JP2003283801A - Apparatus and method for embedding reversible information, apparatus and method for reproducing contents, program, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain high-quality contents by restoring contents in which reversible information is embedded. <P>SOLUTION: In a method (a), first of all, contents 1 are divided into eight contents planes 1A, and bit streams on a low-order contents plane 1a therein are reversibly compressed. Next, decoded information of compressed data is written in an area 1c generated by the compression and afterwards put together with the other seven contents panes to obtain contents 1B in which reversible information such as electronic watermarking is embedded. In a method (b), the contents are divided into blocks, and data in each block are converted to a predictive error code or DCT coefficient. Next, a numerical value for each block is reversibly compressed. Decoded information of compression encoded data is written in an area 1d of each block generated by the compression and afterwards returned into state before the division into the blocks to obtain the contents 1B in which the reversible information is embedded. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an embedding device and method for embedding reversible information in content, and a content reproducing device for reproducing content in which reversible information is embedded.
The present invention relates to programs and recording media used in these devices.

[0002]

2. Description of the Related Art Conventionally, in the industry where multimedia contents such as images and voices are distributed, in order to prevent unauthorized copying of contents and protect copyright, they are embedded in digital watermark contents. There is. Figure 6
A conventional digital watermark embedding method is shown in (a) and (b).
In the method (a), first, the original content is divided into content planes (bit planes). In the case shown,
The content created by the 8-bit data is divided into eight content planes for each bit. Irreversible processing is performed on the lower one content plane from the eight content planes. Even if the low-order bit part of the content is processed, it is difficult for the eyes and ears to perceive it.
It can be digital watermark information.

The method (b) divides the entire content into a plurality of blocks, and irreversibly processes the numerical values of the portions that are difficult to perceive in the divided blocks. Eg DC
A high frequency component by T transform (discrete cosine transform), a quantization error, etc. are processed.

[0004]

However, in the conventional digital watermark embedding method described above, the embedded digital watermark is difficult to be perceived, but the deterioration of the image quality and the sound quality due to the processing is unavoidable. There were some cases where I was very interested. Also, by embedding a digital watermark, it is possible to prevent unauthorized copying of the content, but since it is irreversibly processed, the original content cannot be restored, and the user is inevitable in image and sound quality. I had to use the degraded content.

The present invention has been made in view of the above circumstances, and even if a digital watermark is embedded in the content, the reversible information embedding apparatus and method capable of restoring the original content by using a specific reproducing apparatus. It is an object of the present invention to provide a content reproduction apparatus and method, a program used in each apparatus, a recording medium in which this program is recorded, and a recording medium in which content in which reversible information is embedded is recorded.

[0006]

In order to achieve the above object, a first reversible information embedding device according to the present invention comprises:
Dividing means for dividing the content into a plurality of content planes for each bit; compression means for performing a compression process on a bit string of a content plane of a predetermined bit, for example, an arbitrary bit of the plurality of content planes; Content in which reversible information is embedded by synthesizing a writing unit that writes decryption information in an area generated by compression of the content plane, a content plane in which the decryption information is written, and the remaining content plane that is divided. And a synthesizing means for obtaining

The second reversible information embedding device according to the present invention further comprises a dividing means for dividing the content into a plurality of blocks, and a compressing means for subjecting the data of each divided block to a predetermined compression process. Writing means for writing decryption information in an area generated by the compression of each block subjected to the compression processing, and reversible information is embedded by returning each block to a state before division with respect to the content in which the decryption information is written. And an inverse conversion means for obtaining the content.

Further, the first content reproducing apparatus according to the present invention uses a dividing means for dividing the content into a compressed content and a content plane in which the decoding information is written and another content plane, and the decoding information. And a decoding means for decoding the compressed information, and a synthesizing means for synthesizing the decrypted content plane and the other content plane.

Further, the second content reproducing apparatus according to the present invention uses a dividing means for dividing the content into a plurality of blocks and a compressed code in the divided blocks by using the decoding information written in the respective blocks. Decoding means for decoding the encoded data and inverse conversion means for returning each of the decoded blocks to the state before division are provided.

