JP2014078177A - Image processing device, and control method of the same - Google Patents

Abstract

Even if an image to be printed includes an unusable or difficult to view under normal light and includes an unusable color because it becomes an infrared effect image capable of distinguishing characters and patterns under infrared light, A printed matter that can be expected to have an infrared effect with prior confirmation by the user is obtained.
A corrected image data generation unit 103 rejects a color space reproducible under normal light and a color material having an infrared absorption rate higher than a predetermined value on condition that a color material having an infrared absorption rate higher than a predetermined value is used. A plurality of approximate image data obtained by approximating each pixel value of input image data is generated according to a plurality of algorithms for conversion to a common partial color space that can be reproduced under normal light. The display selection unit 106 displays the generated approximate image data so as to be selectable. The print image data generation unit 108 changes the pixel values of the selected approximate image data according to the latent image data generated by the latent image generation unit 102, and uses a color material that has a high infrared absorption rate, Select one of the colors that do not use a high infrared absorption color and output it.
[Selection] Figure 1

Description

  The present invention relates to a technique for generating a print image that makes a pattern or a character appear on a print medium under infrared light.

  It is easy to use a device that is sensitive to the infrared region, such as an infrared imaging device (infrared camera) under infrared light, as the technology for preventing counterfeiting or authenticating the printed material. There are printing methods that can be recognized.

  As a typical example, a black (k) coloring material used in general printing has a large infrared absorption rate, and there is a method of printing an image using this (Patent Document 1). Print the image on the print medium using black (k), which has a large infrared absorption rate for the latent image area, and cyan (c), magenta (m), and yellow (y), which have a low infrared absorption rate for the background area. . Then, the output print image is irradiated with infrared light, and a character or a pattern is identified by the infrared imaging device. As a result, it is possible to determine whether the printed image is genuine or not if it can be confirmed under infrared light, and whether it is genuine or not.

  As an application of this method, the number of colors that can be used in a printed image is increased by reducing the amount of black (k) in the latent image area and mixing cyan (c), magenta (m), and yellow (y). It is also possible.

Japanese Patent No. 3544536

  However, in the above-described method, the latent image area always includes black (k) having a large infrared absorption rate, so that there are naturally limitations on the colors that can be used for the printed image. For example, when a print image composed of a plurality of colors such as a ticket or an illustration is generated, a color that cannot be used may be included in the print image. In this case, if black (k) having a large infrared absorptance is included in the latent image area, the color difference between the latent image area and the background area increases, and there is a problem that the latent image is visually observed under normal light. To do. Further, conventionally, the user cannot confirm what the printed image will be before printing.

  The present invention has been made in view of the above-described problems, and an infrared effect image in which an image to be printed by a user is not visible or difficult to view under normal light and can identify characters and patterns under infrared light. Therefore, the present invention intends to provide a technique for obtaining a printed matter that can be expected to have an infrared effect even if it contains a color that cannot be used.

In order to solve this problem, for example, an image processing apparatus of the present invention has the following configuration. That is,
An image processing apparatus for generating print image data for printing by a printing apparatus using a plurality of color materials,
Input means for inputting image data to be printed and latent image data that can be identified when imaged by an infrared imaging device;
First color information that defines the amount of each color material used for approximation with the use of a color material having an infrared absorption rate higher than a predetermined value with respect to a target color viewed with normal light, and for the target color Holding means for holding information composed of second color information that defines the amount of use of each color material for approximating that a color material having an infrared absorption rate higher than a predetermined value as unused;
A color space that can be reproduced under normal light under the condition that a color material having an infrared absorption rate higher than a predetermined value is used, and a color space that can be reproduced under normal light without using a color material having an infrared absorption rate higher than a predetermined value. A plurality of color conversion means using different algorithms for approximating each pixel value of the image data input by the input means in a common partial color space with
Image data generation means for generating a plurality of approximate image data by applying the plurality of color conversion means to the image data input by the input means;
Display means for selectively displaying one of the plurality of approximate image data generated by the image data generating means;
Any of the first color information and the second color information held by the holding unit that approximates the color represented by the target pixel of the approximate image data selected by the user among the approximate image data displayed by the display unit. One of these is selected based on a pixel value corresponding to the position of the pixel of interest in the latent image data, and output means for outputting as a pixel value of the print image data.

  According to the present invention, an image to be printed by a user is not visible or difficult to see under normal light, and includes an unusable color because it becomes an infrared effect image that can distinguish characters and designs under infrared light. Even if it is, it is possible to obtain a printed matter that can be expected to have an infrared effect under the prior confirmation of the user.

