JP2021118428A - Image processing apparatus, image reading device, image forming apparatus, and image processing method - Google Patents

Abstract

To provide an image processing apparatus, an image reading device, an image forming apparatus, and an image processing method that can reduce a situation where a fluorescent portion written with a color fluorescent writing instrument becomes pale and thereby can make the fluorescent portion conspicuous.SOLUTION: An image processing apparatus, an image reading device, an image forming apparatus, and an image processing method that process image data of a document read by an image sensor unit create the frequency distribution of gradations based on the image data read by the image sensor unit, determine the gradation distribution of the grounding of the document where the gradation frequency is concentrated most in the frequency distribution, determine a first gradation distribution where the gradation distribution is concentrated on a brighter side than the gradation distribution of the grounding in the frequency distribution, and when determining that the first gradation distribution is present in the frequency distribution, perform predetermined first correction processing on the image data.SELECTED DRAWING: Figure 8

Description

The present invention relates to an image processing device for processing image data of a document read by an image sensor unit, an image reading device and a copying machine, an image forming device such as a multifunction device, and an image processing method.

In an image processing device that processes image data of a document read by an image sensor unit, for example, an image sensor is a document in which a user writes a desired part (marked on characters) with a color fluorescent writing tool such as a fluorescent marker pen. When scanning with a unit, when the scanned image data is output to the output device (displayed on the display device or printed on the image forming device body), the output document image is fluorescently written with a color fluorescent writing tool. The part may be faint (faint or dull) unlike the image of the original manuscript. This is particularly remarkable when the image sensor unit is a close contact type image sensor unit used in the close contact optical system of the image reading device.

Therefore, it is desired to reduce the thinning of the fluorescent portion written by the color fluorescent writing instrument and to make the fluorescent portion stand out.

Regarding this point, in Patent Document 1, in a manuscript in which a character (marked character) drawn on the character by a highlighter pen or the like exists, the contrast difference between the character and the background thereof is small. Therefore, since the characters are difficult to read, it is disclosed that the user edits the scanned image in which the background cover characters (area to be examined) exist (editing processing such as darkening the characters or skipping the background). (See paragraphs [0084], [0085]).

Japanese Unexamined Patent Publication No. 2015-138896

However, the invention described in Patent Document 1 is not designed to reduce the thinning of the fluorescent portion written by the color fluorescent writing instrument.

Therefore, the present invention can reduce the thinning of the fluorescent portion written by the color fluorescent writing tool, thereby making the fluorescent portion stand out, as well as an image processing device, an image reading device, and an image forming device. It is an object of the present invention to provide an image processing method.

The present invention provides the following image processing device, image reading device, image forming device, and image processing method in order to solve the above problems.

(1) Image Reading Device The image reading device according to the present invention is an image processing device that processes image data of a document read by an image sensor unit, and gradation is based on the image data read by the image sensor unit. From the frequency distribution generation means for generating the frequency distribution with respect to the frequency distribution, the background determination means for determining the gradation distribution of the background of the manuscript in which the gradation distribution is most concentrated in the frequency distribution, and the gradation distribution of the background in the frequency distribution. With respect to the first determination means for determining the first gradation distribution in which the gradation distribution is concentrated on the bright side, and the image data when it is determined that the first gradation distribution exists in the frequency distribution. It is characterized by comprising a first correction processing means for performing a predetermined first correction processing.

(2) Image Reading Device The image reading device according to the present invention is characterized by including the image processing device according to the present invention.

(3) Image Forming Device The image processing device according to the present invention or the image reading device according to the present invention is provided.

(4) Image Reading Method The image reading method according to the present invention is an image processing method for processing image data of a document read by an image sensor unit, and gradation is based on the image data read by the image sensor unit. A generation step for generating a frequency distribution with respect to the image, a background determination step for determining the gradation distribution of the background of the document in which the gradation distribution is most concentrated in the frequency distribution, and a background determination step in which the frequency distribution is brighter than the gradation distribution of the background. When the first determination step for determining the first gradation distribution in which the gradation distribution is concentrated on the side and the determination that the first gradation distribution exists in the frequency distribution, a predetermined value is provided for the image data. It is characterized by including a first correction processing step for performing the first correction processing.

According to the present invention, it is possible to reduce the thinning of the fluorescent portion written by the color fluorescent writing instrument, which makes it possible to make the fluorescent portion stand out.

It is a schematic perspective view which shows the appearance of the image forming apparatus provided with the image reading apparatus which concerns on embodiment of this invention. It is the schematic front view which shows the image forming apparatus shown in FIG. 1 perspectively. It is the schematic front view which shows the image reading device part in the image forming apparatus shown in FIG. 1 perspectively. It is a system block diagram of the control system in the image reading apparatus which concerns on this embodiment. FIG. 5 is a plan view schematically showing an image of a manuscript in which a mark is marked on paper with a highlighter pen of each color and a non-fluorescent marker pen of each color. FIG. 5 is a plan view showing an output result obtained by reading the document shown in FIG. 5 with a conventional image processing device and outputting it to an output device (display device or image forming device main body). FIG. 5 is a plan view showing that the portion marked with the highlighter pen in the document shown in FIG. 5 is brighter than the base of the document. It is a plan view showing an image of a manuscript in which a mark is marked on a character written on paper with a yellow highlighter pen, and a histogram showing a graph of a frequency distribution generated based on the image data. It is a plan view showing an image of a manuscript marked with a yellow highlighter pen, and a histogram showing a graph of a frequency distribution generated based on the image data. It is a plan view showing an image of a manuscript marked with a red highlighter pen, and a histogram showing a graph of a frequency distribution generated based on the image data. It is a plan view showing an image of a manuscript marked with an orange highlighter pen, and a histogram showing a graph of a frequency distribution generated based on the image data. This is a histogram showing a graph of the frequency distribution generated based on the image data of a manuscript written on paper on which characters are written with a non-fluorescent red ballpoint pen. It is a histogram showing the frequency distribution generated based on the image data of the manuscript written on the paper on which the characters are written with a non-fluorescent blue ballpoint pen. It is a plan view which shows the image of the manuscript of a photograph, and the histogram which represented the frequency distribution generated based on the image data by a graph. It is a flowchart which shows the first half part of the example of the image processing which concerns on this embodiment. It is a flowchart which shows the latter half part of the example of the image processing which concerns on this embodiment.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In the following description, the same parts are designated by the same reference numerals. Their names and functions are the same. Therefore, the detailed description of them will not be repeated.

[Image forming device]
FIG. 1 is a schematic perspective view showing the appearance of an image forming apparatus 100 provided with an image reading apparatus 200 according to an embodiment of the present invention. FIG. 2 is a schematic front view showing the image forming apparatus 100 shown in FIG. 1 perspectively. Further, FIG. 3 is a schematic front view of the image reading device 200 portion of the image forming device 100 shown in FIG. 1 which is seen through. In FIGS. 1 to 3, reference numeral X indicates a main scanning direction (depth direction), reference numeral Y indicates a sub-scanning direction (horizontal direction), and reference numeral Z indicates a vertical direction. There is.

The image forming apparatus 100 includes an image reading device 200 and an image forming apparatus main body 110, and the image forming apparatus main body 110 uses the image forming apparatus main body 110 to record sheets P such as paper based on the image data of the document G read by the image reading device 200. Image formation is performed.

