CN110517182A - A kind of medical image zero watermarking embedding grammar based on NSCT combined transformation - Google Patents
A kind of medical image zero watermarking embedding grammar based on NSCT combined transformation Download PDFInfo
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- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T1/00—General purpose image data processing
- G06T1/0021—Image watermarking
- G06T1/005—Robust watermarking, e.g. average attack or collusion attack resistant
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- G06T2201/00—General purpose image data processing
- G06T2201/005—Image watermarking
- G06T2201/0052—Embedding of the watermark in the frequency domain
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- G06T2201/0065—Extraction of an embedded watermark; Reliable detection
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Abstract
This application discloses a kind of medical image zero watermarking embedding grammar, device, equipment and readable storage medium storing program for executing based on NSCT combined transformation, mixing transformation and Arnold conversion of the program based on NSCT, RDWT, DCT are realized, in watermark telescopiny, first, more robust medical image features vector is extracted, in conjunction with NSCT, RDWT, DCT to resist geometric attack.Secondly, enhancing the safety of watermark information using Arnold conversion encrypted watermark.Finally, realizing that watermark is embedded in using zero watermarking technology, the integrality, watermark capacity and stealth of medical image ensure that, avoid traditional watermark embedding technique to defect caused by artwork data modification, ensure that the quality of medical image.Therefore, even if patient information is attacked by intentionally or unintentionally, as long as unauthorized user does not know key, medical image and watermark just can not be cracked out, so that the personal information of patient is really protected.
Description
Technical field
This application involves field of computer technology, in particular to a kind of medical image zero watermarking based on NSCT combined transformation
Embedding grammar, device, equipment and readable storage medium storing program for executing.
Background technique
In field of biomedicine, a large amount of numerical data, including ultrasonic wave, X-ray photograph, CT and MRI can be all generated daily
Deng.And most of these data are all image storage and telecommunication to be carried out using PACS system, but transmit in cloud environment
It is easily stolen or distort with storing, so that researcher expands deeply the confidentiality, integrality and authenticity of medical image
Research.Meanwhile medical image contains a large amount of important informations of patient, when being stored and transmitted in the internet, faces
Security threat.Therefore, there is an urgent need to the medical images to patient to take safeguard measure.
In order to make to need to encrypt these data, and wish in remote access process not leak data privacy
Ciphertext domain completes data analysis.It can prevent unauthorized user from visiting relevant information using suitable Information hiding means
It asks, the current technology and methods there are many for conservation medicine image, such as digital watermarking, image latent writing art, cryptography etc., this
In a little technologies, digital watermark technology is one of most popular and widely used method, can be used for copyright, is protected, content authentication, is closed
Method ownership and communication security etc..
For digital figure watermark, we usually require to have good robustness geometry and conventional attack.In biology
The medical imaging data of medical domain, patient has the extremely stringent specification of quality, and storage or transmission is not allowed to lead to any view
Feel mass change.In addition, the extraction and insertion of watermark should be it is quick and real-time, so that it can be applied to tele-medicine.
There are also distorting etc. to threaten, need to consider to store that data in cloud and by the safety problem of the Internet transmission, together
When ensure the specific characteristic of medical image.Therefore, the digital watermarking of medical image is particularly important.
Currently, the diagnostic message of patient can be hidden in medical image according to the particular disease states of patient, to protect
The privacy of patient is protected from stolen.Such as in medical image using personal information as digital watermark embedding in medical image,
It can preferably solve the problems, such as the Information hiding of patient.Conventional method is that the watermark after scramble is directly embedded into original image
In, it does so and can protect watermark information, but still cannot eliminate the carrier information when medical image is by unauthorized access
The security risk of leakage.
As it can be seen that how to avoid the leakage of medical image and watermark information, and robustness is promoted, is urgently this field skill
Art personnel solve the problems, such as.
Summary of the invention
The purpose of the application be to provide a kind of medical image zero watermarking embedding grammar based on NSCT combined transformation, device,
Equipment and readable storage medium storing program for executing not can avoid medical image and watermark information to solve traditional watermark insertion scheme
Leakage, and the problem that robustness is poor.
Concrete scheme is as follows:
In a first aspect, this application provides a kind of medical image zero watermarking embedding grammar based on NSCT combined transformation, packet
It includes:
The binary bitmap for obtaining original medical image and being generated according to patient information；
NSCT transformation, RDWT transformation and dct transform are carried out respectively to the pixel grey scale value matrix of the original medical image,
Obtain coefficient matrix；The two-value symbol for extracting the middle low frequency coefficient of preset quantity in the coefficient matrix, using as described original
The eigenvectors matrix of medical image；
Arnold conversion, the watermark information square encrypted are carried out to the pixel grey scale value matrix of the binary bitmap
Battle array；
XOR operation is carried out to the watermark information matrix of described eigenvector matrix and the encryption, obtains logical key square
Battle array, to realize the insertion of zero watermarking.
