CN114742690A - Multi-view color image watermark processing method and system based on hexadecimal moments - Google Patents

Abstract

The invention provides a multi-view color image watermarking processing method and system based on a sixteen-element moment, which are used for acquiring an original multi-view color image and an original watermark image to be processed, processing the original multi-view color image to obtain an accurate sixteen-element moment value, embedding the original watermark image into the sixteen-element moment value, reconstructing to obtain a watermark-containing sixteen-element moment image, and performing difference combination processing on the original multi-view color image, the sixteen-element moment value and the watermark-containing sixteen-element moment image to obtain the watermark-containing multi-view color image; the method has strong stability and image reconstruction performance based on the sixteen element moment, effectively realizes the embedding and extraction of the multi-view color image watermark, and has good robustness and imperceptibility in protecting the copyright of the multi-view color image.

Description

Multi-view color image watermark processing method and system based on hexadecimal moments

technical field

The invention belongs to the technical field of digital watermarking, in particular to a multi-view color image watermarking method based on hexadecimal moments.

Background technique

The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

With the continuous development of the Internet, the opening and sharing of data is becoming more and more popular, which also makes the problem of infringement more and more serious. How to ensure the safety of digital resources in storage and dissemination has become a widespread concern of the society. For copyright protection of digital images, encryption and signature technologies have been widely used, but neither of these two technologies solves the problem of illegal copying, tampering and re-distribution of decrypted images. The birth of digital watermarking has brought about a turning point in the copyright protection of images, and it has quickly become a research hotspot in the field of image copyright protection.

At present, the research on digital image watermarking has developed from grayscale images to color images. In recent years, stereoscopic image watermarking technology has also developed rapidly. However, there is still no mature solution for the research of multi-view color image watermarking technology. Multi-view color images are images captured by a single camera moving or multiple cameras arranged at a certain position according to parallax requirements to form a camera array, and are widely used in scene reconstruction and depth estimation. The research in the field of multi-view color image is very extensive, but there is no effective copyright protection strategy.

SUMMARY OF THE INVENTION

In order to overcome the above-mentioned deficiencies of the prior art, the present invention provides a multi-view color image watermark processing method and system based on hexadecimal moments, and applies the hexadecimal moment theory to the embedding and extraction process of multi-view color image watermarks, Using the imaginary part of the hexadecimal to process all color components of all viewing angles of a multi-view color image at the same time, while ensuring the correlation between the components, has good robustness and imperceptibility in protecting the copyright of multi-view color images.

To achieve the above object, one or more embodiments of the present invention provide the following technical solutions:

A first aspect of the present invention provides a multi-view color image watermark processing method based on hexadecimal moments;

The multi-view color image watermark processing method based on hexadecimal moments includes the following steps:

Obtain the original multi-view color image and the original watermark image to be processed;

Process the original multi-view color image to obtain the precise hexadecimal moment value;

Embed the original watermark image into the hexadecimal moment value, and reconstruct the watermarked hexadecimal moment image;

The original multi-perspective color image, the hexadecimal moment value and the watermarked hexadecimal moment image are combined with the difference value to obtain the watermarked multi-perspective color image.

Further, the method to obtain the exact hexadecimal moment value is:

Calculate the hexadecimal moment value of the original multi-view color image;

Eliminate inaccurate hexadecimal moment values to obtain accurate hexadecimal moment values.

Further, the key is used to randomly select the hexadecimal moment value from the exact hexadecimal moment value to construct the magnitude sequence, and the watermark image is embedded in the magnitude sequence by using the quantization method.

Further, the difference value merging process is to make a difference between the original multi-view color image and the hexadecimal moment value to obtain a difference value image, and combine the difference value image and the watermark hexadecion moment moment image to obtain: Watermarked multi-view color image.

Further, the hexadecimal moments are constructed based on hexadecimal theory and circular harmonic-Fourier moments.

