Improved halftone image data hiding with intensity selection

In this paper, we propose a novel algorithm called intensity selection (IS) that can be applied to three existing halftone image data hiding algorithms DHST, DHPT and DHSPT to achieve improved visual quality. The proposed IS algorithm generalizes the hidden data representation and select the best location out of a set of candidate locations for the application of DHST/DHPT/DHSPT. It chooses pixel locations that are either very bright or very dark. The IS requires the inverse-halftoned image which implies potentially high computation requirement. Experiments suggest that significant improvement in visual quality can be achieved.