CN103455966B - Digital watermark embedding apparatus, data waterprint embedded method and digital watermark detecting device - Google Patents

Abstract

The invention discloses a kind of digital watermark embedding apparatus, data waterprint embedded method and digital watermark detecting device, described digital watermark embedding apparatus includes: interface unit, obtains video data and digital watermark information；And processing unit, it is embedded in digital watermark information to video data.Described processing unit is configured such that being formed and be superimposed on the area of the watermark recovery on each image comprised in described video data by multiple pixels with designated value changes the most in a periodic manner according to the value of the symbol comprised in described digital watermark information, and the value of each pixel being specified to correction each image in described video data described in using and comprising in region that the watermark recovery corresponding to this image overlaps each other.

Description

Digital watermark embedding apparatus, data waterprint embedded method and digital watermark detecting device

Technical field

Embodiments described herein relates to be embedded in the digital watermark embedding of digital watermark information to video data Equipment, data waterprint embedded method, digital watermark embedding computer program and for detect in video data embed digital water The digital watermark detecting device of official seal breath.

Background technology

Became common in the last few years for transmitting the service of the video content of such as film via the Internet etc.. Before transmission, come encoding video content by Digital Right Management (DRM) technology.Prevent so because of DRM technology The bootlegging of video content or distribution.

But, many events occur, wherein, by using the image picking-up apparatus of such as camcorder to shoot On computer display or television monitor display video content and the video content of bootlegging is illegally disseminated.Cause Uncoded, so being difficult to prevent the distribution of the video content by video capture for the video content of display on display.

In view of situation above, have been developed for a kind of technology, its before transmission video data with the shape of digital watermarking Formula is embedded in the information of such as audience identification number to dynamic image data.If by using camcorder shooting shown Image carry out bootlegging and wherein embed the video data of digital watermarking, then digital watermarking keeps in the video data replicated Completely.Therefore, if distribution is shot and the video data of bootlegging by such simulation, then can be by from bootlegging Video data in detect digital watermarking and identify the identification number of the spectators illegally employing video content.Therefore, even if working as example As shot by simulation and time the video content of bootlegging is uploaded to video upload website, the manager of video content also may be used With from the information identification bootlegging source embedded in the video content uploaded.

Preferably, video data embeds digital watermarking, so that the digital watermarking embedded in video data is seen Many imperceptible.Make spectators imperceptible to embed digital watermarking in video data, it is preferred that to reduce because of numeral The existence of watermark and the change of brightness that causes, i.e. difference on pixel value between digital watermark embedding region and its outer peripheral areas Not.But, if the difference on pixel value is less between digital watermark embedding region and its outer peripheral areas, then when using such as When the standard of dynamic image expert group (MPEG) compresses the video data wherein embedding digital watermarking, digital watermarking may be lost Lose.Digital watermarking is also possible to can be because going out when shootings such as using camcorder wherein embeds the video data of digital watermarking Existing image fault etc. and lose.On the other hand, if between digital watermark embedding region and its outer peripheral areas on pixel value Difference relatively big, the most such problem occurs without, but in this case, digital watermarking becomes spectators and can feel.That is, because of Degree that pixel value can spatially change and so that the strong degree of digital watermarking is made for the existence of digital watermarking Between exist compromise.In order to solve this trade-off problem, invent various digital watermark technology (special for example, referring to the world Profit announces No.2007/102403).

At the such as digital watermark embedding apparatus disclosed in international patent publications No.2007/102403 to having equal to big Input signal in the dimension of N is embedded in the information as digital watermarking.This digital watermark embedding apparatus comes based on the information of embedding Generate (N-1) dimension pattern, generate N-dimensional embedded pattern by root value modulated periodic signal on this (N-1) dimension pattern, and By embedded pattern superposition on the input signals.

But, in the case of the technology disclosed in international patent publications No.2007/102403, whole embedded pattern Brightness changes.As a result, there is uniform luminance if embedding wherein the region of embedded pattern comprises and become almost without time domain The image such as sky changed, then may be perceived as the dynamic image wherein embedding digital watermarking seeming that image is in flicker.Additionally, The border having between two regions of different value embedded may become the most notable.This can cause wherein embedding digital watermarking The decline of image quality of dynamic image.

Summary of the invention

Therefore, the purpose of the application is to provide a kind of digital watermark embedding apparatus, and this digital watermark embedding apparatus can be with The image comprised in video data independently minimizes owing to the watermark information embedded in video data causes be likely to occur to regard The decline of the image quality of frequency evidence.

According to an embodiment, it is provided that a kind of digital watermark embedding apparatus.Described digital watermark embedding apparatus includes: connect Mouth unit, obtains video data and digital watermark information；And processing unit, it is embedded in described numeral water to described video data Official seal ceases.Described processing unit is configured to: make to regard described in multiple pixels with designated value are formed and are superimposed on The area of the watermark recovery on each image comprised in frequency evidence is according to the symbol comprised in described digital watermark information Value changes the most in a periodic manner, and by the institute using pixel corresponding described in described watermark recovery to have State each image being specified to correct in wherein said video data and the described watermark recovery corresponding with this image each other The value of each pixel comprised in overlapping region.

According to another embodiment, it is provided that a kind of digital watermark detecting device.Described digital watermark detecting device includes: Interface unit, obtains the video data wherein embedding digital watermark information；And processing unit, detect in described video data embedding The described digital watermark information entered.Described processing unit is configured to: for each image comprised in described video data Calculate for described whole image or the average pixel value of the reference zone for comprising watermark recovery, the face of described watermark recovery Long-pending with mate described digital watermarking in the phase place of the value of symbol that comprises or cycle change the most in a periodic manner； By to being included in the time period corresponding with symbol and mean pixel described in order arrange a group in temporal sequence Value carries out frequency transformation and calculates for describing the frequency spectrum how described average pixel value changes with time domain；And by from described Frequency spectrum extracts the frequency component corresponding with the mechanical periodicity of the described area of described watermark recovery and by according to described frequency The phase place of the described mechanical periodicity of the described area of the rate component described watermark recovery of calculating or cycle obtain the value of described symbol.

Element by specifically noting in the claims and combination are realized and obtain objects and advantages of the present invention.

It should be understood that above-mentioned summary description and detailed description below be all exemplary and illustrative rather than Restriction to the present invention for required protection.

Accompanying drawing explanation

Fig. 1 is the figure of the configuration illustrating the digital watermark embedding apparatus according to an embodiment in simplified form.

Fig. 2 be illustrate according to the processing unit of an embodiment be to video data be embedded in digital watermark information realize The block diagram of function.

Fig. 3 is the figure of the example that diagram watermark recovery time domain over one period changes.

Fig. 4 is the average pixel value being shown in reference zone by the corresponding relation with Fig. 3 curve over time Figure.

Fig. 5 is the figure of another example that diagram watermark recovery time domain over one period changes.

Fig. 6 is the average pixel value being shown in reference zone by the corresponding relation with Fig. 5 curve over time Figure.

Fig. 7 is the figure of another example of the time domain change of diagram watermark recovery.

Fig. 8 is the figure of an example of the relation between time in the past and the value of insertion symbol of diagram watermark recovery.

Fig. 9 is another example of the relation between time and the value of insertion symbol in the past of diagram watermark recovery Figure.

Figure 10 is another example of the relation between time and the value of insertion symbol in the past of diagram watermark recovery Figure.

Figure 11 be illustrate according to first embodiment by the processing unit in digital watermark embedding apparatus perform calculating The operational flowchart that the programme controlled digital watermark embedding of machine processes.

