Image processing system and program

Abstract

To provide an image processing system which determines an image satisfying a certain condition in terms of the number and position of black dots on image data to be an image of a hole punched in an original, regardless of the presence or absence of a function for detecting an original size or a function for detecting the presence or absence of a hole on the basis of the original size, and detects the image data as image data of a blank original when there are no images such as characters, symbols, figures, etc. other than the image of the hole.SOLUTION: A processor determines whether the number derived by subtracting the sum of the number of black spots in one area, the number of black spots in another area corresponding to the one area, and the number of black spots in areas adjacent to the one area and the other area from the total number of black spots counted for each document is less than or equal to a specified value, and detects the image data of a document for which the derived number is less than or equal to the specified value as image data of a blank document.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to an image processing system and a program. [Background technology]

[0002] 2. Description of the Related Art In an image processing system, there is a technique for detecting image data of a blank document from image data of one or more scanned documents (hereinafter, referred to as a "blank document detection function").

[0003] In the blank page detection function, when a blank document has holes (for example, holes for binding the document), the system is required to recognize the holes as not being characters or figures, and to distinguish image data generated from the blank document from image data generated from documents other than blank documents. However, if the hole is round, for example, the hole is recognized as a black round image in the image processing system. Therefore, a separate function is required to distinguish whether the image is an image representing a hole or an image representing a black round figure formed on the document.

[0004] Patent Document 1 discloses an information processing device that can detect a document with punch holes as a blank page. This information processing device reads the document size in advance, extracts from the image data an image portion of an area where punch holes may exist based on the document size, and if there are pixels in that area that have a density equal to or higher than a predetermined value, recognizes the pixels as punch holes. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-150372 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, some image processing systems do not have a function for detecting the document size, and therefore cannot apply a technique for determining whether or not a document has holes based on the document size.

[0007] The object of the present invention is to determine that an image in which the number and position of black dots in image data satisfy certain conditions is an image of a hole punched in a document, regardless of the presence or absence of a function to detect the document size or a function to detect the presence or absence of a hole based on the document size, and to detect the image data as image data of a blank document if there are no images of letters, symbols, figures, etc. other than the image of the hole. [Means for solving the problem]

[0008] The invention of claim 1 is an image processing system comprising a processor, which determines whether image data generated by reading a received document has black dots, which are pixels with a specified density or higher, for each predetermined area, counts the number of the black dots for each of the predetermined areas, recognizes one of the predetermined areas where the number of black dots is equal to or greater than a first threshold as a first area, and recognizes an area that is located a predetermined length away from the first area and is located in a direction parallel to or perpendicular to the scanning direction of the image data and where the number of black dots is equal to or greater than the first threshold as an other area corresponding to the first area, calculates a sum of the numbers of the black dots for each of the documents, and determines whether the number derived by subtracting from the sum the sum of the number of black dots in the one area, the number of black dots in the other areas, and the number of black dots in areas adjacent to each of the one area and the other areas is equal to or less than a specified value, and detects the image data of a document where the derived number is equal to or less than the specified value as image data of a blank document.

[0009] The invention of claim 2 is the image processing system described in claim 1, characterized in that the processor stores the coordinates of the one area as first coordinates when at least one of the number of black dots in the one area and the number of black dots in the other area is greater than or equal to a second threshold, and detects the image data in which the first coordinates are stored as the image data of the blank document when the derived number is less than or equal to the specified value.

[0010] The invention of claim 3 is the image processing system according to claim 2, characterized in that the processor recognizes, in the image data in which the first coordinates are held, a region that is different from the one region and has the number of black dots equal to or greater than the first threshold as a different region, recognizes a region that is located a predetermined length away from the different region and is located in a direction parallel or perpendicular to the scanning direction of the image data and has the number of black dots equal to or greater than the first threshold as a further other region corresponding to the different region, and re-holds the coordinates of the different region as the first coordinates when at least one of the number of black dots in the different region and the number of black dots in the further other region is equal to or greater than the second threshold and a sum of the number of black dots in the different region and the number of black dots in the further other region is greater than a sum of the number of black dots in the one region and the number of black dots in the further other region.

[0011] The invention of claim 4 is the image processing system described in claim 1, characterized in that the size of the predetermined area is 1 / 2 the radius of the circle of the largest hole among the holes when the document has holes.

[0012] The invention of claim 5 is the image processing system according to claim 1, characterized in that the other area is one or more areas and is located at a position that is scanned after the one area.

[0013] The invention of claim 6 is the image processing system described in claim 3, characterized in that the further area is one or more areas and is located at a position that is scanned after the different area.

[0014] The invention of claim 7 is a program that causes a computer to determine whether image data generated by reading a received document has black dots, which are pixels with a density equal to or higher than a specified value, for each predetermined region, count the number of the black dots for each predetermined region, recognize one of the predetermined regions where the number of black dots is equal to or higher than a first threshold value as a first region, recognize an area that is located a predetermined length away from the first region and is located in a direction parallel to or perpendicular to the scanning direction of the image data and where the number of black dots is equal to or higher than the first threshold value as another region corresponding to the first region, calculate a sum of the numbers of the black dots for each document, and determine whether a number derived by subtracting from the sum the number of the black dots in the first region, the number of the black dots in the other regions, and the number of black dots in regions adjacent to each of the first region and the other regions is equal to or lower than a specified value, and detect the image data of a document where the derived number is equal to or lower than the specified value as image data of a blank document. Effect of the Invention

[0015] According to the inventions of claims 1 and 7, regardless of the presence or absence of a function to detect the size of a document or a function to detect the presence or absence of holes based on the size of a document, an image in which the number and position of black dots in the image data satisfy certain conditions can be determined to be an image of a hole punched in a document, and if there are no images of letters, symbols, figures, etc. other than the image of the hole, the image data can be detected as image data of a blank document.

