JP2019091976A - Program, image processing apparatus, and image processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique capable of embedding data at an appropriate position in an image. SOLUTION: An analysis is performed based on the pixel values of the pixels included in an image according to a predetermined analysis method corresponding to a predetermined embedding method for giving a predetermined change to the pixel values of the pixels included in the image. Then, in the image, the analysis in the image so that the data is embedded so that the first region capable of giving a predetermined change has priority over the second region in which the predetermined change cannot be given. Data is embedded in the position based on the result of the above according to a predetermined embedding method. [Selection diagram] FIG. 12

Description

  The present invention relates to a program for embedding data in an image, an image processing apparatus, and an image processing method.

  A technique called digital watermarking technology is used which multiplexes additional information so that it is difficult to visually distinguish the printed material. Hereinafter, steganography, watermarks, etc., superimposing data having another meaning on data, or the technical field thereof is generally referred to as “multiplexing”.

  Patent Document 1 describes multiplexing of audio information and the like on an image.

Japanese Patent Application Publication No. 2003-174556

  As a method of data multiplexing and decoding of the data, an apparatus that changes the image according to the data embedded in the image and captures a printed matter on which the image is printed generates the above variation based on the captured image. There is a way to decode the above data by capturing

  However, in the image in which the data is embedded, there are an area in which the data is likely to be changed (hereinafter also referred to as a specialty area) and an area in which the data is less likely to be changed (hereinafter referred to as a weak area). For example, it is assumed that each pixel value is a value in the range of 0 to 255, and 10 pixel values are added for multiplexing. In this case, it is possible to add 10 when the pixel value is less than 246, but when 10 is added when the pixel value is 246 or more, the range of 0 to 255 is exceeded. Can not. Even if the data is multiplexed to such a difficult area where it is difficult to make a change appropriately, the case where the data can not be found or the case where the data is misjudged may occur at the time of decoding.

  An object of the present invention is to provide a technique capable of embedding data at an appropriate position in an image.

  A program according to the present invention is a program for embedding data in an image according to a predetermined embedding method for giving a predetermined change to pixel values of pixels included in the image, and the predetermined corresponding to the predetermined embedding method Analysis means for performing analysis based on pixel values of pixels included in the image according to the analysis method of the above, and a first area capable of giving the predetermined change in the image gives the predetermined change Embedding means for embedding the data according to the predetermined embedding method at a position based on the analysis result by the analysis means so that the data is embedded prior to the second area which is not possible Make it work.

  According to the present invention, data multiplexing can be performed at an appropriate position in an image so that decoding of data multiplexed into the image can be performed more reliably.

It is a block diagram showing composition of an image processing system. FIG. 5 is a diagram showing a mask used for multiplexing processing. It is a figure for demonstrating the mask used for a multiplexing process. FIG. 6 is a diagram showing an image on which data is multiplexed. It is a figure which shows an example of the image by which data were multiplexed. It is a figure which shows the other example of the image by which data were multiplexed. It is a figure which shows an example of the result of having applied FFT to the image by which data were multiplexed. It is a figure which shows an example of the result of having applied FFT to the image to which data are not multiplexed. It is a figure which shows another example of the result of having applied FFT to the image by which data were multiplexed. It is a figure which shows another example of the result of having applied FFT to the image by which data were multiplexed. It is a figure which shows the pattern for determining the start position of embedded data. It is a flowchart which shows the determination process of the embedding position of the data in this embodiment. It is a figure showing an example of data composition of data embedded in a picture. It is a figure which shows the relationship between the information embedded as a file format part, and the kind of file format. It is a figure which shows an example of the result in which determination of the weak area was performed. It is a figure which shows an example of the image by which multiplexing was performed to the position determined by the process of this embodiment. It is a figure which shows an example of the result of embedding data being divided | segmented and embedded in a non-continuous block. It is a figure which shows an example of a data structure of embedded data. It is a figure which shows an example of the periodic pattern of the area | region where embedding data were embedded. It is a figure which shows another example of the result in which the determination of the weak area was performed. It is a figure which shows the example of the square area | region where all become an excellent area. It is a figure which shows another example of a data structure of embedded data.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The image processing apparatus in the embodiment includes a multiplexing apparatus for embedding additional information, and a separation apparatus for reading the additional information from the printed matter. As a multiplexing apparatus, printer driver software in a computer for creating image information to be output to a printer engine or built-in as application software. However, the present invention is not limited thereto, and may be incorporated as hardware and software in a copying machine, a facsimile, a printer main body, and the like. As a separation device, a camera-equipped mobile phone, a camera-equipped smartphone, a tablet PC, etc. may be mentioned. Hereinafter, such an imaging device is referred to as a camera-equipped mobile terminal. Alternatively, it may be a series of devices for separating additional information with an application program in a computer, with an image taken by a digital still camera.

First Embodiment
FIG. 1 is a block diagram showing the configuration of an image processing system according to the first embodiment.

  Reference numeral 102 denotes a multiplexing device, which is a device for embedding additional information in image information so as to make visual identification difficult. The multiplexing device 102 is included in a camera-equipped mobile terminal 201 such as a smartphone, for example. Reference numerals 100 and 101 both indicate an input unit provided in the camera-equipped mobile terminal 201. From 100, multi-gradation image information is input, and from 101, necessary additional information to be embedded in the image information is input. The additional information is information different from the image information input by the input unit 100. For example, audio information, moving image information, text document information, and identification information for identifying such information. Alternatively, various information such as a copyright, an imaging date and time, an imaging location, a photographer, and the like regarding an image input by the input unit 100, or other image information may be used.

  Reference numeral 103 denotes a printer, which outputs information generated by the multiplexing device using a printer engine. The printer 103 is, for example, an ink jet printer, a laser printer, or the like, which realizes gradation expression by using pseudo gradation processing.

  The camera-equipped mobile terminal 201 includes an imaging sensor 104, and the imaging sensor 104 captures an image of a printed matter printed by the printer 103. Then, the captured image obtained by the imaging is input to the separation device 105 included in the camera-equipped mobile terminal 201. Then, the separation device 105 analyzes the captured image to separate (extract) the additional information embedded in the printed matter, and outputs the additional information to the output unit 106. The output unit 106 is an interface that outputs the acquired additional information. For example, when the additional information is audio information, the additional information is output to the speaker 210 included in the mobile terminal with camera 201, and the audio is output. When the additional information is image information, the additional information is output to the display 211 of the mobile terminal with camera 201 and displayed. The output unit 106 may also output data to an external device. In addition, when there are a plurality of imaging sensors in the camera-equipped mobile terminal 201, the printed matter may be imaged by one or a plurality of imaging sensors.

