Associated information adding apparatus and method, and associated information detecting apparatus and method

• US 6,731,774 B1
• Filed: 11/30/1999
• Issued: 05/04/2004
• Est. Priority Date: 11/30/1998
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Yagasaki, Yoichi, Hosaka, Kazuhisa, Miyahara, Nobuyoshi
• Primary Examiner(s): Patel, Jayanti K.
• Assistant Examiner(s): Tabatabai, Abolfazl
• Application Number:
  US09/450,613
• Time in Patent Office: 1,617 Days
• Field of Search: 382/100, 382/232, 380/51, 380/54, 380/201, 380/210, 380/252, 380/287, 370/522, 370/523, 370/524, 370/525, 370/526, 370/527, 370/528, 370/529, 348/460, 348/461, 348/463, 713/176, 713/179, 388/94, 283/74, 283/75, 283/76, 283/77, 283/78, 283/79, 283/80, 283/81, 283/85, 283/93, 283/130, 283/901, 283/902, 704/201.1, 704/273, 705/57, 705/58
• US Class Current: 382/100
• CPC Class Codes: G06T 1/0071 using multiple or alternating watermarks
• CPC Class Codes: G06T 2201/0051 Embedding of the watermark in the spatial domain
• CPC Class Codes: G06T 2201/0061 Embedding of the watermark in each block of the image, e.g. segmented watermarking
• CPC Class Codes: G06T 9/00 Image coding bandwidth or redundancy reduction for static pictures H04N1/41; coding or decoding of static colour picture signals H04N1/64; methods or arrangements for coding, decoding, compressing or decompressing digital video signals H04N19/00

Abstract

The present invention relates to an information adding apparatus and method for adding information as a watermark to an image. Particularly, the invention is characterized in that a unit watermark pattern having a size corresponding to a small region made of vertical×horizontal=M×N (M and N are respectively a positive integer) pixels of a part of an image is generated, a repetitive watermark in which the unit watermark pattern from a unit watermark pattern generator is repeated vertically and horizontally is generated, checking is performed against the repetitive watermark, a watermark is added to the image, and in the unit watermark pattern generator, the size of the unit watermark pattern is determined such that at all resolutions expected that resolution conversion for the image is performed, each of the vertical and horizontal sizes of the unit watermark is integer times as large as a size of an encoded block at image encoding. By this, the size of the unit watermark pattern is integer times as large as the size of the encoded block at the image encoding at all resolutions expected that the resolution conversion is performed. Thus, at the time of detection of the associated information, if the resolution of image information is known, it is possible to know, at the resolution, what times as large as the encoded block the unit watermark is, and folding accumulation becomes possible in a unit of the unit watermark of an integer number of encoded blocks

Claims

1. An information detecting apparatus in which a watermark pattern and an image are checked with each other for every small region made of vertical×

horizontal=M×

N (M and N are respectively a positive integer) pixels of a part of the image, information is embedded as a watermark in the image on the basis of the watermark pattern, and the information is detected from the image constructed by applying resolution conversion or picture frame conversion to the image embedded with the information, the information detecting apparatus comprising;

arithmetic means for converting the watermark pattern correspondingly to the resolution conversion or picture frame conversion, performing checking against the watermark pattern made to correspond to at least a part of an encoded block in the image subjected to the resolution conversion or picture frame conversion, and calculating an evaluation value on the image; and

judging means for comparing the evaluation value with a predetermined threshold value and judging whether the watermark is added;

wherein the arithmetic means omits an arithmetic operation of the evaluation value in a case where a ratio of correspondence between the converted watermark pattern and the encoded block in the image subjected to the resolution conversion or picture frame conversion is smaller than a predetermined ratio.

2. An information detecting apparatus according to claim 1, wherein the arithmetic means multiplies the evaluation value by a weight in accordance with a ratio of correspondence between the converted watermark pattern and the encoded block in the image subjected to the resolution conversion or picture frame conversion.

3. An information detecting apparatus according to claim 1, wherein the image is an image subjected to letter box conversion.

4. An information detecting method in which a watermark pattern and an image are checked with each other for every small region made of vertical×

horizontal=M×

N (M and N are respectively a positive integer) pixels of a part of the image, information is embedded as a watermark in the image on the basis of the watermark pattern, and the information is detected from the image constructed by applying resolution conversion or picture frame conversion to the image embedded with the information, the information detecting method comprising the steps of;

converting the watermark pattern correspondingly to the resolution conversion or picture frame conversion;

performing checking against the watermark pattern made to correspond to at least a part of an encoded block in the image subjected to the resolution conversion or picture frame conversion;

calculating an evaluation value on the image;

comparing the evaluation value with a predetermined threshold value to judge whether the watermark is added; and

omitting an arithmetic operation of the evaluation value in a case where a ratio of correspondence between the converted watermark pattern and the encoded block in the image subjected to the resolution conversion or picture frame conversion is smaller than a predetermined ratio.

