JP2011097196A - Apparatus and method for processing color - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve correct color reproduction under an optional observation environment for a sample containing a phosphorous component at a small amount of data. <P>SOLUTION: A color processing apparatus, which calculates a spectral reflectance including a phosphorous component of a sample in a target light source, includes an obtaining means for obtaining a spectral reflectance obtained by irradiating the sample with monochromatic light of an excitation wavelength band, an input means for inputting a spectral radiance of the target light source, and a deriving means for deriving the spectral radiance of the sample on the basis of the obtained spectral reflectance and the input spectral radiance. The obtaining means determines whether the wavelength of the monochromatic light is within a predetermined wavelength band. If the wavelength of the monochromatic light is not within the predetermined wavelength, the obtaining means obtains a spectral reflectance of the wavelength same as the wavelength of the monochromatic light, and if it is within the predetermined wavelength band, the obtaining means obtains the spectral reflectance of the wavelength same as the wavelength of the monochromatic light and the spectral reflectance of the wavelength of the light emission wavelength band based on the phosphorous component of the sample. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a color processing apparatus and a color processing method when a fluorescent component is contained in a sample.

  When an image is output using an image output device such as a printer, color reproduction characteristics (colorimetric values) of the image output device are calculated, and the color of the input image is mapped to a color reproduced by the image output device. Here, the calculation of the color reproduction characteristics of the image output device is generally performed according to a procedure as shown in FIG. 15 by using a general colorimeter shown in FIG. First, a color chart is printed on a predetermined medium by an image output device, and the spectral reflectance R (λ) of the printed color chart is measured by a colorimeter. In the colorimeter shown in FIG. 16, first, light is irradiated onto a sample (color chart) from a colorimetric light source incorporated in the colorimeter. The irradiated light is reflected by the sample, and the light receiver receives the spectral radiance of the reflected light reflected through the spectroscope. Then, the spectral reflectance R (λ) of the sample is calculated by dividing the spectral radiance of the received reflected light by the spectral radiance of the light source. Next, the spectral radiance S (λ) of the light source (observation light source) for observing the output image is measured. Then, from the measured spectral reflectance R (λ), the spectral radiance S (λ) of the observation light source, and the color matching functions x (λ), y (λ), z (λ), the following equation (1) is obtained. Use to calculate CIE tristimulus values XYZ.

  However, when the medium or ink contains a material containing a fluorescent component (fluorescent whitening material, etc.), the spectral reflectance of the image output device measured by the above method may differ from the spectral reflectance under the observation light source. is there. Here, the fluorescence component is a component that reflects light in an excitation wavelength range that is a predetermined wavelength range of irradiation light to a different wavelength range (that is, an emission wavelength range).

  A method for calculating the spectral reflectance when the fluorescent component is included will be described with reference to FIG. When a sample including a fluorescent component is measured using a colorimeter as shown in FIG. 16, the light in the excitation wavelength region reacts with the fluorescent component of the sample and is reflected in the emission wavelength region. For this reason, the colorimeter receives the reflected light in which the amount of fluorescence depending on the spectral radiance in the excitation wavelength range of the colorimetric light source is added. That is, the spectral reflectance also depends on the colorimetric light source. Therefore, as shown in FIG. 18A, when the colorimetric light source and the observation light source are the same, the spectral radiance in the excitation wavelength range of the observation light source and the fluorescence amount correspond to each other, so that a correct XYZ value is calculated. The On the other hand, when the colorimetric light source and the observation light source are different from each other as shown in FIG. Cannot be calculated. That is, there is a problem that if the light source that measures the sample containing the fluorescent component is different from the light source in the actual observation environment, the XYZ value that is the colorimetric value does not correspond to the actual appearance.

  With respect to this problem, Patent Document 1 describes a method of holding measurement data obtained by measuring reflected light of each wavelength with respect to incident light of a monochromatic wavelength in a wavelength range including an excitation wavelength range. . In addition, it is described that measurement data of long-wavelength reflected light with respect to short-wavelength incident light that generally does not cause excitation is not held because the amount of data increases when all of incident light and reflected light are held in association with each other. Has been.

JP 2003-110867 A

  However, the method according to Patent Document 1 also needs to create and manage a large amount of colorimetric values.

  Accordingly, an object of the present invention is to realize accurate color reproduction for a sample containing a fluorescent component under an arbitrary observation environment with a small amount of data.