  Note that the camera-equipped mobile terminal as the multiplexing device 102 and the camera-equipped mobile terminal as the separation device 105 may be the same terminal or different terminals.

  FIG. 1B is a hardware configuration diagram of the camera-equipped mobile terminal 201. The camera-equipped mobile terminal 201 includes, as an example, an interface 202, a CPU 203, a ROM 204, an operation unit 205, a RAM 206, an external storage device 207, a communication unit 208, and an imaging unit 209. Furthermore, the camera-equipped mobile terminal 201 has a speaker 210 and a display 211. These blocks are connected to one another using, for example, an internal bus.

  A CPU 203 is a system control unit and controls the entire apparatus. Like the RAM 206, for example, the RAM 206 is configured of a DRAM (Dynamic RAM) or the like that requires a backup power supply. The RAM 206 is also used as a main memory and a work memory of the CPU 203. The ROM 204 stores fixed data such as a control program executed by the CPU 203, a data table, and an OS program. For example, the ROM 204 stores an application downloaded from a server that provides various application programs (hereinafter referred to as an application) on the Web. The CPU 203 executes the program stored in the ROM 204 in the RAM 206 to operate as the multiplexing device 102 and the separating device 105 described above. The CPU 203 also operates as the input units 100 and 101 and the output unit 106 described above. For example, the CPU 203 inputs image information stored in the external storage device 207 from the external storage device 207 as the input unit 100. Further, the CPU 203 inputs additional information from the external storage device 207 or the RAM 206 as the input unit 101. Further, the CPU 203 causes the output unit 106 to output additional information as audio information to the speaker 210 to perform audio output, and outputs additional information as image information to the display 211 for display. When the additional information is identification information of voice information or image information stored in the external storage device 207, the CPU 203 reads voice information or image information from the external storage device 207 according to the identification information, and the speaker 210 or the display 211 Output to

  The communication unit 208 can communicate with an external device by communication such as a wireless LAN or a wired LAN. The speaker 210 outputs an audio. For example, when the camera-equipped mobile terminal 201 is a smartphone, the speaker 210 outputs voice from the other party, voice data in a voice file such as music, various notification sounds, and the like. The display 211 displays the additional information described above, an image captured by the imaging unit 209, an image read from the external storage device 207, and various icons and menus. The operation unit 205 is used by the user to give an instruction to the camera-equipped mobile terminal 201, includes a button and the like, and may be provided integrally with the display 211 as a touch panel. The imaging unit 209 is a camera, and the imaging sensor 104 described above is included in the imaging unit 209.

  Although the camera-equipped mobile terminal 201 shown in FIG. 1B has been described as an apparatus that can function as both the multiplexing apparatus 102 and the demultiplexing apparatus 105, the present invention is not limited to this, and it may be operated as only one of them. Good. For example, an application for operating as the multiplexing device 102 and an application for operating as the separation device 105 may be separately prepared by a server on the Web. Then, only one of them may be downloaded to the camera-equipped mobile terminal 201. In this case, a mobile terminal different from the mobile terminal operating as the multiplexing device 102 operates as the separation device 105.

  Next, a method of multiplexing additional information on an image using a multiplexing device will be described. The multiplexing method described below is an example, and is not limited to this method. In the description herein, a method of multiplexing information “hello” on an image using the camera-equipped mobile terminal 201 will be described.

  First, an information processing apparatus such as a camera-equipped mobile terminal 201 handles binary data. Binary data is information of “0” or “1”, and information of “0” or “1” is continuously connected to indicate specific data. For example, for the character information, a code corresponding to each character is defined by binary data. Which character corresponds to which binary data is defined by what is called "character code". Taking "shift JIS", which is one of character codes, as an example, "h" corresponds to binary data "01101000". Similarly, “e” corresponds to binary data “01100101”, “l” corresponds to “01101100”, and “o” corresponds to “01101111”. That is, the character "hello" can be expressed as "01101000011001010110110001101100111111" in binary data. Conversely, if binary data "011010000110010101101101011000110111" can be acquired, it can be converted to the character "hello".

  That is, the CPU 203 as the multiplexing device 102 embeds data in the image so that the separation device 105 can determine "0" or "1" as multiplexing processing. The CPU 203 inputs the data “hello” to be multiplexed as the input unit 101, but the data to be actually embedded is “0110100001100101011011000110110111111”. Although these two show the same information, in order to distinguish them, "hello" is added information, and "01101000011001010110110001101100111111" converted for embedding is called embedded data.

  Next, a method of multiplexing embedded data on an image will be described. In this embodiment, embedding of data indicating “0” or “1” is described, but the multiplexing method is not limited to embedding of “0” or “1”, and data is uniquely identified on the encoding side and the decoding side. Other information may be used as long as it can be mapped to Further, the size of the image to be multiplexed is described as 640 px in height and 480 px in width.

  FIG. 2 shows a mask used for the multiplexing process. Here, the masks shown in FIGS. 2A and 2B to generate “0” and “1” are masks configured in 8 px × 8 px. By adding the contents of the mask to the image, it is possible to give a pattern having periodicity to the 8 px × 8 px area in the image. FIG. 3 is a diagram for explaining a mask used for the multiplexing process, and visually shows what pattern the image gives the image. The position of “30” in the mask of FIG. 2 is represented by black, the position of “0” is represented by gray, and the position of “−30” is represented by white, and an oblique line as shown in FIG. .

  Here, a pseudo code that alternately applies the mask of FIG. 2A and the mask of FIG. 2B to the entire image is shown below.

  In the present embodiment, for the sake of explanation, the image data in the third row is a gray image, and a process in which a change is applied to the pixel value by a mask will be described. However, it is preferable that the color component to which a change is applied by the mask is one that is difficult for a human to visually recognize. For example, in a color image having RGB components, if red is dominant in a region of 8 px × 8 px to be modified by a mask, modifications may be made to the red component. In addition, RGB may be converted into Lab components, and a change may be made to b components that are said to be difficult for human to visually recognize. Also, there are various possible color components that can be changed by the mask, such as using YUV and Lab's ab in combination. Further, the value of the 8 px × 8 px mask shown in FIG. 2 is set to be a value close to 0 when the internal coefficients are summed. In the case of printing by a normal printer, the 8 px × 8 px area in the printed matter is a very small size. Therefore, even if a change is made inside this area, if the mask is set so that the sum of the values to be changed is close to 0, it is difficult for a human to visually recognize the change. It is possible to perform multiplexing as hard as possible.

