JP4231927B2 - Image processing apparatus, image processing method, and program - Google Patents

Description

  The present invention relates to an image processing apparatus, an image processing method, and a program, and more particularly to a technique for embedding digital watermark information in an image.

  In recent years, digital contents such as images and music, which have been rapidly spreading, can be copied indefinitely without deteriorating the quality, so that problems such as illegal copying have arisen. As one of the countermeasures, there is a method of embedding special information in the digital content in a form that the user cannot easily recognize as it is, in other words, without damaging the quality of the digital content. This technique is called a digital watermark, and is one method for preventing or suppressing illegal copying. For example, copyright information relating to digital content can be protected by embedding copyright information as watermark information in the digital content. it can.

JP 2002-354227 A

  An object of the present invention is to provide an image processing apparatus, an image processing method, and a program capable of embedding watermark information in digital content so that it is difficult for an observer to see.

  The image processing apparatus of the present invention divides a two-dimensional bar code into three for wavelet transform means for performing wavelet transform on an original image and dividing the band into frequency components, and for high-frequency components obtained by the wavelet transform. A watermark information embedding means for dispersing and embedding the two-dimensional barcode in RGB components of the original image, and among the frequency components obtained by the wavelet transform, a high-frequency component in which the two-dimensional barcode is embedded Reconstructing means for reconstructing an image by replacing it with a component.

  The image processing method of the present invention performs wavelet transform on an original image to divide the band into frequency components, and divides a two-dimensional barcode into three for the high-frequency component obtained by the wavelet transform, thereby obtaining the two-dimensional The barcode is dispersed and embedded in the RGB components of the original image, and among the frequency components obtained by the wavelet transform, the high-frequency component is replaced with the high-frequency component in which the two-dimensional barcode is embedded, and the image is regenerated. It is characterized by comprising.

  The program according to the present invention includes a wavelet transform unit that performs wavelet transform on an original image and divides a band into frequency components, and a high-frequency component obtained by the wavelet transform by dividing a two-dimensional barcode into three. The watermark information embedding means for dispersing and embedding the dimensional barcode into the RGB components of the original image, and among the frequency components obtained by the wavelet transform, the high frequency component is converted into the high frequency component in which the two-dimensional barcode is embedded. The computer is made to function as a reconstruction means for reconstructing an image by replacing.

  According to the present invention, the original image is subjected to wavelet transform and divided into each frequency component, and the two-dimensional barcode as the watermark information is embedded only in the high frequency component so that the original data is not affected. Disappear. Therefore, it is possible to embed watermark information in the original image so that it is difficult for the observer to see.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram illustrating a configuration example of an image processing apparatus 10 according to an embodiment of the present invention. The image processing apparatus 10 shown in FIG. 1 is for embedding watermark information, that is, for embedding a two-dimensional barcode as watermark information in an original image.

  As shown in FIG. 1, the image processing apparatus 10 includes an image input unit 11, a wavelet transform unit 12, a watermark information input unit 13, a watermark information embedding unit 14, an image reconstruction unit 15, and an image output unit 16.

  The image input unit 11 is for inputting an original image which is an embedded image of watermark information. The original image input from the image input unit 11 is supplied to the wavelet transform unit 12. The wavelet transform unit 12 performs wavelet transform, which is one of frequency analysis, on the supplied original image. By this wavelet transform, the original image is decomposed (band division) into frequency components.

  The watermark information input unit 13 is for inputting watermark information to be embedded in the original image. In the present embodiment, the watermark information is a two-dimensional barcode (for example, a so-called QR code), and the watermark information input from the watermark information input unit 13 is supplied to the watermark information embedding unit 14.

  The watermark information embedding unit 14 embeds watermark information supplied from the watermark information input unit 13 only in specific frequency components among the frequency components obtained by applying wavelet transform to the original image in the wavelet transform unit 12. Here, the specific frequency component in which the watermark information is embedded is a frequency component that does not affect the quality of the original data. In this way, by embedding watermark information only in a specific frequency component obtained by performing wavelet transform on the original image, the calculation takes time compared to the case of directly embedding the watermark information in the sample value. There is an advantage that the embedded watermark information is hard to disappear.

  The image reconstruction unit 15 performs inverse transform (inverse wavelet transform) using each frequency component output from the wavelet transform unit 12 and the watermark information embedding unit 14 to reconstruct an image. Specifically, the image reconstruction unit 15 includes a specific frequency component in which the watermark information output from the watermark information embedding unit 14 is embedded, and each frequency output from the wavelet transform unit 12 excluding this specific frequency component. An inverse wavelet transform is performed with the components to reconstruct the image.

