JP5677123B2 - Color processing apparatus and color processing method - Google Patents

Description

  The present invention relates to color processing for obtaining color reproduction characteristics of a sample containing a fluorescent material.

  In the color matching process for matching the reproduction colors of the image input device, the image display device, and the image output device, the reproduction colors of each device are associated in consideration of the color reproduction characteristics of each device to be matched.

  FIG. 15 shows an example of a procedure for acquiring the color reproduction characteristics of the image output device. First, a color chart based on the color chart data 21 is printed on a predetermined medium by an image output device to form a sample (S22), and a spectral radiance factor of the sample is acquired (S23). The spectral radiance factor of a sample is generally calculated from measured values (spectral radiance) obtained by the measurement method shown in FIG. According to FIG. 16, the sample 11 is irradiated with light from the light source (measurement light source) 12 prepared for measurement, and the light reflected by the sample 11 is received by the light receiver 14 through the spectroscope 13. The spectral radiance of is measured. By dividing the spectral radiance of the reflected light by the spectral radiance of the measurement light source, the spectral radiance factor β (λ) of the sample is calculated. Therefore, the spectral radiance factor β (λ) is synonymous with the spectral reflectance. Next, the spectral radiance S (λ) of the light source (observation light source) 24 in the environment for observing the sample is measured (S25). The spectral radiance factor β (λ), the spectral radiance S (λ) of the observation light source, and the color matching functions x to (λ), y to (λ), z to (λ) (x to The CIE tristimulus value XYZ27 is calculated using the following equation (1) (S26).

  In other words, if a sample 11 is formed by printing color charts of a large number of colors on a medium using an image output device, and the colorimetric values (for example, tristimulus values XYZ27) of each color chart are obtained, the image is printed when the color chart is printed. The relationship between the signal value (for example, RGB value) 21 input to the output device and the colorimetric value is obtained. This correspondence represents the color reproduction characteristics of the image output device.

  However, when a fluorescent material (fluorescent substance such as fluorescent whitening material) is used for media or ink, the spectral radiance factor of the sample calculated by the above method is different from the spectral radiance factor under the observation light source. There is a case. The fluorescent substance emits light in a wavelength range (fluorescence wavelength range) different from the excitation wavelength range included in the irradiation light. In general, the fluorescence wavelength is longer than the excitation wavelength.

  With reference to FIG. 17, the spectral radiance factor of a sample containing a fluorescent material having an excitation wavelength in the ultraviolet region (hereinafter referred to as a fluorescent sample) will be described. FIG. 17 (a) shows the spectral radiance of the measurement light source, and the shaded area shows the ultraviolet region (excitation wavelength region). FIG. 17 (b) shows the spectral radiance from the fluorescent sample when the measurement light source shown in FIG. 17 (a) is irradiated, and the ultraviolet region in which the fluorescent substance is included in the irradiation light (the hatched line in FIG. 17 (a)). In the fluorescence wavelength region (shaded area in FIG. 17B) is emitted. FIG. 17 (c) shows the spectral radiance factor obtained by dividing the spectral radiance from the fluorescent sample shown in FIG. 17 (b) by the spectral radiance of the measurement light source shown in FIG. The increase in the spectral radiance factor due to is shown. That is, the spectral radiance factor of the fluorescent sample depends on the fluorescence emission amount (fluorescence amount), and the fluorescence amount depends on the spectral radiance in the excitation wavelength region of the measurement light source.

  Here, when the measurement light source and the observation light source are the same, the amount of fluorescence emitted by the fluorescent sample in both light sources is also equal. Therefore, the XYZ value calculated by the spectral radiance factor under the measurement light source (that is, the spectral radiance factor under the observation light source) with the same amount of fluorescence as that emitted by the fluorescent sample under the observation light source becomes the observation light source. Corresponds to the actual appearance below.

  However, when the measurement light source and the observation light source are different, the amount of fluorescence emitted by the fluorescent sample in both light sources is also different. Therefore, the XYZ values calculated based on the spectral radiance factor under the measurement light source in which a fluorescence amount different from the fluorescence amount emitted from the fluorescent sample under the observation light source does not correspond to the actual appearance under the observation light source. Therefore, in order to calculate the XYZ values corresponding to the actual appearance under the observation light source, the measurement is performed under the observation light source, and the spectral radiance factor that takes into account the amount of fluorescence emitted by the fluorescent sample under the observation light source is calculated. Need to get.

