JP3993111B2 - Image processing apparatus, image processing method, image processing program, and storage medium for storing image processing program - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image processing apparatus, an image processing method, an image processing program, and a storage medium for storing an image processing program for executing processing on a background dot pattern embedded in a background image included in image data of a document image.
[0002]
[Prior art]
In recent years, due to improvements in image processing technology and image forming technology, when copying banknotes and securities using a digital color copying machine, it is possible to make faithful copies that cannot be easily distinguished from the original copy. It has become. For this reason, it is necessary to take measures so that special manuscripts such as banknotes and securities cannot be copied at all or cannot be copied correctly.
[0003]
For example, even in the case of a general document other than a special manuscript such as banknotes or securities, there are many confidential documents that are prohibited from being copied from the viewpoint of maintaining confidentiality of the document contents. It is necessary to take measures to prevent such confidential documents from being copied at all, or from being copied correctly.
[0004]
For this reason, various inventions have been made in the past that aim to exert restrictions on copying special manuscripts and confidential documents. Hereinafter, specific examples of such invention will be introduced.
[0005]
First, as a method for discriminating special manuscripts such as banknotes and securities, the input image data is compared with a specific mark (pattern data) registered in advance by a pattern matching method, and a specific mark exists. A method for discriminating that a document is a special document has been proposed. The inventions described in Japanese Patent Application Laid-Open No. 6-125259 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2001-86330 (Patent Document 2) are typical examples. Thus, when it is determined that the document is a special document, it is easy to prohibit the copying, that is, not to copy.
[0006]
Next, as an invention for discriminating confidential documents that are prohibited from being copied, for example, Japanese Patent Application Laid-Open No. 7-36317 (Patent Document 3) and Japanese Patent Application Laid-Open No. 7-87309 (Patent Document 4) are attached to confidential documents. An invention is described in which a mark indicating a confidential document is detected. This utilizes the fact that a copy-prohibited confidential document is generally stamped with a mark indicating that it is a confidential document consisting of a confidential seal, a copy-prohibited mark, and the like. Thus, when it is determined that the original is a confidential document, it is easy to prohibit copying, that is, not to copy.
[0007]
Further, Japanese Patent Application Laid-Open No. 9-164939 (Patent Document 5) and Japanese Patent Application Laid-Open No. 2001-197297 (Patent Document 6) propose a technique for suppressing copying by embedding a background pattern in an original image for which copying is prohibited. Yes. This is to use a sheet on which a background pattern having a base area and a message area is created on the background of the sheet used for the original image. The copy-forgery-inhibited pattern does not stand out so much in the original image, and does not hinder the interpretation of information included in the original image. However, when a manuscript image in which such a tint block pattern is embedded is copied, for example, a message area pattern emerges. Therefore, by giving characters such as “copy prohibited” as the pattern of the message area, it becomes obvious at a glance that the copy was a confidential document prohibited from copying. Can be generated.
[0008]
[Patent Document 1]
Japanese Patent Laid-Open No. 6-125259
[Patent Document 2]
JP 2001-86330 A
[Patent Document 3]
JP-A-7-36317
[Patent Document 4]
JP 7-87309 A
[Patent Document 5]
Japanese Patent Laid-Open No. 9-164739
[Patent Document 6]
JP 2001-197297 A
[0009]
[Problems to be solved by the invention]
As described above, the input image data is compared with a specific mark (pattern data) registered in advance by the pattern matching method, and if it matches, special copying such as banknotes and securities is prohibited. Can be prevented from being copied. However, if copying is prohibited by such a method, all pattern data of the original to be prohibited from copying must be registered in advance. Therefore, even if it is effective for special manuscripts such as banknotes and securities, it is extremely difficult to apply it to an unspecified number of general manuscripts such as confidential documents.
[0010]
Further, as described above, copying of a confidential document can be prevented by prohibiting copying when a mark indicating a confidential document such as a confidential mark is detected. However, in this case, when an image reading operation is executed with a mark portion indicating a confidential document such as a confidential mark covered with paper or the like, it is a confidential document as a matter of course. Therefore, there is a problem that it is not possible to determine the presence of a mark indicating that the copying cannot be prevented even if the confidential document should be prohibited from being copied.
[0011]
Further, as described above, for example, a confidential document is generated as a manuscript image in which a background pattern is embedded in the background, and when such a confidential document is copied, a part of the background pattern emerges. Psychologically, the ability to regulate copying can be generated. However, such a method using a tint block pattern only provides a copy suppression effect, and does not restrict the copying act itself. For this reason, there is a problem that a confidential document can be copied for a person who does not mind that the tint block pattern is raised.
[0012]
An object of the present invention is to reliably prevent a confidential document reproduction process.
[0013]
[Means for Solving the Problems]
The image processing apparatus according to claim 1 is configured to calculate a frequency distribution of the adjacent black run center distances included in the image data of the document image, and to output the calculated frequency distribution as a feature amount. Detecting means for detecting whether a background dot pattern to be prohibited is embedded in a background image included in the image data.
[0014]
Here, “black run” means, for example, a portion where dots are continuous. Therefore, in the case of the present invention, a vertical or horizontal line in which dots constituting a background dot pattern or the like are continuous can be interpreted as a black run. For this reason, it can be said that the “adjacent black run center distance” is the distance between the centers of the dots constituting the background dot pattern or the like. For this reason, the “frequency distribution of adjacent black run center distances” means the frequency distribution obtained for the center-to-center distances of the dots constituting the background dot pattern and the like. The frequency distribution in this case is a distribution of the number of the distances between the centers of the dots constituting the background dot pattern or the like. The interpretations of “black run”, “adjacent black run center distance”, and “frequency distribution of adjacent black run center distance” are common throughout the present specification.
[0015]
Therefore, it is detected whether the background dot pattern that prohibits output is included in the image data of the document image regardless of the type of document image.
[0016]
According to a second aspect of the present invention, in the image processing apparatus according to the first aspect, the calculation means executes binarization processing of the image data prior to calculation of the frequency distribution.
[0017]
Accordingly, it is easy to calculate the frequency distribution of adjacent black run center distances included in the image data of the document image.
[0018]
According to a third aspect of the present invention, in the image processing apparatus according to the first aspect, the background dot pattern includes a base area and a message area, and the detection means uses the peak value of the frequency distribution calculated by the calculation means as a feature amount. The base area reference peak value that is the peak value of the black run center distance frequency distribution for the base area included in the background dot pattern that is prohibited from output, and the message area reference that is the peak value of the black run center distance frequency distribution for the message area Referring to the peak value, it is detected whether or not a background dot pattern for prohibiting the output is included in the image data.
[0019]
Accordingly, it is detected whether the base area of the background dot pattern for which output is prohibited is included in the image data when the peak value of the frequency distribution calculated by the calculating means does not match the base area reference peak value. Further, it is detected whether or not the image data includes a message area of a background dot pattern for which output is prohibited based on a coincidence / mismatch between the peak value of the frequency distribution calculated by the calculating means and the message area reference peak value.
[0020]
According to a fourth aspect of the present invention, in the image processing apparatus according to the third aspect, the detection unit determines whether the peak value of the frequency distribution calculated by the calculation unit matches the base region reference peak value; And determining whether the number of peak values of the frequency distribution calculated when the coincidence is determined exceeds a threshold set for the base region reference peak value. It is detected whether the base area of the background dot pattern to be prohibited is included in the image data.