  In other words, the image reconstruction unit 15 reconstructs an image by replacing a specific frequency component among the frequency components output from the wavelet transform unit 12 with the watermark information embedded by the watermark information embedding unit 14. Thereby, an image in which watermark information is embedded in the original image is obtained.

  The image output unit 16 is for outputting an image with watermark information reconstructed by embedding watermark information in the original image as described above.

  Next, the operation of the image processing apparatus 10 shown in FIG. 1 will be described with reference to FIG. FIG. 2 is a diagram schematically showing a procedure for embedding watermark information (two-dimensional barcode) by the image processing apparatus 10.

  An original image 21 that is an embedded image of watermark information and a two-dimensional barcode 23 as watermark information are input from the image input unit 11 and the watermark information input unit 13, respectively. The original image 21 input from the image input unit 11 is subjected to wavelet transform by the wavelet transform unit 12 and is decomposed into frequency components 22.

  Specifically, as shown in FIG. 2, the original image 21 is decomposed into frequency components of LL22A, LH22B, HL22C, and HH22D by wavelet transformation. Here, LL22A is a multiresolution approximation (MRA component), and LH22B, HL22C, and HH22D are multiresolution representations (MRR components). The MRA component represents a low frequency component, whereas the MRR component represents a high frequency component, mainly an edge or noise component of the original image. Therefore, even if the MRR component changes slightly, it is difficult for the observer's eyes to determine the degree of deterioration due to it.

  Next, the watermark information embedding unit 14 embeds a two-dimensional barcode 23 with respect to the high-frequency component of each frequency component obtained by wavelet transforming the original image 21. Specifically, the difference information of each frequency component is used, and the two-dimensional barcode 23 that is watermark information is embedded in the MRR component that is a high frequency component. Here, as described above, the MRR component, which is a high-frequency component, is difficult to determine the degree of deterioration even if the MRR component is slightly changed. Therefore, reconfiguration is performed by embedding the two-dimensional barcode 23 in the high-frequency component using its properties. Thus, the deterioration of the image obtained can be made inconspicuous.

When embedding the two-dimensional barcode 23 in the high-frequency component obtained by wavelet transforming the original image 21, the embedding two-dimensional barcode 23 is divided into three parts and dispersed into the RGB components of the original image. It may be embedded. In this way, the embedding strength can be suppressed and the embedded information can be made inconspicuous.
Then, the image reconstruction unit 15 uses the MRA component and the MRR component in which the watermark information is embedded to reconstruct the image 24 with watermark information.

Next, an image processing apparatus for extracting a two-dimensional barcode from an image in which a two-dimensional barcode as watermark information is embedded as described above will be described.
FIG. 3 is a block diagram illustrating a configuration example of the image processing apparatus 30 on the side from which watermark information is extracted according to the present embodiment.

  As shown in FIG. 3, the image processing apparatus 30 includes an image capturing unit 31, a wavelet transform unit 32, an original image estimation unit 33, a watermark information extraction unit 34, and a watermark information output unit 37.

  The image capturing unit 31 captures an image in which watermark information is embedded (an image with watermark information). The image capturing unit 31 may be, for example, an image reading device such as a scanner or a multi-function device, or may be an imaging device such as a camera (including a device provided in a mobile terminal such as a mobile phone). The image captured by the image capturing unit 31 is supplied to the wavelet transform unit 32 and the original image estimation unit 33.

  The wavelet transform unit 32 performs wavelet transform on the image supplied from the image capture unit 31 and decomposes (band-divides) it into frequency components.

  The original image estimation unit 33 performs filtering on the image supplied from the image capture unit 31 to estimate an original image, that is, an image in which watermark information is not embedded. Specifically, the original image estimation unit 33 estimates the original image by performing filter processing using a noise removal filter on the supplied image. Also, the original image estimation unit 33 performs wavelet transform on the obtained estimated original image and decomposes (band-divides) it into frequency components.

  The watermark information extraction unit 34 includes a frequency component comparison unit 35 and a watermark information acquisition unit 36. The watermark information extraction unit 34 compares each frequency component output from the wavelet transform unit 32 with each frequency component output from the original image estimation unit 33, and extracts watermark information based on the comparison result.

  Specifically, in the watermark information extraction unit 34, the frequency component comparison unit 35 relates to each frequency component related to the image in which the watermark information from the wavelet transform unit 32 is embedded and the estimated original image from the original image estimation unit 33. Each frequency component is compared, and the difference information is supplied to the watermark information acquisition unit 36. The watermark information acquisition unit 36 extracts watermark information based on the supplied difference information.

  The watermark information output unit 37 is for outputting the watermark information extracted by the watermark information extraction unit 34.