  The color processing apparatus according to the present invention is a color processing apparatus that calculates a spectral reflectance including a fluorescent component of a sample in a target light source, and obtains a spectral reflectance obtained by irradiating the sample with monochromatic light in an excitation wavelength range. Acquisition means, input means for inputting the spectral radiance of the target light source, and derived means for deriving the spectral radiance of the sample based on the acquired spectral reflectance and the input spectral radiance. The acquisition means determines whether the wavelength of the monochromatic light is within a predetermined wavelength range including an excitation wavelength range, and if the wavelength of the monochromatic light is not within the predetermined wavelength range, the wavelength of the monochromatic light is When the spectral reflectance of the same wavelength is acquired and the wavelength of the monochromatic light is within the predetermined wavelength range, the spectral reflectance of the same wavelength as the wavelength of the monochromatic light and the wavelength of the emission wavelength range due to the fluorescent component of the sample To obtain the spectral reflectance.

  The color processing method according to the present invention is a color processing method for calculating a spectral reflectance including a fluorescent component of a sample in a target light source, and obtains a spectral reflectance obtained by irradiating the sample with monochromatic light in an excitation wavelength range. An acquisition step for inputting the spectral radiance of the target light source, and a derivation step for deriving the spectral radiance of the sample based on the acquired spectral reflectance and the input spectral radiance. The acquisition step determines whether the wavelength of the monochromatic light is within a predetermined wavelength range including an excitation wavelength range, and if the wavelength of the monochromatic light is not within the predetermined wavelength range, the wavelength of the monochromatic light is When the spectral reflectance of the same wavelength is acquired and the wavelength of the monochromatic light is within the predetermined wavelength range, the spectral reflectance of the same wavelength as the wavelength of the monochromatic light and the wavelength of the emission wavelength range due to the fluorescent component of the sample To obtain the spectral reflectance.

  According to the present invention, it is possible to realize accurate color reproduction for a sample containing a fluorescent component under an arbitrary observation environment with a small amount of data.

It is a conceptual diagram explaining the principle of fluorescence. It is a figure which shows the structural example of a color processing apparatus. It is a figure which shows the structural example of a color processing apparatus. It is a flowchart which shows the flow of a process of a color process. It is a flowchart which shows the flow of the process which acquires color chart information. It is a schematic diagram which shows the structural example of the measuring device which measures a color chart. It is a schematic diagram which shows the example of color chart information. It is a flowchart which shows the flow of a spectral radiance calculation process. It is a schematic diagram which shows the detail of a spectral radiance calculation process. It is a figure which shows the structural example of a color processing apparatus. It is a flowchart which shows the flow of a color chart information acquisition process. It is a schematic diagram which shows UI example which sets the wavelength range which receives the influence of a fluorescence component. It is a schematic diagram which shows the example of the reduced color chart information. It is a figure which shows the structural example of a color processing apparatus. It is a schematic diagram which shows the conventional colorimetric value calculation procedure. It is a schematic diagram which shows the structure of the conventional colorimeter. It is a schematic diagram explaining the conventional method of colorimetric value calculation of a color chart. It is a schematic diagram explaining the conventional method of colorimetric value calculation of the color chart which receives the influence of a fluorescence component.

Example 1
First, the fluorescent component will be described with reference to FIG. Here, the fluorescent component is a component that emits light in an excitation wavelength range, which is a predetermined wavelength range of illumination light, in a different wavelength range (that is, an emission wavelength range). FIG. 1 is a schematic diagram showing measured values obtained by measuring reflected light from a color chart when a color chart containing a fluorescent component is irradiated with monochromatic light.

  FIG. 1A shows the intensity of light reflected from the color chart when the color chart (sample) is irradiated with monochromatic light of 350 nm. Here, reference numeral 101 in the figure denotes 350 nm reflected light with respect to the irradiated 350 nm monochromatic light, and reference numeral 102 in the figure denotes fluorescence emitted by a fluorescent component excited by the irradiated 350 nm monochromatic light at 440 nm.

  On the other hand, FIG. 1B shows the intensity of light reflected from the color chart when the color chart is irradiated with monochromatic light of 440 nm. Here, reference numeral 103 in the drawing denotes reflected light of 440 nm with respect to the irradiated monochromatic light of 440 nm.