Preferably, XOR operation is carried out in the watermark information matrix to described eigenvector matrix and the encryption,
After obtaining logical key matrix, further includes:
It is extracted and is requested according to zero watermarking, determine the medical image to be measured for having zero watermarking；
NSCT transformation, RDWT transformation and dct transform are carried out to the medical image to be measured respectively, obtain coefficient square to be measured
Battle array；The two-value symbol for extracting the middle low frequency coefficient of preset quantity described in the coefficient matrix to be measured, using as the doctor to be measured
Learn the eigenvectors matrix of image；
Eigenvectors matrix to the medical image to be measured and the logical key carry out XOR operation, obtain it is described to
Survey the watermark information matrix encrypted in medical image.
Preferably, the pixel grey scale value matrix to the binary bitmap carries out Arnold conversion, is encrypted
Watermark information matrix, comprising:
Initialize the encryption coefficient matrix of Arnold conversion；
According to the size of the encryption coefficient matrix and the binary bitmap, to the pixel of the binary bitmap
Gray scale value matrix carries out the encryption shuffle operation of preset times, the watermark information matrix encrypted.
Preferably, exclusive or fortune is carried out in the eigenvectors matrix to the medical image to be measured and the logical key
It calculates, after obtaining the watermark information matrix encrypted in the medical image to be measured, further includes:
It is restored and is requested according to zero watermarking, obtain the encryption coefficient matrix in initialization procedure；
According to the encryption coefficient matrix, the size of the binary bitmap, the preset times, to the encryption
Watermark information matrix carries out Arnold inverse transformation, obtains original binary bitmap.
Preferably, the two-value symbol for extracting the middle low frequency coefficient of preset quantity in the coefficient matrix, using as institute
State the eigenvectors matrix of original medical image, comprising:
The middle low frequency coefficient for extracting 4*8 in the coefficient matrix, obtains the coefficient matrix of 4*8；By the coefficient square of the 4*8
Battle array is converted into the coefficient matrix of 1*32, and rises maintenance and operation by row and calculate to obtain the coefficient matrix of 32*32；
The middle low frequency coefficient for being more than or equal to 0 in the coefficient matrix of the 32*32 is assigned a value of 1, the middle low frequency coefficient less than 0
It is assigned a value of 0, obtains the eigenvectors matrix of the original medical image.
Second aspect, this application provides a kind of medical image zero watermarking flush mounting based on NSCT combined transformation, packet
It includes:
Original image obtains module: the binary watermarking figure for obtaining original medical image and being generated according to patient information
Picture；
Primitive character extraction module: NSCT change is carried out respectively for the pixel grey scale value matrix to the original medical image
Change, RDWT transformation and dct transform, obtain coefficient matrix；Extract two of the middle low frequency coefficient of preset quantity in the coefficient matrix
It is worth symbol, using the eigenvectors matrix as the original medical image；
Watermark encrypting module: Arnold conversion is carried out for the pixel grey scale value matrix to the binary bitmap, is obtained
To the watermark information matrix of encryption；
Watermark embedding module: exclusive or fortune is carried out for the watermark information matrix to described eigenvector matrix and the encryption
It calculates, logical key matrix is obtained, to realize the insertion of zero watermarking.
Preferably, further includes:
Testing image determining module: requesting for being extracted according to zero watermarking, determines the medical image to be measured for having zero watermarking；
Characteristic extracting module to be measured: for carrying out NSCT transformation, RDWT transformation and DCT respectively to the medical image to be measured
Transformation, obtains coefficient matrix to be measured；Extract the two-value symbol of the middle low frequency coefficient of preset quantity described in the coefficient matrix to be measured
Number, using the eigenvectors matrix as the medical image to be measured；
Watermark extracting module: for the medical image to be measured eigenvectors matrix and the logical key carry out it is different
Or operation, obtain the watermark information matrix encrypted in the medical image to be measured.
Preferably, the watermark encrypting module is specifically used for:
Initialize the encryption coefficient matrix of Arnold conversion；According to the encryption coefficient matrix and the binary bitmap
Size, the encryption shuffle operation of preset times is carried out to the pixel grey scale value matrix of the binary bitmap, is encrypted
Watermark information matrix.
The third aspect, this application provides a kind of medical image zero watermarking embedded equipment based on NSCT combined transformation, packet
It includes:
Memory: for storing computer program；
Processor: as described above a kind of based on NSCT combined transformation to realize for executing the computer program
The step of medical image zero watermarking embedding grammar.
Fourth aspect is stored with computer on the readable storage medium storing program for executing this application provides a kind of readable storage medium storing program for executing
Program, for realizing a kind of medicine based on NSCT combined transformation as described above when the computer program is executed by processor
The step of image zero watermarking embedding grammar.
A kind of medical image zero watermarking embedding grammar, device, equipment based on NSCT combined transformation provided herein
And readable storage medium storing program for executing, scheme include: the binary bitmap for obtaining original medical image and being generated according to patient information；To original
The pixel grey scale value matrix of beginning medical image carries out NSCT transformation, RDWT transformation and dct transform respectively, obtains coefficient matrix；It mentions
The two-value symbol for taking the middle low frequency coefficient of preset quantity in coefficient matrix, using the eigenvectors matrix as original medical image；
Arnold conversion, the watermark information matrix encrypted are carried out to the pixel grey scale value matrix of binary bitmap；To feature to
Moment matrix and the watermark information matrix of encryption carry out XOR operation, logical key matrix are obtained, to realize the insertion of zero watermarking.
