KR20080069890A - A protected image service system which supports differential qualities according to user service level - Google Patents

Abstract

A protected image service system for providing a differential image quality according to a user service level and a method thereof are provided to spread digital contents by using the image contents of a low quality with a conventional image viewer without installing an additional software. A protected image service system for providing a differential image quality according to a user service level includes a protected image service management block(600), and a user system block(700). The protected image service management block generates image information through an image process for compression from original image data, and separates the image information into low quality image information which is spread without a charge and high quality image information which is implemented by a request of a user. The high quality image information is encrypted through image information encryption and a user right indiction block(640). A protected image generation block(650) stores low quality image information as a standard image format. The user system block receives a protected image from the protected image service block, and reads the low quality image through a conventional image viewer without installing additional software.

Description

A protected image service system which supports differential qualities according to user service level}

 1 is a structural diagram of a JPEG image data compression processing scheme through DCT conversion;

 2 is a structural diagram of how an image data block generated in an image compression process is stored in a file;

 3 is a structure diagram of a digital rights management system (DRM) that securely manages / protects digital content and controls / controls the use of digital content in accordance with authorized information.

 4 is a structural diagram showing a state in which an image storage format according to the present invention is separated into low quality image information and high quality image information, and a high quality image is encrypted to be stored at the back of the low quality image.

 5 is a structural diagram showing a storage format of an encrypted high quality image according to the present invention;

 6 is a structure diagram of a protected image service system providing differential image quality according to a service grade of a user according to the present invention.

 7 is a structural diagram showing a process in which a protected image is viewed as a low quality or high quality image according to the present invention;

<Description of the symbols for the main parts of the drawings>

200: Original image consisting of groups of 8 * 8 pixelblocks

210: A set of 64 DC, AC coefficients generated by DCT conversion from the original image

220: standard image storage format

230: DC coefficient value storage location

240: storage location of AC coefficients

400: Save format for protected AC values

410: DRM header for protected AC values

420: storage location of encrypted AC values by quality level

430: Storage location for low quality image AC values excluding AC values for high quality images in standard image formats

440: Protected image storage format

510: Information storage location for key value encrypted AC values for high quality image step by step

520: storage location for encrypted high-quality image AC values

600: protected image service management block

610: High quality image source

620: image information encoding block

630: encoded high quality image information

640: Image information encryption and usage rights assignment block

650: protected image generation block

660: Archive protected image information and usage rights

670: protected image service block

680: encoded low quality image information

700: user system blocks

710: user interface block

720: Request and receive block of right and high quality image information

730: Image information decryption and usage right check block

740: image information decoding block

750: Image Information Synthesizer Block

790 network

810: low quality images

820: High Quality Original Image

830: standard image viewer

Recently, due to the rapid development of IT technology, many kinds of digital contents such as image, audio, video, e-book are being distributed. Although digital content has greatly improved the accessibility and usability of the content by overcoming the time and space constraints, social dysfunction due to the infringement of intellectual property rights has been a problem. Many content owners require stronger copyright law revisions to protect their intellectual property rights and use DRM (Digital Rights Management) as an active protection measure. DRM is a technical mechanism to securely and systematically manage the rights to digital assets, providing a variety of content trading and distribution infrastructure.

However, since many commercially available DRM technologies are implemented based on encryption technology, in order to use the contents packaged with DRM, the content can only be used by obtaining a license containing the key and the right information for decryption of the content. Therefore, the user is required to pay an appropriate cost to obtain a license, there is a problem that the user has to pay the license fee in advance without checking the contents of the content. For this reason, many content providers display content that can be used in the form of previews along with a description of the content. However, since the content provided in the preview is provided only a part of the content of the entire content, there is still a problem of prepayment for the portion other than the preview content.

In case of image contents, thumbnail images are used for display of contents for internet sales, and search and contents checking function is provided using them, but the image size is small due to the low resolution. Since it is impossible to check in detail, the problem of checking the original after prepayment is not solved. This type of business also has a burden for content providers to manage multiple versions, such as thumbnails, Internet distributions, and original editions.

Accordingly, the present invention has been made to solve the above problems in the image content providing system, the object of which is to generate a low quality image from the image data block generated in the compression process of the original image to service the protected image content The first-level image data is stored in the original image compression format in plain text form by separating the first-level image data from the second-level or N-level image data capable of generating high quality images, and the low-quality image data by encrypting the two or more image data. By storing it later, if a user with a free, first-level image correctly understands the content of the image and then requests the server a high-quality original image, the server has the right to use encrypted second- or N-level image information. To provide step 1 and the remaining steps It is to provide a system that generates a high-quality original image through the synthesis of image information of.

In one aspect of the present invention, to provide a differentiated quality image according to the user's service grade in the aspect of the present invention for achieving the above object, low quality from the image data block generated in the compression process of the original image Extracting some image data that can generate an image and generating the first level image information, storing the first level image information in the conventional image format in plain text form, and storing the remaining image data except the first level image information. A process of dividing into stage or N stage image information, creating a protected image content by encrypting the stage 2 or N stage image information and storing it later in the stage 1 image information, and stage 1 of the protected image content Image information can be stored in the existing image viewer without any license. Process of making it available through the process, obtaining image rights information of the encrypted second level or N level image information from the 'protected image service system' by the 'image user system', and 'image user' The system 'decrypts the encrypted two-stage or N-stage image information using the right information, and the' image user system 'synthesizes the decrypted two-stage or N-stage image information into the plain text form of the one-stage image information. A process of reproducing high quality original image is performed.

Similar to the present invention, there is provided a 'protection method and apparatus for scalable video encoded content' (Application No.:10-2006-0030479) and 'Scalable, error-resilient DRM for scalable media' (Application No.:10). -2004-0022161), but these inventions are all related to an encryption method for differential quality of MPEG-4 video format, and the differential image using the high quality information and the low quality information of the DCT coefficient mentioned in the present invention. It is different from the provided service system.

In addition, as a similar invention in Korea, 'image display device for each grade' (Application No .: Sec. 1996-043817), 'Encoding technique and device using correlation between blocks' (Application No .: Sec. 1996-077895), and 'Video signal recording and reproducing apparatus' 'Viewing method of management' (Application No.:10-1998-008251), 'Image encoding and transmission method using data segmentation technique' (Application No.:10-2000-073695), 'Image data processing device capable of encrypting image data '(Application No.:10-2001-063045),' Encryption and Decryption Device and Method of Image Data '(Application No.:10-2002-040807),' Image Format Conversion Method with Low Image Distortion '(Application No.:10 -2004-064194), 'Network Adaptive Encryption Method and Apparatus for Digital Content Security based on DCT' (Application No.:10-2005-036320), but all of them are simple data protection methods that encrypt specific parts of data. Or differentiated images with regard to efficiency There are both different from the present invention, there is provided a service to.

Hereinafter, a plurality of embodiments of the present invention may exist, and a preferred embodiment will be described in detail with reference to the accompanying drawings. Those skilled in the art will appreciate the objects, features and advantages of the present invention through this embodiment.

1 is a structural diagram of a JPEG method using a discrete cosine transform (DCT) transform as a method of compressing image data, which will be well understood by those skilled in the art. DCT is a method that removes the correlation of data through 2D axis transformation and divides the image into blocks and converts each block according to DCT formula. Through DCT conversion, the image is separated into low and high frequency components, where low frequency means little difference from neighboring pixels, and high frequency means that there is a large difference in brightness or color of neighboring pixels. In the case of a normal image statistically, since there are many low frequencies rather than high frequencies, when the image is decomposed by frequency, the values are concentrated at low frequencies, and since they are rarely present at high frequencies, ignoring high frequencies having a small value does not affect the images. It is DCT that compression is performed using this characteristic. Using this DCT, the image can be transformed from the spatial domain to the frequency domain. Since the image data is small, the low frequency, especially the zero frequency (DC, direct current) component has a large value and the high frequency component is relatively Because of the low value, most of the information is driven to the lower frequency, so if the quantization process is performed properly, excellent image quality can be obtained with high compression ratio (clear MPEG-2, 55p-56p, Hongneung Science Press).