  Addition of mask values for adding a pattern is performed only once for a certain pixel, and values are not added redundantly. That is, processing is performed in units of 8 × 8 blocks, which is the size of the mask.

  FIG. 4 is a diagram showing an image on which data is multiplexed, and FIG. 5 is a diagram showing an example of an image on which data is multiplexed. The image shown in FIG. 5 is an image in which a pattern of oblique lines is added to the image shown in FIG. In the image of FIG. 5, information of “0” and “1” is alternately embedded. That is, since the patterns shown in FIGS. 3A and 3B are alternately inserted in 8 × 8 block units, the pattern shown in FIG. 5 is obtained. In FIG. 5, for convenience of explanation, the gray image is described as being easily visible, but multiplexing processing is performed in consideration of color components, patterns, sizes, and the like which are originally difficult to visually recognize.

  FIG. 6 is a diagram showing another example of an image in which data is multiplexed. Specifically, it shows an image in which “0110100001100101011011000110110101111” which is embedded data corresponding to “hello” is embedded. Since this embedded data is 40-bit information, it is sufficient to embed it in an area of 40 8 × 8 blocks (320 × 8 pixels). However, in the present embodiment, as shown in FIG. 6, embedded data corresponding to “hello” is repeatedly embedded. Thus, by repeatedly embedding the same data, resistance to disappearance of the pattern due to scratches or stains of the printed matter can be enhanced, and the search at the time of decoding of the embedded data by the separation device 105 can be facilitated. Can.

  Also, assuming that the size of the image to which data is multiplexed is 640 × 480 pixels, the total number of pixels is 307,200. Therefore, the number of pixels required to embed “hello” is 320 × 8, which corresponds to 2560 pixels. That is, in the above example, the “hello” embedding is repeated 120 times (307200/2560 = 120). Also, when the same embedded data is repeatedly embedded, specific information indicating the beginning of the data may be embedded at the beginning of the embedded data. Then, when the embedded data is decoded, the position where the embedded data “hellо” is embedded can be recognized by the specific information.

  As described above, according to the multiplexing method according to the present embodiment, an image in which data is multiplexed has a periodic pattern. In order to explain the periodicity in the multiplexed image, the results of applying FFT (Fast Fourier Transform) to the image will be shown below using FIGS. 7 to 10.

  FIG. 7 is a diagram showing an example of the result of applying the FFT to an image in which data is multiplexed. On the other hand, FIG. 8 is a diagram showing an example of the result of applying the FFT to an image in which data is not multiplexed. The results shown in FIG. 7 indicate that a spectrum (white point) appears at a specific position as compared with FIG. Note that FIG. 7 and FIGS. 9 and 10 described later show that there is an image fluctuation (change in pixel value) in the direction of a straight line connecting the spectrum of the image by FFT and the center of the image. Further, the spectrum outward from the center of the image is a higher frequency component (the appearing interval is shorter), and the whiter is, the spectrum is strong, and the feature is strongly appeared in the image.

  FIG. 9 and FIG. 10 are diagrams showing another example of the result of applying the FFT to the data multiplexed image. Specifically, FIG. 9 shows the result of applying FFT to an image in which only “0” is multiplexed, and FIG. 10 shows the result of applying FFT to an image in which only “1” is multiplexed. . As shown in FIGS. 9 and 10, depending on whether the data to be embedded is “0” or “1”, the appearance of the spectrum differs in the result to which the FFT is applied. In FIG. 9, it can be seen that spectra are scattered at an angle of 45 degrees from the upper left through the center to the lower right. That is, it indicates that a change (change in pixel value) occurs at a certain interval in the direction of 45 degrees diagonally from the upper left to the lower right in the image. When “0” is repeatedly multiplexed, a mask is created so that the pixel value fluctuates in a certain cycle when going from the upper left pixel to the lower right pixel (FIG. 2A). On the contrary, in the multiplexing of “0”, when advancing to 45 ° diagonally from the upper right to the lower left, fluctuation of the pixel value hardly occurs, and also in FIG.

  On the other hand, in FIG. 10, it can be seen that spectra are scattered at an angle of 45 degrees from the upper right through the center to the lower left. That is, it indicates that a change (change in pixel value) occurs at a certain interval when moving in the image from upper right to lower left 45 degrees. This is because, in the case where “1” is repeatedly multiplexed, a mask is created so that fluctuation of pixel values occurs in a certain cycle in the direction from the upper right pixel to the lower left pixel (FIG. 2 (b)).

  As shown in FIG. 9 and FIG. 10, when the pixel value is changed with a mask having periodical fluctuations as shown in FIGS. 3 (a) and 3 (b), it is possible to determine whether "0" or "1" later. It can be seen that However, when embedding information in which “0” and “1” are mixed here, as shown in FIG. 7, “0” or “1” is represented by which block from the result of FFT in the whole image It is not possible to determine if it is. Therefore, in the present embodiment, the CPU 203 performs the size of the FFT analysis in the same 8 × 8 size as the multiplexed block. Then, the CPU 203 determines which of “0” and “1” corresponds to each block. By this method, the CPU 203 can extract binary data in which “0” and “1” corresponding to a plurality of continuous blocks are continuous.

  The method of determining whether each block corresponds to "0" or "1" is not limited to FFT. For example, edge detection in the diagonal direction may be performed to determine which of the edge pattern corresponding to “0” and the edge pattern corresponding to “1” are closer. Besides, various determination methods can be applied, such as determining whether the block to be determined is more similar to the block corresponding to “0” or the block corresponding to “1” using block matching. .

  Further, in order to prevent an erroneous determination due to the influence of noise or the like, the CPU 203 performs the determination again if the information amount equal to or more than a predetermined threshold value can not be obtained. In addition, when a pattern by embedded data to be multiplexed is included in the original image, it is considered that the embedded data is determined by the pattern, and as a result, the original embedded data is not properly extracted. Therefore, the CPU 203 may use a pre-filter for removing a pattern similar to the pattern by the embedded data to be multiplexed in the original image, and then multiplex the embedded data.

