Optical Code Reading Using Pattern Schemes for Error Correction
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Solution Overview
Problem
Conventional methods for reading barcodes are prone to errors due to the lack of robust error correction mechanisms, particularly in situations with multiple defects or impairments such as wavy surfaces or reflections, leading to increased misreads and non-reads.
Innovation Solution
A method that uses a scheme with both fixed and variable character portions to recognize and correct errors, where the scheme is derived from prior knowledge of expected code patterns, allowing for the identification of incorrectly read characters and the restoration of missing characters, thereby enhancing the reading rate and reducing misreads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional checksum correction is used for barcodes, then individual reading errors can be corrected, but multiple errors lead to misreads and the reading rate decreases
Solution Approach 1:
The patent applies preliminary action by using prior knowledge of expected code patterns (schemes) to pre-validate and pre-correct code characters before final decoding. The system compares read characters against predefined schemes that contain expected patterns, allowing early detection and correction of errors before they propagate through the decoding process, thereby maintaining high reading rates while improving reliability.
Solution Approach 2:
The patent implements feedback mechanisms by continuously comparing decoded code characters against predefined schemes and using the results to adjust and refine the decoding process. The system provides feedback on reading accuracy and uses this information to correct errors dynamically, enabling the system to maintain high reading rates even when multiple errors are present in the scanned codes.
2Reliability
If multiple code readers are provided to read codes from multiple sides, then reading coverage is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces an intermediary layer of prior knowledge schemes that mediate between the raw code reading process and the final decoding. This intermediary scheme-based validation system acts as a virtual additional reader that can verify and correct codes regardless of their orientation or quality, effectively providing the benefits of multiple readers without the physical complexity and cost of installing multiple actual code readers.
3Reliability
If error correction capacity is increased to handle multiple defects, then reading reliability improves, but the system becomes more complex
Solution Approach 1:
The patent applies preliminary action by establishing predefined schemes containing expected code patterns before the decoding process. These schemes serve as a preparatory framework that enables the system to quickly identify and correct multiple errors without requiring complex real-time error correction algorithms, thereby improving error correction capability while keeping the system relatively simple.
Solution Approach 2:
The patent utilizes parameter changes by comparing the actual read code characters against the expected parameters defined in the schemes. By changing the approach from traditional error correction algorithms to scheme-based parameter comparison, the system achieves enhanced error correction capability for multiple defects while avoiding the complexity of advanced mathematical correction methods.
Data Source
AI summary
A method is proposed of reading an optical code that encodes a message that has a character chain having a plurality of characters, said method comprising the steps: recording image data having the optical code; evaluating the image data with a reading of the optical code; comparing the read characters of the message with a scheme that contains a fixed character for at least one position of the message that is expected at this position in codes to be read; and recognizing an incorrectly read message and/or correcting the read message with reference to the comparison with the scheme. The scheme contains a variable character that is expected at this position in codes to be read for at least one position of the message, with a variable character being set to a partial range of the possible characters, but not to a fixed character.