Wavelength-Selective Aperture for Imaging Resolution and Light Efficiency
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Solution Overview
Problem
Reverse vending machines face challenges in accurately recognizing different markings on objects, such as bar codes and deposit marks, due to varying resolutions and unknown distances, which require adjustments in camera depth of field and light exposure.
Innovation Solution
A system with a diaphragm having a central area that transmits radiation of one wavelength and a surrounding area that blocks a second wavelength, allowing for adjustable resolution by switching between light sources, ensuring sufficient sharpness and efficient light use for both coarse and fine details.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a large aperture is used to admit more light for efficient illumination, then light efficiency is improved, but resolution for fine details deteriorates
Solution Approach 1:
The aperture is segmented into two distinct areas: a first area that transmits both first and second wavelengths, and a second area that blocks the second wavelength. This segmentation allows different aperture configurations for different wavelengths, enabling the system to optimize between light efficiency and resolution by selecting which wavelength to use based on the marking characteristics
Solution Approach 2:
The aperture configuration is made dynamic by switching between different wavelengths (first and second wavelengths) based on the marking type. The system can adaptively change which wavelength is transmitted through the aperture, effectively changing the aperture's functional characteristics to match the imaging requirements
2Measurement precision
If a small aperture is used to increase resolution for fine details, then resolution is improved, but light efficiency deteriorates
Solution Approach 1:
The system changes the wavelength parameter to resolve the contradiction. By switching to the first wavelength when high light efficiency is needed, the system can use a larger effective aperture configuration. By switching to the second wavelength when high resolution is needed, the system can use a smaller effective aperture configuration, thus resolving the trade-off through parameter changes
3Adaptability or versatility
If the camera depth of field is increased to cover unknown distances, then adaptability to distance is improved, but measurement precision for fine details deteriorates
Solution Approach 1:
The system uses wavelength as a controllable parameter to resolve the depth of field vs. precision contradiction. By selecting the second wavelength for fine markings, the system achieves higher precision even at specific distances. By selecting the first wavelength for coarse markings, the system maintains adequate precision across a broader distance range, thus adapting to different scenarios through parameter selection
4Measurement precision
If multiple light sources are used to compensate for reduced light from smaller aperture, then resolution is improved, but device complexity increases
Solution Approach 1:
Instead of adding multiple light sources, the system changes the wavelength parameter to resolve the contradiction. By switching to the first wavelength when high light efficiency is needed, the system maintains adequate resolution without requiring additional light sources. This parameter-based solution avoids increasing device complexity while still achieving the desired resolution
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 recognition of both coarse and fine markings by adjusting aperture size based on wavelength, ensuring sharp images regardless of object distance and light source efficiency, effectively addressing the challenges of varying markings and distances.
Implementation Method 1
The aperture includes: a first, central area adapted to transmit radiation of at least the first wavelength(s) and the second wavelength(s); and a second area surrounding said first area, which second area is adapted to block (or stop or shield) radiation of the second wavelength(s), but transmit radiation of the first wavelength(s)
Data Source
AI summary
A system for imaging an object, the system including: a detection zone; a first unit adapted to selectively emit radiation of at least one first wavelength and radiation of at least one second, different wavelength for at least partly illuminating the object in the detection zone; a second unit adapted to capture at least partial images of the illuminated object; and an aperture placed in an optical path between the detection zone and the second unit. The aperture includes: a first, central area adapted to transmit radiation of at least the first wavelength(s) and the second wavelength(s); and a second area surrounding said first area, which second area is adapted to block radiation of the second wavelength(s), but transmit radiation of the first wavelength(s). Also, an imaging method, and use of a diaphragm in a reverse vending machine.