Reversible Image Mosaic Technology Providing Large Protection Size and High Image Quality
Huaibo Sun, Hong Luo, Yan Sun and Mohammad S. Obaidat
Ensuring the security of data transmitted in mobile ad hoc network (MANET) has become an urgent problem to be solved. Therefore, this paper presents a reversible image mosaic technology that can provide a large protection size and a high image quality to protect the privacy information in the image, where the upper bound of the region of interest (ROI) that we can protect can be predicted according to users requirements about peak signal to noise ratio (PSNR) and the preset compression rate of privacy data. The ideal carrier on the non-ROI of the image is found based on the change of roughness (C R) and the PSNR for the high PSNR and large protection size. Finally, the stego image with mosaics is saved in lossless format after the privacy data being hidden with LSB substitution. The method used for computing the upper bound of the size of protected ROIs is presented. A twice-run length encoding algorithm is proposed to compress the privacy data. In addition, we also discuss the relationship between the C R and PSNR, prove the ranges of different |C R|s, and explore the influences exerted on PSNR by different |C R|s. Extensive experimental results show that the upper bound of protected ROI and the relationship between the C R and PSNR are correct. Compared with other algorithms, the average value of PSNR provided by the proposed algorithm is up to 41.54% higher than that of the comparison algorithms while our protection size is also higher. Moreover, the average relative distortion caused by each mosaic block is also less compared to other algorithms.
Keywords: Mobile ad hoc network (MANET), reversible image mosaic, upper bound of protection size, PSNR, change of roughness, data adjustment