  When it is determined by the device for decoding embedded data such as the separating device 105 that each block corresponds to “0” or “1”, it is specified from which position (block) in the image the embedded data starts. You need to In that case, for example, a “pattern for start position determination” different from the previously described “0” and “1” patterns is multiplexed, so that the start of embedded data can be determined.

  FIG. 11 is a diagram showing a pattern for determining the start position of embedded data. As shown in FIG. 3, while the patterns corresponding to “0” and “1” are diagonal patterns in the 8 × 8 pixel block, the pattern for determining the start position of the embedded data is , Horizontal pattern of blocks.

  When the camera-equipped mobile terminal 201 acquires an image by the imaging sensor and decodes the data, the printed matter may be imaged in various directions. Further, it is conceivable that the distance between the camera-equipped mobile terminal 201 and the printed matter at the time of imaging also varies, that is, the size of the region corresponding to the printed matter in the imaged image also varies. Therefore, even in the 8 × 8 pixel block at the time of printing, which indicates “0” or “1”, the size in the captured image may differ depending on the imaging environment, and data may not be decoded correctly.

  Therefore, the camera-equipped mobile terminal 201 (separating device 105) rotates, reduces, and enlarges the captured image a plurality of times with different rotation angles and different magnifications, and a state in which information of “0” and “1” appears most strongly It is conceivable to search for Also, as shown in FIGS. 3 and 11, the patterns of “0” and “1” and the pattern for determining the start position of the embedded data can be distinguished by the difference in the direction of periodicity. . However, depending on the angle of the camera-equipped mobile terminal 201 with respect to the printed matter at the time of imaging, it is conceivable that the two can not be distinguished. However, the number of blocks corresponding to “0” and “1” is overwhelmingly larger than the block corresponding to the pattern for determining the start position of embedded data. Therefore, even if the embedded image is extracted from the captured image rotated at the rotation angle at which the number of blocks determined as “0” and “1” is the largest when the captured image is rotated by different rotation angles, for example Good.

  As described above, although a plurality of captured images having different angles and sizes are generated, it is assumed that the captured images in the following description are captured in the correct direction and the correct distance. That is, the decoding process is performed even if the pre-processing such as rotation, enlargement, or reduction is not performed on the captured image acquired by the imaging sensor.

  Next, a method of determining an area to be multiplexed in an image in the present embodiment will be described. In the multiplexing method as described above, for example, “0” or “1” is expressed by giving periodicity to the pixel value by adding or subtracting 10 to the pixel value of the original image by the mask of FIG. . However, pixel values in an image are finite values, and information in the range of 0 to 255 is usually handled. Here, if the pixel value is 10 to 245, addition or subtraction of 10 to the pixel value can be correctly performed, but if it is any other pixel value, the information can not be correctly provided. For example, when performing subtraction of 10 on "0", the data is out of the 0-255 data range, so it is converted to, for example, "0". That is, a pixel value of "-10" can not be given. In addition, when it is intended to subtract 10 from the pixel values of 1 to 9, for example, when the pixel value "0" is given, although it is possible to slightly change the pixel value, the difference of "10" is assumed Can not make As a result, the patterns of “0” and “1” may not be sufficiently expressed, which may make it difficult to make a determination at the time of decoding or may not be able to make a correct determination.

  Thereafter, in the image to be multiplexed, for example, an area including many pixels with pixel values outside the range of 10 to 245 is considered as an area where embedded data may not be provided as expected, and is not good area (unfavorable area) And write. On the other hand, in an image to be multiplexed, for example, an area including many pixels with pixel values in the range of 10 to 245 is described as an area of high potential as an area where embedded data can not be provided as expected. Note that even a single pixel alone is described as a weak area and a good area, not a weak pixel and a good pixel.

  Note that, as described above, by repeatedly multiplexing the same embedded data to different areas of the same image, even if decoding fails in a specific part (for example, a bad area), it is possible to use other parts. There is a method of compensating for it. However, when it is not possible to recognize where in the image the weak region is in the decoding apparatus, data restoration can only be secured by increasing the number of repetitions of the above-mentioned multiplexing. However, even if the number of repetitions is increased, all of them may include weak areas, and although sufficient areas exist, they may not be able to be decoded.

  Another method is to change the pixel values in the image so that appropriate multiplexing can be performed on weak areas in the image. For example, there is also a method of securing addition or subtraction of 10 to the pixel value by converting the pixel value of the original image so as to be within 10 to 245 (reducing the number of gradations). However, since this method changes many data of the original image, it causes deterioration of the image quality.

  Therefore, in the present embodiment, when embedding the embedded data in the image as the multiplexing device 102, the camera-equipped mobile terminal 201 analyzes the image, and there is a high possibility that the embedded data can be appropriately decoded at the time of decoding. Automatically. FIG. 12 is a flowchart showing the process of determining the embedded position of data in the present embodiment. Note that the multiplexing technology is a technology that is established by two methods of embedding data and decoding data, and each will be described as encoding and decoding. Each step shown in FIG. 12 is executed by the camera-equipped mobile terminal 201 operating as the multiplexing device 102. Specifically, a program such as an application corresponding to the processing of each step shown in FIG. 12 is stored in the ROM 204. The process shown in FIG. 12 is realized by the CPU 203 reading the program into the RAM 206 and executing the program.

  In step S1201, the CPU 203 acquires an image to be multiplexed. For example, the CPU 203 displays the thumbnail image of the image stored in the external storage device 207 on the display 211 by the function of the OS stored in the ROM 204. Then, the CPU 203 reads an image corresponding to the thumbnail image designated by the user using the operation unit 205 into the RAM 206 as an image to be multiplexed. Also, an image to be multiplexed may be acquired from a server on a network using a URL managed by an application.

  In step S1202, the CPU 203 acquires data to be embedded in the image data of the image acquired in step S1201. For example, the CPU 203 displays a text input screen on the display 211, and acquires text input by the user using the operation unit 205 as embedded data. Note that, as described above, since the data to be actually embedded in the image is binary data represented by “0” “1”, the CPU 203 converts the acquired text into character code into binary data. In addition, since binary data differs depending on the character code, the CPU 203 converts the binary code according to the designation of the character code if the character code is specified. The device on the decoding side can decode the embedded information by extracting this binary data from the captured image of the printed matter and converting the binary data into text according to the character code.