[0021]
Therefore, not only does the coincidence between the peak value of the frequency distribution calculated by the calculation means and the base region reference peak value, but the number of peak values of the calculated frequency distribution exceeds the threshold set for the base region reference peak value. It is also determined whether or not the image data includes a base region of a background dot pattern that prohibits output with higher accuracy.
[0022]
According to a fifth aspect of the present invention, in the image processing apparatus according to the third aspect, the detection means determines a match between the peak value of the frequency distribution calculated by the calculation means and the message area reference peak value; And determining whether the number of peak values of the frequency distribution calculated when the coincidence is determined exceeds a threshold set for the message region reference peak value. It is detected whether or not a message area of a background dot pattern to be prohibited is included in the image data.
[0023]
Therefore, not only the coincidence and mismatch between the peak value of the frequency distribution calculated by the calculation means and the message area reference peak value, but also the number of peak values of the calculated frequency distribution exceeds the threshold set for the message area reference peak value. Whether or not the image data includes a message area of a background dot pattern that prohibits output with higher accuracy is detected.
[0024]
According to a sixth aspect of the present invention, in the image processing apparatus according to the first aspect, is the background dot pattern included in the image data a background dot pattern that prohibits output based on a detection result of the detection means. Judgment means for judging whether or not is provided.
[0025]
Therefore, it is possible to determine whether output of image data of a document image should be prohibited regardless of the type of document image.
[0026]
According to a seventh aspect of the present invention, in the image processing apparatus according to the third, fourth and fifth aspects, the background dot pattern included in the image data prohibits output based on the detection result of the detection means. Judgment means for judging whether it is a pattern or not is provided.
[0027]
Therefore, it is possible to determine whether output of image data of a document image should be prohibited regardless of the type of document image.
[0028]
According to an eighth aspect of the present invention, in the image processing apparatus according to the seventh aspect, the determination means detects the base area of a background dot pattern that prohibits the output from being included in the image data. Included in the image data is that either or both of the result and the detection result of the detection means that the message area of the background dot pattern that prohibits the output is included in the image data are included The determined background dot pattern is a background dot pattern that prohibits output.
[0029]
Therefore, it becomes easy to determine whether or not output of image data of a document image should be prohibited.
[0030]
The invention of the image processing method according to claim 9 is a calculation step of calculating a frequency distribution of adjacent black run center distances included in the image data of the original image using hardware resources, and using hardware resources, And a detection step of detecting whether a background dot pattern that prohibits output is embedded in a background image included in the image data using the calculated frequency distribution as a feature amount.
[0031]
Therefore, it is detected whether the background dot pattern that prohibits output is included in the image data of the document image regardless of the type of document image.
[0032]
The invention according to claim 10 is installed in a computer, and the computer has a calculation function for calculating the frequency distribution of adjacent black run center distances included in the image data of the original image, and the calculated frequency distribution as a feature quantity. And a detection function for detecting whether or not a background dot pattern for prohibiting output is embedded in a background image included in the image data.
[0033]
Therefore, it is detected whether the background dot pattern that prohibits output is included in the image data of the document image regardless of the type of document image.
[0034]
The invention described in claim 11 is installed in a computer, and the computer has a calculation function for calculating the frequency distribution of adjacent black run center distances included in the image data of the original image, and the calculated frequency distribution as a feature quantity. And a detection function for detecting whether or not a background dot pattern for prohibiting output is embedded in a background image included in the image data, and a storage medium for storing a machine-readable computer program for executing the computer program .
[0035]
Therefore, it is detected whether the background dot pattern that prohibits output is included in the image data of the document image regardless of the type of document image. In addition, the computer program can be handled in the form of a tangible object.
[0036]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS.
[0037]
1. Original image
First, document images used in the image processing apparatus, the image processing method, and the like according to the present embodiment will be described with reference to FIGS.
[0038]
FIG. 1 is a front view illustrating a document image. FIG. 2 is a schematic diagram showing an example of a copy of an original image in which a tint block pattern as a background dot pattern embedded in the original image appears. Of course, the tint block pattern is an aspect of the background dot pattern, and it goes without saying that the background dot pattern can have a dot pattern other than the tint block pattern.
[0039]
FIG. 3 is a schematic diagram showing another example of a copy of the original image in which the tint block pattern embedded in the original image is seen floating. FIG. 4 is an enlarged schematic diagram illustrating the tint block pattern illustrated in FIG. 3. FIG. 5 is an enlarged schematic diagram illustrating the tint block pattern illustrated in FIG.
[0040]
In the example shown in FIG. 1, the original paper 102 in which the background pattern 103 is embedded in the background is used as the original paper 102 for creating the original image 101 that is a contract. However, as another embodiment, the copy-forgery-inhibited pattern 103 may be formed at the same time as the original image 101 that is a contract is created using the original paper 102 on which the copy-forgery-inhibited pattern 103 is not formed. That is, the copy-forgery-inhibited pattern 103 may be preliminarily printed on the original paper 102 or may be simultaneously formed when characters, graphics, etc. are formed on the original paper 102.
[0041]
The tint block pattern 103 includes a base area 104 and a message area 105. The base area 104 is a ground area that occupies most of the original paper 102. The message area 105 is an area for expressing a message distributed in the base area 104. The base area 104 and the message area 105 are not different from each other in the basic configuration of the tint block pattern 103 itself, and are divided into the base area 104 and the message area 105 as human value judgment for the tint block pattern 103. It ’s just that. In the present embodiment, the message area 105 is composed of characters “copy prohibited”. As characters constituting such a message area 105, any characters, symbols, and the like can be used in addition to “copy prohibited”.
[0042]
In the original image 101 created using such original paper 102, when the original image 101 is copied or the like, a part of the tint block pattern 103 emerges. In this case, in the document image 101 illustrated in FIG. 2, the message area 105 expressed by the characters “copy prohibited” appears, and in the document image 101 illustrated in FIG. 3, the base area 104 appears.
[0043]
As described above, when the original image 101 with the copy-forgery-inhibited pattern 103 embedded therein is copied, one of the message area 105 and the base area 104 in the copy-forgery-inhibited pattern 103 appears, and the other area 104 or 105 is copied. This is because it is difficult to (reproduce). In other words, when the region 104 or 105 that does not rise up disappears, the remaining region 104 or 105 appears to rise up.
[0044]
The tint block pattern 103 that causes such a phenomenon is constituted by a set of two types of dots 106 having different sizes, as illustrated in FIGS. 4 and 5, for example. That is, of these two types of dots 106, the small dots 106b are difficult to be copied (reproduced), and the large dots 106a are copied (reproduced). Therefore, in the copy-forgery-inhibited pattern 103 illustrated in FIG. 2 in which the message area 105 rises after copying, as shown in FIG. 5, a small dot 106 b is used for the base area 104, and a larger one for the message area 105. Dots 106a are used. On the other hand, in the tint block pattern 103 illustrated in FIG. 3 in which the base area 104 rises after copying, as shown in FIG. 4, a small dot 106 b is used in the message area 105, and the base area 104 is formed. Large dots 106a are used.
[0045]
As another configuration example of the tint block pattern 103, the message area 105 or the base area 104 that emerges can be configured not only by dots but also by a thin line pattern, a specific pattern pattern, or the like.
