KR20090110730A - Apparatus and method for embedding and extracting buyer information in visible video watermarking - Google Patents

Abstract

PURPOSE: A device for inserting and extracting purchaser information to a visible video watermarking technology is provided to perform contents copyright protection and digital extraction function. CONSTITUTION: A device for inserting and extracting purchaser information to a visible video watermarking technology includes as follows. A video content is decoded. Information about the location of owner information logo or color is changed in a decoding module(120). The changed owner information logo is inserted in the video content. The owner information logo shows the information about the copyright holder of the video content or the provider.

Description

APPARATUS AND METHOD FOR EMBEDDING AND EXTRACTING BUYER INFORMATION IN VISIBLE VIDEO WATERMARKING}

The present invention relates to an apparatus and method for concealing buyer information in a visible video watermarking technique, and more particularly, to alter content for a logo representing a copyright owner or content provider included in video content to conceal content buyer information. An apparatus and method that can be used.

Recently, when a content provider distributes video content to a user's terminal through a wired or wireless network, the distributed video content is recompressed and stored by a DVR or a capture device, which is illegally distributed by an illegal distributor, thereby infringing content copyright. It is happening. Accordingly, watermarking, in which information of a copyright holder is inserted in a content for copyright protection, has been in the spotlight.

Watermarking may be classified into visible watermarking and invisible watermarking depending on visibility of the watermark. Visible watermarking is a method of inserting copyright holder's information visible in the original image. Invisible watermarking is a technique of inserting a watermark so that it cannot be visually detected using the sensory limits of the human visual system (HVS). Invisible watermarking may be further classified into spatial domain watermarking and frequency domain watermarking according to a method of inserting a watermark.

For copyright protection of video content, a logo representing the information of the copyright holder or the content provider (distributor) of the content is generally added to the content using a visual watermarking technique. However, the added logo represents information of the copyright holder or the content provider, but does not include information on the user who uses the content. Therefore, if there is a dispute related to the copyright of the video content, it is possible to track who the original copyright owner was, but it is difficult to track who distributed it. Accordingly, a method is used for concealing the information of the video content buyer in the content. This way of inserting the information of the buyer is also referred to as "digital fingerprinting (Digital Fingerprinting)".

Digital fingerprinting is the same as digital digital watermarking in terms of inserting confidential information into digital content, but digital digital watermarking can be used to track illegal content distributors by inserting the information of content buyers rather than information of copyright holders or content providers. Different from marking This is done by inserting a unique number (eg, an ID of a user terminal) in the content that can identify the buyer.

However, invisible watermarking algorithms are mainly used to insert buyer information. However, invisible watermarking algorithms are applied to high-definition and high-definition HD contents, and thus they tend to be avoided because they may cause deterioration of original image quality. Therefore, there is a need for a method of protecting the interests and rights of copyright holders by concealing buyer information in content by visual watermarking.

In order to solve the conventional problems as described above, the present invention inserts a logo indicating owner information by using visible watermarking technology in high-definition and high-definition HD content, and changes the position and / or quantized color value of the logo. It is an object of the present invention to provide an apparatus and method for inserting and extracting buyer information. In other words, by invisibly inserting the buyer information into an image logo or a text logo indicating the owner information of the content, illegal distributors can be tracked and detected, and a device and method that is robust against transcoding attacks, rotation and scale attacks are provided. For the purpose of

An apparatus for inserting an owner information logo into video content according to the present invention and simultaneously inserting buyer information,

Means for decoding video content; And

Alteration and insertion means for changing information about the position or color value of the owner information logo to conceal the buyer information in the decoded video content, and inserting the changed owner information logo into the video content,

The owner information logo may be a logo representing information about a copyright holder or a provider of video content.

In addition, an apparatus for extracting the inserted buyer information while inserting the owner information logo in the video content according to the present invention,

Means for performing edge detection logic on the video content; And

Means for obtaining a position at which a pattern of a reference logo having a contour information of the owner information logo matches the pattern of the video content, for detecting a change in the information on the position or color value of the owner information logo,

The owner information logo may be a logo representing information about a copyright holder or a provider of video content.

In addition, as a method of inserting the owner information logo in the video content according to the present invention and at the same time buyer information,

Decoding video content; And

Changing and inserting information about the location or color value of the owner information logo to conceal the buyer information in the decoded video content, inserting the changed owner information logo into the video content,

The owner information logo may be a logo representing information about a copyright holder or a provider of video content.

