On steganalysis of plus-minus one embedding of continuous-tone images
Ping Wah Wong, Hong Chen, Zhongjue Tang · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2005
In this paper, we examine a method for estimating the embedding rate (or equivalently, the length of the hidden message) for plus-minus one embedding. The plus-minus one method embeds information into the least significant bit of the carrier by either adding or subtracting one from a pixel when the LSB of the pixel value is not equal to the message bit. The decision of adding or subtracting one is determined randomly with equal probability for each case. In this paper, we formulate the plus-minus one embedding procedure as a state transition between two sequences of sets. Given an image that possibly contains plus-minus one embedding, an original image is estimated using an adaptive wavelet denoising algorithm. The stego image is classified into busy and non-busy areas, and then parameters with respect to the state transition are calculated from the non-busy areas in both the stego image and the estimated original image. The embedding rate is then estimated using a symmetric form of divergence (Kullback-Leibler distance). Experimental results using the proposed algorithm are shown.