[0046]
Here, in the present embodiment, the message area 105 or the base area 104 is treated as a feature amount. In this case, the frequency distribution of adjacent black run center distances can be used as a feature amount for a black run that occurs when the message area 105 or the base area 104 that emerges, that is, a portion where dots are continuous. The frequency distribution here is a distribution of the number of the distances between the centers of the dots constituting the message area 105 or the base area 104.
[0047]
In the above example, the feature quantity for the message area 105 or the base area 104 that emerges is limited. However, as such a feature quantity, the base area 104 or the message area 105 that does not emerge, or the message area 105 or the base area 104 that emerges. For each of the base region 104 or the message region 105 that does not appear, the respective feature amounts may be obtained. In short, if one or both of the base area 104 and the message area 105 can be read as data when the original image 101 in which the image data in which the tint block pattern 103 is embedded is recorded is read, Can be treated as a feature quantity. Or, in the image data in which the copy-forgery-inhibited pattern 103 existing in the form of data is embedded, if either or both of the base area 104 and the message area 105 constituting the copy-forgery-inhibited pattern 103 can be read as data, Can be treated as a feature quantity.
[0048]
As another embodiment, as described above, it can be said that the background dot pattern has a pattern other than the tint block pattern 103. For example, a pattern corresponding to only the base area 104 in the background pattern 103 or a pattern corresponding to only the message area 105 can be used. If the original image 101 having a pattern corresponding to the base area 104 or a pattern corresponding to the message area 105 is read, if the base area 104 or the message area 105 can be read as data, it is treated as a feature amount. It is possible. Alternatively, in image data in which a background dot pattern having a pattern corresponding to the base area 104 existing in the form of data or a pattern corresponding to the message area 105 is embedded, it corresponds to the base area 104 constituting the background dot pattern 103. If a pattern or a pattern corresponding to the message area 105 can be read as data, it can be handled as a feature amount.
[0049]
2. Image processing method
In the image processing method of the present embodiment, the frequency distribution of adjacent black run center distances included in the image data of the original image 101 is calculated using a hardware resource such as a digital circuit or a computer (calculation step). Whether the tint block pattern 103 (either one or both of the base area 104 and the message area 105) whose output is prohibited by using the calculated frequency distribution as a feature amount is embedded in the background image included in the image data. Detect (detection step).
[0050]
In the detecting step, after the detecting step, it is determined whether or not the detected tint block pattern 103 is a tint block pattern 103 whose output is prohibited by using hardware resources (determination step). The determination in this case is made based on whether or not the image data of the document image 101 includes one or both of the base area 104 and the message area 105 of the copy-forgery-inhibited pattern 103 for which output is prohibited. That is, if one or both of the base area 104 and the message area 105 of the copy-forgery-inhibited pattern 103 for which output is prohibited is included in the image data of the document image 101, the document image 101 regardless of the type of the document image 101. It is determined that the output of the image data 101 should be prohibited.
[0051]
3. Image processing device
[0052]
(1) First embodiment of image processing apparatus
A first embodiment of an image processing apparatus according to the present invention will be described with reference to FIGS.
[0053]
FIG. 6 is a block diagram illustrating hardware resources of the image processing apparatus. FIG. 7 is a block diagram of the tint block pattern detection unit shown in FIG. FIG. 8 is a schematic view illustrating the black run center distance between adjacent dots included in image data. FIG. 9 is a histogram of the frequency distribution of adjacent black run center distances included in the tint block pattern whose output should be prohibited.
[0054]
As shown in FIG. 6, the image processing apparatus according to the present embodiment has a digital copying machine configuration in which a scanner 201 as an image reading apparatus, an image processing unit 202 having a digital circuit configuration, and a plotter 203 are controlled by a system controller 204. ing. The system controller 204 utilizes computer functions constructed from a built-in CPU (Central Processing Unit) 204a, ROM (Read Only Memory) 204b, and RAM (Random Access Memory) 204c, and responds to an instruction from the operation display unit 205. The scanner 201, the image processing unit 202, and the plotter 203 are controlled to return necessary information to the operation display unit 205 for display.
[0055]
The image processing unit 202 includes a filter processing unit 206, a scaling processing unit 207, a γ processing unit 208, and a gradation processing unit 209. These units 206, 207, 208, and 209 are not different from the equivalent circuit configuration provided in a general digital copying machine, and thus the description thereof is omitted.
[0056]
On the other hand, the image processing unit 202 of the present embodiment includes a tint block pattern detection unit 210, a copy-inhibited document determination unit 211, and a selector 212. These copy-forgery-inhibited pattern detection unit 210, copy prohibition document determination unit 211, and selector 212 are hardware with a digital circuit configuration that detects and determines a copy prohibition document such as a confidential document and prohibits the copy.
[0057]
The tint block pattern detection unit 210 has a hardware configuration illustrated in FIG. 7. That is, image data based on the original image 101 read by the scanner 201 is binarized by the binarization processing unit 251 as necessary. Subsequently, the frequency distribution detection unit 252 calculates the black run center distance in the binarized image data, and calculates the frequency distribution based on the calculated black run center distance. Such a calculation process is executed by a counter or an adder having a digital circuit configuration.
[0058]
Here, the tint block pattern detection unit 210 includes a base region determination unit 253 and a message region determination unit 254 subsequent to the frequency distribution detection unit 252. Each of these base area determination unit 253 and message area determination unit 254 has a storage area (not shown).
[0059]
The storage area of the base area determination unit 253 stores the peak value (base area reference peak value) in the frequency distribution of the black run center distance and the base area reference peak value of the base area 104 of the tint block pattern 103 whose output should be prohibited. Store the threshold. Here, the threshold value refers to the peak of the frequency distribution calculated when the peak value of the frequency distribution of the black run center distance in the image data calculated by the frequency distribution detection unit 252 matches the base region reference peak value. If the number of values exceeds the threshold value of the base area reference peak value, the image data is a threshold value that should be determined as including the base area 104 of the tint block pattern 103 that should not be output. Note that the state in which the peak value of the frequency distribution of the black run center distance in the image data calculated by the frequency distribution detection unit 252 matches the base region reference peak value allows a certain amount of error.
[0060]
On the other hand, the storage area of the message area determination unit 254 stores the peak value (message area reference peak value) in the frequency distribution of the black run center distance and the message area reference peak for the message area 105 of the tint block pattern 103 whose output should be prohibited. Store the threshold value. The threshold here means that the peak value of the frequency distribution calculated when the frequency distribution peak value of the black run center distance in the image data calculated by the frequency distribution detection unit 252 matches the message region reference peak value. If the number of values exceeds the threshold value of the message area reference peak value, the image data is a threshold value that should be determined as including the message area 105 of the tint block pattern 103 that should not be output. The state where the peak value of the frequency distribution of the black run center distance in the image data calculated by the frequency distribution detection unit 252 matches the message region reference peak value allows a certain amount of error.
[0061]
FIG. 9 shows a histogram of the frequency distribution of adjacent black run center distances included in the tint block pattern whose output should be prohibited. In the histogram shown in FIG. 9, regarding the base area 104 of the tint block pattern 103 whose output should be prohibited, there are two peak values (base area reference peak values) in the frequency distribution of the black run center distance, b and c. Illustrated. As a result, it can be seen that there are two types of dot patterns in the base region 104 of the tint block pattern 103 that should be prohibited from being output. In the histogram shown in FIG. 9, the message area 105 of the tint block pattern 103 whose output should be prohibited has only one peak value (message area reference peak value) in the frequency distribution of the black run center distance. Is illustrated. As a result, it can be seen that there is only one type of dot pattern in the message area 105 of the copy-forgery-inhibited pattern 103 that should be prohibited from being output.