The system block diagram in this embodiment. , , , , 6 is a flowchart illustrating print image generation processing according to the first embodiment. The figure which shows the concept of a printed image. The figure which illustrates image data and latent image image data. The figure which shows each color gamut of the 1st area | region and 2nd area | region in CIE L * a * b * space. The figure which illustrates latent image image data. The figure which illustrates correction image data. The figure which illustrates color information. The figure which illustrates a printed image. The figure which illustrates the display of correction image data. The block diagram which shows the basic composition of the computer system in this embodiment.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

[First Embodiment]
First, the basic concept in the present embodiment will be briefly described with reference to FIG. The print medium 1001 cannot be identified as shown in FIG. 3A under normal light (for example, D50, which is a colorimetric light whose relative spectral distribution is defined by the CIE (International Commission on Illumination)) as shown in FIG. To make it easier to understand.) However, when viewed with a special identification device such as an infrared imaging device under infrared light, as shown in FIG. 3B, a printed image 300 in which characters (or patterns, marks) are manifested is formed. In the illustrated example, the print image 300 includes a latent image area called “Original” and a non-latent image area (hereinafter referred to as a background area). The circular range 303 is an enlarged portion of the last character “l” of the character string “Original”. As a result, it is possible to determine whether the printed material is genuine or not if it can be confirmed under infrared light.

  In FIG. 3C, the print medium 1001 includes a background area 301 made of a color material having a low infrared absorption rate and a latent image area 302 made of a color material having a high infrared absorption rate. It is a figure.

  When this print medium is irradiated with infrared light IR, as shown in FIG. 3C, the background region 301 reflects infrared light IR because the infrared absorption rate is small, and the latent image region 302 has infrared absorption rate. Since it is large, it absorbs infrared light IR.

  When this is viewed with an infrared imaging device, the brightness of the background area 301 becomes brighter as shown in FIG. 3D, whereas the brightness of the latent image area 302 becomes darker.

  Of cyan (c), magenta (m), yellow (y), and black (k) color materials used in general printing equipment (printers), black (k) is a black color mainly composed of carbon black. The material has a large infrared absorption rate. On the other hand, cyan (c), magenta (m), and yellow (y) are known to have a low infrared absorptance.

  Therefore, if the latent image area is configured by black (k) and the background area 301 is configured by cyan (c), magenta (m), and yellow (y) so that the color is similar to the latent image area, the above-described printing is performed. The image 300 can be generated.

  The fact that the print image 300 can be identified under infrared light means that, as a result, only one of the background region 301 and the latent image region 302 needs to contain a color material having a large infrared absorption rate. In other words, it means intentionally creating two regions with different infrared absorption rates.

  Accordingly, the background area 301 may be composed of cyan (c), magenta (m), and yellow (y), and the latent image area may be composed of cyan (c), magenta (m), yellow (y), and black (k). The print image 300 described above can be generated.

  In the following, the background area 301 is represented by a combination of cyan (c), magenta (m), and yellow (y) under the condition that black (k) is not used. The case where the latent image area is represented by a combination of cyan (c), magenta (m), yellow (y), and black (k) under the condition that black (k) is always used will be described. .

  5 (a) and 5 (b) are composed of cyan (c), magenta (m), and yellow (y), and the latent image areas are cyan (c), magenta (m), yellow (y), Each color gamut that can be expressed when composed of black (k) is expressed in CIE L * a * b * space. Approximating the color of the background area and the color of the latent image area under normal light means using a color that can express both the background area and the latent image area. In other words, color space 500 that can be reproduced under normal light without using a color material having an infrared absorption rate higher than a predetermined value, and reproduction under normal light on condition that a color material having an infrared absorption rate higher than a predetermined value is used. A partial color space 502 common to the possible color space 501 is a color gamut that can be used for a print image.

  However, since black (k) having a high infrared absorption factor must be included in the latent image area, there are limitations on the colors (shaded portions in the figure) that can be used for the printed image. That is, the color of the area where the color gamut of the background area and the latent image area do not overlap becomes a color that cannot be used for the print image.

  In other words, the color that can be used for the print image has a small color difference between the color of the background region and the color of the latent image region, and the color that cannot be used for the print image has a large color difference between the color of the background region and the color of the latent image region.

  Here, for example, as shown in FIG. 4 (a), based on image data composed of one pixel value (R2, G2, B2), when viewed with an infrared imaging device by irradiating infrared light, FIG. As shown in (b), let us consider generating a print image in which characters become obvious.

  The pixel values (R2, G2, B2) are represented by the points in FIG. 5A in the CIE L * a * b * space, and the color of the area where the color gamut of the background area and the latent image area do not overlap, That is, it is assumed that the color cannot be used for the print image.

  In this case, black (k) having a large infrared absorption rate cannot be included in the latent image region. If black (k) with a large infrared absorption rate is included, the color of the latent image area will be different from the color of the pixel values (R2, G2, B2) to be expressed, and the color of the background area The color difference between the colors in the image area increases. As a result, there is a problem that the latent image can be visually observed under normal light.

  Therefore, in the present embodiment, the print image is generated by reducing the luminance of the color of the print image or by replacing it with a usable color that has a small color difference between the color of the background area and the color of the latent image area.

