JP2017163372A - Image processor and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve efficiency of detection processing for detecting whether or not a specific original is included in image data acquired by an image processor.SOLUTION: An image processor 2 comprises: a resolution calculation part 34 for, on the basis of attached information 50 attached to image data D1 acquired by an image acquisition part 30, calculating subject resolution of a subject included in the image data D1; a detection part 38 for detecting a feature pattern of a specific original from the image data D1; and a determination part 36 for determining whether to cause the detection part 38 to detect the feature pattern in accordance with the subject resolution calculated by the resolution calculation part 34. The detection part 38 detects the feature pattern on the basis of a determination result by the determination part 36.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an image processing apparatus and a program, and more particularly to a technique for detecting a specific manuscript such as banknotes and securities included in image data.

  In order to prevent forgery, specific pattern images such as banknotes and securities are embedded with characteristic pattern images that are difficult to understand visually. An image processing apparatus such as an MFP (Multifunction Peripherals), for example, when copying and outputting a document with a copy function, determines whether or not the feature pattern of the specific document is included in the image data read from the document. If the characteristic pattern is included, forgery of the specific document is prevented by canceling the execution of the job or by painting and outputting at least a part of the image (for example, Patent Document 1). .

  This type of image processing apparatus stores in advance data relating to a feature pattern of a specific document, and whether or not a specific document is included in the image data by performing a process of detecting the feature pattern on the input image data. Whether or not can be detected. In particular, when a specific original is read by the scan function, the resolution of the specific original included in the image data can be grasped based on the scan settings such as the original size, the enlargement / reduction ratio, and the reading resolution. In this case, the image processing apparatus can perform feature pattern detection processing in accordance with the resolution of the specific document, and efficiently and accurately detect whether or not the specific document is included in the image data. can do.

JP 2006-246097 A

  Incidentally, an image processing apparatus such as an MFP can input and print not only image data read by a scan function but also various image data. Therefore, the image processing apparatus executes a process of determining whether or not the various input image data includes the feature pattern of the specific document.

  However, for example, in the case of image data obtained by shooting a specific original using a digital camera, the image processing apparatus cannot specify the size of the specific original in the image data. For this reason, if a feature pattern detection process is simply performed in accordance with the resolution of the image data, there is a possibility of detection omission. This is because the image data is included in the case of an enlarged image shot with only a part of the specific document in the shooting range of the digital camera and a reduced image shot with the entire specified document set in a part of the shooting range. This is because the number of dots of the specific document is different.

  Conventional image processing apparatuses execute detection processing for input image data a plurality of times while changing the resolution of the feature pattern to be detected in order to prevent the above-described detection omissions. It was difficult to complete.

  Accordingly, the present invention has been made to solve such problems, and an object thereof is to provide an image processing apparatus and a program that can efficiently perform a feature pattern detection process on image data.

  In order to achieve the above object, the invention according to claim 1 is directed to an acquisition unit that acquires image data and an object included in the image data based on attached information included in the image data acquired by the acquisition unit. Resolution detection means for calculating subject resolution, detection means for detecting a feature pattern of a specific document from the image data acquired by the acquisition means, and detection means according to the subject resolution calculated by the resolution calculation means Determining means for determining whether or not to perform the process of detecting the feature pattern from the image data, and the detecting means performs a process of detecting the feature pattern based on a determination result by the determination means. It is characterized by doing.

  According to a second aspect of the present invention, in the image processing apparatus according to the first aspect, the determination unit does not perform the process of detecting the feature pattern when the subject resolution is less than a predetermined limit value. It is possible to make a determination, and the detection unit does not perform a process of detecting the feature pattern based on a determination result by the determination unit.

  According to a third aspect of the present invention, in the image processing apparatus according to the second aspect, the print control unit that causes the printing unit to print the image data acquired by the acquisition unit based on a predetermined print resolution, and the detection unit. And a print restriction unit that prohibits execution of printing by the print control unit when the feature pattern is detected from the image data.

  According to a fourth aspect of the present invention, in the image processing apparatus according to the third aspect, the determination means has the subject resolution equal to or higher than the limit value, and the subject resolution is equal to or lower than a predetermined value with respect to the print resolution. If it is, it is determined that the process for detecting the feature pattern is not performed by the detection unit, and the detection unit does not perform the process for detecting the feature pattern based on a determination result by the determination unit. It is characterized by.

  According to a fifth aspect of the present invention, in the image processing apparatus according to the third or fourth aspect, the detection unit performs a process of detecting the feature pattern based on the print resolution.

  According to a sixth aspect of the present invention, in the image processing apparatus according to any one of the second to fifth aspects, the determination unit performs a process of detecting the feature pattern from the first image data by the detection unit. And the process of detecting the feature pattern from the second image data when the subject resolution calculated from the second image data different from the first image data is less than the limit value. It is determined that the detection is not performed, and the detection unit does not perform a process of detecting the feature pattern from the second image data based on a determination result by the determination unit.

  According to a seventh aspect of the present invention, in the image processing device according to any one of the first to sixth aspects, the attached information includes subject distance information between the imaging device and a subject, lens focal length information of the imaging device, and the The resolution information of the image sensor in the imaging device is included, and the resolution calculation unit calculates the subject resolution using the subject distance information, the lens focal length information, and the resolution information.

  The invention according to claim 8 is the image processing apparatus according to any one of claims 1 to 7, further comprising resolution conversion means capable of converting the resolution of the image data acquired by the acquisition means, and the detection means. Performs a process of detecting the feature pattern from the image data at a predetermined detection resolution, and the resolution conversion unit is configured to detect a difference between the subject resolution calculated from the image data and the detection resolution equal to or greater than a predetermined value. The resolution of the image data is converted so that the subject resolution becomes the same value as the detection resolution, and the detection means detects the feature pattern from the image data after the resolution is converted by the resolution conversion means. It is characterized by that.