[0016] According to the invention as set forth in claim 2, by providing a second threshold value in addition to a first threshold value as a condition for detecting certain image data as image data of a blank document, blank page detection can be achieved with higher accuracy.

[0017] According to the invention of claim 3, by extracting a certain area and its corresponding area that are the combination with the largest total number of black dots in one document, blank page detection can be achieved with higher accuracy.

[0018] According to the invention of claim 4, when determining whether or not a hole exists in a document, the occurrence of false detection can be suppressed even if the shape of the hole is other than round or if the hole is partially missing.

[0019] According to the invention of claim 5, the number of other areas is not limited to one, so the number of holes punched in the document is not limited to two, and blank page detection is also possible for documents with three or four holes, etc. Also, the processing speed is improved by setting the direction of the search for the other areas to be scanned after the first area.

[0020] According to the invention of claim 6, the number of further regions is not limited to 1, so the number of holes made in the document is not limited to 2, and blank page detection is also possible for documents with 3 or 4 holes, etc. Also, the processing speed is improved by setting the direction of the search for the further region to be scanned after the different region. [Brief description of the drawings]

[0021] [Figure 1] FIG. 2 is a block diagram showing a hardware configuration of the image processing system. [Diagram 2] FIG. 2 is a block diagram showing functions of the image processing system. [Diagram 3] FIG. 13 is a diagram showing an example of a blank document with holes punched by a two-hole punch. [Figure 4] 11A and 11B are diagrams illustrating an example of image data for explaining an outline of a blank paper detection process. [Diagram 5] 11A and 11B are diagrams illustrating an example of image data for explaining an outline of a blank paper detection process. [Figure 6] 11A and 11B are diagrams illustrating an example of image data for explaining an outline of a blank paper detection process. [Figure 7] 11A and 11B are diagrams illustrating an example of image data for explaining an outline of a blank paper detection process. [Figure 8] 11A and 11B are diagrams illustrating an example of image data for explaining an outline of a blank paper detection process. [Figure 9]11A and 11B are diagrams illustrating an example of image data for explaining an outline of a blank paper detection process. [Figure 10] 11A and 11B are diagrams illustrating an example of image data for explaining an outline of a blank paper detection process. [Figure 11] 4 is a flowchart showing a flow of processing in the image processing system according to the embodiment. [Figure 12] 12 is a flowchart of a process A shown in FIG. 11. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] FIG. 1 is a block diagram showing the hardware configuration of an image processing system. The image processing system 10 shown in FIG. 1 is a system having a technique (i.e., a blank paper detection function) of processing image data generated by reading a document and distinguishing image data generated from a blank document from image data generated from a document other than a blank document. Specifically, even if the read document has holes for binding the document (for example, two holes opened by a two-hole punch), the image processing system 10 does not uniformly recognize that the document has a black round figure or the like. Instead, the image processing system 10 judges whether the document is blank or not depending on whether the image portion representing the holes satisfies a predetermined condition. Note that the image processing system 10 distinguishes image data generated from a blank document from image data generated from a document other than a blank document by the above-mentioned judgment process, and can further execute other image processing using the result of the distinction. In the embodiment, an example will be described in which the image processing system 10 performs a process of excluding image data of a document determined to be blank from output data after the blank paper detection process. The processing after the blank page detection processing is not essential, and the image processing system 10 may perform the blank page detection processing and transmit the result as information to another system, etc., which may then perform the subsequent processing. Note that "output" here refers to processing for storing data in a memory or the like inside the image processing system 10, processing for transmitting data to the outside of the image processing system 10, processing for printing the scanned image on paper, etc., and is not particularly limited.

[0023] The image processing system 10 includes devices such as a personal computer (hereinafter referred to as "PC"), an image processing device, or a server. The image processing device is a device having at least one of a scanning function, a printing function, and a copying function. The image processing device may be a multifunction device having a scanning function, a printing function, a copying function, etc.

[0024] As shown in FIG. 1, the image processing system 10 also includes a UI 12, a communication device 14, a memory 16, and a processor 18.

[0025] The UI 12 is a user interface and includes a display and an input device. The display is a liquid crystal display or an EL display. The input device is a keyboard, a mouse, an input key, an operation panel, etc. The UI 12 may be a UI such as a touch panel that combines a display and an input device.

[0026] The communication device 14 includes one or more communication interfaces having a communication chip, a communication circuit, etc., and has a function of transmitting information to other devices and a function of receiving information from other devices. The communication device 14 may have a wireless communication function such as short-range wireless communication or Wi-Fi (registered trademark), or may have a wired communication function.

[0027] The memory 16 is a device that configures one or more storage areas for storing data. The memory 16 is, for example, a hard disk drive (HDD), a solid state drive (SSD), various types of memory (for example, RAM, DRAM, NVRAM, ROM, etc.), other storage devices (for example, optical disks, etc.), or a combination thereof.

[0028] The processor 18 controls the operation of each part of the image processing system 10 .

[0029] The processor 18 judges whether or not there are black dots, which are pixels with a density equal to or higher than a specified value, on the image data of the read document. The processor 18 judges whether or not a certain document is blank based on the total number of black dots for each document and the number of black dots in the image representing the two holes (hereinafter referred to as "punch holes") made in the document by a two-hole punch. Note that a "blank document" or a "blank document" is a document on which no images such as characters, symbols, or figures are formed. Here, it is desired that pixels consisting of only a very small number of black dots due to dust or small stains on the document are not included as elements of figures constituting the image. Therefore, the processor 18 judges whether or not the number of black dots on one image data is equal to or lower than a specified value. For example, if a blank document has only small stains, the number of black dots is equal to or lower than a specified value, so that the small stains are not recognized as an image and the document can be judged to be a blank document. Note that, although a two-hole punch is given as an example of a punch for making holes here, the present invention is not limited to this. For example, the "punch holes" may be three or four holes punched using a three-hole punch or a four-hole punch. Furthermore, in the embodiments, the shape of the punch holes is described as being round, but this is not limited thereto, and holes of shapes other than round are not excluded.