The image forming apparatus 100 is an electrophotographic type, and is an intermediate transfer type color multifunction device capable of forming a full-color image. The image forming apparatus 100 is a so-called tandem type in which a plurality of electrostatic latent image carriers (specifically, photoconductors 2a to 2d) on which toner images are formed are arranged side by side in a predetermined direction (sub-scanning direction Y). It is a color image forming apparatus of. The image forming apparatus 100 may be another color image forming apparatus. Further, in the present embodiment, the image forming apparatus 100 is a color image forming apparatus, but may be a monochrome image forming apparatus.

As shown in FIG. 2, the image forming apparatus main body 110 includes an image forming unit 101 that forms (prints) an image and a sheet conveying unit 102 that conveys the recording sheet P.

The image forming apparatus 100 includes four sets of image forming stations pa to pd, an exposure apparatus 4, a primary transfer apparatus 6a to 6d, an intermediate transfer belt 7, a belt cleaning apparatus 9, a secondary transfer apparatus 11, a fixing apparatus 12, and an image forming apparatus 100. A paper feeding device 13 for accommodating a recording sheet P such as a recording paper is provided.

An image reading device 200 is provided above the image forming device main body 110. The image reading device 200 includes an image reading unit 210 for reading an image of the document G and a document transporting unit 220 (specifically, an automatic document feeding device) for transporting the document G, and the document reading glass 213 (an example of a transparent body). The image of the original G conveyed by the original transfer unit 220 via) is read by the image reading unit 210, or the image of the original G placed on the original mounting glass 212 acting as the original placing table is read. It is read by unit 210 and output as image data of the read original G. The image data of the document G read by the image reader 200 is sent to the image forming apparatus main body 110, or the image data from an external device is sent to the image forming apparatus main body 110 and converted into image data in the image forming apparatus main body 110. The image formed based on this is recorded on the recording sheet P.

In the image forming unit 101, charging devices 3a to 3d, developing devices 5a to 5d, and photoconductor cleaning devices 8a to 8d are arranged in this order around the photoconductors 2a to 2d, respectively.

In the image forming apparatus 100, when the image is formed, the surfaces of the photoconductors 2a to 2d uniformly charged by the charging apparatus 3a to 3d are laser-exposed by the exposure apparatus 4 according to the image data (image information). Electrostatic latent images are formed on the photoconductors 2a to 2d, respectively. The electrostatic latent images formed on the photoconductors 2a to 2d are developed by the developing devices 5a to 5d and visualized in toner images, respectively. The toner images on the photoconductors 2a to 2d are transferred by the primary transfer devices 6a to 6d on the intermediate transfer belt 7 stretched on the driving roller 7a and the driven roller 7b. The toner image on the intermediate transfer belt 7 is conveyed to the secondary transfer device 11 by the intermediate transfer belt 7 rotated in the predetermined rotation direction E. On the other hand, the recording sheet P pulled out from the paper feed roller 13a of the paper feed device 13 toward the transfer path S is conveyed to the resist roller 15 by the transfer roller 14 through the transfer path S conveyed by the sheet transfer unit 102. NS. At this time, the resist roller 15 has stopped rotating and starts rotating at a predetermined timing. The recording sheet P is conveyed to the secondary transfer device 11 in synchronization with the toner image on the intermediate transfer belt 7 by the rotation of the resist roller 15. The toner image conveyed by the intermediate transfer belt 7 is transferred to the recording sheet P conveyed by the resist roller 15 by the secondary transfer roller 11a of the secondary transfer device 11. The toner image transferred onto the recording sheet P is conveyed to the fixing device 12, heated and pressurized by the fixing roller 12a and the pressure roller 12b of the fixing device 12, and fused onto the recording sheet P. The fixing-processed recording sheet P is discharged to the outside of the image forming apparatus main body 110 by the discharge roller 16 and placed on the discharge tray 17.

Further, when the image is formed not only on the front surface of the recording sheet P but also on the back surface, the fixing-processed recording sheet P is conveyed in the reverse direction to the reversing path Sr by the reverse rotation of the discharge roller 16. The recording sheet P conveyed by the conveying roller 14 in the inversion path Sr is inverted and guided to the resist roller 15 again, and a toner image is formed and fixed on the back surface in the same manner as the front surface. After that, the recording sheet P is discharged to the outside of the image forming apparatus main body 110 by the discharge roller 16 and placed on the discharge tray 17.

[Image reader]
As shown in FIGS. 2 and 3, the image reading device 200 includes an image sensor unit 240 (color image sensor unit) that reads an image of the document G.

In the present embodiment, the image reading device 200 is configured to fix the document G by the document fixing method and read the image of the document G, while moving the document G by the document moving method to read the image of the document G. ing. Specifically, the image reading device 200 includes a document fixed scanning configuration and a document moving scanning configuration. In the original fixed scanning configuration, the original G is placed on the original mounting glass 212 while the first scanning body 211 is moved to one side Y1 in the sub-scanning direction Y while the original G is placed on the original mounting glass 212. The image of the document G is scanned and read in the main scanning direction X. In the document moving scanning configuration, the document transporting unit 220 transports the document G in the transporting direction C (secondary scanning direction) while the first scanning body 211 is stopped at a predetermined scanning position Q, and is placed on the document scanning glass 213. The image of the conveyed document G is scanned and read in the main scanning direction X.

The image reading unit 210 includes a first scanning body 211, a document mounting glass 212, a document reading glass 213, a second scanning body 214, a condenser lens 215, a reduced image sensor unit 216 (an example of the image sensor unit 240), and these. It is provided with a frame body 217 for accommodating the constituent members of the above.

The first scanning body 211 is provided below the document mounting glass 212 and the document reading glass 213 so as to be reciprocally movable with respect to the frame body 217 along the sub-scanning direction Y, and is provided by an optical system drive unit (not shown). By being driven, it reciprocates in the sub-scanning direction Y. The first scanning body 211 includes a light source 211a that irradiates the document G with light, and a first mirror 211b that guides the reflected light Lr from the document G to the second scanning body 214, and constitutes a light source unit. .. Both the document mounting glass 212 and the document scanning glass 213 have an image scanning surface that serves as a scanning reference surface for the document G.

The second scanning body 214 includes a second mirror 214a, a third mirror 214b, and a support member (not shown), and constitutes a mirror unit. The support member in the second scanning body 214 supports the second mirror 214a so as to reflect the light from the first mirror 211b in the first scanning body 211 and guide it to the third mirror 214b. Further, the support member in the second scanning body 214 supports the third mirror 214b so as to reflect the light from the second mirror 214a and guide it to the condenser lens 215.

The condenser lens 215 concentrates the light from the third mirror 214b in the second scanning body 214 on the light receiving surface 216a of the reduced image sensor unit 216. The reduced image sensor unit 216 converts the light from the condenser lens 215 (image light of the document G) into an electric signal as image data. The reduced image sensor unit 216 includes an image sensor 216b such as a charge-coupled device (CCD) and a complementary metal oxide semiconductor (CMOS). The image sensor 216b is provided with a color filter. The color filter is a color selection filter formed corresponding to each pixel. Generally, the composition of the color filter includes a primary color filter [red (R) / green (G) / blue (B) filter] and a complementary color filter [cyan (C) / magenta (M) / yellow (Y) / green. (G) filter], and these can be used properly depending on the application of the image pickup element. The primary color filter is advantageous for color reproducibility, and the complementary color filter is advantageous for resolution.

