基於VQ與SOC的資訊隱藏法

A DATA HIDING SCHEME BASED ON VQ AND SOC

谷威涵(ku wei han)

指導教授 ： 黃秀園 ； 李正吉

亞洲大學/資訊學院/電腦與通訊學系碩士班/碩士(2007年)

摘要

近年來，由於電腦與網路的通訊技術快速的發展，人們也注意到該如果保護通訊責料的安全。因此，資訊責藏的技術開始被提出與研究。隨著責訊資藏技術的發展，責訊責藏主要被分為二大領域：數位浮水印和隱藏學。數位浮水印是用來保護數位影像的著作權或是顯示擁有人。數位浮水印著重的是將浮水印藏入數位影像復，即使這些數位影像經過了一些常用的數位影像處理，還是能找出數位影像中的浮水影。隱藏學跟數位浮水印不同的是，隱藏學的目標在於將密秘責訊藏入影像中，讓欄截者發現不出異常，以達到密秘通訊的目的。隱藏學的主要議題是如何隱藏入更多的責訊以及如何保持藏入責訊復的偽圖的影像品質。隱藏學根據資訊隱藏方法的不同，主要分為空問域的資訊隱藏法和頻率域的資訊隱藏法。
在本篇論文中，我們提出了一個新的灰階影像的隱藏法基於Vector Quantization compression ( VQ ）和Search 一Order codin 劇SOq 。我們的方法利用4 個編碼簿以及VQ 與SOc 的編碼排列組合，可以在一對VQ 區塊中藏入6 位元的資訊，隱藏的資訊量是Yu 等人方法的兩倍，而且偽圖的影像品質也可以保持跟Yu 等人方法的影像品質一樣。

關鍵字

資訊隱藏

並列摘要

In recent years, the computer and network communication techniques have been developed quickly, people attach great importance to secret communication. For this reason, information hiding was being proposed. As the information hiding techniques go far, it is mainly classified into two categories: copyright marking and steganography. Copyright marking is used to embed the copyright information, like a signature or a trademark, into the cover image for ensuring the copyright. The emphasis on copyright marking is that the watermark hidden in the cover image must be able to be retrieved, even if the stego-image has been applied lots manipulations such as cropping, lossy compression, resize, etc. Watermark is usually very small, and composes of visible watermarking and imperceptible watermarking.
Steganography is different from watermarking. The goal of steganography is how to embed secret data into the cover image, let the interceptors neither feel something peculiar nor want to attack the stego-image. In the other word, steganography is to provide a secret communication. The key issues in steganography are how to embed more secret data and to remain the stegoimage’s good quality. The technique of data hiding in images can be classified into two categories, i.e., data hiding in spatial domain schemes and data hiding in frequency domain schemes.
Neither data hiding in spatial domain schemes nor data hiding in frequency domain schemes can be used in other domain. In this thesis, we propose a new steganographic scheme based on Vector Quantization compression (VQ) and Search-Order Coding (SOC) for gray-level images. The embedded capacity of this scheme is higher than the others in which are based on VQ and the quality of stego-image is acceptive. In general, the capacity of the schemes based on VQ are usually 1-bit per block. In 2004, Yu et al proposed a scheme to increase the capacity to 3-bit per pair of blocks. In our scheme, we used multiple codebooks and chose the combinations of per pair of blocks, to embed the secret data. The capacity was increased to 6-bit per pair of blocks, and the quality is the same as Yu et al.’s scheme.

並列關鍵字

Steganography, Information hiding, Date hiding, Cover image, Stego-image, Least-Significant-Bits substitution (LSB), Vector Quantization compression (VQ), Search-Order Coding (SOC).

參考文獻

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