Multi-chromatic Imaging System with Synchronized LED Illumination
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Solution Overview
Problem
Existing multi-chromatic imaging systems for product flows, such as in bulk sorting, are costly and not optimized for using multiple line array detectors effectively, limiting their ability to provide accurate characterization of products based on multiple characteristics with reduced sensitivity to the angle of incidence.
Innovation Solution
A multi-chromatic imaging system utilizing multiple unfiltered line array detectors receiving reflected radiation through a single lens, with sequential illumination from semiconductor LEDs at different wavelengths, and a control unit to synchronize illumination with the product flow, allowing for improved detection and characterization of products across multiple wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple filtered detectors are used for multi-chromatic imaging, then detection accuracy is improved, but system cost and complexity increase
Solution Approach 1:
The patent combines multiple unfiltered line array detectors to simultaneously capture multiple wavelengths, replacing the need for multiple filtered detectors. This merging approach maintains multi-chromatic detection capability while reducing system complexity and cost by eliminating the need for separate filters and detectors for each wavelength.
Solution Approach 2:
The unfiltered line array detectors serve multiple functions by detecting multiple wavelengths simultaneously without requiring wavelength-specific filters. Each detector acts as a universal detector that can capture information across the entire spectrum, thereby simplifying the overall system architecture.
2Loss of information
If multiple filtered detectors are used for multi-chromatic imaging, then product characterization is improved, but device complexity increases
Solution Approach 1:
Multiple unfiltered line array detectors are merged to capture complete spectral information for product characterization. By combining the data from multiple detectors that each capture the full spectrum, the system achieves comprehensive product characterization without requiring complex filtered detector arrangements.
Solution Approach 2:
The system uses sequential illumination with different wavelengths and captures images at different time points, then combines these temporal sequences to achieve multi-chromatic characterization. This periodic illumination approach allows complete product characterization while using simpler unfiltered detectors.
3Device complexity
If mono-chromatic imaging is used, then system simplicity is maintained, but detection accuracy and robustness against angle of incidence deteriorates
Solution Approach 1:
The patent merges multiple unfiltered line array detectors to capture multi-chromatic information, achieving robust detection that is less sensitive to angle of incidence while maintaining relative system simplicity. The combination of multiple detectors provides redundant information that compensates for angular variations.
Solution Approach 2:
The system changes the spectral parameter by using multiple detectors sensitive to different wavelength ranges, thereby improving detection accuracy and angular robustness. By analyzing products across multiple spectral parameters simultaneously, the system overcomes the limitations of mono-chromatic imaging without significantly increasing complexity.
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 achieves enhanced detection and characterization of products with reduced cost by using multiple line array detectors and synchronized illumination, improving accuracy and robustness against angle of incidence variations, enabling effective multi-chromatic imaging in product flows.
Implementation Method 1
detecting reflected radiation from product P in the product flow F
Implementation Method 2
a detector unit (15) for detecting reflected illumination from product P
Implementation Method 3
the first and second illumination sources 5a, 5b comprise semiconductor illumination sources, here LEDs arranged in rows
Data Source
Figure 1~2(a)
Figure 2(b)~3
Figure 4(a)~4(b)
AI summary
An imaging system for and method of imaging product in a product flow (F), the system comprising: an illumination unit for illuminating product in the product flow with illumination at first and second, different wavelengths or ranges of different wavelengths; a detector unit (15) for detecting reflected illumination from product in the product flow, wherein the detector unit comprises first and second line array detectors, the line array detectors (17a, 17b) each comprising a plurality of pixel elements and extending as lines across a width of the product flow, one line downstream of the other, whereby product passing a pixel element of the first line array detector passes a corresponding pixel element of the second line array detector; a control unit for triggering the first and second illumination sources to flash sequentially at a scan rate corresponding to the flow rate of the product flow; and an image processing unit for successively reading the pixel lines of the first and second line array detectors and constructing images of the product at each of the illumination wavelengths or ranges of illumination wavelengths.