[0030] The image processing system 10 will be further described with reference to Fig. 2. Fig. 2 is a block diagram showing the functions of the image processing system.

[0031] The image processing system 10 includes a document reading unit 20, an image processing unit 22, a blank paper detection processing unit 24, an image output unit 26, and a storage medium / server 28. The functions of the document reading unit 20, the image processing unit 22, the blank paper detection processing unit 24, the image output unit 26, and the storage medium / server 28 are realized by a processor 18.

[0032] The document reading unit 20 detects and reads one or more documents, and generates image data from the read documents. For example, the document reading unit 20 detects and reads a document placed on a document table of the multifunction device or a document transported from a document tray. Also, for example, the document reading unit 20 may receive image data from an external information processing device or the like.

[0033] The image processing unit 22 performs image processing on the image data generated by the document reading unit 20 or the received image data. One example of the image processing is a process of dividing an area formed on the image data generated from an image of one page of a document into a plurality of areas (for example, areas represented by lattice-shaped blocks).

[0034] The blank page detection processor 24 is responsible for the main processing in blank page detection. Specifically, the blank page detection processor 24 includes a file size detection unit 30, a black dot count unit 32, and a punch hole determination unit 34. Through the processing performed by the file size detection unit 30, the black dot count unit 32, and the punch hole determination unit 34, the blank page detection processor 24 realizes blank page detection processing that causes the system to recognize even a document with punch holes as a blank page.

[0035] Next, a further description will be given of the file size detection unit 30, the black dot count unit 32, and the punch hole determination unit 34. The file size detection unit 30 detects the file size (in other words, the data volume) of the image data generated by the document reading unit 20 or the received image data.

[0036] Here, the reason why the file size detection unit 30 is provided in the image processing system 10 is that, depending on the detection result, subsequent processes related to the blank page detection process can be skipped and the process can proceed. In general, the file size of image data generated by reading a document that does not contain characters or figures is small. In other words, image data whose file size is less than a predetermined value can be determined to be image data generated from a blank document, and therefore no further blank page detection process needs to be performed. In such a case, the processor 18 ends the process for blank page detection. In this way, by detecting the file size of the image data in the file size detection unit 30, it is possible to roughly determine whether the scanned document is blank or not. As a result, for documents that are classified as blank at this stage, part of the subsequent blank page detection process can be omitted.

[0037] The black dot counting unit 32 counts the number of black dots on the image data. More specifically, the black dot counting unit 32 counts the number of black dots for each area (for example, an area represented by a lattice-shaped block shown in FIG. 4, which will be described later) divided by the processing of the image processing unit 22. Furthermore, the black dot counting unit 32 counts the number of black dots on one document in its entirety (i.e., the total number of black dots on one image data generated from an image of one page of a document).

[0038] Here, the reason why the black dot counting unit 32 counts the number of black dots in the entire document is that depending on the counting result, subsequent processes related to the blank page detection process can be skipped and the process can proceed. The black dot counting unit 32 adds up the number of black dots counted for each block for each image data generated from one document. Here, even if the blank page detection process for one image data is in progress, if the sum of the number of black dots reaches or exceeds a set value, the processor 18 ends the blank page detection process. That is, if the number of black dots in one image data reaches or exceeds a set value, it can be determined that the document on which the image data is based is clearly not a blank document based on the number of black dots, regardless of whether punch holes are present or not. Therefore, the blank page detection process is ended, and part of the subsequent blank page detection process for documents that are clearly not blank is omitted. Note that the above "set value" is a value larger than the "prescribed value" set as a threshold value for determining a blank document, since it is assumed that the number of black dots is clearly not blank.

[0039] The punch hole determination unit 34 determines whether the black dots in a certain area and its adjacent areas are black dots of an image representing a punch hole or black dots of an image representing a round black figure formed on the document, based on the number of black dots counted by the black dot count unit 32. The size of the adjacent areas is determined in advance, for example, based on the diameter of the punch hole.

[0040] The image output unit 26 excludes image data of documents that are determined to be blank documents based on the results of the series of processes performed in the blank page detection processing unit 24 from the output data and outputs the data.

[0041] The storage medium / server 28 is a storage medium that stores data output by the image output unit 26, or a device that accepts data output by the image output unit 26. Note that, when the image output unit 26 outputs image data to the outside of the image processing system 10, the storage medium / server 28 does not need to be provided.

[0042] Next, an overview of the blank page detection process performed by the image processing system 10 will be described with reference to Fig. 3 to Fig. 10. Fig. 3 is a diagram showing an example of a blank document with holes punched by a two-hole punch. Figs. 4 to 10 are diagrams showing an example of image data for explaining the overview of the blank page detection process.

[0043] 3 shows a document 40. The document 40 has holes 42a and 42b punched by a two-hole punch. The document 40 has no characters or figures except for the holes 42a and 42b, and is therefore a document that should be detected as a blank document under normal circumstances. In the following embodiment, blank document detection will be described using a blank document having punched holes as an example, as shown in FIG. 3.