  When the color chart contains a fluorescent component, when the light having the excitation wavelength is irradiated as shown in FIG. 1A, light is emitted at a wavelength different from the wavelength of the irradiated light apart from the reflected light having the wavelength of the irradiated light. Observed. On the other hand, when light other than the excitation wavelength is irradiated, reflected light having the wavelength of the irradiated light is observed. Therefore, 440 nm light observed from the color chart under the light source including both wavelength components of 350 nm and 440 nm is the sum of the light emission 102 and the reflected light 103. Of course, since a general light source has many wavelength components, the sum of reflected light and light emission at 440 nm for each wavelength becomes 440 nm light observed from the color chart under the light source.

  Therefore, in order to obtain a colorimetric value of a color chart including a fluorescent component under an arbitrary observation environment, the correspondence between the light irradiated to the color chart and the reflected light and the light source information of the observation environment (target light source) are used. It is necessary to calculate a colorimetric value based on this. Hereinafter, color processing in the present embodiment will be described with reference to the drawings.

(Color processing device)
A configuration example of the color processing apparatus according to this embodiment will be described with reference to FIG. 2, the color processing apparatus includes a CPU 201, a main memory 202, an HDD 203, a general-purpose interface 204, a monitor 205, and a main bus 206. The general-purpose interface 204 connects the measuring device 207, the image output device 208, and the like to the main bus 206.

  Hereinafter, various processes realized by the CPU 201 operating various software (computer programs) stored in the HDD 203 will be described.

  First, the CPU 201 activates a color processing application stored in the HDD 203, expands it in the main memory 202, and displays a user interface on the monitor 205. Subsequently, various data stored in the HDD 203 and measurement values input from the measuring device 207 connected to the general-purpose interface 204 are transferred to the main memory 202 via the main bus 206 based on a command from the CPU 201. The Note that the measuring device 207 includes various measuring devices, and measures, for example, an image output from the image output device 208 and a light source based on a command from the CPU 201. Further, according to the processing in the color processing application, the data stored in the main memory 202 performs various calculations based on commands from the CPU 201, and displays the calculation results on the monitor 205 via the main bus 206, Or store.

  In the above configuration, color processing performed by inputting spectral characteristics of a color chart including a fluorescent component output from an image output device by a color processing application based on a command from the CPU 201 and spectral characteristics of a light source in an observation environment will be described.

  FIG. 3 is a diagram illustrating the configuration of the color processing apparatus. As described above, in this embodiment, the configuration described in FIG. 3 is realized as color processing application software. In FIG. 3, an image output apparatus 301 is a printer that outputs a color chart. The color chart measuring device 302 measures the color chart output by the image output device 301. The light source measuring device 303 measures the spectral distribution of the light source in the observation environment. The color processing unit 304 executes color processing and corresponds to the color processing apparatus of FIG. 2 and a color processing application that operates on the color processing apparatus. The color chart information input unit 305 inputs spectral characteristics of the color chart, and inputs color chart information from the color chart measuring device 302 connected to the general-purpose interface 204 to the color processing section 304. The light source information input unit 306 inputs spectral characteristics of the light source in the observation environment, and inputs light source information from the light source measuring device 303 connected to the general-purpose interface 204 to the color processing unit 304. The spectral radiance calculation unit 307 calculates the spectral radiance according to the instruction from the CPU 201 based on the color chart information obtained by the color chart information input unit 305 and the light source information obtained by the light source information input unit 306. The colorimetric value calculation unit 308 calculates a colorimetric value according to an instruction from the CPU 201 based on the spectral radiance calculated by the spectral radiance calculation unit 307.

  Hereinafter, details of each process in the color process of FIG. 3 will be described with reference to the flowchart of FIG.

In step S401, the color chart is output from the image output device 301. Hereinafter, in this embodiment, the image output device 301 is a printer that receives color signal values of 256 tones for each of RGB, and outputs a color chart of 729 (= 9 ³ ) colors in total for 9 steps for each of RGB. explain. Here, the number of color charts may be a number sufficient to obtain the color reproduction characteristics of the image output apparatus 301. Therefore, the number of color charts to be output is not limited to this, and the number of color charts may be changed according to the color reproduction accuracy desired by the user.