[0062]
The base area determination unit 253 refers to the frequency distribution of the black run center distance in the image data calculated by the frequency distribution detection unit 252 as a feature amount, and stores the peak value of the frequency distribution in its own storage area. The output is compared with the peak value (base region reference peak value) in the frequency distribution of the black run center distance for the base region 104 of the tint block pattern 103 to be prohibited. As a result of the comparison, if the two peak values (the detected peak value and the base region reference peak value) match, the number of peak values of the calculated frequency distribution exceeds the threshold value of the base region reference peak value. If it exceeds, the image data is determined to include the base area 104 of the tint block pattern 103 that should be prohibited from being output. That is, here, it is detected whether the image data calculated by the frequency distribution detection unit 252 includes data corresponding to the base region 104 of the tint block pattern 103 that should not be output. The base area determination unit 253 outputs the determination result to the copy prohibited document determination unit 211.
[0063]
One message area determination unit 254 refers to the frequency distribution of the black run center distance in the image data calculated by the frequency distribution detection unit 252 as a feature amount, and stores the peak value of the frequency distribution in its own storage area. The output is compared with the peak value (message area reference peak value) in the frequency distribution of the black run center distance for the message area 105 of the tint block pattern 103 to be prohibited. As a result of the comparison, when the two peak values (the detected peak value and the message area reference peak value) match, the number of peak values of the calculated frequency distribution exceeds the threshold of the message area reference peak value. If it exceeds it, it is determined that the image data includes the message area 105 of the tint block pattern 103 that should not be output. That is, here, it is detected whether the image data calculated by the frequency distribution detection unit 252 includes data corresponding to the message area 105 of the tint block pattern 103 that should not be output. The message area determination unit 254 outputs the determination result to the copy prohibited document determination unit 211.
[0064]
In this way, the binarization processing unit 251 and the frequency distribution detection unit 252 execute the function (calculation step) of the calculation means for calculating the frequency distribution of the adjacent black run center distances included in the image data of the original image. Detection means for detecting whether or not the background pattern included in the image data is embedded in the background image by using the calculated frequency distribution as a feature amount by the base region determination unit 253 and the message region determination unit 254 The function (detection step) is executed. As a result, it is detected whether the copy-forgery-inhibited pattern pattern that prohibits output is included in the image data of the document image.
[0065]
The copy-inhibited document determination unit 211 receives the processing result of the copy-forgery-inhibited pattern detection unit 210 and executes a copy-prohibited document determination process according to a predetermined determination criterion. This determination criterion may be stored as a parameter in a storage area (not shown) provided in the copy-prohibited document determination unit 211, for example, or may be set in such a storage area by an input from the operation display unit 205. For example, the copy-prohibited document determination unit 211 is a copy-prohibited document such as a confidential document when one of the base area 104 and the message area 105 of the copy-forgery-inhibited pattern 103 exists in the original image 101 read by the scanner 201. Judge that there is. Alternatively, the copy-prohibited document determination unit 211 is a copy-prohibited document such as a confidential document when both the base area 104 and the message area 105 of the copy-forgery-inhibited pattern 103 exist in the original image 101 read by the scanner 201. Judge that there is. Here, based on the detection result of the detection means, the function (determination step) of the determination means for determining whether the copy-forgery-inhibited pattern included in the image data is a copy-forgery-inhibited pattern that is prohibited from being output.
[0066]
When the copy-prohibited document determination unit 211 determines that the original image 101 read by the scanner 201 is a copy-prohibited document, the copy-prohibited document determination unit 211 transmits to the selector 212 of the image processing unit 202 that a copy-prohibited document has been detected. In response to this, the selector 212 selects processing after detection of the copy-prohibited document, that is, prohibition of the copy operation in the plotter 203. Thereby, when the original image 101 read by the scanner 201 is a copy-inhibited document such as a confidential document, the copy (reproduction) is prevented.
[0067]
(2) Second embodiment of image processing apparatus (image processing program, storage medium for storing image processing program)
A second embodiment of the image processing apparatus (image processing program, storage medium storing the image processing program) of the present invention will be described with reference to FIGS.
[0068]
FIG. 10 is a block diagram illustrating hardware resources of the image processing apparatus. FIG. 11 is a flowchart showing the flow of copy-prohibited document discrimination processing executed by a computer program installed in the hardware resource of the image processing apparatus.
[0069]
In the image processing apparatus shown as the first embodiment, an example is shown in which a copy prohibition document such as a confidential document is detected and determined, and the process of prohibiting the copy is executed by hardware resources of a digital circuit configuration. . On the other hand, in the present embodiment, a copy-prohibited document such as a confidential document is detected and determined, and the process for prohibiting the copy is executed by a computer program installed in the hardware resource of the image processing apparatus. An example will be described. Therefore, the same parts as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0070]
In the present embodiment, the copy-forgery-inhibited pattern detection unit 210, the copy-inhibited document determination unit 211, and the selector 212 are not provided in the image processing unit 202, and a copy-inhibited document such as a confidential document is stored in the ROM 204b of the system controller 204. Is stored and stored as firmware. As another embodiment, a copy prohibition document such as a confidential document is detected and determined in the HDD 213 connected to a microcomputer constructed from the CPU 204a, ROM 204b, and RAM 204c provided in the system controller 204, and the copy is made. A configuration may be adopted in which a computer program for processing for prohibiting the image processing is installed and such a computer program is written and executed in the RAM 204c when the image processing apparatus is activated. In any case, the process of detecting and determining a copy-prohibited document such as a confidential document and prohibiting the copy is executed by the system controller 204, which is a computer, according to the computer program. In this sense, the RAM 204c or the HDD 213 functions as a storage medium that stores a computer program that is an image processing program.
[0071]
Hereinafter, processing executed in accordance with such a computer program will be described with reference to a flowchart shown in FIG.
[0072]
First, the processing routine shown in FIG. 11 is executed at a certain time, and it is repeatedly determined whether or not the original image 101 is read by the scanner 201 and image data is input (step S101).
[0073]
When it is determined that the original image 101 is read by the scanner 201 and the image data is input (Y in step S101), for example, the input image data is copied into the image memory included in the memory represented by the comprehensive concept of the RAM 204c. (Step S102).
[0074]
On the other hand, if it is not determined that the original image 101 has been read by the scanner 201 (N in step S101), whether the original image 101 has been read by the scanner 201 and image data has been input. Wait for the decision.
[0075]
Then, the image data copied to such an image memory is binarized by the arithmetic function of the CPU 204a (step S103), and then a process for obtaining the frequency distribution of the black run center process is executed (step S104). . Here, the function (calculation step) of the calculation means for calculating the frequency distribution of the adjacent black run center distances included in the image data of the document image is executed.
[0076]
Here, in the present embodiment, a value serving as a reference for the tint block pattern 103 that should be prohibited from being output is stored in a nonvolatile memory or a battery backup memory (storage area) included in the memory represented by the comprehensive concept of the RAM 204c. .