  Next, the operation of the image processing apparatus 30 shown in FIG. 3 will be described with reference to FIG. 4 as appropriate. FIG. 4 is a diagram schematically showing a procedure for extracting watermark information (two-dimensional barcode) by the image processing apparatus 30.

  When the watermark information-containing image 41, which is an image in which watermark information is embedded, is captured by the image capturing unit 31, the watermark information-containing image 41 is subjected to wavelet transform by the wavelet transform unit 32 and decomposed into frequency components 42. Is done. Specifically, as shown in FIG. 4, the image 41 with watermark information is decomposed into frequency components of LL42A, LH42B, HL42C, and HH42D. The frequency components LL, LH, HL, and HH are the same as those shown in FIG.

  The watermark information-containing image 41 captured by the image capturing unit 31 is supplied to the original image estimation unit 33, and the original image 43 is estimated by performing a predetermined process. Further, the estimated original image 43 is subjected to wavelet transform and decomposed into frequency components 44. Specifically, as shown in FIG. 4, the estimated original image 43 is decomposed into frequency components of LL′44A, LH′44B, HL′44C, and HH′44D. Each frequency component LL ′, LH ′, HL ′, and HH ′ corresponds to LL, LH, HL, and HH, respectively.

  Next, the watermark information extraction unit 34 compares each frequency component 42 based on the watermark information-containing image 41 from the wavelet transform unit 32 with each frequency component 44 based on the estimated original image 43 from the original image estimation unit 33. To do. As a result, the two-dimensional barcode 45, which is watermark information embedded in the image 41, is extracted and output from the watermark information output unit 37. Then, by decoding the output two-dimensional barcode 45, information recorded by the two-dimensional barcode 45 can be obtained as shown in FIG.

  In the above description, in order to extract the watermark information, the original image is estimated from the image including the watermark information captured by the original image estimation unit 33. However, information on the original image itself (in detail, When each frequency component of the original image itself is obtained, an original image information input unit 33A may be provided as shown in FIG. 4 to input each frequency component of the original image.

As described above, according to the present embodiment, the original image input from the image input unit 11 is subjected to wavelet transform by the wavelet transform unit 12 to be decomposed into frequency components. After embedding a two-dimensional barcode in only the high-frequency component among the obtained frequency components by the watermark information embedding unit 14, the image reconstruction unit 15 reconstructs the image. In this way, by embedding the two-dimensional barcode as watermark information in the high-frequency component, the watermark information can be made inconspicuous and the watermark information can be embedded in the original image so that it is difficult for human eyes to see. When extracting a two-dimensional barcode from an image with watermark information embedded with a two-dimensional barcode as watermark information, by comparing each frequency component of the image with watermark information and the original image estimated therefrom, A two-dimensional barcode can be easily extracted.
Also, by using a two-dimensional barcode as watermark information, it becomes possible to embed a lot of information (character information) easily.

  In the above description, the image processing apparatus 10 that embeds watermark information and the image processing apparatus 30 that extracts watermark information have been described separately. However, both the function of embedding watermark information and the function of extracting watermark information are combined into one function. The image processing apparatus may be provided.

Here, as a usage form of the watermark information embedding method in the image according to the present embodiment described above, the following forms are conceivable.
Products via networks such as the Internet by embedding links to digital data in analog media with 2D barcodes that are watermark information, in other words, embedding 2D barcodes as shortcuts to information on the network Acquisition of information and simplification of ordering procedures can be realized. In order to refer to a link to digital data, an image in which the digital data is embedded may be taken using a camera, or an image may be captured using a scanner or a multifunction device.

As a specific example,
-In general, advertisements are strongly limited in space, and if a two-dimensional barcode is posted for each product, the number of products that can be placed is reduced, or the two-dimensional barcode alone makes it inconvenient. Therefore, by embedding a two-dimensional barcode indicating the provider of additional information related to each product image in the advertisement as watermark information, the product image and the two-dimensional barcode are separated as in the past, that is, two-dimensional. It is possible to allow the user to access additional information such as the latest product information without printing the barcode alone. In particular, in advertisements that sell a large number of products such as used car sales and rental properties, it is possible to easily access the latest information and purchase products by embedding a two-dimensional barcode for each product.
-In catalog gifts, etc., by embedding information for executing ordering processing with a two-dimensional barcode as watermark information in a product image, it is only necessary to shoot the target image (if a scanner or the like is used, the target is It is possible to place an order by simply marking it with a circle and reading it.

