Image processing apparatus, image processing method, and program

Abstract

To appropriately reduce a color component derived from a fluorescent coloring material from a read image obtained by scanning a document marked with the fluorescent coloring material.SOLUTION: A main control section scans a document with a reading unit, acquires a scanned RGB image, estimates the color of a fluorescent coloring material from the acquired scanned RGB image, and identifies the wavelength region of the fluorescence emission light generated from the fluorescent coloring material in the estimated color. The main control section scans the document in a similar manner, and acquires a fluorescence emission image having, as a pixel value, the amount of fluorescence emission in the identified wavelength region of the fluorescence emission light. An image processing section estimates the amount of fluorescence emission in each pixel value of the scanned RGB image from the acquired fluorescence emission image. The image processing section performs correction so as to reduce the color component derived from the fluorescent coloring material of the scanned RGB image on the basis of the detected or calculated amount of fluorescence emission and amount of fluorescence absorption for every channel, and thereby creates a corrected scanned RGB image with color development closer to that of an original document.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an image processing technique for processing an image obtained by scanning with a scanner. [Background technology]

[0002] Traditionally, marking printed matter with highlighters or red pens has been a common method for highlighting specific areas in a document. However, marking alters the original document, and there are cases where the original document needs to be restored to its pre-marking state. In such cases, there is a method for scanning the original document and removing the color used for marking from the scanned image.

[0003] Patent document 1 discloses a method in which, when reading a document, a user specifies the color they want to remove, and the hue range of the color to be removed is set based on the specified color, and the surrounding area of ​​the specified color is removed from the read image of the document based on the set hue range. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-72402 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the technology of Patent Document 1, when a scanner is used that has a sensor with flat light receiving sensitivity over the entire wavelength range and recognizes the wavelength of light irradiated on a document as the wavelength of light detected by the sensor, the color components derived from the highlighter cannot be appropriately reduced. The fluorescent coloring material used in the highlighter absorbs light of a specific wavelength from the irradiated light and emits light of a wavelength different from the absorbed light, which is a light emission phenomenon. Therefore, when a document marked with a highlighter is read by a scanner of the above configuration, the scanner mistakenly recognizes the color of the light emitted from the fluorescent coloring material as the color of the light absorbed by the fluorescent coloring material. As a result, even if the hue range of the color to be removed is set based on the specified color as in Patent Document 1, the misidentified color components derived from the highlighter are not reduced.

[0006] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to appropriately reduce color components derived from fluorescent color materials from a read image obtained by scanning an original marked with a fluorescent color material. [Means for solving the problem]

[0007] The present invention is an image processing device comprising: a first acquisition means for acquiring a read image obtained by reading an original document marked with a fluorescent color material, with each pixel consisting of pixel values ​​having a plurality of color components; a second acquisition means for acquiring a fluorescent emission image representing the amount of fluorescent emission obtained by reading light emitted from the marked portion of the original document; and a correction means for correcting the read image based on the fluorescent emission image so as to reduce color components originating from the fluorescent color material. Effect of the Invention

[0008] According to the present invention, it is possible to appropriately reduce color components derived from fluorescent color materials from a read image obtained by scanning an original marked with a fluorescent color material. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is an explanatory diagram of the control configuration of a multifunction printer (MFP) device, which is an example of an image processing device. [Diagram 2] An explanatory diagram of an MFP device and an inkjet recording device. [Diagram 3] Illustration of a reading device [Figure 4] Diagram explaining the excitation and emission of fluorescent pink material [Diagram 5] Diagram explaining read signal values [Figure 6] 1 is a flowchart showing image processing according to the present invention; [Figure 7] A functional block diagram for performing image processing in the first embodiment. [Figure 8] FIG. 1 is a diagram for explaining a method for estimating the amount of fluorescence absorption in the present invention. [Figure 9] FIG. 11 is a diagram for explaining a state of color material application on a paper surface in the second embodiment; [Figure 10] FIG. 11 is a block diagram of a function for performing image processing according to the second embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The following describes an embodiment.

[0011] (First embodiment) 1 is a hardware block diagram for explaining the control configuration of a multifunction printer (MFP) device, which is an example of an image processing device according to this embodiment. The multifunction printer (MFP) device in this embodiment includes an inkjet recording device (hereinafter also simply referred to as a recording device) and a reading device that optically reads an original.

[0012] In FIG. 1, the main control unit 101 controls the entire printing system, and is composed of a CPU, a ROM, a RAM, etc. The image processing unit 102 creates images and controls image data, and performs various image processing, which will be described later. The image processing unit 102 is composed of a CPU, a ROM, a RAM, etc. The recording buffer 105 can store image data before being transferred to the recording head 104 as raster data. The recording head 104 is an inkjet type recording head having a plurality of recording elements capable of ejecting ink droplets, and ejects ink from each recording element according to the image data stored in the recording buffer 105. The reading buffer 107 can store image data read by the reading unit 106. The reading unit 106 is composed of a light source, a lens, and a sensor, and scans an original to generate read image data. The mechanism control unit 108 performs various mechanism controls, such as conveying and feeding / ejecting the recording medium, moving the carriage carrying the recording head 104, and moving the reading unit 106. The display unit 110 displays various information to the user, and can be, for example, an LCD. The operation unit 109 is an operation unit for a user to perform operations, and can be, for example, a button or a touch panel. The system bus 111 connects the components of the recording system. The interface (I / F) 103 is a connection unit for connecting to an external device such as a PC, and printing, scanning, and copying via a PC are also possible.

[0013] 2(a) is a schematic perspective view of an MFP device according to an embodiment of the present invention. This MFP device 201 has a function as a normal PC printer that receives and prints data from a host computer (PC), and a function as a scanner. Furthermore, as a function that operates independently of the MFP device 201, it has a copy function that prints an image read by a scanner with a printer.

[0014] 2(a), an MFP device 201 is composed of a reading device 202 such as a flatbed scanner, an inkjet recording device 203, and an operation panel 205 equipped with a display panel 204 and various key switches, etc. Also, a USB port (not shown) for communicating with a PC is provided on the back of the MFP device 201, and communication with the PC is performed.

[0015] FIG. 2B is a diagram for explaining the inkjet recording device 203 in FIG. 2A. The carriage 213 has a recording head 211, ink tanks 212K, 212C, 212M, and 212Y, and an optical sensor 214. The ink tanks 212K, 212C, 212M, and 212Y contain black (K), cyan (C), magenta (M), and yellow (Y) inks, respectively, and the inks are appropriately provided to the recording head. The carriage 213 can reciprocate along the X direction in the figure (so-called main scanning direction) by the driving force of a carriage motor transmitted via a belt 215. While the carriage 213 is moving in the X direction relative to the recording medium, ink is ejected from each nozzle of the nozzle row toward the paper surface (in the -z direction in the figure) based on recording data. As a result, an image for one main scanning pass is recorded on the recording medium placed on the platen 216. When one main scan is completed, the recording medium is transported in the transport direction (in the -y direction in the figure) a distance corresponding to the width of one main scan. By alternately repeating such main scans and transport operations, an image is gradually formed on the recording medium. The optical sensor 214 performs a detection operation while moving together with the carriage 213, and can determine whether or not a recording medium is present on the platen 216, and by detecting a special pattern, can determine nozzle non-ejection, ejection position deviation, etc.