[0077]
That is, for the base area 104 of the tint block pattern 103 whose output is prohibited, the peak value (base area reference peak value) in the frequency distribution of the black run center distance and the threshold value of the base area reference peak value are stored. The threshold here means that when the peak value of the frequency distribution of the black run center distance in the image data obtained in step S104 matches the base region reference peak value, the number of peak values of the calculated frequency distribution is If the threshold value of the base area reference peak value is exceeded, the image data is a threshold value that should be determined to include the base area 104 of the tint block pattern 103 that should not be output. Note that the state in which the peak value of the frequency distribution of the black run center distance in the image data calculated by the frequency distribution detection unit 252 matches the base region reference peak value allows a certain amount of error.
[0078]
Further, for the message area 105 of the tint block pattern 103 to be prohibited from being output, the peak (message area reference peak value) in the frequency distribution of the black run center distance and the threshold value of the message area reference peak value are stored. The threshold here means that when the peak value of the frequency distribution of the black run center distance in the image data obtained in step S104 matches the message region reference peak value, the number of peak values of the calculated frequency distribution is If the threshold value of the message area reference peak value is exceeded, the image data is a threshold value that should be determined to include the message area 105 of the tint block pattern 103 that should not be output. The state where the peak value of the frequency distribution of the black run center distance in the image data calculated by the frequency distribution detection unit 252 matches the message region reference peak value allows a certain amount of error.
[0079]
Note that the reference values (base region reference peak value and threshold value thereof, message region reference peak value and threshold value thereof) of the copy-forgery-inhibited pattern 103 that should be prohibited from being output are nonvolatile memories included in the memory represented by the comprehensive concept of the RAM 204c. However, as another embodiment, such a value may be stored in, for example, the HDD 213 (storage area). In this case, various data stored in the HDD 213 (storage area) may be copied to the RAM 204c together with a computer program describing a routine for this processing from the HDD 213 to the RAM 204c. It may be maintained in a stored state.
[0080]
In subsequent step S105, the frequency distribution of the black run center distance in the image data calculated in step S104 is referred to as a feature amount, and the peak value of the frequency distribution is the base region reference peak value stored in the storage region, that is, It is compared with the peak value in the frequency distribution of the black run center distance for the base region 104 of the tint block pattern 103 whose output is to be prohibited. That is, here, it is detected whether or not the image data calculated in step S104 includes data corresponding to the base region 104 of the tint block pattern 103 that should not be output.
[0081]
As a result of the detection in step S105, if it is determined that the peak value of the frequency distribution of the black run center distance in the image data calculated in step S104 matches the base region reference peak value (Y in step S105), it is obtained in step S104. It is determined whether the number of peak values of the frequency distribution of the black run center distance in the image data exceeds the threshold value of the base region reference peak value (step S106). As a result of this determination, if it is determined that it does not exceed, the process is terminated. If it is determined that it exceeds (Y in step S106), it is determined that there is a base area 104 of the tint block pattern 103 whose output is prohibited. Judgment is made (step S107), and the judgment result is passed to the copy-prohibited document judgment process (step S111).
[0082]
On the other hand, as a result of the detection in step S105, it is determined that the peak value of the frequency distribution of the black run center distance in the image data calculated in step S104 does not match the base region reference peak value (N in step S105). ), The frequency distribution of the black run center distance in the image data calculated in step S104 is referred to as a feature amount, and the peak value of the frequency distribution is stored in the storage area as a message area reference peak value, that is, output is prohibited. It is compared with the peak value in the frequency distribution of the black run center distance for the message area 105 of the background pattern 103 to be processed (step S108). That is, here, it is detected whether or not the image data calculated in step S104 includes data corresponding to the message area 105 of the copy-forgery-inhibited pattern 103 that should not be output.
[0083]
As a result of the detection in step S108, when it is determined that the peak value of the frequency distribution of the black run center distance in the image data calculated in step S104 does not coincide with the message region reference peak value (N in step S105), the process ends. To do.
[0084]
On the other hand, as a result of the detection in step S108, when it is determined that the peak value of the frequency distribution of the black run center distance in the image data calculated in step S104 matches the message region reference peak value (Y in step S105). Then, it is determined whether or not the number of peak values of the frequency distribution of the black run center distance in the image data obtained in step S104 exceeds the threshold value of the message area reference peak value (step S109). As a result of this determination, if it is determined that it does not exceed, the process is terminated, and if it is determined that it exceeds (Y in step S109), there is a message area 105 of the tint block pattern 103 whose output is prohibited. Judgment is made (step S110), and the judgment result is passed to a copy-prohibited document judgment process (step S111).
[0085]
In this way, the function (detection step, detection function) of the detection means that detects whether the background pattern pattern that prohibits output is embedded in the background image included in the image data using the calculated frequency distribution as a feature amount is executed. Will be. As a result, it is detected whether the copy-forgery-inhibited pattern pattern that prohibits output is included in the image data of the document image.
[0086]
In the copy-prohibited document determination process in step S111, the copy-prohibited document determination process is executed according to a predetermined determination criterion. This determination criterion may be stored as a parameter in, for example, a nonvolatile memory or a battery backup memory (storage area) included in a memory represented by the comprehensive concept of the RAM 204c, and the RAM 204c ( Storage area) may be temporarily set. Thus, in the copy-prohibited document determination process in step S113, as an example, when one of the base area 104 and the message area 105 of the copy-forgery-inhibited pattern 103 to be output is present in the original image 101 read by the scanner 201. It is determined that the document is a copy-inhibited document such as a confidential document. Alternatively, as another example, when both the base area 104 and the message area 105 of the copy-forgery-inhibited pattern 103 that should be prohibited from being output exist in the original image 101 read by the scanner 201, the copy prohibition such as a confidential document is prohibited. Judge as a document. Here, based on the detection result of the detection means, the function (determination step) of the determination means for determining whether the copy-forgery-inhibited pattern included in the image data is a copy-forgery-inhibited pattern that is prohibited from being output.
[0087]
When the copy-prohibited document determination process in step S113 determines that the original image 101 read by the scanner 201 is a copy-prohibited document, the process after the copy-prohibited document is detected, that is, the copy operation in the plotter 203 is prohibited. Execute. Thereby, when the original image 101 read by the scanner 201 is a copy-inhibited document such as a confidential document, the copy (reproduction) is prevented.
[0088]
Further, what kind of copy-forgery-inhibited pattern pattern 103 the copy of the original image 101 is prohibited is stored and saved in a nonvolatile memory or a battery backup memory (storage area) included in a memory represented by the comprehensive concept of the RAM 204c. This depends on the reference values (base area reference peak value and threshold value thereof, message area reference peak value and threshold value thereof) of the tint block pattern 103 that should be prohibited from being output. For this reason, if such a threshold value can be arbitrarily set, it is possible to designate the tint block pattern 103 embedded in the document image 101 for designating copy prohibition.
[0089]
Therefore, the computer program according to the present embodiment acquires the image data of the copy-forgery-inhibited pattern 103 when the original image 101 or the original paper 102 in which the copy-forgery-inhibited pattern 103 is embedded is read by the scanner 201 and the image data of the copy-forgery-inhibited pattern 103 is acquired. In response to the above, values (base area reference peak value and threshold value thereof, message area reference peak value and threshold value) serving as a reference of the tint block pattern 103 to be prohibited from being output as described above are automatically generated and stored in the RAM 204c (storage area). The process of storing and saving is executed. Accordingly, the background pattern 103 can be registered as the background pattern 103 whose output is prohibited only by reading the background pattern 103 whose output is prohibited by the scanner 201 serving as the document reading apparatus.
