JP2007174107A - Method, device and program for embedding digital watermark, and method, device and program for detecting digital watermark - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a digital watermark by using a device having low throughput, such as a portable telephone having a camera, from an image in which a plurality of pieces of given information are embedded as a watermark. <P>SOLUTION: When the digital watermark is embedded; at least one rectangle is arranged at even intervals so that it does not overlap, the inputted and given information to be embedded is converted to a digital watermark image, the digital watermark image is overlapped inside respective rectangles arranged at even intervals, a tiling digital watermark image is overlapped to the image, and the digital watermark image is outputted. When the digital watermark is detected; an image having the digital watermark composed of rectangular regions arranged at even intervals while the rectangular regions do not overlap is photographed by the camera, the rectangular region is detected from the captured image, and the digital watermark information is detected from the detected rectangular region. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electronic watermark embedding method and apparatus and program, and an electronic watermark detection method and apparatus and program, and more particularly, to a technique for embedding given information in content such as an image or video and detecting the given information. In a certain digital watermark embedding technique and detection technique, a digital watermark embedding method and apparatus for embedding a plurality of digital watermark information in one image and detecting the information, a program, and a digital watermark detection method and apparatus And the program.

The digital watermark technique used for copyright management is a technique for giving minute changes in pixel values to digital media information such as still images, embedding information, and detecting the information (for example, Non-Patent Document 1). Non-Patent Document 2). According to this technique, as shown in FIG. 12, a plurality of given information is not embedded in one image, and when a digital watermark of such an image is detected, it is not like a mobile phone with a camera. Naturally, it is not realized to detect a digital watermark in real time using an apparatus with a low processing capability.
Takao NAKAMURA, Hiroshi OGAWA, Atsuki TOMIOKA and Youichi TAKASHIMA, “Improved Digital Watermark Robustness against Translation and / or Cropping of an Image Area”, IEICE TRANS. FUNDAMENTALS, VOL., E83-A, NO.1, JANUARY 2000 Takao Nakamura, Atsushi Katayama, Masashi Yamamuro, Noboru Sone, “High-speed digital watermark detection method from analog images using a mobile phone with camera”, IEICE Transactions D-II Vol. J87-D-II No.12 pp.2145-2155 December 2004

  As described above, conventionally, a plurality of given information has not been embedded in one image, and the processing capability of a camera-equipped mobile phone is low when detecting a digital watermark of such an image. Of course, it is not realized to detect a digital watermark in real time using an apparatus.

  The present invention has been made in view of the above points, and uses an apparatus having a low processing capability such as a camera-equipped mobile phone from an image in which a plurality of given information that has not been realized as a conventional technique is embedded as a digital watermark. It is an object of the present invention to provide a digital watermark embedding method and apparatus and program, and a digital watermark detection method and apparatus and program for enabling detection of a digital watermark.

  FIG. 1 is a principle configuration diagram of the present invention.

The present invention (Claim 1) is a digital watermark embedding method for embedding information in an image,
The rectangular tiling means includes a rectangular tiling step (step 1) for arranging one or more rectangles at equal intervals so as not to overlap each other.
A digital watermark image generation step (step 2) in which the digital watermark image generation means converts the given given information to be embedded into a digital watermark image;
A digital watermark image tiling step (step 3) in which a digital watermark image tiling unit superimposes a digital watermark image inside each rectangle arranged at equal intervals in the rectangular tiling step;
The image superimposing means performs an image superimposing step (step 4) for superimposing the tiling digital watermark image obtained in the digital watermark image tiling step on the input image.

The present invention (Claim 2) is a digital watermark detection method for detecting digital watermark information embedded in an image,
An imaging step (step 11) in which the imaging means captures an image with a digital watermark composed of rectangular areas arranged at equal intervals so as not to overlap with each other;
A rectangular area detecting step (step 12) in which a rectangular area detecting unit detects a rectangular area from the captured image obtained in the imaging step (step 11);
The digital watermark detection means performs a digital watermark detection step (step 13) for detecting digital watermark information from the rectangular area detected in the rectangular area detection step (step 12).

Further, according to the present invention (Claim 3), in the rectangular area detection step (Step 12) of Claim 2,
Detecting a plurality of rectangles from the captured image obtained in the imaging step (step 11);
The given information determining means further performs a given information determining step of determining one given information by combining the digital watermark information for each of the plurality of rectangles obtained in the digital watermark detecting step.