In step S402, the color chart output in step S401 is measured by the color chart measuring device 302, and the color chart information is input from the color chart information input unit 305 to the color processing unit 304. Details of the color chart information input process will be described later. Here, the input color chart information is a set of the wavelength of the monochromatic light irradiated on the color chart and the spectral reflectance from the color chart, and the wavelength of the monochromatic light varies depending on the calculation accuracy of the desired colorimetric value. Get multiple pairs. Note that at least one of the color chart information to be input is a light source including the excitation wavelength region of the fluorescent substance included in the color chart, so that the influence of fluorescence can be input as the color chart information. Hereinafter, in this embodiment, the spectral reflectance input by the color chart information input unit will be described as R _x (λ) (380 nm ≦ λ ≦ 780 nm). Note that _x in the spectral reflectance R _x (λ) indicates the wavelength of monochromatic light irradiated on the color chart.

  In step S403, the light source in the observation environment is measured by the light source measuring device 303, and the light source information is input from the light source information input unit 306 to the color processing unit 304. The light source information input here is the spectral radiance of the light source, and more preferably a light source including the excitation wavelength range of the fluorescent material included in the color chart. In the case of a light source that does not include an excitation wavelength region, light source information may be input with the spectral radiance in the excitation wavelength region set to zero. Hereinafter, in this embodiment, the spectral radiance acquired by the light source information input unit 306 will be described as S (λ) (300 nm ≦ λ ≦ 780 nm).

  In step S404, based on the color chart information obtained by the color chart information input section 305 and the light source information obtained by the light source information input section 306, the spectral radiance calculation section 307 uses the spectral radiance under the observation light of the color chart. It is derived by calculating. Details of the spectral radiance calculation processing will be described later. Here, the derived spectral radiance includes the visible wavelength region (380 nm ≦ λ ≦ 780 nm). Hereinafter, in this embodiment, the derived spectral radiance will be described as T (λ) (380 nm ≦ λ ≦ 780 nm).

  In step S405, the colorimetric value calculation unit 308 calculates the colorimetric value of the color chart based on the spectral radiance T (λ) derived in step S404. Here, a CIEXYZ value calculation method will be described as an example of the calorimetric value to be calculated. Color matching function

Then, the CIEXYZ values are respectively expressed by the following equations.

  Here, k is a constant. For example, when normalization is performed based on the spectral radiance S (λ) of the light source, it may be obtained by the following equation.

  The color matching function used for colorimetric value calculation is input by a desired method. For example, the color matching function stored in advance by the color processing application may be read. Alternatively, the data may be stored in advance in the HDD 203 in the color processing apparatus and read out, or may be input from an external storage device connected to the general-purpose interface 204.

(How to use colorimetric values in CMS)
The calculated colorimetric value can be used in a color management system (CMS). The CMS is a system that performs color conversion so that an equivalent color reproduction can be obtained between different devices by correcting a difference in a color reproduction range that is different for each device. In CMS, color matching between different devices is realized while mutually converting a device-dependent color space (RGB, CMYK, etc.) and a device-independent color space (CIEXYZ, CIELAB, etc.). For mutual conversion between the device-dependent color space and the device-independent color space, a profile (ICC profile or the like) storing the color reproduction characteristics of the device is used. The profile stores the color reproduction characteristics of the device as a conversion formula or conversion table (LUT), and the color space can be mutually converted by referring to the profile.

Therefore, by calculating the XYZ values of each color chart of 729 (= 9 ³ ) colors in total for each of 9 steps of RGB based on the flowchart of FIG. 4 and creating a profile describing the correspondence between RGB and XYZ as an LUT. It can be used for general CMS.

(Color chart information input process)
Hereinafter, details of color chart information input in step S402 and examples of color chart information to be input will be described with reference to FIGS.

  FIG. 5 is a flowchart for explaining the flow of processing for measuring a color chart using the color chart measuring device 302 and inputting the color chart information to the color chart information input unit 305.

In step S501, the start wavelength λ _S , end wavelength λ _e , and wavelength interval Δλ of monochromatic light emitted when measuring the color chart are determined. The monochromatic light applied to the color chart includes the excitation wavelength and the visible wavelength component of the fluorescent component included in the color chart, and the wavelength interval is determined according to the required color reproduction accuracy. If the wavelength interval is narrowed, the color reproduction accuracy is improved, but the measurement time and the amount of information obtained from the measurement are increased. On the contrary, if the wavelength interval is widened, the color reproduction accuracy is lowered, but the measurement time and the amount of information obtained from the measurement are reduced. Hereinafter, in this embodiment, description will be made assuming that the start wavelength is 300 nm, the end wavelength is 780 nm, and the wavelength interval is 10 nm.

