ABSTRACT
Adaptive steganographic of images uses the texture characteristics of itself and
human visual senses, in the condition of that not affect a person visual, embedded a lot
of seceret information under the premise of image texture in the region which is also
human visual not sensitive and in the image smooth area which is also human visual
sensitive area not embedded or embedded information less as far as possible.
Based on the study of the existing adaptive image steganographic algorithm, three
adaptive steganographic algorithms ware put forward on this paper, and further analysis
of those algorithms, the proposed algorithms mainly include the following aspects:
Binary images can be hidden information, in the alternate edge of black and white
area of a binary image to embedded secret information, not easy to cause the human eye
on the vision abnormalities. Gray images can be segmented to eight planes, each plane
can regard as a binary image, combining matrix code we presents a gray image double
steganographic algorithm, the first layer embedded in the gray image plane using a
binary image hidden information method, the second is to embed image direction
coding embedded information. The algorithm addressed in the paper shows the good
performance of simple implementation, large information capacity and high resolution
picture, and also can fight RS attacks.
Most of the gray images steganographic adaptive algorithms is use the difference
value between of pixels to embedded information, combined with the method of the
binary images edge look for the edge of pixels, we puts forward the gray image
steganographic algorithm use the difference value between adjacent pixels to hiding
secret information , this algorithm has good subjective visual .
Gray image pixels difference algorithms are most of based on image block,
according to the difference values between each block to embedded information. And
this paper using gray image pixels piece of characteristics between pixels, define image
edges different value on image block, according to each pixel blocks of the texture
characteristics, embedded different bit secret information. The algorithm addressed in
the paper shows the good performance of simple implementation, large information
capacity and high resolution picture, and also can fight RS attacks.
This dissertation mainly studies the adaptive image steganographic, use the images
characteristics of itself to hidden secret information in the airspace of image, put
forward three adaptive image steganographic algorithms based on gray images, the
algorithm is still has many shortcomings, which needs to be further research.
Key Word: information hiding, Adaptive steganographic, EMD, RS