Off-axis dual-sensor vision system for DPM code reading
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing machine vision systems face challenges in reading Direct Part Marking (DPM) codes on shiny, rounded surfaces due to reflection issues and the inability to effectively utilize multiple illumination sources simultaneously, which hinders accurate image capture and decoding.
Innovation Solution
A handheld vision system with a dual-imaging configuration, featuring an off-axis imaging system with diffusive illumination and a concave diffuser, and an on-axis imaging system with polarized illumination, which optimizes contrast and minimizes camera reflection, allowing for superior reading and decoding of small codes on shiny surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional on-axis imaging system is used with single illumination source, then device complexity is reduced, but code contrast and decodability deteriorate on shiny rounded surfaces due to camera reflection
Solution Approach 1:
The imaging system is segmented into two separate imaging systems: an on-axis imaging system and an off-axis imaging system. Each system captures images from different angles, allowing the reflection-free off-axis images to be combined with the on-axis images to eliminate camera reflection artifacts while improving code contrast and decodability
Solution Approach 2:
Images from the on-axis and off-axis imaging systems are merged through image blending techniques. The off-axis image, which lacks camera reflection, is combined with the on-axis image to produce a final image that maintains high code contrast while eliminating the black hole artifact, thereby improving measurement precision
2Measurement precision
If multiple illumination sources are used simultaneously to improve code visibility, then code contrast is improved, but the ability to capture images from multiple sources simultaneously deteriorates due to reflection interference
Solution Approach 1:
The system transitions from using multiple illumination sources at the same angle to using illumination sources from different spatial dimensions (angles). The off-axis illumination source illuminates the code from an angle that prevents camera reflection, while the on-axis source provides direct illumination. This angular dimensionality allows both sources to be used simultaneously without reflection interference, improving both code visibility and acquisition speed
3Measurement precision
If off-axis imaging system is used to minimize camera reflection, then code decodability is improved, but device complexity increases due to dual-sensor configuration
Solution Approach 1:
The dual-imaging system is designed with universal functionality where both the on-axis and off-axis imaging systems can operate independently or in combination. The system can switch between using only on-axis images, only off-axis images, or blended images depending on the specific application requirements, thereby managing device complexity while maintaining improved code decodability
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 dual-imaging system enhances code contrast and decodability by positioning the camera reflection outside the code area and enables simultaneous use of multiple illumination sources, improving acquisition time and accuracy.
Implementation Method 1
a diffusive illumination source with an emitter in the form of a concave surface, such as a semi-cylinder or dome
Implementation Method 2
an on-axis imaging system that is typically standard in configuration, and can be used, for example, with a polarized illumination system
Data Source
AI summary
This invention overcomes disadvantages of the prior art by providing, vision system, typically in the form of a handheld ID reader, which can include two imaging systems, a first imaging system that is off-axis and a second imaging system that is on-axis. The on-axis imaging system is typically standard in configuration, and can be used, for example, with a polarized illumination system. The off-axis imaging system is intended to minimize the camera reflection footprint on a (typically rounded) shiny object to enhance reading of small feature sets (e.g. DMP codes). The off-axis imaging system includes a diffusive illumination source with an emitter in the form of a concave surface, such as a semi-cylinder or dome. Combining images from the two imaging systems allows the contrast of the imaged feature set to be optimized, and provide superior reading and decoding of small codes on shiny rounded surfaces—such as DPM codes.