In step S502, the measurement wavelength λ _i is determined. The first measurement wavelength is λ ₀ = λ _S , and Δλ is added for each subsequent measurement to determine the measurement wavelength. Therefore, in this embodiment, the measurement is performed by sequentially irradiating the color chart with 49 measurement wavelengths of λ _i = 300, 310, 320,..., 780 (i = 0 to 48).

In step S503, the spectral radiance is measured by irradiating the color chart with monochromatic light P (λ _i ) of λ _i nm.

Here, an example of a measuring instrument for measuring the spectral radiance of the color chart will be described with reference to FIG. In FIG. 6, a light source 601 is a light source P (λ) for irradiating a color chart. The spectroscope 602 splits the light source 501 and outputs monochromatic light P (λ _i ) having a wavelength λ _i nm. The color chart 603 is a color chart to be measured. The spectroscope 604 receives the spectral radiance Q (λ) from the color chart 603 and separates it into each wavelength in the visible wavelength region. In the following description, the visible range is described as a wavelength range from 380 nm to 780 nm. The light receiver 605 measures the radiance Q (λ _j ) of each wavelength separated by the spectroscope 604.

  By using the color chart measuring device having such a configuration, it is possible to acquire desired color chart information. The configuration of the measuring device is not limited to this as long as it can irradiate the color chart with light of a plurality of single wavelengths and can measure reflected light and light emission from the color chart. For example, the light source 601 and the spectroscope Instead of 602, a color chart may be irradiated by switching a monochromatic light source such as a laser beam.

In step S504, the spectral reflectance is calculated from the monochromatic light P (λ _i ) irradiated with the color chart and the measured spectral radiance Q (λ). Here, the spectral reflectance R (λ) of the color chart is as follows.

In step S <b> 505, color chart information including a set of monochromatic light P (λ _i ) and spectral reflectance R _λi (λ) is acquired. An example of the acquired color chart information will be described with reference to FIG.

In FIG. 7, each row corresponds to the wavelength λ _i of the monochromatic light irradiated to the color chart, which is the input wavelength. Each column is an output wavelength and is a spectral reflectance R (λ) from the color chart. Accordingly, the color chart information acquired in the present embodiment is represented by a matrix of 49 rows and 41 columns as shown in FIG.

In step S506, the measurement wavelength λ _i is compared with the end wavelength λ _e to determine whether or not to continue the measurement. In the case of this example, when the measurement wavelength is 780 nm, the measurement is terminated, and when it is not 780 nm, the process proceeds to S402 and the measurement is continued.

  The color chart information acquired by the above processing is input to the color processing unit 304.

  In the present embodiment, the example in which the color chart information is obtained from the measuring instrument and input from the outside of the color processing apparatus has been described. However, the color chart information input means is not limited to this. For example, in the color processing apparatus of FIG. 1, color chart information stored in advance in the HDD 203 may be read and input.

(Spectral radiance calculation processing)
Details of the spectral radiance calculation processing in step S404 will be described below with reference to FIGS.

  FIG. 8 is a flowchart for explaining the flow of processing for calculating the spectral radiance based on the color chart information and the light source information.

In step S801, the color chart information acquired in step S402 and the light source information acquired in step S403 are acquired. The color chart information acquired here is a set R _X (λ) (300 nm ≦ x ≦ 780 nm, 380 nm ≦ λ ≦ 780 nm) of monochromatic light and spectral reflectance shown in FIG. The light source information acquired here is the spectral radiance S (λ) (300 nm ≦ λ ≦ 780 nm) of the light source including the excitation wavelength range of the fluorescent component.

In step S802, a start wavelength λ _S , an end wavelength λ _e , and a wavelength interval Δλ for calculating the spectral radiance are determined. The wavelength for calculating the spectral radiance includes the excitation wavelength and the visible wavelength component of the fluorescent component included in the color chart, and the wavelength interval is determined according to the required color reproduction accuracy. If the wavelength interval is narrowed, the color reproduction accuracy is improved, but the calculation amount and the information amount are increased. On the other hand, if the wavelength interval is widened, the amount of calculation and the amount of information that reduce the color reproduction accuracy decrease. In the following description, the start wavelength is 300 nm, the end wavelength is 780 nm, and the wavelength interval is 10 nm.