Figure 12 is the figure of another example of the time domain change of diagram watermark recovery.

Figure 13 is the figure of the configuration illustrating the digital watermark detecting device according to an embodiment in simplified form.

Figure 14 be diagram digital watermark detecting device in processing unit be detection video data on digital watermark information The block diagram of the function realized.

Figure 15 A is the figure of an example of the time domain change of the average pixel value in drawing reference region.

Figure 15 B is to be schematically illustrated to obtain by performing inverse frequency transform for the frequency component corresponding with triangular wave Average pixel value time domain change figure, wherein, from by Figure 15 A diagram average pixel value time domain change carry out Frequency transformation and the frequency spectrum that obtains extracts the frequency component corresponding with triangular wave.

Figure 16 A is the figure of another example of the time domain change of the average pixel value in drawing reference region.

Figure 16 B is to illustrate the figure of frequency component for the cycle corresponding with each value of symbol, wherein, from by for Each time period carries out frequency transformation to the time domain change of the average pixel value of the reference zone of diagram in Figure 16 A and obtains Frequency spectrum extracts the frequency component in the cycle corresponding with each value of symbol.

Figure 16 C is to illustrate the figure of frequency component for the cycle corresponding with each value of symbol, wherein, from by for Each time period carries out frequency transformation to the time domain change of the average pixel value of the reference zone of diagram in Figure 16 A and obtains Frequency spectrum extracts the frequency component in the cycle corresponding with each value of symbol.

Figure 17 is the operational flowchart that diagram digital watermark detecting processes, and at this digital watermark detecting, reason is in digital watermarking The computer program performed on processing unit in detection equipment controls.

Detailed description of the invention

Digital watermark embedding apparatus is described below with reference to accompanying drawings.According to digital watermark embedding apparatus disclosed herein, by The area with the watermark recovery that one group of pixel of particular value is formed changes with time domain, so that wherein superposition watermark recovery The average pixel value in region changes with time domain according to the value of the symbol comprised in the digital watermark information embedded.

Each image comprised in video data can be frame or field.It is complete that frame refers to comprise in video data Still image, and field refers to by only extracting the data in the row of odd-numbered or the row of even-numbered from frame and shape The still image become.

Fig. 1 is the figure of the configuration illustrating the digital watermark embedding apparatus according to an embodiment in simplified form.Numeral water Print embedded equipment 1 includes interface unit 11, memory element 12 and processing unit 13.Digital watermark embedding apparatus 1 is to video data It is embedded in the digital watermark information obtained via interface unit 11.

Interface unit 11 includes: video signal interface, for digital watermark embedding apparatus 1 is such as connected to dynamic image Input equipment such as camcorder (not shown) or image display device such as liquid crystal display (not shown)；And be used for The control circuit of video signal interface.Or, interface unit 11 may include that communication interface, for being set by digital watermark embedding Standby 1 is connected to meet such as Ethernet(Ethernet, registered trade mark) the communication network of communication standard；And connect for communication The control circuit of mouth.It addition, or, digital watermark embedding apparatus 1 is connected to for receiving via radio chains by interface unit 11 The antenna of the video data of road transmission, and include the circuit for the video data received via antenna is decoded.

Interface unit 11 obtains video data from dynamic image-input device or via communication network or antenna, and will regard Frequency is according to being sent to processing unit 13.

Interface unit 11 can also include the interface circuit such as USB (universal serial bus) meeting bus standard, in order to by user Interface arrangement such as keyboard or mouse are connected to digital watermark embedding apparatus 1.Then, from user's interface device or via communication network Network, interface unit 11 obtains the data to be embedded in video data as digital watermark information, and by acquired data It is sent to processing unit 13.

Digital watermark information comprise from following part select at least one identification number: the identification number of spectators, video counts According to the identification number of provider with wherein comprise the identification number of video playback apparatus of digital watermark embedding apparatus 1.Say at this patent In bright book, by such as one ratio of one of the multiple numerals of identification number etc. constituting spectators comprised in digital watermark information or character Special as symbol.Therefore, the symbol comprised in digital watermark information has one of multiple predetermined different value.Such as, if digital The symbol comprised in watermark information is 1 bit, then this symbol has value " 0 " or " 1 ".

Interface unit 11 receives the video data embedding digital watermarking from processing unit 13, and to image display device ratio As liquid crystal display output embeds the video data of digital watermarking.Or, interface unit 11 can connect to via communication network Other equipment to digital watermark embedding apparatus 1 sends the video data embedding digital watermarking.

Memory element 12 includes at least one being selected from semiconductor memory system, disk set and optical disc apparatus Device.Memory element 12 stores the computer program to perform on digital watermark embedding apparatus 1 and for embedding digital watermarking letter The various parameters that breath is to be used.Additionally, digital watermark information and the most do not embed the video data of digital watermark information One or more image comprised can be stored temporarily in memory element 12, until processing unit 13 establishes embedding numeral Till the video data of watermark.Memory element 12 can also store the video data which is embedded digital watermark information.

Processing unit 13 include one or more processor, memory circuitry such as random access memory and they outside Enclose circuit.Processing unit 13 controls the integrated operation of digital watermark embedding apparatus 1.

Processing unit 13 by superposition on each image in video data as one group of pixel with particular value Watermark recovery be embedded in digital watermark information to video data, wherein, the area of this watermark recovery according to digital watermarking believe The value of the symbol comprised in breath changes the most in a periodic manner.

Fig. 2 is the block diagram of the function that illustrated process unit 13 realizes for being embedded in digital watermark information to video data. Processing unit 13 includes watermark recovery signal generating unit 21 and watermark recovery superpositing unit 22.Constitute these unit of processing unit 13 It it is the functional module performing computer program on the processor by comprising in processing unit 13 and realizing.Or, watermark figure Case signal generating unit 21 and watermark recovery superpositing unit 22 can be arranged on digital watermark embedding respectively as independent operation circuit In equipment 1.

Watermark recovery signal generating unit 21 generates the water to embed in each image according to the value of symbol to be embedded It is patterned.In the present embodiment, watermark recovery is one group of one or more watermark block.Each watermark block includes one or many Individual pixel, and there is such as rectangular shape.Or, each watermark block can be circular, semicircle or triangle in shape. Each pixel comprised in watermark block has the particular value in addition to " 0 ".In the present embodiment, this particular value is used for correcting The brightness value of the respective pixel in the superposition image of watermark recovery on it.Watermark recovery signal generating unit 21 is in time with periodically Mode the quantity of watermark block is increased or decreased.When the quantity of watermark block increases, the area of watermark recovery increases.According to wanting The value of the symbol embedded, watermark recovery signal generating unit 21 changes phase place or the week of the periodicity time domain change of the area of watermark recovery Phase.As a result, the reference zone comprising watermark recovery region on the entire image or in a part for image it is defined as Average pixel value increases the most periodically and reduces, thus the average pixel value of periodic variation reference zone The phase place of time domain change or cycle.

Fig. 3 is the figure of an example of the time domain change illustrating watermark recovery over one period.In illustrated example In, each pixel in each watermark block comprised in watermark recovery has on the occasion of such as " 2 " as particular value.Therefore, Each watermark block shows itself with the form of luminous point；As a result, when the pixel comprised in superposition watermark recovery, the picture of superposition The value of element goes above original pixel value.