  The invention according to claim 9 is a program executed in an image processing apparatus capable of acquiring and outputting image data, wherein the image processing apparatus is acquired by acquisition means for acquiring image data and the acquisition means. Resolution calculating means for calculating subject resolution of a subject included in the image data based on attached information included in the image data, detection means for detecting a feature pattern of a specific document from the image data acquired by the acquiring means, and , Functioning as determination means for determining whether or not to cause the detection means to perform processing for detecting the feature pattern from the image data in accordance with the subject resolution calculated by the resolution calculation means, and the detection means Is characterized in that a process for detecting the feature pattern is performed based on a determination result by the determination means.

  According to a tenth aspect of the present invention, in the program according to the ninth aspect, the determination unit can determine that the process of detecting the feature pattern is not performed when the subject resolution is less than a predetermined limit value. And the detection means does not perform the process of detecting the feature pattern based on the determination result by the determination means.

  The invention according to claim 11 is the program according to claim 10, wherein the image processing apparatus causes the printing means to print the image data obtained by the obtaining means based on a predetermined print resolution, and When the feature pattern is detected from the image data by the detection means, the print control means is further functioned as a print restriction means for prohibiting execution of printing by the print control means.

  According to a twelfth aspect of the present invention, in the program according to the eleventh aspect, the determination means has the subject resolution equal to or higher than the limit value, and the subject resolution is equal to or lower than a predetermined value with respect to the print resolution. In this case, it is determined that the process for detecting the feature pattern is not performed by the detection unit, and the detection unit does not perform the process for detecting the feature pattern based on a determination result by the determination unit. It is said.

  According to a thirteenth aspect of the present invention, in the program according to the eleventh or twelfth aspect, the detection means performs a process of detecting the feature pattern based on the print resolution.

  According to a fourteenth aspect of the present invention, in the program according to any one of the tenth to thirteenth aspects, the determination unit performs a process of detecting the feature pattern from the first image data by the detection unit. In addition, when the subject resolution calculated from the second image data different from the first image data is less than the limit value, a process of detecting the feature pattern from the second image data is performed. The detection unit determines that the feature pattern is not detected from the second image data based on the determination result of the determination unit.

  According to a fifteenth aspect of the invention, in the program according to any one of the ninth to fourteenth aspects, the attached information includes subject distance information between an imaging device and a subject, lens focal length information of the imaging device, and the imaging device. The resolution information of the imaging unit included in the image is included, and the resolution calculation unit calculates the subject resolution using the subject distance information, the lens focal length information, and the resolution information.

  According to a sixteenth aspect of the present invention, in the program according to any one of the ninth to fifteenth aspects, the image processing device further functions as a resolution conversion unit capable of converting the resolution of the image data acquired by the acquisition unit. The detection means performs a process of detecting the feature pattern from the image data with a predetermined detection resolution, and the resolution conversion means has a difference between the subject resolution and the detection resolution equal to or greater than a predetermined value. The resolution of the image data is converted so that the subject resolution becomes the same value as the detection resolution, and the detection means detects the feature pattern from the image data after the resolution is converted by the resolution conversion means. It is characterized by.

  According to the present invention, it is determined whether or not to perform the feature pattern detection process of the specific document according to the subject resolution of the subject included in the image data. Therefore, it is possible to limit the image data to be subjected to the detection process. it can. As a result, the efficiency of the detection process can be improved.

It is a figure which shows the example of 1 structure of the image processing system provided with the image processing apparatus. It is a figure which shows an example of the to-be-photographed object at the time of imaging | photography. It is a figure which shows an example of the image | photographed image data. It is a figure which shows one structural example of attached information. It is a block diagram which shows an example of the hardware constitutions and functional structure of an image processing apparatus. It is a figure which shows an example of the imaging magnification calculated on various imaging conditions, and a to-be-photographed resolution. It is a flowchart which shows an example of the main processing procedures performed in an image processing apparatus. It is a flowchart which shows an example of the detailed process sequence of a subject resolution determination process. It is a flowchart which shows an example of the detailed process sequence of a resolution conversion process.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, in embodiment described below, the same code | symbol is attached | subjected to the member which is mutually common, and the overlapping description about them is abbreviate | omitted.

  FIG. 1 is a diagram illustrating a configuration example of an image processing system 1 including an image processing apparatus 2 according to an embodiment of the present invention. The image processing system 1 includes an image processing device 2 configured by, for example, an MFP, and an imaging device 3 configured by a digital camera. The image processing apparatus 2 includes a scanner unit 14 that optically reads an image of a document to generate image data, and a printer unit 15 that forms an image on a print medium such as a print sheet based on the image data and prints it out. I have. The imaging device 3 has, for example, a shooting function and a communication function, and can transmit image data generated by the shooting function to the outside by the communication function. Therefore, the image processing apparatus 2 can acquire the image data D1 captured by the imaging apparatus 3, and can perform printout based on the image data D1. However, the method in which the image processing device 2 acquires the image data D1 from the imaging device 3 may not be based on the communication function. For example, the image data D1 may be acquired via a memory card or the like, or the image data D1 captured by the imaging device 3 may be acquired via another information device such as a personal computer. Also good.

  For example, as illustrated in FIG. 1, the imaging device 3 may generate image data D1 obtained by photographing a specific document P1 such as a banknote or a securities that is a forgery prevention target in the image processing device 2 as a subject. Therefore, when the image processing apparatus 2 acquires the image data D1 captured by the imaging apparatus 3, the image data D1 may include the document image G1 of the specific document P1. Therefore, the image processing apparatus 2 is configured to prohibit printing output based on the image data D1 including the document image G1 of the specific document P1 and storing such image data. The

  The image processing apparatus 2 stores in advance a sample image of a feature pattern to be detected for each specific document such as banknotes and securities that are to be prevented from forgery. This sample image is, for example, image data having a resolution that matches a reading resolution that can be set when the scanner unit 14 reads a document, or a printing resolution that is used when the printer unit 15 performs printing output. Then, when the image processing apparatus 2 acquires the image data, the image processing apparatus 2 performs a process of determining whether or not the acquired image data includes an image of a specific document such as a banknote or a securities. That is, the image processing apparatus 2 performs a detection process for detecting the feature pattern of the specific document on the acquired image data, thereby determining whether or not the specific document is included in the image data. In this detection process, for example, a process of detecting a specific pattern by matching a sample image with acquired image data is performed.