In addition, the first reversible information embedding method according to the present invention divides the content into a plurality of content planes for each bit, and compresses a bit string of the content plane of any bit among the plurality of content planes. Reversible by performing a process, writing the decryption information in the area generated by the compression of the compressed content plane, and synthesizing the content plane in which the decryption information is written and the divided remaining content plane. It is intended to obtain contents in which information is embedded.

According to the second reversible information embedding method of the present invention, the content is divided into a plurality of blocks, a predetermined compression process is applied to the data of each of the divided blocks, and this compression process is performed. The decryption information is written in the area generated by the compression of each block, and the content in which the decryption information is written is returned to the state before the division so that the content in which the reversible information is embedded is obtained. It is a thing.

Further, in the first content reproducing method according to the present invention, the content is divided into compressed information, a content plane in which the decoding information is written, and another content plane, and the compression is performed using the decoding information. The decrypted information is decrypted, and the decrypted content plane and the other content plane are combined.

The second content reproducing method according to the present invention divides the content into a plurality of blocks, and decodes the compressed encoded data in the blocks using the decoding information written in each of the divided blocks. Decrypt,
The decoded blocks are returned to the state before the division.

Further, the program used in the first reversible information embedding device according to the present invention is a division process for dividing a content into a plurality of content planes for each bit, and a content plane of arbitrary bits from the plurality of content planes. Compression processing for performing the compression processing on the bit string of, the writing processing for writing the decoding information in the area generated by the compression of the compressed content plane, the content plane in which the decoding information is written, and the divided This is for causing the computer to perform a combining process of combining the remaining content planes to obtain the content in which the reversible information is embedded.

Further, the program used in the second lossless information embedding device according to the present invention performs a division process for dividing the content into a plurality of blocks and a predetermined compression process for the data of each of the divided blocks. Reversible by applying compression processing, writing processing for writing decryption information in an area generated by compression of each compression-processed block, and returning each block to a state before division with respect to the content in which the decryption information is written. This is for causing a computer to execute an inverse conversion process for obtaining the content in which the target information is embedded.

Further, the program used in the first content reproduction apparatus according to the present invention comprises a division process for dividing the content into a content plane in which compressed information and its decoding information are written and another content plane,
It is for causing a computer to execute a decoding process of decoding the compressed information using the decoding information and a combining process of combining the decoded content plane and the other content plane.

Also, the program used in the second content reproducing apparatus according to the present invention uses a division process for dividing the content into a plurality of blocks, and decoding information written in each of the divided blocks in the block. This is for causing a computer to execute a decoding process of decoding the compressed encoded data and an inverse conversion process of returning each of the decoded blocks to a state before division.

A recording medium on which the program according to the present invention is recorded is a recording medium on which the program used in the first reversible information embedding device is recorded.

The recording medium according to the present invention is the second recording medium.
The program used in the reversible information embedding device is recorded.

The recording medium according to the present invention is the first
The program used in the content reproduction device is recorded.

The recording medium according to the present invention is the second recording medium.
The program used in the content reproduction device is recorded.

Also, in the recording medium according to the present invention, a bit string of a content plane of arbitrary bits in a plurality of content planes divided for each bit is compressed and decoding information is written in a part of the area. It is a recorded content in which reversible information is embedded.

Further, in the recording medium according to the present invention, the data of each block divided into a plurality of blocks is subjected to compression processing, and the decoding information is written in a partial area of each block. It is a record of the content in which the target information is embedded.

[0024]

Therefore, according to the first reversible information embedding device and method of the present invention, the content is divided into the content planes, and the bit string of the content plane of the arbitrary bits is compressed, and the area generated by the compression is compressed. By writing the decryption information and then synthesizing it with another content plane, it is possible to obtain content in which the compressed portion is reversible information.

Further, according to the second reversible information embedding apparatus and method of the present invention, the content is divided into a plurality of blocks, the data of each block is compressed, and the area generated by the compression of each block is decoded. After writing the information, by returning each block to the state before the division, it is possible to obtain a content in which the compressed portion of each block is reversible information such as a digital watermark.