Further, it also includes: extracting the watermark image from the watermark multi-view color image, and the specific extraction process is:

Preprocessing the watermarked multi-perspective color image into a square multi-perspective color image;

Calculate the hexadecimal moment value of the multi-view color image;

Extract the watermarked image from a sequence of magnitudes constructed from hexadecimal moment-of-moment values.

Further, the positive bit rate is used to measure the similarity between the original watermark image and the extracted watermark image to verify the copyright attribution of the image.

A second aspect of the present invention provides a multi-view color image watermark processing system based on hexadecimal moments.

A multi-view color image watermarking system based on hexadecimal moments, including:

a data acquisition module, configured to: acquire multi-view color images and watermark images to be processed;

The hexadecimal moment processing module is configured to: process the multi-view color image to obtain an accurate hexadecimal moment value;

The watermark embedding module is configured to: embed the watermark image in the hexadecimal moment value, and reconstruct the watermark hexadecimal moment image;

The difference merging module is configured to: perform difference merging processing on the multi-view color image, the hexadecimal moment value and the watermarked hexadecimal moment image to obtain a watermarked multi-view color image.

A third aspect of the present invention provides a computer-readable storage medium on which a program is stored, and when the program is executed by a processor, implements the multi-view color image watermarking method based on hexadecimal moments as described in the first aspect of the present invention steps in .

A fourth aspect of the present invention provides an electronic device, including a memory, a processor, and a program stored in the memory and executable on the processor, when the processor executes the program, the processor implements the system based on the first aspect of the present invention. Steps in a multi-view color image watermarking method of hexadecimal moments.

One or more of the above technical solutions have the following beneficial effects:

The invention applies the hexadecimal moment theory to the process of embedding and extracting multi-view color image watermarks. The hexadecimal moment has strong stability and image reconstruction performance, and can extract high-quality image features; the watermark information is embedded It has good robustness and imperceptibility to the hexadecimal moments of multi-view color images. When it is necessary to verify the copyright ownership of the multi-view color image, the watermark information is extracted by calculating the hexadecimal moment of the multi-view color image, so as to realize the copyright protection of the multi-view color image.

Description of drawings

The accompanying drawings forming a part of the present invention are used to provide further understanding of the present invention, and the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute an improper limitation of the present invention.

FIG. 1 is a flow chart of the method of the first embodiment.

FIG. 2 is a system structure diagram of the second embodiment.

Detailed ways

It should be noted that the following detailed description is exemplary and intended to provide further explanation of the invention. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It should be noted that the terminology used herein is for the purpose of describing specific embodiments only, and is not intended to limit the exemplary embodiments according to the present invention.

Embodiments of the invention and features of the embodiments may be combined with each other without conflict.

Terminology Explanation:

Radial harmonic Fourier moments (RHFMs).

Sedenion radial harmonic Fourier moments (SRHFMs).

When calculating the radial harmonic Fourier moments (RHFMs), it is necessary to convert the image defined in the rectangular coordinate system into the polar coordinate form. For an image f(r, θ) converted to polar form, its RHFMs are defined as follows:

where P _nm is the RHFMs, n(n∈N) is the order, m(m∈Z) is the repetition degree, exp(-jmθ) is the conjugate of the angular Fourier factor exp(jmθ), _Rn (r ) is the radial basis function:

R _n (r) is orthogonal in the range of 0≤r≤1, and its orthogonality relationship can be expressed as:

where _δno is the Kronecker function.

The basis functions of RHFMs are defined as:

B _nm (r,θ)=R _n (r)exp(jmθ) (4)

From the property of the angular Fourier factor exp(jmθ) conjugation and the orthogonality of the radial basis function, it can be deduced that the basis function B _nm (r, θ) is orthogonal in the unit circle, and its orthogonality The relationship can be expressed as:

为B_ol(r,θ)的共轭，0≤r≤1，0≤θ≤2π，2π为归一化因子。in

is the conjugate of B _ol (r, θ), 0≤r≤1, 0≤θ≤2π, and 2π is the normalization factor.