  For example, when image data is acquired by reading a document with the scanner unit 14, the image processing apparatus 2 specifies the resolution of the specific document included in the image data based on the scan setting at the time of reading the document, and the specified specification By performing a feature pattern detection process using a sample image that matches the resolution of the document, it is determined whether or not the specific document is included in the image data.

  On the other hand, when the image data D1 captured by the imaging device 3 is acquired, the image processing device 2 cannot apply the same processing as the detection processing for the image data obtained by the scan function. This is because the image data D1 photographed by the imaging device 3 does not know what size the specific document P1 is captured.

  FIG. 2 is a diagram illustrating the state of the subject when the image is taken by the imaging device 3. FIG. 2A shows a case where the specific original P1 is arranged at a relatively large size in the photographing range 100 of the image pickup apparatus 3 and photographed. In this case, the image data D1 includes the document image G1 of the specific document P1 in a relatively large area at the center. On the other hand, FIG. 2B includes the foreground subject F1 and the background subject F2 within the shooting range 100 of the imaging apparatus 3, and the specific document P1 is arranged in a relatively small size on a part of the foreground subject F1. This shows the case of shooting. In the case of FIG. 2B, the original image G1 of the specific original P1 is included in a small area of the image data D1, and the number of pixels in which the specific original P1 is reflected is smaller than in the case of FIG. Become. That is, as shown in FIG. 2A, the resolution of the specific document P1 included in the image data D1 when the specific document P1 is shot at a relatively large size as shown in FIG. Is higher than the resolution of the specific document P1 included in the image data D1 when the image is captured at a relatively small size. Hereinafter, in the present embodiment, the resolution of the specific document P1 included in the image data D1 captured by the imaging device 3 is referred to as subject resolution.

  FIG. 3 is a diagram showing three image data D1 having different subject resolutions. The three image data D1 shown in FIGS. 3A to 3C have the same image size (number of pixels in the vertical direction and the horizontal direction). In the image data D1 shown in FIG. 3A, the original image G1 of the specific original P1 is shown at a relatively small size in the center. In the image data D1 shown in FIG. 3A, the subject resolution of the specific document P1 is, for example, 400 dpi. In this case, one inch of the specific original P1 that is the subject is reflected in 400 pixels of the image data D1. On the other hand, in the image data D1 shown in FIG. 3B, the original image G1 of the specific original P1 is shown in a large size in almost the entire image size. The subject resolution of the specific document P1 in the image data D1 shown in FIG. 3B is higher than that of the image data D1 shown in FIG. 3A, for example, 1000 dpi. In this case, one inch of the specific document P1 that is the subject is reflected in 1000 pixels. Further, in the image data D1 shown in FIG. 3C, the original image G1 of the specific original P1 is shown in the smallest size as a part of the foreground subject. The subject resolution of the specific document P1 in the image data D1 shown in FIG. 3C is lower than the image data D1 in FIGS. 3A and 3B, for example, 50 dpi. In this case, one inch of the specific document P1 that is the subject is reflected in 50 pixels.

  If the subject resolution of the specific document P1 included in the image data D1 is found in this way, the feature pattern of the feature document is matched with the resolution of the sample image by performing resolution conversion on the image data D1. Detection processing can be performed. Therefore, the image processing apparatus calculates the subject resolution of the specific document P1 included in the image data D1, thereby eliminating the need to perform detection processing for detecting a feature pattern while performing resolution conversion many times. The detection process can be performed.

  If the subject resolution of the specific document P1 included in the image data D1 is known, it is possible to grasp how fine the specific document P1 included in the image data D1 is reflected as an image. Therefore, when the original image G1 of the specific original P1 included in the image data D1 is enlarged and printed, it is determined in advance whether or not the printed material has a quality that can be used as a counterfeit of the specific original P1. Is possible. Accordingly, the image processing apparatus 2 calculates the subject resolution of the specific document P1 included in the image data D1 and determines the subject resolution, so that the printed matter is specified even when the document image G1 of the specific document P1 is enlarged and printed. When a low-quality finish that cannot be used as a counterfeit of the document P1 is detected, the detection process for detecting the specific pattern from the image data D1 may not be performed, and the processing efficiency may be further improved. it can.

  The image processing apparatus 2 according to the present embodiment calculates the subject resolution based on attached information such as EXIF (Exchangeable Image File Format) added to the image data D1 captured by the imaging apparatus 3. Hereinafter, the image processing apparatus 2 will be described in more detail.

  FIG. 4 is a block diagram illustrating an example of a hardware configuration and a functional configuration of the image processing apparatus 2. In addition to the scanner unit 14 and printer unit 15 described above, the image processing device 2 is a non-volatile memory that includes a control unit 10 and a hard disk (HDD) that stores a program 46 and the like executed in the image processing device 2. Storage device 12, network interface 18, and card reader 20. The control unit 10 includes a CPU and a memory (not shown). The CPU reads and executes the program 46 stored in the storage device 12 to control the operation of each unit. The storage device 12 stores a control program 46 of the image processing device 2 and sample image information 47 of the characteristic pattern of the specific original P1.

  The network interface 18 is for connecting the image processing apparatus 2 to a network such as a LAN (Local Area Network). The image processing apparatus 2 can acquire the image data D1 via the network interface 18. The card reader 20 records data on a removable memory card or reads data from the memory card. The image processing apparatus 2 can also acquire the image data D1 from the card reader 20.

