@conference {wiamis04:dm, title = {Improved Binary Dither-Modulation with perceptual constraints}, booktitle = {International Workshop on Image Analysis for Multimedia Interactive Services (WIAMIS)}, year = {2004}, month = {April}, address = {Lisboa, Portugal}, keywords = {data-hiding, watermarking}, author = {Fernando P{\'e}rez-Gonz{\'a}lez and Pedro Comesa{\~n}a} }