JP4607771B2 - Image processing method, image processing apparatus, program executed by computer, and computer-readable recording medium - Google Patents

Description

  The present invention relates to an image processing method, an image processing apparatus, a program to be executed by a computer, and a computer-readable recording medium, and more particularly, an electronic watermark is embedded in digital content by encoding, and is embedded in digital content. The present invention relates to an image processing method, an image processing apparatus, a program executed by a computer, and a computer-readable recording medium that detect copyright information, falsification, and the like in the process of restoring the digital watermark.

Digital information can be easily copied by a computer or the like without being deteriorated, and conversely, digital information can be easily rewritten or altered. For this reason, digital information can be illegally copied and reused without permission by simple processing and operations, or can be partially altered so that it cannot be used for evidence photographs.

As a technique for preventing this, there are methods called digital watermarking and data hiding. Digital watermarking is a technique for adding invisible information when digital contents such as digital images are normally reproduced.
The method of embedding a digital watermark can be roughly classified into the following two.
(1) Method of embedding directly in sample value of content data (2) Method of embedding in frequency component

In the method (1), when processing such as processing or compression is performed, embedded data is easily lost, but the processing is light. On the other hand, the method (2) is strong in processing such as processing and compression, but has a characteristic that embedding and extraction are heavy.

The digital watermark that is stored in a data format that is difficult to express gradation, such as a color image that can only use a specific color or a binary image, which is a subject of the present invention, is difficult to apply the method (2). It is common to use a method. As will be described later, the present invention is realized by the method (1).

Applications for adding digital watermarks to digital content include recording copyright information, tracking illegal copy information, IP address history recording, preventing illegal copying (invisible and highly resistant type),
Application to tampering prevention (invisible / low tolerance), authentication, secret communication, embedding digital content annotations and labels (visible / irreversible type, owner's display), watermark removal enabled (visible / reversible type,
Content distribution).

Among them, for example, as a digital camera application, the camera serial number at the time of photography,
There has been proposed a method in which a camera is provided with a mechanism for embedding a date and time in a photographed image and simultaneously creating an electronic signature thereof (see Non-Patent Documents 1 and 2). As a result, in addition to detection of alteration of the ID photo, it is possible to identify the shooting camera and check the shooting date and time. Tampering detection is possible only with the digital signature technology, but by using the watermark technology, it is possible to specify the shooting camera and shooting date and time, and it works effectively by preventing tampering. Furthermore, by increasing the amount of information embedded in the digital watermark, the accuracy of specifying the falsification location is improved. In addition, if a lot of information can be watermark-embedded for copyright protection, it becomes easier to extract information when the embedded information is analyzed, and the effectiveness is enhanced.

However, by embedding a digital watermark,
Since data deteriorates, it is important to reduce image quality deterioration due to the influence even if the amount of embedded data is increased.

By the way, using the property that “the human eye is less capable of sensing noise present at the edge portion than the ability to sense noise present in the flat portion of the image”, the digital watermark is directly applied to the image. In the case of embedding, a watermark is generally embedded in the image edge portion. However, in the image area, usually, the edge part is narrower than the flat part, and the image quality deteriorates remarkably when the embedded watermark amount is large. In particular, deterioration of image quality that excessively erodes the contour lines of artificially created images such as forms, drawings, maps, or disrupts or erases the skeleton lines of images is the information and meaning of the original image. Will be lost.

In other words, watermark information embedding is desirable to increase the amount of watermark information to be embedded while minimizing image quality degradation in order to improve the performance of falsification detection and copyright information extraction. There is a trade-off relationship between the amount of watermark to be embedded and the image quality deterioration level in which the degree of deterioration increases.

  For example, in Non-Patent Document 3, the opening (representing digital watermark ON / bit signal) and closing (representing the same OFF / bit signal) of morphology (for example, refer to Non-Patent Document 4 for the morphology) are performed on the binary image. A technique is disclosed in which an original image is deteriorated by being applied to have durability, and an electronic watermark signal can be easily extracted.

  However, the technique of this document has a problem that image quality deterioration is easily noticeable because the intersections of the edge portions (sword tip portions and sharp cut portions) in the binary image change greatly (smooth).

Research report on digital watermarking technology, March 1999, edited by Japan Electronics Industry Promotion Association Nikkei Business, Prevention of Unauthorized Copying of Electronic Information, February 23, 1998 p. 68-70 (1998) Digital watermarking using morphological signal processing, IEICE Transactions A Vol. J84-A No. 8, p1037-1044, August 2001 issue, Akihiro Okamoto, by Akio Miyazaki Morphology, Hidefumi Obata, 1996, Corona

  The present invention has been made in view of the above problems, and is executed by an image processing method, an image processing apparatus, and a computer that can improve performance such as tampering detection and copyright information extraction while suppressing deterioration in image quality. An object of the present invention is to provide a program and a recording medium.

  In order to solve the above-described problems and achieve the object of the present invention, the present invention is directed to a solid region formed with the same color of an image, and the region boundary (edge) line is parallel to a horizontal or vertical direction line. In the first step of dividing each portion to be regarded as a rectangular boundary, a digital watermark is expressed by independently erasing or dilating in the object in each divided rectangular area. In accordance with the contents of the structural element of the calculation, the unit of the structural element for the measurement value that captures the increase or decrease of the movement amount of the boundary position of the object area formed with the same color as the erosion or dilation target in the divided image area A second step of using even-oddness of the value divided by the quantity as 1-bit information is included.

  Further, according to a preferred aspect of the present invention, in the second step, the object area formed with the same color as the target is regarded as a sector with respect to the degree of the erosion or dilation operation, and corresponds to the main point (Kaname). The point of intersection with the boundary (ridgeline) of the previous solid coating area that extends in a specific direction toward the ridgeline of the fan is maximized, and the degree of the erosion or dilation operation is reduced toward the both ends of the fan. It is desirable to do.

  Further, according to a preferred aspect of the present invention, in the second step, the object area formed with the same color as the target is regarded as a sector with respect to the degree of the erosion or dilation operation, and corresponds to the main point (Kaname). From the point to the point where the intersection with the border (ridgeline) part of the previous solid area that extends in the direction of 45 degrees close to the diagonal of the rectangle is maximized, the degree of the erosion or dilation operation is increased toward the both ends of the fan. It is desirable that the change is “0” at both ends of the fan.

  Also, according to a preferred aspect of the present invention, in the second step, the solid area formed in the same color is formed into a rectangle at a position where the area boundary (edge) line is parallel to a horizontal or vertical line. When two parallel parts are biased in either the horizontal or vertical direction in the division, it is desirable to determine that the inside of the rectangle is not the target of the digital watermark.

  Further, according to a preferred aspect of the present invention, in the second step, it is desirable to set the solid-filled area object as a digital watermark target object when there is no change even if the solid area object is opened or closed.

