CN102664014B - Blind audio watermark implementing method based on logarithmic quantization index modulation - Google Patents

Abstract

The invention discloses a blind audio watermark implementing method based on logarithmic quantization index modulation, and belongs to the technical field of audio watermarks. The blind audio watermark implementing method is characterized by including sufficiently utilizing robustness of vector norms and imperceptibility of the logarithmic quantization index modulation based on mu-law companding; improving safety and robustness of a watermark by the aid of a chaos sequence encryption watermark image; converting the sectioned vector norms of wavelet approximate components into a transform domain via the mu-law companding; then embedding an encryption binary watermark image; and extracting the binary watermark image after the watermark is attacked. The audio watermark algorithm has the advantages of high volume, fine tone, imperceptibility and robustness and low complexity, the watermark still can be correctly extracted by the aid of the method under various watermark attack conditions, and accordingly amplitude attack can be effectively resisted by the method.

Description

A kind of blind audio frequency watermark implementation method based on the logarithmic quantization index modulation

Technical field

The present invention relates to a kind of blind audio frequency watermark implementation method based on the logarithmic quantization index modulation, adopt this method, not only there are the characteristics that capacity is high, tonequality is good, also have advantages of that sentience is not good, robustness is good, complexity is low, in the situation that various Attack Digital Watermarkings, still can utilize this method correct extract watermark, and effectively opposing amplitude of the method is attacked.

Background technology

Digital watermarking (Digital Watermarking) is that the redundancy of the consciousness system (as vision or auditory system) of utilizing the people embeds some identification informations in the carriers such as image, audio frequency, but does not affect the use value of original vector.

According to the difference of watermark carrier, digital watermark can be divided into to several large classes such as video watermark, image watermark, audio frequency watermark.The comparative maturity that video, Image Watermarking Technique have developed at present, due to following reason, audio frequency watermark becomes emphasis and the focus of watermark research gradually: one, voice applications is extensive, is the important tool that the mankind exchange; Its two, have bulk redundancy in audio frequency, facilitate embed watermark information.But audio frequency watermark has with image watermark very large difference is arranged, main because: one, audio frequency is one-dimensional signal; Two, the mankind's auditory system is much sensitiveer than the mankind's vision system, on not sentience acoustically, implements more difficult than vision; Three, amount of audio data is larger, and is mainly used in the environment such as broadcast, online distribution, finds original audio very difficult, so the Detection and Extraction of watermark, not in requisition for original audio, realize blind Detecting in principle.

Generally, audio frequency watermark should meet following basic demand: (1) is sentience not: refer to and add after watermark the degree that affects the original audio quality; (2) robustness: refer to that the audio frequency that has added watermark can resist the degree of various attack; (3) capacity: refer to that per second is embedded into the quantity of the watermark of original audio; (4) complexity: the Time & Space Complexity that refers to algorithm.Usually above the requirement is conflicting, so we often select a balance according to the needs of practical application.

One of method of the audio frequency watermark adopted at present is: the audio frequency watermark based on spread spectrum.Major advantage is: can make signal improve antijamming capability in the low power transmissions situation, and disguised high, even the dropout of several frequency ranges, but restoring signal still, and guarantee to only have the receiver of known extensions function could detection signal, can realize blind Detecting.Major defect is: take too many frequency spectrum, embedded quantity is little; The blind Detecting prerequisite is containing between the sound signal of watermark and watermark random signal, reaching Complete Synchronization.For obtaining less watermark error extraction rate, watermark length must be enough large, but can increase like this detection complexity and increase time delay.

Two of the method for the audio frequency watermark adopted at present is: the audio frequency watermark based on quantization index modulation.Major advantage is: it is simple to have an algorithm, and complexity is low, and containing much information of embedding, easily realize blind extraction, and not sentience, reach balance between robustness and capacity.Major defect is: more responsive to noise ratio, this algorithm is used fixing quantization step, has introduced larger quantizing noise, the data fluctuations therefore caused for quantizing noise and the extraction error code that causes is higher.