In addition, as a method of extracting the inserted buyer information while inserting the owner information logo in the video content according to the present invention,

Performing edge detection logic on the video content; And

Obtaining a position at which the pattern of the reference logo having the contour information of the owner information logo and the pattern of the video content are matched to detect a change in the information on the position or color value of the owner information logo,

The owner information logo may be a logo representing information about a copyright holder or a provider of video content.

According to the apparatus and method according to the present invention, the purchaser information can be invisibly inserted into the image logo or the text logo indicating the owner information of the high-definition and high-definition HD content, and the inserted information can be extracted. That is, when video content is redistributed without permission by an illegal distributor, if the buyer information is inserted in accordance with the present invention, it is possible to track and detect the illegal distributor (regarded as distributed by the buyer) by extracting the buyer information. Accordingly, the present invention can simultaneously perform content copyright protection and digital forensic marking.

The apparatus and method according to the invention are also robust against transcoding attacks, rotational and scale attacks.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 is a block showing a schematic configuration of an apparatus for inserting information of a content purchaser into a logo (hereinafter referred to as 'owner information logo') representing information about a copyright holder or a content provider included in video content according to the present invention; It is also. The inserting device 100 may non-cognitively determine the position and / or color value of the owner information logo to indicate the buyer information before inserting the owner information logo into the video content and the decoding module 120 for decoding the received video content. Changing owner information logo changing and inserting module 140.

Video content includes various visible content, such as picture files. In addition, many content owners insert logos representing their information into the content through visual watermarking techniques, which can be made of images or text. The inserting device 100 mainly operates in a purchaser terminal that receives the video content from the copyright holder of the video content or the provider providing the same. When the video content owner distributes the content to the purchaser terminal through the wired or wireless network, the owner information logo is transmitted once. However, when transmitted alone to a specific terminal such as a set-top box (STB), the insertion device 100 included in the specific terminal may have an owner information logo in advance.

Decoding module 120 first decodes the received video content and passes the decoded video content to owner information logo change and insertion module 140. The owner information logo change and insertion module 140 uses the visual watermarking technique to unknowingly insert the information of the buyer using the content into the owner logo to output the video content with the buyer information embedded therein.

The owner information logo change and insertion module 140 may be classified into a method of changing location information of the owner information logo and a method of changing color information, and each method will be described in detail below.

1. Insert buyer information by changing the location of the owner information logo

By changing the position of the owner information logo included in the video content, it is possible to conceal the information of the buyer who uses the video content to the logo, which will be described with reference to FIGS. 2 and 3.

2 illustrates an example of a method of expressing buyer information by changing a position of an owner information logo.

In this embodiment, the owner information logo is inserted into the upper left corner of the video frame of the video content and distributed by visual watermarking technique. The position of the owner information logo can be moved in the X, Y axis, for example, in the 360 degree direction with respect to the upper left corner. Here, the index that can be moved on the X and Y axes is a index that can express the buyer information. This may be configured as a bit index table (mapping table) as described below. In FIG. 2, owner information is moved in nine directions with the same radius R, and the number of moving branches is nine (I1 to I9). Therefore, in the case of FIG. 2, the index value is 0 to 8, and 3 bits of buyer information can be expressed in one frame.

Although FIG. 2 illustrates only nine branches, the present invention is not limited thereto, and the position change may be divided by the radius R in the direction of 1 degree, and the total branches when the size of R is divided into several stages again. The number can grow infinitely. Accordingly, the number of bits that can represent the buyer information can also increase infinitely.

3 illustrates a method of expressing buyer information by changing a positional relationship therebetween when there are a plurality of image patterns or a text logo in an owner information logo.

When the owner information logo is composed of several image patterns, the positional relationship between the image patterns is changed and converted into an information expression structure. In addition, when the owner information logo is made of text, the positional relationship between the characters of the text is changed and converted into an information expression structure.

3 shows a change in the positional relationship when the owner information logo is made of text "MA". "MA" consists of two letters 'M' and 'A', and the distance change between the two letters can be represented by four cases, for example. That is, if 'A' has moved inwards (II1), 'A' has moved outwards (II2), 'A' has moved downwards (II3), and 'A' has moved upwards Four cases of case (II4) are possible. When this is used as an information expression structure, two bits of information can be represented. In addition, the above example represents only two bits of information, but the present invention is not limited thereto, and the number of bits for representing buyer information may be infinitely increased according to the number of characters or image patterns in the text constituting the owner information logo. . The correspondence between the bit information representing the positional information and the buyer information may be configured as a bit index table.