  When the CPU executes the program 46, the control unit 10 includes an image acquisition unit 30, an attached information reading unit 32, a resolution calculation unit 34, a determination unit 36, a detection unit 38, a print control unit 40, a print restriction unit 42, and a resolution. It functions as the conversion unit 44.

  The image acquisition unit 30 is a processing unit that acquires the image data D1. The image acquisition unit 30 can acquire the image data D1 from each of the network interface 18, the card reader 20, the scanner unit 14, and the storage device 12. For example, in the case of a scan job or a copy job, the image acquisition unit 30 acquires image data D1 from the scanner unit 14. In the case of a print job, the image acquisition unit 30 acquires image data D1 from any of the network interface 18, the card reader 20, and the storage device 12.

  The attached information reading unit 32 functions when the image acquisition unit 30 acquires the image data D1 from any one of the network interface 18, the card reader 20, and the storage device 12. Then, the attached information reading unit 32 determines whether attached information such as EXIF is added to the image data D1 obtained by the image obtaining unit 30. If the attached information is added to the image data D1, the attached information reading unit 32 reads the attached information.

  FIG. 5 is a diagram showing an example of the attached information 50 added to the image data D1. The attached information 50 is information in which a plurality of tags and a plurality of values corresponding to each of the plurality of tags are recorded, and information on various shooting parameters and image data D1 at the time of shooting by the imaging device 3 is recorded. Information. As shown in FIG. 5, the attached information 50 includes a subject distance 50a indicating the distance between the imaging device 3 and the subject at the time of photographing, a lens focal length 50b indicating the optical magnification of the photographing lens at the time of photographing, and a CCD. Information such as an X-direction resolution 50c indicating the X-direction resolution of the image sensor such as a sensor or a CMOS sensor, a Y-direction resolution 50d indicating the Y-direction resolution of the image sensor, and a resolution unit 50e indicating the resolution unit are included.

  When the attached information reading unit 32 reads the attached information 50 from the image data D1, the attached information 50 further relates to a subject distance 50a, a lens focal length 50b, an X direction resolution 50c, a Y direction resolution 50d, and a resolution unit 50e. Information is read out and the information is output to the resolution calculation unit 34.

  The resolution calculation unit 34 is a processing unit that calculates the subject resolution of the specific original P1 when the image data D1 is included in the original image G1 of the specific original P1. The resolution calculation unit 34 calculates the subject resolution of the specific document P1 based on the information output from the attached information reading unit 32.

More specifically, the resolution calculation unit 34 first calculates a shooting magnification indicating how much the subject was shot at the time of shooting by the imaging device 3 based on information output from the attached information reading unit 32. . That is, when the value of the subject distance 50a is L and the lens focal length 50b is F, the photographing magnification M is
M = F / (L−F) (Formula 1)
Can be calculated. Therefore, the resolution calculation unit 34 calculates the photographing magnification M by performing the calculation of Equation 1. With this photographing magnification M, it is possible to specify the size of a state in which a subject at a position separated from the imaging device 3 by a subject distance L is imaged on the imaging device.

Subsequently, the resolution calculation unit 34 calculates the subject resolution R of the specific document P1 based on the photographing magnification M. That is, if the value of the X direction resolution 50c is X, the subject resolution R is
R = X · M (Formula 2)
Can be calculated. Although the calculation formula using the X-direction resolution 50c is shown here, the Y-direction resolution 50d may be used. The resolution calculation unit 34 calculates the subject resolution R by performing the calculation of Expression 2. This subject resolution R is a value indicating how many pixels of the image sensor the one inch of the subject (specific document P1) photographed at a position separated from the image pickup apparatus 3 by the subject distance L is reflected. Then, the resolution calculation unit 34 outputs the subject resolution R calculated as described above to the determination unit 36.

  FIG. 6 is a diagram illustrating an example of the shooting magnification and the subject resolution calculated based on various shooting conditions. FIG. 6A is a diagram illustrating an example of calculating the photographing magnification, and FIG. 6B is a diagram illustrating an example of calculating the subject resolution. According to the example of FIG. 6A, under the same lens focal length, the shooting magnification decreases as the subject distance increases, and conversely, the shooting magnification increases as the subject distance decreases. In addition, the subject resolution decreases as the subject distance becomes longer and increases as the subject distance becomes shorter as shown in FIG. 6B under the same lens focal length. That is, the higher the shooting magnification, the higher the subject resolution, while the lower the shooting magnification, the lower the subject resolution. The lower the subject resolution, the rougher the original image G1 when the original image G1 of the specific original P1 is included in the image data D1.

  Returning to FIG. 4, the determination unit 36 is a processing unit that determines whether to perform a detection process of detecting a feature pattern from the image data D <b> 1 according to the subject resolution R of the subject calculated by the resolution calculation unit 34. . If the subject resolution R calculated by the resolution calculation unit 34 is lower than a preset limit value (threshold value), the determination unit 36 does not perform feature pattern detection processing on the image data D1. To decide. For example, if 50 dpi is set as the limit value in the subject resolution shown in FIG. 6B, the feature pattern detection process is not performed on the image data D1 of the subject resolution of the hatched portion R1 that is lower than the limit value. decide. That is, when the subject resolution R is lower than a predetermined limit value, even if the feature pattern based on the sample image information 47 and the image data D1 are matched, the subject image reflected in the image data D1 is too coarse. The pattern may not be detected. Even if the specific original P1 appears in the image data D1, if the original image G1 is enlarged and printed to the size of the actual specific original P1, a rough image is printed, so that it is used as a counterfeit of the specific original. It cannot be used, and damage caused by using as counterfeit banknotes or counterfeit securities does not occur. Therefore, when the subject resolution R is lower than the limit value, the determination unit 36 can improve the processing efficiency for the image data D1 by determining not to perform the feature pattern detection process.

  On the other hand, the determination unit 36 preferably determines that the feature pattern detection process is performed when the subject resolution R is higher than the limit value. This is because, when the subject resolution R of the image data D1 is greater than or equal to the limit value, it is possible to detect the feature pattern satisfactorily by performing the feature pattern detection process.