  Further, according to a preferred aspect of the present invention, in the second step, when the digital watermark target object is subjected to erection or dilation operations in the vicinity of 4 and 8 in the vertical direction and the horizontal direction separately in combination, It is desirable to do so by defining or transforming structural elements in morphology.

  According to a preferred aspect of the present invention, in the second step, the increasing or decreasing unit size representing the degree of the erosion or dilation operation constitutes a coefficient representing a magnification in a structural element in morphology. Therefore, it is desirable that the proportional change by the coefficient is possible.

  In order to solve the above-described problems and achieve the object of the present invention, the present invention is directed to a solid region formed with the same color of an image, and the region boundary (edge) line is parallel to a horizontal or vertical direction line. A first means for dividing each part to be regarded as a rectangular boundary part and an object in each divided rectangular area represent a digital watermark by independently erasing or dilating, and the digital watermark includes a morphology In accordance with the contents of the structural element of the calculation, the unit of the structural element for the measurement value that captures the increase or decrease of the movement amount of the boundary position of the object area formed with the same color as the erosion or dilation target in the divided image area And second means for using even-oddness of the value divided by the quantity as 1-bit information.

  Further, according to a preferred aspect of the present invention, the second means regards the object area formed with the same color as the target as a sector for the degree of the erosion or dilation operation, and corresponds to the main point (Kaname) The point of intersection with the boundary (ridgeline) of the previous solid coating area that extends in a specific direction toward the ridgeline of the fan is maximized, and the degree of the erosion or dilation operation is reduced toward the both ends of the fan. It is desirable to do.

  Further, according to a preferred aspect of the present invention, the second means regards the object area formed with the same color as the target as a sector for the degree of the erosion or dilation operation, and corresponds to the main point (Kaname) From the point to the point where the intersection with the border (ridgeline) part of the previous solid area that extends in the direction of 45 degrees close to the diagonal of the rectangle is maximized, the degree of the erosion or dilation operation is increased toward the both ends of the fan. It is desirable that the change is “0” at both ends of the fan.

  Also, according to a preferred aspect of the present invention, the second means forms the solid area formed in the same color into a rectangle at a position where the area boundary (edge) line is parallel to a horizontal or vertical line. When two parallel parts are biased in either the horizontal or vertical direction in the division, it is desirable to determine that the inside of the rectangle is not the target of the digital watermark.

  Further, according to a preferred aspect of the present invention, it is desirable that the second means is a digital watermark target object when there is no change even if the solid area object is opened or closed.

  According to a preferred aspect of the present invention, when the second means performs a combination of erection or dilation operations in the vicinity of 4 and 8 near the electronic watermark target object separately in the vertical direction and the horizontal direction, It is desirable to do so by defining or transforming structural elements in morphology.

  Further, according to a preferred aspect of the present invention, the second means is configured such that the increasing or decreasing unit size indicating the degree of the erosion or dilation operation constitutes a coefficient indicating a magnification in a structural element in morphology. Therefore, it is desirable that the proportional change by the coefficient is possible.

  According to a preferred aspect of the present invention, it is desirable that each step of the image processing method of the present invention is realized by a computer executing a program. The program is preferably recorded on a recording medium.

  According to the present invention, a digital watermark is expressed by erasing or dilating the entire solid-area object formed with the same color of an image in morphology, and the digital watermark is formed with the same color of erosion or dilation. The even / oddity of the value obtained by dividing the maximum vertical width or horizontal size of the object to be divided by the unit size value that is increased or decreased by erosion or dilation is used as 1-bit information. It is possible to improve performance such as copyright information extraction.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or that are substantially the same.

  FIG. 1 is a block diagram illustrating a configuration example of an image processing apparatus according to the present invention. As shown in FIG. 1, an image processing apparatus according to the present invention includes a CPU (central processing unit) 1, a ROM (read only memory) 2, a RAM (random access memory) 3, and a clock circuit 4. A magnetic disk device 5, a morphology unit 6, a source data encoding unit 7, a digital watermark extraction data decoding unit 8, a digital watermark embedding unit 9, a digital watermark extraction unit 10, and a morphological region determination unit 11, a CRT screen display device 12, a display control unit 13, a keyboard device 14, a screen instruction device 15, an input control unit 16, a network I / F 17, and a network transmission control unit 18. These units are connected to each other via a bus 19.

  A CPU (central processing unit) 1 controls the overall operation of the image processing apparatus. A ROM (Read Only Memory) 2 stores a program executed by the CPU 1 at startup, necessary data, and the like. A RAM (Random Access Memory) 3 is used as a work area for the CPU 1. The clock circuit 4 outputs current date information.

  The magnetic disk device 5 is for storing various data such as various application programs, work data, file data, and image data.

  The morphological unit 6 is a means for morphological erosion (dilation: image dilation) or dilation (dilation: image dilation) of a specific image area for embedding a digital watermark, and the generated data is stored in the magnetic disk device 5. And stored in the digital watermark embedding unit 9. The morphological unit 6 is also means for opening (opening) or closing (closing) in order to check the digital watermark embedding or extraction location. After the check result data is stored in the magnetic disk device 5, This is given to the watermark embedding unit 9 or the digital watermark extracting unit 10. Here, the range of the target region is instructed by the morphological region determination unit 11.

  The source data encoding unit 7 is for encrypting or encoding using data input from an external arbitrary data input means (not shown). The output data of the source data encoding unit 7 is stored in the magnetic disk device 5 and then given to the digital watermark embedding unit 9.

  The digital watermark extraction data decoding unit 8 decrypts the digital watermark extraction data stored in the magnetic disk device 5 by the digital watermark extraction unit 10 by decrypting it and stores it in another area of the magnetic disk device 5.

  The digital watermark embedding unit 9 embeds the embedded data generated by the source data encoding unit 7 into the image data to be embedded as a digital watermark. The range of the region to be embedded with the digital watermark is determined by the morphological region determination unit 11, and the digital watermark embedding is performed by the morphological unit 6.

  The digital watermark extraction unit 10 extracts a digital watermark from the image data in which the digital watermark is embedded, and stores it in another area of the magnetic disk device 5. The region range and extraction information to be subjected to digital watermark extraction are determined by the morphological region determination unit 11. The digital watermark information immediately after extraction is stored in the magnetic disk device 5 for the purpose of decoding such as decryption by the digital watermark extraction data decoding unit 8.

  The morphological region determination unit 11 determines a rectangular region in which the digital watermark information is to be embedded by erosion or dilation or from which the digital watermark information is to be extracted, and performs association with the digital watermark information. The effectiveness of the digital watermark embedding or extraction process is determined according to the check result of the morphology section 6.