  For example, the pixel values (R1, G1, B1) are represented by the points in FIG. 5A in the CIE L * a * b * space, and the color of the region where the color gamut of the background region and the color gamut of the latent image region overlap. That is, it is assumed that the print image has a usable color. In addition, the pixel values (R4, G4, B4) are represented by the points in FIG. 5A in the CIE L * a * b * space, and are colors in which the luminance of the pixel values (R2, G2, B2) is reduced. And

  At this time, the colors that cannot be used in the printed image (pixel values (R2, G2, B2)) are expressed with the colors that can be used with reduced brightness (pixel values (R4, G4, B4)), or the color difference is approximate. The colors can be used (pixel values (R1, G1, B1)).

  In addition, by combining the above two methods, it is possible to reduce the luminance and to express the colors (pixel values (R5, G5, B5)) that can be used with color difference approximation.

  Hereinafter, in the present embodiment, an example in which a color material having a large infrared absorption rate is used for the latent image region will be described. However, it is obvious that the background material and the latent image region can be reversed, that is, a color material having a large infrared absorption rate can be applied to the background region.

<Print image generation method>
Hereinafter, specific processing until the image processing apparatus generates a print image will be described. FIG. 1 is a block diagram showing a functional configuration of an image processing apparatus according to the present embodiment.

  As shown in FIG. 1, the image processing apparatus 11 is an apparatus that can generate a print image.

  The image input unit 101 has a function of reading or generating image data that is electronic data to be printed. The latent image generation unit 102 has a function of reading latent image data that is electronic data and generating a latent image. The generation source of the image data input by the image input unit is, for example, an image scanner, but the generation source is not limited as long as it is image data in a processable electronic data format. Also, the latent image generation unit 102 only needs to be finally binary image data. For example, the latent image generation unit 102 may generate the image by reading a document as a binary image from an image scanner, or may generate a character from a character code. Since a binary image in which a pattern is generated may be generated, the type of generation source is not limited.

  The corrected image data generation unit 103 has a function of correcting (color conversion) the color of the original image data from the image input unit 101 according to a plurality of different algorithms and generating a plurality of corrected image data (approximate image data). . In the corrected image data, the color-reduced image data in which the color of the original image data is changed to the color of the palette information selected by the color information selection unit 105, the brightness-changed image data in which the brightness of the image data is changed, and the color of the changed image data It includes three pieces of brightness-changed reduced-color image data that have been changed to the palette information color.

  The threshold value holding unit 104 has a function of holding a color difference threshold value when selecting color information. This threshold value can be changed by the user from an operation unit (not shown).

  The color information selection unit 105 acquires color information from the color information holding unit 107, selects color information based on the color difference threshold value held in the threshold value holding unit 104, and selects each selected color information item. It has a function to generate as palette information.

  The display / selection unit 106 has a function of displaying a plurality (three in the embodiment) of corrected image data generated by the corrected image data generation unit 103 and allowing the user to select desired image data.

  The color information holding unit 107 holds, as a table, color information indicating the usage amounts of the recording colors of the first color and the second color, which have different infrared absorption rates, with respect to the color to be developed on the print medium. It has the function to do.

  The color information is a color to be developed on the print medium, for example, a color material similar to the pixel value (RGB value) of the image data. Is information indicating how much (hereinafter referred to as color material usage) is formed. As shown in FIG. 8, the color information table has a color material usage amount (first color) representing the first color used in the background region for one input pixel value (a target color viewed under normal light). Color information), a color material usage amount (second color information) representing the second color used in the latent image area, and a color difference value ΔEab which is a difference value between the first and second pixel values with respect to the input pixel value. Consists of.

  Note that the colors that can be used for the print image have a small color difference between the background area color and the latent image area color, and the colors that cannot be used for the print image have a large color difference between the background area color and the latent image area color. .

  Here, for each RGB value, the ratio of each color material, where the maximum amount of color material per unit area that adheres to the print medium is 100, is shown as a numerical value.

  Note that the color information is held in advance for all pixel values used in the image data.

  The print image data generation unit 108 has a function of generating data constituting a print image from the corrected image data, the latent image data, and the color information.

  The output unit 109 has a function of taking paper and printing the print image on the paper based on the print image data.

  Hereinafter, a method for realizing the present embodiment will be described with reference to the block diagram of the image processing apparatus 11 in FIG. 1 and the flowchart in FIG. 2A.

  First, when image data is input to the image processing apparatus 11, the image input unit 101 reads the image, generates image data I as electronic data (S 201), and supplies the image data I to the corrected image data generation unit 103. . Here, the image data I is an image that can be handled in units of pixels. For example, when the image is a paper document, the image input unit 101 includes a charge coupled device CCD or an optical sensor, and performs image capturing, electrical signal processing, digital signal processing, and the like in accordance with an image input instruction to perform image data I Is generated. If the image is data described in a page description language or data created by an application that handles a specific data format, the data format is a general image format (bitmap format, etc.). Into image data I. Here, in order to simplify the description, the generated image data I is a uniform color image, that is, all pixels are configured with the same pixel values (R2, G2, B2) as shown in FIG. Shall be.