  However, even if the subject resolution R is higher than the limit value, the determination unit 36 obtains the image data D1 as a print job, and the subject resolution R is equal to or less than a predetermined value. It may be determined that the feature pattern detection process for the image data D1 is not performed. The predetermined value in this case is determined by the relationship with the print resolution when the printer unit 15 performs print output. If the original image G1 of the specific original P1 is included in the image data D1 and the subject resolution R of the specific original P1 is smaller than the print resolution, the original image G1 should be printed with the same size as the actual specific original P1. Then, it is necessary to perform enlarged printing. In this case, if the subject resolution R is 1/4 or less compared to the print resolution, the original image G1 is deteriorated by the enlarged printing, and thus a high-quality printed matter that can be used as a counterfeit of the specific original P1 is obtained. Absent. Therefore, when the subject resolution R is equal to or lower than a predetermined ratio (predetermined value) with respect to the print resolution, the determination unit 36 has a feature for the image data D1 even when the subject resolution is equal to or higher than the limit value. It may be determined that the pattern detection process is not performed. For example, when the print resolution is 600 dpi and the subject resolution R is 150 dpi or less, the feature pattern detection process may not be performed. In this case, as shown in FIG. 6B, the feature pattern detection process is not performed not only when the subject resolution R becomes the value of the shaded portion R1, but also when the subject resolution R becomes the value of the shaded portion R2. It becomes like this. Therefore, the processing efficiency can be further improved.

  In addition, when the image acquisition unit 30 sequentially acquires a plurality of pieces of image data D1, the determination unit 36 does not perform the above-described determination process when the detection process of the feature pattern by the detection unit 38 is not performed. The determination process as described above may be performed when the feature pattern detection process by the unit 38 is being performed. That is, for the first image data D1 first acquired by the image acquisition unit 30, it is determined that the feature pattern detection process is performed without performing the above-described determination process, and the feature for the first image data D1 is determined. When the second image data D1 is acquired by the image acquisition unit 30 when the pattern detection processing is not completed, the above-described determination processing is performed on the second image data D1. As a result, the feature pattern detection process can be performed on as much image data D1 as possible, and the second image acquired when the feature pattern detection process on the first image data D1 is being performed. If the subject resolution of the data D1 is less than the limit value or less than the predetermined value, there is an advantage that the subsequent processing can be promptly advanced without waiting for the second image data D1.

  When the determination unit 36 determines to perform the feature pattern detection process on the image data D1, the subject resolution R of the subject included in the image data D1 and the resolution (detection resolution) of the sample image included in the sample image information 47 are determined. Are compared, and it is determined whether or not there is a difference of a predetermined value or more in their resolutions. If it is determined that there is a difference of a predetermined value or more between the subject resolution R and the detection resolution of the sample image, the resolution conversion unit 44 is caused to function. Further, when the determination unit 36 determines that the subject resolution R and the detection resolution of the sample image are close to each other and there is no difference between the predetermined value and the resolution, the resolution conversion unit 44 is not operated. The detection unit 38 is caused to function.

  The resolution conversion unit 44 determines the subject resolution of the subject included in the image data D1 when the difference between the subject resolution R of the subject (specific document P1) included in the image data D1 and the detection resolution of the sample image is equal to or greater than a predetermined value. R is converted to the same resolution as the detection resolution. That is, the resolution conversion unit 44 matches the subject resolution R of the subject included in the image data D1 with the resolution of the sample image. Thus, when the feature pattern detection process is performed on the image data D1, the sample image can be matched with the same resolution as the subject resolution of the subject, so that the feature pattern can be detected with high accuracy. Then, the resolution conversion unit 44 outputs image data D1 in which the subject resolution R is matched with the resolution of the sample image to the detection unit 38.

  The detection unit 38 is a processing unit that executes a detection process for detecting a feature pattern based on the determination result by the determination unit 36. That is, the detection unit 38 executes the detection process when the determination unit 36 determines to perform the feature pattern detection process on the image data D1. When the conversion process of the subject resolution R is performed by the resolution conversion unit 44, the detection unit 38 performs a feature pattern detection process on the image data D1 subjected to the conversion process. On the other hand, when the conversion process by the resolution conversion unit 44 is not performed, the detection unit 38 performs a feature pattern detection process on the image data D1 acquired by the image acquisition unit 30.

  The detection unit 38 reads a sample image from the sample image information 47 stored in the storage device 12, performs matching processing between the sample image and the image data D1, and determines whether or not a feature pattern is included in the image data D1. To detect. At this time, if the image data D1 includes an image component having a relatively high correlation with the sample image, the detection unit 38 determines that the image component includes a feature pattern. As a result, when a feature pattern is detected from the image data D1, the detection unit 38 prohibits subsequent processing on the image data D1. For example, in the case of a print job, when a feature pattern is detected from the image data D1, the detection unit 38 causes the print restriction unit 42 to function. On the other hand, when no feature pattern is detected from the image data D1, the detection unit 38 permits subsequent processing to be performed on the image data D1. For example, in the case of a print job, if no feature pattern is detected from the image data D1, the detection unit 38 causes the print control unit 40 to function.

  The print control unit 40 functions when the image data D1 is acquired as a print job, and drives the printer unit 15 to perform print output. The print control unit 40 generates image data for printing based on the image data D1 acquired by the image acquisition unit 30, and drives the printer unit 15 based on the image data for printing, thereby responding to the image data D1. Print output. When the printing control unit 40 generates printing image data based on the image data D1, it reflects the printing settings designated by the user. Therefore, print image data obtained by enlarging or reducing the image data D1 acquired by the image acquisition unit 30 may be generated. In this case, the printer unit 15 performs enlarged printing or reduced printing. The print control unit 40 determines that the determination unit 36 does not perform the feature pattern detection process on the image data D1, or the detection unit 38 determines that the feature pattern is not included in the image data D1. In such a case, the printer unit 15 is driven to perform print output. The printer unit 15 forms an image with a predetermined print resolution on the print medium, and then outputs the print medium.

