CN103455966A - Digital watermark embedding equipment, digital watermark embedding method and digital watermark detecting equipment - Google Patents

Abstract

The invention discloses digital watermark embedding equipment, a digital watermark embedding method and digital watermark detecting equipment. The digital watermark embedding equipment comprises an interface unit and a processing unit, wherein the interface unit acquires video data and digital watermark information; and the processing unit embeds digital watermark information in the video data. By the processing unit, the area of watermark patterns which are formed by a plurality of pixels with designated values and are superposed on images in the video data is periodically changed along with time according to values of signs contained in the digital watermark information, and the images in the video data and values of pixels contained in areas, which are overlapped to one another, of the watermark patterns corresponding to the patterns are corrected by using the designated values.

Description

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

Technical field

Embodiment discussed in this article relates to digital watermark embedding apparatus, data waterprint embedded method, the digital watermarking embeddeding computer program for be embedded in digital watermark information to video data and the digital watermark detecting device of the digital watermark information that embeds for detection of video data.

Background technology

In the last few years, became common for the service of transmitting via the Internet etc. such as the video content of film.Before transmitting, by Digital Right Management (DRM) technology, come video content is encoded.Bootlegging or the distribution of such video content have been prevented because of the DRM technology.

Yet, many events have appearred, wherein, by use such as the image picking-up apparatus of camcorder take the video content shown on graphoscope or television monitor and the video content illegally copied by illegal distribution.Because the video content shown on display is not encoded, so be difficult to prevent the distribution by the video content of video capture.

In view of top situation, developed a kind of technology, its form with digital watermarking before transmitting video data is embedded in the information such as spectators' identification number to dynamic image data.If carry out the wherein video data of embed digital watermark of bootlegging by take shown image with camcorder, digital watermarking keeps complete in copied video data.Therefore, the video data illegally copied if distribution is taken by such simulation, can identify the illegal identification number that has used the spectators of video content by detecting digital watermarking the video data from bootlegging.Therefore, even the video content illegally copied when for example taking by simulation is uploaded to video while uploading website, the keeper of video content also can be from the information identification bootlegging source embedded the video content of uploading.

Preferably, embed digital watermark in video data, so that the digital watermarking spectators that embed in video data are imperceptible.For embed digital watermark in video data, make spectators imperceptible, preferably, reduce the variation of the brightness caused because of the existence of digital watermarking, i.e. digital watermarking embeds the difference on pixel value between zone and its outer peripheral areas.Yet less if digital watermarking embeds between zone and its outer peripheral areas the difference on pixel value, when use such as the standard of dynamic image expert group (MPEG) is compressed the video data of embed digital watermark wherein, digital watermarking may be lost.Digital watermarking also may be lost because of the image fault occurred when using camcorder etc. to take the video data of embed digital watermark wherein etc.On the other hand, larger if digital watermarking embeds between zone and its outer peripheral areas the difference on pixel value, such problem does not occur, but in this case, and the digital watermarking spectators that become can feel.That is, because the degree that the existence of digital watermarking makes pixel value spatially to change and can be so that exist compromise between the strong degree of digital watermarking.In order to solve this trade-off problem, various digital watermark technologies (for example,, with reference to international patent publications No.2007/102403) have been invented.

In international patent publications No.2007/102403 for example, disclosed digital watermark embedding apparatus is embedded in the information as digital watermarking to the input signal with the dimension that equals to be greater than N.This digital watermark embedding apparatus generates (N-1) dimension pattern based on embedding information, and the value modulated periodic signal by root on this (N-1) dimension pattern generates N dimension embedded pattern, and embedded pattern is superimposed upon on input signal.

Yet, in the situation that disclosed technology in international patent publications No.2007/102403, the brightness of whole embedded pattern changes.As a result, if embed therein in the zone of embedded pattern, comprise the image ratio that has uniform luminance and almost do not have time domain to change as sky, wherein the dynamic image of embed digital watermark is perceived as and seems that image is glimmering.In addition, the border had between two zones of different embedding values may become not remarkable.This can cause the wherein decline of the image quality of the dynamic image of embed digital watermark.

Summary of the invention

Therefore, the application's purpose is to provide a kind of digital watermark embedding apparatus, and this digital watermark embedding apparatus can independently minimize the decline that causes the image quality of the video data that may occur due to the watermark information embedded in video data with the image that comprises in video data.

According to an embodiment, provide a kind of digital watermark embedding apparatus.Described digital watermark embedding apparatus comprises: interface unit, obtain video data and digital watermark information; And processing unit, be embedded in described digital watermark information to described video data.Described processing unit is configured to: make the area that forms and be superimposed on the watermark recovery on each image comprised in described video data by a plurality of pixels with designated value change in periodic mode in time according to the value of the symbol comprised in described digital watermark information, and by the value of each pixel of comprising in the zone of using each image in proofreading and correct wherein said video data of the described designated value had in pixel corresponding described in described watermark recovery and the described watermark recovery corresponding with this image to overlap each other.

According to another embodiment, provide a kind of digital watermark detecting device.Described digital watermark detecting device comprises: interface unit, obtain the wherein video data of embed digital watermark information; And processing unit, detect in described video data the described digital watermark information embedded.Described processing unit is configured to: for each image calculation comprised in described video data for described whole image or for the average pixel value of the reference zone that comprises watermark recovery, the area of described watermark recovery with mate described digital watermarking in phase place or cycle of value of the symbol that comprises in periodic mode, change in time; By to being included in the time period corresponding with symbol and one group of described average pixel value arranging by the time sequence order carries out frequency transformation and calculates the frequency spectrum how changed with time domain for describing described average pixel value; And change by extracting with the cycle of the described area of described watermark recovery the value that the phase place of described cycle variation of corresponding frequency component and the described area by calculating described watermark recovery according to described frequency component or cycle obtain described symbol from described frequency spectrum.

To realize and obtain objects and advantages of the present invention by element and the combination of specifically noting in the claims.

It should be understood that above-mentioned summary description and following detailed description are all exemplary with illustrative, rather than to the restriction of the present invention for required protection.

The accompanying drawing explanation

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

Fig. 2 is that diagram is to be embedded in the block diagram of the function of digital watermark information realization to video data according to the processing unit of an embodiment.

Fig. 3 is the figure of an example of the time domain change of diagram watermark recovery on one-period.

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

Fig. 5 is the figure of another example of the time domain change of diagram watermark recovery on one-period.

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

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

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

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

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

Figure 11 is that the digital watermarking that the computer program carried out on the processing unit in digital watermark embedding apparatus of diagram according to the first embodiment is controlled embeds the operational flowchart of processing.

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

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

Figure 14 is the block diagram that the processing unit in the diagram digital watermark detecting device is the function of the digital watermark information realization on the detection video data.

Figure 15 A is the figure of an example changing of the time domain of the average pixel value of diagram reference zone.

Figure 15 B schematically illustrates by the frequency component for corresponding with triangular wave to carry out the figure that frequency inverse converts the time domain variation of the average pixel value obtained, wherein, change and to carry out extracting the frequency component corresponding with triangular wave in frequency spectrum that frequency transformation obtains from the time domain by illustrated average pixel value Figure 15 A.

Figure 16 A is the figure of another example of changing of the time domain of the average pixel value of diagram reference zone.

Figure 16 B is the figure of diagram for the frequency component in the cycle corresponding with each value of symbol, wherein, from by for each time period, the time domain of the average pixel value of illustrated reference zone Figure 16 A being changed the frequency component of carrying out extracting in frequency spectrum that frequency transformation obtains the cycle corresponding with each value of symbol.

Figure 16 C is the figure of diagram for the frequency component in the cycle corresponding with each value of symbol, wherein, from by for each time period, the time domain of the average pixel value of illustrated reference zone Figure 16 A being changed the frequency component of carrying out extracting in frequency spectrum that frequency transformation obtains the cycle corresponding with each value of symbol.

Figure 17 is the operational flowchart of diagram digital watermarking Check processing, and the computer program that this digital watermarking Check processing is carried out on the processing unit in digital watermark detecting device is controlled.

Embodiment

Digital watermark embedding apparatus is described below with reference to accompanying drawings.According to digital watermark embedding apparatus disclosed herein, the area of the watermark recovery formed by one group of pixel with particular value changes with time domain, makes thus the average pixel value in the zone of the watermark recovery that wherein superposes change 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.Frame refers to the complete still image comprised in video data, and field refers to the still image that the data in the row of row by only extract odd-numbered from frame or even-numbered form.

Fig. 1 is the figure illustrated in simplified form according to the configuration of the digital watermark embedding apparatus of an embodiment.Digital watermark embedding apparatus 1 comprises interface unit 11, storage unit 12 and processing unit 13.Digital watermark embedding apparatus 1 is embedded in the digital watermark information obtained via interface unit 11 to video data.

Interface unit 11 comprises: video signal interface, for digital watermark embedding apparatus 1 for example is connected to the dynamic image input media such as camcorder (not shown) or image display device such as liquid crystal display (not shown); And for the control circuit of video signal interface.Perhaps, interface unit 11 can comprise: communication interface meets the Ethernet such as Ethernet(, registered trademark for digital watermark embedding apparatus 1 is connected to) the communication network of communication standard; And for the control circuit of communication interface.In addition, or interface unit 11 is connected to digital watermark embedding apparatus 1 for receiving the antenna of the video data transmitted via wireless link, and comprises the circuit of being decoded for the video data to via antenna reception.

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

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

Digital watermark information comprises at least one identification number of selecting from following part: the identification number of spectators' identification number, video data provider and wherein comprise the identification number of the video playback apparatus of digital watermark embedding apparatus 1.In patent specification, using one of a plurality of numerals of identification number of the formation spectators that comprise in digital watermark information etc. or character such as a bit as symbol.Therefore, the symbol comprised in digital watermark information has one of a plurality of predetermined different values.For example, if the symbol comprised in digital watermark information is 1 bit, this symbol has value " 0 " or " 1 ".

Interface unit 11 receives the video data of embed digital watermarks from processing unit 13, and to image display device the video data such as liquid crystal display output embed digital watermark.Perhaps, interface unit 11 can send to other equipment that are connected to digital watermark embedding apparatus 1 via communication network the video data of embed digital watermark.

Storage unit 12 comprises at least one device for example be selected from semiconductor memory system, disk set and optical disc apparatus.The computer program that storage unit 12 storage will be carried out on digital watermark embedding apparatus 1 and the various parameters that will use for embed digital watermark information.In addition, digital watermark information and wherein also do not have one or more image comprised in the video data of embed digital watermark information temporarily to be stored in storage unit 12, until processing unit 13 has been set up the video data of embed digital watermark.Storage unit 12 can also be stored the video data that has wherein embedded digital watermark information.

Processing unit 13 comprises that one or more processors, memory circuitry are such as random access memory and their peripheral circuit.The integrated operation of processing unit 13 control figure watermark embedded equipments 1.

Processing unit 13 is embedded in digital watermark information as the watermark recovery with one group of pixel of particular value to video data by stack on each image in video data, wherein, the area of this watermark recovery changes in periodic mode in time according to the value of the symbol comprised in digital watermark information.

Fig. 2 is illustrated process unit 13 is the block diagram of the function that is embedded in digital watermark information to video data and realizes.Processing unit 13 comprises watermark recovery generation unit 21 and watermark recovery superpositing unit 22.These unit that form processing unit 13 are functional modules that on the processor by comprising in processing unit 13, computer program realizes.Perhaps, watermark recovery generation unit 21 and watermark recovery superpositing unit 22 can be respectively be arranged in digital watermark embedding apparatus 1 as function circuit independently.

Watermark recovery generation unit 21 generates the watermark recovery that will embed in each image according to the value of the symbol that will embed.In the present embodiment, watermark recovery is one group of one or more watermark block.Each watermark block comprises one or more pixels, and has for example rectangular shape.Perhaps, each watermark block can be circle, semicircle or triangle in shape.Each pixel comprised in watermark block has the particular value except " 0 ".In the present embodiment, this particular value is for the brightness value of respective pixel of the image of proofreading and correct on it watermark recovery that superposeed.Watermark recovery generation unit 21 increases or reduces the quantity of watermark block in time in periodic mode.When the quantity of watermark block increases, the area of watermark recovery increases.According to the value of the symbol that will embed, phase place or cycle that the periodicity time domain of the area of watermark recovery generation unit 21 change watermark recoveries changes.Result, the average pixel value that is defined in the reference zone that comprises the watermark recovery zone on whole image or in the part of image increases periodically in a similar fashion and reduces, thus phase place or cycle that the time domain of the average pixel value of periodic variation reference zone changes.

Fig. 3 is the figure that is shown in the example that the time domain of watermark recovery on one-period changes.In illustrated example, each pixel in each watermark block comprised in watermark recovery have 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 pixel that stack comprises in watermark recovery, the value of the pixel of stack becomes and is greater than original pixel value.

Fig. 3 illustrates 9 images that time domain is continuous of from time t to the time (t+8).Rectangle watermark recovery 311 is superimposed upon on image 301 at time t place.Then, along with the quantity of watermark block 312, from time t to the time, time interval of (t+4) reduces, the area that is superimposed upon the watermark recovery on image reduces.Then, in the time (t+4), locate to reduce watermark recovery from image 302.After the time (t+4), the area of watermark recovery starts to increase, until the maximal value of the area of watermark recovery in locating to reach again image 303 in the time (t+8).

Fig. 4 be shown in watermark recovery with the graph of a relation corresponding with Fig. 3 area over time and the figure of the curve map of the relation of the average pixel value in reference area between over time.In the upper curve figure of Fig. 4, horizontal ordinate means the time, and ordinate means the area of watermark recovery.How the area that curve map 401 illustrates watermark recovery is changing time interval of (t+8) from time t to the time.On the other hand, in lower curve figure, horizontal ordinate means the time, and ordinate means pixel value.How the average pixel value that curve map 402 illustrates reference zone is changing time interval of (t+8) from time t to the time.For ease of understanding, suppose in each image to as if fixing.

As shown in curve map 401, the area of watermark recovery mode with triangular wave on time interval of (t+8) from time t to the time changes.As mentioned above, in shown example, each pixel in watermark recovery have on the occasion of.As a result, as shown in curve map 402, the average pixel value of reference zone reduces with the area of watermark recovery and reduces, and increases with the area of watermark recovery.Therefore, average brightness value also changes with time domain in the mode of triangular wave, and the phase place of the triangular wave of the variation of expression average pixel value is identical with the phase place of the triangular wave of the variation of the area that means watermark recovery.

Fig. 5 is the figure that illustrates another example of the time domain change of watermark recovery on one-period.In illustrated example, each pixel comprised in watermark recovery have negative value such as " 2 " as particular value.Therefore, each watermark block shows itself with the form of shaded block; As a result, when pixel that stack comprises in watermark recovery, the value of the pixel of stack becomes and is less than original pixel value.

Fig. 5 illustrates 9 images that time domain is continuous of from time t to the time (t+8).Be in superimpose rectangles watermark recovery 511 on image 501 at time t.Then, when the quantity of watermark block 512, when from time t to the time, time interval of (t+4) reduces, the area that is superimposed upon the watermark recovery on image reduces.Then, in the time (t+4), locate to reduce watermark recovery from image 502.After the time (t+4), the area of watermark recovery starts to increase, until the maximal value of the area of watermark recovery in locating to reach again image 503 in the time (t+8).

Fig. 6 be with the graph of a relation corresponding with Fig. 5 be shown in watermark recovery area over time and the figure of the curve map of the relation of the average pixel value in the zone that comprises watermark recovery between over time.In the upper curve figure of Fig. 6, horizontal ordinate means the time, and ordinate means the area of watermark recovery.How the area that curve map 601 illustrates watermark recovery is changing time interval of (t+8) from time t to the time.On the other hand, in lower curve figure, horizontal ordinate means the time, and ordinate means pixel value.How the average pixel value that curve map 602 means reference zones is changing time interval of (t+8) from time t to the time.

As shown in curve map 601, the area of watermark recovery mode with triangular wave on time interval of (t+8) from time t to the time changes.In illustrated example, each pixel in watermark recovery has negative value.As a result, as shown in curve map 602, the average pixel value of reference zone reduces with the area of watermark recovery and increases, and increases and reduce with the area of watermark recovery.Therefore, average pixel value also changes in the triangular wave mode in time, and the phase place of the triangular wave of the variation of expression average pixel value is with respect to the single spin-echo of the triangular wave of the variation of the area that means watermark recovery.

Fig. 7 is the figure of another example of changing of the time domain of diagram watermark recovery.In illustrated example, each pixel in each watermark block comprised in watermark recovery have value such as " 2 " or " 2 " as particular value.Yet, also, in this example, determine and will be superimposed upon the watermark recovery on each image, so that the average pixel value of reference zone is with the mode time to time change of triangular wave, just as the situation at illustrated watermark recovery in Fig. 5.

Fig. 7 illustrates 9 images that time domain is continuous of from time t to the time (t+8).At time t place, superimpose rectangles watermark recovery 711 on image 701.Each pixel comprised in watermark recovery 711 has negative value, thereby whole watermark recovery 711 shows itself with the form of hatching pattern.Then, have on the occasion of the quantity of luminous point shape watermark block 713 with the ratio of the quantity of the shade watermark block 712 with negative value, on time interval of (t+4) from time t to the time, increase gradually.Then, in the image 702 of locating in the time (t+4), whole watermark recovery 711 shows itself with the form of luminous point shape pattern.As a result, the average pixel value of reference zone is from time t to the time, time interval of (t+4) increases.After the time (t+4), have on the occasion of the quantity of luminous point shape watermark block 713 with the ratio with shade watermark block 712 of negative value, reduce gradually, until whole watermark recovery was located again to show itself with the form of the hatching pattern in image 703 in the time (t+8).

As mentioned above, as example, the value of the symbol that the phase place changed by reference to the time domain of the average pixel value in zone indicates to embed in video data.In this case, watermark recovery generation unit 21 is for example for wherein comprising a plurality of images and wherein embedding the area that the first image comprised in the fixed time section of a symbol is determined watermark recovery.Then, for second and the follow-up image that comprise in this time period, watermark recovery generation unit 21 is determined the area of the watermark recovery that will superpose on each image, so that the average pixel value of reference zone is with triangular wave mode temporal evolution.Then, the area of the watermark recovery of watermark recovery generation unit 21 by will be definite for this image, divided by the area of a watermark block, is determined the quantity that will be superimposed upon the watermark block comprised in the watermark recovery on interested image.The fixed time section is chosen as to one times or the several times in the cycle that the time domain of the area that for example equals watermark recovery changes.

Watermark recovery generation unit 21 is determined will be superimposed upon the watermark recovery on interested image so that the shape of this watermark recovery with closely follow the image of interested image on the shape of the watermark recovery that superposes different.In this case, preferably, determine that the shape of watermark recovery is not so that one of two watermark recoveries on being superimposed upon respectively the continuous image of two time domains are included in another of pattern.For example, as shown in Fig. 3,5 and 7, preferably, watermark recovery generation unit 21 is determined the layout that will be superimposed upon the watermark block on interested image, so that this is arranged with uncorrelated with the layout of the watermark block in image afterwards before interested image.This makes the watermark recovery be superimposed upon on each image be not easy to be felt by spectators, because the position of watermark block passes by change randomly in time.

Further preferably, watermark recovery generation unit 21 is determined the layout of each watermark block, so that the area of the watermark block comprised in any specific part in watermark recovery zone when the area of watermark recovery becomes maximum also changes in time in the triangular wave mode.Even this makes digital watermark detecting device described later also can detect the variation of the area of watermark recovery when only paying close attention to watermark recovery zone a part of.

For example, when the area of watermark recovery becomes maximum, the zone of the watermark recovery that wherein superposes is divided into N sub-block (N is not less than 2 integer), and the area of each sub-block is not less than the area of a watermark block.Each sub-block is pressed grating (raster) scanning sequency with the ascending order serial number, for example, and since 1 and finish at the N place.Then, watermark recovery generation unit 21 determines by the value of obtaining k element in random series the quantity that wherein will place the sub-block of each watermark block, wherein, each of the element of random series is all exported value in the scope that drops on 1 to N (at this, 1≤k≤m, wherein, m indicates to be superimposed upon the sum of the watermark block on interested image, and is defined as m≤N).The different random sequence that is used for different images by use, watermark recovery generation unit 21 can be determined the layout of the watermark block that will superpose on interested image, makes the layout of this layout and the watermark block in the image of interested image front and rear uncorrelated.

Perhaps, can be in advance in storage unit 12 for the one or more watermark recoveries of each watermark recovery area stores, in these watermark recoveries, the layout of watermark block differs from one another.Then, from the watermark recovery of the area corresponding to being superimposed upon the watermark recovery interested image, watermark recovery generation unit 21 can be for example according to specified order or by select a watermark recovery by random series.Specified order herein is for example ascending order or the descending to the numbering of watermark recovery distribution.

In addition, or watermark recovery generation unit 21 can pass through to use the method except as mentioned above, next definite shape that will be superimposed upon the watermark recovery on each image.

Fig. 8 is the figure that is shown in an example of the relation between the value of the time in the past of watermark recovery and insertion symbol.In the upper and lower curve map of Fig. 8, horizontal ordinate means the time, and ordinate means the average pixel value of reference zone.The average pixel value that curve map 801 and 802 illustrates reference zone when value of symbol is respectively " 0 " or " 1 " is temporal evolution how.

In illustrated example, when value of symbol is " 0 ", average pixel value is minimum (secretly) at start time t0 place, and in the mode of triangular wave, change into thereafter brightly, then changes into secretly, then changes into bright.On the other hand, when value of symbol is " 1 ", average pixel value is maximum (bright) at start time t0 place, and in the mode of triangular wave, change into secretly thereafter, then changes into brightly, then changes into secretly.By this way, the time domain variation that the time domain of the average pixel value when value of symbol is " 0 " changes the average pixel value when when value of symbol, being " 1 " differs 180 ° on phase place.

If watermark recovery comprises the shade watermark block, when the area of watermark recovery, hour average pixel value is the highest.Therefore, when average pixel value from bright to secretly and then to bright change the time, the area of watermark recovery by this order from minimum to maximum then to minimum change.On the contrary, if watermark recovery comprises luminous point shape watermark block, when the area of watermark recovery is maximum, average pixel value is the highest.Therefore, when average pixel value from bright to secretly and then to bright change the time, then the area of watermark recovery changes to maximum from maximum to minimum by this order.

Not necessarily will make the phase differential between changing and change for the time domain of another value of symbol average pixel value for the time domain of a value of symbol average pixel value equal 180 °, but only need to make, this phase differential is large must be enough to make digital watermark detecting device this phase differential can be detected.

Fig. 9 is the figure that is shown in another example of the relation between the value of the time in the past of watermark recovery and insertion symbol.In the upper and lower curve map of Fig. 9, horizontal ordinate means the time, and ordinate means the average pixel value of reference zone.The average pixel value of reference zone temporal evolution how when curve map 901 and 902 illustrates respectively phase differential between the time domain of the average pixel value for a value of symbol reference zone changes and changes for the time domain of the average pixel value of another value of symbol reference zone and is 180 °.Each double-headed arrow 910 parallel with the horizontal ordinate cardinal principle means and the time periods that symbol is corresponding, and the value of symbol of the numeric representation under each arrow in this time period.

Border 921 and 922 places that curve map 901 changes between " 0 " and " 1 " at symbol demonstrate large gap.In view of this point, by for each of symbol " 0 " and " 1 ", by 90 ° of the phase-shifts of triangular wave, as shown in curve map 902, watermark recovery generation unit 21 can be so that change on the border 923 and 924 that average pixel value changes at value of symbol smoothly.Thereby, watermark recovery generation unit 21 can so that the change spectators of value of symbol be not easy to feel.In curve map 902, the phase differential between the triangular wave for symbol " 0 " and " 1 " remains on 180 ° equally.

Perhaps, can change according to value of symbol cycle of variation of the area of watermark recovery, the i.e. cycle of the variation of average pixel value in reference zone.

Figure 10 is the figure that is shown in another example of the relation between the value of the time in the past of watermark recovery and insertion symbol.Figure 10 upper, in and in lower curve figure, horizontal ordinate means the time, ordinate means the average pixel value of reference zone.The average pixel value that curve map 1001 and 1002 illustrates reference zone when value of symbol is respectively " 0 " or " 1 " is temporal evolution how.In illustrated example, for the cycle T 1 of value of symbol " 1 ", be half for the cycle T 2 of value of symbol " 0 ".Therefore, if suppose that cycle T 2 is by example 8 image constructions as shown in Figure 3, cycle T 1 is by four image constructions.In this example, preferably, make the length of the time period that wherein embeds each symbol identical equally, and irrelevant with value of symbol, in order to facilitate the detection of embedding value.For example, as shown in the curve Figure 103 changing by the time domain illustrated for the average pixel value of a plurality of symbol reference zones in Figure 10, when value of symbol is " 0 ", two cycles of each time period 1010 by the variation of average pixel value form; On the other hand, when value of symbol is " 1 ", four cycles of each time period 1010 by the variation of average pixel value form.

Watermark recovery generation unit 21 will be definite for each image watermark recovery be sent to watermark recovery superpositing unit 22.

22 identifications of watermark recovery superpositing unit are for the reference zone of each image.Then, watermark recovery superpositing unit 22, by the value of the respective pixel that comprises in the specific watermark piece that uses the watermark recovery in reference zone, is proofreaied and correct the value of each pixel comprised in the zone overlapping with this watermark block.For example, if each pixel comprised in this watermark block has value " 2 ", watermark recovery superpositing unit 22 from the overlapping zone of watermark block the value of each pixel of comprising deduct " 2 ".On the contrary, if each pixel comprised in watermark block has value " 2 ", watermark recovery superpositing unit 22 to the overlapping zone of watermark block in the value of each pixel of comprising add " 2 ".

As mentioned above, watermark recovery superpositing unit 22 can, along the seasonal effect in time series direction, embed a plurality of symbols in video data.In this case, each time period corresponding with the symbol embedded in video data finishes, and can on image, superpose and be used for meaning the given pattern of character boundary, and it is lasting until start corresponding to time period of next symbol.

Watermark recovery superpositing unit 22 is stored the image that is superimposed with watermark recovery on it in storage unit 12.Perhaps, watermark recovery superpositing unit 22 can be exported on it via interface unit 11 image that is superimposed with watermark recovery to another equipment.

Figure 11 is that the digital watermarking that the computer program carried out on the processing unit of diagram in the digital watermark embedding apparatus according to the present embodiment is controlled embeds the operational flowchart of processing.Processing unit 13 is carried out following digital watermarking for each symbol comprised in digital watermark information and is embedded processing.

Select interested symbol (step S101) in the symbol that processing unit 13 comprises from the digital watermark information received via interface unit 11.Then, the watermark recovery generation unit 21 in processing unit 13 arranges the fixed time section in video data, and this fixed time section comprises a plurality of images (step S102) that wherein will embed interested symbol.

Select interested image (step S103) in a plurality of images that watermark recovery generation unit 21 comprises in chronological order from the fixed time section.Then, watermark recovery generation unit 21 is determined the area that will be superimposed upon the watermark recovery on interested image, so that phase place or the cycle temporal evolution (step S104) of the average pixel value of reference zone to mate interested value.Watermark recovery generation unit 21 is determined the quantity of the watermark block that will comprise in watermark recovery according to the area of watermark recovery.In addition, watermark recovery generation unit 21 is identified for the layout of the watermark block of interested image so that for the watermark recovery of interested image in shape from the watermark recovery different (step S105) of image for immediately following it.Then, watermark recovery 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, is proofreaied and correct the value (step S106) of each pixel comprised in the zone overlapping with this watermark block.

Thereafter, processing unit 13 determines whether the fixed time section finishes (step S107).If the fixed time section does not also finish (in step S107 no), the processing that processing unit 13 repeats from step S103 to step S107.On the other hand, if the fixed time section finishes (in step S107 be), processing unit 13 continues next symbol to comprising in digital watermark information and carries out watermark and embed and process.The number of times that symbol lengths and symbol embed is scheduled to, and processing unit 13 repeats to embed and processes, until reach pre-determined number.Perhaps, processing unit 13 can repeat to embed and process, until so much symbol that the length of embedding and dynamic image allows.

As mentioned above, digital watermark embedding apparatus according to the present embodiment, the area that is superimposed upon the watermark recovery on image periodically changes, and changes periodically thus the average pixel value of reference zone, the value that the cycle that the time domain of average pixel value changes or phase place mean insertion symbol.The value of each pixel that as a result, digital watermark embedding apparatus comprises in can watermark recovery is set to little constant value.Therefore, digital watermark embedding apparatus not only can independently minimize with the image that comprises in video data because the watermark information embedded in video data causes the decline of the image quality of the video data that may occur, and can be so that spectators are difficult to visually identify the digital watermarking of embedding.In addition, because make the shape of the watermark recovery that must superpose different in order to prevent that watermark recovery always is superimposed upon on same specific region, so digital watermark embedding apparatus can be so that spectators more be difficult to visually identify the digital watermarking of embedding for each image.

Digital watermark embedding apparatus can determine whether to embed digital watermark information by following manner: whether the average pixel value that only from the video data of embed digital watermark information wherein, detects reference zone periodic variation.As a result, if take to copy the wherein video data of embed digital watermark information by simulation, as long as remaining on digital watermark information in the image of the video data copied, reference zone just keeps complete.

According to another embodiment, digital watermark embedding apparatus can be embedded in a plurality of symbols that comprise in digital watermark information to each image in video data.In this case, for a plurality of reference zones of each image setting in video data and will be included in a plurality of watermark recoveries in each reference zone.In each reference zone and this reference zone, the watermark recovery of stack is corresponding to a symbol.In addition, if the whole symbols that comprise in digital watermark information will be embedded in each image, the fixed time section can be set and start for the first image place in video data, and finish at last image place.

The time domain variation of the area of watermark recovery is not limited to the triangle wave change.According to an alternate embodiment, the watermark recovery generation unit can be determined the area that will be superimposed upon the watermark recovery on each image, so that the specific frequency components that the time domain of the area of watermark recovery changes has the reinforcement value.For example, the watermark recovery generation unit can be determined the area that will be superimposed upon the watermark recovery on each 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, for example, by reference to the phase place of the variation of regional average pixel value and the value that a symbol is determined in the combination in cycle.For example, the phase place that maximizes the average pixel value of the reference zone in the first image comprised in section the preset time wherein embed a symbol is designated as " just ", and the phase place that minimizes the average pixel value of the reference zone in the first image comprised in this time period is designated as " bearing ".In addition, when the time domain variation of average pixel value has the period 1, the time domain variation is designated as " short ", and, when the time domain variation of average pixel value has than the second round of period 1 length, the time domain variation is designated as " length ".At this, suppose that the symbol in one-period can have one of four probable values " 0 ", " 1 ", " 2 " and " 3 ".In this case, the watermark recovery generation unit is for example 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 a bit and digital watermark information while being meaned by bit sequence, the processing unit in digital watermark embedding apparatus can be by coming to bit sequence application Error Correction of Coding by error correcting code or error-detecging code.Then, processing unit can be embedded in to video data the symbol pattern of Error Correction of Coding.For example, processing unit can be used the example of cyclic redundancy check (CRC) code (CRC) as error correcting code.In this case, processing unit can be converted to the bit sequence comprised in digital watermark information the CRC code, and is embedded in the CRC code to video data.Only need to make the average pixel value of reference zone differently to change according to the value of symbol embedded.When embedding the symbol of a plurality of CRC codings in each image, digital watermark detecting device can be determined the value of each insertion symbol, and needn't understand phase place that the time domain for the average pixel value of the reference zone of this symbol changes or the relation between cycle and this value of symbol.Digital watermark detecting device determines that the embedding value is divided by drawing the value of remainder " 0 " when generating the same generator polynomial of CRC code when the bit sequence extracted from video data.

For example, if suppose that this generator polynomial as divisor is to comprise sequence " 111011 " in " 1011 " and digital watermark information, the CRC code corresponding with this bit sequence is given " 1110011010 ".

In this case, from the video data of embed digital watermark information wherein, digital watermark detecting device obtains phase place or cycle of time domain variation of the average pixel value of the reference zone corresponding with each bit.Then, digital watermark detecting device obtains two bit sequences " 1110011010 " and " 0001100101 " by the phase place to different or the different value of symbol of period allocated.Next, in order to determine that the bit sequence extract is " 1110011010 " or " 0001100101 " from video data, digital watermark detecting device by each of two bit sequences divided by divisor " 1011 ".Then, digital watermark detecting device can determine that " 1110011010 " that draw remainder " 0 " are to embed bit sequence, and, by remove check bit " 010 " from this bit sequence, can obtain the bit sequence of embedding.

According to another modified example, the digital watermark embedding apparatus embed digital watermark information, so that digital watermark detecting device can be identified the phase place that the periodicity time domain of the average pixel value of the reference zone corresponding with the value of symbol embedded in each image changes.For this purpose, digital watermark embedding apparatus can be for a plurality of reference zones of each image setting, and can be set to particular reference region with reference to one of zone.Then, the watermark recovery generation unit in processing unit is identified for the watermark recovery of particular reference region, so that the average pixel value of particular reference region always changes with the constant cycle.Below watermark recovery for the particular reference region setting, be called as " reference pattern ".

The watermark recovery generation unit is determined watermark recovery, so that be assigned with the time domain of average pixel value of any other reference zone of insertion symbol, change and also will have the cycle identical with reference pattern.In addition, the watermark recovery generation unit is according to the value of the symbol embedded, and determines that time domain at the area of watermark recovery changes and the time domain of the area of reference pattern changes, is that the time domain of the average pixel value of reference zone changes and the time domain of the average pixel value of the particular reference region phase differential between changing.For example, when value of symbol is " 0 ", watermark recovery generation unit generating watermark pattern, so that wherein embed the phase place that the time domain of the average pixel value of the phase matching particular reference region that the time domain of average pixel value of the reference zone of this symbol changes changes.On the other hand, when value of symbol is " 1 ", watermark recovery generation unit generating watermark pattern, so that wherein embed 90 ° or 180 ° of the phase-shifts that phase place that the time domain of average pixel value of the reference zone of this symbol changes changes with respect to the time domain of the average pixel value of particular reference region.

According to another modified example, can make stipulations so that the watermark recovery generation unit is not used the watermark recovery of the shape overlapping with whole reference zone.

How in time Figure 12 is diagram when making regulation watermark recovery figure of an example of change when not using the watermark recovery of the shape overlapping with whole reference zone.In illustrated example, each pixel comprised in watermark recovery have negative value such as " 2 " as particular value.

Figure 12 illustrates 7 images that time domain is continuous of from time t to the time (t+6).Have maximum area watermark recovery 1211, be that the watermark block 1212 of maximum quantity is superimposed upon on image 1201 at time t place.Then, from time t to the time (t+3), the area of watermark recovery reduces, but, after the time (t+3), the area of watermark recovery increases.Then, the area of watermark recovery was located to become maximum again in image 1202 in the time (t+6).In illustrated example, any one of the watermark recovery superposeed on each image 1201 and 1202 is not rectangular shape, but arranges a plurality of watermark block spacedly.

By this way, preferably, even determine watermark recovery so that in the situation that have the watermark recovery of the watermark block of maximum quantity, watermark recovery also not exclusively overlaps with reference zone, and is set to and is shorter than set-point at the outer nose of placing of watermark recovery.By watermark recovery so is set, even in the situation that have the image of the background of uniform luminance such as sky, the border in the zone of the watermark recovery that superposeed on it also becomes and is not easy to be felt.Therefore, digital watermark embedding apparatus can further reduce because the watermark recovery embedded causes the decline of the image quality of the video data that may occur.Determine this set-point by experience, and arrange to such an extent that equal for example to have 1/2nd to 1/3rd of the width of watermark recovery of maximum area or height by this set-point.

Next, the description of the digital watermark detecting device that detects the digital watermark information that the digital watermark embedding apparatus by the embodiment according to top or its modified example embeds in video data will be provided.

Figure 13 is the figure illustrated in simplified form according to the configuration of the digital watermark detecting device of an embodiment.Digital watermark detecting device 2 comprises interface unit 31, storage unit 32 and processing unit 33.Digital watermark detecting device 2 detects the digital watermark information embedded in the video data obtained via interface unit 31.

Interface unit 31 comprises: video signal interface, for digital watermark detecting device 2 for example being connected to the dynamic image input media such as camcorder (not shown); And for the control circuit of video signal interface.Perhaps, interface unit 31 can comprise: communication interface meets the Ethernet such as Ethernet(, registered trademark for digital watermark detecting device 2 is connected to) the communication network of communication standard; And for the control circuit of communication interface.

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

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

Storage unit 32 comprises at least one device that for example is selected from semiconductor memory system, disk set and optical disc apparatus.Storage unit 32 is stored the computer program that will carry out on digital watermark detecting device 2 and will be used so that the various parameters of the digital watermark information embedded in detecting video data.For example, storage unit 32 is stored in position and scope and the mapping table of the reference zone limited on image, and this mapping table is provided at phase place that the time domain of the average pixel value of embedding value and reference zone changes or the mapping between the cycle.Storage unit 32 can also be stored detected digital watermark information, and storage unit 32 can also be stored the video data that has wherein embedded digital watermark information.

Processing unit 33 comprises that one or more processors, memory circuitry are such as random access memory and their peripheral circuit.Processing unit 33 detects the digital watermark information embedded in video data.In addition, the integrated operation of processing unit 33 control figure watermark detection equipment 2.

Figure 14 is the block diagram of illustrated process unit for the function of the digital watermark information realization on the detection video data.

Processing unit 33 comprises average pixel value computing unit 41, frequency conversion unit 42 and watermark information extraction unit 43.Processing unit 33 via interface unit 31 from the camcorder of taking the video data of embed digital watermark information wherein or obtain video data from certain other equipment of stored video data.Then, processing unit 33 detects the digital watermark information of embedding by analyzing this video data.

Average pixel value computing unit 41 is received in from processing unit 33 image comprised the video data of embed digital watermark information wherein by the time sequence order.Then, average pixel value computing unit 41 calculates average pixel value for the reference zone in each image.If for a plurality of reference zones of each image setting, average pixel value computing unit 41 calculates average pixel value for each reference zone.

If video data is the video by not only taking embed digital watermark information wherein but also takes the video that simulation that background on original video etc. obtains is taken, average pixel value computing unit 41 can be from all simulation capture video calculating average pixel values.Perhaps, average pixel value computing unit 41 can, by each image applications rim detection, detect the dynamic image zone that comprises original video.In this case, the reference zone that average pixel value computing unit 41 detects in the dynamic image zone.In addition, in this case, average pixel value computing unit 41 is by for example being used Sobel (Sobel) wave filter or Laplce (Laplacian) wave filter to detect the edge on each image.Then, average pixel value computing unit 41 determines in the edge substantially extended in the horizontal direction, the coboundary in the dynamic image zone that for example the longest edge edge in the first half of image means to comprise original video.Equally, average pixel value computing unit 41 determines that for example the longest edge edge in the latter half of image means the lower limb in dynamic image zone in the limit of substantially extending in the horizontal direction.In addition, average pixel value computing unit 41 is determined in the edge substantially extended in vertical direction, for example the longest edge edge in the left-half of image means the left hand edge in dynamic image zone, and the longest edge edge in the right half part of image means the right hand edge in dynamic image zone.If the length of the longest edge edge substantially extended in the horizontal direction in the first half of image be for example image horizontal width half or less, average pixel value computing unit 41 can be determined the coboundary of the coboundary of image corresponding to the dynamic image zone.In addition, if the length of the longest edge edge extended on horizontal direction in the latter half of image substantially be for example image horizontal width half or less, average pixel value computing unit 41 can be determined the lower limb of the lower limb of image corresponding to the dynamic image zone.Equally, if the length of the longest edge edge substantially extended in vertical direction in the left-half of image or right half part be for example image vertical height half or less, average pixel value computing unit 41 can be determined the left hand edge of image or left hand edge or the right hand edge that right hand edge corresponds respectively to the dynamic image zone.

Average pixel value computing unit 41 is determined the coboundary of reference zones so that the distance between the coboundary of the coboundary in dynamic image zone and reference zone and the ratio of the height in dynamic image zone become with the original video of simulating shooting in corresponding ratio identical.Equally, average pixel value computing unit 41 can be determined any other edge of reference zone so that the distance between the corresponding edge of dynamic image zone and reference zone and the ratio of the height in dynamic image zone or width become with original video in corresponding ratio identical.

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

Frequency conversion unit 42 is set up one-dimensional vector by being disposed in order with time series for each reference zone or for the average pixel value of whole image.Then, by the one-dimensional vector of each time period to corresponding with value of symbol, carry out frequency transformation, frequency conversion unit 42 obtains the frequency spectrum that the time domain of the average pixel value for meaning this time period changes.For example use fast fourier transform or discrete cosine transform to carry out frequency transformation.Frequency conversion unit 42 can be identified each time period by the given pattern of using the technology for detection of pattern match for example to be used to indicate the time period border.

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

Based on for each reference zone or the frequency spectrum that obtains for whole image, change for the time domain meaned for the average pixel value of each time period, watermark information extraction unit 43 extracts and is embedded in the digital watermark information in video data.

The average pixel value of reference zone also changes in time, unless the video of wherein taking in the image of embed digital watermark information is still image.

Figure 15 A is the figure of an example changing of the time domain of the average pixel value of diagram reference zone.In Figure 15 A, horizontal ordinate means the time, and ordinate means pixel value.Curve map 1501 in Figure 15 A be described in pass by time in reference zone image modification the time reference zone the how time dependent example of average pixel value.Exist variation on the average pixel value of reference zone wherein mainly owing to the situation of the variation of the area of the image in reference zone rather than watermark recovery.Under these circumstances, as found out from curve map 1501, be difficult to from the change component of the time domain variation average pixel value that directly extraction is associated with the variation of the area of watermark recovery of average pixel value.

Yet, become known in advance meaning because the frequency that the time domain of the average pixel value of the reference zone that the variation of the area of watermark recovery causes changes.For example, when the average pixel value of reference zone during with triangular wave mode temporal evolution, as previously mentioned, along the frequency of the average pixel value of time-axis direction, comprise the frequency component corresponding to triangular wave.

Figure 15 B schematically illustrates the figure that the time domain by the following frequency component corresponding with triangular wave being carried out to the average pixel value that the frequency inverse conversion obtains changes: this frequency component is extracted from the frequency spectrum of frequency transformation acquisition is carried out in the time domain variation of the average pixel value by describing Figure 15 A.In Figure 15 B, horizontal ordinate means the time, and ordinate means pixel value.The time domain that curve map 1502 in Figure 15 B has been described the pixel value by only obtaining to the conversion of the frequency component application frequency inverse corresponding to triangular wave changes.As found out from curve map 1502, by only extracting because the frequency component that the variation of the area of watermark recovery causes only extract because the periodicity time domain change component of the average pixel value of the reference zone that the variation of the area of watermark recovery causes.While when the video that the simulation from comprising background etc. is taken, detecting watermark recovery, watermark information extraction unit 43 is not only used reference zone, and uses and comprise the whole image of noise ratio as background; If the cycle of the variation of the area of watermark recovery is different from background, can detected symbol.

In view of this point, watermark information extraction unit 43 is from for each reference zone or the frequency spectrum that obtains for each for whole image time period, only extracts with the time domain of the periodically variable average pixel value of the area that is associated with watermark recovery and changes corresponding frequency component.Then, when the phase place of the variation of the time domain by average pixel value means the value of insertion symbol, watermark information extraction unit 43 obtains phase information from the frequency component of extracting.Then, watermark information extraction unit 43 for example is used for providing the mapping table of the mapping between phase place and value of symbol by reference, obtain the value of symbol corresponding to this phase place.

Perhaps, can be changed by the time domain of the average pixel value of reference zone and the time domain of the average pixel value of the particular reference region phase differential between changing is determined value of symbol, as mentioned above.In this case, the frequency component of watermark information extraction unit 43 from being associated with the variation of the area of watermark recovery for extraction the frequency spectrum of reference zone and particular reference region respectively.Then, watermark information extraction unit 43 obtains respectively the phase place of the frequency component of extracting for reference zone and particular reference region, and poor between the phase place in the computing reference zone and the phase place in particular reference region.Watermark information extraction unit 43 provides the mapping table of the mapping between phase differential and value of symbol from storage unit 32 retrievals.Watermark information extraction unit 43 is with reference to mapping table, and determines that the value of symbol corresponding to detected phase differential is the value of insertion symbol.

Perhaps, if being embedded in the bit sequence of the digital watermark information of video data for expression is the Error Correction of Coding of using the CRC code, watermark information extraction unit 43 is according to the possible symbol pattern of each reference zone of phase calculation of the time domain variation of the average pixel value for each time period.For example, if symbol is a bit, supposing in the situation that the symbol of each time period is respectively " 0 " or " 1 " for identical phase place, watermark information extraction unit 43 is set up two patterns.Then, watermark information extraction unit 43 is selected to be judged as faultless symbol pattern by CRC check.For example, when the phase place in three time periods is different, be respectively for example 0 °, 180 ° and 0 °, possible symbol pattern is (0,1,0) and (1,0,1).As mentioned above, also can by embedding in advance the CRC Parity Check Bits, as watermark symbol and by carry out the CRC parity checking when carrying out symbol decision, to carry out about which pattern be determining of correct symbol pattern.

On the other hand, when the cycle that the time domain of the area by digital watermarking changes means value of symbol, watermark information extraction unit 43 obtains the strongest frequency component in the frequency component of the probable value that can adopt corresponding to this symbol, and obtains corresponding to cycle of strong frequency component.

Figure 16 A is the figure of another example of changing of the time domain of the average pixel value of diagram reference zone.In Figure 16 A, horizontal ordinate means the time, and ordinate means pixel value.Curve map 1601 in Figure 16 A described pass by time in reference zone image modification the time reference zone the how time dependent example of average pixel value.Double-headed arrow 1602 and 1603 means wherein to embed respectively the time period of a symbol.As found out from curve map 1601, be difficult to the cycle of the variation of the average pixel value that detection is associated with the variation of the area of watermark recovery in each time period.

Figure 16 B and 16C be diagram from by for each time period to the time domain of the average pixel value of illustrated reference zone Figure 16 A change carry out extracting in frequency spectrum that frequency transformation obtains, for the figure of the frequency component in the cycle corresponding to each value of symbol.In Figure 16 B and 16C, horizontal ordinate means the frequency component of extracting, and ordinate means the intensity of frequency spectrum.Figure 16 B 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 comprises specific to triangle a plurality of frequency components of wave period.

As shown in Figure 16 B, in the time period 1602, corresponding to the intensity of the frequency component 1611 of cycle T 1, be greater than the intensity corresponding to the frequency component 1612 of cycle T 2.As a result, the cycle of the variation of the area of watermark information extraction unit 43 deduction watermark recoveries is T1.On the other hand, as shown in Figure 16 C, in the time period 1603, corresponding to the intensity of the frequency component 1622 of cycle T 2, be greater than the intensity corresponding to the frequency component 1621 of cycle T 1.As a result, the cycle of the variation of the area of watermark information extraction unit 43 deduction watermark recoveries is T2.

Watermark information extraction unit 43 is provided at the mapping table of the mapping between cycle and value of symbol from storage unit 32 retrievals.Watermark information extraction unit 43 is with reference to mapping table, and determines that the value of symbol corresponding to the detected cycle is the value of insertion symbol.

Watermark information extraction unit 43 carrys out the reconstructing digital watermark information by with time series, being disposed in order the value of symbol extracted.If for a plurality of reference zones of each image setting, and insertion symbol in each reference zone, watermark information extraction unit 43 by with wherein in image the value of symbol be disposed in order for each reference zone of insertion symbol carry out the reconstructing digital watermark information.

Figure 17 is the operational flowchart of the digital watermarking Check processing controlled of the computer program carried out on the processing unit 33 of diagram in digital watermark detecting device 2.Processing unit 33 is carried out following processing for each symbol comprised in the digital watermark information embedded in video data.

Processing unit 33 is selected a plurality of images (step 201) that comprise in the fixed time section corresponding to a symbol in video data.Average pixel value computing unit 41 in processing unit 33 for the image calculation of each selection for reference zone or for the average pixel value (step 202) of whole image.Then, average pixel value computing unit 41 transmits average pixel value to frequency conversion unit 42.

Frequency conversion unit 42 calculates by following manner the frequency spectrum that the time domain of average pixel value changes: for each time period to by be disposed in order the one-dimensional vector that average pixel value sets up with time series, carrying out frequency transformation (step S203).Then, frequency conversion unit 42 transmits frequency spectrum to watermark information extraction unit 43.

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

Processing unit 33 repeats digital watermark detection process to obtain next symbol.After the symbol that has extracted predetermined quantity, processing unit 33 end number watermark detection process.

If for a plurality of reference zones of each image setting, processing unit 33 is for each reference zone repeating step S202 to S206.

As mentioned above, can from the video data of the digital watermark embedding apparatus embed digital watermark information by according to previous embodiment, extract digital watermark information according to the digital watermark detecting device of the present embodiment.In addition, even when taking the video data of embed digital watermark information wherein by simulation means, phase place or cycle that the time domain of the area of watermark recovery changes do not change yet.Therefore, the video data that digital watermark detecting device even can be taken from such simulation, extract digital watermark information.

Video data by the digital watermark embedding apparatus embed digital watermark information can be color image data.For example, if video data has the monochrome information for each of three kinds of color redness (R), green (G) and blue (B), according to the digital watermark embedding apparatus of embodiment can for one of three kinds of colors or two or carry out top digital watermarking for all three kinds of colors and embed processing.Perhaps, digital watermark embedding apparatus can or be carried out top digital watermarking for saturation degree, colourity etc. for brightness or tone component and embed processing.On the other hand, digital watermark detecting device can be carried out top digital watermarking Check processing for one or more colors of embed digital watermark information.

According to the digital watermark embedding apparatus of top embodiment, for example be comprised in Set Top Box, server or personal computer.Be equipped with the equipment of digital watermark embedding apparatus when playing video data, for video data, via the video content of communication network or antenna reception, carry out top digital watermarking and embed and process.If video data is that this equipment is decoded to each image in video data according to the compression scheme of appointment by the data of the compression scheme compression of appointment.Then, this equipment will be stored in from the image of video data decoding in its memory buffer with the time series order.Next, this equipment is retrieved each image from memory buffer with the time series order, and the combine digital watermark embeds to be processed, and makes display unit show the image of embed digital watermark information.

In addition, can be provided for making the computer program of computer realization according to each function of the processing unit in the digital watermark embedding apparatus of top embodiment with the form be recorded on the medium that can be read by computing machine.Equally, can be provided for making to be recorded in form on the medium that can be read by computing machine the computer program of each function of the processing unit of computer realization in the digital watermark detecting device of the embodiment according to top.

All examples described herein and conditional statement are intended to for instructing purpose to help reader understanding the present invention and the thought for the contribution of development this area by the inventor, and should be interpreted as being not limited to specifically described like this example and condition, the organizing also not relate to of the such example in instructions illustrates Pros and Cons of the present invention.Although described embodiments of the invention in detail, it should be understood that in the situation that without departing from the spirit and scope of the present invention, can carry out various changes for it, substitute and change.

Claims (13)

1. a digital watermark embedding apparatus comprises:

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

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

Described processing unit is configured such that the area that forms and be superimposed on the watermark recovery on each image comprised in described video data by a plurality of pixels with designated value changes in periodic mode in time according to the value of symbol comprised in described digital watermark information, and

Proofread and correct the value of each pixel comprised in the zone that each image in described video data and the described watermark recovery corresponding with described each image overlap each other by described designated value.

2. digital watermark embedding apparatus according to claim 1, wherein, described processing unit is configured to carry out to process to be superimposed upon watermark recovery on the first image in described video data in shape to be superimposed upon described video data in different immediately following the watermark recovery on the second image of described the first image.

3. digital watermark embedding apparatus according to claim 2, wherein, described processing unit is configured to determine the shape will be superimposed upon the described watermark recovery on described the second image, so that be superimposed upon respectively one of described watermark recovery on described the first image and described the second image, is not comprised in another of described watermark recovery.

4. digital watermark embedding apparatus according to claim 2, wherein, described watermark recovery comprises at least one watermark block formed by least one pixel with described designated value, and, quantity increase or minimizing along with described watermark block, the area of described watermark recovery increases or reduces, and wherein

Described processing unit is configured to determine the layout that will be superimposed upon the described watermark block comprised in the described watermark recovery on described the second image, so that described layout is uncorrelated with the layout that is superimposed upon the described watermark block comprised in the described watermark recovery on described the first image, make thus the described watermark recovery be superimposed upon on described the first image and the described watermark recovery be superimposed upon on described the second image differ from one another in shape.

5. digital watermark embedding apparatus according to claim 4, wherein, described watermark recovery comprises at least one first watermark block with first designated value and at least one second watermark block with second designated value different from described the first designated value, and wherein

Described processing unit is configured to carry out processing so that will be superimposed upon the quantity of described the second watermark block comprised in the described watermark recovery on described the second image different with the ratio of the quantity of the quantity that will be superimposed upon described the second watermark block comprised in the described watermark recovery on described the first image and described the first watermark block from the ratio of the quantity of described the first watermark block.

6. digital watermark embedding apparatus according to claim 1, wherein, the described watermark recovery when maximizing the area of described watermark recovery comprises a plurality of watermark block, and each watermark block is formed by the pixel with described designated value, and wherein

Described processing unit is configured to arrange described a plurality of watermark block, so that in described a plurality of watermark block, at least the first watermark block and the second watermark block are spaced.

7. digital watermark embedding apparatus according to claim 1, wherein, described processing unit is configured to carry out to process, so that the area of the described watermark recovery when described symbol has the first value described variation in time described variation when having second value different with described the first value when described symbol on phase place is different.

8. digital watermark embedding apparatus according to claim 1, wherein, described processing unit is configured to carry out to process, so that the area of the described watermark recovery when described symbol has the first value described variation in time described variation when having second value different with described the first value when described symbol on the cycle is different.

9. a data waterprint embedded method comprises:

Obtain video data and digital watermark information;

Make the area that forms and be superimposed on the watermark recovery on each image comprised in described video data by a plurality of pixels with designated value change in periodic mode in time according to the value of the symbol comprised in described digital watermark information; And

By proofread and correct the value of each pixel comprised in the zone that each image in described video data and described watermark recovery corresponding to described each image overlap each other by described designated value, to described video data, be embedded in described digital watermark information.

10. a computer readable recording medium storing program for performing, recorded digital watermarking embeddeding computer program on it, and described computer program makes computing machine carry out the processing that is embedded in digital watermark information to video data, and wherein, described program makes described computing machine carry out:

Make the area that forms and be superimposed on the watermark recovery on each image comprised in described video data by a plurality of pixels with designated value change in periodic mode in time according to the value of the symbol comprised in described digital watermark information; And

By proofread and correct the value of each pixel comprised in the zone that each image in described video data and described watermark recovery corresponding to described each image overlap each other by described designated value, to described video data, be embedded in described digital watermark information.

11. a digital watermark detecting device comprises:

Interface unit, obtain the wherein video data of embed digital watermark information; And,

Processing unit, detect and be embedded in the described digital watermark information in described video data, wherein

Described processing unit is configured to for each image calculation comprised in described video data for whole image or for the average pixel value of the reference zone that comprises watermark recovery, and the area of described watermark recovery changed in periodic mode in time with phase place or the cycle of the value of mating the symbol comprised in described digital watermark information;

Carry out frequency transformation by that comprise in the time period to corresponding with described symbol and one group of described average pixel value that be disposed in order with time series, calculate for describing the how time dependent frequency spectrum of described average pixel value; And

By extracting described periodically variable phase place or the cycle of the frequency component corresponding with the cyclical variation of the described area of described watermark recovery and the described area by calculating described watermark recovery according to described frequency component, obtain the value of described symbol from described frequency spectrum.

12. a digital watermark detection method comprises:

Obtain the wherein video data of embed digital watermark information;

For each image comprised in described video data, calculating is for whole image or for the average pixel value of the reference zone that comprises watermark recovery, and the area of described watermark recovery changed in periodic mode in time with phase place or the cycle of the value of mating the symbol comprised in described digital watermark information;

Carry out frequency transformation by that comprise in the time period to corresponding with described symbol and one group of described average pixel value that be disposed in order with time series, calculate for describing the how time dependent frequency spectrum of described average pixel value; And

By extract described periodically variable phase place or the cycle of the frequency component corresponding with the cyclical variation of the described area of described watermark recovery and the described area by calculating described watermark recovery according to described frequency component from described frequency spectrum, obtain the value of described symbol, and detect thus in described video data the described digital watermark information embedded.

A 13. computer readable recording medium storing program for performing, recorded the digital watermarking test computer programs on it, described computer program makes computing machine carry out and detects the processing that is embedded in the digital watermark information in video data, and wherein, described program makes described computing machine carry out:

For each image comprised in described video data, calculating is for whole image or for the average pixel value of the reference zone that comprises watermark recovery, and the area of described watermark recovery changed in periodic mode in time with phase place or the cycle of the value of mating the symbol comprised in described digital watermark information;

Carry out frequency transformation by that comprise in the time period to corresponding with described symbol and one group of described average pixel value that be disposed in order with time series, calculate for describing the how time dependent frequency spectrum of described average pixel value; And

By extract described periodically variable phase place or the cycle of the frequency component corresponding with the cyclical variation of the described area of described watermark recovery and the described area by calculating described watermark recovery according to described frequency component from described frequency spectrum, obtain the value of described symbol, and detect thus in described video data the described digital watermark information embedded.

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