As it can be seen that mixing transformation and Arnold conversion of the program based on NSCT, RDWT, DCT are realized, in watermark telescopiny
In, firstly, extracting more robust medical image features vector, in conjunction with NSCT, RDWT, DCT to resist geometric attack.Its
It is secondary, using Arnold conversion encrypted watermark, enhance the safety of watermark information.Finally, realizing watermark using zero watermarking technology
Insertion, ensure that the integrality, watermark capacity and stealth of medical image, avoids traditional watermark embedding technique to original image
Defect caused by data modification ensure that the quality of medical image.Therefore, even if patient information is attacked by intentionally or unintentionally
It hits, as long as unauthorized user does not know key, just can not crack out medical image and watermark, so that the personal information of patient obtains
Really protection.
Detailed description of the invention
It, below will be to embodiment or existing for the clearer technical solution for illustrating the embodiment of the present application or the prior art
Attached drawing needed in technical description is briefly described, it should be apparent that, the accompanying drawings in the following description is only this Shen
Some embodiments please for those of ordinary skill in the art without creative efforts, can be with root
Other attached drawings are obtained according to these attached drawings.
Fig. 1 is a kind of medical image zero watermarking embedding grammar embodiment based on NSCT combined transformation provided herein
One implementation flow chart；
Fig. 2 is a kind of medical image zero watermarking embedding grammar embodiment based on NSCT combined transformation provided herein
One NSP schematic illustration；
Fig. 3 is a kind of medical image zero watermarking embedding grammar embodiment based on NSCT combined transformation provided herein
One NSDFB schematic illustration；
Fig. 4 is a kind of medical image zero watermarking embedding grammar embodiment based on NSCT combined transformation provided herein
One RDWT converts schematic diagram；
Fig. 5 is a kind of medical image zero watermarking embedding grammar embodiment based on NSCT combined transformation provided herein
Two implementation flow chart；
Fig. 6 is a kind of medical image zero watermarking flush mounting embodiment based on NSCT combined transformation provided herein
Functional block diagram.
Specific embodiment
The core of the application be to provide a kind of medical image zero watermarking embedding grammar based on NSCT combined transformation, device,
Equipment and readable storage medium storing program for executing are compensated for by combining the feature vector of encrypted medical image, cryptography and zero watermarking technology
The shortcomings that traditional digital watermark method cannot protect medical image itself has very strong robustness and invisible
Property, the privacy information of patient and the data safety of medical image can be protected simultaneously.
In order to make those skilled in the art more fully understand application scheme, with reference to the accompanying drawings and detailed description
The application is described in further detail.Obviously, described embodiments are only a part of embodiments of the present application, rather than
Whole embodiments.Based on the embodiment in the application, those of ordinary skill in the art are not making creative work premise
Under every other embodiment obtained, shall fall in the protection scope of this application.
Below to a kind of medical image zero watermarking embedding grammar embodiment based on NSCT combined transformation provided by the present application
One is introduced, and referring to Fig. 1, embodiment one includes:
S101, the binary bitmap for obtaining original medical image and being generated according to patient information；
S102, NSCT transformation, RDWT transformation and DCT are carried out respectively to the pixel grey scale value matrix of the original medical image
Transformation, obtains coefficient matrix；The two-value symbol for extracting the middle low frequency coefficient of preset quantity in the coefficient matrix, using as described
The eigenvectors matrix of original medical image；
S103, Arnold conversion, the watermark encrypted are carried out to the pixel grey scale value matrix of the binary bitmap
Information matrix；
S104, XOR operation is carried out to the watermark information matrix of described eigenvector matrix and the encryption, obtains logic
Cipher key matrix, to realize the insertion of zero watermarking.
Above-mentioned original medical image is specifically as follows ultrasonic wave, X-ray photograph, CT, MRI etc..
As described above, the present embodiment is based on NSCT transformation, RDWT transformation, dct transform, Arnold conversion realization, divide below
It is other that four kinds of transformation are introduced:
NSCT transformation, i.e. non-down sampling profile convert, and are filtered based on non-lower sampling pyramid (NSP) and non-lower sampling direction
The transformation of wave device (NSDFB).NSP reduces the sampling distortion of filter by the multi-resolution decomposition of image, and eliminates and adopt
Sample and down-sampling, it is ensured that translation invariance, such as Fig. 2 are divided into two grades.Signal is once decomposed into two round belts by NSDFB
Sub-filter, every time in proportion decompose after subgraph size be it is constant, can retain more details and effectively, with
It reduces the distortion of filter and obtains translation invariance, such as Fig. 3 is the segmentation figure of two scales.That is, NSP is by image
It is multiple dimensioned to ensure to be decomposed into high and low frequency, and high-frequency sub-band is decomposed into multiple by NSDFB, and the subband of different directions ensures in many ways
Tropism, and low frequency part continuation is decomposed according to pyramid model, so that NSCT has good translation invariance, it can be with
Geometric attack is resisted well.
