Abstract
Pixel-Value Differencing (PVD) for information hiding is proposed by Wu and Tsai. It is capable to hide large amount of data by using adaptive scheme. This paper presents a modified scheme based on Wu-Tsai's algorithm. The proposed method exploits the ability of performing embedding process twice for every pair of pixels. The sum and difference of block pixels facilitates restoring of the first stego-image. Results show an improvement in stego-image capacity by more than 30% compared with the original scheme. Comparing Stego-images after using both schemes illustrates that the proposed method can hide much more data information and maintain good visual quality.