基於俄羅斯方塊以及立體視覺影像的資訊隱藏方法之研究

Abstract

隨著網路的普及與頻寬的增加，在網路上流通的媒體種類也變得更加豐富多樣。雖然在多媒體傳輸上越來越便利，但資訊安全及多媒體認證的問題也隨之而來。本論文使用了兩種不同的媒體提出了全新的資訊隱藏方法，分別作為隱寫及浮水印之用。 本論文的隱寫方法利用俄羅斯方塊作為載體，機密訊息嵌入在遊戲中產生的方塊序列中。俄羅斯方塊在每次進行遊戲時，就會產生一個新的方塊序列。所提的方法也具有相同的特性。除此之外，本論文更進一步地提出使用此方法的情境，以及一個模擬程式。透過理論證明及實驗結果，顯示所提的方法具有無法被偵測性，是一個安全的隱寫方法。 本論文的浮水印方法是應用在立體影像，立體影像是由左眼影像與右眼影像所構成，由於左、右眼影像具有非常高的相似性，透過特徵圖便可得到一個具有強韌性的浮水印。透過AC係數交換，浮水印將被嵌入在左眼影像中。在浮水印驗證時，嵌入浮水印後的立體影像將被用來重新計算特徵圖，接著將嵌入左眼影像的浮水印萃取出來，並轉換成預測特徵圖。若預測特徵圖與重新計算的特徵圖相似，便可證明影像的所有權為嵌入浮水印者所有。實驗結果顯示，比起現有的方法，所提的方法不僅在面對多種惡意攻擊時有更好的強韌性，對嵌入影像的破壞也比較小。

With the development of Internet and the bandwidth speed, the media type of communication becomes more complex than before. The increased convenience of multimedia transition makes computer security and media authentication become critical problems. In this study, two novel data hiding methods on two kinds of multimedia are proposed. One is for steganography, and the other is for watermarking. The proposed steganographic method is based on online Tetris games, in which secret messages are embedded using a generated tetrimino sequence. The study also presents a scenario and a simulator for the proposed method. Theoretical proof and experimental results are provided to demonstrate that the proposed method is undetectable. The proposed watermarking method is for stereo-pair images. Based on the fact of that the left and right images of a stereo pair are very similar, a robust watermark is created and embedded in the left image by swapping the AC coefficients. Experimental results indicate that the proposed method exhibits greater robustness against malicious attacks and produces less distortion than existing methods do.