Watermark Image Correction for Folded Bill Authentication
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Solution Overview
Problem
The identification accuracy of paper sheets, such as bills, is compromised when the folding line coincides with the watermarked area, as existing methods fail to adequately remove wrinkles, leading to reduced authenticity verification.
Innovation Solution
A paper sheet identification apparatus that includes a reading mechanism for watermarked images, a converter to process pixel data, a correction module to adjust density values, and a comparison system with a reference image to enhance authenticity verification, even when folding lines are present.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a watermarked area is used for authenticity identification, then identification accuracy is improved, but when a folding line coincides with the watermarked area, the identification accuracy is lowered
Solution Approach 1:
The patent applies preliminary action by performing image correction processing before authenticity identification. The system reads the watermarked image, corrects density values to remove folding line effects, and then performs authentication. This preliminary correction ensures that the watermark can be accurately read even when folding lines are present, resolving the contradiction between using watermarks for high-accuracy identification and the harmful effect of folding lines.
Solution Approach 2:
The patent applies parameter changes by modifying the density values of pixels in the watermarked image. The correction processing part calculates average density values and adjusts individual pixel densities to match, thereby removing the visual effects of folding lines and creases. This parameter adjustment allows the watermark to be clearly identified despite physical deformations in the paper sheet.
2Measurement precision
If a presser part is used to press the bill to smooth wrinkles, then identification accuracy is improved, but folding lines and creases may not be sufficiently removed
Solution Approach 1:
The patent replaces the mechanical presser part system with an image processing system. Instead of physically pressing the bill to remove wrinkles, the system reads the watermarked image and applies digital correction to remove the visual effects of folding lines. This substitution maintains identification accuracy without relying on mechanical intervention that may be insufficient for deep creases.
Solution Approach 2:
The patent introduces an image correction processing part as an intermediary between the image reading and authenticity identification. This intermediary component analyzes the watermarked image, detects folding line effects through density value analysis, and corrects them before authentication. This intermediary processing step effectively removes wrinkle effects without requiring physical contact with the paper sheet.
3Device complexity
If the watermarked image is directly compared with the reference image, then the process is simple, but folding lines cause misidentification
Solution Approach 1:
The patent applies preliminary action by inserting an image correction step before the authenticity comparison. The correction processing part adjusts density values in the read watermarked image to eliminate folding line effects, ensuring that the subsequent comparison with the reference image is accurate. This preliminary processing maintains relative simplicity while dramatically improving identification accuracy.
Solution Approach 2:
The patent extracts and corrects the harmful folding line effects from the watermarked image before authentication. By separating the correction process from the authentication process, the system removes the interference of folding lines while maintaining the simplicity of the overall workflow. The correction extracts only the necessary density adjustments, leaving the rest of the authentication process unchanged.
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
The apparatus effectively improves authenticity identification accuracy by correcting density values and comparing pixel data, ensuring accurate verification of paper sheets despite folding lines or creases.
Implementation Method 1
The bill moving inside the bill traveling route is irradiated with light, and a transmitted light or a reflected light therefrom is received by a light receiving sensor
Data Source
AI summary
A bill identification apparatus accurately identifying an authenticity with a folding line formed in a watermark. The bill identification apparatus includes: bill reading means; a converter which converts the watermarked image read by the bill reading means for each pixel containing color information having brightness; a image correction processing part which calculates an average density value for each pixel array in one direction, an average density value for each pixel array in the other direction, and an average density value of an entire watermarked image and corrects density values of respective pixels so as to approximate or match the average density value of the entire watermarked image; a reference data storage part which stores a reference watermarked image; an identification processing part which compares the corrected image by the image correction processing part with the reference watermarked image and identifies an authenticity.