I. Introduction
Digital image steganography aims to embed secret message into redundant data of digital images for covert communication. The affection on the visual effect of cover images is so slight that secret messages are concealed. Therefore, steganalysis technologies focusing on revealing the presence of the secret messages and extracting them are becoming more and more important. In recent years, with the rapid development of steganography, adaptive steganography methods such as HUGO, MOD [1], J-UNIWARD [2], etc. have been proposed. These adaptive steganography methods constrain the embedding changes to the complicated texture regions which are difficult to model, so they have outstanding anti-detection ability. Many different steganalysis methods have been proposed to detect adaptive steganography methods. For most methods, feature extraction and classifier design are two key elements that affect the detection accuracy.