RDWT transformation, i.e. redundant discrete small wave converting, it ensures translation invariance by eliminating down-sampling, but due to defeated
Image size remains unchanged out, therefore can generate a large amount of memory spaces, and stores more features for next stage, is RDWT below
Forward conversion:
Wherein, h [- k] and g [- k] indicates to pass through the low pass and high-pass filter of RDWT positive-going transition；cjAnd djIt is positive change
J-th of coefficient after changing.As shown in figure 4, the feature of the LL part signal extracted after RDWT positive-going transition, other three parts
The details or difference of signal are provided, and LL subband is passed to RDWT transformation.
Dct transform, i.e. discrete cosine transform are the various numbers for space area image to be transformed to frequency domain to analyze
One of word transform method is widely used in data or compression of images.The working principle of DCT is the high frequency components reduced in image,
This part corresponds to detailed information, such as texture edge etc. in image, insensitive to human visual system, need to only retain low
Frequency part, and low frequency part focuses on the big energy of image, and to improve the robustness and crushing resistance of watermarking algorithm, DCT is public
Formula is as follows:
Wherein i and j is the sampled value of image space domain, and u and v are the sampled values of image transform domain, N be image length and
Width.In general, image is rectangular in Digital Image Processing, if it is not, being generally filled with, discrete cosine transform is carried out.
Arnold conversion, i.e. Arnold Cat Map.Chaos is a kind of seemingly random movement, is referred in deterministic system
The similar random process of middle appearance.Therefore, there are its initial value and parameter, it will be able to generate this chaos system.Most write
A kind of chaos system of name is Arnold conversion, and the formula of Arnold direct transform and inverse transformation is respectively as follows:
Wherein (xn,yn) be original watermark image pixel coordinate, (xn+1,yn+1) it is pixel after watermarking images n times iteration
Coordinate, a, b, c, d are positive integer, are one-to-one mappings to ensure to map, N is the width or height of watermarking images.Due to
Arnold conversion has periodically, that is, if position (xn+1,yn+1) by T iterated transform, then it will return to raw bits
It sets.T is the change-over period, i.e. the number of iterations, and depends on parameter a, b, c, d, when changing these values, the phase of pixel
Closing property will change, that is, entirely different effect be generated, so these parameters may be used as key.According to related scholar to from
The periodic analysis of Arnold conversion is dissipated, conclusion is, for any N > 2, the period of Arnold conversion is T≤N2/2, this is
Result best so far.
As described above, the present embodiment extracts and becomes by NSCT when extracting the feature vector of original medical image
Change, RDWT transformation, dct transform obtain the two-value symbol of the middle low frequency coefficient of preset quantity in coefficient matrix, using as original doctor
The eigenvectors matrix of image is learned, the foundation of the extracting mode is as follows:
The main reason for major part medical image watermarking algorithm resist geometric attacks ability is poor at present is: people are by digital watermarking
Be embedded in pixel or transformation coefficient, the slight geometric transformation of medical image, frequently result in pixel value or transform coefficient values have compared with
Big variation, will make the watermark of insertion very easily under attack in this way.If reflection medical image geometrical feature can be found
Feature vector, then the characteristic value of the image will not occur significantly to be mutated substantially when small geometric transformation occurs for image.
By the coefficient matrix observation to a large amount of medical image, the present embodiment discovery ought carry out medical image features in the manner described above
When extraction, when carrying out common geometric transformation extraction feature to a medical image, the size of Low Medium Frequency coefficient may be sent out
Raw some variations, but its coefficient symbols is held essentially constant.According to human vision property, visual impact of the low intermediate frequency signal to people
It is larger, the main feature of image is represent, therefore the Low Medium Frequency coefficient symbols sequence conduct of medical image selected by the present embodiment
The eigenvectors matrix of original medical image.
The present embodiment provides a kind of medical image zero watermarking embedding grammar based on NSCT combined transformation, by original
Medical image is analyzed by the coefficient matrix that NSCT, RDWT, dct transform extract, and finds the low of coefficient of utilization matrix
The two-value symbol sebolic addressing of frequency coefficient can be used as the feature vector of medical image, improve resist geometric attacks ability；It utilizes
Arnold encrypts watermarking images, improves the safety of watermark information；In combination with zero watermarking concept, water is realized
The insertion of official seal breath, ensure that the integrality, watermark capacity and stealth of medical image, interested without selecting in advance
Region can be used in remote environment.Therefore, even if patient information is attacked by intentionally or unintentionally, as long as unauthorized user
Do not know key, just can not crack out medical image and watermark, so that the personal information of patient is really protected.
