CN104822067A - Image and video information hiding method based on block scrambling and non-linear conversion - Google Patents

Abstract

The invention discloses an image and video information hiding method based on block scrambling and non-linear transformation, comprising the following steps: 1) performing block rearrangement on each frame of the video; 2) performing segmentation on each sub-block Perform a nonlinear transformation. 3) Use the methods of step 1) and step 2) to restore the encrypted video. The method for hiding and restoring image and video content of the present invention is simple in overall process, and has a good hiding effect on images and videos.

Description

An Image and Video Information Hiding Method Based on Block Scrambling and Nonlinear Transformation

technical field

The invention relates to image and video processing technology, in particular to an image and video information hiding method based on block scrambling and nonlinear transformation.

Background technique

The rapid development of information network technology on a global scale has facilitated the communication and exchange between people. With the help of computer networks, people can easily and quickly transmit digital information to all parts of the world, and this assignment and transmission can be almost lossless.

The side effects brought about by this convenience also arise as the times require. In the process of transmitting information, some individuals and groups intercept the information without the permission of the original author of the information, and some relatively confidential images or video information can be seen at a glance. The security of information is destroyed, and the secret transmission technology of information begins to develop in this situation.

Information (including images and videos) hiding utilizes the sensory redundancy of human sensory organs for digital signals, uses digital media and digital files as carriers, and hides secret information in the carrier information through certain algorithms, but it is not easy to be detected by the human perception system. More awareness, so as to achieve the purpose of covert communication.

Contents of the invention

The technical problem to be solved by the present invention is to propose an image information hiding method based on block scrambling and nonlinear transformation, which can hide target information quickly and effectively without human intervention in the process of hiding content.

Technical scheme of the present invention is as follows:

1) Block rearrangement is performed on each frame of the video; 2) Non-linear changes are performed on each divided sub-block. 3) Use the method of step 1) and step 2) to restore the encrypted image and video.

Description of drawings

Fig. 1 is the flow chart of the image and video information hiding method based on block scrambling and nonlinear transformation;

Figure 2 is the result of block rearrangement of a certain frame of image in the video;

Figure 3 is the result of information hiding for a certain frame image in the video.

Detailed ways

1) Perform block rearrangement for each frame of the video. The delineation of the sub-block size is automatically completed by the system, there is no artificial setting during execution, and the specific division rules are fixed, which is suitable for videos of any size. The specific division rules are generally divided into two categories. Because the case that there are prime numbers in the rows and columns of the video cannot be ruled out, it is divided into two cases: prime number rows (columns) and non-prime number rows (columns). For non-prime number rows (columns), we factorize the rows (columns) and count the number of factors other than 1. If the number is greater than or equal to 3, the number of divided rows (columns) is determined as in formula (1) Shown:

num=max(v)*min(v) (1)

Otherwise, the number is fixed as shown in formula (2):

num=min(v) (2)

Among them, num represents the number of rows (columns) to be divided, v represents the set of all factors except 1 generated after factoring the number of rows (columns), max(v) represents the maximum value in v, min( v) represents the minimum value in v. For a prime number row (column), as long as 1 is subtracted, the original prime number row (column) becomes a non-prime number row (column), and the processing uses the previous method, and additional processing is performed on the extra row (column). The block rearrangement order of each frame of the video is different, and is randomly generated by the system. The ordering information is saved in the form of text, and there is no artificial setting, which greatly improves the security of information. The specific rearrangement method is to arrange the divided sub-blocks into a 1*n matrix in the order of increasing row and column numbers, where n represents the number of sub-blocks, randomly rearrange the columns of the matrix, and then sort them by row The number of blocks (columns) restores the matrix to the size of the original image, which has the effect of scrambling.

2) Perform nonlinear changes to each sub-block divided in step 1). Non-linear changes are used for the change of the pixel value of each pixel in each layer of the sub-block (including the extra row (column) generated by processing the prime number row (column)). It can be expressed simply by formula (3)

E _i (x, y) = f(P _i (x, y)) (3)

Where E _i (x, y) represents the pixel value after nonlinear transformation, P _i (x, y) represents the pixel value before nonlinear transformation, f represents a nonlinear transformation, and i represents the color image r, g, b One of the three layers, (x, y) represents the coordinates of the pixel in the sub-block.

3) The method for recovering the encrypted image and video is to use the sub-processes of step 2) and step 3) again, but step 3) is properly modified in the recovery process, and the recovery process is similar to the encrypted process.

Claims (4)

1. a kind of image and video information hiding method based on block scrambling and nonlinear transformation, it is characterized in that: comprise the following steps: 1) Carry out block rearrangement for each frame of the video; 2) performing non-linear transformation on each divided sub-block; 3) Use the method of step 1) and step 2) to restore the encrypted video. 2. the image and video information hiding method based on block scrambling and non-linear transformation according to claim 1, is characterized in that: step 1) carries out block rearrangement method to each frame of video as follows: The method of dividing a frame of image, that is, the delineation of the sub-block size is automatically completed by the system, there is no artificial setting during execution, and the specific division rules are fixed and suitable for videos of any size; the specific The division rules are generally divided into two categories. Because it cannot be ruled out that there are prime numbers in the rows and columns of the video, it is divided into two cases: prime number rows (columns) and non-prime number rows (columns). For non-prime number rows (columns), we Rows (columns) are factorized, and the number of factors other than 1 is counted. If the number is greater than or equal to 3, the number of divided rows (columns) is determined as shown in formula (1): num=max(v)*min(v) (1) Otherwise, the number is determined as shown in formula (2): num=min(v) (2) Among them, num represents the number of rows (columns) divided, v represents the set of all factors except 1 generated after factoring the number of rows (columns), max(v) represents the maximum value in v, min( v) represents the minimum value in v; for a prime number row (column), as long as 1 is subtracted, the original prime number row (column) becomes a non-prime number row (column), and the previous method is used for processing, and the extra row (column) ) and perform additional processing; the block rearrangement order of each frame of the video is different, and they are all randomly generated by the system. The sorting information is saved in the form of text, and there is no artificial setting, which greatly improves The specific rearrangement method is to arrange the divided sub-blocks into a 1*n matrix in the order of increasing row and column numbers, where n represents the number of sub-blocks, and randomly rearrange the columns of the matrix row, and then restore the matrix to the size of the original image according to the number of blocks in the row (column) to achieve a disruptive effect. 3. the method for image and video information hiding based on block scrambling and nonlinear transformation according to claim 1, characterized in that: in step 2), the method of carrying out nonlinear transformation to each sub-block segmented is as follows: Non-linear changes are used for the change of the pixel value of each pixel in each layer of the sub-block (including the extra row (column) generated by processing the prime number row (column)). It can be expressed simply by formula (3) E _i (x, y) = f(P _i (x, y)) (3) Where E _i (x, y) represents the pixel value after nonlinear transformation, P _i (x, y) represents the pixel value before nonlinear transformation, f represents a nonlinear transformation, and i represents the color image r, g, b One of the three layers, (x, y) represents the coordinates of the pixel in the sub-block. 4. the image and video information hiding method based on block scrambling and non-linear transformation according to claim 1, is characterized in that: in step 3), the method for restoring encrypted video is to use step 2) and step 3 again ) is a sub-process, but step 3) is properly modified in the recovery process, and the recovery process is similar to the encryption process.