Automatic Value Label Examination Using Dual-Stage Luminescence Imaging
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Solution Overview
Problem
Existing methods for automatically verifying the authenticity of postage stamps with luminescent areas face challenges in balancing high-speed processing with the need to prevent damage from intense radiation, leading to reduced throughput and increased costs due to low contrast between luminescent backgrounds and codes.
Innovation Solution
A two-stage imaging method where the surface of mail items is first illuminated with daylight-like lighting to detect the presence of luminescent areas, followed by specific wavelength illumination to capture and verify luminescent patterns, allowing for increased speed and accuracy without damaging the items, and incorporating OCR for value recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-energy radiation is used to intensively excite luminescence for reliable code reading, then measurement precision is improved, but object-affected harmful factors increase due to overheating and damage risk
Solution Approach 1:
The patent uses periodic action by implementing a two-stage illumination process: first with low-energy daylight-like lighting for initial detection, then with high-energy radiation only when needed for pattern verification. This temporal separation allows high measurement precision when required while minimizing harmful radiation exposure overall.
Solution Approach 2:
The patent applies preliminary action by first using low-energy illumination to detect the presence of luminescent areas and identify their locations before employing high-energy radiation. This preliminary detection step filters out false positives and ensures high-energy radiation is only applied to relevant areas, reducing overall damage risk.
2Object-affected harmful factors
If low irradiation intensity is used to prevent damage, then object-affected harmful factors are reduced, but measurement precision decreases due to low luminescence contrast
Solution Approach 1:
The system periodically alternates between low-energy and high-energy illumination stages. The low-energy stage maintains minimal damage while the high-energy stage, applied selectively, restores measurement precision when pattern verification is needed.
Solution Approach 2:
Low-energy illumination performs preliminary detection of luminescent areas, allowing the system to identify which specific areas require high-energy illumination for detailed pattern analysis, thus maintaining precision only where necessary.
3Productivity
If high throughput speed is required for mail sorting, then productivity is improved, but device complexity increases due to need for multiple sorting machines
Solution Approach 1:
The patent merges two different illumination functions (low-energy detection and high-energy verification) into a single sorting machine with a dual-stage illumination system. This consolidation allows one machine to perform the work of multiple simpler machines, increasing throughput without proportionally increasing device complexity.
Solution Approach 2:
The sorting machine is designed with multi-functionality, capable of performing both initial luminescence detection and detailed pattern verification using different illumination modes. This universal design eliminates the need for separate specialized machines, improving productivity while controlling 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
This approach enhances the speed and reliability of authenticity checks while minimizing radiation exposure, allowing for higher throughput without compromising the integrity of mail items, and reduces the need for multiple sorting machines.
Implementation Method 1
irradiating the postage stamp with light containing wavelengths from a second spectral range, this light being suitable for stimulating the luminescence of the luminescent printing ink
Implementation Method 2
The luminescent property cannot be seen with the human eye under daylight-like lighting. However, a value can always be seen with the human eye under daylight-like lighting.
Data Source
AI summary
The invention relates to a method for the automatic examination of the genuineness of value-indicating stamps and indicia comprising a luminescent area, the stamp or indicium being applied to the surface of a mail item. The surface of the item is lighted with light of a wavelength of a spectral range, a first image of the surface of the item is recorded by means of a camera system and said first image is evaluated with respect to the location of stamps or indicia applied thereto on the surface of the item. The surface of the item is then lighted with light of a wavelength of a second spectral range, said light being suitable to excite luminescence of the luminescent ink, and a second image of the surface of the item is recorded under this light by means of a second camera system, said second image being evaluated with respect to the location of luminescence. The two evaluations are compared with each other with respect to the criterion of the presence of luminescence in the location or in the locations to which stamps or indicia according to the evaluation of the first image are present, only those stamps or indicia being examined further in the following steps which were detected to show luminescence. An image section or image sections of the second image is/are then defined for the location/locations in which the presence of stamps or indicia were detected, said image section or said image sections being evaluated with respect to the determination of location and geometry of the luminescence pattern of every stamp or indicium recognized on the surface of the item for which the presence of luminescence was recognized. A comparison of the evaluation of the image section or image sections with stored luminescence patterns will lead, when these match, to a decision on the genuineness of every stamp or indicium.