  The CRT screen display device 12 is for displaying a screen for operating the image processing device. The display control unit 13 is for controlling the display content of the CRT screen display device 12.

  The keyboard device 14 is for performing various key operations on the image processing device. The screen instruction device 15 is for performing an operation such as instructing an arbitrary point on the CRT screen display device 12. The input control unit 16 is for capturing input information of the keyboard device 14 and the screen instruction device 15.

  The network I / F 17 is for connecting the image processing apparatus to a network (not shown). The network transmission control unit 18 is for performing transmission control processing for transmitting and receiving various information to and from other terminal devices via the network.

  These CPU 1, ROM 2, RAM 3, clock circuit 4, magnetic disk device 5, morphological unit 6, source data encoding unit 7, digital watermark extraction data decoding unit 8, digital watermark embedding unit 9, digital watermark extraction unit 10, The morphological region determination unit 11, the display control unit 13, the input control unit 16, and the network transmission control unit 18 are connected to a bus 19, and transmission / reception of data between these elements is mainly performed via the bus 19. Done.

  The CRT screen display device 12, the keyboard device 14, and the screen instruction device 15 realize a user interface function for the user. For example, to input various operation instructions, function selection commands, editing data, etc., to input the block size when embedding or extracting digital watermark information in image block units, or to conceal the embedded data content Thus, it is used for inputting the secret key when the digital watermark information is encrypted and when the encrypted digital watermark is decrypted. In addition, a display operation function can be realized in which the result of decoding the digital watermark is displayed superimposed on the input image image data by key operation, or only one of them is selected and displayed.

  The processed image data may be, for example, data stored in advance in the magnetic disk device 5 or data received from another terminal device or the like via a network. In addition, an optical disk device (for example, a CD-ROM drive device, a DVD drive device, etc.) to which an exchangeable storage medium can be applied, a digital still camera device, and a scanner device are provided to input processed image data. Also good.

The digital content targeted by the present invention includes information on still images, moving images, computer programs, computer data, and the like, and in particular, specific colors such as artificial images (for example, 25
This is an effective technique for embedding an electronic watermark in the case of saving in a data format that is difficult to express gradation, such as a color image or binary image that can only be used (expressed in six colors: also called limited colors and index colors).

FIG. 2 is a flowchart for explaining the digital watermark embedding process of the image processing apparatus. FIG. 3 is a flowchart for explaining the digital watermark extraction process of the image processing apparatus.
4 is a diagram showing an example of an original image (binary), FIG. 5 is a diagram showing an example of a structural element, and FIG. 6 is a diagram showing an example of dilating an original image (binary) with constituent elements. 7 is a diagram showing an example in which an original image (binary) can be dilated with constituent elements, FIG. 8 is a diagram showing an example of dilating E1 in FIG. 7, and FIG. 9 is an original image (binary with increased resolution). FIG. 10 is a diagram illustrating an example of a morphologically processed image (binary with increased resolution) of a rectangular divided image.

  An outline of a digital watermark embedding method and extraction method according to the present invention will be described with reference to the following (A) to (H). In the present invention, the ability to detect human image quality degradation utilizes the fact that shape preservation characteristic of processing according to morphology is effective in preserving edge shapes.

(A) In the present invention, a digital watermark is expressed by erasing or dilating the entire solid area object formed with the same color, and the maximum vertical length of the object formed with the same color as the erosion or dilation is included in the digital watermark. The even-oddity of the value obtained by dividing the width or width size by the unit size value that increases or decreases by erosion or dilation is used as 1-bit information.

  For example, in FIGS. 4 to 7, the result when the black pixel in FIG. 4 is dilated by the structural element in FIG. 5 is as shown in FIG. The unit size in the erosion or dilation represented by the structural element in FIG. 5 is “1” in the left and right and up and down directions. Therefore, when FIG. 4 and FIG. 6 are compared with the maximum width, for example, FIG. FIG. 6 shows 12 units. In consideration of the fact that 2 units of dilation work at both the left and right ends, the bit information obtained from the horizontal width of FIG. 4 is an odd number of 10/2 = 5. Since the bit information obtained from the horizontal width of 6 is an even number of 12/2 = 6, the bit off can be similarly expressed.

(B) In the present invention, the solid area formed with the same color is divided by regarding each area where the area boundary (edge) line is parallel to the horizontal or vertical line as a rectangular boundary, A digital watermark is expressed by independently erasing or dilating an object in the divided rectangular area. In addition, the erosion or dilation operation is performed within a range in which the coordinate value of each vertex does not change according to the conditions for cutting out the rectangle before and after the process.

  Regarding the value of the digital watermark, for example, in the case where the structural element has the contents shown in FIG. 5, the object area formed with the same color that is the object of erosion or dilation in the divided image area is regarded as a sector, and its essential ( Intersection with the boundary of the previous solid area that extends in the direction of 45 degrees close to the diagonal of the rectangle, starting from the point corresponding to (Kaname) (the intersection is flat or convex outward from the solid area) If this condition is not satisfied, the unit size that increases or decreases the Hamming distance until the distance is satisfied by extending the distance measurement and adding the Hamming distance by the erosion or dilation operation. The even-oddity of the value divided by “2” is used as 1-bit information.

  For example, as shown in FIG. 7, there are four candidates E1, E2, E3, and E4 as divided areas in which the dilation operation may be performed in FIG. When applied to E1 among them, the result of FIG. 8 is obtained. From the top right corner of the rectangle that can be determined to be the key of the fan (named), tracking with a Hamming distance in the upper left 45 degrees direction, the length before dilation is “7”, and the length after dilation is “9” It becomes. When these are converted into digital watermark values, [7/2] mod 2 = 1 and [9/2] mod 2 = 0, respectively. However, [X] is an integer itself, or otherwise, an integer closest to X that does not exceed X, and YmodZ represents a remainder when integer Y is divided by integer Z.

(C) In the present invention, regarding the degree of the erosion or dilation operation in (B) above, the object area formed with the same color as the target is regarded as a fan shape, By maximizing the intersection with the boundary of the previous solid area that extends in the direction of 45 degrees close to the diagonal, and decreasing the degree of the erosion or dilation operation toward the both ends of the fan, the solid area boundary line The effect of preventing the deterioration of the shape and the four vertex coordinates of the target rectangle do not change even after the erosion or dilation operation. For details, see step S1 (3), steps S5, S23, and S24 of the flowchart of FIG. 2 and steps S51 (3), steps S55, and S71 of FIG.

  For example, FIG. 9 shows an image obtained by increasing the resolution of the binary image in FIG. FIG. 10 is a diagram divided into rectangular regions in the same manner as described with reference to FIG. 4 and FIG. 7 to FIG. In FIG. 10, A represents an example in which the above (C) is not applied, and B represents an example in which the above (C) is applied for dilation. Here, the upper right line of the curved line drawn thickly and doublely in each of A and B in FIG. 10 is the boundary of the solid area of the original image, and the lower left line is solid after the dilation. This is the boundary line of the region. In B, the outline of the solid area is smoother even when dilation is performed.

