雙偽裝影像運用直方圖修改與模數運算之可逆式資訊隱藏技術

Reversible Data Hiding on Dual Stego-Images Using Histogram Modification and Modulo Calculation

陳芮宇(Jui-Yu Chen)

指導教授 ： 李金鳳

朝陽科技大學/資訊學院/資訊管理系/碩士(2014年)

摘要

運用影像資訊隱藏將重要機密資訊直接藏入影像中而不會造成影像品質有太大改變，故藏有訊息的偽裝影像在網路的傳遞過程中並不易引人注目，進而有效的達到保護資料的目的。現今有越來越多學者在可逆式多重偽裝影像藏匿技術的領域進行探究。所謂的多重偽裝影像藏匿法，主要是將機密資訊平均藏在多張偽裝影像上，其目的旨在增加資訊負載量並保有一定的影像品質，又能兼顧機密資訊藏在偽裝影像上的安全性。近年在各種多重偽裝影像藏匿技術的發展中，Chang學者等人利用魔術矩陣將機密訊息藏在像素上，使影像品質維持在45dB而機密資訊的負載量為1 bit per pixel (bpp)；Lee學者利用十字架位置或九宮格位置的指引方式隱藏機密訊息有效達到高影像品質，但其方法卻需收受雙方事前預設多而複雜的規則，在應用方面將造成不便。本論文提出一個雙重可逆式偽裝影像資訊隱藏技術。本研究的資訊隱藏技術是一個兩階段的方法，第一階段為計算區塊中的差值，透過直方圖統計後，將機密資訊藏在尖峰點上，再於第二階段利用四象限魔術矩陣模數運算的差值來產生兩張偽裝影像，不僅使偽裝影像擁有很高的藏量，其平均藏量 1.21 bits per pixel，且可維持一定的影像品質，其平均為 44 dB 。此外，本論文亦針對目前已發表過有關於雙重可逆式偽裝影像資訊隱藏技術的學術論文，從資訊的負載量、視覺影像品質與各學者的研究結果進行比較，並探討未來相關領域可以延伸的部分。

關鍵字

直方圖位移法 ； 可逆式資訊隱藏技術 ； 隱藏學 ； 資訊隱藏 ； 多重偽裝影像藏匿法

並列摘要

Data hiding in images camouflages the confidential information into the image straight such that the images-quality can’t be changed so much. The confidential information can’t be discovered in sending process on the Internet, and the purpose of data protection is achieved really. Reversible data hiding technology not only provides a safe communication channel for confidential information but also achieves lossless carrier on image recovery. More and more scholars dedicated to the field about reversible data hiding technology on multiple steganographic images nowadays. The aim is the increase of payload, images-quality, and security of confidentiality information hidden in the stego-images in same time. Among the development of reversible data hiding technology on multiple steganographic images in recent years, the methods of Chang et al. and Lee et al. are well known. All of them used image pixels as carriers to provide a safe communication channel for confidential information. The image-quality is maintained to 45dB and the payload of confidential information is 1 bit per pixel (bpp) for Chang et al. method; Lee et al. designed the guidelines methods of crucifix positions or squared positions to hide confidential information and maintained high images-quality, but the sender and receiver need to communicate complicated rules, thus theses methods are inconvenient in the application. This thesis presents a two-staged method of reversible data hiding on dual steganographic images. The first stage calculates the pixel difference among the blocks and generates a histogram from the differences such that the confidential information can be embedded into the peak points from the histogram. The second stage generates two stego-images using the differences in blocks from modulo calculation on a four-quadrant magic matrix. This thesis investigates the results of publication academic papers about the reversible data hiding methods on dual steganographic images and compares the performance in terms payload and visual images-quality with those methods. There is higher payload in stego-images with 1.21 bits per pixel on average, maintaining good images-quality of 44 dB measured by PSNR values. In addition, it presents the guide about exploring part of related fields in the future.

並列關鍵字

Histogram shifting mehtod ； Reversible data hiding ； Steganography ； Data hiding ； Multiple steganographic images

參考文獻

[18]J. Wen, J. Lei and Y. Wan, “Reversible Data Hiding Through Adaptive Prediction and Prediction Error Histogram Modification,” International Journal of Fuzzy Systems, Vol. 14, No. 2, pp. 244-256, 2012.

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