  The print restriction unit 42 is a processing unit that prohibits execution of printing by the print control unit 40 when a feature pattern is detected from the image data D1 by the detection unit 38. The print restriction unit 42 functions in conjunction with detection of a feature pattern from the image data D1 by the detection unit 38. For example, the print restriction unit 42 discards a print job corresponding to the image data D1 in which the feature pattern is detected. As a result, the print output based on the image data D1 including the characteristic pattern of the specific original P1 is not performed, so that the forgery of the specific original P1 can be prevented from being printed out. The print restriction unit 42 also deletes the image data D1 including the characteristic pattern of the specific original P1 as the print job is discarded.

  Next, a specific processing procedure performed in the image processing apparatus 2 will be described. 7 to 9 are flowcharts illustrating an example of a processing procedure performed in the image processing apparatus 2. This process is performed in the control unit 10 when the CPU of the control unit 10 executes the program 46. This process is started when a job is input to the image processing apparatus 2. As shown in FIG. 7, when this processing is started, the image processing apparatus 2 acquires image data D1 (step S1). The image data D1 may be acquired from any of the network interface 18, the card reader 20, the scanner unit 14, and the storage device 12. When acquiring the image data D1, the image processing apparatus 2 determines whether or not the attached information 50 is added to the image data D1 (step S2). As a result, when the attached information 50 is not added (NO in step S2), the image processing apparatus 2 sets the detection flag to ON (step S3). The detection flag is information indicating whether or not the feature pattern detection process is performed on the image data D1 acquired in step S1. When the detection flag is on, the feature pattern detection process is performed, and when the detection flag is off. The feature pattern detection process is not performed.

  On the other hand, when the attached information 50 is added to the image data D1 (YES in step S2), the image processing apparatus 2 reads the attached information 50 (step S4), and based on the information included in the attached information 50. The subject resolution R is calculated by performing the above-described calculations of Equations 1 and 2 (step S5). Then, the image processing device 2 executes subject resolution determination processing (step S6). In this subject resolution determination process, it is determined whether or not to perform the feature pattern detection process for the image data D1 based on the subject resolution R calculated in step S5, and the detection flag is set to ON or OFF. Details of the subject resolution determination process will be described later.

  Subsequently, the image processing apparatus 2 determines whether or not the detection flag is turned on (step S7). If the detection flag is on (YES in step S7), the image processing apparatus executes resolution conversion processing (step S8). In this resolution conversion processing, the detection resolution based on the sample image is set to one of the reading resolution and the printing resolution, and the subject resolution of the image data D1 or the resolution of the image data D1 is matched with the detection resolution as necessary. Resolution conversion is performed. Details of the resolution conversion process will be described later.

  After executing the resolution conversion process (step S8), the image processing apparatus 2 performs a feature pattern detection process (step S9). If the document image G1 of the specific document P1 is included in the image data D1, a feature pattern is detected from the document image G1 by this feature pattern detection process. Then, the image processing device 2 determines whether or not a feature pattern is detected from the image data D1 (step S10). When a feature pattern is detected from the image data D1 (YES in step S10), the image processing apparatus 2 immediately stops executing the job (step S11) and deletes the job (step S12). At this time, the image data D1 acquired in step S1 is also deleted.

  On the other hand, if the detection flag is off (NO in step S7), or if no feature pattern is detected in the feature pattern detection process (NO in step S10), the image processing apparatus 2 continues the job. Execution is permitted (step S13). At this time, if it is a print job, the image processing apparatus 2 permits print output based on the image data D1. As the job execution ends (YES in step S14), the image processing apparatus 2 ends this process.

  FIG. 8 is a flowchart illustrating an example of a detailed processing procedure of the subject resolution determination process (step S6). When starting this processing, the image processing apparatus 2 first reads a preset value X1 of the subject resolution (step S20). Then, the image processing apparatus 2 compares the subject resolution R calculated in step S5 with the limit value X1, and determines whether or not the subject resolution R is greater than or equal to the limit value X1 (step S21). As a result, when the subject resolution R is greater than or equal to the limit value X1 (YES in step S21), the image processing apparatus 2 further determines whether or not the image data D1 has been acquired as a print job (step S22). When the image data D1 is obtained as a print job (YES in step S22), the image processing apparatus 2 reads the print resolution X2 when the printer unit 15 performs print output. Then, the image processing apparatus 2 determines whether or not the subject resolution R is equal to or less than a predetermined ratio (predetermined value) with respect to the print resolution X2 (step S24). When the subject resolution R is equal to or lower than the predetermined ratio with respect to the print resolution X2 (YES in step S24), the image processing apparatus 2 turns off the detection flag (step S25). That is, in this case, even if the image data D1 includes the original image G1 of the specific original P1, if the original image G1 is enlarged and printed to the size of the actual specific original P1, the counterfeit of the specific original P1 is obtained. Therefore, since the image quality is deteriorated to the extent that it cannot be used, the detection flag is turned off and the feature pattern detection process (step S9) is not performed.

  On the other hand, when the image data D1 is not acquired as a print job (NO in step S22), or when the subject resolution R is not less than a predetermined ratio with respect to the print resolution X2 (NO in step S24). The image processing apparatus 2 turns on the detection flag (step S26). In this case, the feature pattern detection process (step S9) is performed.

  If the subject resolution R is less than the limit value X1 (NO in step S21), the image processing apparatus 2 further determines whether image data D1 has been acquired as a print job (step S27). If the image data D1 is not acquired as a print job (NO in step S27), the image processing apparatus 2 turns off the detection flag (step S28). Thereby, the feature pattern detection process (step S9) is not performed. On the other hand, if the image data D1 has been acquired as a print job (YES in step S27), has the image processing apparatus 2 performed feature pattern detection processing (step S9) for another image data D1? It is further determined whether or not (step S29). If a feature pattern detection process is being performed on another image data D1 (YES in step S29), the image processing apparatus 2 turns off the detection flag (step S30). If the feature pattern detection process for another image data D1 has not been performed (NO in step S29), the image processing apparatus 2 turns on the detection flag (step S31).