Further, the optical system drive unit in the image reading device 200 moves the first scanning body 211 to one side Y1 in the sub-scanning direction Y at a constant speed, and moves the second scanning body 214 to the moving speed of the first scanning body 211. It is also configured to move to one side Y1 in the sub-scanning direction Y at a moving speed of 1/2 of that.

The document transport unit 220 is arranged on the upper surface of the image reading unit 210. The document transport unit 220 is rotatably provided around the pivot axis along the sub-scanning direction Y on the back side (opposite the operation side), which is one side in the main scanning direction X, with respect to the image reading unit 210. Has been done. The document transport unit 220 is opened and closed from the front side (operation side) so that the document mounting glass 212 in the image reading unit 210 is opened and closed. The lower surface of the document transport unit 220 also serves as a document holding member that presses the document G placed on the document mounting glass 212 from above.

Specifically, the document transport section 220 automatically transports the document G, and the document loading tray 221 and the supply roller 222, the sheet transfer path W2 (document transfer path), the first transfer roller 223, and the resist roller. 224, a second transport roller 225, a third transport roller 226, a discharge roller 227, and a document discharge tray 228 are provided.

The document loading tray 221 is for mounting one or a plurality of documents G, and is arranged on the upper part of the image reading device 200. The supply roller 222 pulls out the original documents G placed on the original document placing tray 221 one by one. The supply roller 222 is composed of a lead roller 222a (pickup roller), a feed roller 222b, and a separation member 222c (separation roller in this example) such as a separation roller and a separation pad. The calling roller 222a sends the document G placed on the document loading tray 221 from the document loading tray 221 into the sheet transport path W2 along the transport direction C of the document G. The feed roller 222b further transports the document G sent by the lead roller 222a to the downstream side in the transport direction C while sandwiching the document G together with the separating member 222c. The separation member 222c separates the document G so that the document G to be conveyed between the feed roller 222b and the feed roller 222b is one sheet in a state of facing the feed roller 222b.

The sheet transport path W2 guides the document G pulled out by the supply roller 222 to the discharge side (below the document loading tray 221) via the document reading glass 213. The first transfer roller 223, the resist roller 224, the second transfer roller 225, the third transfer roller 226, and the discharge roller 227 are provided on the sheet transfer path W2. The first transport roller 223 transports the document G pulled out by the supply roller 222 to the resist roller 224. The resist roller 224 temporarily stops the document G transported to the sheet transport path W2, and restarts the transfer of the document G at a predetermined reading timing. The resist roller 224 conveys the document G conveyed by the first transfer roller 223 onto the document reading glass 213. The second transfer roller 225 conveys the document G conveyed from the document reading glass 213 toward the third transfer roller 226. The third transfer roller 226 conveys the document G conveyed by the second transfer roller 225 toward the discharge roller 227. The ejection roller 227 ejects the document G conveyed from the third conveying roller 226 toward the document ejection tray 228. The document ejection tray 228 is arranged below the document loading tray 221 and mounts the document G ejected by the ejection roller 227.

In this example, the image reading device 200 further includes a close contact type image sensor unit 229 (another example of the image sensor unit 240). The image reading device 200 reads the image on the other side (back surface) of the document G by the close contact type image sensor unit 229 in the document moving reading operation.

The close contact type image sensor unit 229 converts the image light from the back surface of the document G into an electric signal as image data. The close contact type image sensor unit 229 includes a light source 229a (LED) that irradiates the document G with light, a 1x coupling lens array 229b that forms an image of the image light reflected from the document G at the same magnification, and a 1x coupling system. It includes a close contact image sensor (CIS: Contact Image Sensor) 229c that receives image light from the lens array 229b. The close contact type image sensor unit 229 has a long shape in the main scanning direction X. The close contact type image sensor unit 229 is provided on the downstream side of the third transport roller 226 on the sheet transport path W2 and on the upstream side of the discharge roller 227 in the transport direction C of the document G. In the close contact type image sensor unit 229, for example, the wavelength light corresponding to the primary color light (red, green, blue) emitted from the light source 229a can be sequentially turned on to read the image of the document G. In the configuration of the close contact type image sensor unit 229, the number of readings is three, but the configuration for reading the image of the document G can be simplified.

In the image reading device 200 described above, when the image of the document G is read by the document fixing method, the light source 211a of the first scanning body 211 is placed on the document G placed on the document mounting glass 212 via the document mounting glass 212. The image of the original G is scanned by moving the first scanning body 211 to one side Y1 in the sub-scanning direction Y at a constant speed while irradiating the incident light Li from the light source. Further, the second scanning body 214 is moved to one side Y1 in the sub-scanning direction Y at a moving speed of 1/2 of the moving speed of the first scanning body 211. At this time, the reflected light Lr reflected from the document G is received by the light irradiation from the light source 211a in the first scanning body 211 via the document mounting glass 212. The reflected light Lr (image light) is reflected by the first mirror 211b provided on the first scanning body 211, and then the optical path is converted by the second mirror 214a and the third mirror 214b of the second scanning body 214, and the condensing lens. An image is formed on the light receiving surface 216a of the reduced image sensor unit 216 via the 215, and the image light of the document G is read here and converted into electrical image data.

On the other hand, when the image of the original G is read by the original moving method, the original scanning unit 220 keeps the first scanning body 211 stationary at the reading position Q of the original reading glass 213, and the original transfer unit 220 causes the original G to be read by the image reading surface of the original reading glass 213. It is conveyed to one side Y1 in the sub-scanning direction Y so that the document G passes over. Specifically, the document G placed on the document loading tray 221 is conveyed between the feed roller 222b and the separation member 222c by the lead roller 222a, where the document G is separated and the feed roller 222b is rotationally driven. By being carried, they are conveyed one by one. Then, the document G conveyed by the feed roller 222b is guided by the sheet transfer path W2 and supplied one by one toward the first transfer roller 223, and is conveyed toward the resist roller 224 by the first transfer roller 223. Will be done. The original G, which has been conveyed to the resist roller 224, is conveyed so that the tips of the original G are aligned by the resist roller 224 and the image surface is brought into close contact with the image reading surface of the original reading glass 213 at a predetermined reading timing.

Further, the first scanning body in a state of being stopped at the reading position Q below the document scanning glass 213 via the document scanning glass 213 on one surface (surface) of the document G passing over the image scanning surface of the document scanning glass 213. The incident light Li is irradiated from 211. At this time, the reflected light Lr reflected from the document G is received by the light irradiation from the light source 211a in the first scanning body 211 via the document reading glass 213. The reflected light Lr (image light) is reflected by the first mirror 211b as in the above-mentioned document fixing method, then optical path is converted by the second mirror 214a and the third mirror 214b, and the reduced image is transmitted through the condenser lens 215. An image is formed on the light receiving surface 216a of the sensor unit 216, and an image of one surface of the document G is read and converted into electrical image data. After that, the document G that has passed through the document reading glass 213 is conveyed to the discharge roller 227 via the second transfer roller 225 and the third transfer roller 226. At this time, when reading the image of the other side (back surface) of the document G, the close contact type image sensor unit 229 reads the image of the other side of the document G. Then, the document G that has passed through the close contact type image sensor unit 229 is ejected toward the document ejection tray 228 by the ejection roller 227 and placed on the document ejection tray 228.

Further, the image reading device 200 is provided with an operation unit 230 (see FIG. 1) at an upper portion on the operation side of the image forming device main body 110. The operation unit 230 is provided with a display device 231 (see FIG. 1).

