JP2012151586A - Image processing apparatus, image processing method, and image processing program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processing apparatus, an image processing method, and an image processing program capable of acquiring image data on a page-by-page basis from a medium, without setting the positions of folds by a user.SOLUTION: The image processing apparatus acquires an image from a front side 101 and a back side of a medium 100 formed of a sheet of foldable paper and determines an optical density thereof. The image processing apparatus extracts a portion in which the determined optical density is conspicuously different from that in the other part. If folds 121, 122, and 123 are formed in the medium 100 having a white ground color, the optical density in the portion becomes larger than the other portion. The image processing apparatus determines portions having larger optical densities as the positions of the folds and divides the image at the positions of the folds. As the result, images 111, 112, 113, and 114 divided on the page-by-page basis are produced.

Description

  The present invention relates to an image processing apparatus, an image processing method, and an image processing program that process an image based on a fold position.

  There is a medium made of a single sheet that can be folded, and information is attached to each of a plurality of pages separated by folds. Examples of this medium include folding brochures and restaurant menus. An apparatus capable of acquiring image data from such a medium in units of pages has been proposed. For example, in the apparatus described in Patent Document 1, the position of the fold is set in advance by the user as the page break position. The apparatus divides the original image data at the set delimiter positions. Accordingly, the apparatus can acquire image data in units of pages divided by folds.

JP 2008-258913 A

  In the above-described apparatus, the user needs to set the position of the fold. Therefore, there is a problem that the user has to repeatedly set the fold position when acquiring image data in units of pages from a plurality of media having different fold positions.

  An object of the present invention is to provide an image processing apparatus, an image processing method, and an image processing program capable of acquiring image data in units of pages from a medium without requiring the user to set a fold position.

  An image processing apparatus according to a first aspect of the present invention includes an acquisition unit that acquires a part of an image formed on a medium that is folded in a fold after being folded, and the image acquired in the acquisition unit A determination unit that determines an optical density of a part of the image, and when a difference between the optical density determined by the determination unit and an optical density of another part of the image is greater than a predetermined value, the part of the image is And a processing unit that processes the image based on the position of the fold when the first determination unit determines that a part of the image corresponds to the fold. ing.

  According to the first aspect, the image processing apparatus can specify the position of the fold of the medium based on the optical density of the image. Therefore, the image processing apparatus can recognize the specified fold position as a page break without requiring the user to set the fold position. The image processing apparatus can provide the user with an image divided for each page by accurately recognizing the page break and processing the image.

  In the first aspect, the acquisition unit is a first part that is a part of a first image formed on one side of the medium, and a part of a second image that is formed on the other side of the medium. A second part that is a part facing the first part across the medium is acquired, the determination unit determines the optical density of the first part and the second part, and the first determination unit determines the determination The difference between the optical density of the first part determined in the part and the optical density of the other part of the first image is greater than the predetermined value, and the optical density of the second part and the second image When the difference from the optical density of the other part is larger than the predetermined value, it may be determined that the first part and the second part correspond to the fold. The image processing apparatus determines the optical density when both the optical density determined from the image formed on one surface and the optical density determined from the image formed on the other surface satisfy a predetermined condition. Is equivalent to a crease. As a result, the image processing apparatus can accurately recognize page breaks. Therefore, a problem that occurs when the page breaks cannot be recognized correctly, for example, a problem that a part of the image at the adjacent position is included in the processed image or a part of the processed image is missing. Can be prevented.

  Further, in the first aspect, the first determination unit is configured such that the type of the fold is a mountain fold that is folded so that the first portion is outside, or a valley fold that is folded so that the first portion is inside. A difference between the optical density of the first part and the optical density of the other part of the first image is determined by the second determination unit for determining whether the optical density of the second part and the second part When the difference between the optical density of the other part of the image is larger than the difference between the optical density of the first part and the optical density of the other part of the first image, When the difference between the optical density of the second part and the optical density of the other part of the second image is smaller, a second determination unit that determines that the valley is folded, the processing unit, The image is added based on the fold type determined by the second determination unit. It may be. The image processing apparatus can specify the type of fold (mountain fold or valley fold). The image processing apparatus can specify the folded state and the opened state of the medium from the specified fold type. Therefore, the image processing apparatus can estimate the usage mode of the medium by the user from the folded or opened state of the medium, and can perform processing according to the usage mode.

  In the first aspect, the image processing apparatus further includes a storage unit that stores the type of the crease and pagination information that specifies a page number to be assigned to each of the images divided at the position of the crease, The section divides the image at the position of the fold, and divides the image based on the page allocation information stored in the storage unit in association with the fold type determined by the second determination unit. The page number may be set for each image. Therefore, the image processing apparatus can determine the optimum page allocation information according to the type of folds and the arrangement thereof, and can set the page number for each of the images divided at the page breaks.

  In the first aspect, the processing unit may divide the image at the position of the fold, and may set the divided images as individual files. Accordingly, the image processing apparatus can improve convenience when the user uses the processed image.

  In the first aspect, the image processing apparatus includes a first reading unit that reads the first image and a second reading unit that reads the second image, and the acquisition unit includes the first image read by the first reading unit. You may acquire said 2nd part of said 2nd image read in said 1st part and said 2nd reading part. As a result, the image processing apparatus can directly read images from both sides of the medium.

  Further, in the first aspect, a transport unit that transports the medium is provided, and the first reading unit and the second reading unit are respectively along a scanning direction orthogonal to the transport direction of the medium by the transport unit, The first image and the second image may be read. Thus, the image processing apparatus can directly read images from both sides of the medium while conveying the medium.

  In the first aspect, the acquisition unit acquires the first part corresponding to both ends of the first image in the scanning direction and the second part corresponding to both ends of the second image in the scanning direction. May be. As a result, the image processing apparatus can accurately identify a change in optical density. The reason is as follows. There is a high possibility that images such as characters and figures are included in the center of the image. Therefore, if these images greatly affect the optical density, the change in the optical density due to the formation of the crease becomes relatively small, and the accuracy in specifying the change in the optical density may deteriorate. On the other hand, the images at both ends are unlikely to contain characters and graphics. When the optical density is determined from the images at both ends, a change in the optical density due to the formation of the fold appears significantly. Therefore, the image processing apparatus can accurately identify a change in optical density.