Fig. 3 illustrates 9 time domain continuous print images from time t to time (t+8).Rectangle watermark recovery 311 is at time t Place is superimposed upon on image 301.Then, subtract in the time interval from time t to time (t+4) along with the quantity of watermark block 312 Few, the area of the watermark recovery being superimposed upon on image reduces.Then, watermark recovery is reduced at time (t+4) place from image 302. After the time (t+4), the area of watermark recovery starts to increase, until the area of watermark recovery reaches again at time (t+8) place To the maximum in image 303.

Fig. 4 is to be shown in the area of watermark recovery putting down over time and in reference area with the relation corresponding with Fig. 3 All pixel value over time between the figure of curve chart of relation.In the upper curve figure of Fig. 4, abscissa express time, Vertical coordinate represents the area of watermark recovery.Curve chart 401 illustrates the area of watermark recovery from time t's to time (t+8) How to change in time interval.On the other hand, in lower curve figure, abscissa express time, vertical coordinate represents pixel value.Curve Figure 40 2 illustrates how the average pixel value of reference zone changes in the time interval from time t to time (t+8).In order to Should be readily appreciated that, it is assumed that in each image to as if fixing.

As shown in curve chart 401, the area of watermark recovery in the time interval from time t to time (t+8) with triangle The mode of ripple changes.As it has been described above, in shown example, each pixel in watermark recovery have on the occasion of.As a result, as Shown in curve chart 402, the average pixel value of reference zone reduces with the area of watermark recovery and reduces, and with the face of watermark recovery Amass and increase and increase.Therefore, average brightness value also changes with time domain in the way of triangular wave, and represents the change of average pixel value The phase place of the triangular wave changed is identical with the phase place of the triangular wave of the change of the area representing watermark recovery.

Fig. 5 be a diagram that the figure of another example of watermark recovery time domain change over one period.Illustrated In example, each pixel comprised in watermark recovery has negative value such as "-2 " as particular value.Therefore, each watermark block Itself is shown with the form of shaded block；As a result, when the pixel comprised in superposition watermark recovery, the value of the pixel of superposition becomes Original pixel value must be less than.

Fig. 5 illustrates 9 time domain continuous print images from time t to time (t+8).It is on image 501 folded at time t Add rectangle watermark recovery 511.Then, reduce in the time interval from time t to time (t+4) when the quantity of watermark block 512 Time, the area of the watermark recovery being superimposed upon on image reduces.Then, watermark recovery is reduced at time (t+4) place from image 502. After the time (t+4), the area of watermark recovery starts to increase, until the area of watermark recovery reaches again at time (t+8) place To the maximum in image 503.

Fig. 6 be with the relation corresponding with Fig. 5 be shown in watermark recovery area over time and comprise watermark figure Average pixel value in the region of case over time between the figure of curve chart of relation.In the upper curve figure of Fig. 6, horizontal The coordinate representation time, vertical coordinate represents the area of watermark recovery.Curve chart 601 illustrates the area of watermark recovery from time t How to change to the time interval of time (t+8).On the other hand, in lower curve figure, abscissa express time, vertical coordinate table Show pixel value.Curve chart 602 represent the average pixel value of reference zone in the time interval from time t to time (t+8) such as What change.

As shown in curve chart 601, the area of watermark recovery in the time interval from time t to time (t+8) with triangle The mode of ripple changes.In illustrated example, each pixel in watermark recovery has negative value.As a result, such as curve chart 602 Shown in, the average pixel value of reference zone reduces with the area of watermark recovery and increases, and increases with the area of watermark recovery And reduce.Therefore, average pixel value changes in triangular wave mode the most in time, and represents the triangle of the change of average pixel value The phase place of ripple is relative to the opposite in phase of the triangular wave of the change of the area representing watermark recovery.

Fig. 7 is the figure of another example of the time domain change of diagram watermark recovery.In illustrated example, watermark recovery In each pixel in each watermark block of comprising there are value such as " 2 " or "-2 " as particular value.But, also at this In example, determine the watermark recovery being superimposed upon on each image, so that the average pixel value of reference zone is with triangular wave Mode time to time change, just as the situation of the watermark recovery illustrated in Figure 5.

Fig. 7 illustrates 9 time domain continuous print images from time t to time (t+8).At time t, on image 701 Superposition rectangle watermark recovery 711.Each pixel comprised in watermark recovery 711 has a negative value, thus whole watermark recovery 711 Itself is shown with the form of hatching pattern.Then, have on the occasion of light point-like watermark block 713 quantity with there is negative value The ratio of the quantity of shade watermark block 712 is gradually increased in the time interval from time t to time (t+4).Then, in the time (t+4), in the image 702 at place, whole watermark recovery 711 shows itself with the form of light dot pattern.As a result, reference area The average pixel value in territory increases in the time interval from time t to time (t+4).After the time (t+4), have on the occasion of light The quantity of point-like watermark block 713 is gradually reduced with the ratio of the shade watermark block 712 with negative value, until whole watermark recovery exists Till time (t+8) place shows itself with the form of the hatching pattern in image 703 again.

As it has been described above, as example, the phase place changed by the time domain of the average pixel value in reference zone is represented to be wanted The value of the symbol embedded in video data.In this case, watermark recovery signal generating unit 21 is such as multiple for wherein comprising First image comprised in the time period of specifying of image and wherein one symbol of embedding determines the area of watermark recovery.Then, For second comprised in this time period and follow-up image, watermark recovery signal generating unit 21 determines will be on each image The area of the watermark recovery of superposition, so that the average pixel value of reference zone changes in triangular wave mode.Then, water It is patterned signal generating unit 21 by the area of watermark recovery that will determine for this image divided by the area of a watermark block, comes really Surely the quantity of the watermark block comprised is superimposed upon in the watermark recovery on image interested.The appointment time period is chosen as such as One times or several times equal to the cycle that the time domain of the area of watermark recovery changes.

Watermark recovery signal generating unit 21 determines the watermark recovery being superimposed upon on image interested, so that this watermark figure The shape of case is different from the shape of the watermark recovery of superposition on the image immediately following image interested.In such a situation it is preferred that It is to determine the shape of watermark recovery so that at one of two watermark recoveries being superimposed upon respectively on two time domain continuous print images Be not included in pattern another in.Such as, such as Fig. 3, as shown in 5 and 7, it is preferable that watermark recovery signal generating unit 21 determines to be wanted The layout of the watermark block being superimposed upon on image interested, so that this layout and the figure before and after image interested The layout of the watermark block in Xiang is uncorrelated.This makes the watermark recovery being superimposed upon on each image be not easy by spectators to feel Arrive, because the position of watermark block passes by change randomly in time.

It may further be preferable that watermark recovery signal generating unit 21 determines the layout of each watermark block, so that work as watermark The area of the watermark block comprised in any specific part in watermark recovery region when the area of pattern becomes maximum is also with triangle Ripple mode changes over.Even if this makes digital watermark detecting device described later to work as and is concerned only with the one of watermark recovery region Also the change of the area of watermark recovery can be detected during part.

Such as, when the area of watermark recovery becomes maximum, wherein the region of superposition watermark recovery is divided into N number of sub-block The integer of 2 (N be no less than), the area of each sub-block is not less than the area of a watermark block.Each sub-block presses grating (raster) scanning sequency is with ascending order serial number, such as, from 1 start and at N at terminate.Then, watermark recovery generates single Unit 21 determines the number of the sub-block wherein placing each watermark block by the value obtaining the kth element in random sequence Amount, wherein, the output of each of which of the element of random sequence falls value in the range of 1 to N (here, 1≤k≤m, wherein, m Expression to be superimposed upon the sum of the watermark block on image interested, and is defined as m≤N).By using for different The different random sequence of image, watermark recovery signal generating unit 21 may determine that will on image interested the watermark block of superposition Arrange so that this layout is uncorrelated with the layout of the watermark block in the image in image front and rear interested.