(Control unit)
FIG. 4 is a system block diagram of the control system in the image reading device 200 according to the present embodiment. The image reading device 200 further includes an image processing device 250. The image processing device 250 processes the image data (red image data, green image data, and blue image data) of the document G read by the image sensor unit 240 (color image sensor unit). The image processing device 250 includes a control unit 251.

The control unit 251 includes a processing unit 251a composed of a microcomputer such as a CPU, and a storage unit 251b including a non-volatile memory such as a ROM and a volatile memory such as a RAM. The control unit 251 controls the operation of various components by loading the control program stored in advance in the ROM of the storage unit 251b into the RAM of the storage unit 251b and executing the processing unit 251a.

The image sensor unit 240 (reduced image sensor unit 216 and close contact type image sensor unit 229) is connected to the input system of the control unit 251. As a result, the control unit 251 can perform image processing on the image data received from the image sensor unit 240 (216, 229). Further, the display device 231 and the image forming device main body 110 are connected to the output system of the control unit 251. As a result, the control unit 251 can transmit the image processed image data to the display device 231 and the image forming device main body 110.

By the way, the conventional image processing apparatus has the following inconveniences. FIG. 5 is a plan view schematically showing an image of a manuscript G in which a mark MK is marked on paper with a highlighter pen of each color and a non-fluorescent marker pen of each color. FIG. 6 is a plan view showing an output result in which the document G shown in FIG. 5 is read by a conventional image processing device and output to an output device (display device or image forming device main body).

For example, manuscript G (see FIG. 5) in which the user writes a desired location with a color fluorescent writing tool such as a fluorescent marker pen and / or a color non-fluorescent writing tool such as a non-fluorescent non-fluorescent marker pen. ) Is read by the image sensor unit, and when the read image data is output to the output device (displayed on the display device or printed on the image forming device main body), the output document G is as shown in FIG. In the image IM of, the fluorescent portion written by the color fluorescent writing tool and / or the non-fluorescent portion written by the color non-fluorescent writing tool (non-fluorescent portion) is different from the image of the original manuscript G (see FIG. 5). , May become thin (faint or dull). These things become particularly remarkable when the image sensor unit is a close contact type image sensor unit used in the close contact optical system of the image reading device. The degree of thinning of the non-fluorescent portion written by the color non-fluorescent writing instrument is smaller than the degree of thinning of the fluorescent portion written by the color fluorescent writing instrument.

FIG. 7 is a plan view showing that the portion of the document G shown in FIG. 5 in which the mark MK is marked with the highlighter pen is brighter than the base BG of the document G. FIG. 8 is a plan view showing an image IM of a manuscript G in which a mark MK is marked on a character CR written on paper with a yellow fluorescent marker pen, and a histogram showing a frequency distribution generated based on the image data. Is. 9 to 11 are a plan view showing the image IM of the manuscript G on which the mark MK is marked with the yellow fluorescent marker pen, the red fluorescent marker pen, and the orange fluorescent marker pen, respectively, and the frequencies generated based on the image data. This is a histogram showing the distribution in a graph.

As shown in FIG. 7, the fluorescent portion HL marked with the mark MK with the fluorescent marker pen may be brighter than the base BG.

As shown in FIGS. 8 to 11, according to the findings of the present inventor, it was generated based on the image data (red image data, green image data, blue image data) read by the image sensor unit 240. In the frequency distribution (red frequency distribution, green frequency distribution, blue frequency distribution) with respect to gradation (brightness), the gradation distribution α1 that is most concentrated beyond a predetermined degree of concentration is [usually the bright side (usually bright side (usually)). Is white) within a predetermined gradation region β], this concentrated gradation distribution α1 can be regarded as the background BG (see FIG. 7) of the document G. Then, if there is a gradation distribution α2 concentrated on the side brighter than the gradation distribution α1 of the background BG of the document G, the concentrated gradation distribution α2 is written with a color fluorescent writing instrument such as a highlighter pen ( It can be regarded as the marked) fluorescent portion HL (see FIG. 7).

In this regard, the control unit 251 includes a frequency distribution generation means P1, a base determination means P2, a first determination means P3, and a first correction processing means P4, as shown in FIG. The control unit 251 includes a frequency distribution generation step corresponding to the frequency distribution generation means P1, a background determination step corresponding to the background determination means P2, a first determination step corresponding to the first determination means P3, and a first correction processing means. It functions as a means including the first correction processing step corresponding to P4.

The frequency distribution generation means P1 has a frequency distribution (red frequency) with respect to gradation based on image data (red image data, green image data, and blue image data) read by the image sensor unit 240 (color image sensor unit). Generate (generate each) a distribution, a green frequency distribution, and a blue frequency distribution. Specifically, the frequency distribution generation means P1 quantizes the brightness of each pixel of the image data into a plurality of gradations (for example, 0 to 255), and generates a frequency distribution with respect to the quantized gradation.

The background determination means P2 determines the gradation distribution α1 (α1r, α1g, α1b) of the background BG of the manuscript G in which the gradation distribution is most concentrated in the frequency distribution (red frequency distribution, green frequency distribution, and blue frequency distribution). Judgment (each judgment). Specifically, the background determination means P2 sets "dispersion" and / or "standard deviation" in a predetermined gradation region β (general gradation region that can be regarded as the background BG of the original G, for example, 200 to 255). When the degree of concentration of the frequency distribution is larger than the degree of concentration, it is determined that the gradation distribution α1 (α1r, α1g, α1b) of the base BG of the document G is used.

The first determination means P3 is brighter than the gradation distribution α1 (α1r, α1g, α1b) of the base BG in the frequency distribution (at least one frequency distribution of the red frequency distribution, the green frequency distribution, and the blue frequency distribution). The first gradation distribution α2 (α2g, α2r, α2r) in which the gradation distribution is concentrated on the side is determined (determined respectively). Specifically, the first determination means P3 uses "dispersion" and / or "standard deviation" in the gradation region γ on the side brighter than the gradation distribution α1 (α1r, α1g, α1b) of the base BG. When the degree of concentration of the frequency distribution is larger than the predetermined degree of concentration (when the degree of dispersion is smaller than the degree of dispersion of the predetermined degree), it is determined that the first gradation distribution α2 (α2g, α2r, α2r). In the yellow highlighter pen, the first gradation distribution α2g exists in the green frequency distribution, and in the red highlighter pen and the orange highlighter pen, the first gradation distribution α2r, α2r exists in the red frequency distribution. ..

The first correction processing means P4 has a first gradation distribution α2 (α2g, α2r, α2r) in the frequency distribution (at least one frequency distribution of the red frequency distribution, the green frequency distribution, and the blue frequency distribution). When it is determined that the image data (red image data, green image data, and blue image data) is determined to be so, a predetermined first correction process (sharpening process) is performed on the image data (red image data, green image data, and blue image data). Here, the first correction process is a process for clarifying an image portion corresponding to the first gradation distribution α2 (α2g, α2r, α2r), and exemplifies a process for emphasizing a change in gradation. can. The details of the first correction process will be described in detail. The first correction process may be performed on the entire image data, or the image area to be corrected (fluorescent portion HL) may be separated into areas and the image area to be corrected (fluorescent portion HL) should be corrected. ) May be corrected.

