WO2022199180A1

WO2022199180A1 - Method for dynamic image steganography, apparatus, device, and storage medium

Info

Publication number: WO2022199180A1
Application number: PCT/CN2021/141728
Authority: WO
Inventors: 万璐敏; 黄璐璐
Original assignee: 天翼云科技有限公司
Priority date: 2021-03-23
Filing date: 2021-12-27
Publication date: 2022-09-29
Also published as: CN115115497A

Abstract

Provided in the present application are a method for dynamic image steganography, an apparatus, a device, and a storage medium. The method comprises: obtaining a color indexed image, comprising an index matrix and a palette, of each carrier image among a plurality of carrier images acquired from a dynamic image; modifying each value in the index matrices, and obtaining modified index matrices; indexing the palettes according to the index matrices, and obtaining pixel values of each channel of each carrier image; indexing the palettes according to the modified index matrices, and obtaining modified pixel values of each channel of each carrier image; obtaining a distortion cost matrix for each carrier image according to the pixel values of each channel of each carrier image and the modified pixel values of each channel of each carrier image; embedding information to be steganographically concealed into the index matrices on the basis of the distortion cost matrix for each carrier image, and obtaining a steganographic index matrix for each carrier image; and obtaining a plurality of steganographic images according to the steganographic index matrix for each carrier image and the palette of each carrier image, so as to be combined and form a dynamic steganographic image.

Description

Dynamic image steganography method, device, device and storage medium

This application claims the priority of the Chinese patent application with the application number 202110309029.8 and the invention titled "Dynamic Image Steganography Method, Apparatus, Equipment and Storage Medium" filed with the China Patent Office on March 23, 2021, the entire contents of which are by reference Incorporated in this application.

technical field

The present application relates to the technical field of information security, and in particular, to a dynamic image steganography method, apparatus, device, and readable storage medium.

Background technique

Steganography is an important branch in the field of information hiding technology, which can achieve the purpose of covert communication by embedding secret messages into images, audio, video, text and other files. Image has the characteristics of universality, easy access and sufficient redundant data. Image steganography technology using it as the information hiding carrier is one of the research focuses in this field. Image steganography methods in the related art are proposed on static images, and are only applicable to true-color images, and there is no steganography method based on dynamic index images.

As mentioned above, how to provide a steganography method based on dynamic index images has become an urgent problem to be solved.

The above information disclosed in this Background section is only for enhancement of understanding of the background of the application and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.

SUMMARY OF THE INVENTION

The purpose of the present application is to provide a dynamic image steganography method, device, device and readable storage medium, at least to a certain extent, to overcome the problem that the static image steganography method in the related art is not suitable for dynamic index images.

Other features and advantages of the present application will become apparent from the following detailed description, or be learned in part by practice of the present application.

According to an aspect of the present application, a dynamic image steganography method is provided, comprising: obtaining a color index image of each frame of carrier images in a multi-frame carrier image, wherein the multi-frame carrier images are obtained from the dynamic image, the color The index image includes an index matrix and a palette; modify each value in the index matrix to obtain a modified index matrix; index the palette according to the index matrix to obtain the pixel value of each channel of each frame of carrier image ; Index the palette according to the modified index matrix to obtain the modified pixel value of each channel of each frame carrier image; According to the pixel value of each channel of the each frame carrier image and each channel of the each frame carrier image Obtain the distortion cost matrix of each frame carrier image based on the modified pixel values of The steganographic index matrix of each frame of carrier image and the palette of each frame of carrier image are used to obtain multiple frames of steganographic images to synthesize dynamic steganographic images.

According to an embodiment of the present application, the method further includes: for each channel of each frame of the carrier image, using a high-pass filter to filter the pixels of each channel and then obtaining the absolute value of the filtering result; using a low-pass filter to filter the The absolute value of the result is smoothed to obtain the reciprocal of the final residual, and the distortion cost value of each channel of each frame of carrier image is obtained respectively; Obtaining the distortion cost matrix of each frame carrier image by modifying the pixel value of each channel includes: respectively obtaining the difference between the pixel value of each channel of each frame carrier image and the modified pixel value; The distortion cost matrix of each frame carrier image is obtained from the difference with the modified pixel value and the distortion cost value of each channel of each frame carrier image.

According to an embodiment of the present application, the obtaining a color index image of each frame of carrier images in the multi-frame carrier images includes: acquiring an initial index matrix and an initial palette of each frame of carrier images; The palette is reordered according to the squared sum of each channel value to obtain the palette of each frame of carrier image; the index matrix of each frame of carrier image is obtained according to the initial index matrix of each frame of carrier image, the initial palette, and the palette ; Described obtaining the distortion cost matrix of each frame carrier image according to the difference between the pixel value of each channel of the frame carrier image and the modified pixel value and the distortion cost value of each channel of the each frame carrier image includes: obtaining: The square sum of the difference between the pixel value of each channel of the each frame carrier image and the modified pixel value; averaging the distortion cost value of each channel of the each frame carrier image to obtain the total distortion cost value of each frame carrier image; The total distortion cost value of each frame of carrier image is multiplied by the square sum of the difference between the pixel value of each channel and the modified pixel value to obtain a distortion cost matrix of each frame of carrier image.

According to an embodiment of the present application, the method further includes: acquiring a color index image of a carrier image of a current frame, where the carrier image of the current frame is any frame after the carrier image of the first frame in the multi-frame carrier images; Perform grayscale conversion on the color index image of the carrier image of the current frame to obtain the grayscale image of the carrier image of the current frame; obtain the color index image of the carrier image of the previous frame of the carrier image of the current frame; The index image is converted into grayscale to obtain the grayscale image of the previous frame of the carrier image; the total distortion cost value of each frame of the carrier image is multiplied by the sum of the squares of the difference between the pixel value of each channel and the modified pixel value, Obtaining the distortion cost matrix of the carrier image of each frame includes: squaring the grayscale image of the carrier image of the current frame and the grayscale image of the carrier image of the previous frame, and obtaining each pixel in the carrier image of the current frame. When the luminance variation of a pixel in the current frame carrier image is greater than the luminance variation threshold, compare the total distortion cost value of the current frame carrier image with the value of each channel of the pixel The pixel value is multiplied by the square sum of the difference of the modified pixel value to obtain the color change amount of the pixel, so as to obtain the distortion cost matrix of the carrier image of each frame.

According to an embodiment of the present application, the total distortion cost of each frame of carrier image is multiplied by the sum of the squares of the difference between the pixel value of each channel and the modified pixel value to obtain the distortion cost of each frame of carrier image The matrix includes: obtaining a brightness change threshold; obtaining a distortion cost weight, where the distortion cost weight is a value greater than 1; when the brightness change of a pixel in the current frame carrier image is not greater than the brightness change threshold, the The total distortion cost value of the carrier image of the current frame is multiplied by the square sum of the difference between the pixel value of each channel of the pixel and the modified pixel value, and then multiplied by the distortion cost weight to obtain the color change amount of the pixel to obtain the Distortion cost matrix for each frame of carrier image.

According to an embodiment of the present application, the method further includes: performing a binarization process on the color index images of the carrier images of each frame to obtain a binary image of the carrier images of each frame; extracting the binary images of the carrier images of each frame The boundary information of the value image, obtain the boundary information value of each pixel of each frame carrier image; obtain the true boundary value; according to the pixel value of each channel of each frame carrier image and the pixel value of each channel of each frame carrier image and the frame carrier image Modifying the pixel value to obtain the distortion cost matrix of the carrier image of each frame includes: for each pixel of the carrier image of each frame, when the boundary information value of the pixel is equal to the true boundary value, according to the pixel value of each channel of the pixel and the modified pixel value to obtain the distortion cost of this pixel to obtain the distortion cost matrix of the carrier image of each frame.

