Electro-Optical Reader Misdecode Reduction
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Solution Overview
Problem
Bar code readers often misdecode GS1 DataBar Limited symbols when they are embedded within Universal Product Code (UPC)-A symbols due to the lack of clear margins and incorrect scanning angles, leading to potential misreads.
Innovation Solution
A data capture assembly and programmed microprocessor in the reader system that captures light from the target symbol, generates an electrical signal, and processes it to determine whether the decoded signal is indicative of a Databar-limited or UPC-A symbol, using checks for finder patterns and contextual information to minimize misdecodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the reader decodes Databar-limited symbols without requiring clear margins, then the reading speed and capability are improved, but the accuracy deteriorates due to misdecodes from UPC-A symbols
Solution Approach 1:
The system performs preliminary decoding of Databar-limited symbols without requiring clear margins, capturing the decoded data before final validation. Then, it performs a verification step by checking for the presence of UPC-A guard bars or center guard patterns to determine if the decoded symbol is actually a fragment of a UPC-A symbol. This preliminary action allows high-speed reading while maintaining accuracy through subsequent verification.
Solution Approach 2:
The system implements feedback by comparing the decoded Databar-limited symbol against known UPC-A guard bar patterns and center guard patterns. If the decoded symbol contains patterns consistent with UPC-A guard bars or center guards, the system identifies this as a misdecode and rejects the Databar-limited interpretation. This feedback mechanism ensures accuracy while maintaining high reading speed.
2Adaptability or versatility
If the reader attempts Databar-limited decoding before UPC-A decoding, then the versatility is improved, but the reliability deteriorates due to increased misdecodes
Solution Approach 1:
The system performs preliminary decoding of Databar-limited symbols first, capturing the decoded data before final validation. Then, it performs a verification step by checking for the presence of UPC-A guard bars or center guard patterns to determine if the decoded symbol is actually a fragment of a UPC-A symbol. This preliminary action allows high-speed reading while maintaining accuracy through subsequent verification.
Solution Approach 2:
The system implements feedback by comparing the decoded Databar-limited symbol against known UPC-A guard bar patterns and center guard patterns. If the decoded symbol contains patterns consistent with UPC-A guard bars or center guards, the system identifies this as a misdecode and rejects the Databar-limited interpretation. This feedback mechanism ensures accuracy while maintaining high reading speed.
3Adaptability or versatility
If the scan line is made shorter to match compact Databar-limited symbols, then the adaptability is improved, but the reliability deteriorates due to tilted or incomplete scan lines
Solution Approach 1:
The system performs preliminary decoding of Databar-limited symbols without requiring clear margins, capturing the decoded data before final validation. Then, it performs a verification step by checking for the presence of UPC-A guard bars or center guard patterns to determine if the decoded symbol is actually a fragment of a UPC-A symbol. This preliminary action allows high-speed reading while maintaining accuracy through subsequent verification.
Solution Approach 2:
The system implements feedback by comparing the decoded Databar-limited symbol against known UPC-A guard bar patterns and center guard patterns. If the decoded symbol contains patterns consistent with UPC-A guard bars or center guards, the system identifies this as a misdecode and rejects the Databar-limited interpretation. This feedback mechanism ensures accuracy while maintaining high reading speed.
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 solution effectively reduces and prevents misdecodes by accurately distinguishing between Databar-limited and UPC-A symbols, ensuring reliable decoding and reducing the likelihood of symbol misinterpretation.
Implementation Method 1
a laser for emitting a laser beam
Implementation Method 2
a focusing lens assembly for focusing the laser beam to form a beam spot having a certain size at a focal plane
Implementation Method 3
a photodetector for detecting light reflected and/or scattered from the symbol and for converting the detected light into an analog electrical signal
Implementation Method 4
an imaging lens assembly for capturing return ambient and/or illumination light scattered and/or reflected from the symbol being imaged
Implementation Method 5
an illuminating light assembly for illuminating the field of view with illumination light from an illumination light source, e.g., a laser or one or more light emitting diodes (LEDs)
Data Source
AI summary
An arrangement for, and a method of, minimizing misdecodes of GS1 DataBar Limited (Databar-limited) symbols in a reader for electro-optically reading symbols of different symbologies, such as Universal Product Code (UPC) Version A (UPC-A) symbols, includes a data capture assembly for capturing light from a target symbol, and for generating an electrical signal indicative of the captured light; and a controller for processing and decoding the electrical signal, and for determining whether the decoded signal is indicative of a Databar-limited symbol, and for determining whether the decoded signal has characteristics indicative of a different symbology, such as the UPC-A symbol, to indicate whether a misdecode of the Databar-limited symbol has occurred.