2. Insert buyer information by changing the color of the owner information logo

The owner information logo is designed by color value when using a gray level image or a color image. The color value used here is used as a structure to represent buyer information.

First, there is a method of using color values quantized at the same equal interval level in the owner information logo. When the gray level image is used, the color value ranges from 0 to 255. Divide this color value into regular intervals according to the interval Q. Accordingly, a total of Q color values are obtained, which can be used as the number of Q buyer information representation bits. For example, if the quantization step is set to four steps, a total of 65 quantized color values are produced. The correspondence relationship between the color information and the bit information representing the buyer information may be configured as a bit index table. In this case, the index value may be 0 to 64, and total 6 bits of buyer information may be represented. In this case, since 65 is a value exceeding 6 bits, it can be represented by 7 bits and is excluded because it does not represent all 7 bits. Therefore, a total of 6 bits of buyer information are represented in one frame.

There is also a method of using different color patterns. This method is used when the logo included in the video content has a plurality of different patterns. For an image or text of a logo, a plurality of patterns having different color values but having the same size and style may be generated. At this time, the number of branches of the generated pattern is the number of bits that can represent buyer information. For example, if there are 16 different patterns, a total of 4 bits (2 ⁴ = 16) of buyer information can be represented in the logo in one frame. Further, according to the number of different patterns, buyer information that can be inserted into the owner information logo can also increase indefinitely. Correspondence relationship between different color patterns and bit information representing buyer information can also be configured as a bit index table.

3. 1 and above 2 of  Insert buyer information combining methods

The buyer information can be inserted by combining the method of changing the positional information of the owner information logo with the method of changing the color information. That is, it is possible to combine two or more of the four methods described above in 1 and 2. For example, when the owner information logo is composed of text, the change in positional relationship between text characters is classified into nine cases, the change in position of the entire logo is classified into four cases, and the quantized color of the logo is also included. If the value stage is set to 10 stages, the insertable buyer information may be 9 * 4 * 10 = 360 pieces in total. That is, it is possible to represent 8 bits of information in one frame.

In another example, when the owner information logo is text, if the number of change in positional relationship between text characters is four and the number of change in total logo position is nine, the number of bits of buyer information that can be expressed is 5 bits in total. Becomes Table 1 below shows a bit index table relating to the correspondence between the change in location information and buyer information in this example.

Positional relationship between text characters The overall position of the logo Buyer information II1 I1 00000 II1 I2 00001 II1 I3 00001 ... ... ... II2 I1 01010 II2 I2 01011 ... ... ... II4 I9 11111

<Bit index table structure expressing buyer information by combining change of positional relation between text characters and positional relation of whole logo>

Next, referring to Fig. 4, an apparatus for extracting information of a buyer inserted into video content according to the present invention will be described.

4 shows an apparatus for extracting buyer information inserted by the insertion apparatus 100 according to the present invention as shown in FIG. The detection apparatus 200 detects an edge of a video frame, an edge detection module 220, a pattern matching module 240 for obtaining a matching position between the video content and a reference logo, and a color value detection for calculating a color value within the matching position. Module 260.

The detection device 200 receives a video frame of the video content so as to identify the purchaser of the distributed video content. The input video frame is input to the edge detection module 220, and the video frame from which the edge is detected is extracted.

The video frame at which the edge is detected is input to the pattern matching module 240. The pattern matching module 240 further receives a reference logo having contour information for the pattern of the owner information logo included in the video frame for the matching operation.

The pattern matching module 240 determines a matching position using a video frame and a reference logo through a matching process. Pattern matching can be made using a variety of known algorithms, such as cross correlation, mean absolute difference (MAD) or mean square error (MSE) algorithms.

The pattern matching module 240 calculates coordinate values WM _ext of X and Y having the largest value as the result of pattern matching, as shown in Equation 1 below.

Here, Frm _i represents a video frame index after edge detection, and Ref is a reference logo obtained by obtaining contour information of the owner information logo. In order to increase the accuracy of the search speed and to improve the performance of the matching result, the visible logo area may be artificially selected and used. The selected area in the frame is then Frm _i . The MH () function is a pattern matching function. When Equation 1 is smaller than the predetermined threshold Th, it is determined that the rotation or scale attack has been performed, and thus, an exhaustive search is performed through rotation and scaling step by step. The operation of Equation 1 repeatedly detects bit information in a frame until a specific bit of the last bit information string is found, accumulates the extracted bit information, and configures the total buyer information.