[0044] FIG. 4 shows an image diagram of image data 44 generated by reading the document 40 shown in FIG. 3. The image data 44 is divided into regions of a predetermined size (more specifically, regions represented by grid-shaped blocks as shown by broken lines in FIG. 4). In addition, in FIG. 4, the upper left part of the image data 44 is surrounded by a two-dot chain line and the part is enlarged. A block 46 represented by diagonal lines in this enlarged diagram is an example of a region divided by a size predetermined by the processor 18. Hereinafter, the region divided by a predetermined size is referred to as a "predetermined region". In the embodiment, in a series of processes realized by the processor 18, the number of black dots is counted for each block represented by the block 46. Note that the "predetermined region" is not limited to the region represented by the grid-shaped blocks as described above. For example, each region may partially overlap with each other, and when the processing speed is important, each region to be processed may be spaced apart. In the embodiment, the size of the predetermined area is set to 1 / 2 the radius of the circle of the largest hole among the holes punched in the document, but it may be other than 1 / 2. The size of 1 / 2 the radius of the circle of the hole is set to suppress the occurrence of erroneous detection in the system. For example, the shape of the hole may be other than the normal shape made by a two-hole punch. Even if the normal shape of the punch hole is, for example, a circle or a square, the shape of the hole may be partially missing and may be a half moon shape or the like. In such a case, the block with the largest number of black dots is not necessarily the block located at the center of the hole. In this case, depending on the size of the set area, when searching for an image representing a punch hole in the blank page detection process, an area that is actually a part of the image of the punch hole may be excluded. When the shape of the punch hole is a circle, the block size that can minimize such excluded areas is 1 / 2 the radius of the circle of the punch hole. Therefore, in the image processing system disclosed in this specification, the size of the predetermined area is set to 1 / 2 the radius of the circle of the largest hole among the holes punched in the document.In addition, in FIG. 4, the black circular images 48a, 48b on the image data 44 are images representing the punch holes 42a, 42b, respectively (hereinafter referred to as "images 48a, 48b representing punch holes." The same expression will be used hereinafter in FIGS. 5 to 10.).

[0045] As shown by the three right-facing arrows in FIG. 4, the blank page detection process in the embodiment is executed sequentially from the upper left block to the right for each document. Specifically, in the blank page detection process in the embodiment, the top position on the leftmost side is set as the origin, and scanning is performed from there to the right. After scanning the right end, the scanning returns to the left end, and scanning is performed from a position one pixel or several pixels below to the right. This operation is repeated. That is, in the image processing system disclosed in this specification, the reading area of ​​the document is the maximum length of the document in the horizontal and vertical directions. Therefore, when performing the blank page detection process, the size of the document read in advance does not need to be recognized in the image processing system 10, and it is sufficient to proceed with the process sequentially until the maximum length of the document in the horizontal and vertical directions is reached. That is, the image processing system disclosed in this specification performs the process sequentially until the maximum length of the document in the horizontal and vertical directions is reached, thereby realizing blank page detection regardless of the presence or absence of a function to detect the document size and a function to detect the presence or absence of holes based on the document size.

[0046] FIG. 5 is a diagram for explaining an example in which, as a result of the blank page detection processor 24 carrying out the above process, a block that is a candidate for an image representing a punch hole is found.

[0047] When the number of black dots in a certain block (for example, block 48x shown by the dark black part in FIG. 7) is equal to or greater than the first threshold value, the blank page detection processing unit 24 obtains the number of black dots in another block (for example, block 48y shown by the dark black part in FIG. 7) corresponding to the certain block. The other block is a block located at a position away from the certain block by a predetermined length and located in a direction parallel or perpendicular to the scanning direction of the image data 44. More specifically, in the embodiment, the other block is a block located at a position scanned after the certain block in a direction parallel or perpendicular to the scanning direction of the image data 44. With this configuration, the accuracy of the processing is lower in the sense of reconfirmation compared to a case where processing is performed by returning to a block that has already been confirmed (i.e., scanned before the other block), but on the other hand, the overall processing speed is improved. As described above, in the blank page detection processing in the embodiment, the position of the topmost left side is set as the origin, and scanning is performed from there to the right, and after scanning the right end is completed, the operation of returning to the left end and scanning from a position one pixel or several pixels below to the right is repeated. Therefore, in FIG. 5, thick arrows pointing to the right and downward are displayed to indicate the direction of search for other blocks. Similarly, in the following embodiment, another block corresponding to a certain block will be described as being located to the right or downward of the certain block. Note that the "predetermined length" is set based on the distance between the two holes in the case of a two-hole punch, for example. The distance may be set based on the standard for two-hole punches defined by JIS, but is not limited thereto. Also, in the case of other multi-hole punches, the distance may be set based on the distance between the holes.

[0048] Next, the blank page detection processor 24 judges whether the number of black dots in the other blocks corresponding to a certain block is equal to or greater than a first threshold. If the number of black dots in the other blocks is equal to or greater than the first threshold, the blank page detection processor 24 further judges whether at least one of the number of black dots in the certain block and the number of black dots in the other blocks is equal to or greater than a second threshold. If all of the above conditions are met (i.e., the number of black dots in the certain block is equal to or greater than the first threshold, the number of black dots in the other blocks is equal to or greater than the first threshold, and at least one of the number of black dots in the certain block and the number of black dots in the other blocks is equal to or greater than a second threshold), the blank page detection processor 24 holds the coordinates of the certain block. Here, holding the coordinates of the block refers to, for example, storing the coordinates in the memory 16 as the first coordinates. The blank page detection processor 24 may also store information about the other blocks (i.e., information that the certain block is located to the right or below the certain block and at a position away from the certain block by a predetermined length) in the memory 16. The reason for providing two thresholds, the first threshold and the second threshold, is to achieve higher accuracy in blank page detection. First, the second threshold is set to a value larger than the first threshold. Then, the certain block and the other block determined to have a number of black dots equal to or greater than the first threshold are recognized by the system as candidates for punch holes, and a further determination process is performed using the second threshold, which is a value larger than the first threshold. This improves the accuracy of distinguishing between an image representing a punch hole and an image simply having black dots equal to or greater than the threshold. For example, there may be a case where the shape of one punch hole portion of a document is partially missing. In this case, the number of black dots in the block containing a part of the one punch hole may be less than the second threshold. However, if the number of black dots is insufficient simply because the shape of the punch hole is missing, and the image actually representing a punch hole is determined not to be an image representing a punch hole, this may lead to false detection in the blank page detection process. Therefore, the accuracy of blank page detection is improved by setting a condition that the number of black dots in at least one of the certain block and the other block must be equal to or greater than the second threshold.