The present invention (Claim 4) is a digital watermark detection method for detecting digital watermark information embedded in an image,
A code detection step in which the code detection means reads the input barcode or two-dimensional code;
An imaging step in which the imaging means captures an image composed of rectangular areas arranged at equal intervals so as not to overlap with the camera;
A rectangular area detecting means for detecting a rectangular area from a captured image obtained from the imaging step;
A digital watermark detection step in which digital watermark detection means detects digital watermark information from the rectangular area detected in the rectangular area detection step;
The given information determining means performs a given information determining step of determining one given information by combining the information obtained in the code detection step and the digital watermark information obtained in the digital watermark detection step.

  FIG. 2 is a principle configuration diagram of the present invention.

The present invention (Claim 5) is a digital watermark embedding device for embedding information in an image,
Rectangle tiling means 10 for arranging one or more rectangles at equal intervals so as not to overlap,
Digital watermark image generation means 20 for converting the given given information to be embedded into a digital watermark image;
A digital watermark image tiling means 30 for superimposing a digital watermark image inside each of the rectangles arranged at equal intervals in the rectangular tiling means 10;
Image superimposing means 40 for superimposing the tiling digital watermark image obtained by the digital watermark image tiling means 30 on the input image.

The present invention (Claim 6) is a digital watermark detection apparatus for detecting digital watermark information embedded in an image,
An imaging unit 110 that captures with a camera a digital watermarked image composed of rectangular areas arranged at equal intervals so as not to overlap;
A rectangular area detecting means 120 for detecting a rectangular area from a captured image obtained by the imaging means 110;
Digital watermark detection means 130 for detecting digital watermark information from the rectangular area detected by the rectangular area detection means 120.

Further, the present invention (Claim 7) is provided in the rectangular area detecting means 120.
Means for detecting a plurality of rectangles from the captured image obtained by the imaging means 110;
There is further provided given information determining means for determining one given information by combining the digital watermark information for each of the plurality of rectangles obtained by the digital watermark detecting means.

The present invention (Claim 8) is a digital watermark detection apparatus for detecting digital watermark information embedded in an image,
Code detection means for reading the input barcode or two-dimensional code;
An imaging means for capturing an image composed of rectangular regions arranged at equal intervals so as not to overlap with a camera;
A rectangular area detecting means for detecting a rectangular area from a captured image obtained from the imaging means;
Digital watermark detection means for detecting digital watermark information from the rectangular area detected by the rectangular area detection means;
A given information determining unit configured to determine one given information by combining the information obtained by the code detecting unit and the digital watermark information obtained in the digital watermark detecting step;

  The present invention (Claim 9) is a digital watermark embedding program that causes a computer to function as the digital watermark embedding apparatus according to claim 5.

  The present invention (Claim 10) is a digital watermark detection program for causing a computer to function as the digital watermark detection apparatus according to claims 6 to 8.

  As described above, in the present invention, by embedding different digital watermark information for each part, it can be associated with different network resources and provide a wide range of information from one image that was impossible with conventional digital watermark technology. It becomes possible.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First embodiment]
In the present embodiment, a digital watermark embedding apparatus and method will be described.

  FIG. 3 shows the configuration of the digital watermark embedding apparatus according to the first embodiment of the present invention.

  The digital watermark embedding apparatus shown in FIG. 1 includes a rectangular tiling unit 10, a digital watermark image generation unit 20, a digital watermark image tiling unit 30, and an image superimposing unit 40.

  The rectangular tiling unit 10 arranges the rectangular images at equal intervals so as not to overlap the embedded images.

  The digital watermark image generation unit 20 converts a plurality of given information to be embedded as an input digital watermark into a digital watermark image.

  The digital watermark image tiling unit 30 superimposes the digital watermark image inside each rectangle arranged at equal intervals in the rectangular tiling unit 10.

  The image superimposing unit 40 superimposes the tiling digital watermark image obtained by the digital watermark image tiling unit 30 on the input image and outputs the image as a digital watermarked image.

  FIG. 4 is a flowchart of the digital watermark embedding operation according to the first embodiment of the present invention.

  Step 101) An appropriate rectangular image is prepared in advance in a memory (not shown), and the rectangular tiling unit 10 reads the rectangular image from the memory (not shown) so that the rectangular images do not overlap. Arrange at equal intervals. As shown in FIG. 5, first, a rectangular image having an appropriate size is prepared. Since the rectangular images are arranged at equal intervals so as not to overlap in the subsequent processing, the rectangular images may be prepared with an appropriate size suitable for the processing. The rectangular images read from the memory (not shown) are arranged at equal intervals so that the rectangles do not overlap on the same pixel size as the image in which the digital watermark is embedded.

