植基於雙影像之可逆式藏入法使用中間對折策略與區間量表

Abstract

Lu、Wu及Huang學者於2015年提出使用中間對折策略之可逆式雙影像藏入法，該方法設定了一個固定的數值決定藏入量，接著將藏入訊息轉為十進制並使用中間對折策略，減少數值的大小，而後對切數值將之藏入兩張偽裝影像中。作者的方法固定藏入量，因此，本論文透過區間量表變動藏入量，所提方法先將影像切割成1×2不重疊的區塊，接著透過區塊內相鄰像素差值帶入區間量表得知所能藏入的訊息量，來達成保持影像品質，同時藏入更多訊息的目的。實驗結果顯示本文所提出方法能夠藏入更多的訊息。Lu et al. proposed a dual-image-based reversible data hiding method using center folding strategy in 2015. The method used a fixed value to decide the hiding capacity. The secret data transformed by decimal system and folded by using center folding strategy. The folded secret data then hidden into two stego-images. The hiding capacity of Lu et al.'s scheme is fixed that is non-flexibility. Thus, this paper applies an interval scale strategy to dynamically change the hiding payload. The proposed scheme divides the original image into several non-overlap blocks sized 1×2. Then, the scheme calculates the difference between two pixels in the block. The interval scale table is used to determine the hiding bits of the block to control the image quality and to obtain higher hiding capacity. The experimental results show that the proposed scheme can get higher capacity.