  Hereinafter, a method for obtaining the spectral radiance factor under the measurement light source and the observation light source will be described. First, when measuring the spectral radiance factor under a measurement light source, specifically, a colorimeter including a light source 12, a spectroscope 13, and a light receiver 14 is used to realize a measurement system as shown in FIG. . When measuring the spectral radiance factor of the sample 11 with an external colorimeter, the fluorescent sample 11 and the measuring device are brought into contact with each other. Thereby, the optical path d1 from the light source 12 to the sample 11 and the optical path d2 from the sample 11 to the light receiver 14 are shortened, and a decrease in the amount of light incident on the light receiver 14 is suppressed. As the light source 12, a light source that can obtain a sufficient amount of light in the visible wavelength region is used. By securing the amount of light received by the light receiver 14 as described above, measurement can be performed in a short time.

  Next, the measurement of the spectral radiance factor under the observation light source will be described. Here, the observation light source refers to illumination light in an environment where the user observes the printed matter. Therefore, since there is a distance, that is, a space between the sample 11 and the observation light source, it is considered that when the measurement is performed under the observation light source, the amount of light incident on the light receiver 14 is lower than in the case of the measurement light source. It is done. Furthermore, when irradiating the sample 11 with the observation light source, the measurement device including the light receiver 14 cannot be brought into contact with the sample 11. Therefore, compared with the case where the measurement light source is used, the sample 11 to the light receiver 14 can be compared. The optical path d2 up to is long. Further, the optical path d1 from the light source 12 to the sample 11 is determined according to the observation conditions.

  As described above, when the spectral radiance factor is measured under the observation light source, the amount of light received by the light receiver 14 cannot be secured sufficiently, and there is a problem that the measurement time becomes long.

  To solve this problem, a method has been proposed for estimating the spectral radiance factor under the observation light source by measuring the spectral radiance factor under the measurement light source without performing the measurement under the observation light source. (For example, Patent Document 1). According to this method, a fluorescence characteristic called a bispectral radiance factor of a standard fluorescent sample is measured in advance, and the total spectral radiance factor under the observation light source is determined using this fluorescence property and the total spectral radiance factor under the measurement light source. Is estimated.

JP 2009-236486 A

  As described above, when measuring the spectral radiance factor under the observation light source, the amount of light received by the light receiver 14 may not be sufficiently secured, and in such a case, the measurement time becomes long. There is.

  On the other hand, when the spectral radiance factor under the observation light source is estimated by the method described in Patent Document 1, there is no need to perform the measurement under the observation light source, but the two spectral radiance factor of the standard fluorescent sample is referred to. It is necessary to measure in advance the fluorescence characteristics. Furthermore, the fluorescence characteristics of the sample to be measured and the standard fluorescence sample must be approximated. Therefore, a new problem arises regarding the method for obtaining the fluorescence characteristics of the standard fluorescent sample and the method for selecting the standard fluorescent sample.

  In view of the above points, an object of the present invention is to easily and quickly acquire the spectral radiance factor of a target color under an observation light source.

  In order to achieve the above object, the color processing apparatus of the present invention comprises the following arrangement.

That is, the spectral radiance factor based on the reflected light and fluorescence from the reference color sample, measured under the measurement light source for the reference color sample printed with a predetermined reference color, is acquired as the reference luminance rate under the measurement light source. Means for obtaining a reference luminance rate under a measurement light source, and a reference reflectance for obtaining, as a reference reflectance, a spectral radiance factor based on only reflected light from the reference color sample measured under the measurement light source for the reference color sample And a reference luminance ratio under the observation light source for obtaining a spectral radiance factor based on the reflected light and fluorescence from the reference color sample measured under the observation light source as the reference luminance ratio under the observation light source. And obtaining fluorescence emission from the reference color sample under the measurement light source and under the observation light source from the measurement light source reference luminance rate, the observation light source reference luminance rate, and the reference reflectance. A fluorescence correction coefficient calculating means for calculating a fluorescence correction coefficient indicating a ratio of the amount, and a reflection from the target color sample measured under the measurement light source for a target color sample printed with a target color different from the reference color Means for obtaining a luminance ratio under a measurement light source for obtaining a spectral radiance ratio based on light and fluorescence as a luminance ratio under the measurement light source, and reflected light from the target color sample measured under the measurement light source for the target color sample The target acquisition color under the observation light source based on the reflectance acquisition means for acquiring the spectral radiance factor based on the reflectance as the reflectance, the difference between the luminance factor under the measurement light source and the reflectance, and the fluorescence correction coefficient have a calculation means of observation under a light source luminance factor for calculating the spectral radiance factor of the sample as an observation light source under luminance factor, acquiring means acquiring means and the reflectance of the reference reflectance, the emitted light of the measurement light source From The light was removed outer zone was determined by irradiating the reference color samples and the target color sample, and obtains the reference reflectance and the reflectance.

  According to the present invention, the spectral radiance factor of the target color under the observation light source can be acquired easily and in a short time.