  Next, when the latent image data C representing a pattern or a character to be made visible under infrared light is input, the latent image generation unit 102 generates latent image data Ic and print image data generation unit 108. (S202).

  Here, the latent image data Ic is binary image data that can be handled in units of pixels, and the pattern or character portion is “1”, and the others are “0”. In other words, it can be said that the latent image data Ic is composed of information indicating whether each pixel is the background region or the latent image region described above.

  When the latent image data C is composed of characters “Original” as shown in FIG. 4B, binary image data in which the pixels of the latent image portion are “1” and the other pixels are “0” The latent image data Ic. Here, when the latent image data C is a binary image, the latent image data Ic is used as it is. However, in the case of drawing information for drawing a picture or a character, a binary image is generated based on the drawing information. This is set as latent image data Ic.

  Note that the size of the print image is the same as that of the input image data I. For this reason, the sizes of the image data I and the latent image data Ic may be different. Now, assuming that the size of the latent image data Ic is smaller than the size of the image data I, for example, the latent image data Ic is generated by enlarging as shown in FIG. Further, the latent image data Ic may be created by repeating the latent image data Ic as shown in FIG. If the size of the latent image data Ic is larger than the size of the image data I, the image is reduced as shown in FIG.

  Next, when the image data I is acquired from the image input unit 101, the corrected image data generation unit 103 generates brightness-changed image data Ib in which the brightness of the image data is changed (S203). Further, the corrected image data generation unit 103 changes the color of the image data I to the color of the palette information selected by the color information selection unit 105, and the color of the brightness changed image data Ib to the color of the palette information. The changed luminance change reduced color image data Ibr is generated (S204).

  Then, the three data of the luminance change image data Ib, the reduced color image data Ir, and the luminance change reduced color image data Ibr are supplied to the display / selection unit 106 as corrected image data.

  In the following, the process of generating the luminance change image data Ib, the luminance change subtractive color image data Ibr, and the subtractive color image data Ir, which are correction image data, will be sequentially described.

  For the sake of brevity, the following description focuses on the area indicated by reference numeral 401 in FIG. 4A and the area indicated by reference numeral 402 in FIG. 4B.

  FIG. 7 (a) shows an enlarged view of the area 401 in FIG. 4 (a), and FIG. 7 (b) shows an enlarged view of the area 402 in FIG. 4 (b).

  First, the generation process (first conversion process) of the brightness change image data Ib will be described with reference to the flowchart of FIG. 2B.

  When the corrected image data generating unit 103 acquires the original image data I from the image input unit 101, the corrected image data generating unit 103 calculates the luminance value of each pixel of the original image data I (S212).

The luminance component value Y is calculated using the following generally known formula (note that the small letter y indicates yellow, which should be noted).
Y = 0.299 * R + 0.587 * G + 0.114 * B

  The corrected image data generation unit 103 calculates the luminance value of each pixel, detects it as the highest luminance value Yh (maximum luminance value Yh) in the image data I, and holds it.

  Next, the corrected image data generation unit 103 determines that the color difference held by the color information holding unit 107 to the threshold holding unit 104 is less than or equal to the threshold value (this threshold value has already been described by the user). The color information of the highest luminance value is acquired (S213). This refers to the color information in order from the top, finds the color information below the threshold, calculates the luminance value using the above formula for the color information below the threshold, and determines the highest luminance value as Ych (maximum luminance value). Ych).

Next, the difference between the maximum luminance values Yh and Ych in the image data I is calculated, and this is set as the change amount D (S214).
D = Yh-Ych
Then, paying attention to the change amount D, if the change amount D> 0, the luminance value is changed for each pixel of the image data I (S216).

In the luminance value change, the luminance value of each pixel is calculated, changed by the change amount D from the luminance value, and reconverted into RGB again. If the target pixel is (R_a, G_a, B_a) and the pixel after the luminance change is (R_b, G_b, B_b), the conversion may be calculated according to the following equation.
Y = 0.299 * R_a + 0.587 * G_a + 0.114 * B_a
Cr = 0.500 * R_a -0.419 * G_a -0.081 * B_a
Cb = -0.169 * R_a -0.332 * G_a + 0.500 * B_a
R_b = (YD) + 1.402 * Cr
G_b = (YD) -0.714 * Cr-0.344 * Cb
B_b = (YD) + 1.772 * Cb
That is, processing for lowering the luminance value of each image by the change amount D is performed.

  As described above, the luminance value is changed, and it is determined whether or not all pixels have been completed (S217).

  If unprocessed pixels still remain, the target pixel is changed (S218). On the other hand, when the processing of all the pixels is completed, the finally generated luminance changed image data Ib is output (S219).

  For example, if the pixel of the image data I is (R2, G2, B2) as shown in FIG. 7A, the luminance value is calculated, and the changed pixel is (R4, G4, B4), Changed image data Ib as shown in FIG. 7 (c) is generated.