According to the present embodiment, the frequency distribution (at least one of the red frequency distribution, the green frequency distribution, and the blue frequency distribution) is higher than the gradation distribution α1 (α1r, α1g, α1b) of the base BG. Since the first gradation distribution α2 (α2g, α2r, α2r) in which the gradation distribution is concentrated on the bright side is determined, the image data (red image data, green) read by the image sensor unit 240 (216,229). The fluorescent portion HL written by the color fluorescent writing tool can be recognized in the image data and the blue image data). Then, when it is determined that the first gradation distribution α2 (α2g, α2r, α2r) exists in the frequency distribution, the image data (red image data, green image data, and blue image data) is determined in the first correction process. Since the first correction process is performed on the image (color image) of the original G output to the output device (display device 231 or image forming device main body 110), the fluorescent portion HL written by the color fluorescent writing tool is thin. It is possible to reduce becoming (faint or dull). In addition, reproducibility (color reproducibility) can be improved. This makes it possible to make the fluorescent portion HL written by the color fluorescent writing instrument stand out. This is particularly effective when the image sensor unit 240 is the close contact type image sensor unit 229 used in the close contact optical system of the image reading device 200.

(First Embodiment)
12 and 13 are histograms graphing the frequency distribution generated based on the image data of the manuscript G written on the paper on which the character CR is written with a non-fluorescent red ballpoint pen and a blue ballpoint pen, respectively.

As shown in FIGS. 12 and 13, according to the findings of the present inventor, it was generated based on the image data (red image data, green image data, and blue image data) read by the image sensor unit 240. In the frequency distribution for gradation (red frequency distribution, green frequency distribution, blue frequency distribution), the floor that is darker than the gradation distribution of the background BG of the original G and exceeds the predetermined concentration degree and is most concentrated. If there is a frequency distribution α3, this concentrated gradation distribution α3 can be regarded as the character CR of the manuscript G. Then, if there is a gradation distribution α4 concentrated between the gradation distribution α1 of the background BG of the document G and the gradation distribution α1 of the character CR, the concentrated gradation distribution α4 is used as a color non-fluorescent writing instrument. It can be regarded as the non-fluorescent portion NL written in. The mark MK marked with the highlighter pen shown in FIG. 8 also has a gradation distribution α4 concentrated between the gradation distribution α1 of the base BG of the original G and the gradation distribution α1 of the character CR, and is not present. Fluorescent portion NL is included.

In this regard, the control unit 251 further includes character determination means P5, a second determination means P6, and a second correction processing means P7, as shown in FIG. The control unit 251 is a means including a character determination step corresponding to the character determination means P5, a second determination step corresponding to the second determination means P6, and a second correction processing step corresponding to the second correction processing means P7. Functions as.

In the character determination means P5, the gradation distribution is most concentrated on the darker side than the gradation distribution α1 (α1r, α1g, α1b) of the base BG in the frequency distribution (red frequency distribution, green frequency distribution, and blue frequency distribution). The gradation distribution α3 (α3r, α3g, α3b) of the character CR of the original manuscript G is determined (determined respectively). Specifically, the character determination means P5 uses "dispersion" and / or "standard deviation" in the gradation region δ on the darker side than the gradation distribution α1 (α1r, α1g, α1b) of the background BG. When the degree of concentration of the distribution is larger than the degree of concentration of a predetermined degree, it is determined that the gradation distribution α3 (α3r, α3g, α3b) of the character CR.

The second determination means P6 has a gradation distribution α1 (α1r, α1g, α1b) of the base BG and a character CR in the frequency distribution (at least one frequency distribution of the red frequency distribution, the green frequency distribution, and the blue frequency distribution). The second gradation distribution α4 [(α4g, α4b), (α4r, α4b)] in which the gradation distribution is concentrated with the gradation distribution α3 (α3r, α3g, α3b) of Specifically, the second determination means P6 is in the gradation region φ between the gradation distribution α1 (α1r, α1g, α1b) of the base BG and the gradation distribution α3 (α3r, α3g, α3b) of the character CR. When the degree of concentration of the frequency distribution is greater than the predetermined degree of concentration using "variance" and / or "standard deviation" (when the degree of dispersion is smaller than the predetermined degree of dispersion), the second gradation distribution α4 [ (Α4g, α4b), (α4r, α4g)]. The red ballpoint pen has the second gradation distributions α4g and α4b in the green and blue frequency distributions, and the blue ballpoint pen has the second gradation distributions α4r and α4g in the red and blue frequency distributions.

The second correction processing means P7 determines that the first gradation distribution α2 does not exist in the frequency distribution (in any of the frequency distributions of the red frequency distribution, the green frequency distribution, and the blue frequency distribution), and It is determined that the second gradation distribution α4 [(α4g, α4b), (α4r, α4g)] exists in the frequency distribution (at least one of the red frequency distribution, the green frequency distribution, and the blue frequency distribution). In this case, the image data (red image data, green image data, and blue image data) is subjected to a predetermined second correction process (sharpening process) with a correction degree smaller than the correction degree corrected by the first correction process. )I do. Here, the second correction process is a process for sharpening the image portion corresponding to the second gradation distribution α4 [(α4g, α4b), (α4r, α4g)], and is a process for clarifying the gradation. Can be exemplified by the process of emphasizing. The details of the second correction process will be described in detail. The second correction process may be performed on the entire image data, or the image area to be corrected (non-fluorescent portion NL) may be separated and the image area to be corrected (non-fluorescent) should be corrected. The correction process may be performed on the partial NL).

In this way, in the frequency distribution (at least one of the red frequency distribution, the green frequency distribution, and the blue frequency distribution), the gradation distribution α1 (α1r, α1g, α1b) of the base BG and the gradation of the character CR. By determining the second gradation distribution α4 [(α4g, α4b), (α4r, α4g)] in which the gradation distribution is concentrated with the distribution α3 (α3r, α3g, α3b), the image sensor unit 240 ( In the image data (red image data, green image data, and blue image data) read in 216, 229), the non-fluorescent portion NL written by the color non-fluorescent writing tool can be recognized. Then, there is a second gradation distribution α4 [(α4g, α4b), (α4r, α4g)] in the frequency distribution (at least one of the red frequency distribution, the green frequency distribution, and the blue frequency distribution). When it is determined that the image data (red image data, green image data, and blue image data) is corrected in the second correction process, the second correction is performed with a correction degree smaller than the correction degree corrected by the first correction process. By performing the treatment, it is possible to reduce the thinning of the non-fluorescent portion NL written by the color non-fluorescent writing tool, thereby making the non-fluorescent portion NL stand out. This is particularly effective when the image sensor unit 240 is the close contact type image sensor unit 229 used in the close contact optical system of the image reading device 200.

(Second Embodiment)
FIG. 14 is a plan view showing the image IM of the manuscript G of the photograph, and a histogram showing the frequency distribution generated based on the image data as a graph.

As shown in FIG. 14, according to the findings of the present inventor, the gradation is generated based on the image data (red image data, green image data, and blue image data) read by the image sensor unit 240. In the frequency distribution (red frequency distribution, green frequency distribution, and blue frequency distribution), the degree of dispersion exceeds a predetermined degree on the darker side than the gradation distribution α1 (α1r, α1g, α1b) of the background BG of the original G (α1r, α1g, α1b). If there is a distributed gradation distribution α5 (below a predetermined degree of concentration), this dispersed gradation distribution α5 can be regarded as a photograph. In this case, if the first correction process and / or the second correction process is performed, the image quality of the photographic image may deteriorate. Therefore, if it is determined that a photograph exists in the frequency distribution (red frequency distribution, green frequency distribution, and blue frequency distribution), the image data (red image data, green image data, and blue image data) will be included. On the other hand, it is preferable to prohibit the first correction process and / or the second correction process.