FIG. 2 is a block diagram showing a hardware configuration of a color processing apparatus according to the first embodiment. FIG. 2 is a block diagram showing a functional configuration of a color processing apparatus according to the first embodiment. The figure which shows the measuring method of a reflection spectral radiance factor, A flowchart showing a process for acquiring a spectral radiance factor under an observation light source of a target color, The figure which shows the example of a user interface in 1st Embodiment. The figure which shows the data structure of a spectral radiance factor, A flowchart showing fluorescence correction coefficient calculation processing; The figure which shows the concept of the increase amount of the spectral radiance factor by fluorescence, A flowchart showing a calculation process of a spectral radiance factor, The figure which shows the concept of the calculation method of the spectral radiance factor under the observation light source of object color, A block diagram showing a hardware configuration of a color processing device in a second embodiment; FIG. 5 is a block diagram showing a functional configuration of a color processing apparatus according to the second embodiment. The figure which shows the example of a user interface in 2nd Embodiment. The figure which shows the functional block structure of the color correction profile creation apparatus in 3rd Embodiment. The figure explaining the example of a procedure which acquires the color reproduction characteristic of an image output device, The figure which shows the general measuring method of the spectral radiance factor of a sample, It is a figure explaining the spectral reflectance of the sample containing a fluorescent material.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. The following embodiments do not limit the present invention according to the claims, and all the combinations of features described in the present embodiments are not necessarily essential to the solution means of the present invention. Absent.

<First Embodiment>
As described above, when the medium contains a fluorescent material, it is necessary to use the spectral radiance factor of the sample in order to accurately obtain the colorimetric value of the sample under an arbitrary observation environment. However, when measuring the spectral radiance factor under the observation light source, if the amount of light received by the light receiver cannot be secured sufficiently, the measurement time becomes long. Therefore, in the present embodiment, the spectral radiance factor under an observation light source and a measurement light source is measured for a certain color, and a fluorescence correction coefficient is calculated. Then, for a sample of any color, the spectral radiance factor under the observation light source is calculated in a short time by multiplying the spectral radiance factor under the measurement light source by the fluorescence correction coefficient. Hereinafter, a color chart formed by printing a color material on a medium is referred to as a sample.

Apparatus Configuration FIG. 1 is a block diagram showing a hardware configuration of a color processing apparatus according to this embodiment. In the figure, 101 is a CPU, 102 is a main memory, 103 is a HDD, 104 is a general-purpose interface, 105 is a monitor, 106 is a main bus, 107 is an instruction input unit such as a keyboard and a mouse, and 108 is an external storage device. The general-purpose interface 104 connects the instruction input unit 107, the external storage device 108, and the like to the main bus 106. Hereinafter, various processes realized by the CPU 101 operating various software programs including the general-purpose OS stored in the HDD 103 will be described.

  First, the CPU 101 activates an information processing application (hereinafter referred to as an application) stored in the HDD 103 or the external storage device 108 according to a user instruction to the instruction input unit 107. Then, the application is developed in the main memory 102 and a user interface (hereinafter referred to as UI) is displayed on the monitor 105. Subsequently, various data stored in the HDD 103 and the external storage device 108 are transferred to the main memory 102 via the bus 106 based on a command from the CPU 101. Various data transferred to the main memory 102 are subjected to predetermined arithmetic processing in response to a command from the CPU 101, and the arithmetic result is displayed on the monitor 105 via the bus 106 or stored in the HDD 103 or the external storage device 108.

  FIG. 2 is a block diagram illustrating a functional configuration of the color processing apparatus according to the present embodiment. As described above, in the present embodiment, the configuration illustrated in FIG. 2 is realized as an application operation based on a command from the CPU 101. In the color processing apparatus 110 shown in FIG. 2, reference numeral 111 denotes a UI display unit that displays a UI on the monitor 105. Reference numeral 112 denotes an input unit for inputting the spectral radiance factor of the reference color under the observation light source, the spectral radiance factor of the reference color and the target color under the measurement light source, and the reflected spectral radiance factor of the reference color and the target color.

  Here, the spectral radiance factor is a value obtained by dividing the radiated light from the sample obtained when the sample is irradiated with light by the irradiated light, and is reflected from the sample as radiated light from the sample. This includes the case where the fluorescence emitted from the sample is superimposed on the light. Similarly to the spectral radiance factor, the reflected spectral radiance factor is a value obtained by dividing the radiant light from the sample obtained when the sample is irradiated with light by the irradiation light. The emitted light consists only of the reflected light from the sample, that is, does not contain fluorescence. Therefore, for the same sample, the spectral radiance factor varies depending on the light source because it depends on the amount of fluorescence generated, but the reflected spectral radiance factor does not depend on the amount of fluorescence and is constant regardless of the light source. In the present embodiment, it is assumed that the reflected spectral radiance factor is measured under a measurement light source. The reflected spectral radiance factor can be measured by, for example, a general measuring instrument as shown in FIG. That is, the sample 61 is irradiated with light that passes through the filter 65 that removes the excitation wavelength region (ultraviolet region) of the measurement light source 62, and the reflected light is received by the light receiver 64 through the spectroscope 63, whereby the reflected light is separated. Measure radiance. Then, by dividing the spectral radiance of the obtained reflected light by the spectral radiance of the measurement light source 62, the reflected spectral radiance factor of the sample 61 is calculated. The measurement light source 62 may be a light source having an intensity in the fluorescence excitation wavelength region (ultraviolet region), and is not limited to a specific light source. Can be measured. The method for measuring the reflection spectral radiance factor is not limited to this method.