  Step 102) Next, the digital watermark image generation unit 20 converts the given information to be embedded inputted as the digital watermark information into a digital watermark image and stores it in a memory (not shown). Here, there are a plurality of given information. As shown in the given information A, B, and C in FIG. 6, when a plurality of pieces of given information are embedded as digital watermark information, a plurality of digital watermark images are input.

  Step 103) The digital watermark image tiling unit 30 acquires a digital watermark image stored in a memory (not shown), and embeds it in each rectangular image arranged in the rectangular tiling unit 10. For example, different digital watermark images may be embedded in all rectangles. That is, a method of embedding a digital watermark image by inputting given information with a serial number to a rectangular image is conceivable. Further, the digital watermark image may be embedded by performing image processing such as quantization including binarization and pseudo gradation processing such as a dither method.

  Step 104) The image superimposing unit 40 superimposes the image embedded with the input digital watermark and the image embedded with the digital watermark image on the rectangular image created by the digital watermark tiling unit 30, thereby converting the image with the digital watermark. create.

  The created digital watermarked image is output to a storage means such as a memory or a digital watermark detection apparatus described later.

  In this embodiment, an example is described in which a digital watermark is embedded in a still image. However, the present embodiment is not applied only to a still image, and may be a moving image.

  According to the present embodiment, by tiling a rectangular image and embedding digital watermark images having different given information inside the rectangular image, a plurality of digital watermark images are embedded in one image. It becomes possible.

  In addition, by performing image processing such as quantization, including binarization, and pseudo-gradation such as dithering, the digital watermark image becomes an effective digital watermark embedding method even when the image is printed. . In other words, copiers, facsimile machines, etc. often output multi-valued images with pseudo-gradation, and if digital watermark images are created with multi-tone representations and printed as they are, the digital watermark images will be destroyed. There is. In order to avoid such problems, it is possible to embed digital watermarks that are effective for printing by pre-quantizing digital watermark images including binarization or pseudo-gradation. Become.

[Second Embodiment]
In the present embodiment, a case will be described in which digital watermark information is detected from an image with a digital watermark embedded with a plurality of given information output in the first embodiment.

  FIG. 7 shows the configuration of a digital watermark detection apparatus according to the second embodiment of the present invention.

  The digital watermark detection apparatus shown in FIG. 1 includes a photographing unit 110, a rectangular area detection unit 120, a digital watermark detection unit 130, a given information determination unit 140, and a resource identification unit 150.

  The imaging unit 110 captures an image with a digital watermark input from the digital watermark embedding device shown in the first embodiment with a camera.

  The rectangular area detection unit 120 detects a rectangular area from the captured image provided from the imaging unit 110.

  The digital watermark detection unit 130 detects digital watermark information from the rectangular area detected by the rectangular area detection unit 120.

  The given information determination unit 140 determines one given information from a plurality of detected digital watermark information.

  The resource specifying unit 150 specifies a network resource associated with the determined given information.

  FIG. 8 is a diagram showing a digital watermark detection operation in the second embodiment of the present invention.

  Step 201) In the photographing unit 110, an image in which a plurality of digital watermark information is embedded (for example, an image with a digital watermark in the image superimposing unit 40 in FIG. 6) is photographed using a camera and stored in a memory (not shown). To do. The camera may be a camera digital camera, a camera-equipped mobile phone, a camera-equipped mobile terminal, or a camera-equipped personal computer.

  Step 202) The rectangular area detection unit 120 reads a captured image from a memory (not shown) of the photographing unit 110, and detects a rectangular area from the captured image. It is assumed that an existing method is used as the rectangular area detection method. For example, the rectangular area may be detected using a method described in Non-Patent Document 2 or a method such as edge detection. Further, if there is one rectangular area in the captured image, that area is detected, and if there are a plurality of areas, a plurality of areas are detected. Alternatively, the number of rectangles to be detected may be determined in advance, and the number of rectangular regions may be detected according to the image conditions. Specifically, a method of giving a constraint condition for detecting a rectangle located at the center of the image and detecting one rectangle at that position may be used.

  Step 203) The digital watermark detection unit 130 detects the digital watermark information embedded in the rectangular image detected in step 202. However, the image captured by the camera has a projection distortion or the like depending on the shooting position and the shooting angle. Even if the digital watermark is detected from the image as it is, the digital watermark cannot be detected. Therefore, image correction such as projection distortion is performed, and a digital watermark is detected from the corrected image (normalized image). This makes it possible to detect a digital watermark from an image distorted by the camera. Specifically, as shown in FIG. 9, projection distortion has occurred in an image taken by a camera. This is corrected by using projective transformation or the like on a normalized image having the same aspect ratio as the original image. The image corrected in this way is converted into a normalized image having the same aspect ratio as the original image. Since the normalized image is not distorted, it is possible to detect the digital watermark from this image and obtain the digital watermark information.

