Electro-Optical Reader Polarity Validation for GS1 DataBar Symbols
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Solution Overview
Problem
GS1 DataBar-14 and DataBar Expanded symbols lack outer margins, leading to misreads when printed in normal or inverse codes, as readers cannot determine polarity, resulting in incorrect decoding and prompting manufacturers to disable inverse code decoding, which is unsatisfactory for customer expectations.
Innovation Solution
An electro-optical reader arrangement and method that captures light from the symbols, simultaneously processes and decodes signals as both normal and inverse polarities, using a controller to validate results with checksum functions, ensuring accurate decoding by generating outputs based on validity determinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the reader decodes symbols as inverse codes to meet customer expectations, then the adaptability is improved, but misreads occur due to inability to determine polarity
Solution Approach 1:
The system performs preliminary validation by checking checksums for both normal and inverse polarity interpretations before final decoding. This advance verification prevents misreads by identifying valid interpretations beforehand, allowing the system to correctly handle inverse codes while maintaining decoding accuracy.
Solution Approach 2:
The system uses checksum validation as a feedback mechanism to verify decoding results. By checking whether the decoded data produces a valid checksum under both normal and inverse polarity assumptions, the system receives feedback that guides it to select the correct interpretation, thereby preventing misreads while maintaining versatility.
2Reliability
If the reader processes signals as both normal and inverse polarities simultaneously, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The processing task is segmented into distinct validation steps: first checking normal polarity with checksum, then checking inverse polarity with checksum if needed. This segmentation of the validation process into discrete, manageable steps reduces overall processing complexity while maintaining high reliability through thorough verification.
Solution Approach 2:
The system performs partial processing by only fully decoding the inverse polarity interpretation when the normal polarity checksum validation fails. This selective approach avoids the excessive complexity of always processing both polarities completely, while still ensuring reliability by performing inverse decoding when necessary.
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
Prevents misreads by ensuring accurate decoding of GS1 DataBar symbols regardless of polarity, meeting customer expectations while maintaining reliable reading capabilities.
Implementation Method 1
a photodetector for detecting return light reflected and/or scattered from the symbol and for converting the detected return light into an analog electrical signal
Data Source
AI summary
An arrangement for, and a method of, preventing a misread of a one-dimensional symbol that can be read in either one of two polarities in an electro-optical reader. A data capture assembly captures light from the symbol, and generates an electrical signal indicative of the captured light. A controller simultaneously processes and decodes the electrical signal as a first decoded result of one of the polarities and as a second decoded result of the other of the polarities. The controller also determines the validity of the first and second decoded results, and generates an output in dependence upon the validity determination.