Since the basis functions of RHFMs are orthogonal, the original image f(r, θ) can be reconstructed using RHFMs, and the image reconstruction function of f(r, θ) can be expressed as:

Complex numbers can be extended to sixteen dimensions and are known as hexadecions. A hexadecimal consists of one real part and fifteen imaginary parts:

where x ₀ , x ₁ , ..., x ₁₅ are real parts, and e ₁ , e ₂ , ..., e ₁₅ are imaginary units.

A multi-view color image f ^S containing 5 viewing angles can be represented as a set of pure hexadecimal numbers, and the specific representation method is as follows:

Among them, f ^S (r, θ) is the polar coordinate form of f ^S , f _ri (r, θ), f _gi (r, θ), f _bi (r, θ) represent the multi-view color image f ^S (r , θ) of the red, green and blue components of the ith viewing angle.

Sedenion radialharmonic Fourier moments (SRHFMs) can be constructed based on the theory of hexadecons and RHFMs, because the multiplication of hexadecons does not satisfy the commutative law, and f ^S (r, θ) and exp(-μmθ) are both hexadecimals, so there are two ways to define SRHFMs:

where R _n (r) is the radial basis function of RHFMs and μ is a unit pure hexadecimal, which can be expressed as:

The right SRHFMs and left SRHFMs of the same set of images f ^S (r, θ) can be derived from each other, and their relationship can be expressed as:

是

的共轭。因为f^S(r,θ)是纯十六元数矩阵，则

所以：in,

Yes

the conjugate. Since f ^S (r, θ) is a pure hexadecion matrix, then

so:

和

重构图像的公式可分别表示为：use

and

The formulas for reconstructing the image can be expressed as:

Example 1

The present embodiment discloses a multi-view color image watermark processing method based on hexadecimal moments;

As shown in Figure 1, the multi-view color image watermark processing method based on hexadecimal moments includes:

S1: Obtain the original multi-view color image and the original watermark image to be processed;

Suppose I ^S ={f ^S (p,q),1≤p,q≤N} represents the original multi-view color image, and W={l(i,j),1≤i≤P,1≤j≤ Q} represents the original watermarked image.

S2: Process the original multi-view color image to obtain an accurate hexadecimal moment value;

The method to get the exact hexadecimal moment value is:

Calculate the hexadecimal moment value of the original multi-view color image;

Eliminate the hexadecimal moment values located at the four corners of the edge to obtain accurate hexadecimal moment values.

S2-1: SRHFMs Calculation

Calculate the ^SRHFMs whose maximum moment order of the original multi-view color image IS is N _max , and obtain (N _max +1)(2N _max +1) moment values.

S2-2: Precise SRHFMs Selection

To enhance the robustness of the scheme, precise SRHFMs are chosen for watermark embedding. For the image orthogonal moment, it has rotational invariance in theory, and the SRHFMs with the repetition degree m=4i, i∈Z are inconsistent with the theoretical value, which is easy to cause errors. Therefore, the SRHFMs with m=4i, i∈Z are excluded, and the accurate The set of SRHFMs is S ₁ ={SP _nm ,m≠4i,i∈Z}.

S3: Embed the original watermark image into the hexadecimal moment value, and reconstruct the watermarked hexadecimal moment image;

Use the key K ₁ to randomly select P×Q SRHFMs from the set S ₁ to construct the magnitude sequence, and then use the quantization method to embed the watermark image into the magnitude sequence A=(A ₁ ,A ₂ ,...,A _P×Q ), The quantification method is as follows:

Among them, _k =1,2,...,P×Q,λk=round( _A′k /Δ), _Ak and _A′k are the initial amplitude of the selected SRHFMs and the amplitude after embedding the watermark, mod( x, y) is the remainder function, round(x) is the rounding function, Δ is the quantization step size, and w(k) is the one-dimensional watermark information.

After the watermark is embedded in the SRHFMs, it is necessary to modify the SRHFMs around the symmetric position where m=0 is repeated, so that the real part of the moment value of the SRHFMs embedded in the watermark is still symmetrical about m=0.