Further, according to the first content reproducing apparatus and method of the present invention, the content is divided into the content planes, and the compressed information and the content plane in which the decoding information is written are used by using the decoding information. After decoding, the content is combined with other content planes to reproduce the content in which the reversible information is embedded by the first reversible information embedding device and method and restore the original content.

Further, according to the second content reproducing apparatus and method of the present invention, the content is divided into a plurality of blocks and the decoding information written in each block is used to obtain the compressed encoded data in the block. After decoding, each block is returned to the state before the division, whereby the content in which the reversible information is embedded by the second reversible information embedding device and method can be reproduced to restore the original content. .

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1A and 1B are configuration diagrams showing a reversible information embedding method according to the first and second embodiments of the present invention. The first embodiment of (a) will be described. First, the original content 1 is divided bit by bit, for example, 8 content planes (bit planes)
You get 1A. The lower content plane 1a is selected from the content plane 1A, and the bit string is subjected to reversible compression processing. The compressed content plane 1b has a blank area 1c due to the data being compressed and the information being reduced. This area 1c
Decoding information for decoding the compressed data is written in. Next, the content plane 1b in which the decryption information is written is returned to the other seven content planes, and then the eight content planes are combined to remove, for example, a characteristic similar to a digital watermark. It is possible to obtain the content 1B in which possible reversible information is embedded.

Therefore, since the content 1B has been subjected to compression processing for a certain arbitrary bit portion, when the user reproduces the content 1B as it is by using a general-purpose reproduction terminal, the content can be understood to some extent. Since the quality is deteriorated in the compressed part, it can be digital watermark information. In addition, if the user reproduces the content 1B in which the reversible information as the digital watermark is embedded by using a dedicated reproduction terminal that can use the decryption information written in the area 1c of the content plane 1b, it is compressed. The data is decrypted and the original content 1 can be restored.

Next, the second embodiment of FIG. 1B will be described. First, the original content 1 is subjected to a specific dimension conversion process such as DCT on the content divided into blocks of arbitrary size,
This content 1 is divided for each arbitrary frequency. Next, the data of each block of the block-divided content 1C is subjected to a reversible conversion process for converting into a prediction error code, a DCT transform coefficient, etc. by a predetermined compression encoding method. Next, a reversible compression process according to the compression encoding method is performed on the converted numerical value of each block of the content 1D. As a result, an area 1d in which information is reduced by compression is generated in each block. Decoding information for decoding the compressed encoded data is written in this area 1d. Next, the content 1E in which the decryption information is written in the area 1d of each block is subjected to a conversion process reverse to the above-described dimension conversion process, and is returned to the state before the block division, so that the content 1B embedded with the digital watermark is obtained. obtain.

Therefore, the compressed portion of the data in the content 1B in which the reversible information such as the digital watermark is embedded becomes the digital watermark information. Further, since the blocks are divided and then compressed, the contents of this content can be understood to some extent when reproduced by a general-purpose reproducing device. Also, if the reproduction is performed by a dedicated reproduction terminal, the compressed data can be decrypted using the decryption information, and the original content 1 can be restored.

FIG. 2A is a block diagram showing an apparatus for executing the reversible information embedding method according to the first embodiment. In the figure, first, the content plane division unit 11 divides the content 1 into eight content planes 1A. The compression unit 12 uses the content plane 1
By extracting the low-order bit plane 1a from A and performing reversible compression processing, a content plane having the area 1c is obtained. Next, the decryption information writing unit 13 writes the decryption information of the compressed data in the area 1c. Next, in the synthesizing unit 14, the reversible information such as a digital watermark is embedded by synthesizing the content 1b in which the decryption information is written and the other seven content planes divided by the content plane dividing unit 11. The obtained content 1B is obtained.