(D) In the present invention, the solid area formed with the same color of (B) and (C) above is divided into rectangles at the places where the area boundary (edge) line is parallel to the horizontal or vertical line. In the case where two parallel portions are biased in either the horizontal or vertical direction, image quality degradation is suppressed by determining that the rectangle is not subject to digital watermarking.

  The reason for this is that the solid-coated region of this shape is likely to be excessively deteriorated in shape when an erosion or dilation operation is performed. In addition, the two parallel parts are the boundaries (edges) of solid (two or more) solid areas that are parallel to the horizontal or vertical direction in every digital watermark target area divided into rectangles. It is expressed from the existence of. For example, when enclosed in a rectangle in FIGS. 10A and 10B, the outline of the solid area is in the vertical direction (although the curvature is steep) at the upper left vertex. On the other hand, since it is in the horizontal direction at the lower right vertex (both ways of contact are not the same in the vertical and horizontal directions), it is set as a digital watermark target. However, when surrounded by a rectangle in FIG. 10C, the outline of the solid area is in the vertical direction at the top left corner (again, the curvature is steep). On the other hand, the lower right apex portion is also in contact with the vertical direction (both contact methods are the same in the vertical direction), so it is determined not to be the target of the digital watermark. In the example of FIG. 10C, the border line of the solid area is represented by two thick lines, but the line located on the lower left side represents the boundary line of the original image, and the line located on the upper right side is after the dilation. This represents the border line of the solid area. As shown in the figure, the contour line after dilation has poor smoothness at the top left corner of the rectangle.

(E) In the present invention, in the above (A) to (D), when there is no change even if the solid area object is opened or closed, the image quality deterioration is suppressed by setting it as a digital watermark target object. Since the effect of determining image quality degradation due to opening or closing is a known content, its description is omitted.

(F) In the present invention, in the above (A) to (E), the method of performing the combination of the erection or dilation operations in the vicinity of 4 and 8 near the electronic watermark target object separately in the vertical direction and the horizontal direction is a structure. It is made possible by redefining or transforming elements. Since this is also a known content, its description is omitted.

(G) In the present invention, in the above (A) to (E), the unit size to be increased or decreased representing the degree of erosion or dilation operation depends on the coefficient by configuring the coefficient representing the magnification in the structural element. Proportional change is possible. For details, see steps S23 and S24 in the flowchart of FIG. 2, step S71 of FIG. 3, and their descriptions.

(H) In the present invention, the unit size of the information in (G) above is divided by the unit size value that increases or decreases by erosion or dilation with respect to constructing a coefficient representing a magnification in a structural element in morphology. Instead of using the even-oddness of the value as 1-bit information, it is used as information of any value that can be identified in the range of 0 to (k−1) by utilizing a remainder value modulo the coefficient.

  The digital watermark embedding process of the image processing apparatus of FIG. 1 will be described with reference to the flowchart of FIG.

  In FIG. 2, in step S1, key input (input using the keyboard device 14 and the screen instruction device 14) is performed to determine the selection function, and the contents are stored in the memory (RAM 3) for the following processing. To do. Here, the selection function includes (1) secret key, (2) presence / absence of Divided Solid Area Divide (0: no division, 1: division at a position where the boundary line becomes horizontal or vertical), (3 ) Setting Smooth (0: smooth processing is not performed, 1: smooth processing is performed) setting to smoothly finish the border line of the solid coating region, (4) presence / absence of avoidance of shape deterioration processing of the S-shaped border region S_Figure (0: (5) Topology storage and shape deterioration avoidance check execution check OorC (0: unchecked, 1: checked) setting, (6) Morphological structure element B is set in a matrix (7) ) Setting the magnification k of the morphological structural element. Hereinafter, each selection function will be described in detail.

  (1) Information to be embedded as a digital watermark is pre-encrypted with a secret key (password or the like) and then embedded in the digital watermark, making it difficult to decrypt the embedded information. However, it is not essential to embed the digital watermark after always encrypting, and it is possible to select whether or not to encrypt.

  (2) An input for setting Divide / No Divide for the solid area gives an instruction to divide the following processing flow. If Divide = 0 (do not divide) is instructed, in step S3 below, the watermark embedding target is not processed in units of divided rectangular areas of solid areas (step S7). In step S10, the flow goes to step S12 for the same reason. Step S3 is a distribution process at the initial setting stage common to the whole solid area, and step S10 is a solid area individual distribution process, and the reason for the distribution is different. Exists. When Divide = 1 (division is performed where the boundary line is horizontal or vertical) is specified, in step S3, the boundary line of the solid area limited to only the solid area is smoothly finished. The instruction is determined (step S4), and in the following step S10, the process of dividing the solid area into rectangles (step S11) is determined.

  (3) An instruction for setting smooth for finishing the boundary line of the solid area is an instruction for dividing the flow of processing in the following step S4. That is, when smooth = 1, the adjustment function G (t) is set so that smooth processing is performed in step S5, and when smooth = 0, adjustment is performed so that smooth processing is not performed in step S6. A fixed value is set in the function G (t).

  (4) Presence / absence of avoidance of shape deterioration process of S-shaped boundary line area The input for setting S_Figure divides the flow of whether or not to check the shape deterioration process avoidance of S-shaped boundary line area in the following step S15. Give instructions for.

  (5) Presence / absence of execution of topology storage and shape deterioration avoidance check An input for setting OorC gives an instruction to divide the flow of processing in the determination of the following step S20.

  (6) The input for setting the morphological structural element B gives a structural element characterizing the shape in the case of erosion in step S23 or dilation in step S24.

  (7) The input for setting the magnification k of the morphological structural element is to give a strength coefficient to the structural element characterizing the shape at the time of erosion in step S23 or dilation in step S24.

  In step S2, the subject is read as a multi-valued image as an original image in which a digital watermark is embedded, and stored in a memory. This image may be a binary image.

  In step S <b> 3, it is determined whether or not division of the solid area is divided = “1”. If Divide = 1 is not satisfied (“No” in step S3), it is determined in step S7 that it is not necessary to avoid the shape deterioration process of the S-shaped boundary area. Then, the process proceeds to the process of “setting”, and 1 (fixed value) is set in the adjustment function G (t) so that the adjustment function does not work.

  If Divide = 1 (“Yes” in step S3), it is determined whether or not an instruction smooth = 1 indicating whether to smoothly finish the border line of the solid area in the divided rectangle (step S4). . If Smooth = 1 (“Yes” in step S4), processing for setting a value that is conscious of the adjustment function is performed in the adjustment function G (t) (step S5).