In this regard, the control unit 251 includes a photo finish means P8 and a photo correction processing means P9, as shown in FIG. The control unit 251 functions as a means including a photo finish step corresponding to the photo finish means P8 and a photo finish processing step corresponding to the photo finish processing means P9.

In the photographic determination means P8, the gradation distribution is dispersed on the darker side than the gradation distribution α1 (α1r, α1g, α1b) of the base BG in the frequency distribution (red frequency distribution, green frequency distribution, and blue frequency distribution). The gradation distribution α5 (α5r, α5g, α5b) of the photograph is determined (determined respectively). Specifically, the photographic determination means P8 uses "dispersion" and / or "standard deviation" in the gradation region φ on the darker side than the gradation distribution α1 (α1r, α1g, α1b) of the background BG. When the degree of dispersion of the distribution is larger than the predetermined degree of dispersion (when the degree of concentration is smaller than the predetermined degree of concentration), it is determined that the gradation distribution is α5 (α5r, α5g, α5b) of the photograph.

The photo correction processing means P9 determines that the gradation distribution α5 (α5r, α5g, α5b) of the photograph exists in the frequency distribution (at least one of the red frequency distribution, the green frequency distribution, and the blue frequency distribution). In this case, the image data of the original G (red image data, green image data, and blue image data) is subjected to predetermined photo processing without performing the first correction processing and the second correction processing.

Here, as the predetermined photo processing, conventionally known processing can be used, for example, brightness conversion processing, contrast conversion processing, color balance processing, grayscale conversion processing, color space conversion processing, smoothing processing, and the like. Can be mentioned.

In this way, in the frequency distribution (at least one of the red frequency distribution, the green frequency distribution, and the blue frequency distribution), the floor is darker than the gradation distribution α1 (α1r, α1g, α1b) of the base BG. By determining the gradation distribution α5 (α5r, α5g, α5b) of a photograph in which the frequency distribution is dispersed, in the image data (red image data, green image data, and blue image data) read by the image sensor unit 240. Can recognize photos. Then, when it is determined that the gradation distribution α5 (α5r, α5g, α5b) of the photograph exists in the frequency distribution (at least one frequency distribution of the red frequency distribution, the green frequency distribution, and the blue frequency distribution), the photograph is taken. In the correction process, the image quality of the photographic image is obtained by performing a predetermined photo process on the image data (red image data, green image data, and blue image data) without performing the first correction process and the second correction process. Can be avoided from decreasing.

(Third Embodiment)
In the present embodiment, the first correction process is output by increasing the gradation difference between the maximum gradation and the minimum gradation of the red image data, the green image data, and the blue image data. This is a sharpening process for making an image clearer.

For example, in the first correction process, assuming that the input gradation is Ri, Gi, Bi and the output gradation is Ro, Go, Bo in the red image data, the green image data, and the blue image data, the following equation (1) ) Can be the process of calculation.

Specifically, assuming that the input gradations Ri, Gi, and Bi are 240, 240, and 200, the output gradations Ro, Go, and Bo are 248, 248, and 184. That is, with respect to the gradation difference (40) between the maximum value (240) and the minimum value (200) of the input gradations Ri, Gi, and Bi, the maximum value of the output gradations Ro, Go, and Bo (that is, The gradation difference (64) between the 248) and the minimum value (184) can be increased.

By doing so, the color of the fluorescent portion HL written by the color fluorescent writing instrument can be made vivid and conspicuous.

In the present embodiment, the degree of thinning of the non-fluorescent portion NL written by the color non-fluorescent writing tool is smaller than the degree of thinning of the fluorescent portion HL written by the color non-fluorescent writing tool. The gradation difference between the maximum gradation and the minimum gradation of the red image data, the green image data, and the blue image data is increased by a correction degree smaller than the correction degree corrected by the first correction process. This is a sharpening process for making the output image clearer.

For example, in the second correction process, assuming that the input gradation is Ri, Gi, Bi and the output gradation is Ro, Go, Bo in the red image data, the green image data, and the blue image data, the following equation (2) ) Can be the process of calculation.

Specifically, assuming that the input gradations Ri, Gi, and Bi are 240, 240, and 200, the output gradations Ro, Go, and Bo are 244, 244, and 192. That is, with respect to the gradation difference (40) between the maximum value (240) and the minimum value (200) of the input gradations Ri, Gi, and Bi, the maximum value of the output gradations Ro, Go, and Bo (that is, The gradation difference (52) between the 244) and the minimum value (192) can be increased.

By doing so, the color of the non-fluorescent portion NL written by the color non-fluorescent writing instrument can be made vivid and conspicuous.

In the first correction process and the second correction process, the colors of the fluorescent portion HL and the non-fluorescent portion NL are displayed in a matrix of red (R) image data, green (G) image data, and blue (B) image data. Although the color correction process for making the color vivid is illustrated, R, G, and B are converted into Y (brightness), Cb (blue color difference), and Cr (red color difference), and the color components Cb and Cr are converted. It may be processed in a matrix, or it may be performed in a three-dimensional color correction lookup table. The same applies to the correction processing for the first image sensor unit to the correction processing for the fourth image sensor unit, which will be described later.

In the present embodiment, the image sensor unit 240 (color image sensor unit) is in close contact with the reduced image sensor unit 216 (reduced color image sensor unit) used in the reduced optical system of the image reading device 200 and the image reading device 200. It includes a close contact type image sensor unit 229 (contact type color image sensor unit) used in an optical system.

By the way, when the image data (red image data, green image data, and blue image data) read by the close contact type image sensor unit 229 is output to the output device (displayed on the display device 231 or displayed on the image forming device main body 110). In the output image of the original G (when printed), the fluorescent portion HL written by the color fluorescent writing tool and / or the non-fluorescent portion NL written by the color non-fluorescent writing tool are read by the reduced image sensor unit 216. It is easy to be thin (easy to fade or dull) compared to the image data.

In this respect, the first correction process includes a predetermined correction process for the first image sensor unit and a predetermined correction process for the second image sensor unit. And / or, the second correction process includes a predetermined correction process for the third image sensor unit and a predetermined correction process for the fourth image sensor unit.

<Correction processing for the first image sensor unit>
The correction process for the first image sensor unit is the first gradation distribution α2 with respect to the image data (red image data, green image data, and blue image data) of the document G read by the close contact type image sensor unit 229. The image portion corresponding to (α2g, α2r, α2r) is sharpened.

For example, in the correction processing for the first image sensor unit, assuming that the input gradation is Ri, Gi, Bi and the output gradation is Ro, Go, Bo in the red image data, the green image data, and the blue image data, the following The process can be calculated by the equation (1) of.

Specifically, assuming that the input gradations Ri, Gi, and Bi are 240, 240, and 200, the output gradations Ro, Go, and Bo are 248, 248, and 184. That is, the gradation difference (64) between the maximum value and the minimum value of the output gradations Ro, Go, and Bo is the gradation difference (40) between the maximum value and the minimum value of the input gradations Ri, Gi, and Bi. ) Can be increased.

<Correction processing for the second image sensor>
The correction process for the second image sensor unit is a correction process for the first image sensor unit with respect to the image data (red image data, green image data, and blue image data) of the document G read by the reduced image sensor unit 216. The image portion corresponding to the first gradation distribution α2 (α2g, α2r, α2r) is made clear with a correction degree smaller than the correction degree corrected by the processing.