[0090]
(3) Third embodiment of image processing apparatus (image processing program, storage medium for storing image processing program)
A third embodiment of the image processing apparatus (image processing program, storage medium storing the image processing program) of the present invention will be described with reference to FIGS.
[0091]
FIG. 12 is a block diagram illustrating hardware resources of the image processing apparatus. FIG. 12 is a flowchart showing a copy-prohibited document determination process executed by a computer program installed in the hardware resource of the image processing apparatus.
[0092]
In the second embodiment, an image processing apparatus has been described in which a copy-prohibited document such as a confidential document is detected and determined, and the process for prohibiting the copy is executed by a computer program installed in hardware resources. This image processing apparatus is, for example, a digital copying machine as described in the first embodiment. On the other hand, in the present embodiment, the second point is that the processing for detecting and determining a copy-prohibited document such as a confidential document and forbidding the copy is executed by a computer program installed in the hardware resource. This embodiment is similar to the second embodiment, but differs from the second embodiment in that a general personal computer 301 is used as such hardware resources. However, the computer program itself is basically not different from the computer program used in the second embodiment. Therefore, the same parts as those of the first embodiment and the second embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0093]
The personal computer 301 includes a CPU 204a that centrally controls each unit. In the CPU 204a, a ROM 204b that is a read-only memory storing a BIOS and the like, a rewritable storage of various data, a work area of the CPU 204a, and the like. Is connected to the RAM 204c functioning as a bus 302 to form a microcomputer. Further, the bus 302 includes an HDD 213 in which a computer program that is an image processing program is installed, a CD-ROM drive 304 that reads data recorded in the CD-ROM 303, and an interface 305 that controls communication with a printer unit and the like. It is connected.
[0094]
As an example, a computer program that is an image processing program installed in the HDD 213 is originally recorded on the CD-ROM 303, and the computer program is read by the CD-ROM drive 304 by the CPU 204 a and installed in the HDD 213. It is. When the computer program installed in the HDD 213 is activated, the computer program is copied from the HDD 213 to the RAM 204c and executed by the CPU 204a and the RAM 204c. In this sense, the RAM 204c, HDD 213, or CD-ROM 303 functions as a storage medium that stores a computer program that is an image processing program.
[0095]
However, as a storage medium for storing the computer program, not only the CD-ROM 303 but also various media such as various optical disks such as DVD, various magnetic disks such as various magneto-optical disks and flexible disks, semiconductor memory, and the like are used. Can do. Further, a computer program may be downloaded from a network such as the Internet and installed in the HDD 213. In this case, the storage device that stores the computer program in the server on the transmission side is also a storage medium in the present invention. The program may operate on a predetermined OS (Operating System), in which case the OS may execute a part of various processes described later, or a word processor. It may be included as part of a group of program files that constitute predetermined application software such as software or an OS.
[0096]
Hereinafter, processing executed according to the computer program installed in the HDD 213 will be described with reference to a flowchart shown in FIG. This process is almost the same as the process in the second embodiment described with reference to FIG. 9, but will be described without being omitted for the sake of clarity.
[0097]
First, the processing routine shown in FIG. 13 is executed at a certain time, and it is repeatedly determined whether image data based on the document image 101 has been input (step S201).
[0098]
If it is determined that image data has been input (Y in step S201), the input image data is copied into an image memory included in a memory represented by a generic concept such as the RAM 204c (step S102).
[0099]
On the other hand, if it is not determined that image data has been input (N in step S201), the process waits for determination of whether image data has been input.
[0100]
Then, the image data copied to such an image memory is binarized by the arithmetic function of the CPU 204a (step S103), and then a process for obtaining the frequency distribution of the black run center process is executed (step S104). . Here, the function (calculation step) of the calculation means for calculating the frequency distribution of the adjacent black run center distances included in the image data of the document image is executed.
[0101]
Here, in the present embodiment, a reference value of the tint block pattern 103 to be prohibited from being output is stored in a nonvolatile memory or a battery backup memory (storage area) included in a memory represented by the comprehensive concept of the RAM 204c. .
[0102]
That is, for the base area 104 of the tint block pattern 103 whose output is prohibited, the peak value (base area reference peak value) in the frequency distribution of the black run center distance and the threshold value of the base area reference peak value are stored. The threshold here means that when the peak value of the frequency distribution of the black run center distance in the image data obtained in step S104 matches the base region reference peak value, the number of peak values of the calculated frequency distribution is If the threshold value of the base area reference peak value is exceeded, the image data is a threshold value that should be determined to include the base area 104 of the tint block pattern 103 that should not be output. Note that the state in which the peak value of the frequency distribution of the black run center distance in the image data calculated by the frequency distribution detection unit 252 matches the base region reference peak value allows a certain amount of error.
[0103]
Further, for the message area 105 of the tint block pattern 103 to be prohibited from being output, the peak (message area reference peak value) in the frequency distribution of the black run center distance and the threshold value of the message area reference peak value are stored. The threshold here means that when the peak value of the frequency distribution of the black run center distance in the image data obtained in step S104 matches the message region reference peak value, the number of peak values of the calculated frequency distribution is If the threshold value of the message area reference peak value is exceeded, the image data is a threshold value that should be determined to include the message area 105 of the tint block pattern 103 that should not be output. The state where the peak value of the frequency distribution of the black run center distance in the image data calculated by the frequency distribution detection unit 252 matches the message region reference peak value allows a certain amount of error.
[0104]
Note that the reference values (base region reference peak value and threshold value thereof, message region reference peak value and threshold value thereof) of the copy-forgery-inhibited pattern 103 that should be prohibited from being output are nonvolatile memories included in the memory represented by the comprehensive concept of the RAM 204c. However, as another embodiment, such a value may be stored in, for example, the HDD 213 (storage area). In this case, various data stored in the HDD 213 (storage area) may be copied to the RAM 204c together with the computer program describing the routine for this processing from the HDD 213 to the RAM 204c. It may be maintained in a stored state.
[0105]
In subsequent step S105, the frequency distribution of the black run center distance in the image data calculated in step S104 is referred to as a feature amount, and the peak value of the frequency distribution is the base region reference peak value stored in the storage region, that is, It is compared with the peak value in the frequency distribution of the black run center distance for the base region 104 of the tint block pattern 103 whose output is to be prohibited. That is, here, it is detected whether or not the image data calculated in step S104 includes data corresponding to the base region 104 of the tint block pattern 103 that should not be output.
[0106]
As a result of the detection in step S105, if it is determined that the peak value of the frequency distribution of the black run center distance in the image data calculated in step S104 matches the base region reference peak value (Y in step S105), it is obtained in step S104. It is determined whether the number of peak values of the frequency distribution of the black run center distance in the image data exceeds the threshold value of the base region reference peak value (step S106). As a result of this determination, if it is determined that it does not exceed, the process is terminated. If it is determined that it exceeds (Y in step S106), it is determined that there is a base area 104 of the tint block pattern 103 whose output is prohibited. Judgment is made (step S107), and the judgment result is passed to the copy-prohibited document judgment process (step S111).