  When there are a plurality of detected rectangular images, the respective digital watermark information is detected. In detection, it goes without saying that digital watermark detection is performed after distortion correction is performed on each captured image as described above.

  The digital watermark information detected as described above is stored in a memory (not shown).

  Step 204) The given information determination unit 140 determines one given information from the detected digital watermark information in the memory (not shown). That is, as shown in FIG. 8D, when three pieces of digital watermark information A information, B information, and C information are detected, A, B, and C are integrated into one given information. To do. The given information integration method may be a simple combination of information, or may be converted by using a mapping table on a database to constitute one given information.

  Step 205) Finally, the resource specifying unit 150 stores a database (not shown) in which the given information and the network resource are stored in association with each other based on the given information determined by the given information determining unit 140. Are converted to network resources associated with the given information, for example, URL information, and associated with information on the network.

  In the above example, a still image is described, but a moving image is also included.

  According to the present embodiment, it is possible to detect digital watermark information embedded in a rectangular area at a location photographed by a camera from digital watermark information embedded in a plurality of images. For example, if only the head region is photographed from the digital watermarked image of the “dog” image shown in FIG. 6, it is possible to detect the digital watermark information of only the head as shown in FIG. 8B. Thereby, it becomes possible to make it correspond with the network specialized in the head part of the dog.

  In the conventional digital watermark technique, since only one piece of digital watermark information is embedded in one image, it has not been realized to associate with network resources in a form specialized for a part of the image. Further, when a plurality of rectangles are obtained in the partial area, it is possible to associate the information with network resources by integrating the information. In this way, embedding different information for each part of an image has a great effect as a digital watermark information providing method that has not been available so far.

  In this embodiment, digital watermark detection can be performed in real time even using a device with low processing capability such as a camera-equipped mobile phone. It is possible to specify a watermark embedding range by providing a rectangular area for embedding a digital watermark, simplify detection of the watermark, and easily perform camera distortion correction using projective transformation or the like. It is because it can do.

[Third Embodiment]
Furthermore, as shown in FIG. 10, a wider range of information can be provided by combining a barcode or a two-dimensional code.

  FIG. 11 shows the configuration of a digital watermark detection apparatus according to the third embodiment of the present invention. The configuration shown in the figure is a configuration in which a code detection unit 210 is added to the configuration in FIG.

  The same digital watermark information is embedded in the image composed of a plurality of pages by the method described above, and information on the corresponding page is coded by, for example, a two-dimensional code. When the digital watermark is detected, first, the code detection unit 210 reads the two-dimensional code information, and then the digital watermark detection unit 130 reads the digital watermark information. From the number of pages and the digital watermark information of each image, even the digital watermark information at the same rectangular position on each page can be associated with different network resources.

  As a result, it is possible to further increase the diversity of association of digital watermarks with network resources.

  The operations of the digital watermark embedding apparatus and the digital watermark detection apparatus according to the first and second embodiments described above can be constructed as a program, installed in a computer and executed, or distributed via a network. It becomes possible.

  Further, the constructed program can be stored in a portable storage medium such as a hard disk, a flexible disk, or a CD-ROM, and installed in a computer or distributed.

  The present invention is not limited to the above-described embodiment, and various modifications and applications can be made within the scope of the claims.

  The present invention can be applied to a technique for performing digital watermark detection in a device with low processing capability such as a camera-equipped mobile phone. Further, it can be applied not only to still images but also to moving images.

It is a figure for demonstrating the principle of this invention. It is a principle block diagram of this invention. It is a block diagram of the digital watermark embedding apparatus in the 1st Embodiment of this invention. It is a flowchart of the operation | movement of digital watermark embedding in the 1st Embodiment of this invention. It is a figure for demonstrating operation | movement of the rectangular tiling part in the 1st Embodiment of this invention. It is a figure which shows the detail of operation | movement of the image superimposition part from the digital watermark image generation part in the 1st Embodiment of this invention. It is a block diagram of the digital watermark detection apparatus in the 2nd Embodiment of this invention. It is a figure which shows the digital watermark detection operation | movement in the 2nd Embodiment of this invention. It is a figure which shows the example of normalization in the digital watermark detection part in the 2nd Embodiment of this invention. It is a figure which shows the example which performs the code detection in the 3rd Embodiment of this invention. It is a block diagram of the digital watermark detection apparatus in the 3rd Embodiment of this invention. It is a figure for demonstrating the prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Rectangle tiling means, Rectangle tiling part 20 Digital watermark image generation means, Digital watermark image generation part 30 Digital watermark image tiling means, Digital watermark image tiling part 40 Image superimposition means, Image superposition part 110 Imaging means, photographing part 120 rectangular area detection means, rectangular area detection section 130 digital watermark detection means, digital watermark detection section 140 given information determination section 150 resource identification section 210 code detection section