  In the above example, the text is multiplexed into the image. However, the present invention is not limited to this, and audio information or image information may be multiplexed, or identification information of an audio file or an image file (file name , File path, URL etc.) may be multiplexed. When the identification information is multiplexed, the device on the decoding side can acquire the file according to the identification information, and can perform audio output and image display using the acquired file.

  However, when various files are multiplexed in this way, the device on the encoding side needs to recognize what file format the embedded data is. In the device on the decoding side, if the decodable file format is not limited to, for example, the "character string of shift JIS", and audio data and image data can also be decoded, the file type may not be determined only by binary data. . Therefore, the camera-equipped mobile terminal 201 operating as the multiplexing device 102 embeds information indicating which file format is the data to be embedded, together with binary data indicating the content of the data.

  FIG. 13 is a diagram showing a data configuration of data to be embedded in an image. As shown in FIG. 13, in addition to the real data part of, for example, 40 bits, the file format part of 4 bits indicating the format of the file is also multiplexed. Information to be embedded as a file format unit is associated with the type of file format. FIG. 14 is a diagram showing the relationship between information embedded as a file format unit and the type of file format. The problem of the above-described file format can be solved by referring to the table in which the file format and the number are associated as shown in FIG. 14 by both the encoding side and the decoding side. For example, when the function for encoding and the function for decoding are provided by the same application, a table shown in FIG. 14 is defined in the application and stored in the camera-equipped mobile terminal 201 when the application is installed. Also, if the application for encoding and the application for decoding are provided separately, the application is created such that the same table is defined in each application.

  In step S1203, the CPU 203 determines a weak area (inappropriate area) in an image to which data is to be embedded. Here, for the purpose of explanation, it is assumed that a periodic change is given by adding or subtracting 10 pixel values of pixels included in a grayscale image.

  Here, the details of the process in S1203 will be described. First, the CPU 203 detects pixel values of an image in which data is to be embedded for all pixels, and determines whether 10 addition and subtraction (pixel value change processing) are possible. Specifically, it is determined whether the pixel value of each pixel is between 10 and 245. FIG. 15 is a diagram illustrating an example of the result of the determination of the weak area. In FIG. 15, the pixels whose pixel values are between 10 and 245 (pixels for which the process of changing the pixel values can be performed) are expressed in white, and the other pixels are expressed in black. That is, the area shown in white in FIG. 15 is an area (good area) where data can be embedded as expected. On the other hand, an area expressed in black is an area (a poor area) in which data may not be embedded as expected. In the above example, although the determination is performed for each pixel, the determination may be performed for each area configured by a plurality of pixels. For example, analysis may be performed for each 8 × 8 block, and a good area or a weak area may be determined by the average pixel of the block. However, if 32 pixels out of a total of 64 pixels of 8 px x 8 px are "0" and 32 pixels are "255", the average value is 127.5, and it may be determined as a good area despite the weak area originally Absent. In preparation for such a case, it is desirable to calculate the variance within an 8 px × 8 px block and to determine that it is a good area only when the variance is low (no variation in pixels). As described above, the good area and the weak area are determined based on the analysis result obtained by analyzing the pixels, such as each pixel or each area. In the above example, the image is divided into a good area and a weak area, but a plurality of stages such as a good area, a weak area, and an intermediate area may be provided.

  Further, in the present embodiment, it is determined whether addition and subtraction of 10 can be made to the pixel value of the pixel, but various methods can be used as the determination method of the good region and the poor region. For example, colors that are not suitable for multiplexing processing in the application are held in a table in advance, and by comparing each pixel (or each block) of the image in which data is embedded with the above-mentioned table May be determined. In particular, when photo data such as JPEG or PNG is printed by a printer, conversion from RGB data to CMYK data often occurs. In this case, it is rare that the fluctuation periodically performed on the image remains as it is. Also, there may be a difference between image data having a value of 0 to 255 that can be handled on the camera-equipped mobile terminal 201 and characteristics (color space) of colors that can be handled by the printer. As a result, even if 10 is added to or subtracted from the pixel value of the image by the camera-equipped portable terminal 201, if it is a color space that can not be expressed by the printer, for example, the fluctuation on the printer side is reduced to 5 addition or subtraction. It is also possible that Therefore, in an application having a function for decoding, even if a table is defined that indicates the characteristics of the printer (for example, how much the periodic change for data embedding deviates due to the conversion of the image data format by the printer). Good. Then, when the camera-equipped mobile terminal 201 performs the decoding, the good area and the weak area may be determined by referring to the above-mentioned table. This table may be acquired by the camera-equipped mobile terminal 201 communicating with the printer. Furthermore, although the determination of the good area and the poor area is not based on the color, the good area and the poor area may be determined by analyzing the pattern or frequency component of a certain area in the image. You may judge by the combination of and frequency.

  Further, in the present embodiment, as shown in FIG. 2 and FIG. 3, diagonal periodicity of 2 px width is given to each 8 px × 8 px block in the image. In the case of this encoding method, when the same pattern is present in the image to be embedded, the possibility of erroneous determination is high. That is, depending on the encoding method, areas that are not good vary. In addition, the strength area and the weakness area also differ depending on the characteristics of the portable terminal (image sensor). For example, with a certain portable terminal, due to the low sensor performance and the intervention of unique image processing, it may not be possible to obtain an expected value in a certain color component. That is, processing suitable for determining the weak area and the poor area differs depending on the encoding method to be used and the conditions of the imaging sensor and the decoding device assumed. Therefore, it is desirable to make different the determination methods of the poor area and the poor area according to this condition.

  Next, in S1204 to S1208, the CPU 203 determines the embedding position of the embedded data in the image based on the determination result of the weak area in S1203, and embeds the data in the area. Specifically, data is embedded in an image such that an area capable of giving a predetermined change to a pixel value is prioritized over an area not capable of giving the predetermined change. In the above-described multiplexing method, since the 8 px × 8 px blocks of “hello” are arranged in a row of 40 bit patterns, an area of 320 px × 8 px is required. Here, W and H are defined as variables indicating the number of blocks necessary for embedding embedded data, and data is embedded by W horizontal blocks and H vertical blocks of 8 px × 8 px. When data is embedded in an area of 320 px × 8 px, W = 40 and H = 1. The CPU 203 searches for an area of 320 px × 8 px, which is all white pixels (good areas) in the image shown in FIG.