Start that a kind of medical image zero watermarking insertion based on NSCT combined transformation provided by the present application is discussed in detail below
Embodiment of the method two, referring to Fig. 5, embodiment two is specifically included:
S501, the binary bitmap for obtaining original medical image and being generated according to patient information；
Specifically, selecting a significant two-value text image as the binary bitmap of insertion medical image, note
For Wn=w (i, j) | w (i, j)=0,1；}.Meanwhile the tenth for choosing a medical volume data is used as original medical image,
It is denoted as I (i, j), wherein Wn(i, j) and I (i, j) respectively indicate the grey scale pixel value of binary bitmap and original medical image.
S502, NSCT transformation, RDWT transformation and DCT are carried out respectively to the pixel grey scale value matrix of the original medical image
Transformation, obtains coefficient matrix；The two-value symbol for extracting the middle low frequency coefficient of 4*8 in the coefficient matrix, using as described original
The eigenvectors matrix of medical image；
Transform domain to original medical image EI (i, j) carry out feature extraction, specifically, to original medical image EI (i,
J) full figure NSCT-RDWT-DCT mixing transformation is carried out, obtains coefficient matrix D (i, j), is denoted as D (i, j)=HT (EI (i, j)).
Specifically, extracting the middle low frequency coefficient of 4*8 in the coefficient matrix, the coefficient matrix of 4*8 is obtained；By the 4*8
Coefficient matrix be converted into the coefficient matrix of 1*32, and rise a maintenance and operation by row and calculate to obtain the two-dimensional coefficient matrix of 32*32；It will be described
Middle low frequency coefficient in the two-dimensional coefficient matrix of 32*32 more than or equal to 0 is assigned a value of " 1 ", and the middle low frequency coefficient less than 0 is assigned a value of
" 0 " obtains the two-dimensional feature vector matrix of the original medical image.That is, by taking 4*8 feature system to D (i, j)
Number, is then converted into the coefficient matrix of 1*32, then rises a maintenance and operation by row and calculates to obtain 32*32 two-dimensional matrix, will be greater than or equal to 0
Number, is assigned a value of " 1 ", remaining is assigned a value of " 0 ", to obtain two values matrix C (i, j), using the feature vector as original medical image
Matrix.
S503, the encryption coefficient matrix for initializing Arnold conversion；According to the encryption coefficient matrix and the two-value water
The size of watermark image carries out the encryption shuffle operation of preset times to the pixel grey scale value matrix of the binary bitmap, obtains
To the watermark information matrix of encryption；
Firstly, encrypting matrix coefficient a, b, c, d according to initialization Arnold Cat Map scrambling binary system；Then, as before
The formula of the Arnold direct transform of text description, by scrambled matrix and digital watermarking Wn(i, j) does operation inner product, in conjunction with mod (N)
The watermark information matrix B W encryptedn(i, j).Wherein N is the length or width of binary bitmap, but digital watermarking image
It is usually square, therefore length and width is equal, thus completes the encryption of watermark.
S504, XOR operation is carried out to the watermark information matrix of described eigenvector matrix and the encryption, obtains logic
Cipher key matrix, to realize the insertion of zero watermarking；
The watermark information matrix B W of encryptionnThe insertion of (i, j), it is therefore intended that insertion watermark simultaneously obtains logical key.Specifically
, by the watermark information matrix B W of eigenvectors matrix C (i, j) and encryptionn(i, j) step-by-step carries out XOR operation one by one,
It embeds watermark data into encrypted image, while obtaining the logical key matrix K ey (i, j) of 32*32, it may be assumed that
Key (i, j)=C (i, j) ⊕ BWn(i, j)；
Save Key (i, j), behind extract watermark when to use.By the way that Key (i, j) is applied as key to third party,
The ownership and the right to use of original medical image can be obtained, to achieve the purpose that conservation medicine image.
S505, it is extracted and is requested according to zero watermarking, determine the medical image to be measured for having zero watermarking；
S506, NSCT transformation, RDWT transformation and dct transform are carried out respectively to the medical image to be measured, obtains system to be measured
Matrix number；The two-value symbol for extracting the middle low frequency coefficient of preset quantity described in the coefficient matrix to be measured, using as it is described to
Survey the eigenvectors matrix of medical image；
Extract medical image EI'(i, j to be measured first) feature vector, for the coefficient square for being different from aforementioned original image
Battle array, the coefficient matrix of medical image to be measured is known as coefficient matrix to be measured in the present embodiment.To medical image EI'(i, j to be measured)
NSCT-RDWT-DCT mixing transformation is carried out, coefficient matrix to be measured is obtained；By extracting D'(i, j) 4*8 characteristic coefficient is taken, so
It is converted into the coefficient matrix of 1*32 afterwards, then calculate to obtain the two-dimensional matrix of 32*32 by row liter maintenance and operation and does perceptual hash operation, it will
Number more than or equal to 0 is assigned a value of " 1 ", remaining is assigned a value of " 0 ", to obtain two values matrix C'(i, j), i.e., medical image to be measured
Eigenvectors matrix.Process is as follows:
D'(i, j)=HT (EI'(i, j))
C'(i, j)=pHash (D'(i, j))
S507, XOR operation is carried out to the eigenvectors matrix of the medical image to be measured and the logical key, obtained
The watermark information matrix encrypted in the medical image to be measured；
Logical key Key (i, j) is only needed when extracting watermark, does not need original image participation, is that a kind of zero watermarking mentions
Take algorithm.Specifically, by the eigenvectors matrix C'(i, j of encrypted image to be measured) and logical key Key (i, j) progress exclusive or fortune
It calculates, just extracts the watermark information matrix B W'n (i, j) of encryption:
BW'n (i, j)=Key (i, j) ⊕ C'(i, j)
S508, it is restored and is requested according to zero watermarking, obtain the encryption coefficient matrix in initialization procedure；
S509, according to the encryption coefficient matrix, the size of the binary bitmap, the preset times, to described
The watermark information matrix of encryption carries out Arnold inverse transformation, obtains original binary bitmap.
