Patent Application
20070003102
The present invention relates generally to a digital watermark-containing moving image transmission technique, and particularly to a technique of secretly embedding individual addition ID information that is set for each session for delivering moving image data to each individual user as a digital watermark into moving image data in a moving image display system that stores and displays digital moving image data, or a moving image delivery system that transmits stored digital moving image data using a network, and presents the data to a network-connected user.
In constructing a video-on-demand system for storing digital video contents in a server, and displaying the contents on the site or delivering the contents via a network according to a user request, preventing unauthorized use and leakage of the contents is one important issue that needs to be addressed. Various measures are used to realize content protection including setting access authority in the server to enable only authorized users to access the contents, conducting authentication using a specific ID assigned to a user terminal such as in a mobile telephone, and encrypting data so that only authorized users will be able to decode the data using a decryption key, for example.
As security techniques for ensuring copyright protection and preventing illegal content copying and distribution, the digital watermarking technique may be used in addition to authentication and encryption techniques. The digital watermarking technique embeds ID information into digital contents such as audio, music, still images, and video without affecting the quality of the digital content. Although this technique itself does not realize a function of blocking illegal copying like the encryption technique, hidden information such as that indicating the original owner of contents that have been copied may be extracted using this technique, and thereby, it may be possible to claim copyrights to the contents that have been illegally copied, for example (e.g., see “Digital Watermarking Techniques and their Comparative Indexes”, Matsui, Journal of the Institute of Image Electronics Engineers of Japan, Vol. 27, No. 5, pp. 483-491, 1998).
It is noted that there are mainly two methods for embedding a digital watermark in an image signal (e.g., see “Video Watermarking”, Sakazawa, Journal of the Institute of Image Electronics Engineers of Japan, Vol. 31, No. 3, pp. 421-425, 2002).
A first one of the methods involves dividing the pixels of image data into plural blocks, and directly embedding watermark information into bit information representing the brightness of the pixels (pixel brightness value). This method relies on the nature of human vision; that is, this method relies on the fact that a signal corresponding to a dark pixel located close to a bright pixel is difficult to recognize, and a slight change in brightness as a result of manipulation of a lower bit is not easily perceptible, for example. The method as is described above involving direct manipulation of the pixel brightness value has the advantage of requiring a small computation load. However, this method is disadvantageous in that the information added as a digital watermark may often be lost and fail to be reproduced as a result of image processes such as encoding, compression, or alteration of the image.
The other one of the methods involves transforming the image data into frequency components through fast Fourier transform (FFT), spectral diffusion, or discrete cosine transform (DCT), for example, and embedding watermark information into a particular frequency component while minimizing its influence on image quality. FIG.1 illustrates an example of using spectral diffusion to embed addition information as a digital watermark into one frame of an image signal. In this example, a pseudo random number data series having the same size as the image is provided, and this is divided into image plane regions. The pseudo random number data of the respective image regions are multiplied by 1 or −1 according to the bit sequence [0, 1] of the watermark information to be added to create a modulated pseudo random number data series. An image obtained by adding such data series to the original image signal is output as a watermark-containing image.
At the apparatus reproducing the image, a correlation coefficient between the watermark-containing image and the pre-modulated pseudo random number data is calculated for each region to reproduce the embedded watermark information bit sequence.
In this case, in order to maintain the quality of the image, the amplitude of the pseudo random number data is preferably set to be as low as possible. However, when the amplitude of the pseudo random number data is low, watermark information may be easily lost upon processing and compression of the watermark-containing image. Accordingly, trade-off between the above factors needs to be considered. Also, it is noted that the pseudo random number data and the division method for dividing an image into regions for the respective bits of the watermark information correspond to keys for reproducing the watermark information, and need to be kept under strict secrecy by the rightful owner of the contents.
Such a method involving transforming the image data into frequency components is advantageous in that the embedded watermark information is not easily lost through image processes such as image alteration or encoding/compression. However, this method has a disadvantage in that the processing time for embedding and extracting watermark information may be long since frequency transform and inverse transform processes need to be performed.