[0016] FIG. 3(a) is a diagram for explaining the reading device 202 in FIG. 2(a). The reading device 202 is composed of a platen glass 302 and a scanner unit 303. A document 308 is placed on the platen glass 302. The scanner unit 303 includes a light source 304, a lens 305 for collecting light, and a sensor 306. In this embodiment, the light source 304 is three LEDs that emit red, green, and blue colors, and is arranged so that the incident light is incident on the document at a certain angle. The light reflected by the document 308 is collected by the lens 305 and detected by the sensor 306. The sensor 306 generates color component values ​​that constitute pixel values ​​of the read image based on the intensity of the detected light and the color of the light source that was irradiated at the time of detection. That is, the three LEDs of the light source are turned on individually in sequence, and signals for three channels of RGB that constitute each pixel value of the read image are generated based on signal values ​​indicating the intensity of the light detected by the sensor at the respective lighting timings. The sensor 306 is positioned so as to receive reflected light at an angle different from the angle at which the incident light is incident. In other words, this reading device reads diffuse light rather than specularly reflected light from the original. The scanner unit 303 can move in the Y direction in the figure, and can scan a white reference plate 307 placed under the original platen glass 302 and the original area. The scanner unit 303 reads the white reference plate 307 as appropriate, and corrects for variations in the light source 304 and the sensor 306.

[0017] 3(b) and (c) are diagrams for explaining the sensor 306. In this embodiment, in addition to a so-called W (white) sensor that receives light in the entire wavelength range for normal image acquisition, a red filter for detecting fluorescence is provided, and an R sensor that receives light only in the red wavelength range (590 nm to 780 nm) is provided. Since light emitted by a fluorescent color material emits light with a longer wavelength than the incident light, an R sensor that can detect only the red wavelength range is effective.

[0018] The sensor unit 310 shown in Fig. 3(b) has a total of two sensor rows: a W sensor row 311 that receives light in the entire wavelength range, and an R sensor row 312 equipped with a red filter. Each sensor row has a plurality of sensors arranged in the X direction, and the pitch between the sensors in each sensor row is such that a read image of 600 dpi can be obtained. Therefore, the read images obtained by both the W sensor row 311 and the R sensor row 312 have a resolution of 600 dpi.

[0019] 3(c), W sensors are arranged at intervals that allow a 600 dpi read image to be obtained, and R sensors are arranged in the same sensor row at intervals that allow a 150 dpi read image to be obtained. Therefore, a read image obtained using this sensor row 313 is made up of an image area with a resolution of 600 dpi obtained by the W sensor 314 and an image area of ​​150 dpi obtained by the R sensor 315. Note that although the image area obtained by the W sensor 314 has gaps at 150 dpi intervals across the entire read image, the gaps can be complemented by a conventionally known method.

[0020] A fluorescent color material is a color material that absorbs light of an excitation wavelength from a ground state to become an excited state, and returns to the ground state when it emits light of an emission wavelength. FIG. 4(a) is a graph showing the intensity of excitation light 401 and emission light 402 absorbed by a fluorescent pink color material for each wavelength, with the horizontal axis representing the wavelength of light and the vertical axis representing the intensity. This graph shows the intensity of light when the wavelength of light irradiated to a sample and the wavelength of light received from the sample are changed, respectively. The emission light 402 shows the intensity of light received from a sample for each wavelength when the sample is irradiated with light of an exciting wavelength. The emission light 402 in FIG. 4(a) is a graph showing the intensity of light of wavelengths other than 480 nm among the light emitted from the sample when the fluorescent pink sample is irradiated with light of 480 nm. The excitation light 401 in FIG. 4(a) is a graph showing the intensity of the irradiated light absorbed by the sample, which is observed as an emission light of 600 nm when the sample is irradiated with light. As can be seen from FIG. 4, the wavelength region of the fluorescent pink excitation light 401 recorded on the paper surface is a region on the short wavelength side, partially overlapping with the wavelength region of the emitted light. In addition, the intensity of the absorption of the excitation light 401 varies depending on the wavelength, and there are wavelengths that efficiently cause emission and wavelengths that do not. Furthermore, the graph shown in FIG. 4(a) shows that the fluorescent color material used in the sample is excited by light with a wavelength of about 450 nm to 600 nm, which is the wavelength region of visible light. Since the fluorescent color material emits light, the reflectance at the emission wavelength often exceeds 1. In the present embodiment, a color material having the above characteristics is hereinafter referred to as a "fluorescent color material".

[0021] The above describes the excitation and emission of fluorescent pink, but there are fluorescent colorants that emit light of other wavelengths, such as the following. For example, there is fluorescent blue that emits light in the blue region (450 nm to 500 nm), and fluorescent green that emits light in the green region (500 nm to 565 nm). In addition, fluorescent yellow that emits light in the yellow region (565 nm to 590 nm), and fluorescent orange or fluorescent red that emits light in the red region (590 nm to 780 nm) have also been put to practical use. Furthermore, there are also combinations of the above fluorescent colorants that have been used to adjust the color tone. Examples of fluorescent colorants include NKW-3207E (fluorescent pink aqueous dispersion: Nippon Kinko Kagaku Co., Ltd.) and NKW-3205E (fluorescent yellow aqueous dispersion: Nippon Kinko Kagaku Co., Ltd.).

[0022] In the present embodiment, a color material that does not absorb light of a specific wavelength among irradiated light and emit light is referred to as a “non-fluorescent color material.” Unlike fluorescent color materials, non-fluorescent color materials only absorb and reflect light and do not emit light, so their reflectance does not exceed 1.

[0023] Furthermore, when a fluorescent color material is mixed with a non-fluorescent color material to form a secondary color, an effect occurs due to the luminescence phenomenon unique to the fluorescent color material. Figure 4(b) is a graph of light wavelength on the horizontal axis and intensity on the vertical axis, and like Figure 4(a), it shows the intensity of excitation light 401 and emission light 402 of a sample coated with fluorescent pink, and further shows the reflection and absorption spectra of non-fluorescent color materials cyan 403, magenta 404, and yellow 405.