According to an embodiment of the present application, the method further includes: obtaining a preset distortion value; obtaining the pixel value according to the pixel value of each channel of the carrier image of each frame and the modified pixel value of each channel of the carrier image of each frame The distortion cost matrix of each frame of carrier image further includes: for each pixel of each frame of carrier image, when the boundary information value of the pixel is not equal to the true boundary value, the obtained distortion cost of the pixel is the preset distortion value, to obtain the distortion cost matrix of the carrier image of each frame.

According to yet another aspect of the present application, there is provided a dynamic image steganography device, comprising: an index image obtaining module configured to obtain a color index image of each frame of carrier images in a multi-frame carrier image, the multi-frame carrier images from the Obtained from a dynamic image, the color index image includes an index matrix and a palette; an index value modification module is used to modify each value in the index matrix to obtain a modified index matrix; the first pixel value obtaining module, using indexing the palette according to the index matrix to obtain pixel values of each channel of the carrier image of each frame; a second pixel value obtaining module for indexing the palette according to the modified index matrix to obtain each frame The modified pixel value of each channel of the carrier image; the distortion cost obtaining module is used to obtain the pixel value of each frame of the carrier image according to the pixel value of each channel of the carrier image of each frame and the modified pixel value of each channel of the carrier image of each frame. Distortion cost matrix; a steganographic index matrix obtaining module, used for embedding the information to be steganographic into the index matrix based on the distortion cost matrix of each frame of carrier image, to obtain the steganographic index matrix of each frame of carrier image; steganographic image acquisition The module is configured to obtain multiple frames of steganographic images according to the steganographic index matrix of the carrier images of each frame and the palette of the carrier images of each frame, so as to synthesize dynamic steganographic images.

According to an embodiment of the present application, the device further includes: a high-pass filtering module, configured to filter the pixels of each channel with a high-pass filter for each channel of each frame of the carrier image, and then obtain the absolute value of the filtering result; the channel distortion cost The calculation module is used for smoothing the absolute value of the filtering result by using a low-pass filter to obtain the final residual and then taking the reciprocal to obtain the distortion cost value of each channel of each frame of carrier image; the distortion cost obtaining module includes: The pixel difference module is used to obtain the difference between the pixel value of each channel of each frame carrier image and the modified pixel value respectively; the image distortion cost calculation module is used to modify the pixel value according to the pixel value of each channel of each frame carrier image and the modified pixel value. The difference of the values and the distortion cost value of each channel of the carrier image of each frame obtains the distortion cost matrix of the carrier image of each frame.

According to an embodiment of the present application, the index image obtaining module includes: an initial index image obtaining module for obtaining an initial index matrix and an initial palette of each frame of carrier images; a palette updating module for converting the The initial palette of each frame carrier image is reordered according to the square sum of each channel value to obtain the palette of each frame carrier image; the index matrix update module is used for the initial index matrix and initial palette according to the initial index matrix and initial palette of each frame carrier image. , and the index matrix that palette obtains each frame carrier image; Described distortion cost obtaining module comprises: pixel change calculation module, for obtaining the square of the difference of the pixel value of each channel of described each frame carrier image and the modification pixel value And; Distortion cost value calculation module, for averaging the distortion cost value of each channel of each frame carrier image to obtain the total distortion cost value of each frame carrier image; Distortion cost matrix calculation module, for describing each frame The total distortion cost value of the carrier image is multiplied by the square sum of the difference between the pixel value of each channel and the modified pixel value to obtain the distortion cost matrix of the carrier image of each frame.

According to an embodiment of the present application, the apparatus further includes: a current carrier image obtaining module, configured to acquire a color index image of the current frame carrier image, where the current frame carrier image is the first frame carrier in the multi-frame carrier images Any frame after the image; the grayscale conversion module is used to perform grayscale conversion on the color index image of the current frame carrier image to obtain the grayscale image of the current frame carrier image; the previous frame carrier image acquisition module is used to obtain all The color index image of the previous frame carrier image of the current frame carrier image; the grayscale conversion module is also used to perform grayscale conversion on the color index image of the previous frame steganographic image to obtain the grayscale image of the previous frame carrier image. ; Described distortion cost matrix calculation module comprises: brightness change amount calculation module, is used to square after the gray scale of described current frame carrier image and the gray scale of described previous frame carrier image are made difference, obtain current frame The brightness change amount of each pixel in the carrier image; the brightness change threshold value obtaining module is used to obtain the brightness change threshold value; the distortion cost matrix calculation module is also used for the brightness change amount of one pixel in the current frame When the brightness changes the threshold value, multiply the total distortion cost value of the carrier image of the current frame and the sum of the squares of the difference between the pixel value of each channel of the pixel and the modified pixel value to obtain the color change amount of the pixel to obtain the Distortion cost matrix for the frame carrier image.

According to an embodiment of the present application, the distortion cost matrix calculation module includes: a brightness change threshold obtaining module, used to obtain a brightness change threshold; a distortion cost weight obtaining module, used to obtain a distortion cost weight, where the distortion cost weight is greater than or equal to The value of 1; the distortion cost matrix calculation module is also used to compare the total distortion cost value of the current frame carrier image with the The square sum of the difference between the pixel value of each channel of the pixel and the modified pixel value is multiplied by the distortion cost weight to obtain the color change amount of the pixel, so as to obtain the distortion cost matrix of the carrier image of each frame.

According to an embodiment of the present application, the apparatus further includes: a binarization processing module configured to perform binarization processing on the color index images of the carrier images of each frame to obtain a binary image of the carrier images of each frame; The extraction module is used to extract the boundary information of the binary images of the carrier images of each frame, and obtain the boundary information value of each pixel of the carrier image of each frame; the true boundary value acquisition module is used to obtain the true boundary value; the distortion cost The matrix calculation module is also used for: for each pixel of each frame of the carrier image, when the boundary information value of the pixel is equal to the true boundary value, obtain the distortion cost of the pixel according to the pixel value of each channel of the pixel and the modified pixel value , to obtain the distortion cost matrix of the carrier image of each frame.

According to an embodiment of the present application, the distortion cost matrix calculation module further includes: a preset distortion value acquisition module for acquiring a preset distortion value; the distortion cost matrix calculation module is further used for: for each frame of the carrier image For each pixel, when the boundary information value of the pixel is not equal to the true boundary value, the obtained distortion cost of the pixel is the preset distortion value, so as to obtain the distortion cost matrix of the carrier image of each frame.

According to yet another aspect of the present application, there is provided an apparatus comprising: a memory, a processor, and executable instructions stored in the memory and executable in the processor, the processor executing the executable instructions When implementing any of the above methods.

According to yet another aspect of the present application, a computer-readable storage medium is provided on which computer-executable instructions are stored, and when the executable instructions are executed by a processor, any one of the above methods is implemented.

The dynamic image steganography method provided by the embodiments of the present application modifies each value in the index matrix by obtaining a color index image including an index matrix and a color palette of each frame of the carrier image in the multi-frame carrier image from the dynamic image. After the modified index matrix is obtained, each frame carrier is obtained according to the pixel value of each channel of each frame carrier image obtained by the index matrix index palette and the modified pixel value of each channel of each frame carrier image obtained by modifying the index matrix index palette. The distortion cost matrix of the image, and then based on the distortion cost matrix of the carrier image of each frame, the steganographic information is embedded in the index matrix to obtain the steganographic index matrix of the carrier image of each frame, and finally the steganographic index matrix of the carrier image of each frame and the carrier image of each frame are obtained. The palette of the image obtains multiple frames of steganographic images to synthesize dynamic steganographic images, so that steganography based on dynamic index images can be realized.