If there are multiple image patterns or text in the owner information logo, the location information and / or pattern index is retrieved for each image pattern and each text character. In the case of using a change in the position of the owner information logo or using a different color pattern, the buyer information may be known through coordinate values or index values from the pattern matching module 240.

When buyer information is inserted using quantized color values at the same equal interval level, the following process is further involved. When the coordinate value is calculated in the pattern matching module 240, the color value calculation module 260 receives the calculated value and obtains the color value of the owner information logo portion located in the coordinate position. The color value table value R (x, y) is calculated by Equation 2 below.

Where xloc and yloc represent positions calculated from Equation 1.

Using the x, y position, logo mask and video frame obtained in Equation 2 above, the average color value of the buyer's logo based on the x, y position is calculated using Equation 3 below. Here, only the color value in the logo area is obtained using the logo mask pattern TLMask composed of 0 (background) and 1 (foreground).

Here, the purchaser information may be extracted by obtaining a quantized color level using the average color value calculated by Equation 3 and converting the quantized color level into bit information. Here, M is the number of pixels in the horizontal direction of the logo, N is the number of pixels in the vertical direction of the logo. In addition, the owner information logo is overwritten when the watermark is inserted.

FIG. 5 illustrates a flowchart illustrating a process of inserting buyer information into video content received at a buyer terminal in one embodiment according to the present invention.

First, when the owner information logo and the video content is received by the buyer terminal (S500), the buyer terminal decodes the received video content (S502). For the decoded video content, in order to insert information that can represent the buyer, such as the ID of the buyer terminal, for example, the position or color value of the owner information logo is changed according to the buyer information and inserted into the video content. (S504). Since the change of the logo has been described above, a detailed description thereof will be omitted. The logo may be changed by applying one or more changes to the location information of the logo, the positional relationship between image patterns or characters in the logo, color values, color values for a plurality of logos having color values of different patterns, and the like. That is, although one of the four above may be changed, the number of bits that can be represented by combining any two to four may be increased. When the owner information logo is changed and inserted, the video information into which the buyer information is inserted is acquired (S506). Such video content can then be redistributed by the buyer, where the buyer can be tracked according to a process as shown in FIG.

6 shows a flowchart illustrating a process of detecting buyer information embedded in video content in one embodiment according to the present invention.

The edge detection logic is applied to the video content in which the buyer information is inserted (S600). The pattern matching algorithm is applied again to the content of which the edge is detected (S602). If the location information is changed or the buyer information is inserted using different color patterns, the buyer information can be confirmed only by the matching information known in this step S602. However, if the buyer information is inserted by changing the quantized color value at the same equal interval, the buyer information can be known by obtaining the color value using the matching position and the logo mask known in step S602 (S604). Buyer information may be found with reference to the bit index table.

7 is a diagram illustrating an example of a service structure using the system of the present invention.

The video content provider transmits the video content to the purchaser's terminal (eg IPTV, PC, etc.). The logo representing the copyright holder information is initially sent only once. However, if content is transmitted to a specific terminal such as a set-top box alone, it may be stored in the terminal in advance. The terminal inserts the terminal buyer's information into the video content through visual watermarking that changes the owner information logo. Terminal buyers may compress, store or redistribute such video content. Some buyers may distribute video content without permission of the copyright holder, and the copyright holder uses a watermark detector to track the unauthorized distributor. When the distributed video content is input to the detector, the buyer information can be known from the change of the logo included in the content. Thus, the copyright holder can obtain advantageous evidence of this buyer information.

The various illustrative logical blocks and algorithm steps described in connection with the embodiments disclosed herein may be implemented in electronic hardware, computer software, or a combination thereof.

In addition, although the invention has been particularly shown and described with reference to the above embodiments, it has been used only for the purpose of illustration and those skilled in the art to which the invention pertains may have the same definitions as defined in the appended claims. It should be understood that various modifications may be made without departing from the spirit and scope of the invention.

1 is a block diagram illustrating an apparatus for inserting buyer information into video content simultaneously with insertion of an owner information logo according to an embodiment of the present invention.

Figure 2 illustrates one embodiment of inserting buyer information by changing the position of the owner information logo in accordance with one embodiment of the present invention.

3 illustrates one embodiment of inserting shopper information by changing the positional relationship between characters of a text logo in accordance with one embodiment of the present invention.

