A lossless data hiding scheme based on three-pixel block differences

This paper proposes a data hiding scheme that losslessly embeds a message into a cover image using the two differences—between the first and the second pixel as well as between the second and the third pixel—in a three-pixel block. In the cover image, an absolute difference between a pair of pixels is selected to embed the message if the number of pixel pairs with the difference in the image is the largest. To embed a bit “1” or “0”, the selected difference is increased by 1 or left unchanged, respectively. In the best case, a three-pixel block can embed two bits “11” and only the central pixel needs to be increased or decreased by 1. The average payload capacity among the test images can be up to 2.08 bits per pixel (bpp).