  The image processing method according to the second aspect of the present invention includes an acquisition step of acquiring a part of an image formed on a medium that is folded in a crease and then being spread, and the image acquired in the acquisition step A determination step for determining an optical density of a part of the image, and when a difference between the optical density determined by the determination step and an optical density of another part of the image is greater than a predetermined value, And a processing step of processing the image based on the position of the fold when it is determined in the first determination step that a part of the image corresponds to the fold. ing.

  According to the second aspect, the position of the fold of the medium is specified based on the optical density of the image. Therefore, the specified fold position can be recognized as a page break without requiring the user to set the fold position. By accurately recognizing the page break and processing the image, it is possible to provide the user with an image separated for each page.

  An image processing program according to the third aspect of the present invention includes an acquisition step of acquiring a part of an image formed on a medium that is folded in a fold after being folded, and the image acquired in the acquisition step A determination step for determining an optical density of a part of the image, and when a difference between the optical density determined by the determination step and an optical density of another part of the image is greater than a predetermined value, And a processing step of processing the image based on the position of the fold when it is determined in the first determination step that a part of the image corresponds to the fold. To run.

  According to the third aspect, the position of the fold of the medium is specified based on the optical density of the image. Therefore, the specified fold position can be recognized as a page break without requiring the user to set the fold position. By accurately recognizing the page break and processing the image, it is possible to provide the user with an image separated for each page.

1 is a perspective view of an image processing device 1. FIG. 2 is a perspective view of the internal structure of the image processing apparatus 1 as viewed from the right side. FIG. 2 is a block diagram showing an electrical configuration of the image processing apparatus 1. FIG. 1 is a schematic diagram showing a medium 100. FIG. 4 is a graph showing optical density for each line, determined based on an image on the surface 101 side of the medium 100. FIG. 4 is a graph showing optical density for each line, determined based on an image on the back surface 102 side of the medium 100. It is a flowchart which shows a main process. It is a flowchart which shows a front-end | tip detection process. It is a flowchart which shows a fold detection process. FIG. 10 is a flowchart showing a fold detection process, which is a continuation of FIG. It is a flowchart which shows a crease discrimination | determination process. 1 is a schematic diagram showing a medium 100. FIG. It is a figure which shows the fold table 731. FIG. It is a figure showing a page allocation table 732.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. These drawings are used to explain technical features that can be adopted by the present invention. The configuration of the apparatus, the flowcharts of various processes, and the like that are described are not intended to be limited to only that, but are merely illustrative examples. The front side, back side, left side, right side, upper side, and lower side in FIG. 2 are the right side, left side, front side, rear side, upper side, and lower side of the image processing apparatus 1, respectively.

  A schematic configuration of the image processing apparatus 1 will be described with reference to FIGS. 1 and 2. The image processing apparatus 1 is a kind of image scanner. As shown in FIG. 1, the image processing apparatus 1 includes a main body 2, a paper feed tray 4, and a discharge tray 6. The main body 2 has a substantially triangular shape in a side view. A paper feed port 3 is provided in the upper part of the main body 2. A discharge port 5 is provided in the lower front portion of the main body 2. The paper feed tray 4 is connected to the rear side of the paper feed port 3 in the main body 2 and extends upward. The discharge tray 6 is connected to the lower side of the discharge port 5 in the main body 2 and extends forward. Sheets 7 set in the paper feed tray 4 are taken into the main body 2 one by one from the paper feed port 3. The taken sheet 7 is discharged from the discharge port 5 and stacked on the discharge tray 6. A start switch 15 and a lamp 16 are provided on the left side of the inclined surface on the front side of the main body 2. The user can start taking in the sheet 7 by operating the start switch 15. The lamp 16 notifies the user of the operation state of the image processing apparatus 1.

  As shown in FIG. 2, the main body 2 includes a conveyance path 11, a lower frame 12, and an upper frame 13. The sheet 7 taken in from the sheet feeding port 3 passes through the conveyance path 11 and is discharged from the discharge port 5. The lower frame 12 is provided below the conveyance path 11. The upper frame 13 is provided on the upper side of the conveyance path 11.

  The lower frame 12 includes conveyance rollers 17, 18, 19, and 20, a motor 56, a sheet sensor 37, and a line sensor 41. The transport roller 17 is provided in the vicinity of the paper feed port 3. Conveying rollers 18, 19, and 20 are provided on the downstream side of the conveying roller 17 in the conveying direction from the upstream side in the conveying direction toward the downstream side. The transport roller 17 takes the sheet 7 set on the paper feed tray 4 into the transport path 11. The conveyance rollers 18 and 19 convey the sheet 7 taken into the conveyance path 11 toward the discharge port 5. The conveyance roller 20 discharges the sheet 7 from the discharge port 5. The motor 56 drives the transport rollers 17, 18, 19, and 20.

  The sheet sensor 37 is provided on the downstream side of the conveyance roller 19 in the conveyance direction. The sheet sensor 37 includes a rotation unit 38. The upper end of the rotation unit 38 protrudes into the conveyance path 11. The rotation unit 38 is rotated downstream in the conveyance direction about the lower end by the sheet 7 passing through the conveyance path 11. The rotating unit 38 outputs an ON signal in a rotated state, and outputs an OFF signal in a non-rotated state. The sheet sensor 37 can detect whether or not the sheet 7 is above the line sensor 41 described later by receiving a signal output from the rotation unit 38.

  The line sensor 41 is provided on the downstream side of the sheet sensor 37 in the conveyance direction. The line sensor 41 is a contact-type image sensor (CIS: Contact Image Sensor). The length of the line sensor 41 in the left-right direction is substantially the same as the length of the transport path 11 in the left-right direction. The line sensor 41 can read the image of the lower surface of the sheet 7 conveyed along the conveyance path 11 line by line along a direction (scanning direction) orthogonal to the conveyance direction of the sheet 7.

  The line sensor 41 includes a light source, a lens, and a light receiving element. The light source irradiates the lower surface of the sheet 7 with light. The light receiving element collects the reflected light reflected on the sheet 7 by a lens, converts the light into RGB signals, and outputs the RGB signals. By performing image processing on the output RGB signals, an image of the lower surface of the sheet 7 is obtained in units of pages.

