Directional Pixogram: A New Approach for Video Steganography

A video signal can be expressed as a 3D signal where the rows and columns of pixels represent the first and the second dimension, while the third dimension is the time. The 3D nature of video signals has produced an additional source of data redundancy; that is, the temporal redundancy. Utilizing signal redundancy is the fundamental driving force for steganography techniques. In this paper, the Directional Pixogram is proposed to optimally exploit the redundancy in a video segment. The Directional Pixogram is a 1D vector that starts from a certain initial position and then grows in the direction of the motion vector associated with that initial position. It is expected that this temporal vector will contain highly correlated pixels. Therefore, the Discrete Cosine Transform (DCT) can express this vector within few significant DCT coefficients leaving a large amount of insignificant DCT coefficients. Thus, experimental results have shown that the proposed Directional Pixogram is able to obtain outstanding stego quality while hiding with very high hiding capacities.