@conference {uvigo:quantized, title = {Quantized Projection Data Hiding}, booktitle = {IEEE International Conference on Image Processing (ICIP)}, year = {2002}, month = {September}, address = {Rochester (NY), USA}, keywords = {data-hiding, watermarking}, author = {Fernando P{\'e}rez-Gonz{\'a}lez and F{\'e}lix Balado} }