Obtain the two dimensional encryption matrix of initialization Arnold Cat Map scrambling two-value scrambled matrix coefficient a, b, c, d；So
Two dimensional encryption matrix and the encrypted watermark BW'n (i, j) extracted do operation inner product afterwards, and then carrying out mod (N) can restore
Watermarking images W'n (i, j), wherein N is the length or width of digital watermarking image, but digital watermarking image is usually square,
Therefore length and width is equal, thus completes the reduction of watermark.
The anti-conventional attack ability of watermark and resist geometric attacks ability to prove the present embodiment, it is real that the application has carried out emulation
It tests to realize verifying, specific as follows:
1, the anti-conventional attack ability of watermark
(1) Gaussian noise is added
Watermarking images when being 1% for Gaussian noise intensity are visually very fuzzy；For the watermark of extraction, mention
The average NC value of the watermark taken is that can obviously detect the presence of watermark equal to 0.89.When table 1 is that the anti-Gauss of watermark interferes
Detection data.From experimental data, it can be seen that, when it is 25% that Gaussian noise intensity, which is up to, the PSNR of image is down to
11.4095dB, the watermark related coefficient NC=0.80 at this moment extracted, remains to the presence for detecting watermark.This explanation uses the reality
Apply the anti-Gaussian noise ability that example has had.
Table 1
(2) JPEG compression is handled
JPEG compression is carried out to watermarking images as parameter using compression of images intensity percentage；It is for compressive strength
30% image, the figure have already appeared blocking artifact；For the watermark of extraction, average NC value is equal to 1.00.Table 2 is watermarking images
The experimental data of anti-JPEG compression.When compression quality is 4%, the presence of watermark still can detecte, NC=0.89, this says
It is bright to have very strong anti-JPEG compression ability using the embodiment.
Table 2
(3) median filter process
It is [3x3] for median filtering parameter, the medical image that filter times are 20 times, image obscured；For mentioning
The watermark taken, average NC value are equal to 0.80, and detection effect is obvious.Table 3 is the anti-median filtering data of watermarking images, from table
Out, when median filtering parameter is [7x7], and filtering number of repetition is 20, the presence of watermark still can be measured, average NC value etc.
In 0.64.
Table 3
2. watermark resist geometric attacks ability:
(1) rotation transformation
For 10 ° of medical image of watermarking images rotation, PSNR=22.7324dB, signal-to-noise ratio is very low；For the water of extraction
Print, can obviously detect the presence of watermark, and average NC value is equal to 0.80.Table 4 is watermark anti-rotation attack experiment data.From table
In it can be seen that average NC value is equal to 0.57 when watermarking images rotate 40 °, still can detecte the presence of watermark.
Table 4
(2) scale transformation
The watermarking images for being 0.3 for zoom factor, at this moment center image is smaller than original image；It is average for the watermark of extraction
NC value is equal to 0.80, can obviously detect the presence of watermark.Table 5, which is that watermark is nonshrink, puts attack experiment data, can from table 5
Arrive, when zoom factor greatly to 4 when, average NC value is equal to 1.00, can still measure watermark, illustrates that the embodiment has stronger nonshrink put
Ability.
Table 5
(3) translation transformation
4% is vertically moved down for watermarking images, at this moment PSNR=21.8269dB, signal-to-noise ratio are very low；For the water of extraction
Print, average NC value are equal to 0.80, can obviously detect the presence of watermark.Table 6 is the anti-translation transformation experimental data of watermark.From table
In learn when vertically move down 15% when, still can detecte the presence of watermark, therefore the embodiment has stronger anti-translation capability.
Table 6
(4) shearing attack
The case where for watermarking images by Y direction shearing 3%, at this moment bottom is cut relative to original medical image
Cut away a part；The watermark extracted at this time, average NC value are equal to 1.00, can obviously detect the presence of watermark.Table 7 is water
The experimental data for printing anti-shearing attack, the experimental data from table is it is found that the present embodiment has very strong anti-shear ability.
Table 7
By above description of test, a kind of medical image zero watermarking based on NSCT combined transformation provided in this embodiment
Embedding grammar has stronger anti-conventional attack and geometric attack ability, and the insertion of watermark does not influence former medical image.
