An Image Watermarking Algorithm with Adaptively Determining the Number of Information Bits to Be Embedded ⋆

The numbers of information bits to be embedded into each block are equal in current image watermarking algorithms. The sensitive positions are overly embedded while the insensitive ones are not fully utilized with a certain amount of information bits, which limits the effect of embedding the information. A new image watermarking algorithm is proposed by adaptively determining the number of information bits to be embedded into the blocks. It is also considered when embedding the information that the sensitivity of same texture or brightness on human eye is not same in different circumstances. The original image is divided into blocks, and the number relies on the frequency-domain of the blocks. Experimental results show that the algorithm can well promote the invisibility of the watermarks with a certain amount of information bits, according to which the amount of information bits can be larger with the same invisibility.