Barcode Reader Ranging via Targeting Illumination
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Solution Overview
Problem
Barcode readers face challenges in accurately determining the distance of barcodes from the camera, which affects the selection of optimal operating parameters for effective reading, especially with varying illumination zones.
Innovation Solution
A barcode reader system that includes a targeting illumination system with distinct features, calibration data for feature offsets at different distances, and a processor to capture images and determine the estimated barcode distance, allowing for the selection of appropriate illumination sub-systems based on the calculated distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single illumination system is used, then the device complexity is reduced, but the reading accuracy varies across different zones
Solution Approach 1:
The illumination system is divided into multiple independent illumination subsystems, each optimized for a specific distance zone (near, mid, far). Each subsystem projects illumination at different angles and intensities suitable for its designated zone, allowing the system to maintain low complexity within each segment while achieving high overall accuracy across all zones.
Solution Approach 2:
Different illumination subsystems provide locally optimized illumination characteristics for different spatial zones. The near-zone subsystem uses specific illumination angles for close barcodes, the mid-zone subsystem provides intermediate illumination, and the far-zone subsystem uses different angles for distant barcodes. This local optimization ensures high reading accuracy in each zone without requiring a completely complex unified system.
2Measurement precision
If multiple illumination subsystems are used, then the barcode reading accuracy across different zones is improved, but the device complexity increases
Solution Approach 1:
The system dynamically selects and activates only the illumination subsystem appropriate for the current barcode distance. The processor determines which zone (near, mid, or far) the barcode falls into and activates only the corresponding illumination subsystem. This dynamic activation reduces the effective complexity during operation, as only one subsystem is active at a time despite multiple being available.
Solution Approach 2:
The targeting illumination system automatically determines the barcode distance and selects the appropriate illumination subsystem without external intervention. The system self-regulates by using the camera to detect the barcode position, calculating the distance, and autonomously activating the correct illumination subsystem, thereby managing the complexity internally without requiring complex external control.
3Device complexity
If the barcode distance is not accurately determined, then the operating parameter selection is simplified, but the barcode reading efficiency decreases
Solution Approach 1:
The system performs preliminary distance determination using the camera and targeting illumination system before activating the main illumination subsystem. By first capturing an image with the camera, calculating the barcode distance based on feature offsets, and then selecting the appropriate illumination subsystem, the system prepares the optimal parameters in advance. This preliminary action ensures efficient barcode reading without requiring complex real-time parameter adjustments during the actual reading process.
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
Enables accurate distance determination and optimal parameter selection for barcode reading across different zones, improving reading efficiency and accuracy.
Implementation Method 1
The targeting illumination may include a plurality of distinct illumination beams being projected so as to diverge from one another, the plurality of distinct illumination beams forming a plurality of distinct features on a target medium.
Implementation Method 2
A barcode is an optical machine-readable representation of information. Devices for identifying or extracting information from barcodes are generally referred to as barcode readers (or barcode scanners). An image-based barcode reader includes a camera for capturing an image of a barcode to be read. The camera includes a focusing lens that focuses light reflected from a target area onto a photo sensor array.
Implementation Method 3
The camera includes a focusing lens that focuses light reflected from a target area onto a photo sensor array.
Data Source
AI summary
A barcode reader comprising a targeting illumination system, a plurality of illumination systems, and a lens assembly may also comprise feature offset data. The feature offset data may be offsets between locations of a plurality of features projected by the targeting illumination system within a plurality of calibration image frames captured at different calibration distances. The barcode reader may (i) select two features projected by the targeting illumination system that are present in a barcode image captured via the first lens, (ii) determine a feature offset that indicates an offset between the two features, and (iii) estimate a barcode distance based on the feature offset and the feature offset data.