Or, in memory element 12, one or more watermark figures can be stored for each watermark recovery region in advance Case, in these watermark recoveries, the layout of watermark block is different from each other.Then, from corresponding to be superimposed upon image interested Watermark recovery area watermark recovery in, watermark recovery signal generating unit 21 can such as according to appointment order or by use Random sequence selects a watermark recovery.Appointment order herein is e.g. to ascending order or the fall of the numbering of watermark recovery distribution Sequence.

It addition, or, watermark recovery signal generating unit 21 can determine by using the method in addition to as mentioned above The shape of the watermark recovery being superimposed upon on each image.

Fig. 8 is the figure of an example of the relation being shown between the time in the past of watermark recovery and the value of insertion symbol. In the upper and lower curve chart of Fig. 8, abscissa express time, vertical coordinate represents the average pixel value of reference zone.Curve chart 801 Illustrate how the average pixel value of reference zone when value of symbol is " 0 " or " 1 " respectively changes over 802.

In illustrated example, when value of symbol is " 0 ", average pixel value is minimum (secretly) at time started t0, and And change into thereafter bright in the way of triangular wave, it is then changed to dark, is then changed to bright.On the other hand, it is " 1 " when value of symbol Time, average pixel value is maximum (bright) at time started t0, and changes into thereafter dark in the way of triangular wave, is then changed to Bright, it is then changed to dark.By this way, change relative to working as symbol when the time domain that value of symbol is average pixel value time " 0 " Value is that the time domain change of average pixel value time " 1 " differs 180 ° in phase place.

If watermark recovery comprises shade watermark block, then when the area minimum of watermark recovery, average pixel value is the highest.Cause This, when average pixel value from bright to time secretly and then to bright change, the area of watermark recovery in the order from minimum to maximum Then to minimum change.On the contrary, if watermark recovery comprises light point-like watermark block, then average when the area maximum of watermark recovery Pixel value is the highest.Therefore, when average pixel value from bright to time secretly and then to bright change, the area of watermark recovery is in the order Then change to maximum to minimum from maximum.

It is not necessarily intended to so that the time domain for a value of symbol average pixel value changes and average for another value of symbol Phase contrast between the time domain change of pixel value is equal to 180 °, but needs only be such that this phase contrast is sufficiently large that digital watermarking Detection equipment can detect this phase contrast.

Fig. 9 is another example of the relation being shown between the time in the past of watermark recovery and the value of insertion symbol Figure.In the upper and lower curve chart of Fig. 9, abscissa express time, vertical coordinate represents the average pixel value of reference zone.Curve chart 901 and 902 respectively illustrate when the time domain of the average pixel value for a value of symbol reference zone changes and for another The average pixel value of reference zone when phase contrast between the time domain change of the average pixel value of value of symbol reference zone is 180 ° How to change over.The time period corresponding with a symbol is represented with each double-headed arrow 910 of abscissa general parallel orientation, And the value of symbol that the numeric representation under each arrow is in this time period.

Curve chart 901 demonstrates big gap at the border 921 and 922 that symbol changes between " 0 " and " 1 ".In view of This point, by for each of symbol " 0 " and " 1 ", by the phase-shifts 90 ° of triangular wave, as shown in curve chart 902, water It is patterned signal generating unit 21 so that average pixel value smoothly changes on the border 923 and 924 that value of symbol changes.From And, watermark recovery signal generating unit 21 is so that the change spectators of value of symbol not easily feel.It is same in curve chart 902, It is being maintained at 180 ° for the phase contrast between symbol " 0 " and the triangular wave of " 1 ".

Or, the cycle of the change of the area of watermark recovery can be changed according to value of symbol, i.e. average in reference zone The cycle of the change of pixel value.

Figure 10 is another example of the relation being shown between the time in the past of watermark recovery and the value of insertion symbol Figure.Figure 10 upper, neutralize in lower curve figure, abscissa express time, vertical coordinate represents the average pixel value of reference zone.Bent Line chart 1001 and 1002 illustrates the average pixel value of reference zone when value of symbol is " 0 " or " 1 " respectively and becomes the most in time Change.In illustrated example, it is the half of the cycle T 2 for value of symbol " 0 " for the cycle T 1 of value of symbol " 1 ".Therefore, If it is assumed that cycle T 2 is by such as 8 shown in Fig. 3 image construction, then cycle T 1 is by four image constructions.Same at this In example, it is preferable that make wherein to embed the length of the time period of each symbol identical, and unrelated with value of symbol, in order to side Just the detection of value embedded.Such as, as in Fig. 10 by illustrate average pixel value for multiple symbol reference zones time Shown in the curve chart 1003 of territory change, when value of symbol is " 0 ", each time period 1010 is by the two of the change of average pixel value The individual cycle is constituted；On the other hand, when value of symbol is " 1 ", each time period 1010 is by four of the change of average pixel value Cycle is constituted.

The watermark recovery determined for each image is sent to watermark recovery superposition list by watermark recovery signal generating unit 21 Unit 22.

Watermark recovery superpositing unit 22 identifies the reference zone for each image.Then, watermark recovery superpositing unit The value of the respective pixel comprised in the 22 specific watermark blocks by the watermark recovery in use reference zone, corrects and this watermark The value of each pixel comprised in the region that block is overlapping.Such as, if each pixel comprised in this watermark block has value "-2 ", then the value of each pixel that watermark recovery superpositing unit 22 comprises from the region overlapping with watermark block deducts " 2 ".Phase Instead, if each pixel comprised in watermark block has value " 2 ", then watermark recovery superpositing unit 22 is to overlapping with watermark block The value of each pixel comprised in region adds " 2 ".

As it has been described above, watermark recovery superpositing unit 22 can embed many along seasonal effect in time series direction in video data Individual symbol.In this case, every time corresponding with the symbol embedded in the video data time period terminates, can be at image Upper superposition is for representing the given pattern of character boundary, and it continues until till the time period corresponding to next symbol starts.

Watermark recovery superpositing unit 22 stores the image being superimposed with watermark recovery on it in memory element 12.Or, water It is patterned superpositing unit 22 and can export the image being superimposed with watermark recovery on it via interface unit 11 to another equipment.

Figure 11 is to illustrate by according to the computer performed on the processing unit in the digital watermark embedding apparatus of the present embodiment The operational flowchart that programme controlled digital watermark embedding processes.Processing unit 13 is each for comprise in digital watermark information Individual semiology analysis numbers below watermark embedding processes.

The symbol that processing unit 13 comprises from the digital watermark information received via interface unit 11 select interested Symbol (step S101).Then, when the watermark recovery signal generating unit 21 in processing unit 13 arranges appointment in video data Between section, this appointment time period comprises the multiple images (step S102) wherein embedding symbol interested.

Multiple images that watermark recovery signal generating unit 21 comprised in chronological order from the appointment time period select interested Image (step S103).Then, watermark recovery signal generating unit 21 determines the watermark recovery being superimposed upon on image interested Area so that the average pixel value of reference zone changes over (step with phase place or the cycle of coupling value interested S104).Watermark recovery signal generating unit 21 determines the number of watermark block to be comprised in watermark recovery according to the area of watermark recovery Amount.Additionally, watermark recovery signal generating unit 21 determines the layout of the watermark block for image interested, so that for interested Image watermark recovery in shape from for immediately following its watermark recovery different (step S105) of image.Then, watermark Tern generation unit 21 transmits watermark recovery to watermark recovery superpositing unit 22.

