Optical Code Reading with Pre-Correction for Damaged Symbols
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Solution Overview
Problem
Conventional methods for reading optical codes, such as those using Reed-Solomon error correction, are limited in their ability to correct errors beyond a certain capacity, leading to reading failures due to defects or reflections, and existing brute force approaches are inefficient and prone to misreads.
Innovation Solution
A pre-correction method is introduced, where known code words are used to replace suspected erroneous code words, followed by a test process to determine if the code can be read correctly, potentially expanding the error correction capacity and reducing misreads by leveraging pre-knowledge of code word patterns from a history of read codes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Reed-Solomon error correction is used to correct reading errors, then reading reliability is improved, but the correction capacity is limited and cannot handle errors beyond a certain threshold
Solution Approach 1:
The patent applies preliminary action by performing a pre-correction step before the main Reed-Solomon decoding process. Known code words are identified and corrected in advance, reducing the number of errors that the Reed-Solomon algorithm needs to handle, thereby enabling successful decoding of codes with more errors than the standard correction capacity would allow.
Solution Approach 2:
The system uses self-service by leveraging the redundancy inherent in the code structure itself. Check code words and known code word positions are used to automatically identify and correct errors without external intervention, allowing the system to exceed standard correction limits by utilizing the code's own structural information.
2Reliability
If brute force permutation is used to correct binarization errors, then error correction capability is improved, but runtime increases significantly
Solution Approach 1:
The patent performs preliminary identification of known code words and their expected positions before attempting correction. This pre-processing step allows the system to target only specific suspected error locations rather than performing exhaustive brute force permutation across all possible code word combinations, significantly reducing computational runtime.
Solution Approach 2:
The correction process applies local quality by focusing computational resources only on specific locations where errors are suspected based on binarization threshold analysis. Rather than uniformly processing all code words, the system identifies critical modules with questionable polarity classification and applies correction only to those localized areas.
3Adaptability or versatility
If multiple code readers are deployed to read codes from multiple sides, then reading coverage is improved, but device complexity and cost increase
Solution Approach 1:
The patent enables a single code reader to achieve the functionality of multiple readers by using the code's own check code words and known code word structures to correct errors that would otherwise require multiple reading attempts from different angles. The system self-corrects reading errors by leveraging redundant information within the code itself.
Solution Approach 2:
The system performs preliminary error detection and correction using known code word positions and check code words before final decoding. This pre-correction process allows successful reading even when the code is partially obscured or damaged, reducing the need for multiple physical reading attempts.
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
This approach increases the reading rate by allowing codes to be read even when conventional error correction fails, with minimal runtime impact and reduced risk of misreads, by using pre-knowledge of code word patterns to correct errors and validate code recognition.
Implementation Method 1
an optoelectronic code reader having at least one light reception element for generating image data from received light
Data Source
AI summary
A method of reading an optical code (20) is provided that has a plurality of code words, wherein image data having the optical code (20) are recorded and evaluated to read out the code words, and wherein it is determined by a test process whether the code is read correctly. In this respect, a code word at at least one position of the code (20) is replaced with a code word known for this position in a pre-correction and the test process is carried out after the pre-correction.