For example, in the correction processing for the second image sensor unit, assuming that the input gradation is Ri, Gi, Bi and the output gradation is Ro, Go, Bo in the red image data, the green image data, and the blue image data, the following The process can be calculated by the equation (2) of.

Specifically, assuming that the input gradations Ri, Gi, and Bi are 240, 240, and 200, the output gradations Ro, Go, and Bo are 244, 244, and 192. That is, the gradation difference (52) between the maximum value and the minimum value of the output gradations Ro, Go, and Bo is the gradation difference (40) between the maximum value and the minimum value of the input gradations Ri, Gi, and Bi. ) Can be increased.

<Correction processing for the third image sensor>
The correction process for the third image sensor unit is the second gradation distribution α4 with respect to the image data (red image data, green image data, and blue image data) of the document G read by the close contact type image sensor unit 229. The image portion corresponding to [(α4g, α4b), (α4r, α4g)] is sharpened.

For example, in the correction processing for the third image sensor unit, assuming that the input gradation is Ri, Gi, Bi and the output gradation is Ro, Go, Bo in the red image data, the green image data, and the blue image data, the following The process can be calculated by the equation (2) of.

Specifically, assuming that the input gradations Ri, Gi, and Bi are 240, 240, and 200, the output gradations Ro, Go, and Bo are 244, 244, and 192. That is, the gradation difference (52) between the maximum value and the minimum value of the output gradations Ro, Go, and Bo is the gradation difference (40) between the maximum value and the minimum value of the input gradations Ri, Gi, and Bi. ) Can be increased.

<Correction processing for the 4th image sensor section>
The correction process for the fourth image sensor unit is the correction process for the third image sensor unit for the image data (red image data, green image data, and blue image data) of the original read by the reduced image sensor unit 216. The image portion corresponding to the second gradation distribution α4 [(α4g, α4b), (α4r, α4g)] is sharpened with a correction degree smaller than the correction degree corrected by.

For example, in the correction processing for the fourth image sensor unit, assuming that the input gradation is Ri, Gi, Bi and the output gradation is Ro, Go, Bo in the red image data, the green image data, and the blue image data, the following The process can be calculated by the equation (3) of.

Specifically, assuming that the input gradations Ri, Gi, and Bi are 240, 240, and 200, the output gradations Ro, Go, and Bo are 242,242,196. That is, the gradation difference (46) between the maximum value (242) and the minimum value (196) of the output gradations Ro, Go, and Bo is set as the maximum value (240) of the input gradations Ri, Gi, and Bi. It can be increased with respect to the gradation difference (40) from the minimum value (200).

In the correction processing for the first image sensor unit to the correction processing for the fourth image sensor unit, the image data (red image data, green image data, and blue image data) of the document G read by the close contact type image sensor unit 229 is Even if the data is output to the output device, the image portion (fluorescent portion HL written by the color fluorescent writing tool) corresponding to the first gradation distribution α2 (α2g, α2r, α2r) and / Alternatively, the image portion (non-fluorescent portion NL written with a color non-fluorescent writing tool) corresponding to the second gradation distribution α4 [(α4g, α4b), (α4r, α4g)] can be conspicuous.

(Fourth Embodiment)
In the present embodiment, in the frequency distribution (at least one frequency distribution of the red frequency distribution, the green frequency distribution, and the blue frequency distribution), both the first gradation distribution α2 and the second gradation distribution α4 are present. If it is determined that it exists, the first correction process is performed in preference to the second correction process. By doing so, the second correction process can be omitted, and the processing time of the correction process can be shortened.

<Image processing control example>
Next, an example of image processing according to the present embodiment will be described below with reference to FIGS. 15 and 16.

15 and 16 are flowcharts showing an example of image processing according to the present embodiment.

In the image processing example according to the present embodiment, as shown in FIG. 15, first, the control unit 251 reads the image of the document G by the reduced image sensor unit 216 or the close contact type image sensor unit 229 (S1). Next, the control unit 251 quantizes the red image data, the green image data, and the blue image data read by the reduced image sensor unit 216 or the close contact type image sensor unit 229 into gradations of 0 to 255 (S2). ), A red frequency distribution, a green frequency distribution, and a blue frequency distribution with respect to the gradation of the quantized image data are generated (S3). At this time, the generated red, green, and blue frequency distributions are stored in the storage unit 251b.

Next, the control unit 251 determines the gradation distribution α1 of the background BG of the document G in which the gradation distribution is most concentrated in each of the red, green, and blue frequency distributions (S4), and determines the gradation distribution α1 of the background BG. The first gradation distribution α2 in which the gradation distribution is concentrated on the brighter side is determined (S5). Further, the control unit 251 determines the gradation distribution α3 of the character CR of the manuscript G in which the gradation distribution is most concentrated on the darker side than the gradation distribution α1 of the base BG in each of the red, green, and blue frequency distributions ( S6), a second gradation distribution in which the gradation distribution is concentrated between the gradation distribution α1 of the base BG and the gradation distribution α3 of the character CR in at least one frequency distribution among the red, green and blue frequency distributions. Determine α4 (S7).

Next, the control unit 251 determines the gradation distribution α5 of the photograph in which the gradation distribution is dispersed on the darker side than the gradation distribution α1 of the base BG in each frequency distribution of red, green, and blue (S8). The process proceeds to the process shown in 16.

As shown in FIG. 16, the control unit 251 determines whether or not the gradation distribution α5 of the photograph exists in at least one frequency distribution among the red, green, and blue frequency distributions (S9), and determines whether or not the gradation distribution α5 of the photograph exists (S9), and the floor of the photograph. When it is determined that the frequency distribution α5 exists (S9: Yes), a predetermined photographic process is performed (S10), and the process is terminated.

On the other hand, when the control unit 251 determines that the gradation distribution α5 of the photograph does not exist (S9: No), whether or not the first gradation distribution α2 exists in each frequency distribution of red, green, and blue. (S11), and if it is determined that the first gradation distribution α2 exists (S11: Yes), it is determined whether or not it is the image data of the original G read by the close contact type image sensor unit 229. (S12).

Next, when the control unit 251 determines that it is the image data of the document G read by the close contact type image sensor unit 229 (S12: Yes), the first image reading unit is used to clarify the fluorescent portion HL. Performs correction processing (S13) and ends the processing. On the other hand, when the control unit 251 determines that it is the image data of the document G read by the reduced image sensor unit 216 (S12: No), the control unit 251 is for the first image reading unit in order to clarify the fluorescent portion HL. The correction process for the second image reading unit, which has a smaller degree of correction than the correction process, is performed (S14), and the process ends.

Further, when the control unit 251 determines that the first gradation distribution α2 does not exist (S11: No), whether the second gradation distribution α4 exists in each of the red, green, and blue frequency distributions. Whether or not it is determined (S15), and if it is determined that the second gradation distribution α4 does not exist (S15: No), the process ends. On the other hand, when the control unit 251 determines that the second gradation distribution α4 exists (S15: Yes), the control unit 251 determines whether or not it is the image data of the document G read by the close contact type image sensor unit 229. (S16).

Next, when the control unit 251 determines that it is the image data of the document G read by the close contact type image sensor unit 229 (S16: Yes), the control unit 251 reads a third image in order to clarify the non-fluorescent portion NL. A partial correction process is performed (S17), and the process ends. On the other hand, when the control unit 251 determines that it is the image data of the document G read by the reduced image sensor unit 216 (S16: No), the control unit 251 is a third image reading unit in order to clarify the non-fluorescent portion NL. The correction process for the fourth image reading unit, which has a smaller degree of correction than the correction process for, is performed (S18), and the process is completed.