Watermark recovery superpositing unit 22, by using the value of the respective pixel comprised in each watermark block, corrects and is somebody's turn to do The value (step S106) of each pixel comprised in the region that watermark block is overlapping.

Thereafter, processing unit 13 determines whether the appointment time period is over (step S107).If specifying the time period also Be not over (in step s 107 no), then processing unit 13 repeats the process from step S103 to step S107.The opposing party Face, if specifying the time period to be over (in step s 107 be), then processing unit 13 continues in digital watermark information The next semiology analysis watermark embedding comprised processes.The number of times that symbol lengths and symbol embed is predetermined, and, process single Unit 13 repeats embedding and processes, until reaching pre-determined number.Or, processing unit 13 can repeat embedding process, until embed with So much symbol that the length of dynamic image is allowed.

As it has been described above, according to the digital watermark embedding apparatus of the present embodiment, the face of the watermark recovery on image to be superimposed upon Amass and periodically change, change the average pixel value of reference zone the most periodically, the cycle of the time domain change of average pixel value Or phase place represents the value of insertion symbol.As a result, each pixel that digital watermark embedding apparatus can will comprise in watermark recovery Value be set to little constant value.Therefore, digital watermark embedding apparatus is possible not only to the image that comprises in video data independently Minimize because the watermark information embedded in video data causes the decline of the image quality of the video data being likely to occur, and It is also possible that spectators are difficult to visually identify the digital watermarking of embedding.Additionally, must the shape of watermark recovery of superposition because making Shape is different to prevent watermark recovery to be always superimposed upon on same specific region for each image, so digital watermark embedding Equipment is so that spectators are more difficult to visually identify the digital watermarking of embedding.

Digital watermark embedding apparatus can determine whether embedded in digital watermark information by following manner: the most from which Embed the average pixel value whether periodic variation detecting reference zone in the video data of digital watermark information.As a result, as Fruit replicates the video data wherein embedding digital watermark information by simulation shooting, as long as then reference zone is maintained at duplication In the image of video data, digital watermark information is maintained for completely.

According to another embodiment, digital watermark embedding apparatus can be embedded in number to each image in video data The multiple symbols comprised in word watermark information.In this case, multiple reference is set for each image in video data Region and the multiple watermark recoveries being included in each reference zone.Superposition in each reference zone and this reference zone Watermark recovery corresponds to a symbol.If additionally, the whole symbols comprised in digital watermark information to be embedded in each In image, then can arrange and specify the time period is to start at the first image in video data, and at last image Terminate.

The time domain change of the area of watermark recovery is not limited to triangle wave change.According to an alternate embodiment, watermark figure Case signal generating unit may determine that the area of the watermark recovery being superimposed upon on each image, so that the area of watermark recovery The specific frequency components of time domain change has and adds intensity values.Such as, watermark recovery signal generating unit may determine that and to be superimposed upon each The area of the watermark recovery on image, so that the area of watermark recovery sinusoidal variations in time.

According to another modified example, a symbol can have three or more probable values.In this case, such as The value of a symbol is determined by the phase place of change of the average pixel value of reference zone and the combination in cycle.Such as, maximum The phase place of the average pixel value of the reference zone in the first image that the preset time of change wherein one symbol of embedding comprises in section It is designated as " just ", and minimizes the phase place of the average pixel value of reference zone in the first image comprised in this time period It is designated as " bearing ".Additionally, when the time domain of average pixel value changes and has the period 1, time domain change is designated as " short ", And when the time domain of average pixel value changes and has the second round longer than the period 1, time domain change is designated as " length ".? This, it is assumed that the symbol in the cycle can have one of four probable values " 0 ", " 1 ", " 2 " and " 3 ".In this case, watermark Tern generation unit is the most respectively to phase place/cycle combination " just/short ", " negative/short ", " just/long " and " negative/length " apportioning cost " 0 " To " 3 ".

According to another modified example, when each symbol is that a bit and digital watermark information are by bit sequence table When showing, the processing unit in digital watermark embedding apparatus can entangle to bit sequence application by using error correcting code or error-detecging code Miscoding.Then, processing unit can be embedded in the symbol pattern of Error Correction of Coding to video data.Such as, processing unit is permissible Use CRC (CRC) as the example of error correcting code.In this case, processing unit can be by digital watermark information The bit sequence inside comprised is converted to CRC code, and is embedded in CRC code to video data.Need only be such that the flat of reference zone All pixel values differently change according to the value of symbol embedded.When embedding the symbol of multiple CRC coding in each image, Digital watermark detecting device may determine that the value of each insertion symbol, without understanding the flat of the reference zone for this symbol All relations between phase place or cycle and this value of symbol of the time domain change of pixel value.Digital watermark detecting device determines value embedded It is to draw remainder " 0 " when the bit sequence extracted from video data is divided by the same generator polynomial for generating CRC code Value.

Such as, if it is assumed that this generator polynomial as divisor is to comprise sequence in " 1011 " and digital watermark information " 111011 ", then corresponding with this bit sequence CRC code is given " 1110011010 ".

In this case, embed in the video data of digital watermark information from which, digital watermark detecting device obtain with The phase place of the time domain change of the average pixel value of the reference zone that each bit is corresponding or cycle.Then, digital watermark detecting Equipment by the value of symbol different to different phase places or period allocated obtain two bit sequences " 1110011010 " and “0001100101”.It follows that in order to determine from video data extract bit sequence be " 1110011010 " or " 0001100101 ", digital watermark detecting device by each of two bit sequences divided by divisor " 1011 ".Then, numeral water Print detection equipment may determine that " 1110011010 " that draw remainder " 0 " are to embed bit sequence, and by from this bit sequence Row are removed check bit " 010 ", it is possible to obtain the bit sequence of embedding.

According to another modified example, digital watermark embedding apparatus embeds digital watermark information, so that digital watermarking inspection When measurement equipment can identify the periodicity of the average pixel value of the reference zone corresponding with the value of symbol embedded in each image The phase place of territory change.For this purpose, digital watermark embedding apparatus can arrange multiple reference zone for each image, and And one of reference zone can be set to particular reference region.Then, the watermark recovery signal generating unit in processing unit determines For the watermark recovery of particular reference region, so that the average pixel value of particular reference region always becomes with the constant cycle Change.The watermark recovery arranged for particular reference region is referred to below as " reference pattern ".

Watermark recovery signal generating unit determines watermark recovery, so that any other reference zone of allocated insertion symbol The time domain change of average pixel value also will have the cycle identical with reference pattern.Additionally, watermark recovery signal generating unit is according to embedding The value of the symbol entered, determines that the time domain at the area of watermark recovery changes and the time domain change of area of reference pattern, i.e. reference Phase contrast between the time domain change of the time domain change of the average pixel value in region and the average pixel value of particular reference region.Example As, when value of symbol is " 0 ", watermark recovery signal generating unit generates watermark recovery, so that wherein embedding the reference area of this symbol The phase place of the time domain change of the average pixel value of the phase matched particular reference region of the time domain change of the average pixel value in territory.Separately On the one hand, when value of symbol is " 1 ", watermark recovery signal generating unit generates watermark recovery, so that wherein embedding the ginseng of this symbol The phase place of the time domain change of the average pixel value in territory, examination district changes relative to the time domain of the average pixel value of particular reference region Phase-shifts 90 ° or 180 °.