In step S803, the calculated wavelength λ _i is determined. The first calculated wavelength is λ ₀ = λ _S , and Δλ is added for each subsequent measurement to determine the calculated wavelength. Thus, lambda _i = 300, 310, 320 in the case of this embodiment, ..., sequentially calculates the spectral radiance of the 49 kinds of 780 (i = 0~48).

In step S804, the radiance S (λ _i ) of λ _i nm is acquired from the light source information acquired in step S801.

In step S805, spectral reflectance R _λi (λ) for monochromatic light of λ _i nm is acquired from the color chart information acquired in step S801.

In step S806, the spectral radiance is calculated from the radiance S (λ _i ) acquired in step S804 and the spectral reflectance R _λi (λ) acquired in step S805. The spectral radiance T _λi (λ) is expressed by the following equation.

In step S807, the calculated wavelength λ _i is compared with the end wavelength λ _e to determine whether or not to continue calculating the spectral radiance. In this embodiment, if the calculated wavelength is 780 nm, the process proceeds to step S808. If the calculated wavelength is other than 780 nm, the process proceeds to step S803 and the calculation of the spectral radiance is continued.

In step S808, the spectral radiance T _λi (λ) calculated in steps S803 to S805 is integrated for each wavelength, and the spectral radiance T (λ) under the light source acquired in step S801 is calculated.

Details of the process for calculating the spectral radiance T (λ) under the light source acquired in step S801 from the spectral radiance T _λi (λ) calculated in steps S803 to S806 will be described with reference to FIG. . In FIG.
The spectral radiance 901 is the light source information acquired in step S801, and is the spectral radiance S (λ) (300 ≦ λ ≦ 780) of the light source including the excitation wavelength region of the color chart.

  The radiance 902 and the radiance 903 are radiances of monochromatic light obtained from the light source information acquired in S801, and correspond to the radiance acquired in step S804. Here, the radiance 803 is the radiance S (350) of monochromatic light of 350 nm, and the radiance 804 is the radiance S (440) of monochromatic light of 440 nm. For convenience, only the radiance of two monochromatic lights is shown, but the radiance of each monochromatic light from 300 nm to 780 nm is obtained from the light source information acquired in step S801. Note that the sum of these monochromatic lights matches the spectral radiance S (λ) of the light source indicated by reference numeral 901 in the figure.

The spectral reflectance 904 and the spectral reflectance 905 are spectral reflectances obtained from the color chart information acquired in step S801, and correspond to the spectral reflectances acquired in step S805. Here, 904 is the spectral reflectance R ₃₅₀ (λ) for monochromatic light of ₃₅₀ nm, and 805 is the spectral reflectance R ₄₄₀ (λ) for monochromatic light of 440 nm.

The radiance 906 and the spectral radiance 907 are the spectral radiance calculated from the radiance acquired in step S804 and the spectral reflectance acquired in step S805, and correspond to the spectral reflection luminance calculated in step S806. Here, the spectral radiance 806 is the spectral radiance T ₃₅₀ (λ) of the color chart for 350 nm monochromatic light, and the spectral radiance 807 is the spectral radiance T ₄₄₀ (λ) for monochromatic light of 440 nm.

  The sum 908 is the sum of the spectral radiances of the monochromatic lights of the observation light source calculated based on the color chart information and the intersection information acquired in step S801, and corresponds to the spectral radiance calculated in step S808. Accordingly, the spectral radiance T (λ) of the color chart with respect to the light source is expressed by the following equation.

  Through the above processing, the spectral radiance is calculated in step S304.

  According to the above-described embodiment, by using a set of monochromatic light and spectral reflectance irradiated to the color chart, accurate color reproduction can be performed in an arbitrary observation environment for a printed matter including a fluorescent component.

(Example 2)
In the first embodiment, FIG. 7 is shown as an example of color chart information input from the color chart information input unit 305. As shown in FIG. 7, when all the sets of monochromatic light and spectral reflectance irradiated to the color chart are acquired, accurate color reproduction is possible, but the amount of information becomes enormous and handling of the color chart information becomes difficult. In the case of Example 1, monochromatic light of 300 nm to 780 nm is irradiated per color chart, and the reflectance of light of 380 nm to 780 nm is obtained at intervals of 10 nm. Accordingly, 41 spectral reflectances are required for each of 49 wavelengths of monochromatic light to be irradiated. As a result, the input color chart information is 2000 or more.