  If the change amount D is D <0 (0 or less), the image data I is output as the brightness change image data Ib without changing the brightness (S219). If the amount of change D is D <0, there is a high possibility that all the pixels of the image data I are colors in the area where the color gamut of the background area overlaps the color gamut of the latent image area, that is, a color that can be used for the print image This is because there is no need to change the luminance value.

  Heretofore, the generation processing of the brightness change image data Ib has been described.

  Next, generation processing (second conversion processing) of luminance change subtractive color image data Ibr will be described with reference to the flowchart of FIG. 2C. The luminance change subtractive color image data Ibr is generated from the luminance change image data Ib.

  The corrected image data generation unit 103 acquires the color information from the color information holding unit 107 (S220), selects the color information based on the color difference threshold held by the threshold holding unit 104, and is selected. Each color information is generated as palette information Cp (S221).

  FIG. 8 shows color information, and color information below a threshold value Th is selected from this color information. The selected color information becomes the palette information Cp. For example, when the threshold value Th = 2, the palette information Cp is a set of colors represented by colors having a color difference of 2 or less, that is, Cp = {(R1, G1, B1), (R5, G5, B5),.・}.

  In this way, palette information Cp with color information selected is generated. Then, based on the palette information Cp, paying attention to the first pixel of the brightness changed image data Ib, the colors of the pixels of the brightness changed image data Ib are compared (S222). If the color of the pixel of the brightness changed image data Ib is the same as the color of the palette information Cp, it is determined whether or not all pixels have been completed for the brightness changed image data Ib without changing the color (S225). If all the pixels have not been completed, the target pixel is changed (S226), and the processing after step S222 is performed.

  If the color of the pixel of the brightness change image data Ib is different from the color of the palette information Cp, the closest color information is selected from the palette information Cp, and the color of the pixel is changed (S224). It is assumed that the color is changed by error diffusion when changing.

  For example, the pixel value (R4, G4, B4) = (128, which added the error diffused from the pixel (4) processed before the target pixel to the target pixel value (R2, G2, B2) 0,128), and the color information of the closest color in the palette information Cp with respect to (R4, G4, B4) is (R5, G5, B5) = (128,0,64). The error generated at this time is distributed to unprocessed pixel positions according to the distribution ratio in the error diffusion matrix of FIG. Note that if the pixel of interest is the first pixel of the image (generally, the pixel in the upper left corner of the image is processed in the raster scan order), the error that occurred before that is considered to be zero.

  The error derived from the pixel of interest is distributed to other unprocessed pixel positions in accordance with the error diffusion matrix shown in FIG.

In an embodiment,
Pixel value of interest 701 (R5, G5, B5) = (128,0,64)
The error is distributed to the relatively adjacent unprocessed pixel positions 702, 703, 704, and 705 as follows.
Pixel 702 = (+ (R4-R5) * 7/16, + (R4-R5) * 7/16, + (R4-R5) * 7/16)
Pixel 703 = (+ (R4-R5) * 3/16, + (R4-R5) * 3/16, + (R4-R5) * 3/16)
Pixel 704 = (+ (R4-R5) * 5/16, + (R4-R5) * 5/16, + (R4-R5) * 5/16)
Pixel 705 = (+ (R4-R5) * 1/16, + (R4-R5) * 1/16, + (R4-R5) * 1/16)
In the embodiment, since the error diffusion matrix shown in FIG. 7E is used, a buffer memory that holds the distributed error value is sufficient if it has a capacity of 1 line + 1 pixel.

  Now, after the color of the pixel has been changed, it is determined whether or not all pixels have been completed for the luminance-changed image data Ib (S225). If all the pixels have not been completed, the target pixel is changed (S226), and the processing after step S222 is performed.

  On the other hand, when all the pixels have been processed, the finally generated luminance-changed color-reduced image data Irb is output (S227).

  For example, assuming that the pixels of the brightness changed image data Ib are (R4, G4, B4) as shown in FIG. 7C and the changed pixels are (R5, G5, B5), FIG. As shown in FIG. 4, luminance-changed subtractive color image data Ibr is generated. It should be noted that the luminance change subtractive color image data Ibr is composed of color information (R1, G1, B1) and (R5, G5, B5) of the palette information Cp.

  In addition, although the method of selecting and generating color information of the threshold value Th or less from the color information for the palette information Cp has been described this time, the present invention is not limited to this. For example, the number of colors to be selected can be set in advance, the color information can be divided into sections from the set number of colors, and the color information having the smallest color difference in the section can be selected as the palette information Cp.

  For example, when the number of colors is 512 and the color information is divided into 512 pieces, the smallest color difference in section 1 is (R1, G1, B1) as shown in FIG. 8 (R1, G1, B1). Is selected. The palette information Cp is generated by performing the same processing for all 512 sections in this way.

  In the foregoing, the generation process of the changed color-reduced image data Ibr has been described. The reduced color image data Ir can be generated by performing the above-described generation process on the image data I, and thus detailed description thereof is omitted.

