Image processing apparatus for embedding information with a noise-multiplexed distribution, and method, computer program, and computer-readable storage medium therefor

• US 7,269,273 B2
• Filed: 06/23/2003
• Issued: 09/11/2007
• Est. Priority Date: 06/28/2002
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Murakami, Tomochika
• Primary Examiner(s): LAROSE, COLIN M
• Application Number:
  US10/600,533
• Publication Number:
  US 20040001164A1
• Time in Patent Office: 1,541 Days
• Field of Search: 382/100, 358/3.28, 713/176
• US Class Current: 382/100
• CPC Class Codes: H04N 1/32203 Spatial or amplitude domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/32208 involving changing the magnitude of selected pixels, e.g. overlay of information or super-imposition H04N1/32219, H04N1/32224 take precedence
• CPC Class Codes: H04N 1/32229 with selective or adaptive application of the additional information, e.g. in selected regions of the image H04N1/32213 takes precedence
• CPC Class Codes: H04N 1/32251 in multilevel data, e.g. greyscale or continuous tone data
• CPC Class Codes: H04N 1/32347 Reversible embedding, i.e. lossless, invertible, erasable, removable or distorsion-free embedding
• CPC Class Codes: H04N 2201/3269 of machine readable codes or marks, e.g. bar codes or glyphs
• CPC Class Codes: H04N 5/21 Circuitry for suppressing or minimising disturbance, e.g. moiré or halo

Abstract

This invention can multiplex noise on multilevel image data to reversibly embed visible additional information with a noise-multiplexed distribution while maintaining the atmosphere of the multilevel image data subjected to embedding. For this purpose, in this invention, when noise is multiplexed on multilevel image data to embed visible additional information with a noise-multiplexed distribution, information representing whether or not to multiplex noise for each pixel is input as the additional information. Whether a pixel of interest in the multilevel image data is located at a position where noise is to be multiplexed is determined on the basis of the additional information (S106). When the pixel of interest is determined to be located at the position where noise is to be multiplexed, the second bit region where noise is to be multiplexed is specified on the basis of the first bit region in a bit configuration which constitutes the pixel of interest (S110). Bit information in the second bit region of the specified pixel of interest is changed (S112, S114).

Claims

1. An image processing apparatus which converts multilevel image data into frequency component data for each pixel block of a predetermined size to compression-code the multilevel image data, and multiplexes noise on the multilevel image to embed visible additional information with a noise-multiplexed distribution, comprising:

input means for inputting, as the additional information, information representing whether or not to multiplex noise for each pixel block of the predetermined size;

determination means for determining on the basis of the input additional information whether a pixel block of interest is located at a position where noise is to be multiplexed;

specifying means for, when said determination means determines that the pixel block of interest is located at the position where noise is to be multiplexed, specifying a second bit region where noise is to be multiplexed, on the basis of a state of a first bit region in data which constitutes a low frequency component after conversion of the pixel block of interest; and

change means for reversibly changing bit information for the second bit region in the data of the low frequency component specified by said specifying means.

2. The apparatus according to claim 1, wherein the conversion into the frequency component includes orthogonal transform, and the low frequency component includes a DC component after orthogonal transform.

3. The apparatus according to claim 1, wherein the conversion into the frequency component includes wavelet transform, and the low frequency component includes data of a block of a low frequency component that is generated by wavelet transform a plurality of number of times.

4. The apparatus according to claim 1, wherein, in a case where the multilevel image data includes multilevel image data using a luminance value as a reference, the first bit region includes a predetermined number of upper bits including a most significant bit, and the second bit region includes lower m bits which include a least significant bit and change in accordance with a value of the second bit region.

5. The apparatus according to claim 1, wherein

the image processing apparatus further comprises means for setting information on an intensity for multiplexing noise, and

said specifying means specifies the second bit region on the basis of the set intensity information and the state of the first bit region.

