可改變複製文件顯示意義之紙張載體數位浮水印設計
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Date
2012-07-31
Authors
王希俊
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Abstract
本研究利用光學式的數位浮水印隱藏技術，設計客製化資訊隱藏圖案於紙張載體，以人眼正常觀看下，只可見外顯之圖文，無法察覺其中所隱藏浮水印圖案，但複印或掃描後，因取樣頻率的差異，浮水印因而顯現，並改變了原圖文之意義，以增強紙張載體之客製化及防偽功能。本研究使用數位半色調演算法原理，由調幅(AM)及調頻(FM)網點合成編碼加密，經濃度匹配導表校正後，將設計完成的客製化圖案輸出於紙張載體，可透過複印機或光學掃描器偵測，除達到版權宣示效果外，原圖文意義可被改變，其中包括影像黑白反轉及內容改變。本研究成果，將增進傳統紙張的防偽功能及增添趣味，以客製化圖案用於紙張載體上，並能提高其附加應用價值。
The objective of this research is to develop an optical anti-counterfeiting method by watermark with hybrid halftone dots of amplitude modulation (AM) and frequency modulation (FM) which can alter the meaning of the document contest after duplication. A density calibration chart is constructed first to obtain the proper parameters to synthesize the watermark. This research gives the digital watermark in printed medium another alternative to declare copyright. The results show that watermark will appear by duplicating or scanning the original document, and the content of the document is altered. It will have many potential value-added applications such as secured document, personalized stationery products and etc.
The objective of this research is to develop an optical anti-counterfeiting method by watermark with hybrid halftone dots of amplitude modulation (AM) and frequency modulation (FM) which can alter the meaning of the document contest after duplication. A density calibration chart is constructed first to obtain the proper parameters to synthesize the watermark. This research gives the digital watermark in printed medium another alternative to declare copyright. The results show that watermark will appear by duplicating or scanning the original document, and the content of the document is altered. It will have many potential value-added applications such as secured document, personalized stationery products and etc.