  In this way, the brightness change image data Ib, the reduced color image data Ir, and the brightness change reduced color image data Ibr are generated, and these three data are supplied to the display / selection unit 106 as corrected image data.

  Next, when the corrected image data is supplied from the corrected image data generation unit 103, the display / selection unit 106 displays each image data (three in the embodiment) of the corrected image data, and one image among them is displayed. The user is made to select data (S205).

  Here, a method of displaying and selecting the corrected image data will be described in detail with reference to the flowchart of FIG. 2D and the diagram illustrating the display method of FIG.

  When the corrected image data is supplied from the corrected image data generation unit 103, the display / selection unit 106 can select corrected image data (changed image data Ib, reduced color image data Ir, and changed reduced color image data Ibr in the embodiment). It is displayed (S228).

  FIG. 10A is a diagram illustrating a display method, in which changed image data Ib, reduced color image data Ir, and changed reduced color image data Ibr, which are corrected image data, are displayed.

  Next, the user selects one image data to be printed from the displayed corrected image data (changed image data Ib, reduced color image data Ir, and changed reduced color image data Ibr) (S229).

  For example, as shown in FIG. 10A, a check box is provided above each image data, and desired image data can be selected by turning on the check box of the image data to be selected.

  Then, when the user selects printing after selecting the image data, the selected image data is supplied to the print image data generation unit 108 as corrected image data (S230). In the case where printing is not performed, the process ends by selecting cancel.

  In addition, the above-described display / selection method is a method of displaying and selecting the changed image data Ib, the reduced color image data Ir, and the changed reduced color image data Ibr at a time, but a method of sequentially displaying and selecting them is also conceivable. . The processing in this case will be described with reference to the flowchart of FIG. 2E and the display examples of FIGS. 10B, 10C, and 10D.

  When the corrected image data is supplied from the corrected image data generation unit 103, the display / selection unit 106 first displays the luminance change subtractive color image data Ibr that is the corrected image data (S231).

  FIG. 10B is a diagram illustrating a display method, in which changed color-reduced image data Ibr that is corrected image data is displayed.

  Next, the user determines whether the displayed changed color-reduced image data Ibr is image data to be printed (S232). Whether or not printing is desired is selected by a “Yes” / “No” button as shown in FIG. If “Yes” is selected for printing, the display / selection unit 106 supplies the changed color-reduced image data Ibr as corrected image data to the print image data generation unit 108 (S233).

  When not printing, that is, when “No” is selected, the changed image data Ib is displayed as shown in FIG. 10C (S234).

  Then, the user determines whether the displayed changed image data Ib is image data to be printed (S235).

  When “Yes” is selected for printing, the display / selection unit 106 supplies the changed image data Ib to the print image data generation unit 108 as corrected image data (S236).

  When printing is not performed, that is, when “NO” is selected, the color-reduced image data Ir is displayed as shown in FIG. 10D (S237).

  Then, the user determines whether or not the displayed reduced color image data Ir is image data to be printed (S238).

  If “Yes” is selected for printing, the display / selection unit 106 supplies the reduced color image data Ir as corrected image data to the print image data generation unit 108 (S239).

  If it is desired to display again, when “display again from the beginning” is selected, the process returns to step S231 and the above-described processing is similarly performed.

  When printing is not performed, that is, when “No” is selected, the processing is terminated.

  The method for displaying and selecting the corrected image data has been described above. Although the display order of the corrected image data this time is displayed in the order of changed subtractive color image data, changed image data, and subtractive color image data, the present invention is not limited to this, and any image data may be displayed.

  Next, returning to the flowchart of FIG. 2A, a method for generating a print image will be described.

  When the corrected image data is supplied from the display / selection unit 106, the print image data generation unit 108 reads color information as shown in FIG. 8 from the color information holding unit 107, and corrects the corrected image data (changed image data Ib, reduced color image). Attention is paid to the first pixel of either the data Ir or the changed color-reduced image data Ibr) and the latent image data Ic. Then, the subsequent processing is switched depending on the value of the focused pixel in the latent image data Ic (S206). It is assumed that the changed color-reduced image data Ibr is selected as the corrected image data by the display / selection unit 106 described above.

  First, when the value of the latent image image data Ic is “1”, the color information held by the color information holding unit 107 is referred to, and the pixel value of the focused color-changed image data Ibr of the pixel of interest is corresponded. Of the color material usage amount, “color of latent image area” is set as print image data (S207).

  For example, if the pixel value of the modified image data Ib is (R5, G5, B5), it is the color of the latent image area of (R5, G5, B5) (C, M, Y, K) = (28, 23, 28,5) is the print image data.

  Referring to FIG. 8, the color material usage amount of the color material (K) having a large infrared absorption rate of “color of latent image region” is “5”, and the color material (K) having a large infrared absorption rate. Note that this is included.

  Then, when the value of the latent image data Ic is “0”, the color information held by the color information holding unit 107 is referred to and corresponds to the pixel value of the changed color-reduced image data Ibr of the pixel of interest. Of the color material usage amount, “background area color” is set as print image data (S208).

