KR100356201B1 - Watermarking method for copyright protection and Authentication using HSI color space - Google Patents

Abstract

The present invention relates to a watermarking technique for copyright protection using an ETS color space for a digital color video and a watermarking technique for authentication of an authorized consumer of image data.

The watermarking technique using ETS color space transforms each frame of digital color video into HSI color space and converts I (Intensity) component into frequency space to insert watermark for copyright protection. An authentication code is generated using a bitmap for authentication in the H (Hue) component. The generated authentication code is transmitted to the authorized consumer and used when checking the watermark for authentication. The watermark for copyright protection is extracted without the original image, and there is no risk of the original image being disclosed. In addition, the HSI color space is used to adapt to the human visual system rather than the RGB color space.

Description

Extraction method for extracting digital watermark from color video with watermarking and authentication technique for copyright protection and authentication technique in H.S eye color space {Watermarking method for copyright protection and Authentication using HSI color space}

The present invention relates to a watermarking and authentication method for copyright protection and an extraction method for extracting a digital watermark from a color video to which an authentication method is applied, in more detail. Watermarking technique for copyright protection using color space and digital video in color video with authentication technique for judging whether or not the image purchased by the user has been manipulated and modified by a third party. Extraction method for extracting a watermark The present invention relates to an extraction method for extracting a digital watermark from a color video to which a watermarking and authentication technique and an authentication technique for copyright protection are applied in an included ETS eye color space.

When the existing analog video content is converted to digital video content and copied, it may be indistinguishable from the original, which may cause a problem that illegally copied video content may be distributed through a network such as the Internet. ,

In order to prevent this, the existing watermarking technique for copyright protection is mainly applied to still images.

It used a technique of inserting a watermark by transforming pixel values into an image at first, but it is not robust to image processing such as noise or compression, so it converts an image into a frequency domain to insert a watermark and compares it with the original image. By using the technique of extracting watermark, it is robust to lossy compression such as JPEG.

However, the conventional watermarking method has the disadvantage that the original image is not required and the copyright itself cannot be protected by the manipulation. When the watermarking technique is applied to a video, the color difference is applied to most black and white images. There was a drawback of not considering the ingredients.

Similarly, the watermarking technique for authentication has a disadvantage that the conventional method does not consider the color difference component.

Therefore, the present invention can be applied not only to extract a watermark without an original image but also to a color video, and at the same time, it is conceived to protect legitimate consumers by applying an authentication technique.

By applying the color information of color video to HSI color space, insert watermark for copyright protection in I component and generate authentication code using H component, and transmit this code to consumers to transform the image. Its purpose is to be able to check whether or not.

As a specific means of the present invention for achieving this object;

An extraction step (S10) of dividing the watermark into a respective frame for the video to be inserted; Converting each frame into an HSI color space for embedding a watermark (S20); Extracting an I (Intensity) component of a frame to apply a watermark for claiming ownership in the converted HSI color space (S30); Determining an insertion position and an intensity of a digital watermark in the I component of the frame by obtaining a threshold using the average value of the adjacent frequency coefficient values (S40); Generating a binary code based on the threshold (S50); Generating a binary key and a bitmap according to the threshold as a new key code through an XOR operation (S60); Generating and storing a watermarked I component frame by inversely converting the watermarked frequency coefficient value (S70); Extracting an H component in each frame to apply a watermark for authentication in the HSI color space (S80); Determining a threshold for generating the authentication code (S90); Generating a binary bit string in the H component according to the generated threshold value (S100); Generating a new authentication code through an XOR operation on the binary bit string and the bitmap obtained by the threshold value (S110); Generating one frame by combining the I-color component with the watermark for the claim and the H-color component with the watermark for authentication (S120); A video generation step (S130) of combining the respective frames having the watermark embedded therein; It is achieved by having a watermarking and authentication technique for copyright protection in the HSI color space comprising the step of transmitting the watermark embedded video and the threshold used when generating the authentication code to a remote location (S140),

Receiving a color video inserted with a watermark applied to the HSI color space and a threshold used when an authentication code is generated (S150); Extracting each frame to extract a watermark for authentication and ownership claim of the color video (S160); Converting each frame into an HSI color space for watermark extraction (S170); Extracting an H component in each frame to apply watermark extraction for authentication in the HSI color space (S180); Extracting a binary code based on the threshold (S190); Extracting a bitmap for authentication from the binary code obtained by the threshold and the received authentication code through an XOR operation (S200); Extracting an I component of a frame to extract a watermark for claiming ownership in the converted HSI color space (S210); Extracting a binary code from an image according to the threshold for claiming (S220); It is achieved by having an extraction method for extracting a digital watermark from a color video to which the authentication technique, which is performed as a bitmap extraction step (S230) for claiming, is obtained through the XOR operation on the binary code obtained by the ownership keycode and the threshold value.