  Here, t: 0 to 1 corresponds to a fluctuation range, and 0 and 1 correspond to a solid region boundary line in a rectangle. G (0.5) = 1: a symmetrical function on the XY coordinates where this is the maximum value, G (0) = 0: t is monotonically increasing from 0 to 0.5, and G (1) = 0: t is A monotonic increase occurs between 0.5 and 1.

  In step S5, as shown in the above (C), the variable t varying from 0 to 1 is compared to the extent when determining the ridge line shape when the painted area divided by a rectangle is compared with a fan. Used as a variable of the function G (t) to be expressed. For example, when the shape is changed by embedding a digital watermark, the central portion of the ridge line is changed to the maximum, and no change is set at both ends of the ridge line (see FIG. 10).

  If Smooth = 1 is not satisfied (“No” in step S4), 1 (fixed value) is set to the adjustment function G (t) in a sense that the adjustment function does not work (step S6).

  In step S8, it is determined whether the flow of the entire digital watermark embedding process for each solid area is completed. If the processing for each solid area (steps S10 to S25) has been completed, the process proceeds to step 9. On the other hand, if the processing for each block has not been completed, step 10 is performed. Migrate to

  Step S 9 corresponds to the processing after the digital watermark embedding process is completed, and the digital watermark embedded image is stored in the magnetic disk device 5.

  In step S10, whether or not to divide the solid area and embed a digital watermark in the division unit is determined based on the value of “divided / not divided solid area” Divide. If Divide = 1 (“Yes” in step S10), that is, if a solid area is to be divided, the process proceeds to step S11. If Divide = 1 is not satisfied (“No” in step S10), that is, solid painting is performed. If the digital watermark (1-bit information / solid area) is embedded as a whole without dividing the area, the process proceeds to step S12.

  In step S12, as shown in (A) above, the solid area is not divided at all, and the number of divisions is set to “1” and the variable Parts = 1 is set.

  In step S11, as shown in (B) above, in order to embed a plurality of information for each solid area, the solid area is divided into rectangles, and the number of divisions of the variable Parts is set. See FIG. 10 for a specific example of the dividing method. When one solid area is divided by this method, it is divided into at least four areas (Parts is “4” or more).

  In step S13, it is determined whether or not the digital watermark embedding process for each divided area in the solid area currently being processed has been completed. Specifically, the process for each region divided in step S11 or step S12 (steps 15 to 25 below) is determined based on the value of the division number Parts. If all the processes for each block have been completed, the process proceeds to step S14. If the process has not been completed, the process proceeds to step S15.

  In step S14, it is considered that the processing of the solid area has been completed, the electronic watermark embedding target is moved to the next solid area, and the process returns to step 8.

  In step S15, it is determined whether or not to avoid the shape deterioration process of the S-shaped boundary line region according to the value of the presence or absence of the shape deterioration processing avoidance of the S-shaped boundary line region S_Figure. If it is avoided (S_Figure = 1) (“Yes” in step S15), the process proceeds to step S16. If not avoided (S_Figure? 1) (“No” in step S15), the process proceeds to step S18.

  In step S16, the directions of both ends of the boundary line of the solid coating region are examined according to (D) above. For example, sample A and B in FIG. 10 are “different” in the horizontal line direction and the vertical line direction in both ends of the solid line boundary line, but in FIG. Both have the same survey results in the vertical direction.

  In step S17, it is determined whether or not the currently handled divided area is outside the digital watermark target (whether both ends (two places) of the diagonal line of the solid area are in contact with the rectangular area in the same direction (horizontal / vertical)). . The determination method follows the investigation result of step S16. That is, in the case of “same”, the digital watermark information 1 bit to be embedded is regarded as being out of the target, and is retained in the state of being embedded in the next rectangular image. The process ends and the process proceeds to step S25. On the other hand, if “different”, it is regarded as a digital watermark embedding target, and the process proceeds to step S18.

  In step S18, it is checked whether or not the state of the rectangle in which the solid area is divided “matches” the state of the digital watermark that is desired to be embedded. In other words, if one bit of digital watermark information is extracted for the rectangle of the original image based on the structural element, it is checked whether the value is the same as the value of the one-bit information to be embedded. To do. The digital watermark information (1 bit) of the target rectangular image is determined according to (B) above.

  In step S19, it is determined whether or not the rectangular image needs to be erased or dilated based on the investigation result in step S18. If it is determined that the result of the investigation in step 18 is not “match”, it is determined that erosion or dilution is necessary, and the process proceeds to step S20. On the other hand, if it is determined that the investigation result in step S18 is “matched”, the digital image information can be regarded as valid without changing to the rectangular image, and the process proceeds to step 25.

  In step S20, it is determined by the presence / absence variable OorC set in step S1 whether or not it is necessary to perform topology storage and shape degradation avoidance check before erosion or dilation. When the presence / absence variable OorC = 1 (“Yes” in step S20), the process proceeds to step S21 in order to perform a check for avoiding topology preservation and shape deterioration according to (E) above. Also, the presence variable OorC? In the case of 1 (“No” in step S20), it is considered that the rectangular image for enabling the digital watermark embedding process can be changed, and the process proceeds to step S24.

  In step S21, as a first example of the check for avoiding topology preservation and shape degradation, the rectangular image is closed and it is determined whether or not it is the same as the original image. If the result of this determination is that it is the same as the original image, it is assumed that the rectangular image that enables the digital watermark embedding process can be changed by dilation, and the process proceeds to step 24. If it is different from the original image, it is considered that the rectangular image that enables the digital watermark embedding process cannot be changed by dilation, and the process proceeds to step S22.

  In step S22, as another example of the check for avoiding topology preservation and shape deterioration, the rectangular image is opened to determine whether it is the same as the original image. As a result, if it is the same as the original image, it is considered that the rectangular image that enables the digital watermark embedding process can be changed by erosion, and the process proceeds to step S23. If it is different from the original image, it is considered that the rectangular image for enabling the digital watermark embedding process cannot be changed (not considered as a digital watermark embedding rectangular image), and the process proceeds to step S25. Here, when the process proceeds to step S25, one bit of the digital watermark information that was to be embedded at present is kept to be embedded in the next rectangular image, and the processing of the divided rectangular area is performed. Is the end.

  In step S23, digital watermark embedding is expressed by erasing the rectangular image in accordance with (F) and (G), and the process proceeds to step S25. In step S24, the digital watermark embedding is expressed by dilating the rectangular image in accordance with the above (F) and (G), and the process proceeds to step S25.

  Here, execution of digital watermark embedding follows the following matrix operation. (B [k × G (t)])... Represents that the process by the structural element B is executed [k × G (t)] times. When it is 0, it means that the calculation by B is never executed. Also,[? ] Does not exceed? The closest integer to. This is executed with the function of the morphological structural element as a whole. However, for k, B and G (t), see step S1 above.