  For example, if the pixel value of the changed color-reduced image data Ibr is (R5, G5, B5), it is the color of the background area of (R5, G5, B5) (C, M, Y, K) = (30, 25, 30,0) is the print image data. In FIG. 8, the color material usage amount of the color material (K) having a large infrared absorption rate of “background area color” is “0”, and the color material (K) having a large infrared absorption rate is Note that it is not included.

  Then, it is determined whether or not all the pixels have been processed (S209). If there are still unprocessed pixels, the target pixel is changed (S210). On the other hand, when all the pixels have been processed, the output unit 109 prints the print image on the print medium based on the finally generated print image data (S211).

  For example, when the changed color-reduced image data Ibr shown in FIG. 7D and the latent image data Ic shown in FIG. 7B are used, a print image as shown in FIG. 7F is generated. It should be noted that the pixel 706 corresponding to the latent image region uses “color of the latent image region” and includes a color material (K) having a large infrared absorption rate.

  When the above processing is performed in FIG. 4 (a), the printed image looks as shown in FIG. 9 (a) under normal light, and when viewed with an infrared imaging device by irradiating infrared light, FIG. ).

  The specific processing until the generation of the print image has been described above using the block diagram and the flowchart.

  In the present embodiment, the corrected image data selected by the display / selection unit 106 has been described as changed color-reduced image data, but the present invention is not limited to this. That is, when the reduced color image data Ir or the changed image data Ib is selected, the process after step S206 is similarly performed on the reduced color image data Ir or the changed image data Ib to generate a print image.

  As described above, according to the first embodiment, the user can confirm the print image in advance, and even when a color that cannot be used is included in the print image, it is difficult to visually recognize the image under normal light. It is possible to generate a printed image in which characters or designs can be identified under light.

[Second Embodiment]
In the second embodiment, each process according to the first embodiment is realized by an application executed on an information processing apparatus represented by a personal computer.

  FIG. 11 is a diagram illustrating a basic configuration of an information processing apparatus (computer). For example, when all functions are executed in this computer, all the functions of the first embodiment can be realized on this computer by expressing each function configuration by a program and causing the computer to read it.

  In the figure, reference numeral 1101 denotes a CPU, which controls the entire computer using programs and data stored in a RAM 1102 and a ROM 1103 and performs each process described in the above embodiment.

  Reference numeral 1102 denotes a RAM which has an area for temporarily storing programs and data loaded from the external storage device 1108 and programs and data downloaded from other computer systems 1114 via an I / F (interface) 1115. The CPU 1101 includes an area necessary for performing various processes.

  Reference numeral 1103 denotes a ROM which stores computer function programs and setting data. Reference numeral 1104 denotes a display control apparatus, which performs control processing for displaying images, characters, and the like on the display 1105. Reference numeral 1105 denotes a display that displays images, characters, and the like. As a display, a CRT or a liquid crystal screen can be applied.

  An operation input device 1106 is configured by a device that can input various instructions to the CPU 1101 such as a keyboard and a mouse. Reference numeral 1107 denotes an I / O for notifying the CPU 1101 of various instructions input via the operation input device 1106.

  Reference numeral 1108 denotes an external storage device that functions as a large-capacity information storage device such as a hard disk, and stores an OS (Operating System), a program for causing the CPU 1101 to execute processing according to each of the above embodiments, input / output original images, and the like. Writing information to the external storage device 1108 and reading information from the external storage device 1108 are performed via the I / O 1109.

  Reference numeral 1110 denotes a printer for outputting documents and images. Output data is sent from the RAM 1102 or the external storage device 1108 via the I / O 1111. Examples of printers for outputting documents and images include ink jet printers, laser beam printers, thermal transfer printers, and dot impact printers.

  Reference numeral 1112 denotes a scanner for reading a document or an image. Input data is sent to the RAM 1102 or the external storage device 1108 via the I / O 1113.

  Reference numeral 1116 denotes a bus connecting the CPU 1101, ROM 1103, RAM 1102, I / O 1111, I / O 1109, display control device 1104, I / F 1115, I / O 1107, and I / O 1113.

  In the above configuration, the CPU 1001 functions as each component in FIG. 1 by a program executed by the CPU 1101. Note that the second embodiment can be applied not only to an image editing application but also to a printer driver. When applied to a printer driver, it is conceivable to generate and print a latent image represented by license information of a printer to be used.

  In the present embodiment, processing other than scanning and printer is performed by a computer. However, processing performed by a computer may be performed by using a dedicated hardware circuit inside a scanner or printer.

  Each of the above-described embodiments is merely a specific example for carrying out the present invention, and the technical scope of the present invention should not be construed in a limited manner. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

  In the embodiment, since the member that absorbs a large amount of infrared light is carbon, a CMYK color space including black (k) that reproduces black alone and a CMY color space that reproduces black in C, M, and Y. However, the present invention is not limited to the above-described embodiment, as long as it can express a color material having a large infrared absorption degree in combination with other color materials.