5. A providing medium for providing a computer-readable program to make an information detecting apparatus in which a watermark pattern and an image are checked with each other for every small region made of vertical×

horizontal=M×

N (M and N are respectively a positive integer) pixels of a part of the image, information is embedded as a watermark in the image on the basis of the watermark pattern, and the information is detected from the image constructed by applying resolution conversion or picture frame conversion to the image embedded with the information, to execute a process comprising the steps of;

converting the watermark pattern correspondingly to the resolution conversion or picture frame conversion;

performing checking against the watermark pattern made to correspond to at least a part of an encoded block in the image subjected to the resolution conversion or picture frame conversion;

calculating an evaluation value on the image;

comparing the evaluation value with a predetermined threshold value to judge whether the watermark is added; and

omitting an arithmetic operation of the evaluation value in a case where a ratio of correspondence between the converted watermark pattern and the encoded block in the image subjected to the resolution conversion or picture frame conversion is smaller than a predetermined ratio.

6. An information adding apparatus for adding information as a watermark to an image, comprising:

unit watermark pattern generating means for generating a unit watermark pattern having a size corresponding to a small region made of vertical×

horizontal=M×

N (M and N are respectively a positive integer) pixels of a part of the image;

watermark repeating means for generating a repetitive watermark in which the unit watermark pattern from the unit watermark pattern generating means is repeated vertically and horizontally; and

embedding means for checking the repetitive watermark and adding the watermark to the image;

wherein the unit watermark pattern generating means determines a size of the unit watermark pattern so that at all resolutions expected that resolution conversion is performed for the image, each of a vertical size and a horizontal size of the unit watermark becomes integer times as large as a size of an encoded block at image encoding.

7. An information adding method in which a repetitive watermark is added to an image, the repetitive watermark being formed by vertically and horizontally repeating a unit watermark pattern having a size corresponding to a small region made of vertical×

horizontal=M×

N (M and N are respectively a positive integer) pixels of a part of the image,

wherein a size of the unit watermark pattern is determined so that at all resolutions expected that resolution conversion is performed for the image, each of a vertical size and a horizontal size of the unit watermark becomes integer times as large as a size of an encoded block at image encoding.

8. An information adding apparatus for adding information as a watermark to an image, comprising:

unit watermark pattern generating means for generating a unit watermark pattern having a size corresponding to a small region made of vertical×

horizontal=M×

N (M and N are respectively a positive integer) pixels of a part of the image; and

watermark repeating means for generating a repetitive watermark in which the unit watermark pattern from the unit watermark pattern generating means is repeated vertically and horizontally;

wherein the unit watermark pattern generating means determines a size of the unit watermark pattern so that at a plurality of selected resolutions in all resolutions expected that resolution conversion is performed for the image, each of a vertical size and a horizontal size of the unit watermark becomes integer times as large as a size of an encoded block at image encoding.

9. An information adding method in which a repetitive watermark is added to an image, the repetitive watermark being formed by vertically and horizontally repeating a unit watermark pattern having a size corresponding to a small region made of vertical×

horizontal=M×

N (M and N are respectively a positive integer) pixels of a part of the image,

wherein a size of the unit watermark pattern is determined so that at a plurality of selected resolutions in all resolutions expected that resolution conversion is performed for the image, each of a vertical size and a horizontal size of the unit watermark becomes integer times as large as a size of an encoded block at image encoding.

10. An information detecting apparatus for detecting information from an image added with a repetitive watermark formed by vertically and horizontally repeating a unit watermark pattern having a size corresponding to a small region made of vertical×

horizontal=M×

N (M and N are respectively a positive integer) pixels of a part of the image, where in at all resolutions expected that resolution conversion is performed for the image, each of a vertical size and a horizontal size of the unit watermark pattern is made to be integer times as large as a size of an encoded block at image encoding, the information detecting apparatus comprising;

resolution converting means for converting a resolution of the image into a specific resolution;

correlation detecting means for checking a correlation between the image in which its resolution is converted by the resolution converting means and the unit watermark pattern; and

judgement means for judging whether the information is added, based on detection output of the correlation detecting means.