Here, the watermarking technique for copyright protection is applied to HSI color space for the original video, and then I component is extracted and low frequency and intermediate frequency coefficient values of I components spread through the frequency conversion such as DCT. The watermark is inserted using the value between frequencies. 3 illustrates a method of inserting a watermark using an average value of adjacent AC coefficient values by selecting a position at which a watermark is to be inserted from the remaining intermediate frequency bands excluding DC coefficients.

In the watermarking technique, since the original image is not used to extract the watermark, the watermark technique has a feature that can cope with an attack such as manipulation.

Subsequently, the watermark scheme for authentication uses a binary bit map. At this time, the size of the bitmap should be smaller than or equal to the size of the video. If small, the size of the bitmap is adjusted as much as the size of the video as shown in FIG. In the watermark for authentication, the H component of each frame is divided into two parts (0 and 1) by applying a predetermined threshold. A new binary sequence is generated by performing an XOR operation on the generated bitmap image and the binary bitmap image used for authentication. This code is used as an authentication code, which is sent to the legitimate owner through encryption or transmitted to an authorized user by applying an error control code (ECC).

1A is a general flow diagram illustrating a watermarking and authentication technique in an HT eye color space according to an embodiment of the present invention.

1B is an overall configuration diagram showing an extraction method for extracting a digital watermark from a color video to which an authentication scheme is applied.

2 is a flow chart of a watermarking technique for copyright protection on an I component of an HT eye color space according to an embodiment of the present invention.

3 is a diagram illustrating a process of inserting a watermark by selecting a position to insert a watermark for copyright protection.

4 is a diagram illustrating a process of adjusting the size of a bitmap by the size of a video.

5 is a flowchart of a watermarking technique for authentication using an H component of an HT eye color space according to an embodiment of the present invention.

FIG. 6 is a diagram illustrating an HT eye color space; FIG.

<Explanation of symbols for major parts of drawing>

Extraction step: S10 Conversion step: S20I Ingredient extraction step: S30 Insertion step: S40

Binary code generation step: S50 Key code generation step: S60 Storage step: S70

H component extraction step: S80 Threshold determination step: S90 Binary bit string generation step: S100 Authentication coat generation step: S110 Frame generation step: S120 Video generation step: S130

Transmission step: S140 threshold input step: S150 frame extraction step: S160

Conversion step: S170 H component extraction step: S180 Bitmap extraction step: S200

I component extraction step: S210 Binary code extraction step: S220 Bitmap extraction step: S230

Hereinafter, preferred embodiments of a watermarking technique and an authentication technique for copyright protection in an HSI color space according to the present invention will be described in detail with reference to the accompanying drawings.

<Example>

1 is a flowchart showing a preferred embodiment of a watermarking technique and an authentication technique for copyright protection in an HSI color space according to the present invention, and FIGS. 2 and 5 are each HSI color. A diagram illustrating a watermarking technique and an authentication technique for copyright protection in a space.

As shown therein, the watermarking and authentication method of the present invention includes an extraction step (S10) of dividing the video into respective frames; A conversion step (S20) of converting each frame into an HSI color space; An I component extraction step (S30) of extracting an I (Intensity) component of the frame to apply a watermark in the converted HSI color space; An insertion step (S40) of obtaining a threshold to determine and insert an insertion position and an intensity of the digital watermark in the I component of the frame; A binary code generation step (S50) of generating a binary code by the threshold value; A key code generation step S60 of generating a binary code and a bitmap as a new key code through an XOR operation; A storage step (S70) of generating and storing an I component frame having a watermark embedded therein by inversely converting the watermarked frequency coefficient value; An H component extracting step (S80) of extracting an H component in each frame to apply a watermark for authentication in an HSI color space; A threshold determination step (S90) of determining a threshold for generating an authentication code; A binary bit string generation step (S100) of generating a binary bit string in the H component according to the threshold value; An authentication coat generation step (S110) of generating a new authentication code through an XOR operation on the binary bit string and the bitmap obtained by the threshold value; A frame generation step (S120) of generating one frame by combining the I color component and the H color component; A video generating step (S130) of generating a video by combining the respective frames having the watermark inserted therein; Transmitting step (S140) for transmitting the threshold value used when generating the video and the authentication code to the remote.

In the frame extracting step (S10), each frame is extracted to insert a watermark from the color video. By inserting a watermark into a frame that is an uncompressed region, the watermark is more robust in watermark attacks such as image processing and geometric transformation.