Summary of the invention

At present, audio frequency watermark based on quantization index modulation is because it is more superior and can reach balance preferably at each aspect of performance, obtain extensive concern and fast development, but its quantizing process is all taked at present, be uniform quantization, fixing quantization step, although it is easy to realize, to noise-sensitive and its robustness and not the performance aspect sentience be not enough good.Analyze more top two kinds of watermarking algorithms, be not difficult to find that audio frequency watermark contradiction is both to need to improve the robustness of audio frequency watermark, need again to improve the not sentience of audio frequency watermark.For this reason, this research is considered from this two aspect, a kind of new Audio Watermarking Algorithm has been proposed, solve existing algorithm in robustness and the shortcoming aspect sentience not, and overcome the difficulty that complexity is high, the present invention effectively combines the not sentience of the robustness of vector norm and logarithmic quantization, by the mu-law companding, the vector norm of the wavelet approximation coefficients of segmentation is transformed into to transform domain, then embed the binary watermark upset, after Attack Digital Watermarking, extract binary watermark.The Audio Watermarking Algorithm that the present invention proposes, not only there are the characteristics that capacity is high, tonequality is good, also have advantages of that sentience is not good, robustness is good, complexity is low, in the situation that various Attack Digital Watermarkings, still can utilize this method correct extract watermark, and effectively opposing amplitude of the method is attacked.

The invention is characterized in, described method contains following steps successively:

Step (1) is at transmitting terminal, the telescopiny of audio frequency watermark, and step is as follows successively;

The original audio signal X={x of step (1.1) to setting _i, 1≤i≤L} carries out 2 grades of wavelet transform DWT, and the wavelet basis of employing is Db4, and then the number that wherein L is the original audio sampled point must be similar to component B={b _i, 1≤i≤L/4}, be divided into M * M mutual nonoverlapping frame S to approximate component _i, 1≤i≤M * M, M is positive integer, every frame S _iLength be

Every like this frame is hidden 1 bit-binary watermark information, and wherein the size of binary watermark is M * M;

Step (1.2) is according to formula:

σ _i＝||S _i||，

$S_i={\mathrm{\σ}}_i{u}_i^T,$

1 * p dimensional vector,

Calculate every frame S _iVector norm σ _i, 1≤i≤M * M, and allow σ _max=max (σ _i), 1≤i≤M * M;

The vector norm σ of step (1.3) to every frame _iDo the mu-law companding, specifically be calculated as follows:

c _i＝σ _i/σ _max，

λ _i＝ln(1+μc _i)/ln(1+μ)，

d＝λ _imodΔ，

Δ is predefined quantization step, 0≤Δ≤1, and μ is the parameter of mu-law companding, 0≤μ≤255;

Step (1.4) is utilized binary watermark W={w _Ij, 1≤i≤M, 1≤j≤M} and chaos sequence E={e _Ij, 1≤i≤M, 1≤j≤M}, obtain the watermarking images W={w upset _Ij, 1≤i≤M, 1≤j≤M}:

Xor operation, W={w _Ij, 1≤i≤M, 1≤j≤M} will be embedded in original audio signal X, and the i of i, j difference representative image matrix is capable, the j row,

If w _Ij=1, revise according to the following rules λ _i:

${\mathrm{\&lambda;}}_i^{\&prime;}=\left\{\begin{array}{c}{\mathrm{\&lambda;}}_i-\left({\mathrm{\&lambda;}}_i\mathrm{mod}\mathrm{\&Delta;}\right),\mathrm{if}(d<\mathrm{\&Delta;}/2)\\ {\mathrm{\&lambda;}}_i+\mathrm{\&Delta;}-\left({\mathrm{\&lambda;}}_i\mathrm{mod}\mathrm{\&Delta;}\right),\mathrm{if}(d>\mathrm{\&Delta;}/2)\end{array}\right.$

If w _Ij=0, revise according to the following rules λ _i:

λ _i'＝λ _i+Δ/2-(λ _imodΔ)；

Step (1.5) is utilized formula:

${\mathrm{\&sigma;}}_i^{\&prime;}=({(1+\mathrm{\&mu;})}^{{\mathrm{\&lambda;}}_i^{\&prime;}}-1)*{\mathrm{\&sigma;}}_{\max }/\mathrm{\&mu;},$

Be 1 * p dimensional vector, described as defined above,

Calculate the vector norm σ revised _i' and frame S _i', 1≤i≤M * M, and utilize frame S _i' the approximate component B'={b of reconstruct _i', 1≤i≤L/4};

Step (1.6) pairing approximation component B'={b _i', 1≤i≤L/4} carries out the discrete wavelet inverse transformation IDWT of 2 grades, obtains the sound signal X' containing watermark;