Below to a kind of medical image zero watermarking flush mounting based on NSCT combined transformation provided by the embodiments of the present application
It is introduced, a kind of medical image zero watermarking flush mounting based on NSCT combined transformation described below and above-described one
Medical image zero watermarking embedding grammar of the kind based on NSCT combined transformation can correspond to each other reference.
As shown in fig. 6, the device includes:
Original image obtains module 601: the binary watermarking for obtaining original medical image and being generated according to patient information
Image；
Primitive character extraction module 602: it is carried out respectively for the pixel grey scale value matrix to the original medical image
NSCT transformation, RDWT transformation and dct transform, obtain coefficient matrix；Extract the middle low frequency system of preset quantity in the coefficient matrix
Several two-value symbol, using the eigenvectors matrix as the original medical image；
Watermark encrypting module 603: carrying out Arnold conversion for the pixel grey scale value matrix to the binary bitmap,
The watermark information matrix encrypted；
Watermark embedding module 604: it is carried out for the watermark information matrix to described eigenvector matrix and the encryption different
Or operation, logical key matrix is obtained, to realize the insertion of zero watermarking.
In some specific embodiments, further includes:
Testing image determining module: requesting for being extracted according to zero watermarking, determines the medical image to be measured for having zero watermarking；
Characteristic extracting module to be measured: for carrying out NSCT transformation, RDWT transformation and DCT respectively to the medical image to be measured
Transformation, obtains coefficient matrix to be measured；Extract the two-value symbol of the middle low frequency coefficient of preset quantity described in the coefficient matrix to be measured
Number, using the eigenvectors matrix as the medical image to be measured；
Watermark extracting module: for the medical image to be measured eigenvectors matrix and the logical key carry out it is different
Or operation, obtain the watermark information matrix encrypted in the medical image to be measured.
In some specific embodiments, the watermark encrypting module is specifically used for:
Initialize the encryption coefficient matrix of Arnold conversion；According to the encryption coefficient matrix and the binary bitmap
Size, the encryption shuffle operation of preset times is carried out to the pixel grey scale value matrix of the binary bitmap, is encrypted
Watermark information matrix.
A kind of medical image zero watermarking flush mounting based on NSCT combined transformation of the present embodiment is for realizing above-mentioned
A kind of medical image zero watermarking embedding grammar based on NSCT combined transformation, therefore before specific embodiment in the device is visible
The embodiment part of medical image zero watermarking embedding grammar of one of the text based on NSCT combined transformation, so, it is specific real
The mode of applying is referred to the description of corresponding various pieces embodiment, herein not reinflated introduction.
In addition, since a kind of medical image zero watermarking flush mounting based on NSCT combined transformation of the present embodiment is for real
A kind of existing medical image zero watermarking embedding grammar based on NSCT combined transformation above-mentioned, therefore the work of its effect and the above method
With corresponding, which is not described herein again.
In addition, present invention also provides a kind of medical image zero watermarking embedded equipment based on NSCT combined transformation, comprising:
Memory: for storing computer program；
Processor: a kind of based on NSCT combined transformation as previously described to realize for executing the computer program
Medical image zero watermarking embedding grammar the step of.
Finally, it is stored with computer program on the readable storage medium storing program for executing this application provides a kind of readable storage medium storing program for executing,
For realizing a kind of medicine figure based on NSCT combined transformation as previously described when the computer program is executed by processor
As the step of zero watermarking embedding grammar.
Each embodiment in this specification is described in a progressive manner, the highlights of each of the examples are with it is other
The difference of embodiment, same or similar part may refer to each other between each embodiment.For being filled disclosed in embodiment
For setting, since it is corresponded to the methods disclosed in the examples, so being described relatively simple, related place is referring to method part
Explanation.
The step of method described in conjunction with the examples disclosed in this document or algorithm, can directly be held with hardware, processor
The combination of capable software module or the two is implemented.Software module can be placed in random access memory (RAM), memory, read-only deposit
Reservoir (ROM), electrically programmable ROM, electrically erasable ROM, register, hard disk, moveable magnetic disc, CD-ROM or technology
In any other form of storage medium well known in field.
Scheme provided herein is described in detail above, specific case used herein is to the application's
Principle and embodiment is expounded, the present processes that the above embodiments are only used to help understand and its core
Thought；At the same time, for those skilled in the art, according to the thought of the application, in specific embodiment and application range
Upper there will be changes, in conclusion the contents of this specification should not be construed as limiting the present application.
Claims (10)
1. a kind of medical image zero watermarking embedding grammar based on NSCT combined transformation characterized by comprising
The binary bitmap for obtaining original medical image and being generated according to patient information；
NSCT transformation, RDWT transformation and dct transform are carried out to the pixel grey scale value matrix of the original medical image respectively, obtained
Coefficient matrix；The two-value symbol for extracting the middle low frequency coefficient of preset quantity in the coefficient matrix, using as the primitive medicine
The eigenvectors matrix of image；
Arnold conversion, the watermark information matrix encrypted are carried out to the pixel grey scale value matrix of the binary bitmap；
XOR operation is carried out to the watermark information matrix of described eigenvector matrix and the encryption, obtains logical key matrix,
To realize the insertion of zero watermarking.