[0024] When fluorescent pink and cyan 403 are mixed, the cyan color material has a property of absorbing light in a wavelength region longer than 550 nm, and this wavelength region overlaps with the wavelength region of the fluorescent pink emission light 402. Therefore, the cyan color material absorbs light in the wavelength region of the fluorescent pink emission light 402. In other words, the cyan color material absorbs the light emitted by the fluorescent pink color material, and the emitted light is suppressed. When fluorescent pink and magenta 404 are mixed, the magenta color material has a property of absorbing light in a wavelength region near 500 to 550 nm, and this wavelength region overlaps with the wavelength region of the excitation light 401 that has high excitation sensitivity for fluorescent pink. Therefore, the incident light is largely absorbed by the magenta color material, and the amount of light that contributes to the excitation of fluorescent pink is reduced. As a result, fluorescent pink is not sufficiently excited, and emission is suppressed. When fluorescent pink and yellow 405 are mixed, similar to the example of mixing with magenta, yellow absorbs light in the wavelength region of the fluorescent pink excitation light 401. Therefore, the fluorescent pink is not sufficiently excited because the excitation light 401 is absorbed by the yellow, and the emission of light is suppressed. When fluorescent pink is mixed with a black material (not shown), the black material absorbs light of all wavelengths, and both the excitation light 401 and the emission light 402 are absorbed by the black material. Therefore, the excitation of the fluorescent pink is suppressed, and in addition, the emission light is also absorbed, so the amount of fluorescent light emitted by the fluorescent pink is greatly reduced.

[0025] As described above, when a fluorescent pink color material is mixed with a non-fluorescent color material, the amount of fluorescent light emitted by the fluorescent pink color material decreases, and the color of the fluorescent pink color material changes.

[0026] The printed matter on which the marking is applied by the highlighter pen may be printed by the inkjet method, the electrophotographic method, or the offset method. These printed matters are usually formed in four colors, cyan, magenta, yellow, and black. Therefore, the absorption spectrum of the marked fluorescent coloring material as described above affects the color of the fluorescence.

[0027] In the following, in this specification, the light component of the wavelength of the incident light that is selectively absorbed is called "absorption", and the color that is exhibited by "absorption" is called "absorption color". The light that is not absorbed is reflected. Furthermore, the light component that is excited by the irradiated light and shifted to another wavelength and output is called "emission", and the color that is exhibited by "emission" is called "emission color". In a normal non-fluorescent coloring material, there is an absorption component for each wavelength. In a fluorescent coloring material, in addition to the absorption component for each wavelength, there is an emission component at a specific wavelength. Note that in a fluorescent coloring material, the amount of the fluorescent emission component and the amount of the fluorescent absorption component are correlated. Figure 4(c) is a schematic diagram explaining absorption and emission. Figure 4(c) is a graph with the wavelength of light on the horizontal axis and the intensity on the vertical axis. Spectrum 406 shows the "absorption" component that has only a small intensity relative to the intensity "1" in a specific wavelength region. Spectrum 407 shows the "emission" component that has a large intensity relative to the intensity "1" in a specific wavelength region.

[0028] Figure 4(d) is an example of the spectral reflectance of fluorescent pink measured with a spectrophotometer. As with the other graphs, the horizontal axis is the wavelength of light, and the vertical axis is the intensity. The area 408 near red where the intensity exceeds 1 is the "emission" component caused by the fluorescent color material, and the drop-off area 409 near green is the "light absorption" component.

[0029] The coloring characteristics in the read image obtained by the scanner are different between fluorescent and non-fluorescent materials. The following describes the read signals of fluorescent and non-fluorescent materials. FIG. 5(a) shows the emission wavelength of the light source LED and the sensitivity of the sensor receiving the light of the scanner applied in this embodiment. The horizontal axis is the wavelength of light, and the vertical axis is the graph of the emission intensity for the LED and the light receiving sensitivity for the sensor. Here, three colors of LEDs are used as the light source. As shown in FIG. 5(a), there are three LEDs: R-LED 501 that has a peak wavelength in the red region and emits red light, G-LED 502 that has a peak wavelength in the green region and emits green light, and B-LED 503 that has a peak wavelength in the blue region and emits blue light. The light receiving sensitivity of the sensor 504 is almost uniform over the entire wavelength region.

[0030] Generally, light sources equipped with RGB-LEDs use a sequential lighting method in which the RGB LEDs are lit in sequence, and the amount of light received when each LED is lit is used as the signal value for each RGB channel. The signal value obtained by digitally converting the amount of light received when the R-LED is lit becomes the signal value for the R-channel (ch). Similarly, the signal value obtained by digitally converting the amount of light received when the G-LED is lit becomes the signal value for the G-channel (ch), and the signal value obtained by digitally converting the amount of light received when the B-LED is lit becomes the signal value for the B-channel (ch). Once the R, G, and B LEDs have finished lighting in sequence, the signal values ​​for the 3 RGB channels for each pixel can be obtained.

[0031] In the case of non-fluorescent color materials, the irradiated light is reflected or absorbed depending on the color material, so the wavelength of the light received by the sensor will not be outside the wavelength range of the irradiated light. Therefore, when an R-LED is irradiated, the reflected light with a wavelength within the wavelength range of the R-LED is received by the sensor and becomes the R-ch signal value. The same is true for G and B. In other words, the signal values ​​of each RGB channel are defined on the premise that the wavelength range of the received light is at least a part of the wavelength range of the irradiated light.

[0032] On the other hand, in the case of fluorescent color materials, light is emitted at a longer wavelength side than the wavelength of the irradiated light, and the light received by the sensor contains light with a wavelength outside the wavelength range of the irradiated light. Therefore, even when fluorescent color materials are included, if the signal values ​​of each channel of RGB are defined on the premise that the wavelength range of the received light is at least a part of the wavelength range of the irradiated light, an error will occur in the signal value. FIG. 5(b) shows the emission wavelengths of the light source LEDs 501 to 503 of the scanner applied in this embodiment and the wavelength of the excitation light 401 of the fluorescent pink color material. The fluorescent pink color material is the same as that shown in FIG. 4(a). As shown in FIG. 5(b), the B-LED 503 and G-LED 502 overlap with the wavelength range that causes excitation, but the R-LED 501 does not overlap at all. This means that when the B-LED 503 and G-LED 502 are irradiated, the fluorescent pink color material emits light at about 600 nm, and does not emit light when irradiated by the R-LED 501. It should be noted that 600 nm is a region that is generally considered to be "red."

[0033] FIG. 5(c) is a diagram showing the wavelength and amount of light emitted when the G-LED 502 is irradiated onto a document using a fluorescent pink coloring material. As before, the horizontal axis is the wavelength of light, and the vertical axis is the intensity. The sensor receives reflected light 510 at about 520 nm caused by the G-LED 502 and emitted light 511 at about 600 nm excited by the G-LED 502. The signal value of G-ch corresponds to the value obtained by integrating the intensity of light for each wavelength received. In this case, the intensity of the reflected light 510 in the green region and the emitted light 511 in the red region are added to the signal value of G-ch. Similarly, when the B-LED 503 is irradiated, the intensity of the emitted light in the red region is added to the signal value of B-ch.