S4: performing difference merging processing on the original multi-view color image, the hexadecimal moment value and the watermarked hexadecimal moment image to obtain a watermarked multi-view color image;

作差，得到差值图像，将差值图像和含水印SRHFMs重构的图像

进行合并，得到含水印多视角彩色图像

计算过程可表示为：The difference merging process is an image reconstructed from the original multi-view color image ^IS and the accurate SRHFMs

Make a difference to get a difference image, and the image reconstructed from the difference image and the watermarked SRHFMs

Merge to get watermarked multi-view color image

The calculation process can be expressed as:

When the multi-view color image is attacked, the watermark image is extracted from the watermarked multi-view color image to determine the copyright attribution. The specific extraction process is as follows:

(1) Image preprocessing

Since moment calculation can only be applied to square images, if each view angle of the multi-view color image ^IS* is a rectangular image of size M×N, preprocessing is required to convert the image into a uniform size of (M+N )/2×(M+N)/2 square multi-view color image.

(2) Calculation of SRHFMs

Calculate the SRHFMs of which the maximum moment order of the watermarked multi-view color image IS ^* is N _max , and obtain (N _max +1)(2N _max +1) moment values.

(3) Watermark Image Extraction

使用密钥K₁从集合

中随机选择P×Q个SRHFMs构建幅值序列，然后从幅值序列中提取水印信息

提取方法如下：The set of precise SRHFMs is

Use key _K1 from the collection

Randomly select P×Q SRHFMs to construct the amplitude sequence, and then extract the watermark information from the amplitude sequence

The extraction method is as follows:

floor(x)是向下取整函数。W^*＝{w^*(k),0≤k≤P×Q}为提取的水印信息。in,

floor(x) is the round down function. W ^* ={w ^* (k), 0≤k≤P×Q} is the extracted watermark information.

Convert W ^* into a two-dimensional image W′ of size P×Q, that is, the extracted watermark image.

(4) Watermark image verification

The bit correct ratio (BCR) is used to measure the consistency of the watermarked image W' with the original watermarked image W, and to verify the copyright of the image. The formula for calculating BCR is

where C represents the same number of pixels as W′ and W, and P×Q is the size of the watermarked image. The value of BCR is between 0 and 1. The larger the value of BCR, the higher the similarity between W' and W, and the better the robustness of the algorithm.

Embodiment 2

This embodiment discloses a multi-view color image watermark processing system based on hexadecimal moments;

As shown in Figure 2, the multi-view color image watermark processing system based on hexadecimal moments includes a data acquisition module, a hexadecimal moment processing module, a watermark embedding module and a difference merging module;

a data acquisition module, configured to: acquire multi-view color images and watermark images to be processed;

The hexadecimal moment processing module is configured to: process the multi-view color image to obtain an accurate hexadecimal moment value;

The watermark embedding module is configured to: embed the watermark image in the hexadecimal moment value, and reconstruct the watermark hexadecimal moment image;

The difference merging module is configured to: perform difference merging processing on the multi-view color image, the hexadecimal moment value and the watermarked hexadecimal moment image to obtain a watermarked multi-view color image.

Embodiment 3

The purpose of this embodiment is to provide a computer-readable storage medium.

A computer-readable storage medium on which a computer program is stored, and when the program is executed by a processor, implements the steps in the method for processing multi-view color image watermarking based on hexadecimal moments as described in Embodiment 1 of the present disclosure.

Embodiment 4

The purpose of this embodiment is to provide an electronic device.

An electronic device, including a memory, a processor, and a program stored in the memory and running on the processor, when the processor executes the program, the multiplication based on hexadecimal moments as described in Embodiment 1 of the present disclosure is implemented. Steps in a method for watermarking a perspective color image.

The steps involved in the apparatuses of the second, third, and fourth embodiments above correspond to the method embodiment 1, and the specific implementation can refer to the relevant description part of the embodiment 1. The term "computer-readable storage medium" should be understood to include a single medium or multiple media including one or more sets of instructions; it should also be understood to include any medium capable of storing, encoding or carrying for use by a processor The executed instruction set causes the processor to perform any of the methods of the present invention.