Thereafter, each color frame is converted into an HSI color space (S20).

There are various color spaces, such as HSI, R / G / B, Y / Cr / Cb, for conversion of the color space. In the HSI color space, the representation of the color components in the image is different from that of the RGB color space. In the case of the RGB color space, RGB is represented by a coordinate system of each component axis, whereas the HSI color space is represented by the two cones as shown in FIG. 6 to express the HSI color space. .

This HSI color space has two big features.

First, the intensity component I is separated from the color information in the image, and second, the H component hue difference and the saturation component S are divided into RGB components. As it is close, it is suitable for inserting a watermark for color video using a human visual system.

By using Equation 1 below, the RGB component may be expressed as an HSI color component.

Thereafter, a step S30 of extracting an I component from each frame is performed to claim the watermark.

In general, the watermarking technique for copyright protection performs a step (S35) of inserting a digital watermark using a spread spectrum technique proposed by Cox et al. To improve the robustness of the watermark. This will be explained in more detail to help.

The human visual system is insensitive to high frequency components in terms of frequency but sensitive to low frequency components. Therefore, in the image compression algorithm, a compressed image is obtained by removing high frequency components rather than low frequencies. Therefore, in order to preserve the digital watermark after compression, the digital watermark must be inserted into a low frequency component that is visually sensitive to humans, and at the same time, the opposite condition that the inserted digital watermark cannot be detected by the naked eye must be satisfied. As such, a spread spectrum technique has been widely known as a method of inserting a digital watermark incapable of detecting human vision in a portion sensitive to human visual characteristics.

In the spread spectrum technique proposed by IJ Cox et al., After performing DCT (Discrete Cosine Transform) on the entire size of the original image, N coefficients (N is about 1000) are the largest among absolute coefficients except DC components. To a real number sequence consisting of N real numbers, i.e., a digital watermark.

References to the spread spectrum technique are described by I. J. Cox et al. In NEC Research Institute Technical Report and Proc. IEEE internet. Conf. Representatives of "Secure Spread Spectrum Watermarking for Multimedia" and "Secure Spread Spectrum Watermarking for Images, Audio, and Video" published on on Image Processing (ICIP'96), see further details on spread spectrum techniques. Let's do it.

On the other hand, in the preferred embodiment of the present invention has been described limited to the digital watermark embedding method by the spread spectrum technique, it is well known that any digital watermarking technique known in addition to the spread spectrum technique may be used.

Subsequently, a threshold value is calculated using an average value of adjacent frequency coefficient values and an watermark is inserted (S40). Since the threshold value is referred to when calculating the threshold value, the threshold value can be inferred from the average value of the peripheral values in the distributed image without the original image.

In this case, by inserting the watermark adaptively into the coefficient value, robustness can be maintained even if any image processing or attack is performed later.

Subsequently, a step S50 of generating a new binary code in which a value is larger than a threshold value obtained by the average value of the frequency coefficient value and a value is set to 0 is small. Even if any post-processing is performed on the image into which the watermark is inserted later, it does not have much difference from the original image, and thus does not have much difference from the original binary code.

Thereafter, a unique key code is generated through the XOR operation on the bitmap having the company logo or the distributor's information (S60). This information is held by the owner and can be used later in bitmap extraction or ownership disputes.

Subsequently, a watermark for claiming is generated in the I color component through inverse transformation of the watermarked frequency coefficient value by the spread spectrum technique (S70).

Meanwhile, a step S80 of extracting an H component from each frame is performed for a watermark technique for authentication. The authentication technique is a method for identifying the modified position and how it is transformed in the modified image when an attacker who does not own the image artificially transforms the image. Unlike claims, it should not have robustness to identify variations in the video for authentication. For reference, in order to insert a digital watermark for authentication into a digital image, the following items are required.

• Fragile: The watermark should be easily erased for minor changes to the image.

• Integrity: For any deformation of the image, it should be possible to determine the presence and location of the deformation.

Subsequently, in order to generate an authentication code for an authorized user, a threshold is determined in the image (S90) to generate a binary bit map (S100). At this time, the size of the bitmap should be smaller than or equal to the size of the video. If small, the bitmap is adjusted by the size of the video as shown in FIG. The H component per pixel is divided into two parts (0 and 1) by applying a predetermined threshold.

Thereafter, a unique code only for the authorized user is generated in operation S110 of generating a new authentication code through the XOR operation on the binary bit string and the bitmap obtained by the threshold.