[0107]
On the other hand, as a result of the detection in step S105, it is determined that the peak value of the frequency distribution of the black run center distance in the image data calculated in step S104 does not match the base region reference peak value (N in step S105). ), The frequency distribution of the black run center distance in the image data calculated in step S104 is referred to as a feature amount, and the peak value of the frequency distribution is stored in the storage area as a message area reference peak value, that is, output is prohibited. It is compared with the peak value in the frequency distribution of the black run center distance for the message area 105 of the background pattern 103 to be processed (step S108). That is, here, it is detected whether or not the image data calculated in step S104 includes data corresponding to the message area 105 of the copy-forgery-inhibited pattern 103 that should not be output.
[0108]
As a result of the detection in step S108, when it is determined that the peak value of the frequency distribution of the black run center distance in the image data calculated in step S104 does not coincide with the message region reference peak value (N in step S105), the process ends. To do.
[0109]
On the other hand, as a result of the detection in step S108, when it is determined that the peak value of the frequency distribution of the black run center distance in the image data calculated in step S104 matches the message region reference peak value (Y in step S105). Then, it is determined whether or not the number of peak values of the frequency distribution of the black run center distance in the image data obtained in step S104 exceeds the threshold value of the message area reference peak value (step S109). As a result of this determination, if it is determined that it does not exceed, the process is terminated, and if it is determined that it exceeds (Y in step S109), there is a message area 105 of the tint block pattern 103 whose output is prohibited. Judgment is made (step S110), and the judgment result is passed to a copy-prohibited document judgment process (step S111).
[0110]
In this way, the function (detection step, detection function) of the detection means that detects whether the background pattern pattern that prohibits output is embedded in the background image included in the image data using the calculated frequency distribution as a feature amount is executed. Will be. As a result, it is detected whether the copy-forgery-inhibited pattern pattern that prohibits output is included in the image data of the document image.
[0111]
In the copy-prohibited document determination process in step S111, the copy-prohibited document determination process is executed according to a predetermined determination criterion. This determination criterion may be stored as a parameter in, for example, a nonvolatile memory or a battery backup memory (storage area) included in a memory represented by the comprehensive concept of the RAM 204c, and the RAM 204c ( Storage area) may be temporarily set. Thus, in the copy-prohibited document determination process in step S113, as an example, when one of the base area 104 and the message area 105 of the copy-forgery-inhibited pattern 103 to be output is present in the original image 101 read by the scanner 201. It is determined that the document is a copy-inhibited document such as a confidential document. Alternatively, as another example, when both the base area 104 and the message area 105 of the copy-forgery-inhibited pattern 103 that should be prohibited from being output exist in the original image 101 read by the scanner 201, the copy prohibition such as a confidential document is prohibited. Judge as a document. Here, based on the detection result of the detection means, the function (determination step) of the determination means for determining whether the copy-forgery-inhibited pattern included in the image data is a copy-forgery-inhibited pattern that is prohibited from being output.
[0112]
In the copy-prohibited document determination process in step S113, if it is determined that the original image 101 read by the scanner 201 is a copy-prohibited document, the process after the copy-prohibited document is detected, that is, the copy operation in the plotter 203 is prohibited. Execute. Thereby, when the original image 101 read by the scanner 201 is a copy-inhibited document such as a confidential document, the copy (reproduction) is prevented.
[0113]
Further, what kind of copy-forgery-inhibited pattern pattern 103 the copy of the original image 101 is prohibited is stored and saved in a nonvolatile memory or a battery backup memory (storage area) included in a memory represented by the comprehensive concept of the RAM 204c. This depends on the reference values (base area reference peak value and threshold value thereof, message area reference peak value and threshold value thereof) of the tint block pattern 103 that should be prohibited from being output. For this reason, if such a threshold value can be arbitrarily set, it is possible to designate the tint block pattern 103 embedded in the document image 101 for designating copy prohibition.
[0114]
Therefore, the computer program according to the present embodiment acquires the image data of the copy-forgery-inhibited pattern 103 when the original image 101 or the original paper 102 in which the copy-forgery-inhibited pattern 103 is embedded is read by the scanner 201 and the image data of the copy-forgery-inhibited pattern 103 is acquired. In response to the above, values (base area reference peak value and threshold value thereof, message area reference peak value and threshold value) serving as a reference of the tint block pattern 103 to be prohibited from being output as described above are automatically generated and stored in the RAM 204c (storage area). The process of storing and saving is executed. Accordingly, the background pattern 103 can be registered as the background pattern 103 whose output is prohibited only by reading the background pattern 103 whose output is prohibited by the scanner 201 serving as the document reading apparatus.
[0115]
【The invention's effect】
The image processing apparatus according to claim 1 is configured to calculate a frequency distribution of the adjacent black run center distances included in the image data of the document image, and to output the calculated frequency distribution as a feature amount. Detecting means for detecting whether a background dot pattern to be prohibited is embedded in a background image included in the image data, so that output is performed on the image data of the original image regardless of the type of the original image. It is possible to detect whether a prohibited background dot pattern is included.
[0116]
According to a second aspect of the present invention, in the image processing apparatus according to the first aspect, the calculation means executes binarization processing of the image data prior to calculation of the frequency distribution. The frequency distribution of the adjacent black run center distances included can be easily calculated.
[0117]
According to a third aspect of the present invention, in the image processing apparatus according to the first aspect, the background dot pattern includes a base area and a message area, and the detection means uses the peak value of the frequency distribution calculated by the calculation means as a feature amount. The base area reference peak value that is the peak value of the black run center distance frequency distribution for the base area included in the background dot pattern that is prohibited from output, and the message area reference that is the peak value of the black run center distance frequency distribution for the message area Since it is detected whether or not a background dot pattern that prohibits the output is included in the image data with reference to the peak value, the peak value of the frequency distribution calculated by the calculation means and the base region reference peak value do not match To detect whether the base area of the background dot pattern that prohibits output is included in the image data Further, it is detected whether the image data includes a message area of a background dot pattern that prohibits output based on a coincidence / mismatch between the peak value of the frequency distribution calculated by the calculation means and the message area reference peak value. be able to.
[0118]
According to a fourth aspect of the present invention, in the image processing apparatus according to the third aspect, the detection unit determines whether the peak value of the frequency distribution calculated by the calculation unit matches the base region reference peak value; And determining whether the number of peak values of the frequency distribution calculated when the coincidence is determined exceeds a threshold set for the base region reference peak value. Since it is detected whether the base area of the background dot pattern to be prohibited is included in the image data, not only the coincidence mismatch between the peak value of the frequency distribution calculated by the calculation means and the base area reference peak value, but also the calculated frequency It can also be determined whether the number of peak values in the distribution exceeds the threshold set for the base region reference peak value, and therefore more accurate. It can be the base region of the background dot pattern that prohibits force detecting whether included in the image data.
[0119]
According to a fifth aspect of the present invention, in the image processing apparatus according to the third aspect, the detection means determines a match between the peak value of the frequency distribution calculated by the calculation means and the message area reference peak value; And determining whether the number of peak values of the frequency distribution calculated when the coincidence is determined exceeds a threshold set for the message region reference peak value. Since it detects whether the message area of the background dot pattern to be prohibited is included in the image data, not only the coincidence mismatch between the peak value of the frequency distribution calculated by the calculation means and the message area reference peak value, but also the calculated frequency It is also possible to determine whether the number of distribution peak values exceeds the threshold set for the message region reference peak value. It can be a message region of the well background dot pattern that prohibits output to detect whether it contains the image data.