The present invention is not limited to the embodiments described above, and can be implemented in various other forms. Therefore, such embodiments are merely exemplary in all respects and should not be construed in a limited way. The scope of the present invention is shown by the claims and is not bound by the text of the specification. Furthermore, all modifications and modifications that fall within the equivalent scope of the claims are within the scope of the present invention.

100 Image forming device 110 Image forming device main body 200 Image reading device 216 Reduction type image sensor unit 229 Close contact type image sensor unit 230 Operation unit 231 Display device 240 Image sensor unit 250 Image processing device 251 Control unit 251a Processing unit 251b Storage unit BG base CR character G Manuscript HL Fluorescent part IM Image MK mark NL Non-fluorescent part P1 Frequency distribution generation means P2 Base judgment means P3 First judgment means P4 First correction processing means P5 Character judgment means P6 Second judgment means P7 Second correction processing means P8 Photo determination means P9 Photo correction processing means α1 Underground gradation distribution α2 First gradation distribution α3 Character gradation distribution α4 Second gradation distribution α5 Photo gradation distribution

Claims (13)

An image processing device that processes the image data of the original read by the image sensor unit.
A frequency distribution generating means that generates a frequency distribution with respect to gradation based on the image data read by the image sensor unit, and
A background determination means for determining the gradation distribution of the background of the document in which the gradation distribution is most concentrated in the frequency distribution, and
A first determination means for determining a first gradation distribution in which the gradation distribution is concentrated on a side brighter than the gradation distribution of the background in the frequency distribution.
A first correction processing means that performs a predetermined first correction process on the image data when it is determined that the first gradation distribution exists in the frequency distribution.
An image processing device comprising. The image processing apparatus according to claim 1.
The image sensor unit includes a reduced image sensor unit used for the reduced optical system of the image reading device and a close contact type image sensor unit used for the close contact optical system of the image reading device.
The first correction process is
A predetermined correction process for the first image sensor unit performed on the image data of the document read by the reduced image sensor unit, and
A predetermined correction process for the second image sensor unit performed with a correction degree larger than the correction degree for the image data of the document read by the close contact type image sensor unit in the correction process for the first image sensor unit. ,
An image processing apparatus comprising. The image processing apparatus according to claim 1 or 2.
A character determination means for determining the gradation distribution of characters in the document in which the gradation distribution is most concentrated on the darker side than the gradation distribution of the background in the frequency distribution.
A second determination means for determining a second gradation distribution in which the gradation distribution is concentrated between the gradation distribution of the background and the gradation distribution of the characters in the frequency distribution.
When it is determined that the first gradation distribution does not exist in the frequency distribution and it is determined that the second gradation distribution exists, the image data is corrected by the first correction process. A second correction processing means that performs a predetermined second correction process with a correction degree smaller than the degree, and
An image processing device comprising. The image processing apparatus according to claim 3.
The image sensor unit includes a reduced image sensor unit used for the reduced optical system of the image reading device and a close contact type image sensor unit used for the close contact optical system of the image reading device.
The second correction process is
A predetermined correction process for the third image sensor unit performed on the image data of the original document read by the reduced image sensor unit, and
A predetermined correction process for the fourth image sensor unit performed with a correction degree larger than the correction degree for the image data of the document read by the close contact type image sensor unit in the correction process for the third image sensor unit. ,
An image processing apparatus comprising. The image processing apparatus according to claim 3 or 4.
When it is determined that both the first gradation distribution and the second gradation distribution exist in the frequency distribution, the first correction processing is performed in preference to the second correction processing. Image processing device. The image processing apparatus according to any one of claims 1 to 5.
A photo finish means for determining the gradation distribution of a photograph in which the gradation distribution is dispersed on a darker side than the gradation distribution of the background in the frequency distribution.
A photographic correction processing means that performs a predetermined photographic process on the image data without performing the first correction process when it is determined that the gradation distribution of the photographic exists in the frequency distribution.
An image processing device comprising. The image processing apparatus according to claim 1.
The image sensor unit is a color image sensor unit.
The frequency distribution generating means generates a red frequency distribution, a green frequency distribution, and a blue frequency distribution with respect to gradation based on the red image data, the green image data, and the blue image data read by the color image sensor unit. Generate each
The background determination means determines the gradation distribution of the background of the manuscript based on the red frequency distribution, the green frequency distribution, and the blue frequency distribution, respectively.
In the first determination means, the gradation distribution is concentrated on a side brighter than the gradation distribution of the background in at least one frequency distribution of the red frequency distribution, the green frequency distribution, and the blue frequency distribution. Judge the gradation distribution of 1 and
When the first correction processing means determines that the first gradation distribution exists in at least one of the red frequency distribution, the green frequency distribution, and the blue frequency distribution, the red color distribution. An image processing apparatus, characterized in that a predetermined first correction process is performed on the image data, the green image data, and the blue image data. The image processing apparatus according to claim 7.
The first correction process is characterized in that it is a process for increasing the gradation difference between the maximum gradation and the minimum gradation of the red image data, the green image data, and the blue image data. Image processing device. The image processing apparatus according to claim 7.
Character determination for determining the gradation distribution of characters in the manuscript in which the gradation distribution is most concentrated on the darker side than the gradation distribution of the background in the red frequency distribution, the green frequency distribution, and the blue frequency distribution. Means and
A second in which the gradation distribution is concentrated between the gradation distribution of the background and the gradation distribution of the characters in at least one frequency distribution of the red frequency distribution, the green frequency distribution, and the blue frequency distribution. A second determination means for determining the gradation distribution of
It is determined that the first gradation distribution does not exist in any of the red frequency distribution, the green frequency distribution, and the blue frequency distribution, and the red frequency distribution and the green frequency distribution. When it is determined that the second gradation distribution exists in at least one frequency distribution among the distribution and the blue frequency distribution, with respect to the red image data, the green image data, and the blue image data. A second correction processing means that performs a predetermined second correction process with a correction degree smaller than the correction degree corrected by the first correction process.
An image processing device comprising. The image processing apparatus according to claim 9.
The first correction process is a process for increasing the gradation difference between the maximum gradation and the minimum gradation of the red image data, the green image data, and the blue image data.
The second correction process is a correction in which the gradation difference between the maximum gradation and the minimum gradation of the red image data, the green image data, and the blue image data is corrected by the first correction process. An image processing device characterized in that it is a process of increasing a correction degree smaller than the degree. An image reading device comprising the image processing device according to any one of claims 1 to 10. An image forming apparatus comprising the image processing apparatus according to any one of claims 1 to 10 or the image reading apparatus according to claim 11. It is an image processing method that processes the image data of the original read by the image sensor unit.
A generation step of generating a frequency distribution with respect to gradation based on the image data read by the image sensor unit, and
A background determination step for determining the gradation distribution of the background of the document in which the gradation distribution is most concentrated in the frequency distribution, and
In the frequency distribution, the first determination step of determining the first gradation distribution in which the gradation distribution is concentrated on the side brighter than the gradation distribution of the background, and
When it is determined that the first gradation distribution exists in the frequency distribution, the first correction processing step of performing a predetermined first correction processing on the image data and the first correction processing step.
An image processing method comprising.

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