Data hiding in binary images for annotation by parity check

A simple data hiding technique for binary images is proposed. It is a "pattern" based method instead of most conventional block based methods. 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 by using a weighting mechanism. 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 size of the cover image