Claims (10)

An electronic watermark embedding method for embedding information in an image,
The rectangular tiling means includes a rectangular tiling step for arranging one or more rectangles at equal intervals so as not to overlap,
A digital watermark image generating means for converting the input given information to be embedded into a digital watermark image;
A digital watermark image tiling step, wherein the digital watermark image tiling means superimposes the digital watermark image inside each of the rectangles arranged at equal intervals in the rectangular tiling step;
An image superimposing means for superimposing the tiling digital watermark image obtained in the digital watermark image tiling step on the image;
An electronic watermark embedding method comprising: A watermark detection method for detecting watermark information embedded in an image, comprising:
An imaging step in which the imaging means captures an image with a digital watermark composed of rectangular areas arranged at equal intervals so as not to overlap with each other;
A rectangular area detecting means for detecting a rectangular area from the captured image obtained in the imaging step;
A digital watermark detection step in which digital watermark detection means detects digital watermark information from the rectangular area detected in the rectangular area detection step;
An electronic watermark detection method comprising: In the rectangular area detecting step,
Detecting a plurality of rectangles from the captured image obtained in the imaging step;
The given information determining means further performs a given information determining step of determining one given information by combining digital watermark information for each of the plurality of rectangles obtained in the digital watermark detecting step. The electronic watermark detection method described. A watermark detection method for detecting watermark information embedded in an image, comprising:
A code detection step in which the code detection means reads the input barcode or two-dimensional code;
An imaging step in which the imaging means captures an image composed of rectangular areas arranged at equal intervals so as not to overlap with the camera;
A rectangular area detecting means for detecting a rectangular area from a captured image obtained from the imaging step;
A digital watermark detection step in which digital watermark detection means detects digital watermark information from the rectangular area detected in the rectangular area detection step;
A given information determining step for determining one given information by combining the information obtained in the code detecting step and the digital watermark information obtained in the digital watermark detecting step;
An electronic watermark detection method comprising: An electronic watermark embedding device for embedding information in an image,
Rectangle tiling means for arranging one or more rectangles at equal intervals so as not to overlap;
Digital watermark image generation means for converting the given given information to be embedded into a digital watermark image;
Digital watermark image tiling means for superimposing the digital watermark image inside each of the rectangles arranged at equal intervals in the rectangular tiling means;
Image superimposing means for superimposing the tiling digital watermark image obtained by the digital watermark image tiling means on the image;
A digital watermark embedding apparatus comprising: An electronic watermark detection apparatus for detecting electronic watermark information embedded in an image,
An image pickup means for taking an image with a digital watermark composed of rectangular areas arranged at equal intervals so as not to overlap;
A rectangular area detecting means for detecting a rectangular area from a captured image obtained by the imaging means;
Digital watermark detection means for detecting digital watermark information from the rectangular area detected by the rectangular area detection means;
A digital watermark detection apparatus comprising: The rectangular area detecting means includes
Means for detecting a plurality of rectangles from the captured image obtained by the imaging means;
7. The digital watermark detection apparatus according to claim 6, further comprising given information determining means for determining one given information by combining a plurality of pieces of digital watermark information for each of the rectangles obtained by the digital watermark detecting means. An electronic watermark detection apparatus for detecting electronic watermark information embedded in an image,
Code detection means for reading the input barcode or two-dimensional code;
An imaging means for capturing an image composed of rectangular regions arranged at equal intervals so as not to overlap with a camera;
A rectangular area detecting means for detecting a rectangular area from a captured image obtained from the imaging means;
Digital watermark detection means for detecting digital watermark information from the rectangular area detected by the rectangular area detection means;
Given information determining means for determining one given information by combining the information obtained by the code detecting means and the digital watermark information obtained in the digital watermark detecting step;
A digital watermark detection apparatus comprising: Computer
6. A digital watermark embedding program that functions as the digital watermark embedding device according to claim 5. Computer
9. A digital watermark detection program that functions as the digital watermark detection apparatus according to claim 6.

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