Dual-Window Imager with Proximity-Controlled Illumination
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Solution Overview
Problem
Existing point-of-transaction workstations with imager-based readers face performance issues due to the need for multiple imagers to achieve full coverage of indicia on three-dimensional products, leading to high costs and sluggish performance from internal auto-exposure delays.
Innovation Solution
A dual-window workstation with two solid-state imagers and an optical system that splits the field of view into multiple subfields, combined with a proximity system for real-time adjustment of illumination and exposure, reduces the number of imagers required and enhances processing performance without increasing complexity or cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple imagers are used to achieve full coverage of indicia on three-dimensional products, then reading reliability is improved, but device cost and complexity increase
Solution Approach 1:
The field of view of a single imager is divided into multiple subfields using optical splitters (beam splitters), allowing one imager to effectively cover multiple scanning zones that would otherwise require multiple separate imagers. This segmentation of the optical path enables full product coverage while reducing the number of imager components needed.
Solution Approach 2:
A single imager is designed to perform multiple functions by capturing indicia from different angles and positions through its divided field of view. The same imager component serves the role of multiple imagers would have played, making the system more universal and reducing component count.
2Measurement precision
If internal auto-exposure circuit is used to adjust imager exposure, then exposure accuracy is improved, but processing speed deteriorates due to time delay
Solution Approach 1:
The system pre-determines appropriate exposure settings based on detected conditions rather than waiting for the internal auto-exposure circuit to calculate and adjust after several frames. This preliminary action eliminates the time delay inherent in internal auto-exposure while maintaining adequate exposure accuracy.
Solution Approach 2:
The system uses feedback from the proximity sensor and illumination system to dynamically adjust exposure settings in real-time, bypassing the sluggish internal auto-exposure circuit. This external feedback mechanism enables faster response to changing lighting and distance conditions.
3Measurement precision
If illumination light is emitted at all times to ensure optimal reading performance, then reading accuracy is improved, but energy consumption and operator annoyance increase
Solution Approach 1:
The illumination light is emitted periodically only when needed, triggered by the proximity sensor detecting a product in the scanning zone. This periodic activation rather than continuous emission reduces energy consumption while maintaining reading accuracy when products are present.
Solution Approach 2:
The system automatically activates illumination based on product detection without requiring manual intervention. The proximity sensor triggers the illumination system to serve itself, providing optimal reading performance only when a product is being scanned rather than continuously.
Data Source
AI summary
An illumination time of an illumination system and/or an exposure setting of an imaging system are adjusted by a proximity system operative for detecting a product entering a field of view in a bi-optical, dual window, point-of-transaction workstation. The proximity system includes an infrared emitter for emitting infrared light to the product, and an infrared sensor for sensing return infrared light from the product. Multiple predefined thresholds are stored for the sensed return infrared light, and a predefined illumination time and/or exposure setting are stored and assigned to each predefined threshold. Adjustment of the illumination time and/or of the exposure setting is performed by comparing the sensed return infrared light from the product in real time operation with the stored predefined thresholds.