It is noted that by using the technique of embedding ID information as digital watermarks, the ownership of contents may be easily proved; however, this in itself does not have the effect of thwarting illegal copying. Thus, it is necessary to identify a copying source from illegally copied contents by embedding different sets of ID information into each set of contents being delivered through a network. If a system can be realized for determining the leakage (illegal usage) route of contents and identifying a willful infringer, such a system may make a great contribution to preventing illegal copying.
On the other hand, in the case of handling contents with a large capacity such as digital cinema and other contents adopting high image quality, the video contents to be delivered via a network are conventionally encoded and compressed due to restrictions in the transmission band and transmission cost for delivering the video contents. In this case, as is shown in
However, in a video contents display system for embedding digital watermarks into video contents according to the prior art, if watermark information is individually assigned to contents being delivered to each individual user, the process of adding digital watermarks has to be performed each time contents are delivered to a particular user. Also, in the case of conducting network transmission, since the encoded/compressed moving image data are stored in the server, the encoded data have to be decoded to conduct a process of embedding watermark information, and encoded once more. Such processes require a large computation work load, and are impractical both from a technical and economical standpoint.
This technical problem is exacerbated in the case of delivering video contents having a large capacity such as digital cinema. As a result, illegal copying of contents may not be effectively prevented by adding individual digital watermark information in the manner described above.
The present invention has been conceived in response to the problems described above, and its object is to provide a technique relating to digital watermark-containing moving image transmission that is implemented upon storing and displaying digital moving image data or transmitting the digital moving image data via a network, the technique being configured to prevent illegal copying through identifying the access route of delivered moving image data that are illegally used or illegally copied.
The above object of the present invention may be achieved by providing a digital watermark-containing moving image transmission system including:
a moving image reproducing apparatus that includes
an addition ID information detecting apparatus that divides the moving image data series displayed by the moving image reproducing apparatus into a plurality of regions, and detects the addition ID information for each of the divided regions using a digital watermark detecting circuit.
The above object may also be achieved by providing an information processing apparatus that is configured to transmit stored digital moving image data via a network, the apparatus including:
moving image input means for inputting one type of moving image data;
watermark-containing data generating means for embedding a plurality of differing sets of digital watermark information into the input moving image data, creating a plurality of watermark-containing moving image data series, and encoding the created watermark-containing moving image data series; and
ID information adding means for generating a new moving image data series from the plural watermark-containing moving image data series based on addition ID information including coded information corresponding to at least one of moving image identification information, time/date information, and user information.
It is noted that in one preferred embodiment of the present invention, the ID information adding means may be configured to successively select one image frame from a plurality of image frames of the plural moving image data series based on the addition ID information and output the successively selected image frames as the new moving image data series.
In another preferred embodiment of the present invention, the ID information adding means may be configured to successively select one group of image frames from a plurality of groups of image frames of the plural moving image data series based on the addition ID information and output the successively selected group of image frames as the new moving image data series.
According to another preferred embodiment, in the information processing apparatus of the present invention,
each of a plurality of image frames of the plural moving image data series may be spatially divided into a plurality of regions, and a plurality of divided region moving image data series may be generated for each of the divided regions; and
the ID information adding means may be configured to successively select one divided region image frame from a plurality of divided region image frames of the plural divided region moving image data series corresponding to one of the divided regions based on the addition ID information, compose the successively selected divided region image frames corresponding to said one of the divided regions with successively selected divided region image frames corresponding to another one of the divided regions, and output the composed divided region image frames as the new moving image data series.
The above object may also be achieved by providing a communication control apparatus in a system including a server and a terminal that are connected to a network, the apparatus including:
means for receiving a plurality of watermark-containing moving image data series from the server or another communication apparatus;
ID information adding means for generating a new moving image data series from the received plural watermark-containing moving image data series based on addition ID information including coded information corresponding to at least one of moving image identification information, time/date information, and user information; and
moving image delivering means for delivering the moving image data series generated by the ID information adding means to the terminal or another communication control apparatus.