  Specifically, in step S1204, the CPU 203 starts searching for an embedded area. The pixel serving as the reference for starting the search is the upper left pixel of the image in the first search, and is incremented downward and to the right in the second and subsequent searches. In S1205, the CPU 203 analyzes the pixel values of the pixels included in the image shown in FIG. 15 to determine whether the embeddable area is detected. Specifically, in S1205, the CPU 203 identifies the size of the area for embedding the data in the image according to the information amount of the data to be embedded, and searches for the area that is the size and corresponds to the area of strength . For example, in the image shown in FIG. 15, the CPU 203 determines whether all the 320 px × 8 px area having the pixel serving as the reference of the search as the upper left start point is a white pixel (good area). If it is determined that the embeddable area has been detected, the CPU 203 embeds data in the area detected in S1205 by the above-described method in S1206. Then, in step S1207, the CPU 203 changes the area detected in step S1205 to a black pixel (weak area) in the image illustrated in FIG. This process is determined to be a white pixel (special area) again when the process of S1205 is performed next, and is to avoid overlapping and embedding of data. If data is embedded at S1206 or if an embeddable area is not detected at S1205, the process proceeds to S1208. In step S1208, the CPU 203 determines whether search processing of the embeddable area has been performed for all pixels. For example, it is determined whether all the pixels of the image have become the above-described reference pixels. If it is determined that the search for the embeddable area has been performed for all pixels, the process ends. On the other hand, when the search processing of the embeddable area is not performed for all the pixels, the processing returns to S1205. At this time, as described above, the pixel serving as the reference of the search is updated. In step S1209, the CPU 203 executes the application and sends a command to the OS to execute print control for sending the image in which the data is embedded in steps S1204 to S1208 to the printer 103 for printing.

  An example of a program code for performing the same processing as the above-described S1204 to S1208 is shown below.

  In the 14th to 20th lines, it is determined whether the 320 px × 8 px area of interest is a good area which is white at all pixels. If a black area (black pixel) is included, the flag of isDrawable is false, and on the 22nd line, the process moves to the next search position before multiplexing processing is performed. If all the areas are white, the embedding process is performed on the area of 320 px × 8 px in the 24th line. In the 26th to 30th lines, the area subjected to the embedding process updates drawableMap to false in order to treat it as a non-multiplexable area.

  FIG. 16 is a diagram showing an example of an image in which multiplexing has been performed at the position determined by the process of this embodiment. In FIG. 16, in the image of FIG. 15, multiplexing is applied to an area where all 320 px × 8 px are white.

  However, although in FIG. 16 the embedding can be executed avoiding the weak area, there are many unused white areas (good areas). Therefore, the shape of the area used for the embedded data is not limited to the one described above. FIG. 17 is a diagram showing another example of an image in which multiplexing is performed at the position determined by the process of the present embodiment. In FIG. 17, for the area of 8 px × 8 px horizontally and 5 vertically aligned in the area of 64 px × 40 px, “0” or “1” included in the binary data in the direction from upper left to lower right Is embedded in the block. By adopting a shape where blocks are concentrated as in the area of 64px x 40px, there is a high possibility that the entire embedded data will enter even if the camera is brought closer, and an image of the area necessary for decoding is acquired clearly You are more likely to be able to. In addition, as the blocks corresponding to the embedded data are concentrated, there is also an advantage that the influence of the shift due to the aberration of the camera lens and the influence of the error due to the tilt of the camera become smaller.

  As described above, various shapes can be adopted as the shape of the area in which the embedded data is embedded, and the shape used for the image to be multiplexed and printed is automatically determined from a plurality of candidates which are the shape. It may be done. For example, the CPU 203 adopts different shapes as the area in which the embedded data is embedded, and executes the processing of S1203 and S1204 in FIG. Then, the CPU 203 specifies a shape in which the number of embeddings (the number of areas to be embedded) is largest when the same embedded data is repeatedly embedded in the area of strength. The embedded data is then multiplexed using the identified shape to generate an image for printing.

  As described above, various patterns can be adopted as a pattern of arranging 40 by 8 px × 8 px. Here, if it is assumed that blocks of 8 px × 8 px are arranged in W vertical and H horizontal, it is sufficient that the number of blocks is 40 or more, and it is understood that equation (1) should be satisfied.

W × H ≧ 40 (1)
That is, in the combination of W and H, it is sufficient to select the combination which can be arranged in the best area.

  In addition, although the above-mentioned embedding has been described for embedding of binary data of "hello", in the present embodiment, also regarding an example of embedding the data start position and information of variables W and H for processing on the decoding side. explain.

  FIG. 18 is a diagram showing an example of a data format of embedded data. As shown in FIG. 18, the embedded data includes a start position determination pattern 1801, a header portion 1802, and an actual data portion 1803. In the header portion, there is a block having a pattern different from “0” and “1”, and in the decoding apparatus, the position of the header can be specified by this block. The 4-bit information corresponding to W is embedded at a position shifted (x1, y1) from the position of the header, and the 4-bit information corresponding to H is embedded at a position shifted (x2, y2), (x3, y3 The shifted position is determined as the actual data section start position. A periodic pattern when data is embedded according to such an agreement will be described later with reference to FIG. Such an arrangement is determined by the application when the encoding process and the decoding process are realized by the same application. Further, when the encoding process and the decoding process are realized by separate applications, a common definition is made between the two applications. The data configuration shown in FIG. 18 also includes the file format unit described in FIG.

  FIG. 19 is a diagram showing an example of a periodic pattern of a region in which embedded data is embedded. FIG. 19 shows an example where embedded data in the data format shown in FIG. 18 is embedded in 9 × 9 blocks (an area of 72 px × 72 px). The start position determination pattern 1901 corresponds to 1801 in FIG. 18, and is expressed by the pattern shown in FIG. The W information 1902, the H information 1903, and the file format information 1904 are 4-bit information included in the header portion 1802 of FIG. 18, and are expressed by four blocks arranged side by side. The actual data 1905 corresponds to 1803 in FIG. 18, and represents 40 bits of binary data by 40 blocks of 8 in width and 5 in length.

  The form of the header portion shown in FIG. 18 is not limited to this, and may be extended to have various information, and the arrangement position of the start position determination block is not limited to that in FIG. Good. Also, in order to increase the accuracy of position determination, a plurality of start position determination blocks may be provided, or a larger size start position determination block may be provided. Further, in FIG. 19, the shape of the area in which the embedded data is embedded is a square, but it may be a rectangle other than a square.