[0034] In contrast, Fig. 5(d) is a diagram showing the wavelength characteristics of light emitted when the R-LED 501 is irradiated onto a document using a fluorescent pink material. Since the wavelength region of the R-LED 501 does not overlap with the wavelength region of the excitation light of the fluorescent pink material, no light is emitted even when the R-LED 501 is irradiated. Therefore, the amount of light received by the sensor when the R-LED 501 is irradiated is the reflected light 512 that is reflected without being absorbed in the wavelength region of the R-LED 501, and only the intensity of the reflected light 512 in the red region becomes the signal value of R-ch.

[0035] As mentioned above, in the read image obtained by the conventional scanning method, the luminous component cannot be correctly obtained as the signal value of the ch corresponding to its wavelength. Since the luminous component is red light, it should be added to R-ch as a signal value, but in reality it is not added to R-ch, but is added to B-ch and G-ch. This is the reason why when an original coated with fluorescent coloring material is scanned, the image becomes low in saturation. In addition, it is difficult to distinguish whether the saturation of the read image is low because a fluorescent coloring material is used and therefore the saturation of the original itself is low because a small amount of non-fluorescent coloring material is applied, and therefore the saturation of the read image is also low.

[0036] 6 is a flowchart showing image processing according to this embodiment, which shows the process that is executed when an original document having a portion marked with a highlighter or the like is placed on the reading unit 106 and a user issues an instruction to start copying or scanning on the operation unit 109 or the UI of a connected PC.

[0037] In S601, the main control unit 101 scans an original document using the reading unit 106, and obtains a scanned RGB image.

[0038] In S602, the main control unit 101 estimates the color of the fluorescent color material from the acquired scanned RGB image, and identifies the wavelength range of the fluorescent light generated by the fluorescent color material of the estimated color. The color of the fluorescent color material is estimated from the color of the fluorescent color material that can be recognized on the scanned RGB image. For example, if pink is detected, the color of the fluorescent color material is estimated to be fluorescent pink, and if yellow is detected, the color of the fluorescent color material is estimated to be fluorescent yellow. Then, based on previously stored information that associates the color of the fluorescent color material with the wavelength range of the fluorescent light, the wavelength range of the fluorescent light generated by the fluorescent color material of the estimated color is identified.

[0039] In S603, the main control unit 101 similarly scans the document using the reading unit 106, and obtains a fluorescence image having, as pixel values, the amount of fluorescence in the wavelength region of the fluorescence light identified in S602. If necessary, the scan is repeated, or a fluorescence image in each of the RGB channels is generated by performing calculations from the obtained amount of fluorescence.

[0040] In S604, the image processing unit 102 estimates the amount of fluorescence absorption at each pixel value of the scanned RGB image from the acquired fluorescent emission image.

[0041] In S605, the image processing unit 102 corrects the scanned RGB image to reduce color components derived from the fluorescent coloring materials based on the detected or calculated amount of fluorescent emission and amount of fluorescent absorption for each channel, and generates a corrected scanned RGB image close to the color of the original document. Here, the color of the original document refers to the color of the original document before it is marked with a highlighter pen.

[0042] In S606, the image processing unit 102 determines whether the user's instruction is "copy." If the user's instruction is "copy" (Yes), the process proceeds to S607, and if not (No), the process proceeds to S608. The output data generated here is print data that specifies the amount of color material for printing. If the user's instruction is "scan", the corrected scanned RGB image is used as output data as is.

[0043] In S607, the image processing unit 102 converts the corrected scanned RGB image into print data for driving the recording head 104 to perform printing, and generates output data.

[0044] In S608, the image processing unit 102 outputs the corrected scanned RGB image as is as output data. The corrected scanned RGB image can be displayed on a display device such as a monitor or saved in a storage device.

[0045] 7 is a functional block diagram for performing image processing according to this embodiment. A scanned RGB image acquisition unit 701 acquires a scanned RGB image of RGB 3ch from the reading unit 106. The scanned RGB image acquisition unit 701 drives the mechanism control unit 108 to operate the reading unit 106 under the control of the main control unit 101 in accordance with a copy or scan operation start command accepted by the operation unit. The scanned RGB image read by the reading unit 106 is stored in a reading buffer 107.

[0046] Similarly, the fluorescence emission amount acquisition section 702 acquires an image having the fluorescence emission amount as the pixel value from the reading unit 106. The acquired image of the fluorescence emission amount is stored in the reading buffer 107, similar to the scanned RGB image. The output of the fluorescence emission amount acquisition section 702 is an image having signal values ​​of three RGB channels as pixel values. This may be done by repeating multiple scans to acquire the three channels, or the fluorescence emission amount in each channel may be calculated from data acquired in a single scan.

[0047] A fluorescence absorption amount estimation unit 703 uses the image processing unit 102 to estimate the fluorescence absorption amount for each pixel based on the fluorescence emission image stored in the reading buffer 107 .

[0048] The image correction unit 704 corrects the scanned RGB image based on the acquired amount of fluorescent emission and the estimated amount of fluorescent absorption using the image processing unit 102 to generate a corrected RGB image. The corrected scanned RGB image is image data obtained by reducing color components derived from fluorescent color materials from the scanned RGB image.

[0049] The output unit 705 processes the corrected scanned RGB image according to an instruction from the user and outputs the image. If the instruction from the user is to "copy", the processing according to the instruction is a conversion process into print data that specifies the amount of color material for printing. The generated print data is stored in the recording buffer 105 and can be printed by sending it to the recording head 104. If the instruction from the user is to "scan", the corrected RGB image is sent to a display device such as a monitor and displayed to the user, or is saved in a storage device such as a hard disk.

[0050] Each process will now be described in detail. It is assumed that the original is partially marked with a fluorescent pink pen containing a fluorescent pink coloring material.

[0051] In the scanned RGB image acquisition unit 701, the RGB-LEDs are turned on in sequence, and a scanned RGB image made up of RGB 3ch signal values ​​obtained by converting the light received by the W sensor into digital signals is acquired.

[0052] Here, we will explain the scanned RGB image that is obtained. We consider an original region where fluorescent pink P and non-fluorescent color material Z overlap. The pixel value of the scanned RGB image can be expressed as the sum of the light absorption component and light emission component of fluorescent pink and the light absorption component of non-fluorescent color material Z, as follows:

[0053] R = Za_R + Pa_R + Pb_R G = Za_G + Pa_G + Pb_G B = Za_B + Pa_B + Pb_B Equation 1 a: Light absorbing component b: Luminous component _R, _G, _B: RGB components in each wavelength range The light absorption component takes a negative value, and the light emission component takes a positive value.

