Non-Contact RPT Reader Using Optical Alignment
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Solution Overview
Problem
The existing contact-type Reflective Particle Tag (RPT) system requires physical contact with the tag for precise alignment, limiting its application to complex geometries and curved surfaces, and is not suitable for non-contact scenarios, which restricts its use in certain environments and increases inspection time.
Innovation Solution
A non-contact handheld imaging system with a read head assembly, including a camera, illuminators, and a rigid frame, that uses computational and compressive imaging sensing to quantify positional and angular alignment parameters, allowing for the authentication of reflective particle tags without physical contact, and is compatible with complex geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the reader is placed in contact with the flat frame for precise alignment, then measurement precision and reliability are improved, but ease of operation and adaptability to complex geometries deteriorate
Solution Approach 1:
The patent replaces the mechanical contact-based alignment system with an optical imaging system. The reader uses a camera and illuminators to capture images of the RPT from a distance, eliminating the need for physical contact and mechanical docking. This substitution allows for non-contact verification while maintaining measurement precision through computational imaging techniques.
Solution Approach 2:
The patent introduces an optical field as an intermediary between the reader and the RPT. Instead of direct mechanical contact, the system uses light to transmit information from the tag to the reader. The illuminators project light onto the RPT, and the camera captures the reflected light patterns, enabling alignment and verification without physical contact.
2Reliability
If the reader is placed in contact with the flat frame for precise alignment, then reliability is improved, but adaptability to complex geometries and curved surfaces deteriorates
Solution Approach 1:
The mechanical contact system is replaced with an optical imaging system that can accommodate various geometries. The camera and illuminators can be positioned at different distances and angles, allowing the reader to verify RPTs on flat surfaces, curved surfaces, and complex geometries without requiring physical contact or modification of the tag mounting surface.
Solution Approach 2:
The system transitions from a static, fixed-position contact mechanism to a dynamic, adjustable optical system. The reader can move freely in space, adjusting its position and orientation to optimize the imaging angle for different geometries. This dynamic capability enables adaptation to various surfaces while maintaining verification reliability.
3Measurement precision
If tightly collimated illumination beams and small aperture are used for precise alignment, then measurement precision is improved, but ease of operation and productivity deteriorate
Solution Approach 1:
The system uses rapid sequential imaging with multiple illuminators activated in different time intervals. The illuminators are turned on and off in a periodic sequence, capturing multiple images of the RPT from different illumination angles. This periodic action enables comprehensive verification while maintaining precision, and the rapid switching allows for efficient data collection that improves productivity.
Solution Approach 2:
The system maintains continuous verification capability by rapidly switching between multiple illuminators and capturing images in quick succession. This continuous action eliminates idle time between measurements, allowing the reader to verify multiple tags efficiently while maintaining the precision required for accurate authentication.
4Reliability
If contact-type RPT system is used for precise alignment, then reliability is improved, but loss of time due to manual handling and positioning increases
Solution Approach 1:
The manual mechanical handling and positioning process is replaced with an automated optical imaging system. The camera and illuminators automatically capture and analyze the RPT patterns without requiring manual intervention for positioning or alignment. This automation maintains verification reliability while dramatically reducing the time required for each inspection.
Solution Approach 2:
The system performs self-alignment and self-verification through automated image processing. The camera automatically captures the RPT pattern, and the processing software automatically analyzes the image to verify authenticity. This self-service capability eliminates the need for manual positioning and alignment operations, reducing inspection time while maintaining reliability.
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 enables rapid and precise authentication of reflective particle tags on complex surfaces, reduces inspection time, and enhances security by providing high-quality images without direct contact, while being resistant to counterfeiting and removal detection, and automates repetitive tasks.
Implementation Method 1
The RPT was developed to identify items that must be accounted for under international treaties. In most instances the tag, or RPT, is composed of an article with unique optical characteristics, e.g., specular hematite particles randomly dispersed in a clear, adhesive polymer matrix.
Data Source
AI summary
A reflective particle tag reader system includes a read head assembly having a camera, illuminators, and a rigid frame portion for supporting the camera and the illuminators. The illuminators illuminate a focal point located opposite the camera where a reflective particle tag is placed. A computer in data communication with the camera receives and store images of the reflective particle tag that are acquired by the camera. The computer is programmed to process video images and to quantify a positional alignment parameter and an angular alignment parameter of the reader with respect to the reflective particle tag. A rapid burst of image frames is obtained in response to the positional alignment and the angular alignment parameters being within a predetermined tolerance and identity of the reflective tag is established between a first image set and a second image set.