  Therefore, an example will be described in which color chart information excluding spectral reflectance that has little influence on colorimetric value calculation is obtained by acquiring information on fluorescent components included in the color chart in advance. Hereinafter, a process of acquiring color chart information with a reduced information amount will be described with reference to FIGS. 10 to 13.

  FIG. 10 is a block diagram showing the configuration of the color processing apparatus in this embodiment. Note that the description of the same configuration as that of FIG. An instruction unit 1009 instructs color chart information to be input to the color chart information input unit 1005 from the UI of the color processing application displayed on the monitor 205.

  FIG. 11 is a flowchart of color chart information input processing in which the amount of information is reduced. Description of the same processing as in FIG. 5 in the first embodiment is omitted, and details of processing corresponding to S505 will be described.

  In step S1101 of FIG. 11, the excitation wavelength range and the emission wavelength range of the fluorescent component included in the color chart are input from the instruction unit 1009.

  Here, the instruction of the wavelength range affected by the fluorescent component from the instruction unit 1009 will be described with reference to FIG. FIG. 12A shows an example of a UI screen for instructing a wavelength range affected by a fluorescent component from a color processing application. The minimum wavelength and the maximum wavelength in the wavelength range affected by the fluorescent component are input from the user's instruction. If the fluorescent whitening agent is known for each sheet on which the color chart is printed, the excitation wavelength region and the emission wavelength recorded in advance in the HDD 203 or the like can be selected by selecting the sheet type as shown in FIG. You may input by reading the area. Note that the input method is not limited to the above method. For example, when the fluorescent component of the ink is known, the fluorescent component such as the method of selecting the type of ink, as in the case of the above-described paper, is used. What is necessary is just to be able to identify the excitation wavelength region and the emission wavelength region.

In step S1102, the minimum value λ _min and the maximum value λ _max of the excitation wavelength range of the fluorescent component included in the color chart are set based on the wavelength range affected by the fluorescent component acquired in step S1101. Here, λ _min = 300 nm and λ _max = 400 nm will be described as an example.

  In step S1103, the wavelength λ of the monochromatic light irradiated on the color chart is acquired.

  In step S1104, it is determined whether the wavelength λ of the monochromatic light irradiated on the color chart is included in the excitation wavelength range. As a result of the determination, if the wavelength λ is included in the excitation wavelength region, the process proceeds to step S1105, and if not, the process proceeds to step S1106.

  In step S1105, a set of the wavelength of the monochromatic light irradiated on the color chart and the spectral reflectance in the emission wavelength region is acquired. Here, an example in which the emission wavelength region is 400 nm to 500 nm will be described.

  In step S1106, a set of the wavelength of the monochromatic light irradiated on the color chart and the spectral reflectance of the same wavelength is acquired.

FIG. 13 is a schematic diagram illustrating an example of color chart information acquired by the color chart information acquisition process of FIG. In FIG. 13, each row is an input wavelength corresponding to the wavelength λ _i of the monochromatic light irradiated on the color chart, and each column is an output wavelength. The spectral reflectance R (λ) from the color chart is stored in each row and column. As shown in FIG. 13, when the input wavelength is in the excitation wavelength range, the spectral reflectance in the emission wavelength range is acquired. When the input wavelength is the excitation wavelength region and the emission wavelength region, both the spectral reflectance having the same wavelength as the input wavelength and the spectral reflectance having a wavelength within the emission wavelength region are acquired. Furthermore, when the input wavelength range is other than that, only the spectral reflectance of the same wavelength as the input wavelength is acquired.

  Therefore, the color chart information acquired in the present embodiment is about 160, and can be reduced to about one tenth of that in the first embodiment. Therefore, the color chart information can be efficiently handled with a small amount of data.

  The color chart information acquisition process is not limited to the present embodiment. For example, a threshold T (for example, T = 400 nm) for the spectral reflectance is set according to an instruction from the user according to the desired color reproduction accuracy, and a spectral reflectance smaller than the threshold T is not acquired as color chart information. Processing may be performed.

(Example 3)
In the first and second embodiments, an example of color processing for calculating a colorimetric value based on information input from a color chart measuring device and an observation light source measuring device connected to the outside of the color processing device has been described. There is no need to get information from. For example, the measuring device may be configured to include a color processing unit. FIG. 14 shows the configuration of the color processing apparatus in this embodiment.