6. An image processing apparatus which removes visible additional information from multilevel image data that is compression-coded by reversibly embedding noise, multiplexing the visible additional information, and converting the data into frequency component data for each pixel block of a predetermined size, comprising:

input means for inputting, as the additional information, information representing whether or not to multiplex noise for each pixel block of the predetermined size;

determination means for determining on the basis of the input additional information whether a pixel block of interest is located at a position where noise is multiplexed;

specifying means for, when said determination means determines that the pixel block of interest is located at the position where noise is multiplexed, specifying a noise-multiplexed second bit region on the basis of a first bit region in data which constitutes a low frequency component after frequency conversion of the pixel block of interest; and

reconstruction means for performing conversion inverse to noise multiplexing to reconstruct a state of the second bit region of the pixel block of interest specified by said specifying means into a state before multiplexing.

7. An image processing method of converting multilevel image data into frequency component data for each pixel block of a predetermined size to compression-code the multilevel image data, and multiplexing noise on the multilevel image to embed visible additional information with a noise-multiplexed distribution, comprising:

an input step of inputting, as the additional information, information representing whether or not to multiplex noise for each pixel block of the predetermined size;

a determination step of determining on the basis of the input additional information whether a pixel block of interest is located at a position where noise is to be multiplexed;

a specifying step of, when the pixel block of interest is determined in the determination step to be located at the position where noise is to be multiplexed, specifying a second bit region where noise is to be multiplexed, on the basis of a state of a first bit region in data which constitutes a low frequency component after conversion of the pixel block of interest; and

a change step of reversibly changing bit information bit information for the second bit region in the data of the low frequency component specified in the specifying step.

8. An image processing method of removing visible additional information from multilevel data that is compression-coded by reversibly embedding noise, multiplexing the visible additional information, and converting the data into frequency component data for each pixel block of a predetermined size, comprising:

an input step of inputting, as the additional information, information representing whether or not to multiplex noise for each pixel block of the predetermined size;

a determination step of determining on the basis of the input additional information whether a pixel block of interest is located at a position where noise is multiplexed;

a specifying step of, when the pixel block of interest is determined in the determination step to be located at the position where noise is multiplexed, specifying a noise-multiplexed second bit region on the basis of a state of a first bit region in data which constitutes a low frequency component after frequency conversion of the pixel block of interest; and

a reconstruction step of perfonning conversion inverse to noise multiplexing to reconstruct a state of the second bit region of the pixel block of interest specified in the specifying step into state before multiplexing.

9. A computer program, embodied in a computer-readable medium, for causing an apparatus to function as an image processing apparatus which converts multilevel image data into frequency component data for each pixel block of a predetermined size to compression-code the multilevel image data, and multiplexes noise on the multilevel image to embed visible additional information with a noise-multiplexed distribution, wherein said program causes the apparatus to function as:

input means for inputting, as the additional information, information representing whether or not to multiplex noise for each pixel block of the predetermined size;

determination means for determining on the basis of the input additional information whether a pixel block of interest is located at a position where noise is to be multiplexed;

specifying means for, when said determination means determines that the pixel block of interest is located at the position where noise is to be multiplexed, specifying a second bit region where noise is to be multiplexed, on the basis of a state of a first bit region in data which constitutes a low frequency component after conversion of the pixel block of interest; and

change means reversibly changing bit information for the second bit region in the data of the low frequency component specified by said specifying means.

10. A computer-readable storage medium storing a computer program defined in claim 9.

11. A computer program, embodied in a computer-readable medium, for causing an apparatus to function as an image processing apparatus which removes visible additional information from multilevel image data that is compression-coded by reversibly embedding noise, multiplexing the visible additional information, and converting the data into frequency component data for each pixel block of a predetermined size, functioning as:

input means for inputting, as the additional information, information representing whether or not to multiplex noise for each pixel block of the predetermined size;

determination means for determining on the basis of the input additional information whether a pixel block of interest is located at a position where noise is multiplexed;

specifying means for, when said determination means determines that the pixel block of interest is located at the position where noise is multiplexed, specifying a noise-multiplexed second bit region on the basis of a state of a first bit region in data which constitutes a low frequency component after frequency conversion of the pixel block of interest; and

reconstruction means for performing conversion inverse to noise multiplexing to reconstruct a state of the second bit region of the pixel block of interest specified by said specifying means into a state before multiplexing.

12. A computer-readable storage medium storing a computer program defined in claim 11.