An Information Hiding Scheme Based on Pixel-Value-Ordering and Prediction-Error Expansion with Reversibility

This paper proposes a data hiding scheme based on pixel-value-ordering and predication-error expansion. In a natural image, most neighboring pixels have similar pixel values, i.e. the difference between neighboring pixels is small. Based on the observation, we may predict a pixel’s value according its neighboring pixels. The proposed scheme divides an image into non-overlapping blocks each of which consists of three pixels, and pixels in a block are sorted in a descending order. Messages are embedded into two difference values, where one is between the largest and medium pixels and the other is between the smallest and medium ones. In the embedding process, difference values equal to 0 or greater than 1 are unchanged or increased by 1, respectively, and those equal to 1 are also unchanged or increased by 1 if the message bit to be embedded is equal to 0 or 1, respectively. Calculating the difference value, one may extract a message bit of 0 or 1 if it is equal to 1 or 2, respectively. Recovering pixels is done by decreasing those difference values by 1 if they are equal to or larger than 2. Experimental results demonstrate that the proposed scheme may provide much larger embedding capacity, comparing to existing study, and a satisfied image quality. Keywords—Reversible data hiding; Pixel-value-ordering; Prediction-error expansion