Image processing apparatus, image processing method and storage medium

• US 20020021808A1
• Filed: 05/31/2001
• Published: 02/21/2002
• Est. Priority Date: 05/31/2000
• Status: Abandoned Application

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Iwamura, Keiichi
• Application Number:
  US09/867,432
• Publication Number:
  US 20020021808A1
• Time in Patent Office: Days
• US Class Current: 380/210
• CPC Class Codes: G06T 1/005 Robust watermarking, e.g. average attack or collusion attack resistant
• CPC Class Codes: G06T 2201/0052 Embedding of the watermark in the frequency domain
• CPC Class Codes: G06T 2201/0063 in relation to collusion attacks, e.g. collusion attack resistant
• CPC Class Codes: H04N 19/63 using sub-band based transform, e.g. wavelets
• CPC Class Codes: H04N 21/8358 involving watermark protecting executable software by watermarking G06F21/16; image watermarking in general G06T1/0021; watermarks inserted in still images for transmission purposes H04N1/32144; inserting watermarks during video coding H04N19/467

Abstract

A digital watermark mark which is robust against alliance and average value attacks is embedded in data, and original data is protected from being tampered with. Image quality that may be obtained by an attacker by, e.g., an alliance attack is determined (step S301). In this case, LL3 is determined to be that image quality. A portion to be modified of high-image quality portions is determined (step S302). In this case, HL1 is determined as a high-image quality portion to be modified, and is entirely shifted rightward by 1 bit. Hence, prepared block images undergo wavelet transformation (step S303) to be decomposed into frequency components, and HL1 as the selected high-image quality portion is modified (step S304). Upon completion of the aforementioned modification process, this block undergoes inverse wavelet transformation to reclaim the block image (step S305).

Claims

1. An image processing apparatus comprising:

generation means for generating digital data which comprises a first data group required to maintain basic quality of the digital data, and a second data group required to maintain detailed quality;

change means for changing the second data group in the digital data; and

embedding means for embedding a digital watermark in the image which contains the changed second data group.

2. An image processing apparatus for embedding a digital watermark in an image, comprising:

setting means for setting a range of frequency components to be changed of frequency components of the image; and

change means for changing at least one of the frequency components included in the range of the frequency components to be changed,

wherein the digital watermark is embedded in the image which contains the frequency component changed by said change means.

3. The apparatus according to claim 2, further comprising:

frequency component calculation means for calculating frequency components of the image; and

image generation means for generating an image from frequency components of the image including the frequency component changed by said change means.

4. The apparatus according to claim 3, wherein said frequency component calculation means includes at least one of wavelet transformation and discrete cosine transformation, and said image generation means includes at least one of inverse wavelet transformation and inverse discrete cosine transformation.

5. The apparatus according to claim 2, wherein a change process of said change means includes a bit-shift process.

7. The apparatus according to claim 2, wherein a change process of said change means includes processes of four arithmetic operations.

10. The apparatus according to claim 2, wherein said change means changes for respective users.

6. An image processing apparatus for embedding a digital watermark in an image, comprising:

setting means for setting a range of bits to be changed of a plurality of bits which form a multi-valued pixel upon expressing pixels which form the image using multi-valued data; and

change means for changing at least one of bits included in the range of bits to be changed,

wherein the digital watermark is embedded in the image which includes the bit changed by said change means.

8. The apparatus according to claim 6, wherein a change process of said change means includes processes of four arithmetic operations.

9. The apparatus according to claim 6, wherein a change process of said change means includes bit inversion.

11. The apparatus according to claim 6, wherein said change means changes for respective users.

14. The method according to claim 13, further comprising:

the frequency component calculation step of calculating frequency components of the image; and

the image generation step of generating an image from frequency components of the image including the frequency component changed in the change step.

18. The medium according to claim 17, further comprising:

a program code of the frequency component calculation step of calculating frequency components of the image; and

a program code of the image generation step of generating an image from frequency components of the image including the frequency component changed in the change step.

