Data embedding apparatus, data extracting apparatus, and method therefor, and recording medium having such methods recorded thereon

• US 6,850,624 B1
• Filed: 03/02/2000
• Issued: 02/01/2005
• Est. Priority Date: 11/29/1999
• Status: Expired due to Fees

• Current Assignee: National Institute of Information and Communications Technology
• Original Assignee: Hitachi, Ltd.
• Inventors: Miura, Nobuharu, Miyamoto, Yoh, Shinoda, Takashi
• Primary Examiner(s): Mehta, Bhavesh M.
• Assistant Examiner(s): AZARIAN, SEYED H
• Application Number:
  US09/517,514
• Time in Patent Office: 1,797 Days
• Field of Search: 382/100, 382/235, 382/248, 382/276, 382/167, 382/166, 382/240, 382/162, 382/232, 382/165, 382/168, 382/233, 382/274, 422/109, 422/110, 358/1.15, 358/1.9, 358/3.28, 345/788, 345/427, 380/200, 380/201, 380/243, 380/269, 348/254, 348/393.1, 348/717
• US Class Current: 382/100
• CPC Class Codes: G06T 1/0021 Image watermarking
• 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: H04N 1/32309 in colour image data
• CPC Class Codes: H04N 1/32347 Reversible embedding, i.e. lossless, invertible, erasable, removable or distorsion-free embedding

Abstract

An intended image data structure is assumed to have a color information storing region and a pixel information storing region as its components. First, consider that the color information storing region within the image data structure is divided into a plurality of subregions, and a corresponding bit value is defined for each of the subregions. Next, an index number stored for each of pixels within the pixel information storing region is changed to an index number belonging to a subregion corresponding to a bit value of information to be embedded. In this way, one bit or more of information can be embedded for each pixel. Thus, a large amount of information can be embedded into a small-size image composed of simple shapes and having a small number of colors without degrading the image quality, and the information can be extracted from the image in which it has been embedded.

Claims

1. A data embedding apparatus for embedding data into image data, having a color information storing region for storing information of colors used in an image in association with respective index numbers corresponding thereto, and a pixel information storing region for storing one of said index numbers in association with each pixel of the image, said data embedding apparatus comprising:

means for dividing said color information storing region into a plurality of subregions in which color values and the order in which the color values are stored are identical for each subregion, and for editing the color values and color value order in said color information storing region such that the respective subregions maintain mutually identical color values and color value order;

means for defining a bit value corresponding to each of said subregions; and

means for selecting a color existing in said pixel information storing region corresponding to one of the bit values as embedded data, for each pixel stored in said pixel information storing region.

2. A data embedding apparatus for embedding data into image data, having a color information storing region for storing information of colors used in an image in association with respective index numbers corresponding thereto, and a pixel information storing region for storing one of said index numbers in association with each pixel of the image, said data embedding apparatus comprising:

means for dividing said color information storing region into a plurality of subregions in which color values and the order in which the color values are stored are identical for each subregion, and for editing the color values and color value order in said color information storing region such that the respective subregions maintain mutually identical color values and color value order;

means for defining a bit value corresponding to each of said subregions; and

means for setting an index number corresponding to one of the bit values as embedded data, for each pixel stored in said pixel information storing region.

3. A data embedding method for embedding data into image data, in a data embedding apparatus having a color information storing region for storing information of colors used in an image in association with respective index numbers corresponding thereto, and a pixel information storing region for storing one of said index numbers in association with each pixel of the image, said data embedding method comprising the steps of:

dividing said color information storing region into a plurality of subregions in which color values and the order in which the color values are stored are identical for each subregion, and editing the color values and color value order in said color information storing region such that the respective subregions maintain mutually identical color values and color value order;

defining a bit value corresponding to each of said subregions; and

selecting a color existing in said pixel information storing region corresponding to one of the bit values as embedded data, for each pixel stored in said pixel information storing region.

4. A data embedding method for embedding data into image data, in a data embedding apparatus having a color information storing region for storing information of colors used in an image in association with respective index numbers corresponding thereto, and a pixel information storing region for storing one of said index numbers in association with each pixel of the image, said data embedding method comprising the steps of:

dividing said color information storing region into a plurality of subregions in which color values and the order in which the color values are stored are identical for each subregion, and editing the color values and color value order in said color information storing region such that the respective subregions maintain mutually identical color values and color value order;

defining a bit value corresponding to each of said subregions; and

setting an index number corresponding to one of the bit values as embedded data, for each pixel stored in said pixel information storing region.

6. A recording medium having recorded thereon an image embedded with data by the data embedding method according to claim 4.