[0054] The fluorescent light emission amount acquisition unit 702 acquires the amount of fluorescent light emitted by the excited fluorescent color material. The amount of fluorescent light emission is Pb_R, Pb_G, and Pb_B in formula 1. Specifically, it is a 1ch signal value obtained by converting the light received by the R sensor when the G-LED is turned on into a digital signal. As described above, the fluorescent pink material is excited by light in the wavelength region of the G-LED and emits light in the red region. Therefore, the signal value obtained by receiving light by the R sensor with only the G-LED turned on is the amount of fluorescent light emitted by the excited fluorescent color material. Since the wavelength region of the light received by the sensor due to normal absorption / reflection when the G-LED is turned on is the green region, it is not received by the red sensor. Therefore, when only the G-LED is turned on, the red sensor can extract only the amount of fluorescent light emitted by the excited fluorescent color material. In this way, an image in which the pixel value is the signal value obtained based on the light received by the R sensor when the G-LED is turned on is a 1ch image showing the amount of fluorescent light emission corresponding to the scanned RGB image.

[0055] In the scanned RGB image, all signal values ​​representing the amount of light received by the W sensor when the G-LED is on are added to the G channel, so the amount of fluorescent light emitted by the fluorescent color material excited by light in the green region is also added as Pb_G in formula 1. Similarly, all signal values ​​representing the amount of light received by the W sensor when the R-LED is on are added to the R channel, but since fluorescent pink is hardly excited by light in the red region, Pb_R is considered to be almost zero. All signal values ​​representing the amount of light received by the W sensor when the B-LED is on are added to the B channel, so the amount of fluorescent light emitted by the fluorescent color material excited by light in the blue region is added as Pb_B in formula 1. Alternatively, it can be calculated from the amount of light received by the R sensor when the G-LED is on. It can be calculated from the wavelength of the G-LED, the wavelength of the B-LED, and the excitation intensity due to the excitation wavelength of fluorescent pink.

[0056] The fluorescence absorption estimation unit 703 estimates the fluorescence absorption amount from the fluorescence emission amount. The fluorescence absorption amount is Pa_R, Pa_G, and Pa_B in formula 1. Fluorescent color materials absorb energy, and an amount of excited emission occurs according to the absorbed energy. Therefore, it can be estimated that the fluorescence absorption amount and the fluorescence emission amount are correlated. Therefore, if the fluorescence information showing the excitation-emission relationship of the fluorescent color material is known, the fluorescence absorption amount can be estimated from the fluorescence emission amount. And in the case of fluorescent pink, since the number of fluorescent color materials in practical use is limited, it is possible to prepare their fluorescence information in advance, and the fluorescence absorption amount of the highlighter pen can be estimated from the fluorescence emission amount.

[0057] The estimation of the amount of fluorescence emission and the amount of fluorescence absorption will be described below. In S603, the amount of fluorescence emission is assigned a value between 0 and 100 based on the amount of light received by the Red sensor when the Green-LED emits light, and a 1ch fluorescence image is generated in which the amount of fluorescence emission is the pixel value. The amount of fluorescence emission is set to 0 when there is no light emission, and the value increases as the amount of light increases. The amount of fluorescence emission at a certain pixel is designated FP_l. The amount of fluorescence emission in each channel is calculated from FP_l according to the configuration of the reading device. Here, the amount of fluorescence emission in each channel corresponds to the amount of light in the Red, Green, and Blue wavelength regions.

[0058] The fluorescence absorption amount estimation unit 703 estimates the fluorescence absorption amount from the detected fluorescence emission amount FP_l. To estimate the fluorescence absorption amount, a lookup table (LUT) is used in which the fluorescence emission amount FP_l is input and the corresponding fluorescence absorption amount is defined as an output. FIG. 8 shows an example of the lookup table. Table 1 is the fluorescence emission amount FP_l, which is the input, and is defined by dividing 0 to 100 into 11 stages. Table 2 is a value indicating the fluorescence absorption amount in each RGB channel corresponding to the value of the fluorescence emission amount defined in table 1. For example, when the fluorescence emission amount FP_l=10, the fluorescence absorption amount in the area that realizes the emission amount of "10" is expressed by (R1, G1, B1) for each color component. In the case of a fluorescent pink fluorescent coloring material, the fluorescence absorption amount in the R area is small, the fluorescence absorption amount in the G area is large, and the fluorescence absorption amount in the B area is about intermediate between the two. Additionally, because the G and B regions overlap with the excitation wavelength region of fluorescent pink, the observed fluorescent emission amount fluctuates greatly with increases and decreases in the fluorescent absorption amount in the G and B regions. Therefore, in this table, the values ​​of the fluorescent absorption amounts G1 to G10 and B1 to B10 differ greatly. On the other hand, the R region does not overlap with the excitation wavelength region of fluorescent pink, so the degree of correlation between the fluorescent emission amount and the fluorescent absorption amount is small. Therefore, the values ​​of the fluorescent absorption amounts R1 to R10 are small overall, and do not fluctuate very greatly.

[0059] The image correction unit 704 uses the acquired amount of fluorescence emission and the estimated amount of fluorescence absorption to subtract the fluorescence absorption component values ​​and the fluorescence emission component values ​​from the signal values ​​of each channel at each pixel of the scanned RGB image to generate a corrected RGB image.

[0060] In the above explanation, the calculation of subtraction of the fluorescence absorption component value and the fluorescence emission component value is performed in the RGB signal value, but this is not limited to this. For example, the calculation may be performed in a device-independent color space such as the CIE1976 (L*, a*, b*) color space. In this case, the scanned image may be converted from the device-dependent color space, which is the RGB signal value, to a device-independent color space using the conventionally known sRGB color space definition or adobeRGB color space definition. In that case, table 2 may also store values ​​in the format of variable color difference (L, a, b).

[0061] The output unit 705 reduces color changes caused by the light emission and absorption of the fluorescent color material, and outputs a scanned image close to the color of the original before the fluorescent color material was applied to an output destination device according to the output format specified by the user. If the user's instruction is "copy", print data is created and output to a printer. If the user's instruction is "scan", the image is output to a display device such as a monitor, or to a storage device such as a hard disk.

[0062] Although fluorescent pink has been used as an example of the fluorescent color material, other colors may be used. For example, fluorescent orange may be used. As with fluorescent pink, the amount of fluorescent emission of fluorescent orange can be detected using a G-LED and a red sensor. Furthermore, for example, fluorescent yellow may be used. For fluorescent yellow, the amount of fluorescent emission can be detected by using a B-LED and a green sensor. In any case, other fluorescent color materials may be used as long as light irradiated by an LED having a peak in the visible light region, such as a G-LED or B-LED, acts as excitation light and the fluorescent emission can be detected by a sensor having sensitivity to wavelengths longer than the excitation wavelength.