  Thus, the subject resolution determination process (step S6) is completed. In FIG. 8, when the subject resolution R is less than the limit value X1 (NO in step S21), it is determined whether or not the print job is a print job (step S27), and characteristics for other image data D1. The case where the process of determining whether or not the pattern detection process is performed (step S29) is performed to turn on or off the detection flag is illustrated, but the present invention is not limited to this. For example, if the subject resolution R is less than the limit value X1 (NO in step S21), the image processing apparatus 2 sets the detection flag to OFF without performing other conditions and performs feature pattern detection processing. You may not be broken.

  Next, FIG. 9 is a flowchart showing an example of a detailed processing procedure of the resolution conversion processing (step S8). When starting this process, the image processing apparatus 2 first determines whether or not the image data D1 acquired in step S1 is image data generated by the scanner unit 14 (step S40). As a result, when the image data D1 is generated by the scanner unit 14 (YES in step S40), the image processing apparatus 2 sets the detection resolution of the sample image to the reading resolution of the document by the scanner unit 14 (step S40). S41). If the image data D1 is not generated by the scanner unit 14 (NO in step S40), the image processing apparatus 2 sets the detection resolution based on the sample image to the print resolution when the printer unit 15 prints out (step S40). S42).

  Subsequently, the image processing apparatus 2 determines whether or not the subject resolution R has been calculated (step S43). If the subject resolution R has been calculated (YES in step S43), detection based on the subject resolution R and the sample image. A difference from the resolution is detected (step S44). Then, the image processing apparatus 2 determines whether or not the difference between the subject resolution R and the detection resolution based on the sample image is greater than or equal to a predetermined value (step S45). If there is a difference greater than or equal to the predetermined value (YES in step S45), the image processing apparatus 2 executes resolution conversion that matches the subject resolution R of the image data D1 with the detection resolution of the sample image (step S46). As a result, if the original image G1 of the specific original P1 is included in the image data D1, the resolution of the feature pattern of the original image G1 and the resolution of the feature pattern in the sample image will match each other. The feature pattern can be detected with high accuracy in the feature pattern detection process (step S9). In step S46, contrary to the above, resolution conversion for matching the detection resolution of the sample image with the subject resolution R of the image data D1 may be executed.

  On the other hand, when the difference between the subject resolution R and the detection resolution based on the sample image is not equal to or greater than the predetermined value (NO in step S45), the image processing apparatus 2 does not perform resolution conversion. That is, since the subject resolution R and the detection resolution based on the sample image are close to each other, the feature pattern can be detected well from the image data D1 without performing resolution conversion.

  If the subject resolution R has not been calculated (NO in step S43), the image processing apparatus 2 determines whether the image data D1 acquired in step S1 is image data generated by the scanner unit 14. (Step S47). As a result, when the image data D1 is generated by the scanner unit 14 (YES in step S47), the image processing apparatus 2 does not perform resolution conversion. That is, in this case, since the resolution of the image data D1 and the detection resolution match, there is no need for resolution conversion.

  On the other hand, when the image data D1 is not generated by the scanner unit 14 (NO in step S47), the image processing apparatus 2 determines whether or not print output based on the image data D1 is performed (step S48). ). As a result, when printing output based on the image data D1 is performed (YES in step S48), the image processing apparatus 2 executes resolution conversion that matches the resolution of the image data D1 with the printing resolution (step S49). As a result, the resolution of the image data D1 can be matched with the detection resolution of the sample image, so that the feature pattern can be detected well in the subsequent feature pattern detection process (step S9). In step S49, contrary to the above, resolution conversion that matches the detection resolution of the sample image with the resolution of the image data D1 may be executed.

  If the print output based on the image data D1 is not performed (NO in step S48), the image processing apparatus 2 does not perform resolution conversion. In this case, the subsequent feature pattern detection process (step S9) is executed on the image data D1 acquired in step S1 with the detection resolution of the sample image set to the print resolution. However, the present invention is not limited to this, and when print output based on the image data D1 is not performed (NO in step S48), for example, resolution conversion is performed so that the detection resolution of the sample image matches the resolution of the image data D1. Anyway.

  As described above, the image processing apparatus 2 according to the present embodiment calculates the subject resolution R of the subject included in the image data D1 based on the attached information 50 included in the image data D1 acquired by the image acquisition unit 30. In accordance with the subject resolution R, it is determined whether or not to perform detection processing for detecting a feature pattern from the image data D1. That is, when the subject resolution R is a relatively low value, even if the original image G1 of the specific original P1 is included in the image data D1, the original image can be obtained by performing print output based on such image data D1. Since the image quality degradation of G1 occurs, the specific original P1 cannot be forged. On the contrary, when the subject resolution R is a relatively high value, there is a possibility that the specific document P1 is forged if the image data D1 includes the document image G1 of the specific document P1. For this reason, the image processing apparatus 2 according to the present embodiment performs a feature pattern detection process on image data when the subject resolution R is a relatively high value, and performs image feature data detection on the image data when the subject resolution R is a relatively low value. The feature pattern detection process is not performed. As a result, the image processing apparatus 2 can efficiently execute the feature pattern detection process.

  Although one embodiment related to the present invention has been described above, the present invention is not limited to the contents described in the above embodiment, and various modifications can be applied.

  For example, in the above embodiment, the case where the image processing apparatus 2 is an MFP is illustrated as an example. However, the image processing apparatus 2 is not necessarily limited to the MFP. For example, the image processing apparatus 2 may be a printer having only a printing function, or may be a personal computer (PC).