  According to the process in the above embodiment, data can be embedded in the image by changing the pixel value of the pixel included in the image. Further, by analyzing the pixel values of the pixels included in the image, it is determined whether the pixel (area) is appropriate for performing the change. Therefore, it is possible to multiplex embedded data while avoiding a weak area where multiplexing may not be appropriately performed on an image. Therefore, in an apparatus for decoding, it is possible to reduce the case where multiplexed data can not be decoded properly. Furthermore, multiplexing can be performed with image quality deterioration suppressed, as compared with the method of changing pixel values in an image, for example, so that appropriate multiplexing can be performed in a weak area in the image.

Second Embodiment
In the second embodiment, processing for embedding embedded data in non-consecutive blocks will be described. In the first embodiment, the embedded data is embedded in successive blocks in the image. However, there may be a case where there is no good area in the image corresponding to the number of consecutive blocks that can represent all the embedded data. In particular, when the amount of information of data to be embedded is large or when the information determined to be the good area is severe, the good area corresponding to the number of consecutive blocks in which all the information can be embedded does not exist in the image. There is. Also in such a case, processing for embedding information using only the good area is described. Hereinafter, “0” or “1” or an 8 px × 8 px block for representing the start position is described as a “basic block”, and a combination of basic blocks in a form used for decoding is referred to as a “data block”. That is, the blocks shown in FIGS. 3A and 3B and FIG. 9 are basic blocks, and the blocks shown in FIG. 19 are data blocks.

  In the first embodiment, multiplexing is performed by adding or subtracting 10 pixel values. In the second embodiment, multiplexing is performed by adding or subtracting 15 pixel values. FIG. 20 is a diagram showing another example of the result of determination of the weak region by the process of S1203 of FIG. 12 under such conditions. As in FIG. 15, the black part in the image is the poor area, and the white part in the image is the good area. Here, the content embedded in the image is not "hello" but "Congrats on your tenth birthday". The above characters are all 31 characters including spaces, and if one character is 8 bits, 248 bits of information is required in total. That is, when an 8 px × 8 px pattern as shown in FIGS. 3A and 3B is used to represent “0” or “1”, at least 248 basic blocks to represent the above character string Is required. Although the block (data block) in which data is embedded is described as a square for the purpose of explanation in the present embodiment, the block is not limited to a square, and may be a rectangle other than a square.

  First of all, the CPU 203 detects a square area, which is a good area in FIG. FIG. 21 is a diagram showing an example of a square area in which all are good areas. The block A is a 96 px × 96 px square area, and the block B is a 120 px × 120 px square area. The area of block A corresponds to 144 in the number of basic blocks, and the area of block B corresponds to 225 in the number of basic blocks. Both of these do not meet the 248 basic blocks required to express “Congrats on your birthday”, but if the two are combined, the 248 can be met. Therefore, in the second embodiment, “Congrats on your tenth birthday” is expressed using both the area of block A and the area of block B. Here, “Congrats on” (96 bits) is embedded in the block A, and “your tenth birthday” (152 bits) is embedded in the block B.

  In order to express one data by two blocks, in addition to the information of the embodiment, information indicating “from where in the entire data to where the data is” is required. In order to realize this, a header is created as shown in FIG. FIG. 22 is a diagram illustrating another example of the data configuration of embedded data. The start position determination pattern 2201 is the same as the above-described start position determination pattern, and thus the description thereof is omitted. The total data number 2202 indicates the total number of data of embedded data, and in this case, indicates 248 bits. The number of actual data 2203 is a value indicating how many bits of data are contained in the actual data part. For example, the actual data number 2203 in block A indicates 96, and the actual data number 2203 in block B indicates 152. The start offset 2204 indicates where in the entire embedded data the data included in the data block starts from. Since the data for the block A starts from the beginning, the start offset 2204 indicates "0", and for the block B, the start offset 2204 indicates "96" in the sense that information from the 96th bit onwards will be included.

  According to the data format shown in FIG. 22, the apparatus on the decoding side can recognize the combining method of the data extracted from the plurality of divided data blocks, and can decode the embedded data. Further, in the example of FIG. 22, the header portion in the data block needs 37 bits including the block at the start position, and 74 bits are necessary if it is two. Further, since the actual data part is 248 bits, the total of the header part and the actual data part is 322 bits, and 322 basic blocks are required. Since the block A includes 144 basic blocks and the block B includes 225 basic blocks, a total of 369 basic blocks are included. That is, in the data of the present embodiment, by using the block A and the block B together, it is possible to embed the above-mentioned 322-bit embedded data.

  Although “Congrats on your tenth birthday” is divided into “Congrats on” and “your tenth birthday” in the present embodiment, information may be duplicated. That is, if there is room for the data block, it may be embedded like "Congrats on your" and "on your tenth birthday".

  Although in the present embodiment, data is described by combining two data blocks, data may be expressed by two or more data blocks. However, in order to divide data blocks, a header portion for expressing them is necessary, and as the number of divisions increases, overhead of the header portion increases. Therefore, it is desirable that the number of divisions be as small as possible.

  Further, in the present embodiment, only two squares of the good area are described for the sake of explanation, but there may be a case where there are a plurality of squares of the good area. The following procedure can be considered as a method of determining the position and size of the block by the CPU 203 in that case. The following procedure also includes a method to embed data without splitting.

  In step 1, the CPU 203 determines the minimum data block size that can embed all data to be embedded. In step 2, the CPU 203 searches for a position satisfying the condition of the good area with the size determined in step 1. In step 3, the CPU 203 embeds information at the position searched in step 2. Then, the CPU 203 repeats the processes of steps 1 to 3 until the process of step 2 is performed on the entire area of the image. The above steps 1 to 3 are realized, for example, by the processing of S1204 to S1208 of FIG.

  In step 4, the CPU 203 searches for a position smaller than the size determined in step 1, which satisfies the condition of the specialty area. The process in step 4 is performed, for example, when the number of embeddings in step 3 is equal to or less than a predetermined number. In step 5, the CPU 203 adds the size of the good area every time the good area is searched in step 4. Then, in step 6, if the size added in step 4 is a size that can embed the header part and the actual data part in step 6, the CPU 203 divides and embeds embedded data in a plurality of good areas. Then, the CPU 203 repeats the processes of steps 4 to 6 until the process of step 4 is performed on the entire area of the image.