  The upper frame 13 includes separation members 21 and 25, pinch rollers 31 and 46, and a line sensor 42. The separating members 21 and 25 are high friction elastic members such as rubber. The separating member 21 is provided at a position facing the conveying roller 17. The separation member 25 is provided at a position facing the conveyance roller 18. Separating members 21 and 25 are provided to separate the lowermost sheet 7 from the other sheets among the plurality of sheets 7 set in the sheet feeding tray 4. The pinch roller 31 is provided at a position facing the conveying roller 19. The pinch roller 46 is provided at a position facing the conveying roller 20. The pinch rollers 31 and 46 rotate together with the conveyance rollers 19 and 20 and convey the sheet 7.

  The line sensor 42 is provided at a position facing the line sensor 41. The line sensor 42 is a CIS. The length of the line sensor 42 in the left-right direction is substantially the same as the length of the transport path 11 in the left-right direction. The configuration and drive mechanism of the line sensor 42 are the same as those of the line sensor 41 described above. The line sensor 42 can read the image on the upper surface of the sheet 7 conveyed along the conveyance path 11 line by line along a direction (scanning direction) orthogonal to the conveyance direction of the sheet 7.

  The electrical configuration of the image processing apparatus 1 will be described with reference to FIG. The image processing apparatus 1 includes a control circuit unit 61. The control circuit unit 61 is electrically connected to the start switch 15, the lamp 16, the motor drive circuit 63, the line sensor drive circuit 65, and the sheet sensor 37 via the input / output interface 62.

  The control circuit unit 61 includes a CPU 71, ROM 72, FLASH / ROM 73, RAM 74, and communication I / F 75. The CPU 71 is an arithmetic device that performs overall control of the image processing apparatus 1. The ROM 72 stores various parameters required when the CPU 71 performs processing. The FLASH / ROM 73 stores a program for the CPU 71 to perform processing and various tables to be described later. The RAM 74 temporarily stores various calculation results calculated by the CPU 71 and images read by the line sensors 41 and 42. The communication I / F 75 performs timing control when communicating with the PC 81 connected to the outside. The CPU 71 can receive a signal output from the sheet sensor 37 and indicating whether or not the sheet 7 is detected.

  The motor drive circuit 63 is connected to the motor 56. The motor driving circuit 63 drives and controls the motor 56 in accordance with an instruction from the CPU 71 of the control circuit unit 61. The line sensor drive circuit 65 is connected to the line sensors 41 and 42. The line sensor drive circuit 65 performs drive control for lighting the light sources of the line sensors 41 and 42 in accordance with instructions from the CPU 71 of the control circuit unit 61. Further, the line sensor driving circuit 65 converts the electrical signal of the light receiving element into an RGB signal or the like and outputs it. The CPU 71 can create an image based on the RGB signals received from the line sensor drive circuit 65 and temporarily store it in the RAM 74.

  With reference to FIG. 4, the medium 100 which is an example of the sheet 7 taken into the image processing apparatus 1 will be described. The front and back surfaces in FIG. 4 are defined as the front and back surfaces of the medium 100. The medium 100 has folds 121, 122, and 123 on the front surface 101, and folds 126, 127, and 128 on the back surface 102. The fold lines 121 and 126, the fold lines 122 and 127, and the fold lines 123 and 128 are opposed to each other with the medium 100 interposed therebetween. The medium 100 is a sheet-like medium that can be folded at the positions of the fold lines 121, 122, 123, 126, 127, and 128. Examples of the medium 100 include a folded pamphlet and a restaurant menu.

  At the positions of the fold lines 121, 123, 126, and 128, the fold lines 121 and 123 of the surface 101 are bent so as to be inside. At the positions of the fold lines 122 and 127, the fold line 122 of the surface 101 is bent so as to be on the outside. Hereinafter, the fold that is folded so that the fold on the surface 101 side is on the outside is referred to as “mountain fold”. The fold that is folded so that the fold of the surface 101 is on the inside is called “valley fold”. The surface 101 of the medium 100 is divided into four pages of images (images 111, 112, 113, and 114) by fold lines 121, 122, and 123. Similarly, the back surface 102 of the medium 100 is divided into four pages of images (images 115, 116, 117, and 118) by fold lines 126, 127, and 128. Information such as characters is posted on each page of the surface 101. Although not shown, it is assumed that information is similarly posted on each page of the back surface 102.

  The optical density at the position of the fold is greatly different from the optical density at the position without the fold. For example, when the ground color of the medium 100 is white, the optical density at the position of the fold is larger than the optical density at the position without the fold. The reason is that irregularities are formed on the surface of the medium 100 by the folds, and the irregularities cause irregular reflection. On the other hand, when the ground color of the medium 100 is a dark color, the optical density at the position of the fold is smaller than the optical density at the position without the fold. The reason is that the dark color on the surface is peeled off by the crease, and the original color (such as white) of the medium 100 is exposed. Note that since the fold extends from the end of the sheet to the opposite end, it is determined whether this is a fold or a line drawing formed on the surface of the medium 100 by using this feature. It becomes possible to do.

  5 and 6 show the optical density distribution of an image actually read from the medium 100. FIG. Note that the ground color of the medium 100 is white. FIG. 5 shows the optical density of the image on the front surface 101 of the medium 100, and FIG. 6 shows the optical density of the image on the back surface 102 of the medium 100. The horizontal axis indicates the position of the medium 100 in the horizontal direction (left-right direction in FIG. 4). The vertical axis represents the density level obtained by normalizing the optical density by 100.

  The positions of the optical density peaks 141, 142, and 143 in FIG. 5 correspond to the positions of the folds 121, 122, and 123 of the surface 101 of the medium 100, respectively. The positions of the optical density peaks 146, 147, and 148 in FIG. 6 correspond to the positions of the folds 126, 127, and 128 on the back surface 102 of the medium 100, respectively. The positions of the optical density peaks 144 and 145 in FIG. 5 and the positions of the optical density peaks 149 and 150 in FIG. 6 are the left end portion 124 (see FIG. 4) and the right end of the medium 100, respectively. This corresponds to the position of the portion 125 (see FIG. 4). Thus, when the ground color of the medium 100 is white, the optical density at the position of the fold is significantly higher than the optical density at other positions. On the other hand, when the ground color of the medium 100 is dark, the optical density at the fold position is significantly smaller than the optical density at other positions. Therefore, the position of the crease formed in the medium 100 can be specified by specifying the portion where the optical density has greatly changed.