FIG. 2 is a conceptual diagram of a method of storing image data blocks generated in an image compression process through DCT conversion in a file. First, the input image 200 is divided into a plurality of 8 * 8 size blocks. Each 8 * 8 image block is then computed by 64 coefficients through a discrete cosine transform (DCT), each divided into a direct current (DC) component and an alternating current (AC) component (210). Is again quantized by the quantization table. The high frequency DC coefficient is then coded by differential pulse code modulation (DPCM) and the low frequency component AC coefficient is variable length coding using Huffman coding and run length coding after zigzag scanning. Are encoded. Each block, which has been compressed through encoding, is divided into a DC region 230 and an AC region 240 in a JPEG file, respectively, and stored in a 'standard image storage format' 220. In this case, some information of the high frequency component having a small value in the AC component may be ignored in order to increase compression efficiency. The AC component 240 is a high frequency component having a smaller value toward the lower right of the 64 DCT coefficient values 210. . Accordingly, if some of the AC values that follow are not stored in the sequence, the compression efficiency of the data can be improved, but only an image of lower quality than the original image can be restored.

3 is a structural diagram of a DRM (Digital Rights Management) system that securely manages / protects high quality image information and controls / controls usage according to authorized rights information, which will be well understood by those skilled in the art. . The basic structure of the DRM system is composed of three elements, 'content provider', 'content user' and 'DRM server' as shown in FIG. 3. The content provider encrypts the content using the 'DRM packager' and stores the right information. The content user controls the use of the content according to the usage right through the 'DRM client'. The DRM server issues and manages usage rights (licenses) for the encrypted content. In the present invention, high-quality image information is protected using DRM technology and the usage rights are controlled.

Figure 4 removes some high quality AC information from the conventionally stored 'standard image storage format' 220 according to the present invention, encrypts the removed information and adds it to the back of the 'standard image storage format' to store the 'protected image'. It is a conceptual diagram showing the appearance of the format '(440). The AC values of the low quality AC data storage area 430 in the 'protected image storage format' 440 are different from some of the low quality AC data storage area 240 in the conventional 'standard image storage format' 220. It only stores information. The high quality AC information is encrypted via a DRM package (Image Information Encryption and Rights Assignment Block, 640) and stored at 400 behind the normal standard image format. At this time, the encrypted high quality image information may be stored in several stages according to the grade of quality. For example, if there are 8 pieces of high quality image information separated from the AC information of a normal image format, two from the front When separated and grouped, high quality image information of 4 grades can be obtained. At this time, the degree of quality becomes more high quality information toward the back part.

5 is a conceptual diagram showing a storage format for a high quality image encrypted later in the 'protected image storage format' 440, wherein each step of the encrypted high quality image information block includes a key value and a conventional 'standard image storage format' 220 Show that the encryption values are stored for high quality AC information separated from.

6 illustrates a system architecture diagram for a protected image service system that provides differentiated image quality according to a service class of a user according to the present invention.

The protected image service management block 600 generates image information through image processing for compression from the image source data 610 and 'low quality image information' 680 for free distribution among the information. According to the user's request, it is divided into 'high quality image information' 630 to be further serviced. The high quality image information is encrypted and protected by the 'Image Information Encryption and Rights Assignment Block' 640, and the 'Protected Image Generation Block' 650 stores and encrypts the low quality image information in a standard image format. The high quality image information generated is added later in the standard image format to create a 'protected image storage format' 440. The device used in the image information encoding block 620 may use the JPEG encoding technique described above, and the device used in the image information encryption and usage right assignment block may use the DRM technique described above. . The protected image storage format 440 is stored in the encrypted image information and usage rights archive 660.