5. A computer readable recording medium having recorded thereon a program for embedding data into image data, for use in a data reading apparatus having a color information storing region for storing information of colors used in an image in association with respective index numbers corresponding thereto, and a pixel information storing region for storing one of said index numbers in association with each pixel of the image, said program causing an information processing apparatus to execute the steps of:

editing said color information storing region;

of defining a bit value corresponding to each of subregions of said color information storing region; and

selecting a color existing in said pixel information storing region corresponding to one of the bit values as embedded data, for each pixel stored in said pixel information storing region.

7. A data embedding/extracting system, comprising:

a data embedding apparatus for embedding data into image data, having a color information storing region for storing information of colors used in an image in association with respective index numbers corresponding thereto, and a pixel information storing region for storing one of said index numbers in association with each pixel of the image, said data embedding apparatus comprising;

means for dividing said color information storing region into a plurality of subregions in which color values and the order in which the color values are stored are identical for each subregion, and for editing the color values and color value order in said color information storing region such that the respective subregions maintain mutually identical color values and color value order;

means for defining a bit value corresponding to each of said subregions; and

means for selecting a color existing in said pixel information storing region corresponding to one of the bit values as embedded data, for each pixel stored in said pixel information storing region; and

a data extracting apparatus including;

means for determining in which of the plurality of subregions of the color information storing region, a color specified by each pixel of the image exists;

means for extracting the bit value corresponding to the subregion thus determined for said each pixel; and

means for combining a set of the extracted bit values as data.

8. A data embedding/extracting system, comprising:

a data embedding apparatus for embedding data into image data, having a color information storing region for storing information of colors used in an image in association with respective index numbers corresponding thereto, and a pixel information storing region for storing one of said index numbers in association with each pixel of the image, said data embedding apparatus comprising;

means for dividing said color information storing region into a plurality of subregions in which color values and the order in which the color values are stored are identical for each subregion, and for editing the color values and color value order in said color information storing region such that the respective subregions maintain mutually identical color values and color value order;

means for defining a bit value corresponding to each of said subregions; and

means for selecting a color existing in said pixel information storing region corresponding to one of the bit values as embedded data, for each pixel stored in said pixel information storing region; and

a data extracting apparatus including;

means for determining the index number associated with each pixel of the image;

means for extracting the bit value corresponding to the index number thus determined for said each pixel; and

means for combining a set of the extracted bit values as data.

9. A data embedding/extracting method, comprising the steps of:

embedding data into image data, in a data embedding apparatus having a color information storing region for storing information of colors used in an image in association with respective index numbers corresponding thereto, and a pixel information storing region for storing one of said index numbers in association with each pixel of the image, including;

dividing said color information storing region into a plurality of subregions in which color values and the order in which the color values are stored are identical for each subregion, and editing the color values and color value order in said color information storing region such that the respective subregions maintain mutually identical color values and color value order;

defining a bit value corresponding to each of said subregions; and

selecting a color existing in said pixel information storing region corresponding to one of the bit values as embedded data, for each pixel stored in said pixel information storing region; and

extracting the data from the image data, including;

determining in which of the plurality of subregions of the color information storing region, a color specified by each pixel of the image exists;

extracting the bit value corresponding to the subregion thus determined for said each pixel; and

combining a set of the extracted bit values as data.

10. A data embedding/extracting method, comprising the steps of:

embedding data into image data, in a data embedding apparatus having a color information storing region for storing information of colors used in an image in association with respective index numbers corresponding thereto, and a pixel information storing region for storing one of said index numbers in association with each pixel of the image, including;

dividing said color information storing region into a plurality of subregions in which color values and the order in which the color values are stored are identical for each subregion, and editing the color values and color value order in said color information storing region such that the respective subregions maintain mutually identical color values and color value order;

defining a bit value corresponding to each of said subregions; and

selecting a color existing in said pixel information storing region corresponding to one of the bit values as embedded data, for each pixel stored in said pixel information storing region; and

extracting the data from the image data, including;

determining an index number associated with each pixel of the image;

extracting the bit value corresponding to the index number thus determined for said each pixel; and

combining a set of the extracted bit values as data.

11. A computer readable recording medium having recorded thereon a program for embedding data into image data and a program for decoding data embedded in the image data by a data embedding method, for use in an information processing apparatus having a color information storing region for storing information of colors used in an image in association with respective index numbers corresponding thereto, and a pixel information storing region for storing one of said index numbers in association with each pixel of the image,

said program for embedding data into image data causing the information processing apparatus to execute the steps of:

editing said color information storing region;

defining a bit value corresponding to each of subregions of said color information storing region; and

selecting a color existing in said pixel information storing region corresponding to one of the bit values as embedded data, for each pixel stored in said pixel information storing region; and

said program for decoding data in image data causing the information processing apparatus to execute the steps of;

determining in which of the subregions each pixel within an image body region exists;

extracting the bit value corresponding to the subregion thus determined for said each pixel; and

combining a set of the extracted bit values as said data.