an object, including a diffuse illuminator for specular/shiny object surfaces and a secondary, projecting illuminator for matte/diffusive object surfaces. The diffuse illuminator includes a set of light-filtering structures on its inner surface—for example concentric strips or rings that allow projection of a ringed fringe pattern on an (e.g. shiny/specular) object. The fringes can additionally be generated in a given a certain wavelength and/or visible color.