4 is a block diagram illustrating an apparatus for detecting buyer information inserted at the same time as the owner information logo is inserted into video content according to an embodiment of the present invention.

5 is a flowchart illustrating a process of inserting buyer information into video content according to an embodiment of the present invention.

6 is a flowchart illustrating a process of extracting buyer information embedded in video content according to an embodiment of the present invention.

7 is a diagram illustrating an example of a service structure using a system according to an embodiment of the present invention.

※ Explanation of code for main part of drawing

100: buyer information inserting device 200: buyer information extracting device

120: decoding module 220: edge detection module

140: owner information logo change and insertion module 240: pattern matching module

260: color value calculation module

Claims (11)

A device that inserts an owner information logo into video content while simultaneously inserting buyer information. Means for decoding the video content; And Modifying and inserting means for changing information about the position or color value of the owner information logo to conceal the buyer information in the decoded video content, and inserting the changed owner information logo into the video content, And the owner information logo is a logo representing information about a copyright holder or a provider of the video content. The method of claim 1, The changing and inserting means, A first logo information changing scheme for representing the buyer information by changing the position of the owner information logo in the video content or between characters of text included in the owner information logo; A second logo information changing method of expressing the buyer information using a plurality of different color patterns applicable to the owner information logo, and The information on the position or the color value is changed through one or more of the third logo information changing methods of expressing the buyer information using the color values quantized at the same equidistant level with respect to the owner information logo. Buyer information insertion device. A purchaser terminal device comprising the apparatus according to claim 1 or 2. A device for extracting embedded buyer information while inserting an owner information logo into video content. Means for performing edge detection logic on the video content; And Means for obtaining a position at which a pattern of a reference logo having contour information of the owner information logo matches the pattern of the video content, for detecting a change in the information on the position or color value of the owner information logo, And the owner information logo is a logo representing information about a copyright holder or a provider of the video content. The method of claim 4, wherein Extraction of the buyer information, A first modified logo information extraction scheme for extracting the buyer information by obtaining the position of the owner information logo in the video content or the position between characters of text included in the owner information logo using the obtained matching position; A second modified logo information extraction scheme for extracting the buyer information by obtaining a color pattern applied to the owner information logo using the obtained matching position, and By using the obtained matching position, the buyer information is obtained through at least one of a third modified logo information extraction scheme which extracts the buyer information by obtaining quantized color values at the same equidistant level with respect to the owner information logo. Buyer information extraction device, characterized in that the extraction. The method of claim 4, wherein The means for obtaining the matched location may include cross correlation, mean absolute difference (MAD), or mean square error (MSE) algorithm. Extraction device. A method of inserting owner information logos into video content while simultaneously inserting buyer information. Decoding the video content; And Changing and inserting information about the position or color value of the owner information logo to conceal the buyer information in the decoded video content, and inserting the changed owner information logo into the video content, And the owner information logo is a logo representing information about a copyright holder or a provider of the video content. The method of claim 7, wherein The changing and inserting step, A first logo information changing scheme for representing the buyer information by changing the position of the owner information logo in the video content or between characters of text included in the owner information logo; A second logo information changing method of expressing the buyer information using a plurality of different color patterns applicable to the owner information logo, and The information on the position or the color value is changed through one or more of the third logo information changing methods of expressing the buyer information using the color values quantized at the same equidistant level with respect to the owner information logo. Buyer information insertion method characterized in that. A method of extracting embedded buyer information while embedding an owner information logo in video content. Performing edge detection logic on the video content; And Obtaining a position at which a pattern of a reference logo having contour information of the owner information logo matches a pattern of the video content, for detecting a change in the information on the position or color value of the owner information logo, And the owner information logo is a logo representing information about a copyright holder or a provider of the video content. The method of claim 9, Extraction of the buyer information, A first modified logo information extraction scheme for extracting the buyer information by obtaining the position of the owner information logo in the video content or the position between characters of text included in the owner information logo using the obtained matching position; A second modified logo information extraction scheme for extracting the buyer information by obtaining a color pattern applied to the owner information logo using the obtained matching position, and By using the obtained matching position, the buyer information is obtained through at least one of a third modified logo information extraction scheme which extracts the buyer information by obtaining quantized color values at the same equidistant level with respect to the owner information logo. Buyer information extraction method characterized in that the extraction. The method of claim 9, The acquiring of the matching position comprises using an algorithm of cross correlation, mean absolute difference, or mean square error.

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