[0063] In this embodiment, a flatbed scanner is used to read the fluorescent image, but the reading device is not limited to this. Any other reading device may be used as long as it can irradiate a specific light such as green and receive light in a specific wavelength region such as red. For example, the optical sensor 214 provided on the carriage 213 may be provided with a function for reading the fluorescent image. In this case, the scanning for obtaining the scanned RGB image and the scanning for obtaining the amount of fluorescent light are performed by different devices. First, the original is scanned by the reading device 202, which is a flatbed scanner, and the scanned RGB image is obtained by irradiation by the RGB-LED and reception by the W sensor. Next, the same original is fed by the auto sheet feeder of the MFP device 201, and the optical sensor 214 reads it by the reciprocating movement of the carriage 213 to obtain the fluorescent image.

[0064] In this embodiment, RGB LEDs and a W sensor are used to obtain a normal scanned RGB image, but this is not limited to this. RGB LEDs and a sensor that filters the red, green, and blue wavelength regions may be used. In this case, the amount of fluorescent light emitted when the fluorescent coloring material is excited and emits light is filtered by each filter, so it is not added to the read signal value. Therefore, in formula 1, the fluorescent light emission amounts Pb_R, Pb_G, and Pb_B added to the scanned RGB image are almost zero. The fluorescent light absorption amounts Pa_R, Pa_G, and Pa_B are estimated from the fluorescent light emission amounts obtained separately, and the following calculations can be performed in the same manner.

[0065] In addition, in the reading device 202 shown in FIG. 3, a white LED and a green LED may be used as the light source 304, and a sensor equipped with an RGB filter may be used as the sensor 306. FIG. 5(e) shows the light emission characteristics 513 of a standard white LED, and the excitation light 401 and the emission light 402 of a fluorescent pink material. In the case of a scanner using such a white LED, an RGB filter installed on the sensor is generally used to separate the 3 channels of RGB. In FIG. 5(e), the arrows indicate the light receiving sensitivity wavelength ranges 514 to 516 of the sensor with the color filter used in this embodiment. The wavelength range 514 is the light receiving wavelength range of the red sensor, the wavelength range 515 is the light receiving wavelength range of the green sensor, and the wavelength range 516 is the light receiving wavelength range of the blue sensor.

[0066] With the above configuration, when acquiring a normal scan image, the white LED is driven, and the signal value received by the sensor with each color filter becomes the pixel value of the scan image. The excitation light and emission light of the fluorescent pink color material have the same characteristics as those shown in FIG. 4. As shown in FIG. 5(e), the white LED 513 emits light in the entire wavelength range of visible light, and overlaps with the wavelength range of the fluorescent pink excitation light 401, so it can excite the fluorescent pink and cause a luminescence phenomenon. As described above, the wavelength range of the fluorescent pink emission light 402 is the red wavelength range, so it is received by the sensor with a red filter, but not by the sensor with a green filter and blue filter. Therefore, in Equation 1, the fluorescent emission amount Pb_R is the fluorescent emission amount excited by the white LED, and Pb_G and Pb_B are almost zero. In the case of such a device, the fluorescent emission amount can be acquired in the same way as in other embodiments by driving a separately provided green-LED and receiving the fluorescent emission component with a red filter.

[0067] In addition, the recording device for copying has been described as being of an inkjet recording type, but is not limited to this. It may be of an electrophotographic type using powder toner, or a printing device such as an offset printer. The reading device and the recording device do not need to be integrated, and may be a separate reading device that reads and processes the image, and output the processed image from the recording device.

[0068] In addition, in this embodiment, the amount of fluorescent emission and the amount of fluorescent absorption are obtained on a pixel-by-pixel basis for the scanned RBG image, and the color components originating from the fluorescent color material are reduced on a pixel-by-pixel basis. However, a similar process may be performed on a predetermined region basis consisting of multiple pixels.

[0069] Second Embodiment In the first embodiment, the amount of fluorescent light emitted by the fluorescent color material is acquired, the amount of fluorescent light absorption is estimated, and the fluorescent light absorption and emission components of the fluorescent color material are subtracted from the scanned image to reproduce the color of only the non-fluorescent color material. This reduces the color components derived from the fluorescent color material in the scanned image of a document marked with a highlighter pen or the like, making it possible to make the scanned image of the document closer to the image before it was marked with the highlighter pen.

[0070] In the first embodiment, the fluorescence absorption amount is calculated from the measured fluorescence emission amount by utilizing the correlation between the fluorescence absorption amount and the fluorescence emission amount as described above. However, when the fluorescent pink is applied so as to overlap with a coloring material that also absorbs in the emission wavelength range of the fluorescent pink, such as a cyan coloring material, the fluorescence absorption amount cannot be calculated with high accuracy. When the cyan coloring material is overlapped with the fluorescent pink, a part of the emitted light of the fluorescent pink is absorbed by the cyan coloring material, and the fluorescence absorption amount calculated from the measured fluorescence emission amount becomes smaller than the actual fluorescence absorption amount.

[0071] In the second embodiment, the fluorescent pink monochromatic region is referenced to estimate the amount of fluorescent emission and the amount of fluorescent absorption in the mixed color region. Here, the non-fluorescent coloring material to be superimposed on the fluorescent pink is assumed to be a coloring material that does not have a large absorption in the excitation wavelength region of the fluorescent coloring material, but has an absorption in the emission wavelength region of the fluorescent coloring material. In other words, this embodiment is premised on a situation in which there is no large decrease in the amount of fluorescent excitation, but only a large decrease in the amount of fluorescent emission.

[0072] FIG. 9 shows a cross section of a paper surface coated with fluorescent pink color materials 902 and 903 and non-fluorescent color material 904. On the paper surface 901, there is an area 1 coated with fluorescent pink color material 902 in a single color, and an area 2 coated with non-fluorescent color material Z904 and then coated with fluorescent pink color material 903. Both of these are areas marked with fluorescent pink on a document printed using non-fluorescent color material Z904. When marking is performed with a highlighter pen, it is rare to mark only the area coated with color material in the original document, and in most cases, as shown in this figure, an area 2 overlapping with non-fluorescent color material and an area 1 of only fluorescent color material are generated, for example, when marking a black character portion. The area 1 coated with only fluorescent pink, such as area 1, is called a "fluorescent pink single color area," and the area 2 where fluorescent pink overlaps with non-fluorescent color material is called a "secondary color area." Here, the amount of fluorescent pink in the secondary color area is equal to the amount of fluorescent pink in the fluorescent pink single color area. Usually, when marking with a highlighter pen or the like, the amount applied varies slightly depending on the writing pressure, etc., but it is considered to be roughly the same amount applied. In other words, the amount of fluorescent pink material 902 in area 1 and the amount of fluorescent pink material 903 in area 2 are approximately the same.

[0073] In addition, the distinction between region 1 and region 2 is made as follows: a region where the amount of fluorescent light emission is greater than a predetermined first threshold is defined as region 1, and a region where the amount of fluorescent light emission is greater than or equal to a predetermined second threshold which is smaller than the first threshold, but less than the first threshold is defined as region 2.