  In FIG. 14, a measurement unit 1401 measures the color chart output from the image output apparatus and the light source information of the observation environment. The measurement of the color chart is the same as that of the color chart measuring device 302 and the measurement of the light source is the same as that of the light source measuring device 303. The computing unit 1402 calculates spectral radiance and colorimetric values by using the color chart information and light source information measured by the measuring unit as inputs. The calculation of the spectral radiance is the same as that of the spectral radiance calculation unit 307, and the calculation of the colorimetric value is the same as that of the colorimetric value calculation unit 308. The storage unit 1403 stores a measurement value obtained by the measurement unit 1401, a calculation result obtained by the calculation unit 1402, and the like.

  In addition, as an example of the configuration of the color processing apparatus according to the present embodiment, the measuring device includes the calculation unit and the storage unit, but the configuration example is not limited thereto. Any configuration that can input color chart information and light source information and calculate the spectral radiance may be used. For example, an image output device that outputs a color chart may include a measurement unit and a calculation unit.

  With the color processing apparatus having the above-described configuration, it is possible to realize accurate color reproduction with a small amount of data for an arbitrary viewing environment for a printed matter including a fluorescent component.

(Other examples)
The present invention is also realized by executing the following processing. That is, computer-readable software (computer program) that implements the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media. This is a process in which a computer (or CPU, MPU, etc.) of the system or apparatus reads and executes the program.

Claims (9)

A color processing device that calculates a spectral reflectance including a fluorescent component of a sample in a target light source,
An acquisition means for acquiring a spectral reflectance obtained by irradiating a sample with monochromatic light in an excitation wavelength range;
Input means for inputting the spectral radiance of the target light source;
Derivation means for deriving the spectral radiance of the sample based on the acquired spectral reflectance and the input spectral radiance;
The acquisition unit determines whether the wavelength of the monochromatic light is within a predetermined wavelength range including an excitation wavelength range. If the wavelength of the monochromatic light is not within the predetermined wavelength range, the same wavelength as the wavelength of the monochromatic light is determined. When the wavelength of the monochromatic light is within the predetermined wavelength range, the spectral reflectance of the same wavelength as the wavelength of the monochromatic light and the spectral wavelength of the emission wavelength range due to the fluorescent component of the sample are obtained. A color processing apparatus that acquires reflectance.   The color processing apparatus according to claim 1, wherein the predetermined wavelength range is a wavelength range set in accordance with a user instruction.   The color processing apparatus according to claim 1, wherein the predetermined wavelength range is a wavelength range smaller than 380 nm.   The color processing apparatus according to claim 1, wherein the wavelength of the monochromatic light is a wavelength in a range of 380 nm to 730 nm.   5. The color processing apparatus according to claim 1, wherein the spectral radiance input by the input unit includes spectral radiance in an excitation wavelength region of a fluorescent component included in the sample. The derivation means includes
Radiance acquisition means for acquiring radiance of monochromatic light based on the spectral radiance input by the input means;
First calculation means for calculating a spectral radiance based on the radiance acquired by the radiance acquisition means and the spectral reflectance acquired by the acquisition means;
Calculating a plurality of monochromatic lights having different wavelengths from the wavelength of the monochromatic light using the first calculating means, and a second calculating means for calculating a sum of the calculated spectral radiances. The color processing apparatus according to claim 1, wherein the color processing apparatus is a color processing apparatus. A color processing method for calculating a spectral reflectance including a fluorescent component of a sample in a target light source,
An acquisition step of acquiring a spectral reflectance obtained by irradiating a sample with monochromatic light in an excitation wavelength range;
An input process for inputting the spectral radiance of the target light source;
A derivation step of deriving a spectral radiance of the sample based on the acquired spectral reflectance and the input spectral radiance;
The acquisition step determines whether the wavelength of the monochromatic light is within a predetermined wavelength range including an excitation wavelength range. If the wavelength of the monochromatic light is not within the predetermined wavelength range, the same wavelength as the wavelength of the monochromatic light is determined. When the wavelength of the monochromatic light is within the predetermined wavelength range, the spectral reflectance of the same wavelength as the wavelength of the monochromatic light and the spectral wavelength of the emission wavelength range due to the fluorescent component of the sample are obtained. A color processing method characterized by acquiring reflectance.   A computer program for causing a computer to function as each unit of the color processing apparatus according to any one of claims 1 to 6 when executed on the computer.   A computer-readable storage medium storing the program according to claim 8.

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