As is described above, according to the present invention, plural digital watermark-containing moving image data series corresponding to one type of moving image data having plural differing sets of digital watermark information added thereto are created beforehand. Also, encoding/compression processes may be performed beforehand as is necessary or desired. Then, one of the plural digital watermark-containing moving image data series is successively selected with respect to the time direction; namely, with respect to every image frame, to compose a new moving image data series. Alternatively, each image frame of the plural moving image data series may be divided into regions to created plural divided region moving image data series, and a corresponding data portion may be retrieved from the divided region moving image data series for every divided region to compose a whole image. It is noted that the process of composing one moving image data series through partial selection of plural moving image data series may be performed at a node (communication control apparatus) on a network. Also, a redundant encoding process may be performed on the digital watermark information beforehand, and the frame/divided region selection process may be performed based on the processing results thereof.
It is noted that in the case of composing moving image data in frame units, identification information indicating the digital watermark information that is added to the respective frames of the moving image data may be embedded into the moving image data as addition information (addition ID information); and in the case of implementing image plane division, identification information indicating the digital watermark information added to the respective divided image regions may be embedded into the moving image data as addition information (addition ID information). In such cases, an image may have digital watermarks embedded therein in frame units or in divided region units and be encoded/compressed beforehand so that upon transmission, a moving image data series with the desired addition information added thereto may be easily generated by merely performing partial selection of data, and composition thereof. Accordingly, individual addition ID information may be assigned to large capacity contents such as movies through real-time processing.
Also, even in a case where plural users reside in the delivery network, by arranging the division/composition processes to be performed at an edge node (communication control apparatus) closest to the user terminal within the delivery network, individual addition ID information may be assigned to the respective users with a video stream limited to the types of digital watermarks by creating different combinations thereof.
Also, by performing redundant encoding on the addition ID information using error correction codes, even when digital watermark information is lost due to editing of contents, such an error may be corrected and the digital watermark information may be properly reproduced.
First, an outline of the present invention is described with reference to FIGS.3 and 4.
generating a new moving image data series from the plural watermark-containing moving image data series based on at least one of moving image identification information, time/date information, and/or user information (step 3); decoding and displaying the generated moving image data series (step 4); and dividing the displayed moving image data series into regions and detecting addition ID information for each of the divided regions using a digital watermark detecting circuit (step 5).
In the following, embodiments of the present invention are described with reference to the accompanying drawings.
The apparatus shown in this drawing includes a moving image database (DB) 10, an encoded data generating unit 20, an ID information adding unit 30, a reproducing unit 40, and an addition ID extracting unit 50.
The encoded data generating unit 20 includes an input unit 21, two watermark adding units 22A and 22B, two encoding units 23A and 23B, and two encoded data storage units 24A and 24B.
The input unit 21 is configured to read moving image data from the moving image DB 10, divide the read data into two, and output the divided data to the watermark adding units 22A and 22B, respectively.
The watermark adding units 22A and 22B are configured to embed respectively two sets of digital watermark information that are prepared beforehand into the two sets of moving image data.
It is noted that encoding units 23A and 23B may correspond to encoding circuits. The encoding units 23A and 23B are configured to encode and compress the digital watermark-embedded moving image data that are output from the watermark adding units 22A and 22B, respectively.
The encoded data storage units 24A and 24B are configured to store moving image data that are encoded and compressed by the encoding units 23A and 23B, respectively.
The ID information adding unit 30 includes a frame selecting unit 31 and an addition ID generating unit 32.
It is noted that the frame selecting unit 31 may correspond to a selector circuit. The frame selecting unit 31 is configured to select image data output from either the encoded data storage unit 24A or 24B of the encoded data generating unit 20 according to addition ID information supplied from the addition ID generating unit 32 and add the addition ID information to the selected image data to recompose one moving image data series.
The addition ID generating unit 32 is configured to encode information for identifying moving image data such as moving image identification information (contents information), data/time information, and/or user information as addition ID information, and supply the ID information to the frame selecting unit 31.
The reproducing unit 40 includes an image decoding unit 41. The image decoding unit 41 is configured to directly decode the moving image data series with addition ID information added thereto that is supplied from the addition ID information adding unit 30, and display the decoded image at a display unit 42 (e.g., monitor or a projector).
The addition ID extracting unit 50 includes a digital watermark detecting unit 51 and an addition ID determining unit 52.
