Digital Image Hidden in an Image Using n-Graylevel Encoding

This paper proposed an n-graylevel encoding method to hide digital images. First of all, transform every pixel value of a covert image into n-graylevel codes, and then these n-graylevel codes are embedded into a host image with a specific encoding rule. The proposed method use n-graylevel encoding method can hide digital images into a host image to form an overt image with n-graylevel codes. All pixel elements of the overt image can be found into five categories, which are respectively as identification codes, image graylevel codes, dimension codes, n-graylevel codes, and information codes. The proposed method can hide digital images, good security, fast calculation, saving space, and the overt image is almost the same as the host image. The covert image can be directly decoded from the overt image not using the host image, and then the decoded covert image and the original covert image are all the same.