  In the above embodiment, the case where a digital camera is used as an example of the imaging device 3 has been described. However, the imaging device 3 is not limited to a digital camera, and may be any device that can generate image data by photographing. Therefore, the imaging device 3 may be a device such as a smartphone, a tablet terminal, or a personal computer.

2 Image processing device 3 Digital camera (imaging device)
15 Printer section (printing means)
30 Image acquisition unit (acquisition means)
34 Resolution calculation unit (resolution calculation means)
36 determination unit (determination means)
38 Detection part (detection means)
40 Print Control Unit (Print Control Unit)
42 Print Restriction Unit (Print Restriction Unit)
44 Resolution converter (resolution converter)
50 Attached information

Claims (16)

Acquisition means for acquiring image data;
Resolution calculation means for calculating the subject resolution of the subject included in the image data based on the attached information included in the image data acquired by the acquisition means;
Detecting means for detecting a feature pattern of a specific document from the image data acquired by the acquiring means;
A determination unit that determines whether or not to cause the detection unit to perform the process of detecting the feature pattern from the image data according to the subject resolution calculated by the resolution calculation unit;
With
The image processing apparatus, wherein the detection unit performs a process of detecting the feature pattern based on a determination result by the determination unit. The determination unit can determine that the process of detecting the feature pattern is not performed when the subject resolution is less than a predetermined limit value,
The image processing apparatus according to claim 1, wherein the detection unit does not perform a process of detecting the feature pattern based on a determination result by the determination unit. Print control means for causing the printing means to print the image data obtained by the obtaining means based on a predetermined print resolution;
A print restriction unit that prohibits execution of printing by the print control unit when the feature pattern is detected from the image data by the detection unit;
The image processing apparatus according to claim 2, further comprising: The determination unit causes the detection unit to detect the feature pattern when the subject resolution is equal to or higher than the limit value and the subject resolution is equal to or lower than a predetermined value with respect to the print resolution. It is determined that
The image processing apparatus according to claim 3, wherein the detection unit does not perform a process of detecting the feature pattern based on a determination result by the determination unit.   The image processing apparatus according to claim 3, wherein the detection unit performs a process of detecting the feature pattern based on the print resolution. The determination means performs processing for detecting the feature pattern from the first image data by the detection means, and the subject calculated from second image data different from the first image data When the resolution is less than the limit value, determine that the process of detecting the feature pattern from the second image data is not performed,
The image processing according to claim 2, wherein the detection unit does not perform a process of detecting the feature pattern from the second image data based on a determination result by the determination unit. apparatus. The attached information includes subject distance information between the imaging device and the subject, lens focal length information of the imaging device, and resolution information of the imaging element in the imaging device,
The image processing apparatus according to claim 1, wherein the resolution calculation unit calculates the subject resolution using the subject distance information, the lens focal length information, and the resolution information. Resolution conversion means capable of converting the resolution of the image data acquired by the acquisition means;
Further comprising
The detection means performs a process of detecting the feature pattern from image data with a predetermined detection resolution,
The resolution conversion unit is configured to reduce the resolution of the image data so that the subject resolution becomes the same value as the detection resolution when the difference between the subject resolution calculated from the image data and the detection resolution is a predetermined value or more. Convert
The image processing apparatus according to claim 1, wherein the detection unit detects the feature pattern from the image data after the resolution is converted by the resolution conversion unit. A program executed in an image processing apparatus capable of acquiring and outputting image data,
The image processing apparatus;
Acquisition means for acquiring image data;
Resolution calculating means for calculating the subject resolution of the subject included in the image data based on the attached information included in the image data acquired by the acquiring means;
Detecting means for detecting a feature pattern of a specific document from the image data acquired by the acquiring means; and
A determination unit that determines whether to cause the detection unit to perform a process of detecting the feature pattern from the image data according to the subject resolution calculated by the resolution calculation unit;
Function as
The detection means performs a process of detecting the feature pattern based on a determination result by the determination means. The determination unit can determine that the process of detecting the feature pattern is not performed when the subject resolution is less than a predetermined limit value,
The program according to claim 9, wherein the detection unit does not perform a process of detecting the feature pattern based on a determination result by the determination unit. The image processing apparatus;
Print control means for causing the printing means to print the image data obtained by the obtaining means based on a predetermined print resolution; and
A printing restriction unit for prohibiting execution of printing by the printing control unit when the characteristic pattern is detected from the image data by the detection unit;
The program according to claim 10, further functioning as: The determination unit causes the detection unit to detect the feature pattern when the subject resolution is equal to or higher than the limit value and the subject resolution is equal to or lower than a predetermined value with respect to the print resolution. It is determined that
The program according to claim 11, wherein the detection unit does not perform a process of detecting the feature pattern based on a determination result by the determination unit.   The program according to claim 11 or 12, wherein the detection unit performs a process of detecting the feature pattern based on the print resolution. The determination means performs processing for detecting the feature pattern from the first image data by the detection means, and the subject calculated from second image data different from the first image data When the resolution is less than the limit value, determine that the process of detecting the feature pattern from the second image data is not performed,
The program according to any one of claims 10 to 13, wherein the detection unit does not perform a process of detecting the feature pattern from the second image data based on a determination result by the determination unit. The attached information includes subject distance information between the imaging device and the subject, lens focal length information of the imaging device, and resolution information of the imaging means included in the imaging device,
The program according to claim 9, wherein the resolution calculation unit calculates the subject resolution using the subject distance information, the lens focal length information, and the resolution information. The image processing apparatus;
Resolution conversion means capable of converting the resolution of the image data acquired by the acquisition means;
Further function as
The detection means performs a process of detecting the feature pattern from image data with a predetermined detection resolution,
The resolution conversion means converts the resolution of the image data so that the subject resolution becomes the same value as the detection resolution when the difference between the subject resolution and the detection resolution is a predetermined value or more.
16. The program according to claim 9, wherein the detection unit detects the feature pattern from the image data after the resolution is converted by the resolution conversion unit.

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