The digital watermark detecting unit 51 is configured to detect a digital watermark from the displayed image data using a known digital watermark detecting circuit.
The addition ID determining unit 52 is configured to retrieve the addition ID information from a series made up of a combination of the detected watermark information. It is noted that the addition ID information retrieved in this case may correspond to moving image identification information, time/date information, and/or user information, for example.
In the following, the data series generated at the ID information adding unit 30 is described.
At the frame selecting unit 31, a stream containing watermark A (stream A) that is obtained by embedding digital watermark A into a video stream and encoding the video stream, and a stream containing watermark B (stream B) that is obtained by embedding digital watermark B into a video stream and encoding the video stream are input. The input digital watermark-containing streams A and B have a marker in each frame that includes a frame length, a frame number, and a frame head marker for enabling division of the respective streams into frame units, and the streams A and B each made up of a sequence of such frames include stream head markers at their respective heads. The frame selecting unit 31 selects frames of either stream A or stream B with the same frame number based on the addition ID information, and connects the selected frames to compose and output one stream (data series).
Step 101: at the addition ID generating unit 32, generate addition ID information beforehand.
Step 102: at the input unit 21, read moving image data from the moving image DB 10, divide the moving image data into two, and output the divided image data to the watermark adding units 22A and 22B, respectively.
Step 103: at the watermark adding units 22A and 22B, embed differing sets of digital watermark information into the moving image data, and output the digital watermark-embedded moving image data to the encoding units 23A and 23B, respectively.
Step 104: at the encoding units 23A and 23B, perform encoding and compression processes on the digital watermark-embedded moving image data.
Step 105: write the encoded/compressed moving image data in the encoded data storage units 24A and 24B, respectively.
Step 106: at the frame selecting unit 31, select/discard the encoded moving image data from the two encoded data storage units 24A and 24B based on the addition ID information, and recompose one moving image data series.
Step 107: at the image decoding unit 41, decode and display the recomposed moving image data (series) at the display unit 42.
Step 108: extract a digital watermark from the image data displayed by the display unit 42 using a known digital watermark detecting circuit, and retrieve the addition ID information from the extracted digital watermark.
According to the present embodiment, plural data encoding processes, ID adding processes, and moving image data decoding processes may be performed within one apparatus. That is, the present embodiment relates to a locally closed moving image system that does not use a network. This system is conceived in consideration of a case in which a third person illegally copies a moving image by capturing image data displayed on a projector or a monitor using a camera, for example, as opposed to obtaining a digital copy of the moving image data.
In the following, processes of the ID information adding unit (circuit) 30 are described in detail.
It is noted that in the following descriptions, it is assumed that the format of the addition ID information (e.g., information order and size), the type (number) of the digital watermark, and the bit sequence of the addition ID information (manner of combining moving image data with differing digital watermarks) are uniquely defined in the system beforehand.
In
The selector 311 selects and outputs either of the transmitted frame data according to the addition ID information that is transmitted one bit at a time from the addition ID information iterative transmission circuit 321 in accordance with the frame periods.
At an addition ID information extracting circuit directly receiving the moving image data series (video data), the image signal is decoded and reproduced by the image decoding circuit 41, after which watermark information is retrieved by the digital watermark detecting circuit (digital watermark detecting unit) 51 to obtain addition ID information from an arrangement of two types of digital watermarks. It is noted that the addition ID information extracting circuit of
The illustrated system includes an image server 100, a terminal 200, an addition ID extracting apparatus 300, and a network 400 that interconnects the image server 100 and the terminal 200.
It is noted that in the illustrated example, only one image server 100 and one terminal 200 are shown for the sake of simplifying the following descriptions; however, the system may be made up of plural image servers 100 and plural terminals 200 as well.
The image server 100 includes a moving image database (DB) 110, an encoded data generating unit 120, an ID information adding unit 130, and a communication unit 101. It is noted that the moving image database (DB) 110, the encoded data generating unit 120, and the ID information adding unit 130 have functions identical to those of the moving image database (DB) 10, the encoded data generating unit 20, and the ID information adding unit 30 of the first embodiment, and thereby, detailed descriptions of these components are omitted.
