In this paper, we propose a practical method to estimate the payload rate for individual cover before stego embedding. The proposed method is adopted to the additive distortion model. The a priori knowledge functions employed in the method contains the relation function of steganalyzer's detection error and stego distortion (PE– D), and the relation function of payload rate and distortion(D–α) of the given cover. As it is not suitable to measure the stego security with stego distortion, we adopt PE as the security metric. With the sender's expected PE, the role of PE– D function is to calculate the corresponding D, and then sender can solve out his expectedα with D–α function for the cover. The PE – D function is acquired before estimating phase. During the estimating, the most time-consuming part is calculating the D–α function for the cover, which costs 1 time of stego embedding. Our method is an efficient solution for estimating the secure payload rate.
Sai Ma, Xianfeng Zhao, Qingxiao Guan, Chengduo Zhao, "The A Priori Knowledge Based Secure Payload Estimation for Additive Model" in Proc. IS&T Int’l. Symp. on Electronic Imaging: Media Watermarking, Security, and Forensics, 2017, pp 16 - 21, https://doi.org/10.2352/ISSN.2470-1173.2017.7.MWSF-320