REVERSIBLE DATA HIDING BASED ON PIXEL-BASED PIXEL VALUE ORDERING PREDICTOR AND EMD

In this paper, we improved the reversible data hiding method of Qu’s et al. The original image is divided into overlapped equalsize blocks (2x2). Each of block is used to predict a pixel. Then a histogram is constructed from the different value between the original pixel and  the prediction pixel. In order to increase thecapacity, the proposed method combination with EMD table to change the histogram. According to Qu’s method, each pixel satisfies only one bit of information is embedded. In our method, by using the EMD table, each pair of eligible pixels can embed three bits of information. Experimental results show that the proposed  method increases 1.5 times the hidden performance while the image quality changes negligibly.