基於CSD資料表示與整數轉換之可回復式資料隱藏

REVERSIBLE DATA HIDING BASED ON CSD DATA REPRESENTATION AND AN INTEGER TRANSFORM

林偉聖(Wei-Sheng Lin)

指導教授 ： 汪順祥

大同大學/電機資訊學院/通訊工程研究所/碩士(2008年)

摘要

在本篇論文，我們提出了兩個可回復式資料隱藏的方法。第一個可回復式資料隱藏的方法，是將原始影像切割成不同大小的非重疊影像區塊，並且將所要嵌入的資料，由原本的二位元表示方式改變成CSD的表示方式。其中，將影像切割成不同大小的區塊，是為了增加其藏入資料量的容量。而利用CSD的表式方式，則是由於它具有最小的非零的個數，所以能夠減少像數值的改變。在第二個可回復式資料隱藏的方法中，是基於一種整數轉換和直方圖的位移。其逆轉換主要是利用相鄰的像素值來還原原始的像素值。我們可由轉換過後整張影像差值的直方圖，將所要嵌入的資料藏入影像中，並且修改些微的像素值來達到資料影藏的目的。我們所提出的這兩個方法，在將隱藏資料取出後，皆能夠恢復其原始影像。由實驗結果可看出，我們所提出的這兩個方法皆具有較大的隱藏容量(在相同的PSNR之下)或是高的PSNR(在相同的隱藏容量)。

關鍵字

整數轉換 ； CSD資料表示 ； 可回復式資料隱藏 ； 直方圖

並列摘要

This thesis presents two reversible data hiding methods. The first reversible data hiding method divides an input image into non-overlapping blocks and embeds data using CSD data representation. We divide the original image into smaller blocks, in order to increase the data capacity. The CSD data representation has a minimum number of nonzero digits thus it can decrease alteration of the pixels. The second reversible data hiding method embeds data based on an integer transform and histogram shifting. The invertible transform exploit the correlations among adjacent pixels in an image region. We calculate the mean and difference values of the adjacent pixels. Based on the histogram of the difference values, we modify pixel values slightly to embed data into the image. These two methods can recover the original image without any distortion from the marked image after the hidden data have been extracted. Experimental results show that these two methods outperform the prior works in terms of a larger payload (at the same PSNR) or a higher PSNR (at the same payload).

並列關鍵字

Integer transform ； CSD data representation ； Reversible data hiding ； Histogram

參考文獻

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