12. An image processing method comprising:

the generation step of generating digital data which comprises a first data group required to maintain basic quality of the digital data, and a second data group required to maintain detailed quality;

the change step of changing the second data group in the digital data; and

the embedding step of embedding a digital watermark in the image which contains the changed second data group.

13. An image processing method for embedding a digital watermark in an image, comprising:

the setting step of setting a range of frequency components to be changed of frequency components of the image; and

the change step of changing at least one of the frequency components included in the range of the frequency components to be changed,

wherein the digital watermark is embedded in the image which contains the frequency component changed in the change step.

15. An image processing method for embedding a digital watermark in an image, comprising:

the setting step of setting a range of bits to be changed of a plurality of bits which form a multi-valued pixel upon expressing pixels which form the image using multi-valued data; and

the change step of changing at least one of bits included in the range of bits to be changed,

wherein the digital watermark is embedded in the image which includes the bit changed in the change step.

16. A storage medium that stores a program code which can be executed upon being loaded onto a computer, comprising:

a program code of the generation step of generating digital data which comprises a first data group required to maintain basic quality of the digital data, and a second data group required to maintain detailed quality;

a program code of the change step of changing the second data group in the digital data; and

a program code of the embedding step of embedding a digital watermark in the image which contains the changed second data group.

17. A storage medium that stores a program code which serves as an image processing apparatus for embedding a digital watermark in an image, comprising:

a program code of the setting step of setting a range of frequency components to be changed of frequency components of the image; and

a program code of the change step of changing at least one of the frequency components included in the range of the frequency components to be changed,

wherein the digital watermark is embedded in the image which contains the frequency component changed in the change step.

19. A storage medium that stores a program code which serves as an image processing apparatus for embedding a digital watermark in an image, comprising:

a program code of the setting step of setting a range of bits to be changed of a plurality of bits which form a multi-valued pixel upon expressing pixels which form the image using multi-valued data; and

a program code of the change step of changing at least one of bits included in the range of bits to be changed,

wherein the digital watermark is embedded in the image which includes the bit changed in the change step.

20. An image processing apparatus for embedding a digital watermark in an image, comprising:

generation means for segmenting pixels which form the image into blocks, and generating an average value image having average pixel values of pixels included in the blocks; and

change means for changing a value of at least one pixel of pixels included in each block,

wherein the digital watermark is embedded in an image including the pixel, the value of which is changed by said change means.

21. The apparatus according to claim 20, wherein a change process of said change means includes a process for changing pixel values to define a normal distribution from the average pixel value of pixels included in each block.

22. The apparatus according to claim 20, wherein a change process of said change means includes processes of four arithmetic operations.

24. The method according to claim 23, wherein a change process in the change step includes a process for changing pixel values to define a normal distribution from the average pixel value of pixels included in each block.

25. The method according to claim 23, wherein a change process in the change step includes processes of four arithmetic operations.

27. The medium according to claim 26, wherein a change process in the change step includes a process for changing pixel values to define a normal distribution from the average pixel value of pixels included in each block.

28. The medium according to claim 26, wherein a change process in the change step includes processes of four arithmetic operations.

23. An image processing method for embedding a digital watermark in an image, comprising:

the generation step of segmenting pixels which form the image into blocks, and generating an average value image having average pixel values of pixels included in the blocks; and

the change step of changing a value of at least one pixel of pixels included in each block,

wherein the digital watermark is embedded in an image including the pixel, the value of which is changed in the change step.

26. A computer readable storage medium that stores a program code for implementing an image process for embedding a digital watermark in an image, comprising:

a program code of the generation step of segmenting pixels which form the image into blocks, and generating an average value image having average pixel values of pixels included in the blocks; and

a program code of the change step of changing a value of at least one pixel of pixels included in each block,

wherein the digital watermark is embedded in an image including the pixel, the value of which is changed in the change step.