Abstract
A simple data hiding technique for binary images is proposed. It is a “pattern” based method instead of block based like most of others. The embedding rules are as follows: If the number of black pixels in a pattern is even, it implies that this pattern embeds a “0”. If the number of black pixels in a pattern is odd, it implies that this pattern embeds a “1”. It adds one black pixel at the left or right hand side of the pattern to fit the embedding rules. We use a weighting mechanism to determine which side we can add well. Before embedding, we apply a pre-processing to the binary image to avoid the ambiguous problem. The pre-processing may increase capacity of the image. This method is suit for binary images, especially good for text document, Chinese calligraphy, and hand-writings. We can extract the data from the binary image without prior knowledge of the original size of the image.