Watermarking Algorithm for Print-Scan Based on Wavelet-Packet Transform and Error Diffusion

A watermarking algorithm for print-scan based on wavelet packet transform and error diffusion is introduced.This method manipulates the original image by three layer wavelet packet transform,and adds watermark onto the low frequency subband by high frequency components,then the image by modified noise-balanced error diffusion halftone image screening.The experimental results show that the algorithm is high robust against for print-scan.