QR Code之資訊隱藏—應用不同網點面積之混合網點

Abstract

QR Code (Quick Response Code)是一種由黑色和白色模組所組成的矩陣式二維條碼。隨著二維碼技術的廣泛應用，QR Code 常被用於產品推廣、產品追蹤及溯源、產品真僞鑒別、入場票券等的儲存媒介。然而，現有印刷品上的QR Code，不僅占據印刷品上一定的空間，還容易被盜印。因此本研究將調幅網點 (Amplitude Modulation，AM) 與調頻網點 (Frequency Modulation，FM) 導入QR Code，使AM網點與FM網點在QR Code上的網點面積百分比均衡，產生不同網點面積百分比的混合網點QR Code，此QR Code在印刷品上，人的眼睛是察覺不出來，但手機可掃碼識別，達到資訊隱藏的目的。本研究採用實驗研究法，其中QR Code中的黑色模組用AM網點來表示，白色模組用FM網點來表示。通過調整次模組内AM網點的形狀來改變網點面積百分比，以此表示QR Code中的黑色次模組，FM網點則將次模組中間挖空，形成白點來表示QR Code中的白色次模組，且次模組内FM網點面積百分比通過調配後和AM網點均衡，以此產生不同網點面積百分比的混合網點 QR Code，來測試QR Code 輸出後資訊隱藏的成效。此外還嘗試將QR Code的定位標記點（Finder Patterns）和無定位標記點的混合網點QR Code另外輸出來測試資訊隱藏成效。研究結果顯示，所設計的混合網點QR Code達到資訊隱藏之創新成效，並確定了可被掃碼識別的最低網點面積百分比。針對3x3無定位標記點的混合網點QR Code，輸出後曡加在寫有文字的紙張上進行的抗干擾性分析。分析表明有部分QR Code的干擾程度超出QR Code的容錯範圍，因此在程式中對九個QR Code進行投票分析，經投票分析後，碼字錯誤大大降低，QR Code還是能被掃碼識別，藉由QR Code定位標記點的隱藏，能將QR Code與文件做更好的整合。QR Code (Quick Response Code) is a matrix-type two-dimensional barcode composed of black and white modules. With the widespread application of two-dimensional barcode technology, QR Code is often used as a storage medium for product promotion, product tracking and traceability, product authentication, and event ticketing. However, the existing QR Codes on printed materials not only occupy a certain amount of space but are also prone to counterfeiting. Therefore, this study introduces Amplitude Modulation (AM) and Frequency Modulation (FM) halftoning into QR Codes, balancing the dot area percentage of AM and FM dots on the QR Code to create a hybrid AM/FM-dot QR Code with different dot area percentages. This QR Code is imperceptible to the human eye when printed on materials but can be scanned and recognized by mobile phones, achieving the purpose of information hiding.This study adopts an experimental research method, where the black modules in the QR Code are represented by AM dots and the white modules by FM dots. Specifically, the dot area percentage is altered by adjusting the shape of the AM dots within the sub-modules to represent the black sub-modules in the QR Code, while the FM dots create white points by hollowing out the center of the sub-modules to represent the white sub-modules. The dot area percentages of FM dots within the sub-modules are balanced with AM dots after adjustment to generate a mixed-dot QR Code with different dot area percentages to test the effectiveness of information hiding in the QR Code output. Additionally, the study attempts to test the information hiding effectiveness by outputting mixed-dot QR Codes without finder patterns.The research results indicate that the designed hybrid AM/FM-dot QR Code achieves innovative information hiding effectiveness and determines the minimum dot area percentage that can be recognized by scanning. For the 3x3 hybrid AM/FM-dot QR Code withoutfinder patterns, interference resistance analysis was conducted by overlaying it on text-printed paper. The analysis shows that the interference level of some QR Codes exceeds the error correction range of the QR Code. Therefore, a voting analysis was performed on nine QR Codes within the program. After the voting analysis, the codeword errors were significantly reduced, and the QR Codes could still be scanned and recognized. By hiding the finder patterns of the QR Code, better integration of the QR Code with the document can be achieved.