The terminal 200 includes a network transmitting unit 244, an image decoding unit 241, a network receiving unit 243, and a display unit 242. It is noted that the image decoding unit 241 and the display unit 242 have functions identical to those of the image decoding unit 41 and display unit 42 of the first embodiment, and thereby, detailed descriptions of these components are omitted.
The network transmitting unit 244 is configured to issue a moving image data request to the image server 100.
The network receiving unit 243 receives from the image server 100 encoded digital watermark-containing moving image data having ID information added thereto via the network 400.
It is noted that the addition ID detecting unit 350 of the addition ID extracting apparatus 300 has functions that are identical to those of the addition ID extracting unit 50 of the first embodiment, and thereby, detailed descriptions thereof are omitted.
Step 201: issue a moving image data request at the network transmitting unit 244 for transmission from the terminal 200 to the image server 100.
Step 202: at the image server 100, when the communication unit 101 receives the request from the terminal 200, read the moving image data from the moving image DB 110, and embed digital watermarks into the moving image data at the encoded data generating unit 120.
Step 203: further, at the encoded data generating unit 120, perform encoding/compression processes on the digital watermark-embedded moving image data, and store the encoded moving image data.
Step 204: at the ID information adding unit 130, select/discard the stored moving image data based on the addition ID information, add the addition ID information, recompose the moving image data, and generate one moving image data series. It is noted that these processes are identical to the operation processes of FIGS.6 and 8 described in relation to the first embodiment.
Step 205: transmit the recomposed moving image data (series) from the communication unit 101 to the terminal 200 requesting for the moving image data via the network 400.
Step 206: at the terminal 200, receive the moving image data (series) delivered from the image server 100 at the network receiving unit 243, and decode the received moving image data at the image decoding unit 241.
Step 207: display the decoded moving image data at the display unit 242.
Step 208: input the image data displayed at the display unit 242 to the addition ID extracting apparatus 300.
Step 209: detect a digital watermark from the image data at the addition ID detecting unit 350 of the addition ID extracting apparatus 300.
Step 210: retrieve the addition ID information from the detected watermarks based on the series of combined watermark information.
The illustrated system includes an image server 100, a terminal 200, a delivery network node 500, an addition ID extracting apparatus 300, and a network 400 interconnecting the image server 100, the terminal 200, and the delivery network node 500. It is noted that
The system according to the present embodiment is characterized in that the functions of the ID information adding unit 130 of the imager server 100 in the second embodiment are realized in a delivery network node 500.
The delivery network node 500 includes an ID information adding unit 530 and a communication unit 510.
The interface 501 with an interconnecting node (e.g., another delivery network node) includes plural data receiving units. Encoded moving image streams including watermark information A and B, respectively, and addition ID information may be received through one of the data receiving units of the interface 501 with an interconnecting node. The router switch 503 for separating and transmitting data is configured to separate data for each destination terminal and delivery network to which a moving image is to be delivered. The received data are separated into two moving image streams along with addition ID information. Then, selection and composition processes are performed on the two streams by the selector 311 according to the addition ID information in a manner similar to that described in
Step 301: issue and transmit a request for moving image data from the terminal 200 to the image server 100 via the delivery network node 500.
Step 302: in the image server 100, when the communication unit 101 receives the request from the terminal 200, read the moving image data from the moving image DB 110, and embed digital watermarks into the moving image data at the encoded data generating unit 120.
Step 303: further, at the encoded data generating unit 120, perform encoding/compression processes on the digital watermark-embedded moving image data and store the encoded moving image data.
Step 304: transmit the stored moving image data from the communication unit 101 to the delivery network node 500.
Step 305: at the communication unit 510 of the delivery network node 500, receive plural sets of encoded/compressed moving image data with differing digital watermarks embedded therein that are transmitted from the image server 100; and at the ID information adding unit 530, select/discard the received moving image data based on addition ID information, add ID information to the selected moving image data, and recompose the selected moving image data to generate one moving image data series.
Step 306: transmit the recomposed moving image data (series) via the network 400 to the terminal requesting for the moving image data.
Step 307: in the terminal 200, receive the moving image data (series) delivered from the image server 100 at the network receiving unit 243, and decode the received moving image data at the image decoding unit 241.