[0120]
According to a sixth aspect of the present invention, in the image processing apparatus according to the first aspect, is the background dot pattern included in the image data a background dot pattern that prohibits output based on a detection result of the detection means. Since the determination means for determining whether or not the document image is output, it is possible to determine whether the output of the image data of the document image should be prohibited regardless of the type of the document image.
[0121]
According to a seventh aspect of the present invention, in the image processing apparatus according to the third, fourth and fifth aspects, the background dot pattern included in the image data prohibits output based on the detection result of the detection means. Since the judging means for judging whether the pattern is a pattern or not is provided, it is possible to judge whether the output of the image data of the document image should be prohibited regardless of the type of the document image.
[0122]
According to an eighth aspect of the present invention, in the image processing apparatus according to the seventh aspect, the determination means detects the base area of a background dot pattern that prohibits the output from being included in the image data. Included in the image data is that either or both of the result and the detection result of the detection means that the message area of the background dot pattern that prohibits the output is included in the image data are included Since the determined background dot pattern is a background dot pattern that prohibits output, it is possible to easily determine whether or not output of image data of a document image should be prohibited.
[0123]
The invention of the image processing method according to claim 9 is a calculation step of calculating a frequency distribution of adjacent black run center distances included in the image data of the original image using hardware resources, and using hardware resources, And a detecting step for detecting whether a background dot pattern that prohibits output is embedded in the background image included in the image data, using the calculated frequency distribution as a feature amount. It is possible to detect whether or not a background dot pattern that prohibits output is included in the image data of the original image.
[0124]
The invention according to claim 10 is installed in a computer, and the computer has a calculation function for calculating the frequency distribution of adjacent black run center distances included in the image data of the original image, and the calculated frequency distribution as a feature quantity. And a detection function for detecting whether or not a background dot pattern that prohibits output is embedded in the background image included in the image data, and a machine-readable computer program that executes the invention. Regardless of the type, it is possible to detect whether the image data of the document image includes a background dot pattern that prohibits output.
[0125]
The invention described in claim 11 is installed in a computer, and the computer has a calculation function for calculating the frequency distribution of adjacent black run center distances included in the image data of the original image, and the calculated frequency distribution as a feature quantity. And a detection function for detecting whether or not a background dot pattern for prohibiting output is embedded in a background image included in the image data, and a storage medium for storing a machine-readable computer program for executing the computer program Therefore, regardless of the type of document image, it is possible to detect whether the image data of the document image includes a background dot pattern that prohibits output, and it is possible to handle computer programs in the form of tangible objects. , The convenience of handling can be enhanced.
[Brief description of the drawings]
FIG. 1 is a front view illustrating a document image.
FIG. 2 is a schematic diagram illustrating an example of a copy of an original image in which a tint block pattern embedded in the original image is seen floating.
FIG. 3 is a schematic diagram showing another example of a copy of an original image in which a tint block pattern embedded in the original image appears floating.
4 is an enlarged schematic diagram illustrating the tint block pattern illustrated in FIG. 3. FIG.
5 is an enlarged schematic diagram illustrating the tint block pattern illustrated in FIG. 2. FIG.
FIG. 6 is a block diagram showing hardware resources as the first embodiment of the image processing apparatus of the present invention;
7 is a block diagram of a tint block pattern detection unit shown in FIG. 6. FIG.
FIG. 8 is a schematic view illustrating the black run center distance of adjacent dots included in image data.
FIG. 9 is a histogram of a frequency distribution of adjacent black run center distances included in a tint block pattern whose output should be prohibited.
FIG. 10 is a block diagram showing hardware resources as the second embodiment of the image processing apparatus of the present invention;
FIG. 11 is a flowchart illustrating a copy-prohibited document determination process executed by a computer program installed in hardware resources of the image processing apparatus.
FIG. 12 is a block diagram showing hardware resources as a third embodiment of the image processing apparatus of the present invention;
FIG. 13 is a flowchart illustrating a copy-prohibited document determination process executed by a computer program installed in the hardware resource of the image processing apparatus.
[Explanation of symbols]
101 Document image
103 Background dot pattern (background pattern)
104 Base area
105 Message area
204c, 213 Storage area (RAM, HDD)

Claims (11)

Calculating means for calculating a frequency distribution of adjacent black run center distances included in the image data of the document image;
Detection means for detecting whether or not a background dot pattern that prohibits output is embedded in a background image included in the image data, using the calculated frequency distribution as a feature amount;
An image processing apparatus comprising: The image processing apparatus according to claim 1, wherein the calculation unit executes binarization processing of the image data prior to calculation of the frequency distribution. The background dot pattern includes a base area and a message area, and the detection means uses the peak value of the frequency distribution calculated by the calculation means as a feature amount, and the black run center distance relating to the base area included in the background dot pattern that prohibits output A background dot pattern that prohibits the output with reference to a base area reference peak value that is a peak value of the frequency distribution of the message and a message area reference peak value that is a peak value of the frequency distribution of the black run center distance regarding the message area is the image The image processing apparatus according to claim 1, wherein the image processing apparatus detects whether the data is included. The detecting means determines whether the peak value of the frequency distribution calculated by the calculating means matches the base area reference peak value, and the number of peak values of the frequency distribution calculated when the match is determined. Whether or not a base region of a background dot pattern that prohibits the output is included in the image data by executing whether or not a threshold set for the base region reference peak value is exceeded The image processing apparatus according to claim 3, wherein: The detection means determines whether the peak value of the frequency distribution calculated by the calculation means matches the message area reference peak value, and the number of peak values of the frequency distribution calculated when the match is determined. Whether or not the image data includes a message area of a background dot pattern that prohibits the output by executing whether or not a threshold set for the message area reference peak value is exceeded. The image processing apparatus according to claim 3, wherein: The image processing apparatus according to claim 1, further comprising: a determination unit that determines whether a background dot pattern included in the image data is a background dot pattern that prohibits output based on a detection result of the detection unit. 6. The determination unit according to claim 3, further comprising: a determination unit configured to determine whether a background dot pattern included in the image data is a background dot pattern that prohibits output based on a detection result of the detection unit. Image processing device. The determination means includes a detection result of the detection means that a base area of a background dot pattern that prohibits the output is included in the image data, and a message area of a background dot pattern that prohibits the output in the image data. It is determined that the background dot pattern included in the image data is a background dot pattern that prohibits output when either or both of the detection results of the detection means that it is included are included. The image processing apparatus according to claim 7. A calculation step of calculating a frequency distribution of adjacent black run center distances included in the image data of the original image using hardware resources;
A detection step of detecting whether or not a background dot pattern that prohibits output is embedded in a background image included in the image data, using the hardware resources as a feature amount and a calculated frequency distribution;
An image processing method comprising: A calculation function that is installed in a computer and calculates a frequency distribution of adjacent black run center distances included in the image data of the original image;
A detection function for detecting whether a background dot pattern that prohibits output is embedded in a background image included in the image data, using the calculated frequency distribution as a feature amount;
A machine-readable computer program that executes the program. A calculation function that is installed in a computer and calculates a frequency distribution of adjacent black run center distances included in the image data of the original image;
A detection function for detecting whether a background dot pattern that prohibits output is embedded in a background image included in the image data, using the calculated frequency distribution as a feature amount;
A storage medium for storing a machine-readable computer program that executes the program.

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