According to another modified example, may be made that regulation is not so that watermark recovery signal generating unit uses and whole reference The watermark recovery of the shape that region is overlapping.

Figure 12 is diagram watermark when making stipulations the watermark recovery not using the shape overlapping with whole reference zone The figure of the example how pattern changes over.In illustrated example, each pixel comprised in watermark recovery There is negative value such as "-2 " as particular value.

Figure 12 illustrates 7 time domain continuous print images from time t to time (t+6).There is the watermark figure of maximum area The watermark block 1212 of case 1211, i.e. maximum quantity is superimposed upon on image 1201 at time t.Then, from time t to time (t+ 3), the area of watermark recovery reduces, but after the time (t+3), the area of watermark recovery increases.Then, the face of watermark recovery Amass and become maximum in image 1202 again at time (t+6) place.In illustrated example, each image 1201 He On 1202, the either of which of the watermark recovery of superposition is not rectangular shape, but arranges multiple watermark block spaced apart relation to each other.

By this way, it is preferred that even if determining watermark recovery so that at the water of the watermark block with maximum quantity In the case of being patterned, watermark recovery also not exclusively overlaps with reference zone, and at the outer nose placed of watermark recovery It is set to be shorter than set-point.By being arranged such watermark recovery, even if at the figure of the background such as sky with uniform luminance In the case of Xiang, on it, the border in the region of superposition watermark recovery also becomes to be not easy to be felt.Therefore, digital watermarking is embedding Enter equipment can reduce further because the watermark recovery embedded causes the decline of the image quality of the video data being likely to occur. By this set-point empirically determined, and this set-point arranges to be equal to the width such as with the watermark recovery of maximum area Or 1st/1st to three/2nd of height.

It follows that regarding providing detection by the digital watermark embedding apparatus according to above embodiment or its modified example The description of the digital watermark detecting device of the digital watermark information embedded in frequency evidence.

Figure 13 is the figure of the configuration illustrating the digital watermark detecting device according to an embodiment in simplified form.Numeral water Print detection equipment 2 includes interface unit 31, memory element 32 and processing unit 33.Digital watermark detecting device 2 detects via connecing The digital watermark information embedded in the video data that mouth unit 31 obtains.

Interface unit 31 includes: video signal interface, for digital watermark detecting device 2 is such as connected to dynamic image Input equipment such as camcorder (not shown)；And the control circuit for video signal interface.Or, interface unit 31 may include that communication interface, for digital watermark detecting device 2 is connected to meet such as Ethernet(Ethernet, and registration Trade mark) the communication network of communication standard；And the control circuit for communication interface.

Interface unit 31 obtains video data from dynamic image-input device or via communication network, and by video data It is sent to processing unit 33.

Interface unit 31 can also receive, from processing unit 33, the digital watermark information detected, and to via communication network Network is connected to other equipment of digital watermark detecting device 2 and sends digital watermark information.

Memory element 32 includes at least one dress being selected from semiconductor memory system, disk set and optical disc apparatus Put.Memory element 32 stores the computer program to perform on digital watermark detecting device 2 and to be used so that detection regards The various parameters of the digital watermark information embedded in frequency evidence.Such as, memory element 32 is stored on image the reference area limited The position in territory and scope and mapping table, this mapping table provides the time domain at value embedded and the average pixel value of reference zone to change Phase place or mapping between the cycle.Memory element 32 can also store detected digital watermark information, and memory element 32 is also The video data which is embedded digital watermark information can be stored.

Processing unit 33 include one or more processor, memory circuitry such as random access memory and they outside Enclose circuit.Processing unit 33 detects the digital watermark information embedded in video data.Additionally, processing unit 33 controls digital watermarking The integrated operation of detection equipment 2.

Figure 14 be illustrated process unit be the block diagram of function that the digital watermark information on detection video data realizes.

Processing unit 33 includes average pixel value computing unit 41, frequency conversion unit 42 and watermark information extraction unit 43.Processing unit 33 wherein embeds the camcorder of the video data of digital watermark information via interface unit 31 from shooting Or obtain video data from certain other equipment of storage video data.Then, processing unit 33 is by analyzing this video data Detect the digital watermark information of embedding.

Average pixel value computing unit 41 order in temporal sequence receives from processing unit 33 and embeds digital watermarking wherein The image comprised in the video data of information.Then, average pixel value computing unit 41 is for the reference area in each image Territory calculates average pixel value.If arranging multiple reference zone for each image, then average pixel value computing unit 41 is right Average pixel value is calculated in each reference zone.

If video data is to shoot regard original by not only shooting the video wherein embedding digital watermark information Background on frequency etc. and obtain simulation shooting video, then average pixel value computing unit 41 can from all of simulation shooting Video calculates average pixel value.Or, average pixel value computing unit 41 can pass through to each image application rim detection, Detect the dynamic image region comprising original video.In this case, average pixel value computing unit 41 detects dynamic image Reference zone in region.Additionally, in this case, average pixel value computing unit 41 is by using such as Sobel (Sobel) wave filter or Laplce (Laplacian) wave filter detect the edge on each image.Then, average picture Element value computing unit 41 determines in the edge extended the most in the horizontal direction, such as the longest in the top half of image Edge represents the top edge in the dynamic image region comprising original video.Equally, average pixel value computing unit 41 determines greatly In the limit that body extends in the horizontal direction, the such as longest edge edge in the latter half of image represents under dynamic image region Edge.Additionally, average pixel value computing unit 41 determines in the edge extended the most in vertical direction, such as at image Longest edge edge in left-half represents the left hand edge in dynamic image region, and the longest edge edge table in the right half part of image Show the right hand edge in dynamic image region.If the longest edge edge extended the most in the horizontal direction in the top half of image The half or less of the horizontal width of length e.g. image, then average pixel value computing unit 41 may determine that the top of image Edge is corresponding to the top edge in dynamic image region.If additionally, extended in horizontal direction substantially in the latter half of image The half or less of horizontal width of length e.g. image of longest edge edge, then average pixel value computing unit 41 can be true Determine the lower limb lower limb corresponding to dynamic image region of image.Equally, if at the left-half of image or right half part In the half or less of the vertical height of the length e.g. image of longest edge edge that extends the most in vertical direction, the most averagely Pixel value calculating unit 41 may determine that the left hand edge of image or right hand edge correspond respectively to dynamic image region left hand edge or Right hand edge.

Average pixel value computing unit 41 determines the top edge of reference zone, so that at the top edge in dynamic image region With the distance between the top edge of reference zone becomes and original the regarding of simulation shooting with the ratio of the height in dynamic image region Corresponding ratio in Pin is identical.Equally, average pixel value computing unit 41 may determine that any other edge of reference zone, with Make the height in distance between dynamic image region and the corresponding edge of reference zone and dynamic image region or width Ratio becomes identical with the corresponding ratio in original video.

Average pixel value computing unit 41 is by the average pixel value of whole image or the reference that obtains for each image The average pixel value in region is sent to frequency conversion unit 42.

Frequency conversion unit 42 is by arranging for each reference zone or for whole image with time series order Average pixel value set up one-dimensional vector.Then, by each time period corresponding with value of symbol one-dimensional to Amount carries out frequency transformation, and frequency conversion unit 42 obtains the frequency of the time domain change for representing the average pixel value in this time period Spectrum.Use such as fast fourier transform or discrete cosine transform to perform frequency transformation.Frequency conversion unit 42 can be passed through Use the technology for detection of such as pattern match for indicating the given pattern on time period border to identify each time period.

