On the Positioning of Moderately Significant Bit Data Hiding in High-Definition Images

Abstract

Mobile services have seen a shift from voice services toward visual stimuli-based services ranging from mobile imaging over mobile gaming to upcoming mobile extended reality applications. In this paper, given the increased resolutions of the related mobile multimedia formats, we propose and examine positioning strategies for light-weight data hiding of secret images in moderately significant bits of high-definition (HD) cover images. Apart from linear and random positioning, visual attention mechanisms of the human visual system are addressed by separately utilizing either the background or center of the HD cover image for data hiding. A performance assessment of these positioning strategies is conducted in terms of the peak-signal-to-noise ratio (PSNR), structural similarity (SSIM) index, and visual information fidelity (VIF). It is shown that HD cover images indeed can carry more than a single secret image until noticeable quality loss is observed. Further, it is revealed that linear positioning of secret images in the whole, background, or center of HD cover images outperforms random positioning. As for the utilized performance metrics, it has been observed that PSNR cannot differentiate among the positioning strategies as it measures pixel-by-pixel differences and hence removes the impact of the position of the hidden data. As for the two quality metrics, compared to the SSIM index, VIF is found to stronger differentiate among the performance of the considered positioning strategies.