spreading the watermark bits over a image using spreadspectrum

can anyone help to write the code for the following. B denote the binary watermark bit string having length of L bits.B= {b1,b2,b3.. bL}, where i b (1,0). I=host image with length Q. A binary valued code pattern of length Q is used to spread each watermark bit. let P denote set of l code pattern each of length Q. can anyone help me to execute this by performing the following operation