混合網點數位浮水印輸出控制研究

A Study on Output Control of Watermarking with Blended Halftone Dots

吳鴻明(Hong-Ming Wu)

指導教授 ： 王希俊

國立臺灣師範大學/科技學院/圖文傳播學系/碩士(2006年)

摘要

混合網點數位浮水印技術，應用調幅網點及調頻網點兩種不同形式的網點，將浮水印藏入半色調影像中，藉由不同形式的網點對複印或是掃描等數位複製設備的取樣差異來進行解碼。實體影像受限於輸出設備因素，只能以半色調的形式來呈現，半色調影像經由人類視覺的模糊化積分後，產生連續調影像的感覺。數位浮水印是在數位影像中藏入標記、圖案、號碼等等資訊，本研究針對混合網點數位浮水印輸出成實體浮水印，考量輸出設備特性，控制網點的大小及疏密程度，使數位浮水印輸出後，得到最佳的隱蔽性，且經由複印機等解碼設備偵測後，可以得到隱藏的資訊。

關鍵字

數位半色調技術 ； 混合網點 ； 數位浮水印 ； 網點擴張

並列摘要

The objective of this thesis is to hide watermark with hybrid halftone dots in a printed halftone image. Two different halftone dots, Amplitude Modulation (AM) and Frequency Modulation (FM), are use to design the digital watermark. The output parameters should be carefully controlled to obtain printed image with hidden digital watermark. As the printed image is copied or scanned, the hidden watermark is shown because of the under-sampling of the FM halftone dots. The outcome of this research has many potential applications in security printing, such as ID, legal document, checks, stamps, and currency.

並列關鍵字

Digital halftoning ； Hybrid halftone dots ； Digital watermarking ； Dot gain

參考文獻

[1] W. Bender et al., “Techniques for data hiding”, IBM System Journal, vol 35, Nos3&4, pp 313-336, 1996.

[2] C.C. Kuo, T. Kalker, W. Zhou, ”Digital Rights Management - from the guest editors”, IEEE Signal Processing Magazine, vol. 21, Issue 2, pp11-14, March 2004.

[3] J. Abigail and R. H. R. Harper., “The Myth of the Paperless Office” , MIT Press,Cambridge, MA, 2001.

[5] D. Gruhl and W. Bender, “Information Hiding to Foil the Casual Counterfeiter”, proceedings, 2nd International Workshop on information hiding, Lecture Notes in Computer Science, 1525, pp 1-15, Portland, Oregon, April 1998.

[6] D.L. Hecht, “Embedded data Glyph technology for hardcopy digital documents”, SPIE 2171, pp. 341-352, 1995.