Frequency conversion unit 42 transmits for each reference zone or for whole figure to watermark information extraction unit 43 As that obtain, for representing the frequency spectrum of the time domain change of the average pixel value for each time period.

Based on for each reference zone or obtain for whole image, for represent for each time period The frequency spectrum of the time domain change of average pixel value, watermark information extraction unit 43 extracts the digital watermarking letter being embedded in video data Breath.

The average pixel value of reference zone also changes over, and shoots unless wherein embedded in the image of digital watermark information Video be still image.

Figure 15 A is the figure of an example of the time domain change of the average pixel value in drawing reference region.In Figure 15 A, horizontal The coordinate representation time, vertical coordinate represents pixel value.Curve chart 1501 in Figure 15 A is described in passes by reference zone in time The average pixel value of reference zone the most time dependent example during image modification.Exist in which the average of reference zone Image that change on pixel value is mainly due in reference zone rather than the situation of the change of the area of watermark recovery.At this In the case of sample, as found out from curve chart 1501, it is difficult to change extracting directly and watermark figure from the time domain of average pixel value The change component of the average pixel value that the change of the area of case is associated.

But, previously known for representing because the mean pixel of reference zone that causes of the change of area of watermark recovery The frequency of the time domain change of value.Such as, when the average pixel value of reference zone changes in triangular wave mode, such as front institute Stating, the frequency along the average pixel value of time-axis direction comprises the frequency component corresponding to triangular wave.

Figure 15 B is to be schematically illustrated to obtain by the following frequency component corresponding with triangular wave is performed inverse frequency transform The figure of the time domain change of the average pixel value obtained: this frequency component is from the time domain by the average pixel value described in Figure 15 A Change carries out extracting in the frequency spectrum of frequency transformation acquisition.In Figure 15 B, abscissa express time, vertical coordinate represents pixel value.? Curve chart 1502 in Figure 15 B describes by only obtaining to the frequency component application inverse frequency transform corresponding to triangular wave The time domain change of pixel value.As found out from curve chart 1502, by only extracting because the change of the area of watermark recovery is led The frequency component caused, only extracts because the periodicity of the average pixel value of reference zone that causes of the change of area of watermark recovery Time domain change component.When the video from the simulation shooting comprising background etc. detects watermark recovery, watermark information extraction unit 43 not only use reference zone, and use the whole image comprising noise such as background；If the change of the area of watermark recovery The cycle changed is different from background, then can detect symbol.

In view of this point, watermark information extraction unit 43 from for each reference zone or for whole image for often In the frequency spectrum of one time period acquisition, only extract and be associated with the periodically variable average pixel value of the area of watermark recovery The frequency component that time domain change is corresponding.Then, when the phase place changed by the time domain of average pixel value represents the value of insertion symbol, Watermark information extraction unit 43 obtains phase information from the frequency component extracted.Then, watermark information extraction unit 43 is such as By referring to the mapping table for providing the mapping between phase place and value of symbol, obtain the value of symbol corresponding to this phase place.

Or, can be by the average pixel value of the time domain change of the average pixel value of reference zone and particular reference region Phase contrast between time domain change determines value of symbol, as mentioned above.In this case, watermark information extraction unit 43 is from respectively For the frequency spectrum of reference zone and particular reference region extracts the frequency component being associated with the change of the area of watermark recovery. Then, watermark information extraction unit 43 obtains the phase of the frequency component extracted for reference zone and particular reference region respectively Position, and calculate the difference between the phase place in reference zone and the phase place in particular reference region.Watermark information extraction unit 43 The mapping table of the mapping between phase contrast and value of symbol is provided from memory element 32 retrieval.Watermark information extraction unit 43 is with reference to reflecting Firing table, and determine that the value of symbol of the phase contrast corresponding to being detected is the value of insertion symbol.

Or, if for representing that the bit sequence of the digital watermark information being embedded in video data is to use CRC code Error Correction of Coding, then the phase that watermark information extraction unit 43 changes according to the time domain of the average pixel value for each time period Position calculates the possible symbol pattern of each reference zone.Such as, if symbol is a bit, then supposing in each time In the case of the symbol of section is " 0 " or " 1 " respectively for identical phase place, watermark information extraction unit 43 sets up two patterns. Then, watermark information extraction unit 43 selects to be judged as faultless symbol pattern by CRC check.Such as, when three time periods In phase place difference time, be 0 °, 180 ° and 0 ° the most respectively, possible symbol pattern is (0,1,0) and (1,0,1).As it has been described above, Can also be by embedding CRC Parity Check Bits in advance as watermark symbol and by carrying out CRC when carrying out symbol decision Even-odd check carries out which pattern being the determination of correct symbol pattern about.

On the other hand, when the cycle changed by the time domain of the area of digital watermarking represents value of symbol, watermark information Extraction unit 43 obtains the strongest frequency component in the frequency component of the probable value that can use corresponding to this symbol, and obtains Must be corresponding to the cycle of the strongest frequency component.

Figure 16 A is the figure of another example of the time domain change of the average pixel value in drawing reference region.In Figure 16 A, Abscissa express time, vertical coordinate represents pixel value.Curve chart 1601 in Figure 16 A describes passes by reference zone in time Image modification time reference zone the most time dependent example of average pixel value.Double-headed arrow 1602 and 1603 points Do not represent the time period wherein embedding a symbol.As found out from curve chart 1601, it is difficult to examine in each time period Survey the cycle of the change of the average pixel value being associated with the change of the area of watermark recovery.

Figure 16 B and 16C is to illustrate from passing through for each time period the average picture of the reference zone of diagram Figure 16 A That the frequency spectrum that the time domain change of element value carries out frequency transformation and obtains extracts, for the cycle corresponding to each value of symbol The figure of frequency component.In Figure 16 B and 16C, abscissa represents the frequency component of extraction, and vertical coordinate represents the intensity of frequency spectrum.Figure 16B is corresponding to the time period 1602 in Figure 16 A, and Figure 16 C is corresponding to the time period 1603 in Figure 16 A.The frequency spectrum of triangular wave Comprise multiple frequency components in the cycle specific to triangular wave.

As illustrated in figure 16b, in the time period 1602, the intensity corresponding to the frequency component 1611 of cycle T 1 is more than correspondence Intensity in the frequency component 1612 of cycle T 2.As a result, watermark information extraction unit 43 infers the change of area of watermark recovery Cycle be T1.On the other hand, as shown in fig. 16 c, in the time period 1603, corresponding to the frequency component 1622 of cycle T 2 Intensity is more than the intensity of the frequency component 1621 corresponding to cycle T 1.As a result, watermark information extraction unit 43 infers watermark recovery Cycle of change of area be T2.

Watermark information extraction unit 43 provides the mapping of the mapping between cycle and value of symbol from memory element 32 retrieval Table.Watermark information extraction unit 43 is with reference to mapping table, and determines that the value of symbol in the cycle corresponding to being detected is insertion symbol Value.

With time series order, watermark information extraction unit 43 is by arranging that the value of symbol extracted carrys out reconstructing digital watermark Information.If arranging multiple reference zone, and insertion symbol, then watermark in each reference zone for each image Information extraction unit 43 is by arranging that with the order of insertion symbol the most in the picture the value of symbol for each reference zone comes Reconstructing digital watermark information.