[0049] Next, Fig. 6 is a diagram for explaining an example in which the coordinates of a certain block are not held, unlike Fig. 5. If the blank paper detection processor 24 proceeds with the above process and finds a block in the image data 44 that is a candidate for an image showing a punch hole (for example, block 48y, which is part of image 48b and is shown by a dark black portion in Fig. 7), the blank paper detection processor 24 searches for other blocks corresponding to that block. However, as shown in Fig. 6, a location to the right or below a certain block and a predetermined distance away is outside the range of the image data 44, so no block exists. In this case, the blank paper detection processor 24 ends the process for that certain block, and moves on to the process for the next block without holding the coordinates of the certain block.

[0050] Next, referring to FIG. 7, a process that is performed after the counting of the number of black dots for each block on the image data 44 is completed will be described. As described with reference to FIG. 5, the coordinates of the block 48x, which is a part of the image 48a representing the punch holes, are held in the image data 44. Also, information on the corresponding block 48y that exists at a position below the block 48x and a predetermined distance away from the block 48x is stored in the memory 16. In this case, the blank page detection processing unit 24 calculates the sum of the number of black dots in each of the blocks 48x and 48y and the number of black dots in the blocks adjacent to the blocks 48x and 48y. Then, the blank page detection processing unit 24 judges whether the number derived by subtracting the sum of the number of black dots in the blocks 48x, 48y, and the blocks adjacent to each of them from the sum of the number of black dots on the image data 44 is equal to or less than a specified value. Here, if the derived number is equal to or less than the specified value, the blank page detection processing unit 24 judges the document 40 on which the image data 44 is based to be blank.

[0051] In the embodiment, further image processing may be performed based on the results of the series of processes performed by the blank page detection processing unit 24. For example, a case will be taken as an example in which image data generated from a blank document and image data generated from documents other than the blank document are distinguished by the process performed by the blank page detection processing unit 24, and the information is stored in the memory 16. In this case, the image output unit 26 can exclude only the image data generated from the blank document from the image data based on the information stored in the memory 16, and output only the image data generated from documents other than the blank document. In other words, the image output unit 26 can exclude the image data 44 of the document 40 determined to be blank from the output data, and output the other image data. Then, the storage medium / server 28 stores the image data output by the image output unit 26. The series of processes performed by the image processing system 10 described above allows the user to further perform some image processing using the image data generated from documents other than the blank document stored in the storage medium / server 28.

[0052] Next, with reference to FIG. 8, another example in which the coordinates of a certain block are not held will be described. FIG. 8 is an image diagram in which a certain document 50, a black round figure 52a displayed on the document 50, and a figure showing image data 54 generated by reading the document 50 are displayed side by side. The image data 54 includes an image 56a showing the black round figure 52a. Here, it is assumed that the number of black dots in a certain block of the image 56a showing the black round figure is determined to be equal to or greater than the first threshold value by a series of processes performed by the blank paper detection processing unit 24. In this case, the blank paper detection processing unit 24 continues to search for other blocks corresponding to the certain block. In FIG. 8, the search is represented by thick arrows pointing to the right and downward. However, as shown in FIG. 8, no black dots are detected in a block located to the right or downward and at a predetermined distance from the certain block. In such a case, the blank paper detection processing unit 24 does not hold the coordinates of a certain block of the image 56a showing the black round figure. That is, the blank page detection processing unit 24 has determined that the image 56a representing the black round figure is not an image representing one of the holes made by the two-hole punch, but is merely a part of the black round figure 52a that has black points equal to or greater than the first threshold value. Therefore, the image data 54 generated from the document 50 is not detected as image data of a blank document, and the coordinates, which are a preprocessing step for the detection, are not stored.

[0053] Next, FIG. 9 is a diagram for explaining a case where coordinates are re-stored in the processing of one image data generated from one document. More specifically, FIG. 9 is an image diagram showing a document 60, four figures 62a, 62b, 64a, and 64b that are candidates for holes opened by a two-hole punch, and a figure showing image data 66 generated by reading the document 60, side by side. Here, an example is taken in which the length between figures 62a and 62b and the length between figures 64a and 64b match or nearly match the lengths of the two punches of a two-hole punch. In this case, if these four figures are holes opened by a two-hole punch, it is presumed that figures 62a and 62b are a pair, and figures 64a and 64b are a pair. Therefore, in FIG. 9, each pair of figures is surrounded and displayed by a two-dot chain line. In such a case where there are multiple punch hole candidates, the blank page detection processor 24 extracts a certain block and its corresponding block, which is a combination with the largest total number of black dots in one image data 66 generated from one document 60 (in other words, in an image showing holes made by a two-hole punch, a pair with the largest total number of black dots). Here, a case where the coordinates of a certain block in one image data 66 are already stored is taken as an example. In this case, the blank page detection processor 24 re-stores the coordinates of the different block when the total number of black dots in a block different from the certain block and the number of black dots in a further corresponding block is the largest. In the image data 66 in FIG. 9, the "different coordinates" are 68x indicated by the dark ink portion, and the "corresponding further different coordinates" are 68y indicated by the dark ink portion. 9, there are multiple candidates for punch holes (i.e., a pair of figures 62a and 62b and a pair of figures 64a and 64b), but the figures 64a and 64b are determined to be holes made by punching through the processing of the blank page detection processing unit 24. Note that, for ease of viewing, images representing the figures 62a and 62b are not shown in the image data 66 of FIG. 9 to show that the figures 62a and 62b are not holes as a result of the processing by the blank page detection processing unit 24 (more specifically, even if they are holes, they are not holes used in determining blank page detection).9, only images 68a and 68b representing holes 64a and 64b are displayed. As described above, by extracting the combination with the largest total number of black dots in one document, blank page detection can be achieved with higher accuracy.