2. the method as described in claim 1, which is characterized in that in the water to described eigenvector matrix and the encryption
It prints information matrix and carries out XOR operation, after obtaining logical key matrix, further includes:
It is extracted and is requested according to zero watermarking, determine the medical image to be measured for having zero watermarking；
NSCT transformation, RDWT transformation and dct transform are carried out to the medical image to be measured respectively, obtain coefficient matrix to be measured；It mentions
The two-value symbol for taking the middle low frequency coefficient of preset quantity described in the coefficient matrix to be measured, using as the medical image to be measured
Eigenvectors matrix；
Eigenvectors matrix and the logical key to the medical image to be measured carry out XOR operation, obtain the doctor to be measured
Learn the watermark information matrix encrypted in image.
3. method according to claim 2, which is characterized in that the pixel grey scale value matrix to the binary bitmap
Carry out Arnold conversion, the watermark information matrix encrypted, comprising:
Initialize the encryption coefficient matrix of Arnold conversion；
According to the size of the encryption coefficient matrix and the binary bitmap, to the pixel grey scale of the binary bitmap
Value matrix carries out the encryption shuffle operation of preset times, the watermark information matrix encrypted.
4. method as claimed in claim 3, which is characterized in that in the eigenvectors matrix to the medical image to be measured
XOR operation is carried out with the logical key also to wrap after obtaining the watermark information matrix encrypted in the medical image to be measured
It includes:
It is restored and is requested according to zero watermarking, obtain the encryption coefficient matrix in initialization procedure；
Watermark according to the encryption coefficient matrix, the size of the binary bitmap, the preset times, to the encryption
Information matrix carries out Arnold inverse transformation, obtains original binary bitmap.
5. the method as described in claim 1-4 any one, which is characterized in that described to extract present count in the coefficient matrix
The two-value symbol of the middle low frequency coefficient of amount, using the eigenvectors matrix as the original medical image, comprising:
The middle low frequency coefficient for extracting 4*8 in the coefficient matrix, obtains the coefficient matrix of 4*8；The coefficient matrix of the 4*8 is turned
It changes the coefficient matrix of 1*32 into, and rises maintenance and operation by row and calculate to obtain the coefficient matrix of 32*32；
The middle low frequency coefficient for being more than or equal to 0 in the coefficient matrix of the 32*32 is assigned a value of 1, the middle low frequency coefficient assignment less than 0
It is 0, obtains the eigenvectors matrix of the original medical image.
6. a kind of medical image zero watermarking flush mounting based on NSCT combined transformation characterized by comprising
Original image obtains module: the binary bitmap for obtaining original medical image and being generated according to patient information；
Primitive character extraction module: for the pixel grey scale value matrix to the original medical image carry out respectively NSCT transformation,
RDWT transformation and dct transform, obtain coefficient matrix；Extract the two-value symbol of the middle low frequency coefficient of preset quantity in the coefficient matrix
Number, using the eigenvectors matrix as the original medical image；
Watermark encrypting module: Arnold conversion is carried out for the pixel grey scale value matrix to the binary bitmap, is added
Close watermark information matrix；
Watermark embedding module: carrying out XOR operation for the watermark information matrix to described eigenvector matrix and the encryption,
Logical key matrix is obtained, to realize the insertion of zero watermarking.
7. device as claimed in claim 6, which is characterized in that further include:
Testing image determining module: requesting for being extracted according to zero watermarking, determines the medical image to be measured for having zero watermarking；
Characteristic extracting module to be measured: become for carrying out NSCT transformation, RDWT transformation and DCT respectively to the medical image to be measured
It changes, obtains coefficient matrix to be measured；The two-value symbol of the middle low frequency coefficient of preset quantity described in the coefficient matrix to be measured is extracted,
Using the eigenvectors matrix as the medical image to be measured；
Watermark extracting module: for the eigenvectors matrix and logical key progress exclusive or fortune to the medical image to be measured
It calculates, obtains the watermark information matrix encrypted in the medical image to be measured.
8. device as claimed in claim 7, which is characterized in that the watermark encrypting module is specifically used for:
Initialize the encryption coefficient matrix of Arnold conversion；According to the ruler of the encryption coefficient matrix and the binary bitmap
It is very little, the encryption shuffle operation of preset times, the water encrypted are carried out to the pixel grey scale value matrix of the binary bitmap
Print information matrix.
9. a kind of medical image zero watermarking embedded equipment based on NSCT combined transformation characterized by comprising
Memory: for storing computer program；
Processor: for executing the computer program, to realize that one kind as described in claim 1-5 any one is based on
The step of medical image zero watermarking embedding grammar of NSCT combined transformation.
10. a kind of readable storage medium storing program for executing, which is characterized in that be stored with computer program, the meter on the readable storage medium storing program for executing
NSCT combined transformation is based on when calculation machine program is executed by processor for realizing one kind as described in claim 1-5 any one
Medical image zero watermarking embedding grammar the step of.
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