FIG. 2B is a block diagram showing an apparatus for executing the reversible information embedding method according to the second embodiment. First, the block dividing unit 21 performs dimension conversion processing for dividing the original content 1 into a plurality of blocks. Next, the prediction error code for the data of each block of the content 1C divided into blocks by the conversion unit 22,
Processing for converting into a DCT conversion coefficient or the like is performed. Next, the compression unit 23 performs a reversible compression process using a predetermined compression encoding method on the converted numerical value of each block of the content 1D. Next, in the area 1d where the information is reduced by the compression generated in each block by the decryption information writing unit 24,
The decoding information for decoding the compressed coded data is written. Next, the inverse transform unit 25 causes the area 1 of each block
By returning the content 1E in which the decoding information is written to d to the state before the block division, the content 1B in which the reversible information used as a digital watermark or the like is embedded is obtained.

Next, a restoration method (content reproduction method) for restoring the original content 1 by restoring the content 1B in which the digital watermark is embedded by the reversible information embedding method according to the first embodiment will be described with reference to FIG. This will be described with reference to a). In the figure, a content 1B in which a digital watermark is embedded is divided into eight content planes, and a content plane 1b of an arbitrary bit in which reversible information such as digital watermark information is embedded is extracted from the content plane, and the area 1c is obtained. The decryption information written in is extracted.
Next, using the decryption information, the compressed data of the content 1b is expanded and decrypted. Next, the original content 1 can be obtained by synthesizing the content plane 1a having the decrypted data with the other seven content planes.

Next, the reversible information embedding method according to the second embodiment has a property similar to that of a digital watermark.
A method of restoring the content 1B in which the removable reversible information is embedded to obtain the original content 1 will be described with reference to FIG. In the figure, first, the content 1B in which a digital watermark is embedded is divided into blocks. Next, the decryption information written in the area 1d is extracted from each block of the block-divided content 1E. Next, using this decryption information, the compressed data of the content 1E is expanded and decrypted. Next, the original content 1 can be obtained by performing an inverse conversion process on the decrypted contents to restore the state before the block division.

FIG. 4A is a block diagram showing a content reproducing apparatus for executing the restoration method of FIG. 3A.
In the figure, the content plane dividing unit 31 divides the content 1B in which the digital watermark is embedded into eight content planes. Next, the decryption information extraction unit 32 extracts the low-order bit content plane 1b in which the electronic watermark information is embedded from the divided content planes, and extracts the decryption information written in the area 1c. Next, using this decoding information, the decoding unit 3
3, the compressed data of the content 1b is expanded and decoded. Next, the original content 1 can be obtained by synthesizing the content plane 1a decrypted by the synthesizing unit 34 with the other seven content planes.

FIG. 4B is a block diagram showing a content reproducing apparatus for executing the restoration method of FIG. 3B.
In the figure, first, the block division unit 41 divides the content 1B in which a digital watermark is embedded into blocks. Next, the decryption information extraction unit 42 extracts the decryption information written in the area 1d from each block of the content 1E divided into blocks. Next, the decryption unit 43 uses this decryption information to decompress and decrypt the compressed data of the content 1E. Next, the original content 1 can be obtained by returning the content decrypted by the inverse conversion unit 44 to the state before the block division.

FIG. 5 is a block diagram showing a schematic configuration of a system for embedding a digital watermark in a content and reproducing a content embedded with a digital watermark according to an embodiment of the present invention. In FIG. 5, a digital watermark and its decoding information (decoding information) are embedded in content 1 to obtain content 1B in which the digital watermark is embedded. The content user uses the detection program decoder 50 to detect the decode information for the content 1B obtained using the playback terminal, as described above. next,
As described above, the decoding process is performed using the above decoding information, and the compressed data is decompressed, so that the original content 1
Can be obtained.

Next, a program according to the embodiment of the present invention will be described. When the embedding device for reversible information such as a digital watermark and the content reproducing device according to the first and second embodiments described above are respectively configured by computer systems, respective processing units configuring the respective devices shown in FIGS. 2 and 4. A program for the CPU of each computer to execute the above-described processing according to the above constitutes a program according to the present invention.