Step (2) is at receiving end, the leaching process of audio frequency watermark, and step is as follows successively;

Step (2.1) is to the sound signal X'={x containing watermark _i, 1≤i≤L} carries out the wavelet transform DWT of 2 grades, and the wavelet basis of employing is Db4, and wherein L is described as defined above, then must be similar to component B'={b _i', 1≤i≤L/4}, be divided into M * M mutual nonoverlapping frame S to approximate component _i', 1≤i≤M * M, every frame S _i' length be

Step (2.2) is according to formula:

σ _i'＝||S _i'||，

Calculate every frame S _i' vector norm σ _i', 1≤i≤M * M;

The vector norm σ of step (2.3) to every frame _i' do the mu-law companding, specifically be calculated as follows:

c _i'＝σ _i'/σ _max，

λ _i'＝ln(1+μc _i')/ln(1+μ)，

d＝λ _i'modΔ，

Δ is predefined quantization step, described as defined above, and μ is the parameter of mu-law companding, described as defined above;

Step (2.4) basis:

$w_{\mathrm{ij}}=\left\{\begin{array}{c}0,\mathrm{if}(d>\mathrm{\&Delta;}/4\mathrm{and\; d}<3*\mathrm{\&Delta;}/4)\\ 1,\mathrm{if}\left(\mathrm{others}\right)\end{array}\right.$

$W=W\&CirclePlus;E,$

Obtain original watermark image W={w _Ij, 1≤i≤M, 1≤j≤M}.

The blind audio frequency watermark implementation method based on the logarithmic quantization index modulation that the present invention proposes, its advantage mainly comprises: adopt logarithmic quantization to improve the not sentience of algorithm, adopt vector norm to improve the robustness of algorithm, adopt the encrypted chaotic array watermarking images to improve security and the robustness of watermark, by the mu-law companding, the vector norm of the wavelet approximation coefficients of segmentation is transformed into to transform domain, then embed the binary watermark of encrypting, after Attack Digital Watermarking, extract binary watermark.The Audio Watermarking Algorithm that the present invention proposes, not only there are the characteristics that capacity is high, tonequality is good, also have advantages of that sentience is not good, robustness is good, complexity is low, in the situation that various Attack Digital Watermarkings, still can utilize this method correct extract watermark, and effectively opposing amplitude of the method is attacked.

The accompanying drawing explanation

Fig. 1 is the merge module of Audio Watermarking Algorithm.

Fig. 2 is the extraction module of Audio Watermarking Algorithm.

Fig. 3 is the system chart of Audio Watermarking Algorithm.

Embodiment

The blind audio frequency watermark implementation method based on the logarithmic quantization index modulation that the present invention proposes comprises two parts of watermark merge module and watermark extracting module:

1) watermark merge module: for embed watermark information.To original audio signal X={x _i, 1≤i≤L} carries out the wavelet transform DWT of 2 grades, and the number that wherein L is the original audio sampled point must be similar to component B={b _i, 1≤i≤L/4}, be divided into M * M mutual nonoverlapping frame S to approximate component _i, 1≤i≤M * M, calculate every frame S _iVector norm σ _i, 1≤i≤M * M, and allow σ _max=max (σ _i), 1≤i≤M * M, and to the vector norm σ of every frame _iMake following calculating: c _i=σ _i/ σ _max, λ _i=ln (1+ μ c _i)/ln (1+ μ), d=λ _iThe mod Δ, Δ is predefined quantization step, μ is the parameter of mu-law companding.Utilize binary watermark W={w _Ij, 1≤i≤M, 1≤j≤M} and chaos sequence E={e _Ij, 1≤i≤M, 1≤j≤M} and formula