In the 'user system block' 700, a 'protected image' is provided for free from the 'protected image service block' 150 and many existing commercialized image viewers (image information decoding block, 740) are installed without installing additional software. ) Can be used to view low quality images (users can also provide protected images via a separate means such as CD or e-mail). If the user wants a higher quality image, the user may request the use right from the 'protected image service block' 670 through the 'right to use and request and receive high quality image information' 720. At this time, the location of the 'protected image service block' and the information on the high quality image are obtained from the 'DRM Header' 400 of the 'protected image storage format' 440. Subsequently, the requested 'protected image service block' 670 finds the location of the corresponding high quality image information in the 'protected image information and license archive' 660 and finds the right to use the 'license and high quality image information'. Request and reception block '720.

In the user's system, high quality image information is obtained encrypted from the back of the 'protected image storage format' 440 that the user already has and the right to use through the 'Image Information Decryption and Rights Check Block' 730. After the inspection, the data is decoded and transferred to the 'image information decoding block' 740. The decoded high quality image information is synthesized with the low quality image information through the 'image information synthesizer block' 750 to restore the 'high quality original image' 820.

7 shows that the 'protected image storage format' 440 can be used without a right to use a low quality image through an existing standard image viewer, and can be used after obtaining a right to use a high quality image. The 'standard image viewer' 830 is a program having a standard 'image information decoding block' 740 function, and refers to a general image viewer. Since the protected image storage format 440 stores the low quality image in the standard image format, the standard image viewers ignore the encrypted information added later and process only the standard format that they recognize. Therefore, low-quality images can be viewed only with a standard image viewer without installing a separate software for DRM processing.

As described above, a system for providing a protected image content providing a differentiated image quality according to a service grade of a user according to the present invention may be made. Meanwhile, in the above description of the present invention, specific embodiments have been described. This may be practiced without departing from the scope of the present invention. Therefore, the scope of the present invention should not be defined by the described embodiments, but by the equivalents of the claims and claims.

As described above, the present invention allows users to use the entire low-quality original image free of charge, so that the contents of the image content, which are often generated in a business form such as a preview or a thumbnail, in order to serve the protected image content, There is an effect that can solve the problem of 'user dissatisfaction with prepaid payment' without checking. In addition, since the 'protected image' itself includes free content for low quality, it can reduce the burden of managing a separate image, such as making an image for promotion by a content service company.

Another effect of the present invention is that many Internet users who do not want to pay for the use of digital content can use it for free in many commercially available image viewers without installing additional software for low quality image content. Can contribute to diffusion.

Claims (12)

       In the image service system, data that can generate low quality images and data that can generate high quality images are separated from the image data blocks generated during the compression of the original image. Protected image contents service method characterized by 'image service system' and 'image user system' The method of claim 1, further comprising: extracting some image data capable of generating a low quality image and generating the first level image information, and dividing the high quality image data except the first level image information into the second level image information. Image content service method The method of claim 2, wherein the high quality two-stage image information is further subdivided into one or more stages. The protected image contents according to claim 1, wherein the low quality image information is stored in a standard image format of a plain text, and the high quality image information is encrypted to be physically added to the back of the low quality image format of a plain text. Service way 5. The method of claim 4, wherein the high quality image information is divided into one or more steps according to the degree of image quality and stored in an encrypted manner. 6. The method of claim 5, wherein the one or more high quality image informations are encrypted with different keys. The protected image contents service method according to claim 4, wherein the existing image viewers do not malfunction in processing low quality images of plain text due to the added high quality image information. The method of claim 1, wherein the low quality image information is made available to a user through a standard image viewer without a separate right to use. According to claim 1, when a user wants to view a high quality image, the user can request the image service system to issue right information on the high quality image information, and can view the high quality image after issuing it from the image service system. Protected image content service method characterized by the process The protected image contents service method of claim 9, wherein the 'image service system' is a process of issuing rights information that can use differential image quality according to a user's authority level. 10. The method of claim 9, wherein the 'image user system' decrypts the encrypted high quality image information using the right information. 10. The method of claim 9, wherein the image user system synthesizes the decoded high quality image information into the low quality image information to reproduce a high quality original image.

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