Those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general-purpose computer device, or alternatively, they can be implemented by a program code executable by the computing device, so that they can be stored in a storage device. The device is executed by a computing device, or they are separately fabricated into individual integrated circuit modules, or multiple modules or steps in them are fabricated into a single integrated circuit module for implementation. The present invention is not limited to any specific combination of hardware and software.

Although the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, they do not limit the scope of protection of the present invention. Those skilled in the art should understand that on the basis of the technical solutions of the present invention, those skilled in the art do not need to pay creative work. Various modifications or deformations that can be made are still within the protection scope of the present invention.

Claims (10)

1. a multi-view color image watermarking method based on hexadecimal moments, is characterized in that, comprises the following steps: Obtain the original multi-view color image and the original watermark image to be processed; Process the original multi-view color image to obtain the precise hexadecimal moment value; Embed the original watermark image into the hexadecimal moment value, and reconstruct the watermarked hexadecimal moment image; The original multi-perspective color image, the hexadecimal moment value and the watermarked hexadecimal moment image are combined with the difference value to obtain the watermarked multi-perspective color image. 2. the multi-view color image watermarking method based on hexadecimal moment as claimed in claim 1, is characterized in that, the method that obtains accurate hexadecimal moment value is: Calculate the hexadecimal moment value of the original multi-view color image; Eliminate inaccurate hexadecimal moment values to obtain accurate hexadecimal moment values. 3. The multi-view color image watermarking method based on hexadecimal moments as claimed in claim 1, characterized in that, using a key to randomly select hexadecimal moments from precise hexadecimal moment values value to construct a sequence of magnitudes, and the watermark image is embedded in the sequence of magnitudes using a quantization method. 4. The multi-view color image watermarking method based on hexadecimal moments as claimed in claim 1, characterized in that, the difference merging process is to combine the original multi-view color image and the hexadecimal moment values. Make a difference to obtain a difference image, and combine the difference image and the watermarked hexadecimal moment image to obtain a watermarked multi-view color image. 5. The multi-view color image watermarking method based on hexadecimal moments as claimed in claim 1, characterized in that, the hexadecimal moments are based on hexadecimal theory and circular harmonic-Fourier moments The constructed hexadecimal moment. 6. The multi-view color image watermark processing method based on hexadecimal moments as claimed in claim 1, is characterized in that, also comprises: extracting watermark image from watermark multi-view color image, concrete extraction process is: Preprocessing the watermarked multi-perspective color image into a square multi-perspective color image; Calculate the hexadecimal moment value of the multi-view color image; Extract the watermarked image from a sequence of magnitudes constructed from hexadecimal moment-of-moment values. 7. the multi-view color image watermarking method based on hexadecimal moment as claimed in claim 6, it is characterized in that, utilize positive code rate to measure the similarity of original watermark image and the watermark image of extraction, verify the copyright attribution of image . 8. The multi-view color image watermarking processing system based on hexadecimal moments, is characterized in that: comprising a data acquisition module, a hexadecimal moment processing module, a watermark embedding module and a difference merging module; a data acquisition module, configured to: acquire multi-view color images and watermark images to be processed; The hexadecimal moment processing module is configured to: process the multi-view color image to obtain an accurate hexadecimal moment value; The watermark embedding module is configured to: embed the watermark image in the hexadecimal moment value, and reconstruct the watermark hexadecimal moment image; The difference merging module is configured to: perform difference merging on the multi-view color image, the hexadecimal moment value and the watermarked hexadecimal moment image to obtain a watermarked multi-view color image. 9. A computer-readable storage medium having a program stored thereon, characterized in that, when the program is executed by a processor, the multi-view color image watermarking based on hexadecimal moments as claimed in any one of claims 1-7 is realized steps in the processing method. 10. An electronic device, comprising a memory, a processor and a program stored on the memory and running on the processor, wherein the processor implements the program described in any one of claims 1-7 when the processor executes the program The steps in a multi-view color image watermarking method based on hexadecimal moments.

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