We can obtain the watermarking images W={w upset _Ij, 1≤i≤M, 1≤j≤M}, if w _Ij=1, revise according to the following rules λ _i: ${\mathrm{\&lambda;}}_i^{\&prime;}=\left\{\begin{array}{c}{\mathrm{\&lambda;}}_i-\left({\mathrm{\&lambda;}}_i\mathrm{mod}\mathrm{\&Delta;}\right),\mathrm{if}(d<\mathrm{\&Delta;}/2)\\ {\mathrm{\&lambda;}}_i+\mathrm{\&Delta;}-\left({\mathrm{\&lambda;}}_i\mathrm{mod}\mathrm{\&Delta;}\right),\mathrm{if}(d>\mathrm{\&Delta;}/2)\end{array}\right.,$ If w _Ij=0, revise according to the following rules λ _i: λ _i'=λ _i+ Δ/2-(λ _iThe mod Δ).Utilize formula: ${\mathrm{\&sigma;}}_i^{\&prime;}=({(1+\mathrm{\&mu;})}^{{\mathrm{\&lambda;}}_i^{\&prime;}}-1)*{\mathrm{\&sigma;}}_{\max }/\mathrm{\&mu;},S_i^{\&prime;}={\mathrm{\&sigma;}}_i^{\&prime;}{u}_i^T,$ Calculate the vector norm σ revised _i' and frame S _i', 1≤i≤M * M, and utilize frame S _i' the approximate component B'={b of reconstruct _i', 1≤i≤L/4}, the pairing approximation coefficient B '={ b _i', 1≤i≤L/4} carries out the discrete wavelet inverse transformation IDWT of 2 grades, and we can obtain the sound signal X' containing watermark;

2) watermark extracting module: for extracting watermark information.To audio frequency watermark signal X'={x _i, 1≤i≤L} carries out the wavelet transform DWT of 2 grades, must be similar to component B'={b _i', 1≤i≤L/4}, be divided into M * M mutual nonoverlapping frame S to approximate component _i', 1≤i≤M * M, according to formula: σ _i'=|| S _i' ||, calculate every frame S _i' vector norm σ _i', 1≤i≤M * M, to the vector norm σ of every frame _i' do to calculate as follows: c _i'=σ _i'/σ _max, λ _i'=ln (1+ μ c _i')/ln (1+ μ), d=λ _i' the mod Δ, Δ is predefined quantization step, μ is the parameter of mu-law companding, according to $w_{\mathrm{ij}}=\left\{\begin{array}{c}0,\mathrm{if}(d>\mathrm{\&Delta;}/4\mathrm{and\; d}<3*\mathrm{\&Delta;}/4)\\ 1,\mathrm{if}\left(\mathrm{others}\right)\end{array}\right.$ With $W=W\&CirclePlus;E,$ We can obtain original watermark image W={w _Ij, 1≤i≤M, 1≤j≤M}.

Below in conjunction with accompanying drawing, describe content of the present invention in detail:

Fig. 1 is based on the audio frequency watermark merge module of logarithmic quantization index modulation.As shown in Figure 1, original audio signal X is carried out to the wavelet transform DWT of 2 grades, the approximate component obtained is divided into to M * M mutual nonoverlapping frame, calculate the vector norm of every frame, then carry out the mu-law companding, embedding is by the binary watermark W of encrypted chaotic array, and then carry out the mu-law companding, calculate vector norm and this frame of revising, repeat said process until all watermark bit all embed, and utilize the frame reconstruct of revising to be similar to component, and the pairing approximation component carries out the discrete wavelet inverse transformation IDWT of 2 grades, we can obtain the sound signal X' containing watermark.

Fig. 2 is based on the audio frequency watermark extraction module of logarithmic quantization index modulation.As shown in Figure 2, sound signal X' containing watermark is carried out to the wavelet transform DWT of 2 grades, the approximate component obtained is divided into to M * M mutual nonoverlapping frame, calculate the vector norm of every frame, then carry out the mu-law companding, extraction, by the scale-of-two watermark bit, with the chaos sequence deciphering, obtains original binary watermark W.

Fig. 3 is the system chart of Audio Watermarking Algorithm.As shown in Figure 3, watermark information is embedded in initial carrier by the watermark merge module, after various attack, then extracts watermark information by the watermark extracting module.

Claims (1)

1. the blind audio frequency watermark implementation method based on the logarithmic quantization index modulation, the invention is characterized in, described method contains following steps successively:

Step (1) is at transmitting terminal, the telescopiny of audio frequency watermark, and step is as follows successively;

The original audio signal X={x of step (1.1) to setting _i, 1≤i≤L} carries out 2 grades of wavelet transform DWT, and the wavelet basis of employing is Db4, and then the number that wherein L is the original audio sampled point must be similar to component B={b _i, 1≤i≤L/4}, be divided into M * M mutual nonoverlapping frame S to approximate component _i, 1≤i≤M * M, M is positive integer, every frame S _iLength be

Every like this frame is hidden 1 bit-binary watermark information, and wherein the size of binary watermark is M * M;

Step (1.2) is according to formula:

σ _i=||S _i||,

$S_i={\mathrm{\&sigma;}}_i{u}_i^T,$

1 * p dimensional vector,

Calculate every frame S _iVector norm σ _i, 1≤i≤M * M, and allow σ _max=max (σ _i), 1≤i≤M * M;

The vector norm σ of step (1.3) to every frame _iDo the mu-law companding, specifically be calculated as follows:

c _i＝σ _i/σ _max，

λ _i＝ln(1+μc _i)/ln(1+μ)，

d＝λ _imodΔ，

Δ is predefined quantization step, 0≤Δ≤1, and μ is the parameter of mu-law companding, 0≤μ≤255;

Step (1.4) is utilized binary watermark W={w _Ij, 1≤i≤M, 1≤j≤M} and chaos sequence E={e _Ij, 1≤i≤M, 1≤j≤M}, obtain the watermarking images W={w upset _Ij, 1≤i≤M, 1≤j≤M}:

Xor operation, W={w _Ij, 1≤i≤M, 1≤j≤M} will be embedded in original audio signal X, and the i of i, j difference representative image matrix is capable, the j row,

If w _Ij=1, revise according to the following rules λ _i:

${\mathrm{\&lambda;}}_i^{\&prime;}=\left\{\begin{array}{c}{\mathrm{\&lambda;}}_i-\left({\mathrm{\&lambda;}}_i\mathrm{mod}\mathrm{\&Delta;}\right),\mathrm{if}(d<\mathrm{\&Delta;}/2)\\ {\mathrm{\&lambda;}}_i+\mathrm{\&Delta;}-\left({\mathrm{\&lambda;}}_i\mathrm{mod}\mathrm{\&Delta;}\right),\mathrm{if}(d>\mathrm{\&Delta;}/2)\end{array}\right.$

If w _Ij=0, revise according to the following rules λ _i:

λ _i'＝λ _i+Δ/2-(λ _imodΔ)；

Step (1.5) is utilized formula:

${\mathrm{\&sigma;}}_i^{\&prime;}=({(1+\mathrm{\&mu;})}^{{\mathrm{\&lambda;}}_i^{\&prime;}}-1)*{\mathrm{\&sigma;}}_{\max }/\mathrm{\&mu;},$ Be 1 * p dimensional vector, described as defined above,

Calculate the vector norm σ revised _i' and frame S _i', 1≤i≤M * M, and utilize frame S _i' the approximate component B'={b of reconstruct _i', 1≤i≤L/4};

Step (1.6) pairing approximation component B'={b _i', 1≤i≤L/4} carries out the discrete wavelet inverse transformation IDWT of 2 grades, obtains the sound signal X' containing watermark;

Step (2) is at receiving end, the leaching process of audio frequency watermark, and step is as follows successively;

Step (2.1) is to the sound signal X'={x containing watermark _i, 1≤i≤L} carries out the wavelet transform DWT of 2 grades, and the wavelet basis of employing is Db4, and wherein L is described as defined above, then must be similar to component B'={b _i', 1≤i≤L/4}, be divided into M * M mutual nonoverlapping frame S to approximate component _i', 1≤i≤M * M, every frame S _i' length be

Step (2.2) is according to formula: σ _i'=|| S _i' ||,

Calculate every frame S _i' vector norm σ _i', 1≤i≤M * M;

The vector norm σ of step (2.3) to every frame _i' do the mu-law companding, specifically be calculated as follows:

c _i'＝σ _i'/σ _max，

λ _i'＝ln(1+μc _i')/ln(1+μ)，

d＝λ _i'modΔ，

Δ is predefined quantization step, described as defined above, and μ is the parameter of mu-law companding, described as defined above;

Step (2.4) basis:

$w_{\mathrm{ij}}=\left\{\begin{array}{c}0,\mathrm{if}(d>\mathrm{\&Delta;}/4\mathrm{and\; d}<3*\mathrm{\&Delta;}/4)\\ 1,\mathrm{if}\left(\mathrm{others}\right)\end{array}\right.$

$W=W\&CirclePlus;E,$

Obtain original watermark image W={w _Ij, 1≤i≤M, 1≤j≤M}.

Images