A recording medium for recording this program constitutes the recording medium according to the present invention. Further, the reversible information embedding device and the recording medium in which the reversible information is embedded by the method according to the present invention also constitute the recording medium according to the present invention. As this recording medium, a magneto-optical disk, an optical disk, a semiconductor memory, a magnetic recording medium, or the like can be used, and these are ROM, RAM, CD.
-It may be configured and used as a ROM, a flexible disk, a memory card, or the like. In addition, this recording medium holds the program for a certain period of time like a volatile memory such as a RAM in a computer system that serves as a server or a client when the program is transmitted via a network such as the Internet or a communication line such as a telephone line. It includes things to do.

The program may be transmitted from a computer system that stores the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium.
The transmission medium is a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.

Further, the program may be for realizing a part of the functions described above. Further, it may be a so-called difference file (difference program) that can realize the above-mentioned functions in combination with a program already recorded in the computer system.

Therefore, by using this recording medium in a system or apparatus different from the system or apparatus shown in FIGS. 2 and 4, and the computer of the system or apparatus executes the program stored in this recording medium,
It is possible to obtain the same functions and effects as the functions and effects described in each embodiment, and it is possible to achieve the object of the present invention.

Further, since the reversible information can be embedded in any bit, it can be mainly used as a digital watermark when embedded in a low-order bit plane, and can be embedded in a high-order bit or a plurality of bits. If embedded in the plane, it can be used as a scramble function to prevent unauthorized browsing.

[0045]

As described above, the content in which the reversible information is embedded by the reversible information embedding device and method according to the present invention has certain conversion such as content plane division and block division when the reversible information is embedded. Since it is embedded after applying, it is possible to make the embedding method difficult to understand.

Further, by using a dedicated content reproducing apparatus for the content in which the reversible information is embedded according to the present invention, the reversible information can be completely removed without giving information from the outside, and a high quality image or sound can be obtained. Can be obtained. Further, when the content is reproduced by using a general-purpose content reproducing apparatus, the content can be roughly grasped, but the content cannot be practically used without being deteriorated. In addition, since the deterioration caused by the reversible information embedding extends to the entire content instead of a part, it is possible to prevent illegal copying.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a reversible information embedding method according to first and second embodiments of the present invention.

FIG. 2 is a configuration diagram showing a reversible information embedding device according to first and second embodiments of the present invention.

FIG. 3 is a configuration diagram showing a content reproduction method according to the first and second embodiments of the present invention.

FIG. 4 is a configuration diagram showing a content reproduction device according to first and second embodiments of the present invention.

FIG. 5 is a block diagram showing a schematic configuration of a system for reversibly embedding information and reproducing content according to the present invention.

FIG. 6 is a configuration diagram showing a conventional digital watermark embedding method.

[Explanation of symbols]

1 content 1A divided content plane 1a Lower content plane 1b Compressed content plane 1c Margin area generated by compression 1B Content with reversible information embedded Content divided into 1C blocks Margin area created by 1d compression 1E Content with decryption information written 11, 31 Content plane division unit 12, 23 Compressor 13, 24 Decryption information writing unit 14, 34 Synthesis Department 21, 41 Block division 22 Converter 25,44 Inverse conversion unit 32, 42 Decryption information extraction unit 33, 43 Decoding section 50 detection program decoder

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04N 7/24 F term (reference) 5B057 CB19 CE08 CE20 CG07 5C053 FA13 GA11 GB22 5C059 KK43 MA21 MA31 RB02 RC35 SS11 SS20 UA02 UA05 UA38 5C063 AA01 AB03 AB07 AC01 AC05 CA23 CA29 CA36 DA07 DA13 DB10 5C076 AA14 BA06

Claims (18)

