Data hiding in ordered dithered halftone images

In this paper, we propose a novel method called data hiding ordered dithering (DHOD) to hide a relatively large amount of invisible watermarking data in ordered dithered halftone images while retaining good visual quality. We assume that both the original image and the ordered dithering screen are available. The proposed method includes two techniques:screen modification andthreshold selection. First, one out of everyM pseudo-random locations is selected usingthreshold selection to embed one bit of hidden data. Second, at the selected locations,screen modification is applied to change the ordered dithering screen in a local neighborhood to achieve the desired data hiding while attaining good visual quality. Some custom-made quality measures are proposed to evaluate DHOD. Simulation results suggest that DHOD can hide a large amount of data while maintaining good visual quality.