It is to be understood that the foregoing general description and the following detailed description are exemplary only and do not limit the application.

Description of drawings

The above and other objects, features and advantages of the present application will become more apparent from the detailed description of example embodiments thereof with reference to the accompanying drawings.

FIG. 1 shows a schematic diagram of a system structure in an embodiment of the present application.

FIG. 2 shows a flowchart of a dynamic image steganography method in an embodiment of the present application.

FIG. 3 shows a schematic diagram of the processing procedure of step S202 shown in FIG. 2 in an embodiment.

Fig. 4 is a flowchart of a method for obtaining a distortion cost according to an exemplary embodiment.

Fig. 5 is a flowchart of an image boundary method according to an exemplary embodiment.

FIG. 6 is a frame diagram of an animation expression steganography method shown in FIGS. 2 to 5 .

FIG. 7 is a schematic diagram of a steganographic process of each frame of images shown in FIGS. 2 to 6 .

FIG. 8 is an example diagram of the results of a steganography experiment shown in FIGS. 2 to 6 .

FIG. 9 is a schematic diagram illustrating a comparison of distortion costs between the dynamic image steganography method shown in FIGS. 2 to 6 and the method in the prior art.

FIG. 10 is a schematic diagram showing the comparison of prices between the dynamic image steganography method shown in FIGS. 2 to 6 and the prior art method.

FIG. 11 is a schematic diagram illustrating a comparison of distortion costs between the dynamic image steganography method shown in FIGS. 2 to 6 and the prior art method.

FIG. 12 shows a block diagram of a dynamic image steganography apparatus in an embodiment of the present application.

FIG. 13 shows a block diagram of another dynamic image steganography apparatus in an embodiment of the present application.

FIG. 14 shows a schematic structural diagram of an electronic device in an embodiment of the present application.

Detailed ways

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments, however, can be embodied in various forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The drawings are merely schematic illustrations of the present application and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus their repeated descriptions will be omitted.

Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided in order to give a thorough understanding of the embodiments of the present application. However, those skilled in the art will appreciate that the technical solutions of the present application may be practiced without one or more of the specific details, or other methods, devices, steps, etc. may be employed. In other instances, well-known structures, methods, devices, implementations, or operations have not been shown or described in detail to avoid obscuring aspects of the application.

In addition, the terms "first", "second", etc. are used for descriptive purposes only, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first" or "second" may expressly or implicitly include one or more of that feature. In the description of the present application, "plurality" means at least two, such as two, three, etc., unless expressly and specifically defined otherwise. The symbol "/" generally indicates that the related objects are an "or" relationship.

In this application, unless otherwise expressly specified and limited, terms such as "connection" should be understood in a broad sense, for example, it may be an electrical connection or may communicate with each other; it may be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific situations.

As mentioned above, dynamic images, such as animated expressions, have different characteristics from natural images due to their special production methods, and there are some significant differences from natural images. At present, there is no steganography method for dynamic images, but a method suitable for natural images. Applying on it doesn't work very well. The steganography methods based on Syndrome-Trellis Codes (STC) applied to natural images in some related technologies cannot be applied to dynamic images at present.

Therefore, the present application provides a dynamic image steganography method, by obtaining a color index image including an index matrix and a color palette of each frame of carrier images in a multi-frame carrier image from a dynamic image, and performing a process on each value in the index matrix. After modifying and obtaining the modified index matrix, each frame is obtained according to the pixel value of each channel of each frame carrier image obtained by the index matrix index palette and the modified pixel value of each channel of each frame carrier image obtained by modifying the index matrix index palette. The distortion cost matrix of the carrier image, and then embedding the information to be steganographic into the index matrix based on the distortion cost matrix of the carrier image of each frame to obtain the steganographic index matrix of the carrier image of each frame, and finally according to the steganographic index matrix of the carrier image of each frame and each frame The palette of the carrier image is used to obtain multiple frames of steganographic images to synthesize dynamic steganographic images, so that steganography of dynamic images can be realized.

FIG. 1 shows an exemplary system architecture 10 to which the dynamic image steganography method or dynamic image steganography apparatus of the present application may be applied.

As shown in FIG. 1 , the system architecture 10 may include end devices 102 , a network 104 and a server 106 . The terminal device 102 can be various electronic devices with a display screen and supporting input and output, including but not limited to smart phones, tablet computers, laptop computers, desktop computers, wearable devices, virtual reality devices, smart homes, etc. . The network 104 is the medium used to provide the communication link between the terminal device 102 and the server 106 . The network 104 may include various connection types, such as wired, wireless communication links, or fiber optic cables, among others. The server 106 may be a server or server cluster or the like that provides various services.

The user can use the terminal device 102 to interact with the server 106 through the network 104 to receive or send data and the like. For example, the user uses the terminal device 102 to upload the information to be steganographic and the carrier dynamic image to the server 106 through the network 104 , and then obtains the steganographic dynamic image transmitted by the server 106 through the network 104 through the terminal device 102 . For another example, the user uses the terminal device 102 to input the steganographic parameters, which are then uploaded to the server 106 through the network 104 .

It should be understood that the numbers of terminal devices, networks and servers in FIG. 1 are merely illustrative. There can be any number of terminal devices, networks and servers according to implementation needs.

Fig. 2 is a flow chart of a dynamic image steganography method according to an exemplary embodiment. The dynamic image steganography method shown in FIG. 2 can be applied to, for example, the server side of the above-mentioned system, and can also be applied to the terminal device of the above-mentioned system.

Referring to FIG. 2 , the method 20 provided by this embodiment of the present application may include the following steps.

In step S202, a color index image of each frame of the carrier image in the multi-frame carrier image is obtained, the multi-frame carrier image is obtained from the dynamic image, and the color index image includes an index matrix and a color palette. A dynamic image is an image that changes shape over time, and can be an image in the Graphics Interchange Format (GIF). The multiple image data in a file is read out one by one and displayed on the screen, that is, GIF animation, such as animated expressions, animations converted from short videos, and so on.

In some embodiments, for example, an animated expression may be decomposed to obtain multiple frames of color-indexed images. It can read the animation expression, split the animation expression into multi-frame color index images, and record the basic information of each frame obtained, such as: index matrix, palette, delay time, frame number n, image height h, width w and many more.

In some embodiments, for example, after decomposing the animated expressions to obtain the initial index matrix and initial color palette of each frame of carrier image, reordering the initial color palette can obtain a new color palette, and generating a new color palette corresponding to the new color palette. The new index matrix of the color palette, the specific implementation can refer to FIG. 3 .

In step S204, each value in the index matrix is modified to obtain a modified index matrix. The index matrix is a matrix that indexes the color (pixel value) of each channel of each pixel from the palette, and modifying the index matrix is equivalent to modifying the pixel value of each channel. The modification method can be plus 1 or minus 1 and so on.

In some embodiments, the index matrix of the color index map of the current frame (the kth frame, where k is a positive integer greater than 1) can be recorded as IN _k , and the color palette as MN _k .

In step S206, the color palette is indexed according to the index matrix, and the pixel value of each channel of each frame of carrier image is obtained.