[0074] First, similarly to the first embodiment, the RGB LEDs of the reader 202 are driven to obtain a normal scanned RGB image.

[0075] The pixel values ​​of region 1, which is a fluorescent pink monochromatic region in the scanned RGB image, can be expressed as the fluorescent absorption component and fluorescent emission component of fluorescent pink P as follows:

[0076] R1 = Pa1_R + Pb1_R G1=Pa1_G+Pb1_G B1=Pa1_B+Pb1_B Formula 2 a: Light absorbing component b: Luminous component _R, _G, _B: RGB components in each wavelength range

[0077] The pixel value of region 2, which is a secondary color where fluorescent pink P and non-fluorescent colorant Z overlap, can be expressed as the sum of the fluorescent absorption component and fluorescent emission component of fluorescent pink and the absorption component of non-fluorescent colorant Z, as in Equation 1 above.

[0078] R2 = Za2_R + Pa2_R + Pb2_R G2 = Za2_G + Pa2_G + Pb2_G B2=Za2_B+Pa2_B+Pb2_B Equation 3 a: Light absorbing component b: Luminous component _R, _G, _B: RGB components in each wavelength range

[0079] In the following description, the _R, _G, and _B used to denote each channel will be omitted.

[0080] Fig. 10 is a diagram for explaining calculation processing blocks in area 2. The same blocks as those explained in Fig. 7 are given the same symbols as in Fig. 7.

[0081] First, the area 2 scan RGB image acquisition unit 1001 acquires an image consisting of pixel values ​​of 3 channels of RGB by a scan operation. The area 2 scan RGB image acquisition unit 1001 drives the mechanism control unit 108 to operate the reading unit 106 under the control of the main control unit 101 in accordance with a copy or scan operation start command accepted by the operation unit. The read scan RGB image is stored in the reading buffer 107.

[0082] Region 2 fluorescence emission amount acquisition section 1002 and region 1 fluorescence emission amount acquisition section 1003 similarly acquire images indicating the fluorescence emission amount by a scanning operation. In this operation, the Green-LED is turned on to scan the original, and the signal value received by the Red sensor is taken as the fluorescence emission amount. Regions 1 and 2 are scanned simultaneously without distinction. From the acquired fluorescence emission amount of region 1, the fluorescence emission amount Pb1 in each channel is calculated in accordance with the configuration of the reading device 202. In region 2, too, the fluorescence emission amount Pb2 is calculated in accordance with the configuration of the reading device 202 from the acquired fluorescence emission amount. The fluorescence emission amount Pb2 in region 2 is the fluorescence emission amount after the luminescent component is absorbed by the non-fluorescent color material Z.

[0083] Region 1 fluorescence absorption amount estimation section 1005 estimates the fluorescence absorption amount Pa1 in region 1 from the acquired fluorescence emission amount Pb1 in region 1. Since the fluorescence absorption amount Pa1 in region 1 is not affected by absorbing luminescent components, it can be assumed that the fluorescence emission amount and the fluorescence absorption amount are correlated, and can be estimated from the fluorescence emission amount Pb1.

[0084] The region 2 fluorescence absorption estimation unit 1004 estimates the fluorescence absorption amount Pa2 in region 2. The fluorescence absorption amount Pa2 in region 2 cannot be estimated from the fluorescence emission amount Pb2 because the luminescent component has been absorbed by the non-fluorescent color material Z. However, since it is assumed that the amount of fluorescent color material on the same paper surface is approximately the same, it is assumed that the same amount of fluorescent color material is applied in both region 1 and region 2. Furthermore, the non-fluorescent color material Z that is overlapped in region 2 absorbs only the luminescent wavelength and does not absorb the excitation wavelength. Therefore, it is considered that it does not affect the absorbed component. Therefore, it can be estimated that the fluorescence absorption amount Pa2 in region 2 is approximately the same as the fluorescence absorption amount Pa1 in region 1.

[0085] 7, the image correction unit 704 uses the acquired amount of fluorescence emission and the estimated amount of fluorescence absorption to subtract the fluorescence absorption components and the fluorescence emission components from the scanned RGB image to generate a corrected scanned RGB image. The corrected scanned RGB image is image data obtained by reducing the color components derived from the fluorescent coloring materials from the scanned RGB image.

[0086] With the above configuration, even in areas where non-fluorescent color materials and fluorescent color materials overlap, the amount of fluorescent absorption can be estimated from the fluorescent monochromatic area, and the fluorescent absorption components and fluorescent emission components can be subtracted from the scanned RGB image, making it possible to approximate the image of the original document before the fluorescent color material was applied.

[0087] (Third embodiment) In the second embodiment, a method for estimating the amount of fluorescence absorption in the secondary color region of the fluorescent color material and the non-fluorescent color material from the amount of fluorescence absorption in the single color region of the fluorescent color material was shown. In this case, the non-fluorescent color material is assumed to be a color material that does not have a large absorption in the excitation wavelength region of the fluorescent color material, but has absorption in the emission wavelength region of the fluorescent color material. In other words, there is no large decrease in the amount of excitation of the fluorescence, and the amount of emission of the fluorescence itself does not decrease.

[0088] In contrast, in this embodiment, we consider a secondary color region with a non-fluorescent coloring material that has absorption in the excitation wavelength region of the fluorescence and also has absorption in the emission wavelength region of the fluorescence. Such a secondary color region is, for example, a region where a color that has absorption in both the excitation wavelength region (green) and the emission wavelength region (red), such as black, overlaps with fluorescent pink.

[0089] As in the second embodiment, the area coated with a single fluorescent pink color is designated as area 1, and the area coated with fluorescent pink and non-fluorescent coloring material in layers is designated as area 2. First, a normal scan is performed to obtain a scanned image consisting of RGB. Next, the amount of fluorescent light emitted in each area is obtained by driving the Green-LED and receiving the light with the Red sensor. From the obtained amount of fluorescent light, the amounts of fluorescent light emitted in each channel Pb1 and Pb2 are calculated using Equation 3.

[0090] Next, the amount of fluorescence absorption is estimated. As in the previous embodiments, the amount of fluorescence absorption Pa1 in region 1 can be estimated by assuming that it is correlated with the amount of fluorescence emission Pb1. The amount of fluorescence absorption Pa2 in region 2 is difficult to estimate from the observed amount of fluorescence emission because it is reduced due to the absorption of fluorescent excitation light by the non-fluorescent color material and the amount of fluorescence emission also decreases.