A frame is formed by combining the I color component in which the watermark for ownership is inserted and the H color component in which the authentication code is generated (S120). Therefore, each frame can be simultaneously claimed and authenticated. Problems can arise when using authentication and claiming independently. When only authentication is used, the original image cannot be used in terms of authentication when it is confirmed that image data is damaged by intentional or unintentional attack. However, the damaged image is distributed to the outside and freely spread. To compensate for this, a watermark for claim can be inserted to protect the damaged original image.

Thereafter, a step (S130) of generating the video by combining the respective frames is performed.

In the final watermark embedding step (S140), the video with the watermark embedded and the threshold and authentication code used when the authentication code is generated are transmitted to the remote site together.

A process of extracting a digital watermark from a color video to which watermarking and authentication techniques for copyright protection in an HSI color space are applied through the above process will be described.

This is basically as shown in Figure 1b, the process of extracting the digital watermark is the reverse of the insertion process,

A threshold value input step (S150) of receiving a color video having a watermark applied to an HSI color space and a threshold value used when an authentication code is generated; Extracting each frame (S160) to extract a watermark for authentication and claim of color video; A conversion step (S170) of converting an HSI color space to extract a watermark of each frame; H component extraction step (S180) of extracting H components in each frame to apply watermark extraction for authentication in HSI color space; Extracting a binary code based on a threshold (S190); A bitmap extraction step (S200) of extracting a bitmap for authentication from the binary code obtained by the threshold and the received authentication code through an XOR operation; An I component extraction step (S210) of extracting I components of the frame in order to extract a watermark for claiming ownership in the converted HSI color space; A binary code extraction step (S220) of extracting a binary code from an image according to a threshold for claiming; The binary code obtained by the ownership key code and the threshold value is configured to perform a bitmap extraction step (S230) for claiming through an XOR operation.

Here, in the threshold force step (S150), the color code transmitted from the outside and an authentication code and a threshold used for authentication are received.

Then, in the digital watermark extraction method, the watermark is extracted by dividing the corresponding video to each frame (S160).

Thereafter, each frame is converted into an HSI color space for watermark extraction (S170), and H components are extracted in each frame for watermark extraction for authentication (S180).

Thereafter, the binary code is extracted by applying the received threshold (S190). The transformation of the extracted binary code plays an important role in distinguishing what manipulation or processing is performed on the received image.

Subsequently, the bitmap for authentication is extracted through the XOR operation on the binary code obtained by the threshold and the received authentication code (S200). It is not known which portion of the image is damaged when any post-intentional or intentional post-processing is performed on the color video. However, the damaged part can be found in the binary bitmap extracted through XOR, which makes the intentional attack more effective.

Subsequently, in the step of extracting the bitmap for claiming, first, an I color component in which a watermark is inserted for claiming is extracted from the frame among the HSI color components (S210).

Thereafter, frequency conversion is performed on the extracted I color component by using a spread spectrum technique (S215), and then a binary code is extracted from the threshold obtained by applying an average value of adjacent frequency coefficient values (S220). The binary code extracted from the threshold value extracts a bitmap containing the company logo or the distributor's information through a key code owned by the owner and an XOR operation (S230). When various attacks or post-processing are performed, the bitmap extracted from the image is retained in its form and can be used in ownership disputes.

There is a difference between how to get the threshold in the method for authentication and the method for claiming. In the authentication method, a unique authentication binary code is generated by arbitrarily setting one reference value in the space area. However, in the claim method, the threshold is obtained by taking the average of the values around the coefficients in the frequency domain. Equation 2 and Equation 3 may be performed to insert a watermark and to obtain a threshold value as a reference thereof.

here, Denotes the visibility or robustness of the digital watermark as a scale variable. therefore, The larger the value of, the more robust the digital watermark is, but the image quality may be reduced due to the digital watermark.

In how to suggest The experimental value was used as 0.05. If 1000 watermarks are inserted per frame _, the number of frequency coefficients of v _{(i, j)} to be inserted into the watermarks can be selected to adjust the frequency coefficients as above and make 1000 binary codes.

The present invention provides a digital watermarking technique that can simultaneously claim as well as authenticate a color video using an HSI color format. In particular, since it does not require the original image, it can be applied more effectively to a video having a lot of image data.

In the case of watermark attack, copyright protection is possible when the video is compressed, and it is also strong against attacks such as claims and engagements that other attackers claim as their own video. It also has the advantage of copyright protection for post-processing such as resizing, clipping and various filtering on images.

Terminology used in the present invention are terms defined in consideration of functions in the present invention and may vary according to the intention or custom of a person skilled in the art, and the definition should be made based on the contents throughout the present application. something to do.