[0054] FIG. 10 is a diagram for explaining blank page detection when holes are made by a three-hole punch instead of a two-hole punch. Specifically, FIG. 10 is an image diagram showing a document 70, holes 72a, 72b, and 72c made by a three-hole punch, and image data 74 generated by reading the document 70, side by side. On the image data 74, there are images 76a, 76b, and 76c representing the punch holes 72a, 72b, and 72c, respectively. The blank page detection process for a blank document in which holes are made by a three-hole punch is the same as the blank page detection process described above with reference to FIGS. 3 to 9. Specifically, when a certain block (for example, block 76x shown by a dark black portion in FIG. 10) having a number of black dots equal to or greater than the first threshold value is found, the blank page detection processing unit 24 searches for a block corresponding to the block 76x. In this case, in the process for finding holes punched by a three-hole punch, the number of corresponding blocks is preset to two, and a block located to the right or below a certain block 76x and a predetermined distance away is searched for. In FIG. 10, this corresponding block is block 76y shown in a dark black portion. Then, when block 76y is found, blank page detection processing unit 24 next searches for a block located to the right or below block 76y and a predetermined distance away. In FIG. 10, the block corresponding to block 76y is block 76z shown in a dark black portion. Next, blank page detection processing unit 24 judges whether the number of black dots in at least one of blocks 76x, 76y, and 76z is equal to or greater than a second threshold value. Then, if the number of black dots is equal to or greater than the second threshold value, blank page detection processing unit 24 judges whether the number derived by subtracting the total number of black dots in the blocks 76x, 76y, and 76z and the blocks adjacent to each of them from the total number of black dots on the image data 74 is equal to or less than a specified value. If the derived number is equal to or less than a specified value, the blank paper detection processor 24 determines that the document 70 on which the image data 74 is based is blank. As described above, the blank paper detection processor 24 applies a series of blank paper detection processes to holes punched by a multi-hole punch other than a two-hole punch.

[0055] Next, the process according to the embodiment will be further described with reference to Fig. 11. Fig. 11 is a flowchart showing the flow of the process of the image processing system according to the embodiment. In the embodiment, as described above, the processor 18 controls the operation of each unit of the image processing system 10 and performs the blank paper detection process.

[0056] First, the process is started when the user issues some kind of instruction for blank page detection via the UI 12. For example, the user places a document on the document tray of the multifunction device, and presses a button for scanning the document and a button such as "blank page detection ON". When the processor 18 receives the instruction, it executes a series of processes, such as detecting and reading one or more documents, and generating image data from the read documents. Next, the processor 18 detects the file size of the image data generated by reading the received document (S10). Here, unless it can be clearly determined from the file size that the document is blank, a process for determining whether the document is blank or not is required. Therefore, the processor 18 proceeds with the blank page detection process. Specifically, the processor 18 shifts the process to A in FIG. 11.

[0057] Next, the contents of the process A portion shown in FIG. 11 will be described with reference to FIG. 12. FIG. 12 is a flowchart of the process A shown in FIG. 11. The processor 18 proceeds with the process in the main scanning direction and determines the black dots in the target block (S30). Here, the target block is one block to be processed among blocks divided into a predetermined size in the image data generated in S10. Taking the image data 44 shown in FIG. 4 as an example, the target block immediately after the start of the process A is the upper left block 46. In addition, the "main scanning direction" is the direction toward the right in which the blank paper detection process is sequentially performed as shown by the three right-facing arrows in FIG. 4, and is synonymous with the horizontal direction or row direction in the embodiment. The processor 18 determines whether or not the target block has black dots, which are pixels with a density equal to or higher than a specified density (S30), and counts the number of black dots in the target block (S32).

[0058] Next, the processor 18 judges whether the number of black dots in the target block is equal to or greater than a first threshold (S34). If the number of black dots in the target block is equal to or greater than the first threshold (Yes in S34), the processor 18 judges whether at least one of the numbers of black dots in the target block and the other blocks corresponding thereto is equal to or greater than a second threshold (S36). As described above, the "other blocks" corresponding to the target block are blocks located at a position away from the target block by a predetermined length and located to the right or below the target block. In addition, in this flowchart, the explanation will be continued assuming that the number of black dots in the other blocks is equal to or greater than the first threshold. If the number of black dots is judged to be equal to or greater than the second threshold in S36 (Yes in S36), the processor 18 holds the coordinates of the target block, the direction of the other blocks corresponding to the target block, and the sum of the numbers of black dots in these blocks and adjacent blocks (S38). On the other hand, in either case of No in the judgment in S34 or No in the judgment in S36, the process proceeds to S40.

[0059] Next, processor 18 determines whether the target block is the final block in the main scan (S40), and if it is not the final block (No in S40), moves the processing target to the next block (S42). Processor 18 then executes the processes in S30 to S40 again. On the other hand, if the target block is the final block (Yes in S40), processor 18 ends process A and proceeds to S12 shown in FIG.