  However, in the opening, closing, erosion, and dilation calculation operations in steps S20 to S24, pixels that touch the boundary of the target rectangular image are treated as not changing.

  Even if step S21 is replaced with step S22 and step S24 is replaced with step S23, the embodiment is effective.

  In step S25, it is considered that the process of the divided rectangle in the solid area is finished, the electronic watermark embedding target is moved to the next rectangular image, and the process proceeds to the determination process of step S13.

  The digital watermark extraction process of the image processing apparatus of FIG. 1 will be described according to the flowchart of FIG. 3 with reference to FIGS. The flow for extracting a digital watermark during image reproduction (FIG. 3) performs the same processing in many respects as the flow for embedding a digital watermark during image capture (FIG. 2). The difference is that in the digital watermark embedding flow, the original image is changed in order to validate the digital watermark information, whereas in the digital watermark extraction flow, the image to be read is not changed. The embedded digital watermark information is extracted by analyzing.

  In FIG. 3, in step S51, in order to determine a selection function, key input (input with the keyboard D apparatus 14 and the screen instruction | indication apparatus 14 etc.) is carried out, and the content is stored in memory (RAM3) for the following processes. save. Here, the function selection includes (1) secret key, (2) presence / absence of Divided area of solid area (0: not divided, 1: divided at a position where the boundary line is horizontal or vertical), (3 ) Setting Smooth (0: smooth processing is not performed, 1: smooth processing is performed) setting to smoothly finish the border line of the solid coating region, (4) presence / absence of avoidance of shape deterioration processing of the S-shaped border region S_Figure (0: (5) Topology storage and shape deterioration avoidance check execution check OorC (0: unchecked, 1: checked) setting, (6) Morphological structure element B is set in a matrix (7) ) Setting the magnification k of the morphological structural element. For the selection functions (1) to (7) specified here, it is necessary to set the same contents as those for embedding a digital watermark. If the setting is not the same, the digital watermark embedded in the extraction target image cannot be extracted. Hereinafter, each selection function will be described in detail.

(1) When the digital watermark information is extracted with respect to an image in which the digital watermark information is embedded after the digital watermark information is previously encrypted with a secret key (password or the like), this secret key is necessary. .

(2) An input for setting Divide / No Divide for the solid area gives an instruction to divide the following processing flow. If Divide = 0 (do not divide) is instructed, the watermark embedding target is not processed in units of divided rectangular areas of the solid area in the following step S53 (step 57). In step S60, the flow goes to step S62 for the same reason. Step S53 is a distribution process at the initial setting stage common to the entire solid area, and step S60 is a distribution process for each solid area, and the reason for the distribution is different. It can exist. Also, when Divide = 1 (division where the boundary line is horizontal or vertical) is instructed, in step S53, the function of smoothly finishing the boundary line of the solid area limited to the solid area only. An instruction is judged (step 54), and in the following step S60, a solid area is divided into rectangles (step 61).

(3) An instruction for setting an instruction smooth for smoothly finishing the border line of the solid area is an instruction for dividing the flow of processing in step S54 below. That is, when smooth = 1, the adjustment function G (t) is set so that smooth processing is performed in step 55, and when smooth = 0, smooth processing is not performed in step S56. A fixed value is set in the adjustment function G (t).

(4) Presence / absence of avoidance of shape deterioration process of S-shaped boundary line area Input for setting S_Figure divides the flow of whether or not to check the shape deterioration process avoidance of S-shaped boundary line area in the following step S65. Give instructions for.

(5) Presence / absence of topology preservation and shape deterioration avoidance check The input for setting OorC gives an instruction to divide the flow of the determination process in the following step S68.

(6) The input for setting the morphological structural element B gives a structural element that characterizes a necessary shape when it is determined in step S71 whether 1-bit digital watermark information can be extracted.

(7) The input for setting the magnification k of the morphological structure element gives an intensity coefficient to the structure element characterizing the shape necessary for determining whether 1-bit digital watermark information can be extracted in step S71.

  In step S52, the target image for decoding the digital watermark is read and stored in the memory. This image may be either a multi-value image or a binary image.

  In step S <b> 53, it is determined whether or not the divided area Divide = “1”. If Divide = 1 is not satisfied (“No” in step S53), it is considered that avoiding the shape deterioration process of the S-shaped boundary area in step S57 is not necessary. The process proceeds to “Yes”, and 1 (fixed value) is set in the adjustment function G (t) in the sense that the adjustment function does not work.

  If Divide = 1 (“Yes” in step S53), it is determined whether or not an instruction Smooth = 1 indicating whether or not to smoothly finish the border line of the solid area in the divided rectangle (step S54). . If Smooth = 1 (“Yes” in step S54), a process for setting a value conscious of the adjustment function is performed in the adjustment function G (t) (step S55).

  Here, in step S55, as shown in (C) above, t: 0 to 1 corresponds to a fluctuation range, and 0 and 1 correspond to a solid area border line in a rectangle. G (0.5) = 1: a symmetrical function on the XY coordinates where this is the maximum value, G (0) = 0: t is monotonically increasing from 0 to 0.5, and G (1) = 0: t is A monotonic increase occurs between 0.5 and 1.

  A variable t that varies from 0 to 1 is used as a variable of a function G (t) that expresses a difference in degree depending on a place when determining a ridge line shape when a painted area divided by a rectangle is compared with a fan. In the case of changing the shape by embedding a digital watermark in comparison with the ridgeline of this fan, it is assumed that the central portion of the ridgeline is changed to the maximum, and both ends of the ridgeline are set so as not to change ( (See FIG. 10).

  If Smooth = 1 is not satisfied (“No” in step S54), 1 (fixed value) is set to the adjustment function G (t) in step 56 so that the adjustment function does not work (step S56).

  In step S58, the end of the flow of the entire digital watermark extraction process for each solid area is determined. When the processing for each solid area (steps S60 to S72) has been completed, the process proceeds to step S59. On the other hand, when the processing for each block has not been completed, step S60 is performed. Migrate to

  In step S59, the process after the digital watermark extraction process is completed, and the extracted digital watermark information is stored in the magnetic disk device 5.

  In step S60, whether or not to divide the solid area and extract the digital watermark in units of division is determined based on the value of “Presence / absence of division of solid area” Divide, and it is determined whether Divide = 1. . If Divide = 1 (“Yes” in step S60), the process proceeds to step S61. If Divide = 0 (“No” in step S60), the solid area is not divided and is grouped. When extracting a digital watermark (1-bit information / solid area), the process proceeds to step S62.