In addition, since the present invention has been described through the preferred embodiment of the present invention, in view of the technical difficulty aspects of the present invention, those having ordinary skill in the art can easily and another embodiment of the present invention. Other variations can be made.

As described in detail above, the present invention converts each frame extracted from the color video into an HSI color space, so that the watermark technique for authentication in the H color space, and the claim for claims in the I color space. Is a watermark technique,

In the authentication method, a new authentication binary code is generated through XOR operation on the binary code obtained by the threshold in the bitmap and the spatial domain containing the company logo or distributor information, and in the I color space, the threshold obtained by the average value around the frequency coefficients. New binary code is generated as key code through XOR operation of binary code and bitmap applied by

The extraction process is based on the inverse process of the insertion process, i.e., in the H color component, the bitmap using XOR operation is used to extract the transmitted binary code and the binary code generated by the threshold of the spatial domain. Authentication and copyright protection for color video by inserting and extracting bitmaps through XOR operation of a binary code used as a key code and a binary code obtained by a threshold obtained by applying an average value of adjacent frequency coefficient values in a received image. Capabilities can be held at the same time, and at the same time, there is an advantage to protect legitimate consumers by applying authentication techniques.

In particular, copyright protection is possible even when the video is compressed, and it is not only strong against attacks such as claims, video editing, and collision that other attackers claim to be their own video, Even if artificial post-processing such as filtering is performed, copyright protection is possible.

Claims (6)

An extraction step (S10) of dividing the watermark into a respective frame for the video to be inserted; Converting to an HS eye color space for embedding a watermark in each frame (S20); Extracting an I (Intensity) component of the frame in order to apply a watermark for copyright claim in the converted E.S. color space (S30); Determining an insertion position and an intensity of a digital watermark in the I component of the frame by obtaining a threshold using the average value of the adjacent frequency coefficient values (S40); Generating a binary code based on the threshold (S50); Generating a binary key and a bitmap according to the threshold as a new key code through an XOR operation (S60); Generating and storing a watermarked I component frame by inversely converting the watermarked frequency coefficient value (S70); Extracting an H component in each frame to apply a watermark for authentication in the HS eye color space (S80); Determining a threshold for generating the authentication code (S90); Generating a binary bit string in the H component according to the generated threshold value (S100); Generating a new authentication code through an XOR operation on the binary bit string and the bitmap obtained by the threshold value (S110); Generating one frame by combining the I-color component with the watermark for the claim and the H-color component with the watermark for authentication (S120); A video generation step (S130) of combining the respective frames having the watermark embedded therein; Watermarking and authentication techniques for copyright protection in the HS eye color space comprising the step of transmitting the watermark embedded video and the threshold used when generating the authentication code to the remote (S140). The method according to claim 1, wherein each frame extracted from the color video is converted into an ETS color space, and a watermark for authentication is applied to the H color space, and a watermark for copyright claims is simultaneously applied to the I color space. Watermarking and authentication techniques for copyright protection in ETSI color space. The method of claim 1, wherein a binary code is generated according to an average value around a coefficient value into which the watermark is to be inserted, thereby generating a new binary code through a bitmap and an XOR operation. Watermarking and authentication techniques for copyright protection. The watermarking technique of claim 1 or 2, wherein the digital watermark is configured to be visually confirmed at the time of authentication and copyright claim using the bitmap. And authentication techniques. Receiving a color video in which a watermark applied to an HSI color space is inserted and a threshold value used when an authentication code is generated (S150); Extracting each frame to extract a watermark for authentication and copyright claim of the color video (S160); Converting each frame into an HS eye color space for watermark extraction (S170); Extracting an H component in each frame to apply watermark extraction for authentication in the HS eye color space (S180); Extracting a binary code based on the threshold (S190); Extracting a bitmap for authentication from the binary code obtained by the threshold and the received authentication code through an XOR operation (S200); Extracting an I component of a frame to extract a watermark for copyright claim from the converted E.S. color space (S210); Extracting a binary code from an image according to the threshold for claiming (S220); And extracting the digital watermark from the color video to which the authentication scheme is applied as the bitmap extraction step (S230) for claiming the copyright through the XOR operation on the binary code obtained by the ownership keycode and the threshold value. 6. The method of claim 5, wherein the H color component extracts a bitmap using XOR operation for the binary code generated by the transmitted authentication binary code and the threshold of the spatial domain. An authentication scheme is characterized in that the bitmap is inserted and extracted through XOR operation with a binary code obtained by a threshold value applying an average value of frequency coefficient values in a captured image to simultaneously hold a color video authentication and copyright protection capability. Extraction method to extract digital watermark from applied color video.