11. An information detecting apparatus according to claim 10, further comprising resolution ratio calculating means for calculating a ratio of resolution conversion in the resolution converting means based on information of a resolution contained in input image information;

wherein the resolution converting means executes the resolution conversion based on the resolution ratio calculated by the resolution ratio calculating means.

12. An information detecting apparatus according to claim 11, further comprising folding accumulation means for executing folding accumulation, before the resolution conversion and with respect to the image added with the repetitive watermark, in a unit of a small region corresponding to a size of the unit watermark pattern before the resolution conversion, the size being determined based on the resolution ratio from the resolution ratio calculating means and information of the size of the unit watermark pattern after the resolution conversion;

wherein the correlation detecting means checks a correlation between what is obtained by subjecting an accumulation result of the folding accumulation means to the resolution conversion by the resolution converting means and the unit watermark pattern after the resolution conversion.

13. An information detecting apparatus according to claim 12, wherein:

the input image information is compressed data using DCT (Discrete Cosine Transform);

the folding accumulation means executes the folding accumulation at a stage of a DCT coefficient of the compressed data;

a reverse DCT processing portion for executing reverse DCT processing of the accumulation result of the folding accumulation means is provided; and

output of the reverse DCT processing portion is supplied to the resolution converting means.

14. An information detecting method for detecting associated information by detecting a unit watermark pattern from an image added with a repetitive watermark in which the unit watermark pattern having a size corresponding to a small region made of vertical×

horizontal=M×

N (M and N are respectively a positive integer) pixels of a part of an image is repeated horizontally and vertically, wherein;

each of a vertical size and a horizontal size of the unit watermark pattern is made, at all resolutions expected that resolution conversion is performed for the image, to be integer times as large as a size of an encoded block at image encoding;

after the resolution of the image is converted to a specific resolution, a correlation between the image in which its resolution is converted to the specific resolution and the unit watermark pattern is checked; and

based on a result of correlation detection, it is judged whether the information is added.

15. An information detecting method according to claim 14, wherein:

a ratio of the resolution conversion is calculated based on resolution information contained in input image information; and

the resolution conversion is executed based on the calculated resolution ratio.

16. An information detecting method according to claim 15, wherein:

folding accumulation is executed, before the resolution conversion and with respect to the image added with the repetitive watermark, in a unit of a small region corresponding to a size of the unit watermark pattern before the resolution conversion, the size being determined based on the calculated resolution ratio and information of the size of the unit watermark pattern after the resolution conversion; and

a correlation between what is obtained by subjecting a folding accumulation result to the resolution conversion and the unit watermark pattern after the resolution conversion is checked.

17. An information detecting method according to claim 16, wherein:

the input image information is compression data using DCT (Discrete Cosine Transform);

the folding accumulation is executed at a stage of a DCT coefficient of the compressed data; and

what is obtained by subjecting the folding accumulation result to reverse DCT processing is subjected to the resolution conversion.

18. An information detecting apparatus for detecting associated information by detecting a unit watermark pattern from an image added with a repetitive watermark formed by vertically and horizontally repeating the unit watermark pattern having a size corresponding to a small region made of vertical×

horizontal=M×

N (M and N are respectively a positive integer) pixels of a part of the image, wherein at a plurality of selected resolutions in all resolutions expected that resolution conversion is performed for the image, each of a vertical size and a horizontal size of the unit watermark pattern is made to be integer times as large as a size of an encoded block at image encoding, the information detecting apparatus comprising;

resolution converting means for converting a resolution of the image into a specific resolution;

correlation detecting means for checking a correlation between the image in which its resolution is converted by the resolution converting means and the unit watermark pattern; and

judgment means for judging whether the information is added, based on detection output of the correlation detecting means.

19. An information detecting method for detecting associated information by detecting a unit watermark pattern from an image added with a repetitive watermark in which the unit watermark pattern having a size corresponding to a small region made of vertical×

horizontal=M×

N (M and N are respectively a positive integer) pixels of a part of an image is repeated horizontally and vertically, wherein;

each of a vertical size and a horizontal size of the unit watermark pattern is made, at a plurality of selected resolutions in all resolutions expected that resolution conversion is performed for the image, to be integer times as large as a size of an encoded block at image encoding;

after the resolution of the image is converted to a specific resolution, a correlation between the image in which its resolution is converted to the specific resolution and the unit watermark pattern is checked; and

based on a result of correlation detection, it is judged whether the information is added.