植基於整數小波轉換之可逆式影像資料隱藏技術

A Study on Reversible Image Data Hiding Technique Using Integer Wavelet Transformation

曾平佳(Ping-Chia Tseng)

指導教授 ： 謝仕杰

國立虎尾科技大學/電機資訊學院/資訊工程研究所/碩士(2014年)

https://doi.org/10.6827/NFU.2014.00006

摘要

影像資料隱藏技術主要為了防止機密資料在傳輸過程中遭受竊取或是竄改的技術。此技術主要是透過嵌入演算法把機密資料藏於數位影像中，然後產生帶有機密資料的偽裝影像。嵌入機密資料的影像不能與原始影像差異太多，才不會被有心人士發現。透過提取演算法可將機密資訊從帶有機密資料的數位影像中提取。當還原後的影像與原始影像完全相同時稱為可逆式資訊隱藏技術。
本論文提出了一種在小波轉換下的可逆式資料隱藏技術。所提出的方法使用將機密資訊藏入至影像之整數小波轉換係數之策略來實作資料隱藏技術。此技術主要是先透過整數小波轉換把空間域的像素值轉換為頻率域中的頻率係數。轉換後會形成四個不同頻率的頻帶，分別為低頻(LL)、中頻(HL、LH)和高頻(HH)，每個頻帶都帶有不同的影像特性。然後針對四個不同頻率的頻帶之係數來當做資料隱藏之載體。使用整數小波轉換主要是為了反小波轉換時不會造成影像失真，來達到可逆的效果。資料隱藏部分首先根據每個頻帶的特性設計適用於此特性的預測式資料隱藏方法，之後再搭配直方圖位移的技術做機密資料嵌入跟提取的動作。根據實驗結果的分析，本論文提出的資料隱藏方法跟其它類似的演算法比較時有較好的影像品質跟資料隱藏量。

關鍵字

可逆式資料隱藏 ； 整數小波轉換 ； 空間域 ； 頻率域 ； 直方圖位移

並列摘要

Image data hiding technology is a technology which to prevents confidential information from being stolen or altered during transmittance. The technology mainly hides confidential information in digital image through embedding algorithm, to produce stego-image that is confidential. In order not to be suspected, the embedded confidential information image should not have too much difference from the original one. Confidential information can be extracted from the digital image through extraction algorithm. It is called reversible data hiding technology wherein the restored image is completely the same as the original one.
This paper proposes a reversible data hiding technology by wavelet transformation. The methods hide confidential information into integer wavelet transformation coefficient of the image to apply the information hiding technology. The technology mainly utilizes integer wavelet transformation to change the pixel value in the spatial domain into the frequency coefficient in the frequency domain. Four frequency bands will form after the transformation, respectively LL, HL, LH and HH, which have different image features. Frequency band coefficients of four different frequencies are regarded as carriers for hiding information. In order not to cause image distortion in reverse wavelet transformation, it uses integer wavelet transformation to realize the desired reversible outcome. In data hiding aspect, it first designs a predictable data hiding method according to the characteristics of each frequency band, then combines histogram displacement technology to conduct the embedding and extraction of confidential information. According to the analysis of experimental results, the data hiding method proposed in this paper has better image quality and information hiding quantity when compared with similar algorithms.

並列關鍵字

reversible data hiding ； integer wavelet transform ； spatial domain ； frequency domain ； histogram shifting

參考文獻

[17]D. S. Kim, G. J. Lee and K. Y. Yoo, "Reversible Image Hiding Scheme for High Quality Based on Histogram Shifting," IEEE Tenth International Conference on Information Technology： New Generations, pp.392-397, 2013.

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