  It is also possible to specify the type of fold based on the optical density. As shown in FIGS. 5 and 6, when the ground color of the medium 100 is white, the optical density of the front surface 101 is higher than that of the back surface 102 at the position of the fold folds (folds 122 and 127). (Peak 142> peak 147). On the other hand, at the positions of the valley folds (folds 121, 123, 126, and 128), the optical density is smaller on the front surface 101 than on the rear surface 102 (peak 141 <peak 146, peak 143 <peak 148). On the other hand, when the ground color of the medium 100 is a dark color, the optical density of the front surface 101 is smaller than that of the back surface 102 at the position of the mountain fold. On the other hand, the optical density of the front surface 101 is higher than that of the back surface 102 at the position of the valley fold. Therefore, by comparing the optical densities of the folds at positions facing each other across the medium 100, the fold type (mountain fold or valley fold) can be specified.

  The image processing apparatus 1 determines the optical density based on the image read from the medium 100 via the line sensors 41 and 42. The image processing apparatus 1 identifies the position of the fold by determining whether or not the optical density is significantly different from that of other portions. The image processing apparatus 1 divides an image read from the medium 100 at the specified fold position, and manages it for each page. Therefore, the user can use the divided image by dividing the image for each page without setting the position of the fold for the image processing apparatus 1. Note that “determining” refers to obtaining a specific numerical value based on the image data obtained via the line sensors 41 and 42, and specifying a specific value from a judgment criterion such as a table based on the obtained image data. Includes both determining numerical values.

  In addition, the image processing apparatus 1 identifies the type of the fold by comparing the optical densities of the front surface 101 and the back surface 102. The image processing apparatus 1 determines a page number to be assigned to each of the divided images based on the specified fold type. For example, the page number is determined as follows.

  For example, when the arrangement of fold types is “valley fold, mountain fold, valley fold” in order from the left as in the medium 100 of FIG. 4, the user starts from the image 111 of the leftmost page of the surface 101 with the image 111. It is assumed that browsing is performed in the order of 112, 113, and 114. Next, it is assumed that the user turns over the medium 100 and browses the medium 100 in the order of the images 117, 116, and 115 from the rightmost image 118 of the back surface 102. Therefore, the image processing apparatus 1 descends in the order of the images 111, 112, 113, 114, 118, 117, 116, and 115 when the arrangement of the fold types is “valley fold, mountain fold, valley fold”. Set the page number as follows. As described above, the image processing apparatus 1 can set an optimal page number on the basis of an assumed browsing order based on the arrangement order of the fold types.

  A main process executed in the CPU 71 of the image processing apparatus 1 will be described with reference to flowcharts of FIGS. When the CPU 71 is powered on, the main process is activated and executed. In order to detect a fold based on the two images read by the line sensors 41 and 42, two leading edge detection processes (see FIG. 8) corresponding to the two images and a fold detection process ( 9 and 10) are activated and executed in parallel.

  The main process will be described with reference to FIGS. As shown in FIG. 7, first, operating conditions are set via the PC 81 connected to the image processing apparatus 1 (S11). Examples of the operating conditions include the size type of the medium 100 (A4, B5, etc.), duplex / single-sided print setting, and the like. Note that these operating conditions may be automatically determined when the image processing apparatus 1 captures the medium 100.

  The user extends the fold line of the medium 100 so as to open the medium 100 and sets the medium 100 in the paper feed tray 4. FIG. 12 shows a state in which the medium 100 set on the paper feed tray 4 in a spread state is viewed from above. Assume that the surface 101 of the medium 100 faces upward. An arrow 160 in FIG. 12 indicates a direction in which the medium 100 is taken.

  It is monitored whether the start switch 15 is pressed (S13). If the start switch 15 is not pressed (S13: NO), the process returns to S13. When the start switch 15 is pressed (S13: YES), the driving of the motor 56 is started, and the transport rollers 17, 18, 19, and 20 start to rotate. The medium 100 set in the paper feed tray 4 is taken into the transport path 11 through the paper feed port 3, and the transport of the medium 100 is started (S15). The medium 100 taken in from the paper feed port 3 is transported in the transport path 11 from the paper feed port 3 toward the discharge port 5. Image reading by the line sensors 41 and 42 is started (S17). Thereafter, an image read by the line sensors 41 and 42 can be acquired. In S18 and S19, which are the next processes, the image of the surface 101 of the medium 100 is read line by line by the line sensor 42. The image on the back surface 102 of the medium 100 is read line by line by the line sensor 41.

  The leading edge detection process (see FIG. 8) of the medium 100 is executed (S18). Two fold detection processes (see FIGS. 9 and 10) corresponding to the image of the front surface 101 and the image of the back surface 102 of the medium 100 are started (S19). In the following, a tip detection process and a fold detection process based on an image read by the line sensor 42 will be described.

  The tip detection process will be described with reference to FIG. In the tip detection process, a variable H_STEP stored in the RAM 74 is used. The variable H_STEP is a variable indicating the operation state of the image processing apparatus 1. The variable H_STEP is initialized with 0 stored at the start of the tip detection process (S101).

  An image for one line read by the line sensor 42 is acquired (S102). Here, the acquired image is an image of the surface of the medium 100. By analyzing the acquired image, it is determined whether the medium 100 taken from the paper feed port 3 has reached the line sensor 42 (S103). For example, when a peak (for example, peak 144 in FIG. 5) is first detected in the optical density determined from the image for one line read by the line sensor 42, the detected peak is caused by the tip of the medium 100. You may judge that it is a peak. Then, it may be determined that the medium 100 has reached the line sensor 42. If the time has not elapsed since the start switch 15 was pressed and the medium 100 has not reached the line sensor 42 (S103: NO), the process returns to S102. An image for the next one line read by the line sensor 42 is acquired (S102), and the process is repeated.

  In the above description, it is determined whether or not the medium 100 has reached the line sensor 42 by analyzing the image read by the line sensor 42, but the present invention is not limited to this. For example, it may be determined whether the medium 100 has reached the line sensor 42 based on a signal output from the sheet sensor 37.

  When it is determined that the medium 100 has reached the line sensor 42 (S103: YES), the left and right end portions of the acquired image for one line are extracted (S104). The optical density of the extracted image is determined, and then the average value of the determined optical density is calculated (S105).

  In S104 and S105, for example, the optical density is determined from the image corresponding to the left end portion 131 and the right end portion 132 in the image for one line read from the medium 100 shown in FIG. 12, and the average value is calculated. Is done.

  It is determined whether or not the calculated average value of optical density is greater than a predetermined value (S106). The predetermined value is stored in advance in the ROM 72 as an approximate optical density threshold detected when the front end of the medium 100 is read. If it is determined that the calculated average value of the optical density is larger than the predetermined value (S106: YES), since the leading edge of the medium 100 is still being read, 1 is stored in the variable H_STEP (S107). The process returns to S102. On the other hand, if it is determined that the calculated average value of the optical density is equal to or less than the predetermined value (S106: NO), it is determined whether or not the variable H_STEP is 1 (S108). If it is determined that the variable H_STEP is not 1 (S108: NO), the process returns to S102. If it is determined that the variable H_STEP is 1 (S108: YES), after 0 is stored in the variable H_STEP (S109), all of the leading edge detection of the medium 100 is completed, so the leading edge detection process is terminated and the process is completed. Return to the main process (see FIG. 7).

  The crease detection process will be described with reference to FIG. In the fold detection process, a start flag, an error flag, a variable STEP, a position counter, and a width counter stored in the RAM 74 are used. The start flag is a flag for instructing the start of the crease determination process (see FIG. 11, described later). The error flag is a flag for notifying that an error has occurred in the crease determination process. The variable STEP is a variable indicating the operation state of the image processing apparatus 1. The position counter is a counter that specifies the position of an image for one line read by the line sensor 42. The width counter is a counter that specifies the width of a portion where the optical density changes significantly due to the formation of a fold. The start flag, error flag, variable STEP, position counter, and width counter are initialized by substituting 0 at the start of the fold detection process. The position counter is incremented by one each time an image for one line read by the line sensor 42 is acquired.

  1 is stored in the variable STEP (S35). Note that the state in which the variable STEP is 1 corresponds to a state in which the line sensor 42 is in any position in the sections 152, 154, 156, and 158 in FIG. Since the variable STEP has changed from 0 to 1 in S35, the position of the line sensor 42 has moved from the section 151 to the section 152 in FIG.

  Whether or not an error that cannot determine the type of the crease has occurred in the crease determination process (see FIG. 11) is determined based on the error flag (S37). If the fold type cannot be determined in the fold determination process, 1 is stored in the error flag (S97, see FIG. 11). If an error that cannot determine the fold occurs (S37: YES), the page number cannot be set for the image for each page. In this case, the process of detecting the fold is stopped, and only the image reading by the line sensor 42 is performed as follows.

  An image for the next one line read by the line sensor 42 is acquired (S39). It is determined whether the sheet sensor 37 detects the medium 100 (S41). When the sheet sensor 37 detects the medium 100 (S41: YES), the medium 100 exists below the line sensor 42. The process returns to S39, and an image for one line read by the line sensor 42 is repeatedly acquired (S39). On the other hand, when the sheet sensor 37 no longer detects the medium 100 (S41: NO), the medium 100 has already passed over the sheet sensor 37. In this case, 0 is stored in the variable STEP (S43). Since the variable STEP changes from 1 to 0, the position of the line sensor 42 has moved from the section 158 to the section 159 in FIG. Since all the reading of the image on the medium 100 is completed, the fold detection process is terminated, and the process returns to the main process (see FIG. 7).

  On the other hand, if the error flag is 0 and no error has occurred in the crease determination process (see FIG. 11) (S37: NO), the process proceeds to S45. An image for the next one line read by the line sensor 42 is acquired (S45). Of the acquired image for one line, the images of the left and right end portions are extracted (S47). The optical density of the extracted image is determined, and then the average value of the determined optical density is calculated (S49).

  In S47 and S49, for example, the optical density is determined from the image corresponding to the left end portion 131 and the right end portion 132 of the image for one line read from the medium 100 shown in FIG. 12, and the average value is calculated. Is done. The image of the central portion 133 is excluded from the target for determining the optical density. The reason is as follows. The central portion 133 of the image is likely to contain images such as characters and figures. Therefore, if these images greatly affect the optical density, the change in the optical density due to the formation of the crease becomes relatively small, and the accuracy in specifying the change in the optical density may deteriorate. On the other hand, the images of the left end portion 131 and the right end portion 132 are unlikely to contain characters and graphics. When the optical density is determined from the images of the left end portion 131 and the right end portion 132, the change in the optical density due to the formation of the fold appears significantly. Therefore, the change in optical density can be specified accurately.

  Next, an average value of the optical density is calculated based on the images at other positions excluding the image reading position for one line acquired at S45 (S50). Similar to the processing in S49, the images of the left and right end portions of the image are extracted, the optical density is determined, and the average value is calculated. Here, as for the images at other positions, for example, the variable STEP among all the images acquired from the start of the image reading by the line sensor 42 until the acquisition of the image for one line in S45. It is good also as an image acquired in the state which is 1. For example, in FIG. 12, when the line sensor 42 is in the section 155, the optical density may be determined based on the images acquired from the sections 152 and 154, and the average value may be calculated.

  As shown in FIG. 10, the difference between the average optical density calculated in S49 (see FIG. 9) and the average optical density calculated in S50 (see FIG. 9) is calculated (S51). It is determined whether or not the calculated difference is larger than a predetermined value (S52). When it is determined that the calculated difference is larger than the predetermined value (S52: YES), the average value of the optical density of the image for one line acquired in S45 (see FIG. 9) is the optical value of the image at another position. It is judged that it is significantly different from the average value of density. In this case, the position of the image for one line acquired in S45 may correspond to the position of the fold.

  It is determined whether the sheet sensor 37 detects the medium 100 (S53). When the sheet sensor 37 no longer detects the medium 100 (S53: NO), the medium 100 has already passed over the sheet sensor 37. The noticeable change in the average value of the detected optical density may be due to the edge of the medium 100. In this case, 0 is stored in the variable STEP (S43). Since the variable STEP changes from 1 to 0, the position of the line sensor 42 has moved from the section 158 to the section 159 in FIG. Since all the reading of the image on the medium 100 is completed, the fold detection process is terminated, and the process returns to the main process (see FIG. 7).

  On the other hand, when the sheet sensor 37 detects the medium 100 (S53: YES), the medium 100 exists below the line sensor 42. The optical density is accurately specified from the image on the medium 100. Therefore, it is determined that the significant change in the optical density calculated in S49 (see FIG. 9) corresponds to the peaks (for example, peaks 141, 142, and 143 in FIG. 5) caused by the folds formed on the medium 100. The 2 is stored in the variable STEP (S55). The state in which the variable STEP is 2 corresponds to a state in which the line sensor 42 is located at any position in the sections 153, 155, and 157 in FIG. In S55, since the variable STEP is changed from 1 to 2, the position of the line sensor 42 is moved from the section 152 to the section 153, from the section 154 to the section 155, and from the section 156 to the section 157 in FIG.

  The average value of the optical density calculated in S49 (see FIG. 9) is stored in the RAM 74 (S57). All the optical density average values repeatedly calculated in a state where the variable STEP is 2 are accumulated in the RAM 74. Note that the average value of the optical density stored in the RAM 74 in S57 is used when calculating the average value of the optical density in the section where the variable STEP is 2 in the crease determination process (S85, S87, see FIG. 11). (Details will be described later).

  It is determined whether or not the state in which the optical density has changed significantly determined in S52 is continuous twice or more (S59). In the case where no significant change is found in the previously determined average value of optical density (S59: NO), the position at this point is stored in order to store the time point when the average value of optical density starts to change significantly. The counter is stored in the RAM 74 (S61). The process returns to S37 (see FIG. 9). On the other hand, when the remarkable change in the optical density determined in S52 is continuous two or more times (S59: YES), the width of the portion where the optical density is significantly changed due to the formation of the fold is specified. Therefore, 1 is added to the width counter (S63). The process returns to S37. As shown in FIG. 9, an image of the next line read by the line sensor 42 is acquired (S45), and the process is repeated.

  On the other hand, in S52 of FIG. 10, the difference between the average value of the optical density calculated in S49 (see FIG. 9) and the average value of the optical density calculated in S50 (see FIG. 9) is not more than a predetermined value. Is determined (S52: NO), it is determined whether the variable STEP is 2 (S65). When the variable STEP is 2 (S65: YES), it is determined that the portion where the optical density is significantly changed due to the formation of the fold is completed. In this case, the exact position of the fold is specified (S67). The exact position of the fold is specified by calculating “position counter + width counter / 2” based on the position counter stored in the RAM 74 in S61 and the width counter updated in S63. The calculated value indicates the center position of each of the sections 153, 155, and 157 in which the variable STEP in FIG. The exact position of the identified fold is stored in the RAM 74.

  1 is stored in the variable STEP (S69). Since the variable STEP has changed from 2 to 1, the position of the line sensor 42 has moved from section 153 to section 154, section 155 to section 156, and section 157 to section 158 in FIG. In order to start the crease determination process (see FIG. 11) for determining the fold type, 1 is stored in the start flag (S71).

  The fold detection process described above is performed in the same manner on the image acquired from the line sensor 41, and the position of the fold is specified (S67, see FIG. 10). After the fold is specified, 1 is stored in the start flag (S71). The position of the fold is specified from both the front surface 101 and the back surface 102 of the medium 100. When 1 is stored in the start flag, a crease determination process is executed (S73). After the crease determination process is executed, the process returns to S37 (see FIG. 9).

  The crease determination process will be described with reference to FIG. In the crease determination process, it is monitored whether or not a corresponding crease is specified from both the front surface 101 and the back surface 102 of the medium 100. Whether or not 1 is stored in the start flag in the fold detection process based on the image acquired from the line sensor 42 (FIG. 9) and the fold detection process based on the image acquired from the line sensor 41 (FIG. 9). Then, it is determined whether or not a corresponding fold is detected (S81). If 1 is not stored in at least one of the start flags (S81: NO), the positions of the folds on the front surface 101 and the back surface 102 are not specified, and the process returns to S81.

  On the other hand, if 1 is stored in the start flag in both processes (S81: YES), does the position of the fold specified from the image on the front surface 101 match the position of the fold specified from the image on the back surface 102? Is determined (S83). Whether or not the positions of the folds match is determined by comparing the positions of the folds identified in S67 (see FIG. 10) of the fold detection process. If the fold positions do not match (S83: NO), at least one of the specified fold positions may be incorrect. In this case, the crease determination process ends, and the process returns to the crease detection process (see FIG. 10). On the other hand, when the position of the crease matches (S83: YES), it is determined that the crease is reliably formed at this position.

  Processing for determining the type of fold (mountain fold or valley fold) is performed as follows. Based on the average value of the optical density accumulated in the RAM 74 in S57 (see FIG. 10) of the fold detection process executed based on the image of the surface 101, the average value is calculated (S85). Based on the average value of the optical density accumulated in the RAM 74 in S57 of the fold detection process executed based on the image of the back surface 102, the average value is calculated (S87). The average value calculated in S85 and S87 corresponds to the average value of the optical density in the section where the variable STEP is 2 (see FIG. 4), that is, in the vicinity of the fold.

  The average value of the optical density near the fold of the front surface 101 calculated in S85 is compared with the average value of the optical density near the fold of the back surface 102 calculated in S87 (S89, S93). When the average value of the optical density in the vicinity of the fold line on the front surface 101 is larger than the average value of the optical density in the vicinity of the fold line on the back surface 102 (S89: YES), it is determined that the fold type is mountain fold (S91). The determination result is stored in the RAM 74 in association with the position of the fold. The process proceeds to S99.

  When the average value of the optical density in the vicinity of the fold line on the front surface 101 is smaller than the average value of the optical density in the vicinity of the fold line on the back surface 102 (S89: NO, S93: YES), the fold type is determined to be valley fold. (S95). The determination result is stored in the RAM 74 in association with the position of the fold. The process proceeds to S99.

  If the average value of the optical density in the vicinity of the fold line on the front surface 101 matches the average value of the optical density in the vicinity of the fold line on the back surface 102 (S93: NO), the type of the fold line cannot be determined. Is stored (S97). The process proceeds to S99. When 1 is stored in the error flag, the process of detecting the position of the fold is interrupted in S37 (see FIG. 9) of the fold detection process.

  In S99, 0 is stored in the start flag in order to initialize the start flag in which 1 is stored in the fold detection process corresponding to the front surface 101 and the fold detection process corresponding to the back surface 102 (S99). The fold determination process ends, and the process returns to the fold detection process (see FIG. 10).

  As described above, when both the optical density determined from the image formed on the front surface 101 and the optical density determined from the image formed on the back surface 102 satisfy the predetermined condition, the image processing apparatus 1 It can be determined that it corresponds to a crease. As a result, the image processing apparatus 1 can accurately recognize page breaks. The image processing apparatus 1 has a problem that occurs when a page break cannot be accurately recognized. For example, the processed image includes a part of an image at an adjacent position or a part of the processed image. It is possible to prevent occurrence of defects such as chipping.

  Further, the image processing apparatus 1 can identify the type of the fold by comparing the optical densities of the front surface 101 and the back surface 102 of the medium 100. The specified fold type is referred to when a page number is set for an image (described later).

  The crease determination process described above is executed every time a crease is detected in the crease detection process (see FIGS. 9 and 10). The determined fold types are stored in the RAM 74 by the number of folds.

  When all the folds are detected in the fold detection process (see FIGS. 9 and 10) and the reading of the image on the medium 100 is completed (S53: NO, S43, see FIG. 10), the fold detection process ends. To return to the main process (see FIG. 7). The type of each crease detected by the crease detection process is determined in the crease determination process (see FIG. 11). As shown in FIG. 7, after the fold detection process (S19) is completed, the images on the medium 100 read by the line sensors 41 and 42 are the positions of the folds detected by the fold detection process (S67). , See FIG. 10) (S21). For example, as shown in FIG. 12, the image on the surface 101 of the medium 100 is divided into images 111, 112, 113, and 114 by fold lines 121, 122, and 123.

  A page number is set for each of the images divided in S21 (S23). The page number to be set is determined as follows based on the crease table 731 and the page allocation table 732 stored in the FLASH / ROM 73.

  The crease table 731 will be described with reference to FIG. The fold table 731 stores a plurality of combinations of fold types (mountain folds or valley folds). The crease type for each crease position determined in the crease determination process (see FIG. 11) is applied to the crease table 731. And the index number when the arrangement | sequence of the kind of fold matches is specified. For example, in the medium 100 shown in FIG. 4, the creases are arranged in the order of “valley fold / mountain fold / valley fold” from the left. Therefore, when the crease table 731 is applied, the index number “2” that matches the arrangement of the crease types is specified.

  The page allocation table 732 will be described with reference to FIG. In the page allocation table 732, page number information (page allocation information) assigned to the images of the respective pages divided at the fold positions is stored for each index. After the index number is specified based on the fold table 731 (see FIG. 13), the page allocation information of the specified index number is selected from the page allocation table 732. The page number of each page specified by the selected page allocation information is set for each image divided at the position of the fold. The page allocation table 732 stores page allocation information determined on the assumption that the medium 100 is folded or opened. The image processing apparatus 1 can set page numbers in the browsing order when the medium 100 is actually browsed by the user.

  For example, in the medium shown in FIG. 4, since the index number “2” is specified based on the fold table 731 (see FIG. 13), the page allocation information corresponding to the index “2” in the page allocation table 732 is selected. . Based on the selected page allocation information, image 111 (leftmost-front) / page number 1, image 112 (left-front) / page number 2, image 113 (right-front) / page number 3, image 114 ( Rightmost-front) / page number 4, image 115 (leftmost-back) / page number 8, image 116 (left-back) / page number 7, image 117 (right-back) / page number 6, image 118 ( The page number is set for each image, such as (rightmost-back) / page number 5. The medium 100 sets page numbers so that images 111, 112, 113, 114, 118, 117, 116, and 115 are in descending order. Since it is assumed that the user browses the medium 100 in the order of the images 111, 112, 113, 114, 118, 117, 116, and 115, the set page number matches the browsing order of the pages by the user. To do. As described above, the image processing apparatus 1 can set an optimal page number on the basis of an assumed browsing order based on the arrangement order of the fold types.

  After the page number is set for each of the divided images in S23 of FIG. 7, the image reading by the line sensors 41 and 42 started in S17 is ended (S25). The driving of the motor 56 is finished, and the transport rollers 17, 18, 19, and 20 finish the rotation. The conveyance of the medium 100 is finished (S27). In order to notify the user that the medium loading 100 has been completed, the lamp blinks (S29). The main process ends.

  As described above, the image processing apparatus 1 can specify the position of the fold of the medium 100 based on the optical density of the image. Therefore, the image processing apparatus 1 can recognize the specified fold position as a page break without requiring the user to set the fold position. The image processing apparatus 1 can accurately recognize the page break and process the image on the medium 100 to provide the user with an image separated for each page.

  Further, the image processing apparatus 1 can determine optimum page allocation information according to the type of fold (mountain fold or valley fold), and can set a page number for each of the images divided at the page breaks.

  The CPU 71 that performs the process of S45 in FIG. 9 corresponds to the “acquisition unit” of the present invention, and the CPU 71 that performs the process of S49 corresponds to the “determination unit” of the present invention. S52 in FIG. 10 and the CPU 71 that performs the crease determination process in FIG. 11 correspond to the “first determination unit” of the present invention. The CPU 71 that performs the processes of S21 and S23 in FIG. 7 corresponds to the “processing unit” of the present invention. The CPU 71 that performs the processes of S89, S91, S93, and S95 in FIG. 11 corresponds to the “second determination unit” of the present invention. The FLASH ROM 73 that stores the page allocation table 732 corresponds to the “storage unit” of the present invention. The line sensors 41 and 42 in FIG. 2 correspond to the “reading unit” of the present invention. The process of S45 in FIG. 9 corresponds to the “acquisition step” of the present invention, and the process of S49 corresponds to the “determination step” of the present invention. S52 in FIG. 10 and the crease determination process in FIG. 11 correspond to the “first determination step” of the present invention. The processes of S21 and S23 in FIG. 7 correspond to the “machining step” of the present invention. The conveyance rollers 17, 18, 19, and 20 shown in FIG. 2 correspond to the “conveyance unit” of the present invention.

  The present invention is not limited to the above-described embodiment, and various modifications can be made. In the above-described embodiment, when the difference between the optical density at a predetermined position and the optical density at another position is larger than a predetermined value, the predetermined position is determined as a fold. This method is effective in that the position of the fold can always be determined by a fixed determination method regardless of the background color. On the other hand, the position of the fold may be determined based on the relationship between the optical density and a predetermined threshold value. When the ground color is white, a crease is determined when the optical density is greater than a predetermined threshold, and when the ground color is dark, a crease is detected when the optical density is less than the predetermined threshold. You may judge. This method is effective in that the position of the fold can be easily determined.

  Each image divided at the position of the fold may be managed as an individual file. Thereby, the image processing apparatus 1 can improve the convenience of the user who uses the processed image.

  In each process in the above-described embodiment, the image read by the image processing apparatus 1 is processed by the CPU 71 of the image processing apparatus 1 to determine the position and type of the fold. The present invention is not limited to this. Each process may be executed by the PC 81 connected to the image processing apparatus 1 via the communication I / F 75. That is, the PC 81 may acquire an image read from the sheet 7 by the image processing apparatus 1 and execute the above-described processes.

  In the above-described embodiment, a so-called sheet feed scanner that reads an image while conveying a medium has been described as an example of the image processing apparatus 1. However, the image processing apparatus 1 is not limited thereto, and may be, for example, a FAX or a multifunction peripheral. .

  In the above-described embodiment, the image processing apparatus 1 performs double-sided reading. However, the present invention is not limited to this. For example, the image processing apparatus may include one line sensor and perform single-sided reading.

1 Image Processing Device 37 Sheet Sensor 41 Line Sensor 42 Line Sensor 61 Control Circuit 71 CPU
72 ROM
73 FLASH ROM
732 page allocation table

Claims (10)

An acquisition unit that acquires a part of an image formed on a medium that has been folded in a crease and then in a spread state;
A determination unit that determines an optical density of a portion of the image acquired in the acquisition unit;
A first determination unit that determines that a part of the image corresponds to the fold when the difference between the optical density determined by the determination unit and the optical density of the other part of the image is greater than a predetermined value;
An image processing apparatus comprising: a processing unit configured to process the image based on a position of the fold when the first determination unit determines that a part of the image corresponds to the fold. The acquisition unit
A first part that is a part of the first image formed on one side of the medium, and a part of the second image that is formed on the other side of the medium, the part facing the first part across the medium Get the second part that is
The determination unit is
Determining the optical density of the first portion and the second portion;
The first determination unit is
The difference between the optical density of the first part determined by the determining unit and the optical density of the other part of the first image is greater than the predetermined value, and the optical density of the second part and the second part 2. The image processing apparatus according to claim 1, wherein when the difference from the optical density of another part of the image is larger than the predetermined value, the first part and the second part are determined to correspond to the fold. . The first determination unit is
The fold type is a second determination unit that determines whether the first fold is a mountain fold that folds so that the first portion is on the outside, or a valley fold that folds so that the first portion is on the inside, The difference between the optical density of the first part and the optical density of the other part of the first image is greater than the difference between the optical density of the second part and the optical density of the other part of the second image. The difference between the optical density of the first part and the optical density of the other part of the first image is the difference between the optical density of the second part and the second image. When the difference from the optical density of the other part is smaller, the second determination unit for determining that the valley fold is provided, the processing unit,
The image processing apparatus according to claim 2, wherein the image is processed based on the fold type determined by the second determination unit. A storage unit in which the type of folds and pagination information for specifying page numbers to be assigned to the images divided at the positions of the folds are stored in association with each other;
The processed portion is
The image is divided at the position of the fold, and the image of the divided image is divided based on the pagination information stored in the storage unit in association with the fold type determined by the second determination unit. The image processing apparatus according to claim 3, wherein the page number is set individually. The processed portion is
The image processing apparatus according to claim 1, wherein the image is divided at the position of the fold, and each of the divided images is an individual file. A first reading unit for reading the first image;
A second reading unit for reading the second image,
The acquisition unit
The first part of the first image read by the first reading unit and the second part of the second image read by the second reading unit are acquired. Image processing device. A transport unit for transporting the medium;
The first reading unit and the second reading unit read the first image and the second image, respectively, along a scanning direction orthogonal to a conveyance direction of the medium by the conveyance unit. The image processing apparatus according to claim 6. The acquisition unit
The first portion corresponding to both end portions in the scanning direction of the first image and the second portion corresponding to both end portions in the scanning direction of the second image are acquired. Image processing apparatus. An acquisition step of acquiring a portion of an image formed on a medium that has been folded in a crease and then in a spread state;
A determining step for determining an optical density of a portion of the image acquired in the acquiring step;
A first determination step of determining that a part of the image corresponds to the fold when the difference between the optical density determined by the determination step and the optical density of the other part of the image is greater than a predetermined value;
An image processing method comprising: a processing step of processing the image based on the position of the fold when it is determined in the first determination step that a part of the image corresponds to the fold. An acquisition step of acquiring a portion of an image formed on a medium that has been folded in a crease and then in a spread state;
A determining step for determining an optical density of a portion of the image acquired in the acquiring step;
A first determination step of determining that a part of the image corresponds to the fold when the difference between the optical density determined by the determination step and the optical density of the other part of the image is greater than a predetermined value;
An image processing program for causing a computer to execute a processing step of processing the image based on the position of the fold when it is determined in the first determination step that a part of the image corresponds to the fold.

Images