Image processing apparatus, and image processing method

Abstract

To automatically adjust the ratio of expansion and contraction of a read image even if the size of an original document is unknown, thereby improving convenience.SOLUTION: An image processing apparatus comprises a control unit that can execute character recognition processing on a read image of a document, and a storage unit that stores a reference aspect ratio of a reference character. The control unit can execute extraction processing of extracting one or more characters from the read image through the character recognition processing, execute acquisition processing of acquiring the aspect ratio of an image area of a representative character corresponding to the reference character, of the one or more characters, on the basis of the read image, and execute adjustment processing of adjusting the ratio of expansion and contraction of the read image so that the aspect ratio of the image area becomes closer to the reference aspect ratio.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an image processing apparatus and an image processing method that can adjust an image read from a document. [Background technology]

[0002] In image reading devices that read documents using an ADF (automatic document feeder), the read image can become stretched or shrunk due to temperature, temperature changes, and other factors, as well as changes in the feed section over time, such as roller wear. Patent Document 1 discloses an image reading device that corrects the sub-scanning magnification. This image reading device corrects the sub-scanning magnification by receiving input such as the "sub-scanning length of the scanned document" and comparing it with the "sub-scanning length of the scanned image." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-119565 Summary of the Invention [Problem to be solved by the invention]

[0004] The image reading device described above corrects the sub-scanning magnification assuming that the size of the original document is known. Therefore, if the size of the original document is unknown, the sub-scanning magnification cannot be corrected. As such, there is still room for improvement in adjusting the expansion / contraction ratio of the read image. The above-mentioned problem may also occur in flatbed type image reading devices that read an original on a flatbed document table while moving the reading unit. [Means for solving the problem]

[0005] The image processing device of the present invention comprises: a control unit capable of executing character recognition processing on a scanned image of a document; a storage unit that stores a reference aspect ratio for a reference character; The control unit performing an extraction process to extract one or more characters from the read image by the character recognition process; performing an acquisition process for acquiring an aspect ratio of an image area of a representative character corresponding to the reference character among the one or more characters based on the scanned image; The present invention has an aspect in which an adjustment process can be executed to adjust the expansion / contraction ratio of the read image so that the aspect ratio of the image area approaches the reference aspect ratio.

[0006] Further, the image processing method of the present invention comprises: an extraction step of extracting one or more characters from the read image of the document by performing character recognition processing on the read image; an acquisition step of acquiring, based on the scanned image, an aspect ratio of an image area of a representative character corresponding to a reference character associated with a reference aspect ratio among the one or more characters; and adjusting the expansion / contraction ratio of the read image so that the aspect ratio of the image area approaches the reference aspect ratio. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a block diagram schematically illustrating an example of the configuration of an image processing apparatus. [Figure 2] FIG. 1 is a diagram schematically illustrating an example of the structure of a scanner. [Figure 3] FIG. 4 is a diagram schematically illustrating an example of the structure of a reference character table. [Figure 4] 10A and 10B are diagrams illustrating an example of adjusting the expansion / contraction ratio of a read image. [Figure 5] FIG. 4 is a diagram schematically showing an example of a page of a read image. [Figure 6] 10 is a flowchart schematically illustrating an example of a read image generation process. [Figure 7] FIG. 10 is a diagram schematically showing an example of dividing a read image into regions. [Figure 8] FIG. 10 is a diagram schematically showing an example of a reading result between documents. [Figure 9]10A and 10B are diagrams illustrating an example of adjusting the expansion / contraction ratios of an acceleration region, a constant speed region, and a deceleration region in a scanned image. [Figure 10] 10 is a flowchart illustrating an example of a manual adjustment process. DETAILED DESCRIPTION OF THE INVENTION

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes embodiments of the present invention. Of course, the following embodiments are merely examples of the present invention, and not all of the features shown in the embodiments are necessarily essential to the solution of the invention.

[0009] (1) Summary of the aspects included in the present invention: First, an overview of the embodiments included in the present invention will be described with reference to the examples shown in Figures 1 to 10. Note that the figures in this application are diagrams showing schematic examples, and the magnifications in each direction shown in these figures may differ, and the figures may not be consistent with each other. Of course, each element of this embodiment is not limited to the specific example indicated by the symbol. In the "Outline of the embodiments included in the present invention," the words in parentheses indicate supplementary explanations for the immediately preceding words. In addition, in the present application, a numerical range "Min to Max" means a value equal to or greater than the minimum value Min and equal to or less than the maximum value Max.

[0010] [Aspect 1] As illustrated in FIG. 1, an image processing device U0 according to one embodiment includes a control unit 40 capable of performing character recognition processing (e.g., OCR) on a scanned image IM0 of a document D0, and a storage unit 60 that stores a reference aspect ratio RC0 for a reference character 200. As illustrated in FIG. 6, the control unit 40 performs an extraction process to extract one or more characters 300 from the scanned image IM0 through the character recognition process. As illustrated in FIGS. 3 to 6, the control unit 40 performs an acquisition process to acquire, based on the scanned image IM0, an aspect ratio RC1 of an image area 350 of a representative character 310 corresponding to the reference character 200 among the one or more characters 300. The control unit 40 can execute an adjustment process to adjust the expansion / contraction ratio of the scanned image IM0 so that the aspect ratio RC1 of the image area 350 approaches the reference aspect ratio RC0.

[0011] Since the reference aspect ratio RC0 of the reference character 200 is known, the aspect ratio RC1 of the image area 350 of the representative character 310 approaches the reference aspect ratio RC0, and the scanned image IM0 is adjusted to reduce stretching and shrinkage. In this way, the expansion / contraction ratio of the scanned image IM0 is automatically adjusted even if the size of the original document D0 is unknown, and therefore the above embodiment can improve convenience.

[0012] There are various examples of the above-described aspects. The aspect ratio may be the ratio of the vertical length to the horizontal length, or the ratio of the horizontal length to the vertical length. Examples of reference characters include characters in fonts with common aspect ratios. The expansion / contraction ratio of the read image may be adjusted each time a document is read on a job basis, or may be adjusted at predetermined intervals such as once a day, or may be adjusted when an adjustment is instructed in manual adjustment mode. Of course, the above remarks also apply to the following aspects.

[0013] [Aspect 2] 1, the image processing device U0 may further include a reading unit 30 that reads the document D0 and generates the read image IM0 that has been adjusted with the set expansion / contraction ratio RR0. As shown in FIG. 6, in the adjustment process, the control unit 40 may determine the expansion / contraction ratio RR1 so that the aspect ratio RC1 of the image area 350 approaches the reference aspect ratio RC0, and apply the determined expansion / contraction ratio RR1 as the new set expansion / contraction ratio RR0. In the above case, the read image IM0 with the determined expansion / contraction ratio RR1 is generated by the reading unit 30, which can provide a suitable example for improving convenience.

[0014] [Aspect 3] As illustrated in Figures 6 and 8, in the adjustment process, the control unit 40 may determine the expansion / contraction ratio RR1 so that the aspect ratio RC1 of the image area 350 approaches the reference aspect ratio RC0 within a range that does not become the reference aspect ratio RC0, and may apply the expansion / contraction ratio RR1 as the set expansion / contraction ratio RR0. In the above case, even if the expansion / contraction ratio of the scanned image changes between documents, the change in expansion / contraction of the characters can be made inconspicuous.

[0015] [Aspect 4] 6, in the extraction process, the control unit 40 may extract a plurality of characters 300 from the scanned image IM0 through the character recognition process. In the acquisition process, the control unit 40 may extract a plurality of representative characters 310 from the plurality of characters 300, and may acquire the aspect ratios RC1 of the image areas 350 for the plurality of representative characters 310 based on the scanned image IM0. In the adjustment process, the control unit 40 may determine whether the difference between the aspect ratio RC1 of the image area 350 and the reference aspect ratio RC0 (e.g., character expansion / contraction ratio r1 or its reciprocal 1 / r1) for each of the plurality of representative characters 310 exceeds a threshold value TH1, and may adjust the expansion / contraction ratio so that the aspect ratio RC1 of the image area 350 approaches the reference aspect ratio RC0 when the difference (r1 or 1 / r1) for all of the plurality of representative characters 310 exceeds the threshold value TH1. In the above cases, the expansion / contraction ratio of the read image IM0 is adjusted after it is confirmed that the expansion / contraction ratio of the multiple representative characters 310 exceeds the threshold value TH1, thereby improving the accuracy of adjusting the expansion / contraction ratio of the read image.

[0016] [Aspect 5] The scanned image IM0 may have a plurality of pages PE0. The control unit 40 may perform the extraction process and the acquisition process in units of pages PE0, as illustrated in FIG. In the above case, the aspect ratio RC1 of the image area 350 of the representative character 310 is acquired for each page PE0, so that the accuracy of adjusting the expansion / contraction ratio of the read image can be improved.

[0017] [Aspect 6] 6, the control unit 40 may perform the extraction process and the acquisition process on the plurality of pages PE0. After the scanned image IM0 having the plurality of pages PE0 is generated, the control unit 40 may adjust the expansion / contraction ratio of the scanned image IM0 based on the aspect ratio RC1 of the image area 350 of the plurality of pages PE0 in the adjustment process so that the aspect ratio RC1 of the image area 350 approaches the reference aspect ratio RC0. In the above cases, the aspect ratio RC1 of the image area 350 is based on the entire job, so the accuracy of adjusting the expansion / contraction ratio of the read image can be improved.

[0018] [Aspect 7] 7, in the acquisition process, the control unit 40 may divide the scanned image IM0 into a plurality of areas A0 in the horizontal direction (e.g., the X direction) and extract the representative character 310 if the representative character 310 exists in each of the areas A0. In the adjustment process, if a plurality of representative characters 310 exist, the control unit 40 may calculate a character expansion / contraction ratio r1 of the aspect ratio RC1 of the image area 350 relative to the reference aspect ratio RC0 for each of the representative characters 310. The control unit 40 may adjust the expansion / contraction rate of the scanned image IM0 based on the character expansion / contraction ratio r1.

[0019] In the above cases, the expansion / contraction ratio of the read image IM0 is adjusted based on the character expansion / contraction ratio r1 of the representative character 310 extracted from multiple locations in the horizontal direction (X direction), thereby improving the accuracy of adjusting the expansion / contraction ratio of the read image. Here, the division into regions may be performed on the entire scanned image, or on character block regions in which a plurality of characters are gathered in the scanned image.

[0020] [Aspect 8] 7, in the acquisition process, the control unit 40 may divide the scanned image IM0 into a plurality of areas A0 in the vertical direction (e.g., the Y direction) and extract the representative character 310 if the representative character 310 exists in each of the areas A0. In the adjustment process, if a plurality of representative characters 310 exist, the control unit 40 may calculate a character expansion / contraction ratio r1 of the aspect ratio RC1 of the image area 350 relative to the reference aspect ratio RC0 for each of the representative characters 310. The control unit 40 may adjust the expansion / contraction rate of the scanned image IM0 based on the character expansion / contraction ratio r1.

[0021] In the above cases, the expansion / contraction ratio of the read image IM0 is adjusted based on the character expansion / contraction ratio r1 of the representative character 310 extracted from multiple locations in the vertical direction (Y direction), thereby improving the accuracy of adjusting the expansion / contraction ratio of the read image. Here too, the division into regions may be performed on the entire scanned image, or on character block regions in which multiple characters are gathered in the scanned image.

[0022] [Aspect 9] 2, the reading unit 30 may have a moving unit 35 that changes the reading position of the original document D0, and may read the original document D0 while changing the reading position. The read image IM0 may include an acceleration region IA1 read while the moving unit 35 is accelerating, a constant speed region IA2 read while the moving unit 35 is moving at a constant speed, and a deceleration region IA3 read while the moving unit 35 is decelerating. In the acquisition process, the control unit 40 may acquire, based on the read image IM0, an aspect ratio RC1 of the image region 350 of the representative character 310 in the acceleration region IA1, an aspect ratio RC1 of the image region 350 of the representative character 310 in the constant speed region IA2, and an aspect ratio RC1 of the image region 350 of the representative character 310 in the deceleration region IA3. In the adjustment process, the control unit 40 may adjust the expansion / contraction rate of the acceleration region IA1 so that the aspect ratio RC1 of the image region 350 of the representative character 310 in the acceleration region IA1 approaches the reference aspect ratio RC0. The control unit 40 may adjust the expansion / contraction rate of the constant speed region IA2 so that the aspect ratio RC1 of the image region 350 of the representative character 310 in the constant speed region IA2 approaches the reference aspect ratio RC0. The control unit 40 may adjust the expansion / contraction rate of the deceleration region IA3 so that the aspect ratio RC1 of the image region 350 of the representative character 310 in the deceleration region IA3 approaches the reference aspect ratio RC0. In the above case, the expansion / contraction ratios of the acceleration area IA1, the constant speed area IA2, and the deceleration area IA3 are adjusted separately in accordance with the expansion / contraction of the characters within the areas, thereby improving the accuracy of adjusting the expansion / contraction ratio of the scanned image.

[0023] [Aspect 10] 1, the image processing device U0 may further include an operation unit 51 that accepts an operation. As shown in FIG. 10, when the operation unit 51 accepts an operation to adjust the expansion / contraction ratio RR1 as the operation, the control unit 40 may perform the extraction process, the acquisition process, and the adjustment process. In the above case, the read image IM0 is adjusted when the user performs an adjustment operation for the expansion / contraction ratio RR1, so that convenience can be further improved.

[0024] [Aspect 11] Incidentally, an image processing method according to one embodiment includes the following steps, as exemplified in FIG. (a1) An extraction step ST1 in which one or more characters 300 are extracted from a read image IM0 of a document D0 by performing character recognition processing on the read image IM0. (a2) An acquisition step ST2 of acquiring, based on the read image IM0, the aspect ratio RC1 of the image area 350 of the representative character 310 corresponding to the reference character 200 linked to the reference aspect ratio RC0 among the one or more characters 300. (a3) An adjustment step ST3 of adjusting the expansion / contraction ratio of the read image IM0 so that the aspect ratio RC1 of the image area 350 approaches the reference aspect ratio RC0. The above embodiment also improves convenience because the expansion / contraction ratio of the read image IM0 is automatically adjusted even if the size of the original document D0 is unknown.

[0025] Furthermore, the above-described aspects are applicable to an image processing system including the above-described image processing device, a control method for the image reading system, a control program for the above-described image processing device, a control program for the above-described image reading system, a computer-readable non-transitory medium on which any of the above-described control programs is recorded, etc. Any of the above-described devices may be composed of multiple distributed parts.

[0026] (2) Specific examples of image processing devices: FIG. 1 is a block diagram showing a typical configuration of an image processing device U0. FIG. 2 shows a typical structure of a scanner 1 as an example. FIG. 3 shows a typical structure of a reference character table TA1 stored in a storage unit 60. FIG. 4 shows a typical principle of adjusting the expansion / contraction ratio of a scanned image IM0 of a document D0. FIG. 5 shows a typical page PE0 of the scanned image IM0. 1 means at least one of the scanner 1 and the external device 100. In other words, the image processing device U0 may be the scanner 1 alone, the external device 100 alone, or a combination of the scanner 1 and the external device 100. The image reading device that reads the original D0 only needs to include the reading unit 30, and may be the scanner 1 alone or a combination of the scanner 1 and the external device 100.

[0027] The control unit 40 of the scanner 1 includes a central processing unit (CPU) 41, a read-only memory (ROM) 42, a random access memory (RAM) 43, an interface (I / F) 44, and an application-specific integrated circuit (ASIC) 45. The aforementioned elements (41-45) are electrically connected and can exchange information with one another. The control unit 40 can perform character recognition processing based on the pixel values of multiple pixels included in the scanned image IM0. The control unit 40 can also be considered a processor and may include a CPU instead of an ASIC, an ASIC instead of a CPU, or multiple CPUs. The ROM 42 and RAM 43 are semiconductor memories. The I / F 44 is connected to the I / F 117 of the external device 100. The ASIC 45 is connected to a memory unit 60 that stores a reference character table TA1 and the like, a scanning unit 30 that scans the document D0, a display unit 50, an operation unit 51, and the like. Examples of the storage unit 60 include non-volatile semiconductor memory such as flash memory, and magnetic storage devices such as hard disks. The reading unit 30 reads the original document D0 and generates a read image IM0 adjusted to the set expansion / contraction ratio RR0. The display unit 50 displays information such as the status of the scanner 1 and information input from the operation unit 51. Examples of the display unit 50 include a liquid crystal display panel, a light-emitting diode, and a combination thereof. The operation unit 51 accepts various operations. Examples of the operation unit 51 include hard keys, a touch panel attached to the display unit 50, etc.

[0028] 1 includes a CPU 111, a ROM 112, a RAM 113, a storage unit 114, an input unit 115, a display unit 116, and an I / F 117. The above-mentioned elements (111 to 117) are electrically connected to each other and are capable of inputting and outputting information to and from each other. Examples of the external device 100 include a personal computer, a tablet terminal, a mobile phone such as a smartphone, etc. The storage unit 114 stores an operating system (OS), a scanner driver DR1, and the like (not shown). When the image processing device U0 refers to at least the external device 100, the scanner driver DR1 causes the external device 100, which is a computer, to function as the image processing device U0. In this case, the storage unit 114 is an element included in the storage unit 60 that stores the reference aspect ratio RC0 for the reference character 200. The storage unit 114 may be a non-volatile semiconductor memory such as a flash memory, a magnetic storage device such as a hard disk, or the like. The input unit 115 may be a pointing device, hard keys including a keyboard, a touch panel attached to the surface of a display panel, or the like. The input unit 115 as the image processing device U0 is an element included in the operation unit 51 that accepts operations. The display unit 116 may be a liquid crystal display panel or the like. The display unit 116 may be provided external to the external device 100.

[0029] The scanner 1 shown in Fig. 2 includes a main body 2 having a flatbed document table 20 on its upper surface, and an upper cover 3 having an ADF (automatic document feeder) function. The main body 2 includes a horizontal movement unit 31, a control unit 40, an upper cover sensor 21 that detects whether the upper cover 3 is closed, etc. The upper cover 3 includes an original support unit 10 that supports an original D0 to be fed to the reading unit 30, a feeding unit 15 that feeds the original D0 from the original support unit 10 to the reading unit 30, an output tray 19, etc. The original support unit 10 is provided with an original detection sensor 11 that detects whether an original D0 is placed on it. The reading unit 30 includes a moving unit 35 that changes the reading position of the original D0, which includes the horizontal movement unit 31 and the feeding unit 15.

[0030] The horizontal movement unit 31 is capable of reciprocating along a horizontal guide rail 33 facing in the Y direction. The horizontal movement unit 31 has a line sensor 32 facing horizontally perpendicular to the guide rail 33, a light source (not shown), a light guide (not shown), a lens (not shown), etc., and is moved along the guide rail 33 by a drive unit (not shown). When an original D0 is placed on the platen 20, the line sensor 32 reads an image of the original D0 while moving in a direction along the guide rail 33. The reading unit 30 generates a two-dimensional read image IM0 based on the output of the line sensor 32 at each position along the guide rail 33 and outputs the image to the control unit 40. Note that the line sensor 32 can be a solid-state imaging element such as a CMOS (Complementary Metal-Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device) line sensor.

[0031] The feeding section 15 has a feeding roller 16, a discharge roller 17, a transport path 18, etc. The document D0 placed on the document support section 10 is fed into the transport path 18 by the rotation of the feeding roller 16, and is discharged from the transport path 18 to the discharge tray 19 by the rotation of the discharge roller 17. At this time, the horizontal movement unit 31 is positioned so that the line sensor 32 faces the transport path 18, and the reading section 30 generates a two-dimensional read image IM0 based on the output of the line sensor 32 at each timing and outputs it to the control section 40. As described above, the reading unit 30 can perform ADF scanning, in which the original D0 is read while being fed by the feeding unit 15, and flatbed scanning, in which the original D0 is placed on the platen 20. During ADF scanning, the reading unit 30 reads the original D0 while changing the reading position by feeding the original D0 by the feeding unit 15, and generates a read image IM0 adjusted to the set expansion / contraction ratio RR0. The reading unit 30 can generate a read image IM0 adjusted to the set expansion / contraction ratio RR0 by controlling the rotation speed of the rollers (16, 17) to a speed corresponding to the set expansion / contraction ratio RR0. During flatbed scanning, the reading unit 30 reads the original D0 while changing the reading position by moving the horizontal movement unit 31, and generates a read image IM0 adjusted to the set expansion / contraction ratio RR0. The reading unit 30 can generate a read image IM0 adjusted to the set expansion / contraction ratio RR0 by controlling the movement speed of the horizontal movement unit 31 to a speed corresponding to the set expansion / contraction ratio RR0.

[0032] The rollers (16, 17) described above undergo wear and tear over time. The horizontal movement unit 31 also undergoes wear and tear over time. The scanned image IM0 may become stretched or shrunk due to changes in temperature, age, and other factors in the scanning unit 30. While it is conceivable to accept a user-initiated operation to adjust the stretch rate of the scanned image, this relies on the user's perception, leading to variations in the degree to which the stretching or shrunk is noticed and the degree of adjustment. Furthermore, in the case of a scanning contractor or other batch processing company that scans documents in bulk and then checks the scanned images, the moment stretching or shrunk is noticed, much of the document scanning work and a large number of scanned images will have been wasted. In this example, the image processing device U0 extracts characters 300 from a scanned image IM0 using OCR and adjusts the scaling factor of the scanned image IM0 based on the aspect ratio RC1 of an image area 350 of a representative character 310 included in the characters 300. Here, OCR is an abbreviation for Optical Character Reader in terms of the device, and for Optical Character Recognition in terms of optical character recognition. By adjusting the scaling factor based on the aspect ratio RC1 of the image area 350 after OCR, the scaling factor of the scanned image IM0 is automatically adjusted even if the size of the original document D0 is unknown, improving convenience. Furthermore, the document scanning process can be performed efficiently, and waste of the scanned image IM0 can be reduced.

[0033] 3 is stored in the storage unit 60 to adjust the expansion / contraction ratio of the scanned image IM0. The reference character table TA1 has a plurality of reference characters 200 and a reference aspect ratio RC0 associated with each reference character 200. Therefore, it can be said that the storage unit 60 stores the reference aspect ratio RC0 for each reference character 200. The reference characters 200 may be characters that frequently appear in a sentence 301 (see FIG. 5 ) in a document. The reference characters 200 may be letters, Arabic numerals, or the like. The sentence 301 is defined as a portion of the scanned image IM0 where a predetermined number or more of characters 300, for example, 20 or more characters, are consecutive. In the scanned image IM0 shown in FIG. 5 , the extracted characters 300, excluding the heading 302 and the in-image characters 303, tend to use fonts with standard aspect ratios to emphasize readability. Therefore, by storing the aspect ratio of a standard font for the multiple reference characters 200 shown in FIG. 3 as the reference aspect ratio RC0 in the reference character table TA1, it can be used to calculate the character expansion ratio r1. Note that, because special fonts are often used for the heading 302 and the in-image characters 303, in this specific example, a representative character 310 corresponding to the reference character 200 is extracted from the sentence 301.

[0034] The reference aspect ratio RC0 is expressed, for example, as the ratio of the height of the reference character 200 to the width of the reference character 200. In the example of the box 401 in the upper row shown in Fig. 4, the width x0 of the reference character 200 means the length of the reference character 200 in the horizontal direction (X direction), and the height y0 of the reference character 200 means the length of the reference character 200 in the vertical direction (Y direction). In this case, the reference aspect ratio RC0 is y0 / x0. For example, if x0 = y0 = 100, the reference aspect ratio RC0 is 100 / 100 = 1, and if x0 = 100 and y0 = 102, the reference aspect ratio RC0 is 102 / 100 = 1.02.

[0035] The image processing device U0 adjusts the expansion / contraction ratio of the read image IM0, for example, as shown in FIG. The rectangular document D0 shown in the box 401 in the upper row has a reference character 200 with a horizontal length x0 and a vertical length y0. Here, the horizontal length xd of the document D0 refers to the length of the document D0 in the horizontal direction (X direction), and the vertical length yd refers to the length of the document D0 in the vertical direction (Y direction). The reading unit 30 of the scanner 1 reads the document D0 to generate a readout image IM0 as shown in the box 402 in the middle row. The control unit 40 performs OCR on the readout image IM0 to extract one or more characters 300 from the readout image IM0, and extracts a representative character 310 from the one or more characters 300 that corresponds to the reference character 200. FIG. 5 shows multiple representative characters 310 circled. As shown in FIG. 5, it is preferable to extract multiple characters 300 from the readout image IM0 and extract multiple representative characters 310 from the multiple characters 300 that correspond to the reference character 200. FIG. 5 shows a character block area AC1 including one or more sentences 301, and shows that a representative character 310 has been extracted from the character block area AC1.

[0036] The rectangular scanned image IM0 shown in the middle box 402 has an image area 350 of a representative character 310 corresponding to the reference character 200. Here, the horizontal length of scanned image IM0 is xr, the vertical length of scanned image IM0 is yr, the horizontal length of image area 350 is x1, and the vertical length of image area 350 is y1. In this case, the aspect ratio RC1 of image area 350 is y1 / x1. The character expansion ratio r1 is RC1 / RC0, i.e., the ratio of the aspect ratio RC1 of image area 350 to the reference aspect ratio RC0. If scanned image IM0 is elongated in the Y direction, the character expansion ratio r1 is greater than 1. If scanned image IM0 is shrunk in the Y direction, the character expansion ratio r1 is less than 1. The character expansion ratio r1 or its inverse 1 / r1 is an example of the difference between the aspect ratio RC1 of image area 350 and the reference aspect ratio RC0. The aspect ratio yr / xr of the scanned image IM0 itself is estimated to be r1 × yd / xd, obtained by multiplying the aspect ratio yd / xd of the original D0 by the character scaling ratio r1. By adjusting the scaling rate of the scanned image IM0 so that the aspect ratio RC1 of the image area 350 approaches the reference aspect ratio RC0, the character scaling ratio r1 approaches 1, and the aspect ratio of the character 300 in the scanned image IM0 approaches the original aspect ratio y0 / x0.

[0037] The scanned image IM1 shown in the lower box 403 has its scaling factor RR1 adjusted to 1 / r1 = RC0 / RC1. That is, the aspect ratio ys / xs of the scanned image IM1 is RR1 × yr / xr. In this case, the aspect ratio y2 / x2 of the image area 350 is RR1 × y1 / x1 = y1 / x1 / r1, which is the aspect ratio y0 / x0 of the reference character 200 included in the document D0. In this way, even if the size of the original document D0 is unknown, the scanned image IM0 is adjusted to minimize stretching or shrinking. Note that, since it is sufficient that the aspect ratio RC1 of the image area 350 approaches the reference aspect ratio RC0, the expansion / contraction rate RR1 of the scanned image IM0 may be set within a range that does not result in RC0 / RC1. Furthermore, by having the control unit 40 recognize the character orientation in the character recognition process, the expansion / contraction rate of the scanned image IM0 can be adjusted independently of the orientation of the document D0 relative to the scanner 1.

[0038] (3) Specific examples of image generation processing performed by an image processing device: FIG. 6 shows a schematic example of the read image generation process performed by the image processing device U0. In this example, the control unit 40 of the scanner 1 performs the read image generation process. The read image generation process starts when the control unit 40 receives an instruction to read the document D0. The read instruction may be an instruction resulting from pressing a scan start button included in the operation unit 51 of the scanner 1, or an instruction resulting from a predetermined scan start operation on the input unit 115 of the external device 100. Herein, within the read image generation process, the extraction process of step S104 corresponds to the extraction step ST1, the acquisition process of steps S106 to S108 corresponds to the acquisition step ST2, and steps S110 to S120 correspond to the adjustment step ST3. Hereinafter, the word "step" may be omitted, and the step symbol may be shown in parentheses.

[0039] When the scanned image generation process starts, the control unit 40 causes the reading unit 30 to read the document D0 (S102). The reading unit 30 reads the document D0 and generates a scanned image IM0 that has been adjusted using the set expansion / contraction ratio RR0. If the document D0 contains multiple pages, the scanned image IM0 will have pages PE0 equal to the number of pages in the document D0. Next, the control unit 40 sets the page PE0 to be processed and extracts characters 300 from the page PE0 to be processed using OCR (S104). The control unit 40 also recognizes the orientation of the characters in the character recognition process. In S104, the control unit 40 extracts one or more characters 300, preferably multiple characters, from page PE0 of the scanned image IM0 using the character recognition process. Here, the control unit 40 also recognizes whether the character 300 is in a sentence 301 that continues for a predetermined number of characters or more, in a heading 302, or as a character 303 within the image, and uses the one or more characters 300 in the sentence 301 for subsequent processing.

[0040] Next, the control unit 40 refers to the reference character table TA1 and extracts a group of extracted characters included in the sentence 301 shown in Fig. 5, i.e., extracts representative characters 310 corresponding to the reference characters 200 from one or more characters 300 (S106). As illustrated in Fig. 7, the control unit 40 may divide the scanned image IM0 into a plurality of areas A0 in the horizontal direction (X direction) and vertical direction (Y direction), and extract one or more representative characters 310 from each of the areas A0 where a representative character 310 exists.

[0041] FIG. 7 shows a schematic diagram of the division of page PE0 of scanned image IM0 into regions. Page PE0 shown in FIG. 7 is divided into left regions A11, A12, and A13, middle regions A21, A22, and A23, and right regions A31, A32, and A33 in the X direction. Page PE0 is divided into upper regions A11, A21, and A31, middle regions A12, A22, and A32, and lower regions A13, A23, and A33 in the Y direction. The control unit 40 extracts a representative character 310 if it exists in each region A0. Therefore, it can be said that the control unit 40 extracts a representative character 310 if it exists in each region A0 when the scanned image IM0 is divided into multiple regions A0 in the X direction. Furthermore, when the control unit 40 divides the scanned image IM0 into a plurality of areas A0 in the Y direction, if a representative character 310 exists in each area A0, the control unit 40 extracts the representative character 310. The target of dividing the scanned image IM0 into regions is not limited to the entire page PE0, but may be the character block region AC1 (see FIG. 5).

[0042] After extracting one or more representative characters 310, the control unit 40 obtains the aspect ratio RC1=y1 / x1 of the image region 350 of each representative character 310 based on the read image IM0 (S108). The control unit 40 can determine the number of pixels from the leftmost pixel to the rightmost pixel of the representative character 310 in the X direction as the horizontal length x1, and the number of pixels from the topmost pixel to the bottommost pixel of the representative character 310 in the Y direction as the vertical length x1. The control unit 40 then calculates the aspect ratio RC1=y1 / x1.

[0043] After obtaining the aspect ratio RC1, the control unit 40 calculates the character expansion / contraction ratio r1 = RC1 / RC0 of the aspect ratio RC1 of the image area 350 relative to the reference aspect ratio RC0 of the reference character 200 corresponding to the representative character 310 (S110). Next, the control unit 40 determines whether the character expansion / contraction ratio r1 or its inverse 1 / r1 exceeds a predetermined threshold TH1 (S112). Here, the threshold TH1 is a value equal to or greater than 1, preferably a value slightly greater than 1, such as 1.01 to 1.10. If the character expansion / contraction ratio r1 is greater than 1, the control unit 40 determines whether r1 > TH1. If the character expansion / contraction ratio r1 is less than 1, the control unit 40 determines whether 1 / r1 > TH1. If the character expansion / contraction ratio r1 or its inverse 1 / r1 does not exceed the threshold TH1, the scanned image IM0 is not significantly stretched or shrunk, and the control unit 40 terminates the scanned image generation process without performing any adjustment processing.

[0044] If the character expansion / contraction ratio r1 or its inverse 1 / r1 exceeds the threshold value TH1, the character expansion / contraction ratio r1 is not 1. In this case, the control unit 40 determines whether the processes of S108 to S112 have been performed for all of the representative characters 310 on page PE0 (S114). If unprocessed representative characters 310 remain on page PE0, the control unit 40 repeats the processes of S108 to S114. In this way, the control unit 40 performs extraction processing and acquisition processing on the scanned image IM0 in units of pages PE0. By acquiring the aspect ratio RC1 of the image area 350 of the representative character 310 in units of pages PE0, the accuracy of adjusting the expansion / contraction ratio of the scanned image IM0 is improved.

[0045] When the processes of S108 to S112 have been performed for all of the representative characters 310 in page PE0, the control unit 40 determines whether the processes of S104 to S114 have been performed for all of page PE0 of the scanned image IM0 (S116). If an unprocessed page PE0 remains in the scanned image IM0, the control unit 40 repeats the processes of S104 to S116. When the processes of S104 to S114 are performed for all pages PE0 of the scanned image IM0, the tendency of the aspect ratio y1 / x1 of the image area 350 of the representative character 310 is widely recognized within page PE0 and throughout the entire scanned image IM0. In this case, the control unit 40 proceeds to S118. In S118, the control unit 40 calculates one character expansion ratio r2 from the character expansion ratios r1 equal to or greater than 1, determines an expansion ratio RR1 to be applied to the scanned image IM0 based on the character expansion ratio r2, and sets the expansion ratio RR1 as the set expansion ratio RR0 in the scanning unit 30 (S118). The character expansion ratio r2 may be an average value, such as an arithmetic mean value, of the character expansion ratios r1, or may be the median value of the character expansion ratios r1. The expansion ratio RR1 may be 1 / r2 or a value closer to 1 than 1 / r2. For example, when determining the expansion / contraction ratio RR1 so as to eliminate half of the character expansion / contraction ratio r1, the control unit 40 may calculate RR1 = {(1 / r2) + 1} / 2. If k is a coefficient greater than 0 and less than 1, the control unit 40 may calculate RR1 = k × (1 / r2) + (1 - k). In this way, the control unit 40 determines the expansion / contraction ratio RR1 so that the aspect ratio RC1 of the image area 350 approaches the reference aspect ratio RC0 within a range that does not result in the aspect ratio becoming equal to the reference aspect ratio RC0, and applies the determined expansion / contraction ratio RR1 as the set expansion / contraction ratio RR0.

[0046] Finally, the control unit 40 may adjust the read image IM0 in accordance with the expansion / contraction ratio RR1 (S120). The control unit 40 can adjust the expansion / contraction ratio of the read image IM1 so that the adjusted aspect ratio ys / xs (see FIG. 4) becomes RR1×(yr / xr). Even if the process of S120 is not performed, the set expansion / contraction ratio RR0 of the reading unit 30 is updated to the expansion / contraction ratio RR1, and the read image IM0 with the expansion / contraction ratio adjusted is generated by the reading unit 30 the next time a document is read.

[0047] In this way, the control unit 40 determines the expansion / contraction rate RR1 so that the aspect ratio RC1 of the image area 350 approaches the reference aspect ratio RC0, and applies this expansion / contraction rate RR1 as the new set expansion / contraction rate RR0. When slight expansion / contraction occurs in the read image IM0, the image reading device itself fine-tunes the expansion / contraction rate of the read image, so that the expansion / contraction of the read image is not noticeable. Furthermore, when the difference between the aspect ratio RC1 of the image area 350 and the reference aspect ratio RC0 (character expansion / contraction ratio r1 or its reciprocal 1 / r1) for all of the representative characters 310 exceeds a threshold value TH1, the control unit 40 adjusts the expansion / contraction ratio so that the aspect ratio RC1 of the image area 350 approaches the reference aspect ratio RC0. Since the expansion / contraction ratio of the read image IM0 is adjusted after it is confirmed that the expansion / contraction of the representative characters 310 exceeds the threshold value TH1, the accuracy of adjusting the expansion / contraction ratio of the read image is good.

[0048] When the read image IM0 has multiple pages PE0, the control unit 40 adjusts the expansion / contraction ratio of the read image IM0 based on the aspect ratio RC1 of the image area 350 that covers the multiple pages PE0 so that the aspect ratio RC1 of the image area 350 approaches the reference aspect ratio RC0. Because the aspect ratio RC1 of the image area 350 is based on the entire job, the expansion / contraction ratio of the read image can be adjusted with good accuracy. When there are multiple representative characters 310, the control unit 40 calculates the character expansion ratio r2 to be applied to the read image IM0 from the character expansion ratio r1 of the multiple representative characters 310 extracted from multiple locations in the X and Y directions, and adjusts the expansion rate of the read image IM0 based on the character expansion ratio r2. This ensures good accuracy in adjusting the expansion rate of the read image.

[0049] By applying the set expansion / contraction rate RR0 so that the aspect ratio RC1 of the image area 350 approaches the reference aspect ratio RC0 without becoming the reference aspect ratio RC0, the expansion / contraction of the characters in the read image IM0 between documents D0 is not noticeable, as shown in Fig. 8. Fig. 8 shows a schematic example of the reading results between documents D0. Based on the scanned image IM0, a scaling factor RR1 = RC0 / RC1 is set in the scanning unit 30 as the set scaling factor RR0, so that the aspect ratio RC1 of the image area 350 of the representative character 310 becomes the reference aspect ratio RC0. In this case, scanned image IM3 is generated according to the set scaling factor RR0, and the aspect ratio RC1 of the image area 350 of the representative character 310 is adjusted to the reference aspect ratio RC0. If the process of S120 shown in FIG. 6 is not performed, the characters in the scanned image may be significantly stretched or shrunk between documents D0, causing a sense of discomfort to the user. Therefore, by setting the scaling factor RR1 = k × (1 / r2) + (1 − k) in the scanning unit 30 as the set scaling factor RR0, scanned images IM0, IM1, IM2, and IM3 are generated in this order, reducing the amount of stretching or shrunk of the characters in the scanned image between documents D0. This prevents noticeable changes in character stretching or shrunk even if the scaling factor RR1 of the scanned image IM0 changes between documents D0. Even if a misadjustment occurs due to a document using a special font being read, the sense of incongruity can be reduced by using a mechanism that prevents drastic changes.

[0050] As explained above, since the reference aspect ratio RC0 of the reference character 200 is known, the aspect ratio RC1 of the image area 350 of the representative character 310 approaches the reference aspect ratio RC0, and the scanned image IM0 is adjusted to reduce stretching and shrinkage. In this way, the expansion / contraction ratio RR1 of the scanned image IM0 is automatically adjusted even if the size of the original document D0 is unknown, so this specific example can improve convenience.

[0051] (4) Variation: The present invention can be embodied in various modifications. 6 may be performed by the external device 100 and the scanner 1. When the scanner 1 transmits the read image IM0 to the external device 100, the external device 100 may perform the processes of S104 to S120 on the read image IM0. By inputting an already generated scanned image IM0, the image processing device U0 can check whether the scanned image IM0 has been expanded or contracted, and can adjust the expansion / contraction ratio of the scanned image IM0. The control unit 40 may display the coefficient k for calculating the expansion / contraction rate RR1={(1 / r2)+1} / 2 on the display unit 50, and the operation unit 51 may accept manual adjustment of the coefficient k. The control unit 40 may adjust the expansion / contraction rate of the scanned image IM0 only for a specific region of the scanned image IM0 by limiting the target of judgment of the scanned image IM0 to that specific region. For example, it is conceivable that the speed at which the horizontal movement unit 31 that realizes flatbed scanning slides at a specific position may change due to malfunction or deterioration over time. In this case, the control unit 40 may adjust the expansion / contraction rate of the scanned image IM0 only for the region of the scanned image IM0 where the speed has changed. The control unit 40 may determine the expansion / contraction ratio RR1 for each page PE0 and apply the adjustment of the expansion / contraction ratio to the page PE0.

[0052] As illustrated in Fig. 9, the read image IM0 may be divided into regions according to the acceleration caused by the moving unit 35 (see Fig. 2) of the reading unit 30. Fig. 9 illustrates a schematic example of adjusting the expansion / contraction ratios of the acceleration region IA1, the constant speed region IA2, and the deceleration region IA3 in the read image IM0. The scanned image IM0 includes an acceleration area IA1 scanned while the moving unit 35 was accelerating, a constant speed area IA2 scanned while the moving unit 35 was moving at a constant speed, and a deceleration area IA3 scanned while the moving unit 35 was decelerating. During ADF scanning, accelerating by the moving unit 35 means that the document D0 is accelerating, constant speed movement by the moving unit 35 means that the document D0 is moving at a constant speed, and deceleration by the moving unit 35 means that the document D0 is decelerating. During flatbed scanning, accelerating by the moving unit 35 means that the horizontal movement unit 31 is accelerating, constant speed movement by the moving unit 35 means that the horizontal movement unit 31 is moving at a constant speed, and deceleration by the moving unit 35 means that the horizontal movement unit 31 is decelerating. The range of each area (IA1, IA2, IA3) is determined by the specifications of the scanner 1.

[0053] The control unit 40 adjusts the expansion / contraction ratio of the scanned image IM0 in accordance with the scanned image generation process shown in Fig. 6. In S108 shown in Fig. 6, the control unit 40 acquires the aspect ratios RC11, RC12, and RC13 of the image region 350 of the representative character 310 in each of the acceleration region IA1, constant speed region IA2, and deceleration region IA3 based on the scanned image IM0. The control unit 40 then divides the region into the acceleration region IA1, constant speed region IA2, and deceleration region IA3 and performs the adjustment process of S110 to S120. The control unit 40 determines the expansion / contraction ratio RR11 of the acceleration region IA1 so that the aspect ratio RC11 of the image region 350 of the representative character 310 in the acceleration region IA1 approaches the reference aspect ratio RC0. The control unit 40 determines the expansion / contraction ratio RR12 of the constant speed region IA2 so that the aspect ratio RC12 of the image region 350 of the representative character 310 in the constant speed region IA2 approaches the reference aspect ratio RC0. The control unit 40 determines the expansion / contraction rate RR13 of the deceleration area IA3 so that the aspect ratio RC13 of the image area 350 of the representative character 310 in the deceleration area IA3 approaches the reference aspect ratio RC0. In the example shown in FIG. 9, the expansion / contraction ratios of the acceleration area IA1, the constant speed area IA2, and the deceleration area IA3 are adjusted separately in accordance with the expansion / contraction of the characters within the areas, improving the accuracy of adjusting the expansion / contraction ratio of the scanned image.

[0054] 10, the expansion / contraction ratio of the scanned image IM0 may be adjusted when an adjustment is instructed in manual adjustment mode. FIG. 10 schematically illustrates a manual adjustment process performed by the image processing device U0. The manual adjustment process starts when the operation unit 51 notifies the control unit 40 that an operation has been accepted. Of course, the manual adjustment process may also start when the external device 100 notifies the scanner 1 that the input unit 115 of the external device 100 has accepted an operation as the operation unit 51.

[0055] When the manual adjustment process starts, the control unit 40 determines whether the operation unit 51 has received an adjustment execution operation for the expansion / contraction rate RR1 as an operation (S202). If the operation of the operation unit 51 is an adjustment execution operation, the control unit 40 performs the read image generation process shown in FIG. 6 (S204). If the operation of the operation unit 51 is not an adjustment execution operation, the control unit 40 does not perform the read image generation process. Therefore, when the operation unit 51 receives an adjustment execution operation for the expansion / contraction rate RR1 as an operation, the control unit 40 performs the extraction process, the acquisition process, and the adjustment process. In the example shown in FIG. 10, the read image IM0 is adjusted when the user performs an adjustment execution operation for the expansion / contraction ratio RR1, which further improves convenience.

[0056] (5) Conclusion: As explained above, according to various aspects of the present invention, it is possible to provide a highly convenient configuration in which the expansion / contraction ratio of a scanned image is automatically adjusted even if the size of the original document is unknown. Of course, even in an aspect consisting only of the features of the independent claims, the basic functions and effects described above can be obtained. Furthermore, it is possible to implement configurations in which the components disclosed in the above examples are substituted with each other or the combination is changed, or configurations in which the components disclosed in the publicly known techniques and the above examples are substituted with each other or the combination is changed, etc. The present invention also includes these configurations. [Explanation of symbols]

[0057] 1...scanner, 10...original support section, 15...feed section, 20...original table, 30...reading section, 31...horizontal movement unit, 35...movement section, 40...control section, 51...operation section, 60...storage section, 100...external device, 115...input section, 200...reference character, 300...character, 301...sentence, 302...heading, 303...character in image, 310...representative character, 350...image area, A0...area, AC1...character block area, D0... Original, IA1...acceleration area, IA2...constant speed area, IA3...deceleration area, IM0, IM1, IM2, IM3...read image, PE0...page, r1...character expansion ratio, RC0...reference aspect ratio, RC1...aspect ratio of image area, RR0...set expansion ratio, RR1...expansion ratio of read image, ST1...extraction process, ST2...acquisition process, ST3...adjustment process, TA1...reference character table, TH1...threshold value, U0...image processing device.

Claims

1. a control unit capable of executing character recognition processing on a scanned image of a document; a storage unit that stores a reference aspect ratio for a reference character; The control unit performing an extraction process to extract one or more characters from the read image by the character recognition process; performing an acquisition process for acquiring an aspect ratio of an image area of a representative character corresponding to the reference character among the one or more characters based on the scanned image; An image processing device capable of performing an adjustment process for adjusting a scaling ratio of the read image so that the aspect ratio of the image area approaches the reference aspect ratio.

2. a reading unit that reads the document and generates the read image that has been adjusted to the set expansion / contraction ratio; The image processing device according to claim 1 , wherein the control unit determines the expansion / contraction ratio in the adjustment process so that the aspect ratio of the image area approaches the reference aspect ratio, and applies the determined expansion / contraction ratio as the new set expansion / contraction ratio.

3. 3. The image processing device according to claim 2, wherein the control unit, in the adjustment process, determines the expansion / contraction ratio so that the aspect ratio of the image area approaches the reference aspect ratio within a range that does not become the reference aspect ratio, and applies the determined expansion / contraction ratio as the set expansion / contraction ratio.

4. The control unit In the extraction process, a plurality of characters are extracted from the read image by the character recognition process; In the acquisition process, a plurality of representative characters are extracted from the plurality of characters, and aspect ratios of the image regions of the plurality of representative characters are acquired based on the read image; 2. The image processing device according to claim 1, wherein the adjustment process determines whether the difference between the aspect ratio of the image area and the reference aspect ratio for each of the plurality of representative characters exceeds a threshold value, and if the difference exceeds the threshold value for all of the plurality of representative characters, adjusts the expansion / contraction rate so that the aspect ratio of the image area approaches the reference aspect ratio.

5. the scanned image has a plurality of pages, The image processing device according to claim 1 , wherein the control unit performs the extraction process and the acquisition process on a page-by-page basis.

6. the scanned image has a plurality of pages, 2. The image processing device according to claim 1, wherein the control unit performs the extraction process and the acquisition process on the plurality of pages, and after the read image having the plurality of pages is generated, in the adjustment process, adjusts the expansion / contraction ratio of the read image based on the aspect ratio of the image area targeted for the plurality of pages so that the aspect ratio of the image area approaches the reference aspect ratio.

7. The control unit In the acquisition process, when the scanned image is divided into a plurality of regions in the horizontal direction, if the representative character exists in each of the regions, the representative character is extracted; An image processing device according to any one of claims 1 to 6, wherein, in the adjustment process, if there are multiple representative characters, a character expansion ratio of the aspect ratio of the image area relative to the reference aspect ratio is calculated for each representative character, and the expansion rate of the read image is adjusted based on the character expansion ratio.

8. The control unit In the acquisition process, when the scanned image is divided into a plurality of regions in the vertical direction, if the representative character exists in each of the regions, the representative character is extracted; An image processing device according to any one of claims 1 to 6, wherein, in the adjustment process, if there are multiple representative characters, a character expansion ratio of the aspect ratio of the image area relative to the reference aspect ratio is calculated for each representative character, and the expansion rate of the read image is adjusted based on the character expansion ratio.

9. a reading unit that has a moving unit that changes a reading position of the document, reads the document while changing the reading position, and generates the read image in which the set expansion / contraction ratio has been adjusted; the read image includes an acceleration region read when the moving unit is accelerating, a constant speed region read when the moving unit is moving at a constant speed, and a deceleration region read when the moving unit is decelerating, The control unit In the acquisition process, an aspect ratio of the image area of the representative character in the acceleration region, an aspect ratio of the image area of the representative character in the constant speed region, and an aspect ratio of the image area of the representative character in the deceleration region are acquired based on the read image; An image processing device as described in any one of claims 1 to 6, wherein in the adjustment process, the expansion / contraction rate of the acceleration region is adjusted so that the aspect ratio of the image region of the representative character in the acceleration region approaches the reference aspect ratio, the expansion / contraction rate of the constant speed region is adjusted so that the aspect ratio of the image region of the representative character in the constant speed region approaches the reference aspect ratio, and the expansion / contraction rate of the deceleration region is adjusted so that the aspect ratio of the image region of the representative character in the deceleration region approaches the reference aspect ratio.

10. further comprising an operation unit that accepts operations, The image processing device according to any one of claims 1 to 6, wherein the control unit performs the extraction process, the acquisition process, and the adjustment process when the operation unit receives an operation to adjust the stretch ratio as the operation.

11. an extraction step of extracting one or more characters from the read image of the document by performing character recognition processing on the read image; an acquisition step of acquiring, based on the scanned image, an aspect ratio of an image area of a representative character corresponding to a reference character associated with a reference aspect ratio among the one or more characters; an adjustment step of adjusting the expansion / contraction ratio of the read image so that the aspect ratio of the image area approaches the reference aspect ratio.

Images