Figure 17 is to illustrate the number controlled by the computer program performed on the processing unit 33 in digital watermark detecting device 2 The operational flowchart of word watermark detection process.Processing unit 33 comprises in the digital watermark information that embeds in video data Process below each semiology analysis.

Processing unit 33 selects in video data corresponding to the multiple images (step comprised in the appointment time period of a symbol Rapid 201).Average pixel value computing unit 41 in processing unit 33 calculates for reference zone for each image selected Or the average pixel value (step 202) for whole image.Then, average pixel value computing unit 41 by average pixel value to frequency Rate converter unit 42 transmits.

Frequency conversion unit 42 calculates the frequency spectrum of the time domain change of average pixel value by following manner: for each Time period carries out frequency transformation (step to the one-dimensional vector by setting up with time series order layout average pixel value S203).Then, frequency conversion unit 42 transmits frequency spectrum to watermark information extraction unit 43.

Watermark information extraction unit 43 extracts the frequency component that the change with the area of watermark recovery is associated from frequency spectrum (step S204).Then, watermark information extraction unit 43 calculates phase place or the cycle (step S205) of the frequency component extracted. The value of symbol corresponding with the phase place calculated or cycle is extracted as the value (step of insertion symbol by watermark information extraction unit 43 S206).

Processing unit 33 repeats numeral watermark detection process to obtain next symbol.It is being extracted predetermined quantity After symbol, processing unit 33 end number watermark detection process.

If arranging multiple reference zone for each image, then processing unit 33 repeats for each reference zone Step S202 to S206.

As it has been described above, the digital watermark detecting device according to the present embodiment can be from by the digital water according to previous embodiment The video data of print embedded equipment embedding digital watermark information extracts digital watermark information.Even if additionally, when by simulation hands When section shooting wherein embeds the video data of digital watermark information, the phase place of the time domain change of the area of watermark recovery or cycle are also Do not change.Therefore, digital watermark detecting device even can extract digital watermarking letter from the video data of so simulation shooting Breath.

The video data being embedded digital watermark information by digital watermark embedding apparatus can be color image data.Such as, If video data has the monochrome information for each of three kinds of color redness (R), green (G) and blue (B), then basis The digital watermark embedding apparatus of embodiment can for one of three kinds of colors or two or for all three color perform above Digital watermark embedding process.Or, digital watermark embedding apparatus can be for brightness or chrominance component or for saturation, color Degree etc. perform digital watermark embedding above and process.On the other hand, digital watermark detecting device can be for embedding digital watermarking One or more colors of information perform digital watermark detecting above and process.

Digital watermark embedding apparatus according to above embodiment is such as comprised in Set Top Box, server or individual calculus In machine.It is equipped with the equipment of digital watermark embedding apparatus when playing video data, for video data, i.e. via communication network Or the video content that antenna receives performs digital watermark embedding process above.If video data is the compression side by specifying The data of case compression, then each image in video data is decoded by this equipment according to the compression scheme specified.So After, this equipment will be stored in its buffer storage from the image of video data decoding with time series order.It follows that this sets From buffer storage, retrieve each image for time series order, perform digital watermark embedding and process, and make to show Show that unit display embeds the image of digital watermark information.

Furthermore, it is possible to provide for making computer real with record form on the medium that can be read by computer Now according to the computer program of each function of the processing unit in the digital watermark embedding apparatus of above embodiment.Equally, Can provide for making computer real now according to above with record form on the medium that can be read by computer Embodiment digital watermark detecting device in the computer program of each function of processing unit.

All examples described herein and conditional statement be intended for instruct purpose with help the reader understanding present invention and by The present inventor is for the thought of development this area contribution, and should be to be construed as being without limitation of example and the bar of so specific descriptions Part, the tissue of the such example in description is also not related to illustrate the Pros and Cons of the present invention.Although having been described in Embodiments of the invention, it is to be understood that in the case of without departing from the spirit and scope of the present invention, can enter for it Row various changes, substitute and change.

Claims (9)

1. a digital watermark embedding apparatus, including:

Interface unit, obtains video data and digital watermark information；And,

Processing unit, is embedded in described digital watermark information to described video data, wherein,

Described processing unit is configured such that the multiple pixels by having designated value form and be superimposed on described video counts The area of the watermark recovery on each image comprised according to according to the value of symbol comprised in described digital watermark information with week The mode of phase property changes over, and

Each image being specified to described in using to correct in described video data and the institute corresponding with each image described State the value of each pixel comprised in the region that watermark recovery overlaps each other.

Digital watermark embedding apparatus the most according to claim 1, wherein, described processing unit is configured to perform process, So that watermark recovery on the first image being superimposed upon in described video data in shape with to be superimposed upon described video Immediately following the watermark recovery difference on the second image of described first image in data.

Digital watermark embedding apparatus the most according to claim 2, wherein, described processing unit is configured to determine that wants superposition The shape of the described watermark recovery on described second image, so that being superimposed upon described first image and described second figure respectively As one of upper described watermark recovery be not contained in described watermark recovery another in.

Digital watermark embedding apparatus the most according to claim 2, wherein, described watermark recovery comprises by having described appointment At least one watermark block that at least one pixel of value is formed, and, along with the quantity of described watermark block is increased or decreased, described The area of watermark recovery increases or reduces, and wherein

Described processing unit is configured to determine that comprise in the described watermark recovery being superimposed upon on described second image described The layout of watermark block, so that the described water comprised in described layout and the described watermark recovery being superimposed upon on described first image The layout of print block is uncorrelated, so that the described watermark recovery being superimposed upon on described first image and be superimposed upon described second figure As upper described watermark recovery is the most different from each other.

Digital watermark embedding apparatus the most according to claim 4, wherein, described watermark recovery comprises and has the first designated value At least one first watermark block and at least one second watermark with second designated value different from described first designated value Block, and wherein

Described processing unit is configured to perform to be processed so that in the described watermark recovery being superimposed upon on described second image The ratio of the quantity of described second watermark block comprised and the quantity of described first watermark block and to be superimposed upon described first image On described watermark recovery in the quantity of described second watermark block that comprises different from the ratio of the quantity of described first watermark block.

Digital watermark embedding apparatus the most according to claim 1, wherein, when maximizing the area of described watermark recovery Described watermark recovery comprises multiple watermark block, and each watermark block is formed by the pixel with described designated value, and wherein

Described processing unit is arranged to the plurality of watermark block, so that in the plurality of watermark block, at least the first Watermark block and the second watermark block are spaced apart.

Digital watermark embedding apparatus the most according to claim 1, wherein, described processing unit is configured to perform process, So that the described change that the area of described watermark recovery when described symbol has the first value is in time in phase place with work as Described change when described symbol has second value different from described first value is different.

Digital watermark embedding apparatus the most according to claim 1, wherein, described processing unit is configured to perform process, So that the described change that the area of described watermark recovery when described symbol has the first value is in time on the cycle with work as Described change when described symbol has second value different from described first value is different.

9. a data waterprint embedded method, including:

Obtain video data and digital watermark information；

Make to be formed and be superimposed on, by multiple pixels with designated value, each image comprised in described video data On the area of watermark recovery change the most in a periodic manner according to the value of the symbol comprised in described digital watermark information Become；And

By each image of being specified to correct in described video data described in using with corresponding to each image described The region that overlaps each other of described watermark recovery in the value of each pixel that comprises, be embedded in described to described video data Digital watermark information.