Optical Code Defect Detection for More Reliable Reading
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Solution Overview
Problem
Existing code reading technologies struggle to accurately read optical codes with defects such as damage, poor printing, contamination, or optical impairments, often leading to reading errors that conventional error correction methods like Reed-Solomon cannot handle when defects exceed their capacity.
Innovation Solution
A method that uses edge and binarization criteria to detect defects in optical codes, allowing for more effective utilization of error correction by identifying and marking affected codewords, thereby doubling the number of correctable errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional Reed-Solomon correction is used to correct reading errors, then reading reliability is improved for codes with minor defects, but reading fails when defects exceed the error correction capacity
Solution Approach 1:
The patent applies preliminary defect detection and marking before error correction. By identifying and marking defective code modules in advance using edge and binarization criteria, the system prepares the error correction algorithm with prior knowledge of error locations, enabling it to correct twice as many errors as conventional methods
2Adaptability or versatility
If multiple code readers are installed to capture objects from multiple orientations, then reading coverage is improved, but system complexity and cost increase
Solution Approach 1:
The patent changes the processing parameters of the code reading system by introducing defect detection parameters (edge criterion, binarization criterion) and error marking parameters. This allows a single code reader to achieve the functionality of multiple readers by improving the software-based error handling capability
3Measurement precision
If manual rescanning or re-sorting is performed to correct reading errors, then reading accuracy is improved, but productivity and efficiency decrease
Solution Approach 1:
The patent implements self-service error correction by automatically detecting defects, marking erroneous code modules, and correcting errors through the enhanced error correction algorithm. This eliminates the need for manual rescanning or re-sorting operations
Data Source
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AI summary
A method for reading an optical code (20) is specified, comprising the steps of recording image data with the optical code (20), determining defects (30), and evaluating the image data by reading the code words. The defects (30) are determined using an edge criterion and/or a binarization criterion, wherein the edge criterion evaluates whether a code module lies in an edge-free region of the image data that is larger than a predetermined multiple of the module size, and wherein the binarization criterion evaluates whether a code module with gray values close to a binarization threshold has been recorded.