[0060] Next, processor 18 determines whether the target block is the last block row in the sub-scanning direction (S12). As described above, the "sub-scanning direction" is synonymous with the vertical or column direction, whereas the main scanning direction is synonymous with the horizontal or row direction. If the target block is not the last block row (No in S12), processor 18 moves the target of processing to the next sub-scanning block row (S14). In other words, the next target block is the block in the leftmost column of the next row. Then, processor 18 executes process A and the processing in S12 again. On the other hand, if the target block is the last block row in the sub-scanning direction (Yes in S12), the processing proceeds to S16. In other words, this is the case where the processing is sequentially performed until the maximum length of the document in the horizontal and vertical directions is reached, and the processing of the last block of the document is completed. In this case, following the above process, the processor 18 subtracts the total number of black dots in the block whose coordinates are held, the corresponding block of the block, and each of the adjacent blocks from the total number of black dots in the document, and judges whether the derived number is equal to or less than a specified value (S16). If it is determined in S16 that the derived number is equal to or less than the specified value (Yes in S16), the processor 18 judges that the target block and its corresponding block are punch holes (S18). That is, the processor 18 judges that the image data having the target block whose coordinates are held is image data generated from a document containing only "blank document + punch holes". On the other hand, if it is determined that the derived number is not equal to or less than the specified value (No in S16), the processor 18 judges that the target block and its corresponding block are not punch holes (S20). That is, the processor 18 judges that the document on which the image data having the target block whose coordinates are held is based is not a blank document. Through the above series of processes, even if the scanned document contains punch holes, processor 18 can determine whether the document is blank or not based on whether the image portion representing the hole satisfies a predetermined condition, without simply recognizing that the document contains a black round shape or the like.In addition, when there are multiple documents in the series of processes related to blank page detection described above, the series of processes may be performed after reading all of the documents, or the documents may be read one by one and the series of processes may be performed on one image data generated from one document each time.

[0061] In the image processing system 10, when reading a document, the inclination of the document may be detected. When the document is skewed, the size of a predetermined area (i.e., a divided block in the embodiment) is increased, so that punch holes can be detected even in image data generated from such a skewed document, and blank page detection processing can be realized.

[0062] The functions of the image processing system 10 described above are realized, for example, by cooperation between hardware and software. For example, the processor reads and executes a program stored in the memory of each device, thereby realizing the function of each device. The program is stored in the memory via a recording medium such as a CD or DVD, or via a communication path such as a network.

[0063] In the above embodiments, the term "processor" refers to a processor in a broad sense, and includes general-purpose processors (e.g., CPU: Central Processing Unit, etc.) and dedicated processors (e.g., GPU: Graphics Processing Unit, ASIC: Application Specific Integrated Circuit, FPGA: Field Programmable Gate Array, programmable logic device, etc.). The operations of the processor in each of the above embodiments may not only be performed by one processor, but may also be performed by multiple processors located at physically separate locations working together. The order of the operations of the processor is not limited to the orders described in each of the above embodiments, and may be changed as appropriate.

[0064] (Additional Note) (((1))) A processor is included. The processor, In the image data generated by reading the received document, it is determined whether or not there are black points, which are pixels having a density equal to or higher than a prescribed density, for each predetermined area; Counting the number of black dots for each of the predetermined regions; Identifying, as one region, one of the predetermined regions, in which the number of black dots is equal to or greater than a first threshold value; Recognizing, as another area corresponding to the one area, an area that is located at a predetermined distance from the one area and is located in a direction parallel or perpendicular to the scanning direction of the image data and in which the number of black dots is equal to or greater than the first threshold value; calculating a sum of the numbers of black dots for each document, and determining whether the number obtained by subtracting from the sum the sum of the number of black dots in the one region, the number of black dots in the other region, and the number of black dots in regions adjacent to the one region and the other region is equal to or smaller than a specified value; detecting the image data of the document in which the derived number is equal to or less than the specified value as image data of a blank document; 1. An image processing system comprising: (((2))) The processor, When at least one of the number of black dots in the one region and the number of black dots in the other region is equal to or greater than a second threshold, the coordinates of the one region are stored as first coordinates; When the derived number is equal to or smaller than the specified value, the image data in which the first coordinates are held is detected as the image data of the blank document. 2. The image processing system according to claim 1 , (((3))) The processor, In the image data in which the first coordinates are stored, A region different from the first region, in which the number of black dots is equal to or greater than the first threshold, is identified as the different region; identifying a region that is located at a position a predetermined length away from the different region and that is located in a direction parallel or perpendicular to the scanning direction of the image data, and in which the number of black dots is equal to or greater than the first threshold value, as a further region corresponding to the different region; when at least one of the number of black dots in the different region and the number of black dots in the further other region is equal to or greater than the second threshold value, and the sum of the number of black dots in the different region and the number of black dots in the further other region is greater than the sum of the number of black dots in the one region and the number of black dots in the further other region, re-holding the coordinates of the different region as the first coordinates. The image processing system according to (((2))) is characterized in that (((4))) the size of the predetermined area is, in the case where the document has holes, half the radius of the circle of the largest hole among the holes; 2. The image processing system according to claim 1 , (((5))) The other region is one or more regions, and is located at a position to be scanned after the one region. 2. The image processing system according to claim 1 , (((6))) The further other region is one or more regions, and is located at a position to be scanned after the different region. The image processing system according to (((3))) is characterized in that (((7))) On the computer, In the image data generated by reading the received document, it is determined whether or not there are black points, which are pixels having a density equal to or higher than a prescribed density, for each predetermined region; Counting the number of black dots for each of the predetermined regions; A region among the predetermined regions, the region having the number of black dots equal to or greater than a first threshold value, is identified as one region; a region that is located at a position separated by a predetermined length from the one region and that is located in a direction parallel or perpendicular to a scanning direction of the image data and in which the number of black dots is equal to or greater than the first threshold value is recognized as another region corresponding to the one region; calculating a total sum of the numbers of black dots for each document, and determining whether or not the number obtained by subtracting from the total sum the total of the numbers of black dots in the one region, the number of black dots in the other region, and the number of black dots in regions adjacent to the one region and the other region is equal to or smaller than a specified value; Detecting the image data of the document in which the derived number is equal to or less than the specified value as image data of a blank document. A program characterized by:

[0065] According to the image processing system relating to (((1))) and the program relating to (((7))), regardless of the presence or absence of a function for detecting the size of a document or a function for detecting the presence or absence of holes based on the size of the document, an image in which the number and position of black dots in the image data satisfy certain conditions can be determined to be an image of a hole punched in a document, and if there are no images of characters, symbols, figures, etc. other than the image of the hole, the image data can be detected as image data of a blank document. According to the image processing system of (((2))), by providing a second threshold value in addition to a first threshold value as a condition for detecting image data as image data of a blank document, blank page detection can be achieved with higher accuracy. According to the image processing system of (((3))), blank page detection can be achieved with higher accuracy by extracting a certain area and its corresponding area that is the combination that results in the largest total number of black dots in one document. According to the image processing system of (((4))), when determining whether or not a hole is present in a document, the occurrence of erroneous detection can be suppressed even when the shape of the hole is other than round or when the hole is partially missing. According to the image processing system of (((5))), the number of other areas is not limited to one, and therefore the number of holes punched in the document is not limited to two, and blank page detection is also possible for documents with three or four holes, etc. Also, the processing speed is improved by setting the direction of the search for the other areas to be scanned after the first area. According to the image processing system of (((6))), the number of further regions is not limited to one, and therefore the number of holes punched in the document is not limited to two, and blank page detection is also possible for documents with three or four holes, etc. Also, the processing speed is improved by setting the direction of the search for the further region to be scanned after the different region. [Explanation of symbols]

[0066] 10 image processing system, 12 UI, 14 communication device, 16 memory, 18 processor, 20 document reading unit, 22 image processing unit, 24 blank page detection processing unit, 26 image output unit, 28 storage medium / server, 30 file size detection unit, 32 black dot counting unit, 34 punch hole determination unit, 40 document, 42a, 42b punch holes, 44 image data, 46 blocks, 48a, 48b images representing punch holes, 48x, 48y blocks that are part of the images representing punch holes.

Claims

1. A processor is included. The processor, In the image data generated by reading the received document, it is determined whether or not there are black points, which are pixels having a density equal to or higher than a prescribed density, for each predetermined area; Counting the number of black dots for each of the predetermined regions; Identifying, as one region, one of the predetermined regions, in which the number of black dots is equal to or greater than a first threshold value; Recognizing, as another region corresponding to the one region, a region that is located at a predetermined distance from the one region and is located in a direction parallel or perpendicular to the scanning direction of the image data and in which the number of black dots is equal to or greater than the first threshold value; calculating a sum of the numbers of black dots for each document, and determining whether the number obtained by subtracting from the sum the sum of the number of black dots in the one region, the number of black dots in the other region, and the number of black dots in regions adjacent to the one region and the other region is equal to or smaller than a specified value; detecting the image data of the document in which the derived number is equal to or less than the specified value as image data of a blank document; 1. An image processing system comprising:

2. The processor, When at least one of the number of black dots in the one region and the number of black dots in the other region is equal to or greater than a second threshold, the coordinates of the one region are stored as first coordinates; If the derived number is equal to or smaller than the specified value, the image data in which the first coordinates are held is detected as the image data of the blank document.

2. The image processing system according to claim 1.

3. The processor, In the image data in which the first coordinates are stored, A region that is different from the first region and has the number of black dots equal to or greater than the first threshold is identified as the different region; identifying a region that is located at a position a predetermined length away from the different region and that is located in a direction parallel or perpendicular to the scanning direction of the image data, and in which the number of black dots is equal to or greater than the first threshold value, as a further region corresponding to the different region; when at least one of the number of black dots in the different region and the number of black dots in the further other region is equal to or greater than the second threshold value, and the sum of the number of black dots in the different region and the number of black dots in the further other region is greater than the sum of the number of black dots in the one region and the number of black dots in the further other region, re-holding the coordinates of the different region as the first coordinates.

3. The image processing system according to claim 2.

4. the size of the predetermined area is, in the case where the document has holes, half the radius of the circle of the largest hole among the holes; 2. The image processing system according to claim 1.

5. The other region is one or more regions, and is located at a position to be scanned after the one region.

2. The image processing system according to claim 1.

6. The further other region is one or more regions, and is located at a position to be scanned after the different region.

4. The image processing system according to claim 3.

7. On the computer, In the image data generated by reading the received document, it is determined whether or not there are black points, which are pixels having a predetermined density or higher, for each predetermined area; Counting the number of black dots for each of the predetermined regions; A region among the predetermined regions, the region having the number of black dots equal to or greater than a first threshold, is recognized as one region; a region that is located at a position separated by a predetermined length from the one region and that is located in a direction parallel or perpendicular to a scanning direction of the image data and in which the number of black dots is equal to or greater than the first threshold value is recognized as another region corresponding to the one region; calculating a total sum of the numbers of black dots for each document, and determining whether or not the number obtained by subtracting from the total sum the total of the numbers of black dots in the one region, the number of black dots in the other region, and the number of black dots in regions adjacent to the one region and the other region is equal to or smaller than a specified value; Detecting the image data of the document in which the derived number is equal to or less than the specified value as image data of a blank document. A program characterized by:

Images