運用賽局理論古諾模型機制於半易碎型浮水印

Semi-Fragile Watermarking with Applying Game-Theoretic Cournot Model

黃齡萱(Ling-Hsuan Huang)

指導教授 ： 張隆紋

國立清華大學/電機資訊學院/資訊系統與應用研究所/碩士(2010年)

https://doi.org/10.6843/NTHU.2010.00482

摘要

在現代網路的快速發展下，影像內容在傳送時更容易遭到複製或竄改，因此傳輸內容的安全性是一個重要的議題。本篇論文選擇半易碎型浮水印技術。半易碎型浮水印具有抵抗一定程度的影像壓縮處理破壞以及偵測影像遭受破壞的特性，因此可用來驗證影像及偵測惡意竄改。我們在設計的浮水印系統選擇不需原始影像的機制，我們提出取餘數的機制來藏入浮水印。
我們希望藏入浮水印後，即使是受到正常的影像處理，能仍維持較高的影像品質並且能正確的偵測出改變的訊號，對於影像品質的控制我們選擇經濟學中常用的賽局理論來分析。在賽局理論中，我們將半易碎型浮水印中的兩個特性：驗證和竄改偵測，視為兩個在賽局中競爭的參賽者，將要控制的品質視為兩位參賽者要競爭的資源，經由賽局中的數學模型─ 古諾模型的分析來找到最佳解，達到最佳的影像品質的控制。
我們比較提出的方法和一般資源分配的方法，發現我們的方法即使在百分之七十的JPEG壓縮下仍然可以運作。最後，實驗結果可以運用於設計一個有效率的離散餘弦轉換(DCT)的浮水印系統，即使在JPEG壓縮下仍可偵測出改變訊號。

關鍵字

半易碎型浮水印 ； 賽局理論

並列摘要

In the rapidly development of the internet, the image content will be more easily be copied or tampered while delivering trough the net. The paper chooses the Semi-fragile watermarking technique. Semi-fragile watermarking can resist legal manipulations such as JPEG compression, and detect the tampered image. Therefore, it can be used to authenticate the image and detect if the image is tampered. For the blind scheme, we propose the Modulate mechanism to embed the watermark pattern.
After embedding the watermark into the image, we hope to maintain the high quality and correctly detect the changed signal of the image even if it under the normal image processing. To match this goal, we choose Game Theory to analyze it. In Game Theory, two features of the Semi-fragile watermarking, Authentication and Tamper Detection are considered as two players who compete in the game. And the quality of the image is considered as the resource that two players have to compete. By the analysis of the Cournot model, it can find the best solution to control the image quality.
We compare the proposed method and the average resource allocation method to find that our method can work even in JPEG compression 70%. Finally, the results are applied to design an efficient Discrete Cosine Transform (DCT) semi-fragile watermarking system which allows detecting local forgery signals in spite of JPEG compression.

並列關鍵字

Semi-fragile watermarking ； Game theory ； JPEG compression

參考文獻

[1] H.l. Zhang and M.M. Gao “A semi-fragile digital watermarking algorithm for 2D

[2] S.B. Che et al. “SEMI-FRAGILE IMAGE WATERMARKING ALGORITHM BASED ON

[3] L. Bo et al. “A New Semi-fragile Watermarking Algorithm for Image

[4] X. Zhao et al. “A Novel Semi-Fragile Image Watermarking Authentication and

Self-restoration Technique Using the Slant Transform”, , IEEE, vol. 1, pp. 283-286,