[Claims] 1. A dividing unit that divides a content into a plurality of content planes for each bit, a compression unit that performs a compression process on a bit string of a content plane of an arbitrary bit of the plurality of content planes, and the compression process. Writing means for writing the decryption information into the area generated by the compression of the compressed content plane, the content plane in which the decryption information has been written and the remaining content planes that have been divided are combined, and reversible information is embedded. A reversible information embedding device comprising: a synthesizing unit for obtaining contents. 2. A division means for dividing the content into a plurality of blocks, a compression means for performing a predetermined compression process on the data of each of the divided blocks, and a compression means for compressing each of the compressed blocks. A writing means for writing the decryption information in the area and an inverse conversion means for obtaining the content in which the reversible information is embedded by returning each block to the state before the division for the content in which the decryption information is written are provided. A reversible information embedding device characterized by: 3. A dividing unit that divides the content into compressed information, a content plane in which the decoding information is written, and another content plane, and a decoding unit that decodes the compressed information using the decoding information. And a synthesizing means for synthesizing the decrypted content plane and the other content plane. 4. Dividing means for dividing the content into a plurality of blocks, decoding means for decoding compressed coded data in the divided blocks using decoding information written in the divided blocks, and the decoding A content reproducing apparatus, comprising: an inverse conversion unit for returning each of the generated blocks to a state before division. 5. A content is divided into a plurality of content planes for each bit, a bit string of a content plane of an arbitrary bit among the plurality of content planes is compressed, and the compressed content plane is compressed. Write decryption information in the area generated by
A reversible information embedding method characterized in that a content in which reversible information is embedded is obtained by synthesizing a content plane in which the decryption information is written and the remaining content planes that have been divided. 6. The content is divided into a plurality of blocks,
A predetermined compression process is applied to the data of each of the divided blocks, the decryption information is written in the area generated by the compression of each of the compression-processed blocks, and each block is added to the content in which the decryption information is written. A reversible information embedding method characterized in that a content in which reversible information is embedded is obtained by returning the data to the state before division. 7. The content is divided into a compressed information, a content plane in which the decryption information is written, and another content plane, the compressed information is decrypted using the decryption information, and the decrypted content is obtained. A content reproducing method characterized by synthesizing a plane and the other content plane. 8. The content is divided into a plurality of blocks,
A content reproducing method characterized by decoding compressed coded data in a block using the decoding information written in each of the divided blocks and returning each decoded block to a state before the division. 9. A division process of dividing a content into a plurality of content planes for each bit, a compression process of performing a compression process on a bit string of a content plane of arbitrary bits from the plurality of content planes, and the compression process. And a reversible information is embedded by combining the writing process of writing the decryption information into the area generated by the compression of the content plane, the content plane in which the decryption information is written, and the remaining divided content plane. A program for causing a computer to execute a synthesizing process for obtaining contents. 10. A division process for dividing a content into a plurality of blocks, a compression process for applying a predetermined compression process to data of each of the divided blocks, and a compression process for each of the compressed blocks. A writing process for writing the decryption information in the area and an inverse conversion process for obtaining the content in which the reversible information is embedded by returning each block to the state before the division for the content in which the decryption information is written are performed on the computer. A program to run. 11. A division process for dividing a content into compressed information, a content plane in which the decryption information is written, and another content plane, and a decryption process for decrypting the compressed information using the decryption information. And a program for causing a computer to execute a synthesizing process of synthesizing the decrypted content plane and the other content plane. 12. A division process of dividing a content into a plurality of blocks, a decoding process of decoding compressed coded data in the block using the decoding information written in each of the divided blocks, and the decoding process. A program for causing a computer to execute an inverse conversion process for returning each block that has been created to the state before division. 13. A recording medium on which the program according to claim 9 is recorded. 14. A recording medium on which the program according to claim 10 is recorded. 15. A recording medium on which the program according to claim 11 is recorded. 16. A recording medium recording the program according to claim 12. 17. A bit string of a content plane of arbitrary bits in a plurality of content planes divided for each bit is compressed and reversible information in which decoding information is written is embedded in a part of the area. Recording medium on which the recorded content is recorded. 18. The compression processing is performed on the data of each block divided into a plurality of blocks, and the reversible information in which the decoding information is written is embedded in a partial area of each block. A recording medium that records content.