(Other embodiments of the present invention)
The image processing apparatus according to the present embodiment described above can be configured by a computer CPU or MPU, RAM, ROM, and the like, and can be realized by operating a program stored in the RAM or ROM. Therefore, the program that causes the computer to perform the above functions can be realized by recording the program on a recording medium such as a CD-ROM and causing the computer to read the program. As a recording medium for recording the program, a flexible disk, a hard disk, a magnetic tape, a magneto-optical disk, a nonvolatile memory card, or the like can be used in addition to the CD-ROM.

  In addition, the functions of the above-described embodiments are realized by executing a program supplied by a computer, and the program is used in cooperation with an OS (operating system) or other application software running on the computer. When the functions of the above-described embodiment are realized, or when all or part of the processing of the supplied program is performed by a function expansion board or a function expansion unit of the computer, the function of the above-described embodiment is realized. Such a program is included in the embodiment of the present invention.

  In order to use the present invention in a network environment, all or a part of the program may be executed on another computer. For example, the screen input process may be performed by a remote terminal computer, and various determinations, log recording, and the like may be performed by another center computer.

  For example, the image processing apparatus shown in this embodiment has a computer function 500 as shown in FIG. 5, and the CPU 501 performs the operation in this embodiment.

  As shown in FIG. 5, the computer function 500 includes a CPU 501, a ROM 502, a RAM 503, a keyboard controller (KBC) 505 of a keyboard (KB) 509, and a CRT controller (CRT) 510 of a CRT display (CRT) 510 as a display unit. A configuration in which a CRTC) 506, a hard disk (HD) 511, a disk controller (DKC) 507 of a flexible disk (FD) 512, and a network interface card (NIC) 508 are connected to each other via a system bus 504. It is said.

  The CPU 501 comprehensively controls each component connected to the system bus 504 by executing software stored in the ROM 502 or the HD 511 or software supplied from the FD 512.

  That is, the CPU 501 reads out and executes a processing program for performing the above-described operation from the ROM 502, the HD 511, or the FD 512, thereby performing control for realizing the operation in the present embodiment.

  The RAM 503 functions as a main memory or work area for the CPU 501. The KBC 505 controls an instruction input from the KB 509 or a pointing device (not shown). The CRTC 506 controls the display on the CRT 510.

  The DKC 507 controls access to the HD 511 and the FD 512 that store a boot program, various applications, user files, a network management program, a processing program in the present embodiment, and the like. The NIC 508 bidirectionally exchanges data with other devices on the network 513.

  The above-described embodiments are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereto. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

It is a block diagram which shows the structural example of the image processing apparatus (information embedding side) by this embodiment. It is a figure which shows typically the embedding procedure of the watermark information by the image processing apparatus shown in FIG. It is a block diagram which shows the structural example of the image processing apparatus (information extraction side) by this embodiment. It is a figure which shows typically the extraction procedure of the watermark information by the image processing apparatus shown in FIG. It is a block diagram which shows the computer function which can implement | achieve the image processing apparatus in this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Image input part 12 Wavelet transformation part 13 Watermark information input part 14 Watermark information embedding part 15 Image reconstruction part 16 Image output part 31 Image capture part 32 Wavelet transformation part 33 Original image estimation part 33A Original image information input part 34 Watermark information Extraction unit 35 Frequency component comparison unit 36 Watermark information acquisition unit 37 Watermark information output unit

Claims (3)

Wavelet transform means for performing wavelet transform on the original image and band-dividing each frequency component;
Watermark information embedding means for dividing a two-dimensional barcode into three parts and dispersing and embedding the two-dimensional barcode into RGB components of the original image with respect to the high-frequency component obtained by the wavelet transform;
An image processing apparatus comprising: reconstructing means for reconstructing an image by replacing a high-frequency component among the frequency components obtained by the wavelet transform with a high-frequency component in which the two-dimensional barcode is embedded. . Apply wavelet transform to the original image to divide the band into frequency components,
For the high-frequency component obtained by the wavelet transform, the two-dimensional barcode is divided into three, and the two-dimensional barcode is dispersed and embedded in the RGB components of the original image,
An image processing method, wherein an image is reconstructed by replacing a high-frequency component among the frequency components obtained by the wavelet transform with a high-frequency component in which the two-dimensional barcode is embedded. Wavelet transform means for performing wavelet transform on the original image and band-dividing each frequency component;
Watermark information embedding means for dividing a two-dimensional barcode into three parts and dispersing and embedding the two-dimensional barcode into RGB components of the original image with respect to the high-frequency component obtained by the wavelet transform;
A program for causing a computer to function as reconstruction means for reconstructing an image by replacing a high-frequency component among the frequency components obtained by the wavelet transform with a high-frequency component in which the two-dimensional barcode is embedded.

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