[0091] Here, as in the second embodiment, if the application amount of the fluorescent coloring material is approximately equal in the regions 1 and 2, it is possible to estimate what color of non-fluorescent coloring material is mixed in, based on the amount of decrease in the amount of fluorescent emission Pb2 in the region 2 relative to the amount of fluorescent emission Pb1 in the region 1. By considering the estimation result of the color of the non-fluorescent coloring material in the region 2, the amount of fluorescent light absorption can be estimated with higher accuracy. The color of the non-fluorescent coloring material is one of the usual cyan, magenta, yellow, and black, or a combination of multiple of these. Although the absorption spectrum varies slightly depending on the coloring material even for the same color, the basic characteristic is the same, for example, that any coloring material of cyan has a large absorption in the red region. Therefore, the absorption spectrum for each color obtained by cyan, magenta, yellow, black, and combinations thereof is prepared in advance, and the amount of fluorescent light absorption considering the absorption by the non-fluorescent coloring material can be estimated. This allows the amount of fluorescent light absorption to be estimated with higher accuracy from the observed amount of fluorescent light emission. (Other Examples) The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions. The present disclosure includes the following configurations and methods. [Configuration 1] a first acquisition means for acquiring a read image obtained by reading an original marked with a fluorescent color material, the read image being composed of pixel values ​​each having a plurality of color components; a second acquisition means for acquiring a fluorescent emission image representing an amount of fluorescent emission obtained by reading the emitted light from the marked portion of the document; a correction means for correcting the read image based on the fluorescent emission image so as to reduce color components derived from the fluorescent color material; An image processing device comprising: [Configuration 2] the correction means estimates an amount of fluorescence absorption in the read image based on the fluorescence image, and corrects the read image based on the fluorescence image and the amount of fluorescence absorption. 2. The image processing device according to claim 1, [Configuration 3] the correction means estimates the amount of fluorescence absorption based on fluorescence information in which the amount of fluorescence emission corresponds to the amount of fluorescence absorption corresponding thereto; 3. The image processing device according to configuration 2. [Configuration 4] the correction means subtracts a value corresponding to the amount of fluorescent light emission and the amount of fluorescent light absorption from the plurality of color components. 4. The image processing device according to configuration 2 or 3. [Configuration 5] the second acquisition means identifies a color of the fluorescent color material in the read image and reads emitted light in a wavelength region corresponding to the identified color; 5. The image processing device according to any one of configurations 1 to 4. [Configuration 6] The emitted light is read when the document is irradiated with light having a wavelength region different from the specified color. 6. The image processing device according to configuration 5. [Configuration 7] The emitted light is read when the document is irradiated with light having a shorter wavelength than the specified color. 6. The image processing device according to configuration 5. [Configuration 8] the correction means estimates the amount of fluorescence absorption in a secondary color region in which a fluorescent color material and a non-fluorescent color material are mixed, based on the amount of fluorescence absorption in a single color region in which only a fluorescent color material is present; 7. The image processing device according to any one of configurations 1 to 6. [Configuration 9] the correction means defines a region where the fluorescence absorption amount is equal to or greater than a first threshold as the monochromatic region, and defines a region where the fluorescence absorption amount is less than the first threshold and equal to or greater than a second threshold that is smaller than the first threshold as the secondary color region. 9. The image processing device according to configuration 8. [Configuration 10] the correction means estimates the amount of fluorescence absorption in the secondary color region based on the amount of fluorescence absorption in the single color region and a reduction in the amount of fluorescence emission in a secondary color region in which a fluorescent color material and a non-fluorescent color material are mixed relative to the amount of fluorescence emission in a single color region containing only a fluorescent color material; 9. The image processing device according to configuration 8. [Configuration 11] 10. The image processing device according to any one of configurations 1 to 9, further comprising an output unit for outputting the corrected read image to a storage device or a printing device. [Configuration 12] A step of acquiring a read image obtained by reading an original marked with a fluorescent color material, in which each pixel has a pixel value having a plurality of color components; obtaining a fluorescent emission image representing an amount of fluorescent emission obtained by reading emitted light from the marked portion of the document; correcting the read image based on the fluorescent emission image so as to reduce color components derived from the fluorescent color material; 13. An image processing method comprising: [Configuration 13] A program for causing a computer to function as the image processing device according to any one of configurations 1 to 11.

Claims

1. a first acquisition means for acquiring a read image obtained by reading an original marked with a fluorescent color material, the read image being composed of pixel values ​​each having a plurality of color components; a second acquisition means for acquiring a fluorescent emission image representing an amount of fluorescent emission obtained by reading the emitted light from the marked portion of the document; a correction means for correcting the read image based on the fluorescent emission image so as to reduce color components derived from the fluorescent color material; An image processing device comprising:

2. the correction means estimates an amount of fluorescence absorption in the read image based on the fluorescence image, and corrects the read image based on the fluorescence image and the amount of fluorescence absorption.

2. The image processing device according to claim 1,

3. the correction means estimates the amount of fluorescence absorption based on fluorescence information in which the amount of fluorescence emission corresponds to the amount of fluorescence absorption corresponding thereto; 3. The image processing device according to claim 2.

4. the correction means subtracts a value corresponding to the amount of fluorescent light emission and the amount of fluorescent light absorption from the plurality of color components.

3. The image processing device according to claim 2.

5. the second acquisition means identifies a color of the fluorescent color material in the read image and reads emitted light in a wavelength region corresponding to the identified color; 2. The image processing device according to claim 1,

6. The emitted light is read when the document is irradiated with light having a wavelength region different from the specified color.

6. The image processing device according to claim 5,

7. The emitted light is read when the document is irradiated with light having a shorter wavelength than the specified color.

6. The image processing device according to claim 5,

8. the correction means estimates the amount of fluorescence absorption in a secondary color region in which a fluorescent color material and a non-fluorescent color material are mixed, based on the amount of fluorescence absorption in a single color region in which only a fluorescent color material is present; 2. The image processing device according to claim 1,

9. the correction means defines a region where the fluorescence absorption amount is equal to or greater than a first threshold as the monochromatic region, and defines a region where the fluorescence absorption amount is less than the first threshold and equal to or greater than a second threshold that is smaller than the first threshold as the secondary color region.

9. The image processing device according to claim 8,

10. the correction means estimates the amount of fluorescence absorption in the secondary color region based on the amount of fluorescence absorption in the single color region and a reduction in the amount of fluorescence emission in a secondary color region in which a fluorescent color material and a non-fluorescent color material are mixed relative to the amount of fluorescence emission in a single color region containing only a fluorescent color material; 9. The image processing device according to claim 8,

11. 11. The image processing apparatus according to claim 1, further comprising an output unit for outputting the corrected read image to a storage device or a printing device.

12. A step of acquiring a read image obtained by reading an original marked with a fluorescent color material, in which each pixel has a pixel value having a plurality of color components; obtaining a fluorescent emission image representing an amount of fluorescent emission obtained by reading emitted light from the marked portion of the document; correcting the read image based on the fluorescent emission image so as to reduce color components derived from the fluorescent color material; 13. An image processing method comprising:

13. A program for causing a computer to function as the image processing device according to any one of claims 1 to 10.

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