  That is, by the processing of steps 1 to 3, if there is a good area where data can be embedded without division, data is embedded in the good area. On the other hand, in the processes of steps 4 to 6, an area into which data can be divided and embedded is searched, and data is divided and embedded in the area. As described above, the conditions of the above-mentioned good area are set appropriately in accordance with the characteristics of encoding and decoding. By dividing and embedding the embedded data as described above, it becomes possible to embed data even if the continuous strength region is insufficient in size to embed all data.

(Other embodiments)
Although the data embedding in the above embodiment has been described as all rectangular, it may not be rectangular. For example, it is also possible to arrange the basic block in a circular area by putting x coordinate, y coordinate and radius information in the header part of the data block. Also, in the above embodiments, although it has been described that the weak area is not included in the data block, it is not necessary to remove all the weak areas from the data block. For example, the coordinates of the weak area in the data block may be described in the header portion of the data block, and the basic block may not be arranged at that position. For example, in the determination of the weak area and the strong area, it is possible to take measures such as “To allow the content ratio of the weak area in the attention area up to 10%”.

  Furthermore, in the above embodiment, as a method of determining the weak area with respect to the target pixel, it is determined whether data embedding is possible according to a predetermined embedding method. For example, if the predetermined embedding method is a method of giving a predetermined change (for example, addition or subtraction of 10) to the pixel value, the CPU 203 determines whether or not the change (addition or subtraction) can be performed. . Then, in the image, the data embedding position is determined such that the area in which the change is possible is embedded in the data with priority over the area in which the change is not possible. However, the present invention is not limited to this. For example, even if addition or subtraction of 10 is not possible, an allowable range may be provided such that if 8 or 9 of addition or subtraction is possible, it may be determined as a pixel corresponding to a good area. In this case, the change given to the pixel value as the data embedding method is "addition or subtraction of 8 to 10 to / from the pixel value", and the area in which the change is possible has priority over the area in which the change is not possible. Is embedded.

  In addition, when data is embedded in a batch so as not to be divided in a good area in an image, data may not be embedded in the weak area, or data may be collectively embedded in the weak area. Even in this case, it is possible to prevent data from being embedded in the area where the good area and the weak area are mixed. At the same time, for example, even when breakage or stains occur in a portion corresponding to the special region in the printed matter and decoding of the data becomes difficult, it is possible to leave room for decoding from the portion corresponding to the weak region.

  The function of the present embodiment can also be realized by the following configuration. That is, program code for performing the processing of this embodiment is supplied to a system or apparatus, and the computer (or CPU or MPU) of the system or apparatus executes the program code. In this case, the program code itself read out from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code also implements the functions of the present embodiment.

  Further, the program code for realizing the functions of the present embodiment may be executed by one computer (CPU, MPU), or may be executed by cooperation of a plurality of computers. It is also good. Furthermore, the program code may be executed by a computer, or hardware such as a circuit for realizing the function of the program code may be provided. Alternatively, part of the program code may be implemented by hardware, and the remaining part may be executed by a computer.

Claims (15)

A program for embedding data in an image according to a predetermined embedding method for giving a predetermined change to pixel values of pixels included in the image,
Analysis means for performing analysis based on pixel values of pixels included in the image according to a predetermined analysis method corresponding to the predetermined embedding method;
In the image, the first region capable of giving the predetermined change is embedded in the image such that the data is embedded in preference to the second region not capable of giving the predetermined change. Embedding means for embedding the data according to the predetermined embedding method at a position based on the analysis result by the analysis means;
A program to make a computer function.   The program according to claim 1, wherein the analysis means analyzes the result in the case where the predetermined change is given to the pixel value by the predetermined embedding method as the predetermined analysis method.   The program according to claim 2, wherein the analysis means analyzes, as the predetermined analysis method, whether or not the pixel value can be given the predetermined change.   The program according to any one of claims 1 to 3, wherein the embedding unit embeds the data at a position based on the analysis result and the information amount of the data.   The embedding means specifies the size of the area in the image for embedding the information amount of the data, searches for an area having the specified size and the analysis result by the analysis means satisfies a predetermined condition, 5. The program according to claim 4, wherein the data is embedded in an area detected by a search.   The program according to claim 5, wherein the predetermined condition is that all pixels in the area can execute the predetermined embedding method.   The program according to claim 5 or 6, wherein the embedding means divides and embeds the data into a plurality of non-consecutive areas of the image based on an amount of information of the data.   The embedding means has the non-continuous data satisfying the predetermined condition when the specified size and a region where the analysis result by the analysis means satisfies the predetermined condition is not detected by the search. The program according to claim 7, wherein the program is divided and embedded in a plurality of areas.   The image processing apparatus according to any one of claims 1 to 8, wherein the data is embedded so as to be difficult to visually distinguish by the embedding unit.   The program according to any one of claims 1 to 9, further causing the computer to function as a print control unit that causes a printer to print the image in which the data is embedded by the embedding unit.   11. The program according to claim 10, wherein the embedding unit embeds the data at a position according to the analysis result and the characteristic of the printer.   The image processing apparatus according to any one of claims 1 to 11, wherein the embedding unit repeatedly embeds the same data in different areas of the image.   13. The apparatus according to claim 1, wherein the embedding unit embeds the data in the image such that the data is embedded in the first area and the data is not embedded in the second area. The image processing apparatus according to any one of the above. An image processing apparatus for embedding data in an image according to a predetermined embedding method for giving a predetermined conversion to pixel values of pixels included in the image,
Analysis means for performing analysis based on pixel values of pixels included in the image according to a predetermined analysis method corresponding to the predetermined embedding method;
In the image, the first region capable of giving the predetermined change is embedded in the image such that the data is embedded in preference to the second region not capable of giving the predetermined change. Embedding means for embedding the data according to the predetermined embedding method at a position based on the analysis result by the analysis means;
An image processing apparatus comprising: An image processing method for embedding data in an image according to a predetermined embedding method for giving a predetermined change to pixel values of pixels included in the image,
An analysis step of performing analysis based on pixel values of pixels included in the image according to a predetermined analysis method corresponding to the predetermined embedding method;
In the image, the first region capable of giving the predetermined change is embedded in the image such that the data is embedded in preference to the second region not capable of giving the predetermined change. Embedding the data according to the predetermined embedding method at a position based on the analysis result in the analysis step;
An image processing method comprising: