JP4883042B2 - Image processing apparatus, image forming apparatus, and image processing program - Google Patents

Description

  The present invention relates to an image processing apparatus such as a printer, a copying machine, a facsimile apparatus, and a personal computer that processes an image, and more particularly to an image processing apparatus having a function of adding an additional image such as a watermark.

  2. Description of the Related Art Conventionally, there is an image forming apparatus that has a function of adding a character string or graphics watermark to an image input from an image reading unit or an external device.

  This watermark is sometimes called a watermark image or the like, and is often used for printing graphics such as a company logo, or a character string such as “copy prohibited”, “confidential”, or “confidential”.

  In addition, there is one that can be added to an image by tilting the watermark to a desired angle. In this case, there is an annoyance that the user has to specify an angle value.

Patent Document 1 discloses an image forming apparatus in which a user can add a watermark on a diagonal line of a sheet without setting the angle of the watermark.
JP 2000-25278 A

  However, in the image forming apparatus disclosed in Patent Document 1, although the watermark can be added on the diagonal line of the paper without the user setting the angle, the watermark of the image to which the watermark is added is described. The angle was not taken into account. For this reason, when characters are included in the image, the watermark may cover the characters formed on the paper, making the characters difficult to see.

  The present invention has been made in view of the above problems, and tilts an additional image such as a watermark in a direction intersecting the arrangement direction of characters formed on a sheet without the user setting an angle. Therefore, it is an object of the present invention to provide an image processing apparatus that can improve the visibility of characters without the additional image covering the characters.

In order to achieve the above object, an image processing apparatus according to a first aspect of the present invention is detected by a character arrangement direction detection unit that detects an arrangement direction of characters formed on a recording medium and the character arrangement direction detection unit. A direction changing unit that changes the direction of the additional image in a direction that intersects the character arrangement direction, and an additional image whose direction has been changed by the direction changing unit to the character formed on the recording medium. The direction changing unit includes an intersection determining unit that determines whether or not an angle at which the direction of the additional image intersects the character arrangement direction is a predetermined angle intersection range; When the intersection determination unit determines that it is within the predetermined intersection angle range, the direction of the additional image is not changed, and when it is determined that the additional image is outside the predetermined intersection angle range, the direction of the additional image is set to the direction of the additional image. And the character array direction It is characterized in that to change so as to intersect at a predetermined angle.

  According to a second aspect of the present invention, in the image processing apparatus according to the first aspect, the composition unit adds a plurality of the additional images in a direction intersecting with the character arrangement direction detected by the character arrangement direction detection unit. Thus, a composite image is generated.

  According to a third aspect of the present invention, in the image processing device according to the first or second aspect, the character arrangement direction detection unit detects the presence or absence of characters from an image including characters formed on a recording medium. It has a character detection part, and when the said character detection part detects presence of a character, it detects the arrangement direction of the detected character.

  According to a fourth aspect of the present invention, in the image processing apparatus according to the third aspect, the orientation changing unit defines only the orientation of the additional image added to the character detected by the character detecting unit as a character arrangement direction. The direction is changed to an intersecting direction, and the direction of the additional image added to the image other than the detected character is not changed.

  According to a fifth aspect of the present invention, in the image processing apparatus according to any one of the first to fourth aspects, the orientation changing unit changes the orientation of the additional image in the arrangement direction of characters formed on the recording medium. In contrast, the angle is changed to 90 degrees.

According to a sixth aspect of the present invention, the orientation changing unit includes a hidden image determining unit that determines whether or not the additional image is a hidden image intended to hide characters, and the hidden image determining unit is a hidden image. Is determined, the direction of the additional image is changed to the same direction as the detected character arrangement direction.

According to a seventh aspect of the present invention, there is provided a character arrangement direction detection unit that detects an arrangement direction of characters formed on a recording medium, and an additional image in a direction that intersects the character arrangement direction detected by the character arrangement direction detection unit. A direction changing unit that changes the orientation of the image, a combining unit that generates a composite image by adding an additional image whose direction has been changed by the direction changing unit to characters formed on the recording medium, and a generation unit that generates the combined image. An image forming unit that forms the synthesized image on a recording medium, and the direction changing unit determines whether or not an angle at which the direction of the additional image intersects the character arrangement direction is within a predetermined angle intersection range. When determining that the intersection determination unit is outside the predetermined intersection angle range without changing the orientation of the additional image when the intersection determination unit determines that the intersection determination range is within the predetermined intersection angle range, The direction of the additional image Orientation of the pressure image and said character array direction is characterized in that to change so as to intersect at a predetermined angle.

According to an eighth aspect of the present invention, there is provided a character arrangement direction detection function for detecting an arrangement direction of characters formed on a recording medium, and an additional image in a direction crossing the character arrangement direction detected by the character arrangement direction detection function. An image realized by a computer with a direction changing function for changing the orientation of the image and a composition function for generating a composite image by adding an additional image whose orientation has been changed by the orientation change function to characters formed on a recording medium In the processing program, the direction changing function has an intersection determination function for determining whether an angle at which the direction of the additional image intersects the character arrangement direction is a predetermined angle intersection range, When the determination function determines that it is within the predetermined crossing angle range, the direction of the additional image is not changed, and when it is determined that it is outside the predetermined crossing angle range, the direction of the additional image is changed to the additional image. Orientation and said character array direction is characterized in that to change so as to intersect at a predetermined angle.

According to the first aspect of the present invention, the orientation of the additional image is changed in a direction crossing the arrangement direction of the characters formed on the recording medium, and the additional image with the changed orientation is added to the characters to form a composite image. Therefore, the additional image does not cover the character, and the visibility of the character can be improved. Further, if the angle at which the direction of the additional image intersects the character arrangement direction is within a predetermined crossing angle range, the direction of the additional image is not changed, so that it is not necessary to perform complicated processing. Further, if it is outside the predetermined intersection angle range, the orientation of the additional image is changed so as to intersect the character arrangement direction at a predetermined angle, so that the visibility of the characters can be improved.

  According to the second aspect of the present invention, a plurality of the additional images are added in a direction crossing the character arrangement direction. By adding a plurality of additional images, the function of the additional image, for example, the function of a watermark image is ensured, and the additional image does not cover the characters, and the visibility of the characters can be improved.

  According to the third aspect of the present invention, when the presence of a character is detected from an image including the character formed on the recording medium, the detected arrangement direction of the character is detected. In the case of an image including characters, the direction of the additional image is changed in a direction intersecting the character arrangement direction, and the image is added to the character. Even when characters and images other than characters coexist, the additional image does not cover the characters, and the visibility of the characters can be improved.

  According to the invention of claim 4, only the direction of the additional image added to the detected character is changed to a direction intersecting the character arrangement direction, and the additional image is added to the image other than the detected character. The orientation of the additional image is not changed. In general, complicated processing is required to detect the arrangement direction of images other than characters, and therefore, the direction of the additional image is not changed for images other than characters. As a result, even when characters and images other than characters are mixed, the visibility of the characters can be improved by a relatively simple process.

  According to the invention of claim 5, since the orientation of the additional image is changed to 90 degrees with respect to the arrangement direction of the characters formed on the recording medium, the region where the characters and the additional image overlap is It becomes less than any direction of the additional image, and the visibility of characters can be improved.

According to the sixth aspect of the present invention, when the additional image is a hidden image for the purpose of hiding characters, the direction of the additional image is changed to the same direction as the character arrangement direction. Thereby, the objective of hiding the character of a hidden image can be achieved.

According to the seventh aspect of the present invention, the orientation of the additional image is changed in a direction intersecting the arrangement direction of the characters formed on the recording medium, and the additional image with the changed orientation is converted into characters. Since the composite image is generated by adding, the additional image does not cover the character, and the composite image can be formed on the recording medium in a state where the visibility of the character is improved. Further, if the angle at which the direction of the additional image intersects the character arrangement direction is within a predetermined crossing angle range, the direction of the additional image is not changed, so that it is not necessary to perform complicated processing. Further, if it is outside the predetermined intersection angle range, the orientation of the additional image is changed so as to intersect the character arrangement direction at a predetermined angle, so that the visibility of the characters can be improved.

According to the eighth aspect of the present invention, the orientation of the additional image is changed in a direction intersecting with the arrangement direction of the characters formed on the recording medium, and the additional image with the changed orientation is added to the characters to form a composite image. Therefore, the additional image does not cover the character, and the visibility of the character can be improved. Further, if the angle at which the direction of the additional image intersects the character arrangement direction is within a predetermined crossing angle range, the direction of the additional image is not changed, so that it is not necessary to perform complicated processing. Further, if it is outside the predetermined intersection angle range, the orientation of the additional image is changed so as to intersect the character arrangement direction at a predetermined angle, so that the visibility of the characters can be improved.

[Embodiment]
An embodiment in which the present invention is applied to a multifunctional image forming apparatus will be described below with reference to the accompanying drawings. A multi-function image forming apparatus has a facsimile function, a printer function, a copying function, a scanner function, and the like, and is well known.
<Appearance configuration>
FIG. 1 is a perspective view showing an external configuration of an image forming apparatus 10 according to the present embodiment. As shown in FIG. 1, the image forming apparatus 10 includes a printer unit 20 provided at a lower part, a scanner part 30 provided at an upper part, an operation panel part 40 provided at an upper front part, and a slot part 50 provided at a front part. It has.
The printer unit 20 has an opening 21 on the front. A paper feed tray 22 and a paper discharge tray 23 are provided in the opening 21 in two upper and lower stages. The paper feed tray 22 is for loading recording paper. The recording paper loaded on the paper feed tray 22 is fed into the printer unit 20 and is discharged to the paper discharge tray 23 after a desired image is printed.

  The scanner unit 30 is a flat bed type scanner. The document cover 31 is provided as a top plate of the image forming apparatus 10. A platen glass (not shown) is disposed below the document cover 31. When reading a document, the document cover 31 is opened to the upper side, the document is placed on the platen glass, and the document cover 31 is closed to complete preparation for reading the document. When the user instructs reading of the document, the image of the document is read by an image sensor (not shown) provided on the lower side of the platen glass. For example, when a document configured as a set of characters is described in the manuscript, the document is read by the scanner unit 30.

  The operation panel unit 40 includes a keyboard unit 41 and a display unit 42 such as an LCD. The keyboard unit 41 includes various buttons such as a numeric button, a start button, and a function operation button. The display unit 42 can display a function selection screen for instructing a function to be executed by the user. In addition, the display unit 42 can display the operation procedure and the status of the process being executed, and can also display information corresponding to pressing of the keyboard unit 41.

  The user can instruct setting of various functions and execution of operations by operating the operation panel unit 40. For example, selection of various functions such as facsimile function, printer function, scanner function, copy function, setting of recording paper size and type (plain paper or postcard), setting of single-sided printing mode, setting of double-sided printing mode Etc. can be instructed via the operation panel unit 40.

  In particular, in this embodiment, a watermark function is mounted as a part of the copy function. The watermark function uses, as a watermark, an image stored in a small memory card (to be described later), an image read from an original by the scanner unit 30, or a predetermined frequently used image stored in advance in an EEPROM 84 (to be described later) as a watermark. This is a function for printing a composite image on a recording sheet by compositing a document read from an original by the scanner unit 30. An instruction from the user when executing the watermark function is input via the operation panel unit 40.

The slot unit 50 is configured to be loaded with various small memory cards that are storage media. For example, when the user operates the operation panel unit 40 with the small memory card loaded in the slot unit 50, the image data stored in the small memory card is read, and the read image data is It can be displayed on the display unit 42 or printed on a recording sheet.
<Electrical configuration>
Next, the electrical configuration of the image forming apparatus 10 will be described with reference to FIG.
FIG. 2 is a block diagram illustrating an electrical configuration of the image forming apparatus 10. The image forming apparatus 10 includes a microcomputer mainly composed of a CPU 81, ROM 82, RAM 83, and EEPROM 84. The CPU 81 is connected to the ASIC 86 via the bus 85.

  The CPU 81 controls each function of the image forming apparatus 10 and controls each part connected to the ASIC 86 in accordance with setting values and programs stored in the ROM 82 and RAM 83 or various signals transmitted / received via the NCU 87. It is something to control.

  The ROM 82 stores a program for controlling various operations of the image forming apparatus 10. For example, main processing for combining and printing the additional image and the character shown in the flowchart of FIG. 3, character arrangement direction detection processing for detecting the character arrangement direction shown in the flowchart of FIG. 4, and the additional image shown in the flowchart of FIG. A program for causing the image forming apparatus 10 to execute an additional image orientation changing process for changing the orientation is stored in the ROM 82. The RAM 83 is used as a storage area for temporarily storing various data used when the CPU 81 executes these programs, and as a work area. The RAM 83 includes an additional image data memory 83a, a change forward data memory 83b, a document data memory 83c, a transmittance data memory 83d, a density distribution data memory 83e, a character arrangement direction data memory 83f, an intersection angle range data memory 83g, Storage areas of an angular direction data memory 83h, a changed backward data memory 83i, an arrangement interval data memory 83j, and a composite image data memory 83k are allocated.

  The additional image data memory 83a is an area for temporarily storing additional image data to be printed on a recording sheet as a watermark when the watermark function included in a part of the copy function is used. The forward change data memory 83b is an area for temporarily storing the orientation of the additional image stored in the additional image data memory 83a. The document data memory 83c is an area for temporarily storing image data including characters and figures of a document read by the scanner unit 30 that is combined with an additional image as a watermark and printed on a recording sheet. The transmittance data memory 83d is an area for temporarily storing the transmittance of the additional image stored in the additional image data memory 83a. The density distribution data memory 83e is an area for temporarily storing density distribution intervals. The character arrangement direction data memory 83f is an area for temporarily storing the arrangement direction of characters in the original stored in the original data memory 83c. The intersection angle range data memory 83g is an area for temporarily storing the intersection angle range between the character arrangement direction in which the orientation of the additional image is not changed and the additional image. The intersection angle direction data memory 83h is an area for temporarily storing an angle at which the direction of the additional image intersects the character arrangement direction. The post-change direction data memory 83i is an area for temporarily storing the direction of the additional image changed according to the character arrangement direction stored in the character arrangement direction data memory 83f. The arrangement interval data memory 83j is an area for temporarily storing the arrangement interval between additional images. The composite image data memory 83k is an area for temporarily storing composite image data to be printed on recording paper by the watermark function.

  The EEPROM 84 stores settings, flags, and the like that should be retained even after the power is turned off. For example, an additional image captured from the slot unit 50 can be saved. Thereby, the additional image once taken can be repeatedly used. As described above, the EEPROM 84 also stores in advance predetermined additional images that are frequently used.

  The ASIC 86 controls peripheral devices such as a connected printer unit in accordance with a command from the CPU 81.

  The printer unit 20 forms an image on a recording sheet in response to a print command signal from the ASIC 86. The scanner unit 30 reads an image or character of a document in response to a read command signal from the ASIC 86 and outputs the read image data to the ASIC 86. The operation panel unit 40 detects an operation state of the keyboard unit 41 of the operation panel unit 40 based on a detection command signal from the ASIC 86 and outputs the detected operation data to the ASIC 86. The operation panel unit 40 supplies image display data to the display unit 42 in response to an instruction command signal from the ASIC 86. The slot unit 50 reads the image data stored in the small memory card in response to a read command signal from the ASIC 86 and outputs the read image data to the ASIC 86.

  The ASIC 86 is connected to an NCU (Network Control Unit) 87. The NCU 87 is configured to input a communication signal from a public line. The modem 88 demodulates the input communication signal and inputs it to the ASIC 86. When the ASIC 86 transmits image data to the outside by facsimile transmission or the like, the modem 88 modulates the image data into a communication signal and outputs the communication signal to the public line via the NCU 87. .

The parallel interface 89 transmits / receives data to / from an external device such as a personal computer via a parallel cable according to a communication control signal from the ASIC 86. The USB interface 90 transmits / receives data to / from an external device such as a personal computer via a USB cable according to a communication control signal from the ASIC 86.
<Operation of Embodiment>
Hereinafter, the operation of the image forming apparatus 10 according to the present exemplary embodiment will be described with reference to FIGS. 3 to 9. Here, FIG. 6 is a diagram conceptually showing the contents of image data including characters and graphics of a document read by the scanner unit 30 and stored in the document data memory 83c. The image forming area GR is determined according to the size of the recording paper set by the operation panel unit 40. On the image forming area GR, a character group M1 in the B line direction, that is, horizontal writing direction, a character group M2 in the A line direction, that is, vertical writing direction, and a figure group M3 are described. FIG. 9 is a diagram conceptually showing the contents of the composite image data stored in the composite image data memory 83k. With respect to the character arrangement direction of the character group M1, the orientation of the additional image WM is changed to a direction rotated 45 degrees counterclockwise as indicated by an angle θ1 in FIG. Further, the orientation of the additional image WM with respect to the character arrangement direction of the character group M2 is changed to a direction rotated 45 degrees counterclockwise as indicated by an angle θ2 in FIG. The orientation of the additional image WM is not changed with respect to the graphic group M3. 7 and 8 are diagrams showing the density distribution of the character group M1 in the horizontal writing direction and the density distribution of the character group M2 in the vertical writing direction, respectively.
(Main process)
First, with reference to FIG. 3, the main process of watermark copy executed by the CPU 81 of the image forming apparatus 10 will be described. FIG. 3 is a flowchart showing main processing of the image forming apparatus 10. This main process is a process executed when a copy function is selected from various functions such as a facsimile function, a printer function, a scanner function, and a copy function through the operation of the operation panel 40 by the user. In particular, the main process is to add a watermark in a direction that intersects the direction of arrangement of the characters formed on the recording paper, and to compose the watermark without covering the character. Includes processing to enhance sex.

  In this main process, first, it is determined whether a watermark copy has been selected (S1). In this embodiment, when the copy function is selected by the user, the display unit 42 displays a request for selecting a copy type such as watermark copy, normal copy, double-sided copy, and the like. It is judged whether it was done. When the watermark is not selected (S1: NO), the main process ends. After the main process is completed, the image forming apparatus 1 executes other functions such as a facsimile function by a known processing unit until the copy function is selected.

  On the other hand, when watermark copying is selected (S1: YES), additional image candidates to be used as watermarks are displayed on the display unit 42 (S2). As described above, the displayed additional image is an image stored in a small memory card, an image read from a document by the scanner unit 30, or a predetermined image stored in advance in the EEPROM 91.

  It waits until a predetermined additional image is selected from the watermark candidates displayed by the display unit 42 (S3: NO). When a predetermined additional image is selected (S3: YES), the selected additional image is selected. The additional image is stored in the additional image data memory 83a (S4). The orientation of the additional image stored in the additional image data memory 83a is stored in the forward change data memory 83b (S5).

  It is determined whether or not the user inputs “scan OK” via the keyboard unit 41 (S6). It waits until “Scan OK” is input (S6: NO), and when “Scan OK” is input (S6: YES), the scanner unit 30 is activated and placed on the platen glass by the scanner unit 30. An image including characters and figures described in the document being read is read (S7). An image including the read characters and graphics is stored in the document data memory 83c (S8).

  A transmittance setting process is performed (S9). In the transmittance setting process, for example, as the transmittance of the additional image, any numerical value from “0%” to “100%” is set by the key operation of the keyboard unit 41 and displayed on the display unit 42. The set transmittance is stored in the transmittance data memory 83d. The transmittance is a value representing the thinness or darkness of the image, and is determined by the size of the area where the image is formed per unit area. When the area where the image is formed is large, the transmittance is small, and the smallest value is the darkest value with the transmittance “0%”. Further, when the area where the image is formed is small, the transmittance is large, and the largest value is the thinnest value of the transmittance “100%”.

  In order to detect the arrangement direction of the characters in the document stored in the document data memory 83c, the character arrangement direction detection process shown in FIG. 4 is executed (S10). Details of the character arrangement direction detection processing will be described later.

  When the character arrangement direction is detected in step S10, an additional image orientation changing process shown in FIG. 5 is executed in order to change the orientation of the additional image (S11). This additional image orientation changing process (S12) is a process of changing the orientation of the additional image added to the character formed on the recording paper in accordance with the character arrangement direction detected in step S10. Details of the additional image orientation changing process will be described later.

  The additional image acquired in step S4 is added to the image including characters and graphics of the document acquired in step S8 and synthesized to create a composite image. First, various setting processes are performed. (S12). In these various setting processes, the arrangement interval of the additional image with respect to the image including characters and graphics of the document is set. For example, the position of the additional image with respect to the image including characters and graphics of the document is determined such that the arrangement interval between two adjacent additional images is a constant interval. The arrangement interval is set by a key operation of the keyboard unit 41. The set arrangement interval is stored in the arrangement interval data memory 83j. As the transmittance of the additional image, the transmittance of the additional image set in step S9 is set. As the orientation of the additional image with respect to the characters and graphics of the document, the orientation of the additional image acquired in step S34 described later is set.

  Based on the setting contents set in step S11 and step S12, a composite image to be printed on the recording paper is created (S13). Step S13 is an example of the synthesis unit of the present invention. The created composite image data is stored in the composite image data memory 83k (S14).

The composite image shown in FIG. 9 stored in the composite image data memory 83k is displayed by the display unit 42 (S15). It is determined whether or not the user inputs “print OK” through the keyboard unit 41 (S16). If there is no “print OK” input (S16: NO), the processing from step S12 is repeated, and if “print OK” is input (S16: YES), printing is executed and composition is performed. The image is printed on the recording paper (S17), and the main process is terminated.
(Character array direction detection processing)
Details of the character arrangement direction detection processing of the image forming apparatus 10 will be described with reference to FIG. FIG. 4 is a flowchart showing details of the character arrangement direction detection processing executed in step S10.

  In this character arrangement direction detection process, first, with respect to an image including characters and figures of a document stored in the document data memory 83c, a main scanning direction that is orthogonal to the recording sheet feeding direction and a recording sheet feeding direction. For each of the parallel scanning direction and the sub-scanning direction, a density distribution of an image including characters and graphics on the document is created (S20). Then, the periodicity of the created concentration distribution in each direction is detected (S21).

  Consider the density distribution in the A-line direction (sub-scanning direction) and the B-line direction (main scanning direction) for image data including characters and graphics in the document shown in FIG. FIG. 7 is an enlarged view of a part of the character group M1. For the characters arranged in the row direction as in the character group M1, the density distribution AD in the A-line direction is high in the portion where the characters are present, and the density is almost “0” between the lines. Further, the density distribution BD in the B-line direction is high in the portion where the character exists, and the density is almost “0” between the characters. For this reason, portions where the density is “0” between lines and between characters occur at regular intervals. Thereby, the periodicity of the concentration distribution is detected in the A-line direction and the B-line direction. The density distribution interval AD1 in the A line direction and the density distribution interval BD1 in the B line direction at which the density is “0” are stored in the density distribution data memory 83e. FIG. 8 is an enlarged view of a part of the character group M2. For the characters arranged in the column direction as in the character group M2, the density distribution AD in the A-line direction is high in the portion where the characters are present, and the density is almost “0” between the lines. Further, the density distribution BD in the B-line direction is high in the portion where the character exists, and the density is almost “0” between the characters. For this reason, the portions having the density “0” occur at regular intervals. Thereby, the periodicity of the concentration distribution is detected in the A-line direction and the B-line direction. The density distribution interval BD2 in the B line direction and the density distribution interval AD2 in the A line direction at which the density is “0” are stored in the density distribution data memory 83e. As for the graphic group M3, in the A-line direction and the B-line direction, the portion having the density “0” does not appear periodically, and the periodicity of the density distribution is not detected for the graphic group M3. In the present embodiment, the detection of the periodicity of the density distribution is performed in the A-line direction and the B-line direction orthogonal to each other over the entire area of the image forming area GR. Step S21 is an example of the character detection unit of the present invention.

  Various methods are conceivable as specific methods for detecting the density distribution AD in the A line direction and the density distribution BD in the B line direction shown in FIGS. 7 and 8, respectively. For example, in order to detect the density distribution AD, pixels to be printed for data stored in the document data memory 83c by a predetermined number of scanning lines in the A line direction corresponding to the width or height of one character. Pixels that are not printed are detected. The density distribution AD is detected by performing a logical sum calculation process on the detection result of the printing state of the pixels detected by the predetermined number of scanning lines. In order to detect the density distribution BD, the printing state of the pixels is detected by a predetermined number of scanning lines in the B-line direction, and a similar logical sum calculation process is executed.

  Based on the result of detecting whether or not the density distribution is periodic in step S21, it is determined whether or not a character exists (S22). That is, if it is detected that there is periodicity in the density distribution, it is determined that there is a character. When it is detected that there is no periodicity of the density distribution, it is determined that there is no character or a figure other than the character exists. If the presence of a character is determined (S22: YES), the character arrangement direction is detected. In FIG. 7, for the character group M1, a comparison is made between the interval AD1 of the density distribution AD in the A line direction and the interval BD1 of the density distribution BD in the B line direction stored in the density distribution data memory 83e. Since the interval AD1 of the density distribution AD in the A line direction is larger than the interval BD1 of the density distribution BD in the B line direction, the interval AD1 is not a character interval but a line interval. As a result, the character arrangement direction is detected as the B line direction in which the space BD1 as the character space appears, that is, the horizontal writing direction. On the other hand, in FIG. 8, for the character group M2, a comparison is made between the density distribution BD2 in the B-line direction and the distance AD2 of the density distribution AD in the A-line direction stored in the density distribution data memory 83e. Since the density distribution BD2 in the B line direction is larger than the interval AD2 of the density distribution AD in the A line direction, the interval BD2 is not a character interval but a line interval. As a result, the character arrangement direction is detected as the A-line direction in which the interval AD as the character interval appears, that is, the vertical writing direction (S23).

  In the actual detection process, since the periodicity of the density distribution is detected for the entire image forming region GR of the document, several tens to several hundreds of the main scanning direction and the sub-scanning direction are spread over the entire document. The periodicity of the density distribution is detected in the direction of about this number of lines.

  Due to the periodicity of the density distribution, the detected character arrangement direction is stored in the character arrangement direction data memory 83f for each character group (S24). In this way, the character arrangement direction is detected, and the character arrangement direction detection process ends. The character arrangement direction detection process is an example of a character arrangement direction detection unit of the present invention.

If it is determined in step S22 that the presence of a character is not detected (S22: NO), the arrangement direction detection process is not executed and the character arrangement direction detection process ends.
(Additional image orientation change processing)
Details of the additional image orientation changing process of the image forming apparatus 10 will be described with reference to FIG. FIG. 5 is a flowchart showing details of the additional image orientation changing process executed in step S11.

  In this additional image orientation changing process, it is first determined whether or not the image is an additional image to be added to a character (S30).

  If it is an additional image to be added to the character (S30: YES), it is determined whether or not the additional image is a hidden image (S31). In the present embodiment, the hidden image means, for example, an additional image having the transmittance “0%” set by the user and stored in the transmittance data memory 83d in step S9. Step S31 is an example of the hidden image determination unit of the present invention.

  If it is determined in step S31 that the image is not a hidden image (S31: NO), the additional image orientation data stored in the forward change data memory 83b and the character arrangement direction stored in the character arrangement direction data memory 83f Are compared to determine whether the orientation of the additional image is within a predetermined intersection angle range with respect to the character arrangement direction (S32). Step S32 is an example of the intersection determination unit of the present invention.

  If it is determined in step S32 that it is not within the predetermined crossing angle range (S32: NO), the orientation of the additional image is changed to a predetermined crossing direction (S33).

For example, a predetermined intersection angle range with relatively high character visibility is set to 40 degrees to 45 degrees. This intersection angle range is stored in the intersection angle range data memory 83g of the RAM 83. Assume that the orientation data of the additional image stored in the changed forward data memory 83b is orientation data tilted 5 degrees counterclockwise with respect to the main scanning direction. As shown in FIG. 6, since the character arrangement direction of the character group M1 stored in the character arrangement direction data memory 83f is 0 degrees with respect to the horizontal writing direction, that is, the main scanning direction, the intersection angle is 5 degrees. Since this intersection angle is outside the predetermined intersection angle range, the orientation data of the additional image is changed to be a direction rotated 45 degrees counterclockwise with respect to the character arrangement direction. Since the character arrangement direction of the character group M2 stored in the character arrangement direction data memory 83f is 90 degrees with respect to the vertical writing direction, that is, the main scanning direction, the intersection angle is 85 degrees. Since this intersection angle is outside the predetermined intersection angle range, the orientation data of the additional image is changed to be a direction rotated 45 degrees counterclockwise with respect to the character arrangement direction. In the present embodiment, the direction intersecting at a predetermined angle is a direction rotated 45 degrees counterclockwise with respect to the character arrangement direction. The direction intersecting at the predetermined angle is stored in the intersection angle direction data memory 83h.
Then, the direction of the changed additional image is stored in the post-change data memory 83i (S34). In this way, the direction in which the additional image is added is changed, and the additional image direction changing process ends. The additional image orientation changing process is an example of the orientation changing unit of the present invention.

  In step S30, if the image is not an additional image to be added to the character (S30: NO), the direction of the additional image is not changed, and the additional image orientation changing process is terminated. For example, as shown in FIG. 7, since the arrangement direction is not detected for the figure group M3, the direction of the additional image is not changed. In the present embodiment, the additional image is added in a state of being tilted 5 degrees counterclockwise.

  If it is determined in step S31 that the image is a hidden image (S31: YES), data relating to the character arrangement direction is read from the character arrangement direction data memory 83f, and the hidden image is read according to the data relating to the character arrangement direction. The direction of the additional image is changed to the character arrangement direction so as to cover the character (S35). For example, as shown in FIG. 6, the character arrangement direction of the character group M1 stored in the character arrangement direction data memory 83f is the main scanning direction, that is, the horizontal writing direction, so that the hidden image covers the character. The hidden image orientation data stored in the forward change data memory 83b is changed so as to be in the same direction as the character arrangement direction. Since the character arrangement direction of the character group M2 stored in the character arrangement direction data memory 83f is the sub-scanning direction, that is, the vertical writing direction, it is stored in the forward-change data memory 83b so that the hidden image covers the characters. The orientation data of the hidden image is changed so as to be in the same direction as the character arrangement direction.

  Then, the changed orientation of the hidden image is stored in the changed orientation data memory 83i (S36). Thus, the orientation of the hidden image is changed, and the additional image orientation changing process is completed.

  If it is determined in step S32 that the angle is within the predetermined crossing angle range (S32: YES), the orientation of the additional image is not changed, and the additional image orientation changing process ends.

  Although the present invention has been described based on the present embodiment, the present invention is not limited to the embodiment described above, and various improvements and modifications can be made without departing from the spirit of the present invention. It can be easily guessed.

  The additional image in the present embodiment includes a watermark, a so-called watermark image, and a hidden image.

  In the present exemplary embodiment, the image forming apparatus 10 including the main processing program has been described. For example, the main processing program is mounted on a personal computer, and the additional image created by the main processing program is combined with the characters. And it is good also as a structure which produces | generates a synthesized image.

  In this embodiment, the periodicity of the density distribution is detected in the horizontal writing direction and the vertical writing direction, but can also be detected in characters written in an oblique direction. For example, if the periodicity of the density distribution is not detected in each of the main scanning direction and the sub-scanning direction, the detection direction is rotated, and if the periodicity of the density distribution can be detected in an oblique direction, the direction is The character array direction. If the periodicity of the density distribution is still not detected, the graphic group is assumed.

  In the present embodiment, the predetermined crossing angle range is set to 40 degrees to 45 degrees. However, the present invention is not limited to this, and a configuration in which the user can arbitrarily set the crossing angle range according to the visibility of characters is also possible. good.

  In this embodiment, the orientation of the additional image is changed to a direction rotated 45 degrees counterclockwise with respect to the character arrangement direction. However, the present invention is not limited to this. The orientation of the additional image is most preferably changed in a direction rotated 90 degrees with respect to the character arrangement direction in order to improve the visibility of the characters. The reason is that the overlapping area between the additional image and the character is the smallest when it is rotated 90 degrees and intersected.

1 is a perspective view illustrating an external configuration of an image forming apparatus according to an embodiment of the present invention. 2 is a block diagram illustrating an electrical configuration of the image forming apparatus. FIG. 4 is a flowchart illustrating main processing of the image forming apparatus. 5 is a flowchart illustrating a character arrangement direction detection process of the image forming apparatus. 6 is a flowchart illustrating an additional image orientation changing process of the image forming apparatus. It is a figure which shows notionally the memory | storage content of the character data of a document, and graphic data in order to demonstrate a character arrangement direction detection process. It is a figure which shows notionally the storage content and density distribution of character data in order to demonstrate the density distribution of the character group M1 of a horizontal writing direction. It is a figure which shows notionally the storage content and density distribution of character data, in order to demonstrate the density distribution of the character group M2 of a vertical writing direction. It is a figure which shows the synthesized image by which the additional image and the character were synthesize | combined.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 20 Printer part 30 Scanner part 40 Keyboard part S10 Character arrangement direction detection process S11 Additional image direction change process GR Image formation area M1 Character group M3 Graphic group WM Additional image

Claims (8)

A character arrangement direction detector for detecting the arrangement direction of characters formed on the recording medium;
A direction changing unit that changes the direction of the additional image in a direction intersecting with the character arrangement direction detected by the character arrangement direction detection unit;
A synthesis unit that generates a synthesized image by adding an additional image whose orientation has been changed by the orientation changing unit to characters formed on a recording medium, and
The direction changing unit is
An intersection determination unit that determines whether or not an angle at which the direction of the additional image and the character arrangement direction intersect is a predetermined angle intersection range;
When the intersection determination unit determines that it is within the predetermined intersection angle range, the direction of the additional image is not changed, and when it is determined that the additional image is outside the predetermined intersection angle range, the direction of the additional image is set to the direction of the additional image. And the character arrangement direction are changed so as to intersect at a predetermined angle.   The image processing apparatus according to claim 1, wherein the synthesizing unit generates a synthesized image by adding a plurality of the additional images in a direction intersecting with the character arrangement direction detected by the character arrangement direction detection unit. . The character arrangement direction detector
A character detection unit for detecting the presence or absence of characters from an image including characters formed on a recording medium;
The image processing apparatus according to claim 1, wherein when the character detection unit detects the presence of a character, the image detection device detects an arrangement direction of the detected character.   The orientation changing unit changes only the orientation of the additional image added to the character detected by the character detection unit to a direction intersecting the character arrangement direction, and is added to an image other than the detected character. The image processing apparatus according to claim 3, wherein the orientation of the additional image is not changed.   5. The image processing according to claim 1, wherein the orientation changing unit changes the orientation of the additional image to 90 degrees with respect to an arrangement direction of characters formed on the recording medium. apparatus. The direction changing unit is
A hidden image determination unit that determines whether the additional image is a hidden image intended to hide characters;
6. The image according to claim 1, wherein when the hidden image determination unit determines that the image is a hidden image, the direction of the additional image is changed to the same direction as the detected character arrangement direction. Processing equipment. A character arrangement direction detector for detecting the arrangement direction of characters formed on the recording medium;
A direction changing unit that changes the direction of the additional image in a direction intersecting with the character arrangement direction detected by the character arrangement direction detection unit;
A compositing unit that generates a composite image by adding an additional image whose orientation has been changed by the orientation changing unit to characters formed on the recording medium;
An image forming unit that forms a composite image generated by the combining unit on a recording medium ;
The direction changing unit is
An intersection determination unit that determines whether or not an angle at which the direction of the additional image and the character arrangement direction intersect is a predetermined angle intersection range;
When the intersection determination unit determines that it is within the predetermined intersection angle range, the direction of the additional image is not changed, and when it is determined that the additional image is outside the predetermined intersection angle range, the direction of the additional image is set to the direction of the additional image. And the character arrangement direction are changed so as to intersect at a predetermined angle. A character arrangement direction detection function for detecting the arrangement direction of characters formed on the recording medium;
A direction changing function for changing the direction of the additional image in a direction intersecting with the character arrangement direction detected by the character arrangement direction detection function;
An image processing program for realizing , by a computer , a composition function for generating a composite image by adding an additional image whose orientation is changed by the orientation change function to characters formed on a recording medium ,
The direction changing function is
Having an intersection determination function for determining whether or not the angle at which the direction of the additional image intersects the character arrangement direction is within a predetermined angle intersection range;
When it is determined that the intersection determination function is within a predetermined intersection angle range, the orientation of the additional image is not changed, and when it is determined that it is outside the predetermined intersection angle range, the orientation of the additional image is changed to the orientation of the additional image. And the character arrangement direction are changed so as to intersect at a predetermined angle.

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