Optical Code Module Size Determination via Brightness Distribution
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Solution Overview
Problem
Conventional methods for determining the module size of optical codes, especially small module sizes, are inaccurate and prone to noise, requiring successful decoding before module size calculation, which hinders early decoding assistance and is susceptible to edge position localization errors.
Innovation Solution
A method that determines the module size from the brightness distribution of image data, using a greyscale histogram to estimate the module size without precise edge detection, focusing on the transition area and applying weighting factors for improved accuracy, allowing for early module size calculation even in sub-pixel ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional edge-based methods are used to determine module size, then the method is simple to implement, but the accuracy deteriorates for small module sizes due to discrete pixel levels and noise
Solution Approach 1:
The patent performs preliminary binarization of the image data before edge detection. By converting the greyscale image to a binary image first, the method reduces noise and discrete pixel level effects that degrade accuracy in small module size detection, while maintaining the simplicity of the overall approach
Solution Approach 2:
The patent introduces an intermediary step of calculating a threshold value from the image data's statistical properties (mean and standard deviation) and using this threshold to binarize the image before edge detection. This intermediary process acts as a mediator that filters noise while preserving edge information, resolving the contradiction between simplicity and accuracy
2Power
If edge position localization is performed on discrete pixel levels, then the processing is computationally simple, but the accuracy is limited and not sub-pixel accurate
Solution Approach 1:
The patent applies preliminary binarization to create a clear binary image before performing edge detection. This preliminary step establishes distinct transitions between light and dark regions, enabling more accurate edge localization that can achieve sub-pixel precision through interpolation methods while keeping computational complexity manageable
3Device complexity
If binarization is applied to reduce grey value information to one bit, then the edge detection becomes simpler, but information is lost that limits the accuracy of module size determination
Solution Approach 1:
The patent changes the parameter representation by introducing a threshold value calculated from statistical properties of the image data (mean and standard deviation). This threshold-based binarization preserves more information than fixed-threshold methods by adapting to the specific image characteristics, thereby maintaining higher accuracy while keeping the binarization process simple
Data Source
AI summary
A method for determining a module size of an optical code (20), wherein image data with the code (20) are detected, a brightness distribution is determined from the image data, and the module size is determined from the brightness distribution. The brightness distribution for example is a greyscale histogram.