  In step S61, as shown in (B) above, in order to embed a plurality of information for each solid area, the solid area is divided into rectangles, and the number of divisions is set in a variable Parts. See FIG. 10 for a specific example of the dividing method. When one solid area is divided by this method, it is divided into at least four areas (parts is “4” or more).

  In step S62, as shown in (A) above, the solid area is not divided at all, and the division number is set to 1 and set to the variable Parts.

  In step S63, the end of the flow of the digital watermark embedding process in units of divided areas in the solid area currently being processed is determined. Specifically, the process for each region divided in step S61 or step S62 (hereinafter, step S65 to step S72) is determined based on the value of the division number Parts. If all the processes for each block have been completed, the process proceeds to step S64. On the other hand, if all the processes for each block have not been completed, the process proceeds to step S65.

  In step S64, it is considered that the processing of the solid area has been completed, the electronic watermark extraction target is moved to the next solid area, and the process returns to step S58.

  In step S65, it is determined whether or not to avoid the shape deterioration process of the S-shaped boundary line area according to the value of the presence or absence of the shape deterioration process avoidance of the S-shaped boundary line area S_Figure. When avoiding (S_Figure = 1) (“Yes” in step S65), the process proceeds to step S66. When avoiding (S_Figure? 1) (“No” in step S65), the process proceeds to step S68.

  In step S66, as shown in (D) above, the directions of both ends of the border line of the solid area are examined. For example, Samples A and B in FIG. 10 are “different” at both ends of the border line of the solid area in the horizontal line direction and the vertical line direction, but Sample C in FIG. Both have the same survey results in the vertical direction.

  In step S67, it is determined whether or not the currently handled divided area is outside the digital watermark target. The determination method follows the investigation result in step S66. In other words, if “same”, it is regarded as not applicable (“Yes” in step S67), and it is determined that the digital watermark information bit currently being extracted could not be extracted. On the other hand, if “different”, it is regarded as a digital watermark extraction target (“No” in step S67), and the process proceeds to step S68.

  In step S68, it is determined by the presence / absence variable OorC set in step S51 whether or not a check for avoiding topology storage and shape deterioration needs to be performed. If the presence / absence variable OorC = 1 (“Yes” in step S68), the process proceeds to step 69 for the purpose of performing a check for avoiding topology preservation and shape deterioration according to (E) above. If the presence / absence variable OorC = 1 is not satisfied (“No” in step S68), the rectangular image is regarded as a valid digital watermark extraction target, and the process proceeds to step S71.

  In step S69, as a first example of the check for avoiding topology preservation and shape deterioration, the rectangular image is closed and it is determined whether or not it is the same as the original image. If the result of this determination is the same as the original image (“Yes” in step S69), it is assumed that a digital watermark is embedded and is valid as an extraction target, and the process proceeds to step S71. If it is different from the original image (“No” in step S69), it is still unclear whether or not a digital watermark is embedded, and the process proceeds to step S70, which is another embodiment.

  In step S70, as another example of the check for avoiding topology storage and shape deterioration, the rectangular image is opened to determine whether or not it is the same as the original image. If the result of this determination is the same as the original image (“Yes” in step S70), the electronic watermark is embedded and the processing proceeds to step S71 assuming that it is valid as an extraction target. If it is different from the original image (“No” in step S70), it is regarded that the digital watermark is not embedded (not regarded as a digital watermark extraction rectangular image) and the process proceeds to step S72. Here, when the process proceeds to step 72, it is assumed that one bit of the digital watermark information that was currently being extracted could not be extracted, and the processing of the divided rectangular area is terminated.

  However, in the opening and closing calculation operations in steps S69 to S70, pixels that are in contact with the boundary of the target rectangular image are treated as not changing.

  In step S71, 1-bit digital watermark information is extracted from the target rectangular image according to (F) and (G). Here, the extraction of the digital watermark follows the following matrix operation. (B [k × G (t)])... Represents that the process by the structural element B is executed [k × G (t)] times. When it is 0, it means that the calculation by B is never executed. Also,[? ] Does not exceed? The closest integer to. This is executed with the function of the morphological structural element as a whole. However, for k, B, and G (t), see step S51 above. Thereafter, the process proceeds to step S72.

  In step S72, it is considered that the process of the divided rectangle in the solid area has been completed, the digital watermark extraction target is moved to the next rectangular image, and the process returns to the determination process of step S63.

  In the above flow, step S69 and step S70 may be interchanged.

  As described above, according to the image processing apparatus of the present embodiment, a digital watermark is expressed by performing erosion or dilation in morphology on the entire solid area object formed with the same color of the image. While using the even-oddity of the value obtained by dividing the maximum vertical or horizontal size of an object formed with the same color as an erosion or dilation by a unit size value that increases or decreases with the erosion or dilation as 1-bit information, The solid areas formed in the same color are divided into areas where the area boundary (edge) line is parallel to the horizontal or vertical line as a rectangular boundary, and objects in each divided rectangular area In, independent erosion or dilation Therefore, a digital watermark is expressed, and in the digital watermark, the movement amount of the boundary position of the object area formed with the same color as the erosion or dilation target in the divided image area is determined according to the contents of the structural element of the morphological operation. For the measurement value that captures the increase or decrease amount, the even-oddity of the value divided by the unit amount of the structural element is used as 1-bit information, so that the same color pixels are continuous for all pixel colors in the image. Since the effect of the morphological operation on the image is the same symmetrical operation in all directions, the lower / upward convex (curved) shape storage, monotonic increase / decrease storage, linear shape storage (particularly the resolution is It is possible to embed a digital watermark while suppressing the image quality deterioration while improving the image quality. An effect that it becomes possible to improve the performance of such knowledge and copyright information extraction.

(program)
Another object of the present invention is to supply a recording medium on which a program code of software for realizing the functions of the above-described image processing apparatus is recorded to a system or apparatus, and a computer (or CPU, MPU, It can also be achieved by the DSP) executing the program code stored in the recording medium. In this case, the program code itself read from the recording medium realizes the function of the above-described image processing apparatus, and the program code or the recording medium storing the program constitutes the present invention. Recording media for supplying the program code include FD, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, magnetic tape, non-volatile memory, optical recording medium such as ROM, magnetic recording medium, optical Magnetic recording media and semiconductor recording media can be used.

  Further, by executing the program code read by the computer, not only the functions of the above-described image processing apparatus are realized, but also an OS (operating system) running on the computer based on the instruction of the program code. However, it goes without saying that a case where the function of the image processing apparatus described above is realized by performing part or all of the actual processing.

  In addition, after the program code read from the recording medium is written in a memory provided in a function expansion board inserted in the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. It goes without saying that the CPU or the like provided in the board or the function expansion unit performs part or all of the actual processing and the functions of the image processing apparatus described above are realized by the processing.