In some embodiments, for example, the red (Red, R), green (Green, G), and blue (Blue, B) channel pixel value matrices corresponding to the recorded image are respectively R1=(R1 _ij ), G1=(G1 _ij ) ), B1=(B1 _ij )∈{0,…,255} ^h×w , where h is the height of the image, w is the width of the image, the unit is the number of pixels, i is a positive integer greater than 0 and less than w, j is a positive integer greater than 0 and less than h, using the index value at the position (i, j) in the index matrix IN _k to correspond to the pixel values of the RGB channels in the palette MN _k as R1 _ij , G1 _ij , and B1 _ij , respectively.

In step S208, the modified pixel value of each channel of the carrier image of each frame is obtained by indexing the palette according to the modified index matrix.

In some embodiments, for example, the pixel value of the (i,j)th pixel after modification is R2 _ij = R1 _ij ±1, G2 _ij = G1 _ij ±1, B2 _ij = B1 _ij ±1.

In step S210, the distortion cost matrix of each frame of carrier image is obtained according to the pixel value of each channel of each frame of carrier image and the modified pixel value of each frame of carrier image. For each channel of the carrier image of each frame, a high-pass filter can be used to filter the pixels of each channel and then the absolute value of the filtering result can be obtained, and then a low-pass filter can be used to smooth the absolute value of the filtering result to obtain the final residual, and then take the reciprocal. The distortion cost value of each channel of each frame of carrier image is obtained respectively. After obtaining the distortion cost value of each channel, obtain the difference between the pixel value of each channel of the carrier image of each frame and the modified pixel value, and then according to the difference between the pixel value and the modified pixel value of each channel of the carrier image of each frame and the The distortion cost value of each channel of the carrier image is used to obtain the distortion cost matrix of each frame of carrier image.

In some embodiments, for example, when the method of FIG. 3 is used to obtain the color index image, the square sum of the difference between the pixel value of each channel of each frame of carrier image and the modified pixel value can be obtained, and then the The total distortion cost value of each frame carrier image is averaged to obtain the total distortion cost value of each frame carrier image, and then the total distortion cost value of each frame carrier image is multiplied by the square sum of the difference between the pixel value of each channel and the modified pixel value to obtain each frame carrier image. The distortion cost matrix of the image. Denote the distortion cost value of RGB channel as ρR=(ρR _ij ), ρG=(ρG _ij ), ρB=(ρB _ij ), then the distortion cost value and total distortion cost value ρ of RGB channel can be obtained by the following formula:

ρ=(ρR+ρG+ρB)/3 (4)

In the above formula, "*" is a linear convolution operation, and the convolution adopts the form of symmetrical filling so that the image size after convolution remains unchanged; H is a high-pass filter, and L ₁ and L ₂ are different low-pass filters. The method of the present application is to send the index matrix into a steganography algorithm such as the STC coding framework for steganography. After performing a ±1 operation on the index matrix, the index value changes by 1, and the color palette is reordered according to the square of the pixel value. The pixel is changed from R1(i,j), G1(i,j), B1(i,j) to R2(i,j), G2(i,j), B2(i,j), so it is necessary to obtain The real change in color is the sum of the squares of the difference between the two multiplied by the ρ. For the current kth frame, R1(i,j), G1(i,j), B1(i,j) are the palettes corresponding to the index values at the position (i,j) of the index matrix IN _k of the current frame The three-channel value in MN _k , R2(i,j), G2(i,j), B2(i,j) are the three-channel value corresponding to the new index after the index value ±1, then the current frame can be obtained The final distortion cost value ρ _t (i, j) of the pixel at position (i, j) is:

ρ _t (i,j)=ρ·((R1(i,j)-R2(i,j)) ² +(G1(i,j)-G2(i,j)) ² +(B1(i, j)-B2(i,j)) ² ) (5)

In some embodiments, when the method of FIG. 3 is used to obtain the color index image, after obtaining the square of the difference between the pixel value of each channel of each frame of carrier image and the modified pixel value, the The distortion cost value is multiplied by the square of the difference between the pixel value of each channel and the modified pixel value, and then the products of the three channels are summed to obtain the distortion cost matrix of each frame of carrier image.

In some embodiments, when the final distortion cost value of each pixel is obtained, the final distortion cost value calculated as in Equation (5) can be corrected by judging whether the change of pixels between frames is suitable for hiding information. Refer to Figure 4.

In step S212, the information to be steganographic is embedded in the index matrix based on the distortion cost matrix of each frame of carrier image, and the steganographic index matrix of each frame of carrier image is obtained. The secret information can be embedded by binary steganographic coding, such as STC coding, the distortion cost matrix, index matrix and secret value composed of the distortion cost function value of each pixel point calculated by formula (5) or formula (6) The information is sent into the STC coding framework to obtain the steganographic index matrix of the carrier image of each frame to generate the dense image. The specific implementation of the embedded information can refer to FIG. 7 .

In step S214, multiple frames of steganographic images are obtained according to the steganographic index matrix of each frame of carrier image and the palette of each frame of carrier image to synthesize dynamic steganographic images. According to the delay time read in when the initial dynamic image is obtained, a dynamic image with hidden secret information can be obtained by combining and outputting the secret steganographic images of multiple frames as a dynamic image.

According to the dynamic image steganography method provided by the embodiment of the present application, each value in the index matrix is modified by obtaining a color index image including an index matrix and a color palette of each frame of the carrier image in the multi-frame carrier image from the dynamic image. After the modified index matrix is obtained, each frame carrier is obtained according to the pixel value of each channel of each frame carrier image obtained by the index matrix index palette and the modified pixel value of each channel of each frame carrier image obtained by modifying the index matrix index palette. The distortion cost matrix of the image, and then based on the distortion cost matrix of the carrier image of each frame, the steganographic information is embedded in the index matrix to obtain the steganographic index matrix of the carrier image of each frame, and finally the steganographic index matrix of the carrier image of each frame and the carrier image of each frame are obtained. The color palette of the image obtains multiple frames of steganographic images to synthesize dynamic steganographic images, so that steganography based on dynamic index images can be realized, which is more suitable for color images and is more concealed and difficult to detect; it can make steganography based on STC coding. The writing method is more suitable for hiding the information to be sent in a public dynamic carrier image for transmission, realizing the transmission of the carrier at the transceiver end, and improving the information embedding rate and security.

FIG. 3 shows a schematic diagram of the processing procedure of step S202 shown in FIG. 2 in an embodiment. As shown in FIG. 3 , in this embodiment of the present application, the foregoing step S202 may further include the following steps.

Step S2022, acquiring the initial index matrix and initial color palette of each frame of carrier image.

Step S2024: Reorder the initial palettes of the carrier images of each frame according to the sum of squares of the values of each channel to obtain the palette of the carrier images of each frame.

Step S2026: Obtain the index matrix of each frame of carrier image according to the initial index matrix of each frame of carrier image, the initial palette, and the palette. For each frame of carrier image, when it is used as the current frame image used to hide the secret information, the read-in initial palette can be reordered according to the sum of the squares of the channel values to generate a new palette, and a new palette corresponding to the new palette can be generated. New index matrix for palettes.

According to the palette reordering method provided by the embodiment of the present application, by reordering the initial palette according to the sum of the squares of the values of each channel, the complexity of modifying the carrier image is increased, so that it is possible to improve the concealment of the index image. Write stealth and detection resistance.

Fig. 4 is a flowchart of a method for obtaining a distortion cost according to an exemplary embodiment. The method shown in FIG. 4 can be applied to, for example, the server side of the above-mentioned system, and can also be applied to the terminal device of the above-mentioned system.

Referring to FIG. 4 , the method 40 provided by this embodiment of the present application may include the following steps.

In step S402, a color index image of the carrier image of the current frame is obtained, and the carrier image of the current frame is any frame after the carrier image of the first frame of the carrier images of the multiple frames.

In step S404, grayscale conversion is performed on the color index image of the carrier image of the current frame to obtain a grayscale image of the carrier image of the current frame.

In step S406, the color index image of the carrier image of the previous frame of the carrier image of the current frame is acquired.

In step S408, grayscale conversion is performed on the color index image of the steganographic image of the previous frame to obtain the grayscale image of the carrier image of the previous frame.

In some embodiments, the gray image converted from the color index image of the current k-th frame can be recorded as G _k =(G _ij ), and the gray image corresponding to the steganographic image in which secret information has been embedded in the previous frame is G _k-1 =(B _ij ).

In step S410, the difference between the grayscale image of the carrier image of the current frame and the grayscale image of the carrier image of the previous frame is squared to obtain the luminance variation of each pixel in the carrier image of the current frame.

In step S412, a luminance change threshold is obtained.

In step S414, when the luminance variation of a pixel in the current frame carrier image is greater than the luminance variation threshold, the sum of the squares of the difference between the total distortion cost value of the current frame carrier image and the pixel value of each channel of the pixel and the modified pixel value is calculated Multiply to obtain the color change amount of the pixel to obtain the distortion cost matrix of each frame of carrier image.

In step S4162, when the luminance variation of a pixel in the current frame carrier image is not greater than the luminance variation threshold, a distortion cost weight is obtained, and the distortion cost weight is a value greater than 1.

In step S4164, the total distortion cost value of the current frame carrier image is multiplied by the square sum of the difference between the pixel value of each channel of the pixel and the modified pixel value, and then multiplied by the distortion cost weight to obtain the color change amount of the pixel, to obtain the distortion cost matrix of each frame carrier image.

In some embodiments, the brightness change threshold can be recorded as ε, the distortion cost weight is δ, and δ>1, then equation (5) can be rewritten as:

In the formula, ((G _ij )-(B _ij )) ² is compared with the preset threshold ε, if it is greater than the threshold, it indicates that the area is a region with large changes, suitable for hiding information; if it is smaller than the threshold, then It shows that this area is a flat area, which is not suitable for steganography, so the distortion cost value needs to be multiplied by a weight δ greater than 1.

In some embodiments, for example, when the carrier dynamic image is an animated expression, the character line is the main component of the animated expression, and the pixel values of each point on the line are similar; at the same time, there is a large area of coloring in the image, and The pixel values in the same area are the same, so if you modify the shaded area, it is easy to find abnormalities in dense images. The above characteristics can be considered as a constraint on formula (6), the part of the contour (boundary) area of the image is calculated according to formula (6), and the distortion cost value is set to a preset distortion value in the non-contour area, and the preset The distortion value is a large threshold, that is, no information is embedded in this part, which can effectively improve the quality of dense images. For a specific implementation of the method for extracting image boundary information, reference may be made to FIG. 5 .

According to the method for obtaining the distortion cost provided by the embodiment of the present application, when calculating the distortion cost of each pixel, by considering whether the change in the brightness of the corresponding pixels between frames is suitable for hiding information, the method can be more suitable for steganography of dynamic images, and the improvement is improved. security of encrypted images.

Fig. 5 is a flowchart of an image boundary method according to an exemplary embodiment. The method shown in FIG. 5 can be applied to, for example, the server side of the above-mentioned system, and can also be applied to the terminal device of the above-mentioned system.

Referring to FIG. 5 , the method 50 provided by this embodiment of the present application may include the following steps.

In step S502, binarization processing is performed on the color index image of each frame of carrier image to obtain a binary image of each frame of carrier image.

In step S504, the boundary information of the binary image of each frame of carrier image is extracted, and the boundary information value of each pixel of each frame of carrier image is obtained.

In some embodiments, for example, C _k =(C _ij ) can be denoted as the boundary information extracted from the current frame, then when the pixel at the position (i,j) of the current frame is the boundary, denote C _ij =1, and 1 is true Boundary value; when the pixel at the position of the current frame (i, j) is not a boundary, it can be recorded as C _ij =0.

According to the method provided by the embodiment of the present application, by considering the boundary information when calculating the distortion cost of each pixel, steganography is performed at the outline of the image, which improves the visual effect of the dense animated expression and improves the security of steganography.

FIG. 6 is a frame diagram of an animation expression steganography method shown in FIGS. 2 to 5 . As shown in FIG. 6 , first decompose (S602) the animated expression 6002 into multiple frames of color index images 6004, and embed secret information for each frame of images according to the designed information embedding method (S604) to obtain multiple images with hidden secret information. In the image 6006, a plurality of frames are combined (S606) and output as an animation image to obtain an animation expression with secret information hidden.

FIG. 7 is a schematic diagram of a steganographic process of each frame of images shown in FIGS. 2 to 6 . As shown in FIG. 7 , for the image 7002 used to hide the secret information in the current frame, first reorder the read palette according to the sum of the squares of the RGB three-channel values to generate a new palette (S702), and generate a corresponding palette A new index matrix for the new palette (S704). Then, the current color index image is binarized to generate a binary image (S706), and then the boundary information of the binary image is extracted (S708), and the boundary information is used to define a distortion cost function. Then, the color index map 7002 of the current frame and the color index map 7004 of the previous frame in which secret information has been hidden are both converted into grayscale images (S7102, S7104), which are also used to define the distortion cost function. Finally, according to the extracted boundary information, the grayscale images of the current frame and the previous frame, and the new palette and index matrix of the current frame, define a distortion cost function, calculate the distortion cost function value of each pixel (S712), and The calculated distortion cost function value, index matrix and secret information 7006 are sent to the STC coding framework (S714), and the secret image 7008 can be obtained.

FIG. 8 is a set of example diagrams of experimental results of performing STC coding steganography on multiple animation expressions according to the dynamic image steganography method shown in FIG. 2 to FIG. 6 . As shown in Figure 8(a) to (i), it can be seen from the comparison between the original image and the corresponding secret images with steganographic 600-bit and 1100-bit secret information respectively, the visual effect of the image with the secret information hidden Good, the existence of information cannot be seen by the naked eye, and there is no obvious visual difference between dense images under different embedding rates, which shows that the experimental effect of this method is good.

FIG. 9 is a comparison of the two-dimensional image of the distortion cost value of the image calculated according to the dynamic image steganography method shown in FIG. 2 to FIG. 6 and the method of the prior art. In the prior art method, the pixel modification of each channel is not considered separately when calculating the distortion cost. As shown in Figure 9, (a) is the original carrier image, (b) is the image boundary information, (c) is the pixel+1 distortion cost value calculated by the method of the application, (d) is the pixel-calculated by the method of the application Distortion cost value of 1, (e) Distortion cost value of pixel+1 calculated by the prior art method, (f) Distortion cost value of pixel-1 calculated by the prior art method. As can be seen from Figure 9, the distribution of the distortion cost value calculated by the method of the present application is obviously different from the distribution of the distortion cost value calculated by the prior art method, the two-dimensional image of the distortion cost value of the method of the present application and the original image are extracted. The contour boundary information is similar, and the distortion cost calculated according to the prior art method is smaller in the large-area coloring area, and larger in other areas. It can be seen that the prior art method preferentially modifies the large-area coloring area when embedding information. According to the characteristics of animation expressions: the color information of the animation image is rich in the outline and the colors are similar, and the other large-area coloring areas are a single color, which is not suitable for modification. It can be seen that the distortion cost function proposed by the method of the present application fits well with the characteristics of animation images, and information is preferentially embedded in the contour area of the expression image.

The following table shows the comparative experimental data between the method of the present application and the method of the prior art, and the test errors of the two methods under the condition of 6 different embedding amounts are shown in the table. It can be seen that when the Subtractive Pixel Adjacency Matrix (SPAM) feature and embedded information are 600 bits (bit), the PE value of the distortion cost function proposed by the formula (6) of the present application is higher than that of the prior art. improved by 14.97%; the PE value increased by 9.09% in the spatial domain model (Spatial Rich Model, SRMQ1) feature and 600bit. When the SPAM feature and embedded information are 1100 bits, the distortion cost function proposed in the formula (6) of the present application is 12.85% higher than the PE value of the prior art method; the PE value of this method is increased by 4.86 under the SRMQ1 feature and 1100 bits. %.

Figures 10 and 11 plot the data in the above table, and show the comparison of the test errors between the method of the present application and the prior art under the SPAM and SRMQ1 features, respectively. It can be seen intuitively that the test errors of the two methods increase with the embedded At the same time, the PE value of the method proposed in the present application is much higher than that of the prior art regardless of the embedding rate.

It can be seen from the above experimental data that the performance of the method of the present application is obviously better than that of the prior art, indicating that the method of the present application has stronger anti-steganalysis ability.

Fig. 12 is a block diagram of a dynamic image steganography device according to an exemplary embodiment. The apparatus shown in FIG. 12 can be applied to, for example, the server side of the above-mentioned system, and can also be applied to the terminal device of the above-mentioned system.

Referring to FIG. 12 , the dynamic image steganography apparatus 120 provided by the embodiment of the present application may include an index image obtaining module 1202 , an index value modification module 1204 , a first pixel value obtaining module 1206 , a second pixel value obtaining module 1208 , and a distortion cost obtaining module 1210 , a steganographic index matrix obtaining module 1212 and a steganographic image obtaining module 1214 .

The index image obtaining module 1202 can be used to obtain a color index image of each frame of the carrier image in the multi-frame carrier image, and the multi-frame carrier image is obtained from a dynamic image, and the color index image includes an index matrix and a color palette.

The index value modification module 1204 may be configured to modify each value in the index matrix to obtain a modified index matrix.

The first pixel value obtaining module 1206 may be configured to index the palette according to the index matrix to obtain the pixel value of each channel of each frame of carrier image.

The second pixel value obtaining module 1208 may be configured to index the palette according to the modified index matrix to obtain the modified pixel value of each channel of each frame of carrier image.

The distortion cost obtaining module 1210 may be configured to obtain a distortion cost matrix of each frame of carrier image according to the pixel value of each channel of each frame of carrier image and the modified pixel value of each frame of carrier image.

The steganographic index matrix obtaining module 1212 can be configured to embed the information to be steganographic into the index matrix based on the distortion cost matrix of the carrier image of each frame, and obtain the steganographic index matrix of the carrier image of each frame.

The steganographic image obtaining module 1214 can be configured to obtain multiple frames of steganographic images according to the steganographic index matrix of each frame of carrier image and the palette of each frame of carrier image, so as to synthesize dynamic steganographic images.

Fig. 13 is a block diagram of a dynamic image steganography device according to an exemplary embodiment. The apparatus shown in FIG. 13 can be applied to, for example, the server side of the above-mentioned system, and can also be applied to the terminal device of the above-mentioned system.

13 , the dynamic image steganography device 130 provided by the embodiment of the present application may include an index image obtaining module 1302, a current carrier image obtaining module 13032, a previous frame carrier image obtaining module 13034, a grayscale conversion module 13036, and an index value modification module 1304, binarization processing module 13052, boundary extraction module 13054, true boundary value acquisition module 13056, preset distortion value acquisition module 13058, first pixel value acquisition module 1306, second pixel value acquisition module 1308, high-pass filter module 13092, A channel distortion cost calculation module 13094, a distortion cost acquisition module 1310, a steganographic index matrix acquisition module 1312, and a steganographic image acquisition module 1314, wherein the index image acquisition module 1302 may include an initial index image acquisition module 13022, a palette update module 13024 and the index matrix update module 13026, the distortion cost obtaining module 1310 may include a pixel difference module 13102, an image distortion cost calculation module 13104, a pixel change calculation module 13106, a distortion cost value calculation module 13108, a distortion cost matrix calculation module 13110, a brightness change amount A calculation module 13112 , a brightness change threshold obtaining module 13114 , and a distortion cost weight obtaining module 13116 .

The index image obtaining module 1302 can be used to obtain a color index image of each frame of the carrier image in the multi-frame carrier image, and the multi-frame carrier image is obtained from a dynamic image, and the color index image includes an index matrix and a color palette.

The initial index image obtaining module 13022 can be used to obtain the initial index matrix and initial color palette of each frame of carrier image.

The current carrier image obtaining module 13032 can be configured to acquire the color index image of the carrier image of the current frame, where the carrier image of the current frame is any frame after the carrier image of the first frame of the carrier images of the multiple frames.

The previous frame carrier image obtaining module 13034 may be configured to acquire the color index image of the previous frame carrier image of the current frame carrier image.

The grayscale conversion module 13036 can be used to perform grayscale conversion on the color index image of the carrier image of the current frame to obtain the grayscale image of the carrier image of the current frame; perform grayscale conversion on the color index image of the steganographic image of the previous frame to obtain the previous frame. Grayscale image of the frame vector image.

The palette updating module 13024 may be configured to reorder the initial palettes of the carrier images of each frame according to the sum of the squares of the values of each channel to obtain the palette of the carrier images of each frame.

The index matrix updating module 13026 may be configured to obtain the index matrix of each frame carrier image according to the initial index matrix, the initial palette, and the palette of each frame carrier image.

The index value modification module 1304 may be configured to modify each value in the index matrix to obtain a modified index matrix.

The binarization processing module 13052 can be used to perform binarization processing on the color index images of the carrier images of each frame to obtain the binary images of the carrier images of each frame.

The boundary extraction module 13054 can be used to extract the boundary information of the binary image of each frame of carrier image, and obtain the boundary information value of each pixel of each frame of carrier image.

The true boundary value acquisition module 13056 may be used to obtain the true boundary value.

The preset distortion value obtaining module 13058 can be used to obtain the preset distortion value.

The first pixel value obtaining module 1306 may be configured to index the palette according to the index matrix to obtain the pixel value of each channel of each frame of carrier image.

The second pixel value obtaining module 1308 may be configured to index the palette according to the modified index matrix to obtain the modified pixel value of each channel of each frame of carrier image.

The high-pass filtering module 13092 can be used to filter the pixels of each channel with a high-pass filter for each channel of the carrier image of each frame, and then obtain the absolute value of the filtering result.

The channel distortion cost calculation module 13094 can be configured to use a low-pass filter to smooth the absolute value of the filtering result to obtain the final residual, and then take the reciprocal to obtain the distortion cost value of each channel of each frame of carrier image.

The distortion cost obtaining module 1310 may be configured to obtain a distortion cost matrix of each frame of carrier image according to the pixel value of each channel of each frame of carrier image and the modified pixel value of each frame of carrier image.

The pixel difference module 13102 can be used to obtain the difference between the pixel value of each channel of the carrier image of each frame and the modified pixel value.

The image distortion cost calculation module 13104 may be configured to obtain a distortion cost matrix of each frame of carrier image according to the difference between the pixel value of each channel of each frame of carrier image and the modified pixel value and the distortion cost value of each channel of each frame of carrier image.

The pixel change calculation module 13106 can be used to obtain the sum of squares of the difference between the pixel value of each channel of the carrier image of each frame and the difference of the modified pixel value.

The distortion cost value calculation module 13108 may be configured to average the distortion cost values of each channel of each frame of carrier image to obtain the total distortion cost value of each frame of carrier image.

The distortion cost matrix calculation module 13110 can be configured to multiply the total distortion cost value of each frame of carrier image and the sum of squares of the difference between the pixel value of each channel and the modified pixel value to obtain the distortion cost matrix of each frame of carrier image.

The luminance variation calculation module 13112 can be used to square the difference between the grayscale image of the carrier image of the current frame and the grayscale image of the carrier image of the previous frame to obtain the luminance variation of each pixel in the carrier image of the current frame.

The brightness change threshold obtaining module 13114 may be used to obtain the brightness change threshold.

The distortion cost matrix calculation module 13110 can also be used to calculate the difference between the total distortion cost value of the current frame carrier image and the pixel value of each channel of the pixel and the modified pixel value when the luminance variation of a pixel in the current frame carrier image is greater than the luminance variation threshold. Multiply the sum of the squares of the differences to obtain the color change amount of the pixel to obtain the distortion cost matrix of each frame of the carrier image.

The distortion cost weight obtaining module 13116 can be used to obtain the distortion cost weight, and the distortion cost weight is a value greater than 1.

The distortion cost matrix calculation module 13110 can also be used to calculate the total distortion cost value of the current frame carrier image and the pixel value of each channel of the pixel and the modified pixel value when the luminance variation of a pixel in the current frame carrier image is not greater than the luminance variation threshold. Multiply the squared sum of the difference and then multiply it by the distortion cost weight to obtain the color change amount of the pixel to obtain the distortion cost matrix of each frame of carrier image.

The distortion cost matrix calculation module 13110 can also be used to obtain the distortion cost of the pixel according to the pixel value of each channel of the pixel and the modified pixel value when the boundary information value of the pixel is equal to the true boundary value for each pixel of each frame of the carrier image. , to obtain the distortion cost matrix of each frame carrier image.

The distortion cost matrix calculation module 13110 can also be used for each pixel of each frame of the carrier image, when the boundary information value of the pixel is not equal to the true boundary value, the distortion cost of the pixel is obtained as the preset distortion value, so as to obtain each frame of the carrier image. The distortion cost matrix of .

The steganographic index matrix obtaining module 1312 can be configured to embed the information to be steganographic into the index matrix based on the distortion cost matrix of the carrier image of each frame, and obtain the steganographic index matrix of the carrier image of each frame.

The steganographic image obtaining module 1314 can be configured to obtain multiple frames of steganographic images according to the steganographic index matrix of each frame of carrier image and the palette of each frame of carrier image, so as to synthesize dynamic steganographic images.

For the specific implementation of each module in the apparatus provided in the embodiment of the present application, reference may be made to the content in the foregoing method, and details are not repeated here.

FIG. 14 shows a schematic structural diagram of an electronic device in an embodiment of the present application. It should be noted that the device shown in FIG. 14 is only an example of a computer system, and should not impose any limitations on the functions and scope of use of the embodiments of the present application.

As shown in FIG. 14, the apparatus 1400 includes a central processing unit (CPU) 1401, which can be processed according to a program stored in a read only memory (ROM) 1402 or a program loaded into a random access memory (RAM) 1403 from a storage section 1408 Various appropriate actions and processes are performed. In the RAM 1403, various programs and data required for the operation of the device 1400 are also stored. The CPU 1401, the ROM 1402, and the RAM 1403 are connected to each other through a bus 1404. An input/output (I/O) interface 1405 is also connected to bus 1404 .

The following components are connected to the I/O interface 1405: an input section 1406 including a keyboard, a mouse, etc.; an output section 1407 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 1408 including a hard disk, etc. ; and a communication section 1409 including a network interface card such as a LAN card, a modem, and the like. The communication section 1409 performs communication processing via a network such as the Internet. Drivers 1414 are also connected to I/O interface 1405 as needed. A removable medium 1411, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is mounted on the drive 1414 as needed so that a computer program read therefrom is installed into the storage section 1408 as needed.

In particular, according to embodiments of the present application, the processes described above with reference to the flowcharts may be implemented as computer software programs. For example, embodiments of the present application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the method illustrated in the flowchart. In such an embodiment, the computer program may be downloaded and installed from the network via the communication portion 1409, and/or installed from the removable medium 1411. When the computer program is executed by the central processing unit (CPU) 1401, the above-described functions defined in the system of the present application are executed.

It should be noted that the computer-readable medium shown in this application may be a computer-readable signal medium or a computer-readable storage medium, or any combination of the above two. The computer readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus or device, or any combination of the above. More specific examples of computer readable storage media may include, but are not limited to, electrical connections with one or more wires, portable computer disks, hard disks, random access memory (RAM), read only memory (ROM), erasable Programmable read only memory (EPROM or flash memory), fiber optics, portable compact disk read only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing. In this application, a computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In this application, however, a computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code therein. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the foregoing. A computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium that can transmit, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device . Program code embodied on a computer readable medium may be transmitted using any suitable medium including, but not limited to, wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present application. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code that contains one or more logical functions for implementing the specified functions executable instructions. It should also be noted that, in some alternative implementations, the functions noted in the blocks may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It is also noted that each block of the block diagrams or flowchart illustrations, and combinations of blocks in the block diagrams or flowchart illustrations, can be implemented in special purpose hardware-based systems that perform the specified functions or operations, or can be implemented using A combination of dedicated hardware and computer instructions is implemented.

The modules involved in the embodiments of the present application may be implemented in a software manner, and may also be implemented in a hardware manner. The described module can also be set in the processor, for example, it can be described as: a processor includes an index image obtaining module, an index value modification module, a first pixel value obtaining module, a second pixel value obtaining module, and a distortion cost obtaining module. module, steganographic index matrix obtaining module and steganographic image obtaining module. Among them, the names of these modules do not constitute a limitation of the module itself under certain circumstances. For example, the index image acquisition module can also be described as "a module for obtaining color index images of multiple frames of carrier images from dynamic carrier images". .

As another aspect, the present application also provides a computer-readable medium. The computer-readable medium may be included in the device described in the above embodiments, or may exist alone without being assembled into the device. The above-mentioned computer-readable medium carries one or more programs, and when the above-mentioned one or more programs are executed by a device, the device includes:

Obtain the color index image of each frame of the carrier image in the multi-frame carrier image, the multi-frame carrier image is obtained from the dynamic image, and the color index image includes an index matrix and a palette; modify each value in the index matrix to obtain a modified index matrix ; According to the index matrix index palette, obtain the pixel value of each channel of each frame carrier image; According to the modified index matrix index palette, obtain the modified pixel value of each channel of each frame carrier image; According to each frame carrier image The pixel value of the channel and the modified pixel value of each channel of the carrier image of each frame obtain the distortion cost matrix of the carrier image of each frame; based on the distortion cost matrix of the carrier image of each frame, the information to be steganographic is embedded in the index matrix to obtain the carrier image of each frame. Steganographic index matrix; according to the steganographic index matrix of each frame of carrier image and the palette of each frame of carrier image, multiple frames of steganographic images are obtained to synthesize dynamic steganographic images.

Exemplary embodiments of the present application have been specifically shown and described above. It should be understood that this application is not limited to the details of construction, arrangements, or implementations described herein; on the contrary, this application is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

A dynamic image steganography method, comprising:

obtaining a color indexed image of each frame of carrier image in a multi-frame carrier image obtained from the dynamic image, the color indexed image comprising an index matrix and a palette;

Modify each value in the index matrix to obtain a modified index matrix;

Index the palette according to the index matrix to obtain the pixel value of each channel of each frame of carrier image;

Index the palette according to the modified index matrix to obtain the modified pixel value of each channel of each frame of carrier image;

Obtain the distortion cost matrix of each frame of carrier image according to the pixel value of each channel of each frame of carrier image and the modified pixel value of each channel of each frame of carrier image;

Embedding the information to be steganographic into the index matrix based on the distortion cost matrix of the carrier image of each frame, to obtain the steganographic index matrix of the carrier image of each frame;

Multiple frames of steganographic images are obtained according to the steganographic index matrix of the carrier images of each frame and the palette of the carrier images of each frame to synthesize dynamic steganographic images.
The method of claim 1, further comprising:

For each channel of each frame of the carrier image, a high-pass filter is used to filter the pixels of each channel, and then the absolute value of the filtering result is obtained;

Use a low-pass filter to smooth the absolute value of the filtering result to obtain the final residual, and then take the reciprocal to obtain the distortion cost value of each channel of each frame of the carrier image;

The obtaining of the distortion cost matrix of each frame of carrier image according to the pixel value of each channel of each frame of carrier image and the modified pixel value of each channel of each frame of carrier image includes:

Obtain the difference between the pixel value of each channel of the carrier image of each frame and the modified pixel value;

The distortion cost matrix of each frame of carrier image is obtained according to the difference between the pixel value of each frame of carrier image and the modified pixel value and the distortion cost value of each channel of each frame of carrier image.
The method according to claim 2, wherein the obtaining a color index image of each frame of carrier images in the multi-frame carrier images comprises:

Obtain the initial index matrix and initial palette of each frame of carrier image;

reordering the initial palette of the carrier images of each frame according to the sum of the squares of the channel values to obtain the palette of the carrier images of each frame;

Obtain the index matrix of each frame carrier image according to the initial index matrix of each frame carrier image, the initial palette, and the palette;

Described according to the difference between the pixel value of each channel of the frame carrier image and the modified pixel value and the distortion cost value of each channel of the frame carrier image to obtain the distortion cost matrix of each frame carrier image includes:

Obtain the square sum of the difference between the pixel value of each channel of the carrier image of each frame and the modified pixel value;

The total distortion cost value of each frame of carrier image is obtained by averaging the distortion cost value of each channel of each frame of carrier image;

Multiplying the total distortion cost value of each frame of carrier image and the sum of squares of the difference between the pixel value of each channel and the modified pixel value to obtain the distortion cost matrix of each frame of carrier image.
The method of claim 3, further comprising:

Obtaining the color index image of the current frame carrier image, the current frame carrier image is any frame after the first frame carrier image in the multi-frame carrier images;

Perform grayscale conversion on the color index image of the current frame carrier image to obtain the grayscale image of the current frame carrier image;

obtaining the color index image of the previous frame carrier image of the current frame carrier image;

Perform grayscale conversion on the color index image of the steganographic image of the previous frame to obtain the grayscale image of the carrier image of the previous frame;

Multiplying the total distortion cost value of each frame of carrier image by the sum of squares of the difference between the pixel value of each channel and the modified pixel value to obtain the distortion cost matrix of each frame of carrier image includes:

Square the grayscale image of the carrier image of the current frame and the grayscale image of the carrier image of the previous frame after making a difference, obtain the luminance variation of each pixel in the carrier image of the current frame;

Get the brightness change threshold;

When the luminance change amount of a pixel in the current frame carrier image is greater than the luminance change threshold, the square of the difference between the total distortion cost value of the current frame carrier image and the pixel value of each channel of the pixel and the modified pixel value is calculated and multiplied to obtain the color change amount of the pixel, so as to obtain the distortion cost matrix of the carrier image of each frame.
The method according to claim 3, wherein the total distortion cost value of the carrier image of each frame is multiplied by the square sum of the difference between the pixel value of each channel and the modified pixel value to obtain the frame The distortion cost matrix of the carrier image includes:

Get the brightness change threshold;

obtaining a distortion cost weight, the distortion cost weight being a value greater than 1;

When the amount of luminance change of a pixel in the carrier image of the current frame is not greater than the luminance change threshold, calculate the difference between the total distortion cost value of the carrier image of the current frame and the difference between the pixel value of each channel of the pixel and the modified pixel value The squared sum is multiplied and then multiplied by the distortion cost weight to obtain the color change amount of the pixel, so as to obtain the distortion cost matrix of the carrier image of each frame.
The method according to any one of claims 1 to 5, further comprising:

Perform binarization processing on the color index image of each frame of carrier image to obtain a binary image of each frame of carrier image;

Extracting the boundary information of the binary image of each frame carrier image, and obtaining the boundary information value of each pixel of each frame carrier image;

Get the true boundary value;

The obtaining of the distortion cost matrix of each frame of carrier image according to the pixel value of each channel of each frame of carrier image and the modified pixel value of each channel of each frame of carrier image includes:

For each pixel of the carrier image of each frame, when the boundary information value of the pixel is equal to the true boundary value, the distortion cost of the pixel is obtained according to the pixel value of each channel of the pixel and the modified pixel value, so as to obtain the frame. Distortion cost matrix for the carrier image.
The method of claim 6, further comprising:

Get the preset distortion value;

The obtaining the distortion cost matrix of each frame of carrier image according to the pixel value of each channel of each frame of carrier image and the modified pixel value of each channel of each frame of carrier image further includes:

For each pixel of the carrier image of each frame, when the boundary information value of the pixel is not equal to the true boundary value, the distortion cost of the pixel obtained is the preset distortion value, so as to obtain the distortion cost of the carrier image of each frame matrix.
A dynamic image steganography device, comprising:

an index image obtaining module, configured to obtain a color index image of each frame of carrier images in the multi-frame carrier images, the multi-frame carrier images are obtained from the dynamic image, and the color index images include an index matrix and a palette;

an index value modification module for modifying each value in the index matrix to obtain a modified index matrix;

a first pixel value obtaining module, configured to index the palette according to the index matrix to obtain the pixel value of each channel of each frame of carrier image;

A second pixel value obtaining module, configured to index the palette according to the modified index matrix, to obtain the modified pixel value of each channel of each frame of carrier image;

a distortion cost obtaining module, configured to obtain a distortion cost matrix of each frame of the carrier image according to the pixel value of each channel of the each frame of carrier image and the modified pixel value of each channel of the each frame of carrier image;

a steganographic index matrix obtaining module, used for embedding the information to be steganographic into the index matrix based on the distortion cost matrix of the carrier images of each frame, to obtain the steganographic index matrix of the carrier images of each frame;

The steganographic image obtaining module is configured to obtain multiple frames of steganographic images according to the steganographic index matrix of the carrier images of each frame and the palette of the carrier images of each frame, so as to synthesize dynamic steganographic images.
A device, comprising: a memory, a processor, and executable instructions stored in the memory and executable in the processor, characterized in that, when the processor executes the executable instructions, the implementation as claimed in the claims The method of any one of 1 to 7.
A computer-readable storage medium on which computer-executable instructions are stored, characterized in that, when the executable instructions are executed by a processor, the method according to any one of claims 1 to 7 is implemented.