  Further, in the embodiment, as the corrected image data presented to the user, the brightness change image data Ib, the brightness change color reduction image data Ibr, and the color reduction image data Ir are exemplified, but the present invention is not limited thereto. In short, there is a color space that can be reproduced under the condition that a predetermined amount of color material (a ratio of 5 to 100 in the embodiment) is always used, and a color space that can be reproduced without using a high infrared absorption rate. A sample image obtained by approximating the original color space by some methods may be displayed and selected in the shared partial color space.

(Other examples)
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

Claims (8)

An image processing apparatus for generating print image data for printing by a printing apparatus using a plurality of color materials,
Input means for inputting image data to be printed and latent image data that can be identified when imaged by an infrared imaging device;
First color information that defines the amount of each color material used for approximation using a color material having an infrared absorption rate higher than a predetermined value with respect to a target color viewed with normal light, and for the target color Holding means for holding information composed of second color information that defines the amount of use of each color material for approximating that a color material having an infrared absorption rate higher than a predetermined value as unused;
A color space that can be reproduced under normal light under the condition that a color material having an infrared absorption rate higher than a predetermined value is used, and a color space that can be reproduced under normal light without using a color material having an infrared absorption rate higher than a predetermined value. A plurality of color conversion means using different algorithms for approximating each pixel value of the image data input by the input means in a common partial color space with
Image data generation means for generating a plurality of approximate image data by applying the plurality of color conversion means to the image data input by the input means;
Display means for selectively displaying one of the plurality of approximate image data generated by the image data generating means;
Any of the first color information and the second color information held by the holding unit that approximates the color represented by the target pixel of the approximate image data selected by the user among the approximate image data displayed by the display unit. An image processing apparatus comprising: an output unit that selects either one based on a pixel value corresponding to a position of the target pixel in the latent image data and outputs the selected pixel value as the pixel value of the print image data. The holding unit further holds a difference value between a color that can be reproduced with the first color information and the second color information and a color of the target color,
The plurality of color conversion means include
First conversion means for converting a luminance component;
A second color value that is converted into one closest to the color represented by the pixel of interest of the image data input by the input means, out of the target colors having the difference value held by the holding means equal to or less than a preset threshold value; The image processing apparatus according to claim 1, further comprising: The first conversion means includes
Detecting means for detecting the maximum brightness value Yh in the image data to be printed input by the input means, and detecting the maximum brightness value Ych when the difference value held by the holding means is less than or equal to a preset threshold value; ,
The difference between the maximum luminance values Yh and Ych detected by the detection means is obtained as a change amount D by the following equation,
D = Yh-Ych
When the change amount D is larger than 0, a result obtained by subtracting the change amount D from the luminance component value of each pixel value in the image data to be printed input by the input unit is output, and the change amount D is 0 or less. 3. The image processing apparatus according to claim 2, further comprising: a brightness changing unit that directly outputs the image data to be printed input by the input unit as a result of the conversion.   The second conversion unit refers to a matrix indicating a preset distribution ratio with respect to the difference between the color represented by the pixel of interest of the image data input by the input unit and the color after conversion, and performs unprocessed processing. The image processing apparatus according to claim 2, further comprising a distribution unit that distributes the pixel positions. The color material is cyan, magenta, yellow, black,
The image processing apparatus according to claim 1, wherein the color material having an infrared absorption rate higher than a predetermined value is black. First color information that defines the amount of each color material used for approximation using a color material having an infrared absorption rate higher than a predetermined value with respect to a target color viewed with normal light, and for the target color A plurality of color materials having holding means for holding information composed of second color information that defines a use amount of each color material for approximating that a color material having an infrared absorption rate higher than a predetermined value as unused; A control method for an image processing apparatus for generating print image data for printing by a printing apparatus using
An input step for inputting image data to be printed and latent image data that can be identified when captured by an infrared imaging device;
Each of a plurality of color conversion means of different algorithms has a color space that can be reproduced under normal light and a color material with an infrared absorption rate higher than a predetermined value under the condition that a color material having an infrared absorption rate higher than a predetermined value is used. A plurality of color conversion steps for approximating each pixel value of the image data input in the input step to a common partial color space with a color space reproducible under normal light as usage;
An image data generation unit that generates a plurality of approximate image data by applying the plurality of color conversion steps to the image data input in the input step;
A display step in which display means displays one of the plurality of approximate image data generated in the image data generation step in a selectable manner;
The output means approximates the color represented by the target pixel of the approximate image data selected by the user from the approximate image data displayed in the display step, the first color information held by the holding means, the second color information An output step of selecting any one of the color information based on a pixel value corresponding to the position of the pixel of interest in the latent image data and outputting the selected pixel value as the pixel value of the print image data. A method for controlling a processing apparatus.   A program for causing a computer to function as the image processing apparatus according to claim 1 by being read and executed by a computer.   A computer-readable storage medium storing the program according to claim 7.