Line covering method and its applications in steganography and steganalysis

Image features are widely used in steganography and steganalysis. In steganography, image features are used to better understand the image, in order to achieve higher quality. In steganalysis, image features are used to show the changes caused by steganography. This paper presents a new method, line covering, to evaluate the smoothness of an image. A new image feature, smoothness based on line covering, is proposed and we discuss its applications in steganography and steganalysis. This feature can better show the smoothness features in different directions whereas many other image features ignore the direction of features. A steganalysis based on this feature is proposed which has high accuracy in detecting a histogram modification steganographic techniques. And it can easily control the false rejection rate and false acceptation rate. This paper also discusses its application in steganography, and how it can solve the problem of choosing a pairing direction in the steganography based on difference expansion (DE).