An adaptive watermark algorithm based on the relativity of wavelet coefficients proposed.Firstly

the original image and the watermark image are decomposed by wavelet transform;the second step is that selecting the sub-bands of embedding watermark and dividing the sub-bands into blocks

the size of block is 2×2;the next step is to construct the watermark of the block according to the relativity of four consecutive wavelet coefficients in each block.Finally

the watermark embedding strength is regulated by the human visual system model

therefore

the method gained robustness and imperceptibility.Two different images are selected to embed watermarking in the paper

according to the experimental results

the algorithm can withstand attacks such as JPEG compression

adding Gaussian noise and Salt and Pepper noise

cropping and so on.At the same time

the algorithm can withstand rotation attack at some degree.