Efficient double-layered steganographic embedding

Adding/subtracting one into/from pixel values can be used to hide secret data into the least significant bit plane of a cover image. A double-layered embedding scheme that introduces the wet paper coding mechanism to determine the selection of addition or subtraction is proposed. In this way, the second LSB plane can be exploited to carry additional secret data, leading to improved embedding efficiency and embedding rate. By combining the double-layered embedding method with various steganographic coding techniques, even higher embedding efficiencies can be achieved while keeping low embedding rates