  As described above, the image processing method, the image processing apparatus, the program to be executed by the computer, and the computer-readable recording medium include the recording of copyright information, the tracking of illegal copy information, the IP address History recording, prevention of illegal copying (invisible / high tolerance type), application to tampering prevention (invisible / low tolerance type), authentication, confidential communication, embedded digital content annotations and labels (visible / irreversible type, owner) This is useful for display), enabling watermark removal (visible / reversible type, content distribution), and the like.

It is a block diagram which shows the structural example of the image processing apparatus which concerns on this invention. 6 is a flowchart for explaining a digital watermark embedding process of the image processing apparatus (part 1); 12 is a flowchart for explaining a digital watermark embedding process of the image processing apparatus (part 2); 7 is a flowchart for explaining digital watermark extraction processing of the image processing apparatus (part 1); 12 is a flowchart for explaining digital watermark extraction processing of the image processing apparatus (part 2); It is a figure which shows the example of an original image (binary). It is a figure showing an example of a structural element. It is a figure which shows the example which dilated the original image (binary) with the component. It is a figure which shows the example which can dilate an original image (binary) with a component. It is a figure which shows the example which dilated E1 of FIG. It is a figure which shows the example of an original image (binary which raised the resolution). It is a figure which shows the example of the morphological process image (binary which raised the resolution) of a rectangular division image.

Explanation of symbols

1 CPU (Central Processing Unit)
2 ROM (Read Only Memory)
3 RAM (Random Access Memory)
DESCRIPTION OF SYMBOLS 6 Morphology part 7 Source data encoding part 8 Digital watermark extraction data decoding part 9 Digital watermark embedding part 10 Digital watermark extraction part 11 Morphology area determination part 12 CRT screen display device 13 Display control part 14 Keyboard device 15 Screen instruction | indication apparatus 16 Input Control unit 17 Network I / F
18 Network transmission control unit

Claims (16)

A first step of dividing a solid area formed with the same color of an image as a rectangular boundary at each area where the area boundary (edge) line is parallel to a horizontal or vertical line;
In each object in the divided rectangular area, digital watermark is expressed by independently erasing or dilating, and the digital watermark is subject to erosion or dilation in the divided image area according to the contents of the morphological operation structural element. A second step of using the even-oddity of the value divided by the unit amount of the structural element as 1-bit information for the measurement value that captures the amount of increase or decrease in the amount of movement of the boundary position of the object region formed with the same color,
An image processing method comprising: In the second step, regarding the degree of the erosion or dilation operation, the object area formed with the same color as the target is regarded as a fan shape, and is specified toward the edge of the fan from the point corresponding to the point (Kaname). maximize the intersections between the boundary (edge line) of the solid fill areas of the previously went extends in the direction, according to claim 1, characterized in that to reduce the degree of erosion or dilation operation toward the opposite ends of the fan Image processing method. In the second step, regarding the degree of the erosion or dilation operation, the object region formed with the same color as the target is regarded as a fan shape, and is 45 degrees close to the diagonal of the rectangle from the point corresponding to the point (Kaname) The intersection or intersection (ridgeline) part of the previous solid coating area extending in the direction of the maximum is maximized, and the degree of the erosion or dilation operation is reduced toward the both ends of the fan. The image processing method according to claim 2 , wherein the image processing method is 0. In the second step, the solid coating region formed in the same color is divided into rectangles at locations where the region boundary (edge) line is parallel to the horizontal or vertical direction line, and two parallel locations are 4. The image processing method according to claim 1, wherein when the image is biased in either the horizontal direction or the vertical direction, it is determined that the inside of the rectangle is not a target of digital watermark. The image according to any one of claims 1 to 4 , wherein, in the second step, when there is no change even if the solid area object is opened or closed, the object is set as a digital watermark target object. Processing method. In the second step, structural elements in morphology are defined or modified when the digital watermark target object is subjected to four or eight neighbor erosion or dilation operations separately in the vertical and horizontal directions. The image processing method according to claim 1, wherein the image processing method is performed by: In the second step, the increasing or decreasing unit size indicating the degree of the erosion or dilation operation can be proportionally changed by a coefficient by forming a coefficient indicating a magnification in a structural element in morphology. The image processing method according to claim 1, wherein the image processing method is performed. A first means for dividing a solid area formed with the same color of an image by regarding each area where the area boundary (edge) line is parallel to a horizontal or vertical line as a rectangular boundary;
In each object in the divided rectangular area, digital watermark is expressed by independently erasing or dilating, and the digital watermark is subject to erosion or dilation in the divided image area according to the contents of the morphological operation structural element. A second means for using the even-oddity of the value divided by the unit amount of the structural element as 1-bit information for the measurement value that captures the amount of increase or decrease in the amount of movement of the boundary position of the object region formed with the same color,
An image processing apparatus comprising: The second means regards the extent of the erosion or dilation operation by considering the object area formed with the same color as the target as a fan shape and specifying it toward the edge of the fan from the point corresponding to the point (Kaname) maximize the intersections between the boundary (edge line) of the solid fill areas of the previously went extends in the direction, according to claim 8, characterized in that to reduce the erosion or degree of dilation operation toward the opposite ends of the fan Image processing apparatus. The second means regards the degree of the erosion or dilation operation as an object area formed with the same color as the target as a fan shape, and is 45 degrees close to a diagonal of the rectangle from the point corresponding to the point (Kaname) The intersection or intersection (ridgeline) part of the previous solid coating area extending in the direction of the maximum is maximized, and the degree of the erosion or dilation operation is reduced toward the both ends of the fan. The image processing apparatus according to claim 9 , wherein the image processing apparatus is “0”. In the second means, the solid region formed in the same color is divided into rectangles at a region where the region boundary (edge) line is parallel to the horizontal or vertical direction line, and two parallel portions are 11. The image processing apparatus according to claim 8, wherein when the image is biased in either the horizontal direction or the vertical direction, it is determined that the inside of the rectangle is not a target of digital watermark. The image processing according to any one of claims 8 to 11 , wherein the second means sets an object to be a digital watermark when there is no change even if the solid area object is opened or closed. apparatus. The second means defines or deforms a structural element in morphology when performing the erection or dilation operation in the vicinity of 4 and 8 in the vertical direction and the horizontal direction separately for the electronic watermark target object. The image processing apparatus according to claim 8 , wherein the image processing apparatus performs the processing according to any one of claims 8 to 11 . In the second means, the increasing or decreasing unit size indicating the degree of the erosion or dilation operation can be proportionally changed by a coefficient by configuring a coefficient indicating a magnification in a structural element in morphology. The image processing apparatus according to claim 8 , wherein the image processing apparatus is an image processing apparatus. The program for making a computer perform each process of the image processing method as described in any one of Claims 1-7 . A computer-readable recording medium storing a program for causing a computer to execute each step of the image processing method according to claim 1 .

Images