Step 308: display the decoded moving image data at the display unit 242.
Step 309: input the image data displayed by the display unit 242 to the addition ID information extracting apparatus 300.
Step 310: in the addition ID information extracting apparatus 300, detect the digital watermark from the input image data at the addition ID detecting unit 350.
Step 311: retrieve addition ID information from the series of detected watermarks.
In the following, specific examples of the present invention are described with reference to the accompanying drawings.
The present example illustrates a specific example of embedding addition ID information into encoded digital watermark-embedded moving image data.
This drawing illustrates an example of decomposing/composing a video stream in frame units (time series) according to addition ID information, wherein each bit of the addition ID information indicates the type of digital watermark to be retrieved.
This drawing illustrates a case in which the selector 311 selects frames from two series of moving image data (video streams) corresponding to identical video contents having two types of digital watermarks “A” and “B” added thereto, the selection being based on addition ID information “01010” which results in the composition of addition ID information-containing moving image data made up of five consecutive frames; namely, a first frame with digital watermark “A”, a second frame with digital watermark “B”, a third frame with digital watermark “A”, a fourth frame with digital watermark “B”, and a fifth frame with digital watermark “A”.
At the reception side, “ABABA” is detected from the consecutive frames to determine the addition ID information “01010”. It is noted that although two types of digital watermarks are used in the illustrated example, as a general rule, when 2n types of digital watermarks are used, n bits of addition ID information may be used to indicate the type of digital watermark.
Generally, the manner in which digital watermarks are added and the manner in which the digital watermarks are detected are kept as confidential information by the rightful owner of the contents. In the case of using the conventional spectral diffusion scheme of
The addition ID information may include static information pertaining to the video contents such as title information and copyright information, the registered number of the apparatus including the ID information adding unit 30, and the delivery destination user name, the delivery time/date, and the delivery route over the network for each contents delivery session, for example. By adding unique information to the contents being delivered, an illegal user may be accurately identified. It is noted that in the case of encoding the addition ID information, encryption of the addition ID information may be performed (in such a case, decoding of the encryption is performed in the addition ID decoding process performed at the addition ID extracting side).
In the following, another example of adding addition ID information is described where video contents are composed by selecting one group of consecutive frames per unit from plural groups of image data series having differing sets of digital watermark information according to addition ID information which video contents are then delivered.
It is noted that in an encoding scheme represented by the MPEG scheme that relies on inter-frame difference in information compression, the encoded video stream may not be decomposed into individual frame data units. However, even in such an encoding scheme, the encoding process is still performed in units of the so-called GOP (Group of Pictures) made up of several to several dozen frames. Accordingly, instead of changing the watermark information in frame units, contents including watermark information may be selected in GOP units according to the addition ID information to compose one stream.
The example described below illustrates a case of spatially dividing individual image frames, selecting from plural image data series having differing digital watermark information one divided image plane region per unit according to addition ID information, composing plural of the selected divided image plane regions, and reproducing the composed video contents.
In the case of using image plane division in adding addition ID information, a number of connections equal to the number of image plane divisions are established between the moving image server and the delivery network node for each type of watermark information. Specifically, when the division number is equal to n, and two types of watermark information, A and B, are used, 2n connections are established. Then, for each connection, a frame partition symbol-containing video stream of one divided image plane is transmitted from the moving image server to the delivery network node, and either a video frame containing digital watermark A or a video frame containing digital watermark B is selected per divided image plane unit according to the addition ID information (i.e., 0 or 1). Then, the selected divided image planes are composed into data for transmission to a user video terminal.
It is noted that the selection per divided image plane unit and the selection per frame unit may be used together. For example, time/date information may be embedded in the selection process performed per divided image unit, and other information may be embedded in the selection process performed per frame unit. A code representing each frame may be set using one divided image plane as a parity bit, wherein if the number of divided image planes representing “1” out of all the divided image planes corresponds to an even number, the code is set to “0”, and if this number corresponds to an odd number, the code is set to “1”, for example.
In the example of
According to the method using image plane division as is described above, the amount of information that may be added to one frame may be increased by increasing the number of image plane divisions. However, with such an increase, the number of pixels per divided image plane is decreased resulting in the degradation of the detection accuracy of the digital watermark information. In a case where an upper limit is imposed on the number of divisions, a method of developing addition ID information between frames in the temporal direction may be used along with the above method.
It is noted that the above-described means for assigning differing types of digital watermarks to one type of video contents to create plural video streams, and decomposing and composing the video streams according to addition ID information may be implemented at the image server 100 according to the previously-described second embodiment. Also, the above means may be implemented at an edge delivery network node 500 that is closest to the user terminal 200 in the network delivery system according to the previously-described third embodiment.
The present example illustrates a case of applying the system according to the third embodiment to a video delivery technique using plural video streams corresponding to identical video contents with differing watermark information.
According to the present example, instead of composing a video stream for each user at the video server 100 and individually delivering the video stream over the network 400, two or more series of video streams containing differing digital watermark information may be decomposed/composed according to addition ID information for each user at the delivery network node 500 as is shown in
In the following, the delivery network node 500 used in the fourth example is described in greater detail. The delivery network node 500 used in the fourth example includes the configuration shown in
The addition ID information may include moving image identification information, time/date information, and user information, for example, details of which are described below.
The moving image identification information may be transmitted to the delivery network node 500 from the image server (video server) and/or an image data management server (not shown), and may include content ID and/or copyright ID information unique to the moving image contents, and ID information unique to the image server such as IP address information and/or MAC address information, for example.
The time/date information may be transmitted from an online time server using a time information protocol (e.g., NTP, Network Time Protocol, RFC-1305), for example. The time/date information to be added corresponds to the timing at which the time/date information is added as addition ID information and is obtained from the time server by the delivery network node 500. In this way, the time and date at which the video stream passes the delivery network node 500 may be recorded.
The user information may be transmitted from the user video terminal 200, and/or user management server (not shown), for example, and may include ID information unique to the user video terminal 200 such as IP address information and/or MAC address information, for example.
Also, the delivery network node 500 may use its own identification information as the addition ID information. The identification information of the delivery network node 500 may include ID information unique to the delivery network node such as IP address information and/or MAC address information, for example.
It is noted that in the case of using corresponding IP address information as ID information unique to the image server and ID information unique to the user video terminal, a source address and a destination address may be acquired from a header portion of an IP packet, and the acquired address information may be used as addition ID information. Also, in the case of using MAC address information, a source MAC address and a destination MAC address may be acquired from a header portion of the Ethernet, and the acquired address information may be used as addition ID information.
Also, it is noted that content ID and copyright ID that are unique to the moving image contents may be embedded as moving image identification information into one or both of digital watermarks A and B. In this case, the delivery network node 500 does not have to newly add the content ID and/or copyright ID to moving image contents.
As is described above, an edge delivery network node 500 that is closest to a user video terminal 200 temporarily stores encoded video data series (video streams) as illustrated in
Also, it is noted that a predetermined pattern (e.g., eight consecutive “0”s) is inserted to the front and back ends of addition ID information as partition symbols (delimiters), and the addition information is iteratively transmitted at predetermined intervals. By arranging an addition ID detecting apparatus to detect such delimiters, the iterative addition ID information may be reproduced.
In a case where video streams are delivered from an image server to a user video terminal via plural delivery network nodes 500 as is illustrated by the network configuration shown in
For example, at an edge delivery network node that is closest to an image server, ID information unique to the moving image server, ID information of the edge node, and time/date information pertaining to the timing at which the video streams pass through this node may be added. Then, at an intermediate delivery network node, ID information of this intermediate delivery network node and time/date information pertaining to the timing at which the video streams pass through this delivery network node may be added. Further, at an edge delivery network node that is closest to the user video terminal, ID information of this edge delivery network node, time/date information pertaining to the timing at which the vide streams pass through this delivery network node, and ID information unique to the user video terminal may be added.
According to such an arrangement, the respective delivery network nodes receive a video stream of digital watermark A and a video stream of digital watermark B in addition to the addition ID information and the video stream with delimiters added thereto.
The edge delivery network node that is closest to the user video terminal successively delivers the video stream of digital watermark B corresponding to “1”, for example, to the user video terminal during the interval after the video stream with the respective items of addition ID information and the delimiters added thereto is delivered and before transmission of a next succession of addition ID information is started.
The delivery network nodes other than the edge delivery network node that is closest to the user video terminal operate in the manner described below. During the time the video stream with the respective addition ID information and the delimiters added thereto is being transmitted, only the video stream is delivered to the next delivery network node. During the time before transmission of the next succession of addition ID information is started, the video stream of the digital watermark A and the video stream of the digital watermark B are both directly transmitted. By transmitting the video streams of watermarks A and B in this manner, at the next delivery network node, further addition ID information may be added using the time during which both the video stream of the watermark A and the video stream of the watermark B are remaining at the node.
Therefore, the transmission interval for successively transmitting plural sets of addition ID information partitioned by the delimiters is determined in consideration of the length of the final addition ID information to be added. Also, in the case of successively adding differing addition ID information through intermediate network nodes, the required network transmission capacity may change depending on the number of users.
The present example relates to a case of composing three types of streams in the delivery network node 500 from two video streams.
The servers 100A and 100B transmit via network transmitting circuits 101A and 101B two series of moving image data to each of three delivery network nodes 500 having ID information adding circuits 530 that are connected to the network 400. Each delivery network node 500 is arranged to receive moving image data, generate addition ID information according to the site (terminal) at which the moving image data are to be displayed, and recompose a moving image data series by conducting a selecting/discarding process on the two series according to the generated addition ID information.
The composed moving image data series is received at the network receiving circuit 243 of the terminal 200 and decoded at the image decoding circuit 241 to be displayed/reproduced. In this case, even when the number of nodes and/or the number of sites (terminals) receiving the image data series is increased, the moving image data series may be identified by the different ID information, and thereby, only two types of large capacity moving image data series need to be transmitted over the network 400.
In one scenario, a malicious user may tamper with delivered contents by receiving at least two video streams and editing the received video streams to reconstruct one video stream. The present example illustrates measures for countering such an attack.
In order to counter an attack made by a malicious user, an error correction encoding circuit 325 may be used to provide redundancy to the addition ID information beforehand as is shown in
In the example illustrated in
Also, by implementing redundant encoding, addition ID information may be reproduced from frame-rate-converted video. For example, as is illustrated in
Also, according to an embodiment of the present invention, the apparatus configuration shown in
Also, the apparatus configurations of the image server, the terminal, and the addition ID extracting apparatus may be realized by programs as well. In such a case, the programs may be installed in computers that are used as the image server, the terminal, and the addition ID extracting apparatus, and may be executed by control means such as a CPU. Also, such programs may be distributed via a network.
Similarly, the apparatus configurations of the image server, the terminal, the delivery network node, and the addition ID information extracting apparatus of
Also, it is noted that the programs may be stored in hard disk apparatuses or movable storage media such as a flexible disk or a CD-ROM that are connected to the computers used as the image server, the terminal, the delivery network node, and the addition ID information extracting apparatus. In such cases, the programs may be read from the storage media and executed by control means such as a CPU upon implementing the present invention.
As is described above, according to the present invention, a moving image data series with at least one of individual ID or security information for each individual user added thereto may be delivered according to a request issued by the relevant user. In this way, when contents copied with malicious intent are distributed to a third person, a determination may be made as to when and by whom the contents have been delivered so that a significant contribution may be made to preventing illegal copying of contents.
Particularly, as is illustrated in the configuration of delivery network nodes shown in
Also, since text information may be added as digital watermark information beforehand, high-work load real-time processing may be unnecessary upon delivery.
Further, methods that require high computational work load and are not suitable for real-time processing may be used in the present invention, and thereby, a method of assigning a digital watermark with high resistance to processing and compression may be used. It is noted that there may be cases in which complete addition ID information cannot be retrieved from individual frames; however, provided that a subject video has a sufficient running time for serving its purpose of displaying video contents, addition ID information may be properly detected from such video.
Further, the present invention is not limited to the embodiments described above, and variations and modifications may be made without departing from the scope of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2003-112853 | Apr 2003 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP04/05357 | 4/15/2004 | WO | 10/17/2005 |