  In the present embodiment, the reference color refers to a predetermined color, and the influence of fluorescence, that is, the difference between the spectral radiance factor under the observation light source and the reflected spectral radiance factor for the sample on which the reference color is printed is Any color can be used as long as it can be confirmed. The target color is a color of a sample (target color sample) that is a target of calculation of the spectral radiance factor under the observation light source in this embodiment, that is, a color other than the reference color. Hereinafter, the spectral radiance (rate) of a sample printed with a reference color (reference color sample) is simply referred to as the spectral radiance (rate) of the reference color, and the sample printed with the target color (target color sample). ) Is the same.

  Returning to FIG. 2, 113 is a fluorescence correction for calculating a fluorescence correction coefficient from the spectral radiance factor of the reference color under the measurement light source, the spectral radiance factor of the reference color under the observation light source, and the reflected spectral radiance factor of the reference color. It is a coefficient calculation part. 114 is a spectral radiance factor calculation unit that calculates the spectral radiance factor of the target color under the observation light source from the spectral radiance factor of the target color under the measurement light source, the reflected spectral radiance factor of the target color, and the fluorescence correction coefficient. is there. 115 is an output unit that outputs the spectral radiance factor of the target color under the observation light source calculated by the spectral radiance factor calculator 114 as a file. 116 holds pre-measured data of spectral radiance factor of reference color under observation light source and measurement light source, reflection spectral radiance factor of reference color, and spectral radiance factor of target color under measurement light source A spectral data holding unit. The spectral data holding unit 116 corresponds to the HDD 103 and the external storage device 108 shown in FIG.

Processing for obtaining spectral radiance factor under observation light source of target color Hereinafter, processing for obtaining a spectral radiance factor under the observation light source of target color in the color processing apparatus of the present embodiment will be described with reference to the flowchart of FIG. To do.

  First, in S1, the UI display unit 111 displays on the monitor 105 a UI for allowing the user to input information necessary for information processing. An example of the UI displayed here is shown in FIG. In the UI shown in FIG. 5, 1001, 1002, and 1003 are files of the spectral radiance factor of the reference color under the observation light source, the spectral radiance factor of the reference color under the measurement light source, and the reflected spectral radiance factor of the reference color, respectively. An instruction input unit for indicating a name. Reference numerals 1004 and 1005 denote instruction input units for instructing the file names of the spectral radiance factor of the target color and the reflected spectral radiance factor of the target color under the measurement light source. Reference numeral 1006 denotes an instruction input unit for instructing a file name for storing the spectral radiance factor of the target color under the observation light source calculated by the color processing apparatus 110. Reference numeral 1007 denotes a button for instructing the color processing apparatus 110 to execute processing, and when the button is pressed, the processing proceeds to S2. Note that the UI shown in FIG. 5 is merely an example, and any UI may be used as long as it can input a spectral radiance factor.

  In S2, the input unit 112 receives the spectral radiance factor of the reference color under the observation light source from the spectral data holding unit 116 based on the file name specified by the instruction input unit 1001 in the UI displayed in S1 (under the observation light source reference). (Brightness rate). Similarly, in S3, the spectral radiance factor of the reference color under the measurement light source (the reference luminance factor under the measurement light source) is input based on the file name designated by the instruction input unit 1002 of the UI. Similarly, in S4, the reflection spectral radiance factor (reference reflectance) of the reference color is input based on the file name specified by the instruction input unit 1003 of the UI. FIG. 6 shows the data structure of each spectral radiance factor input at S2, S3, and S4. As shown in FIG. 6, each radiance factor for a wavelength of 10 nm interval from 380 nm to 780 nm is indicated by the user.

  Next, in S5, the fluorescence correction coefficient calculation unit 113 calculates a fluorescence correction coefficient from each spectral radiance factor and reflected spectral radiance factor of the reference color input in S2, S3, and S4. Details of the fluorescence correction coefficient calculation processing in S5 will be described later.

  In S6, the input unit 112 determines the spectral radiance factor of the target color under the measurement light source (the luminance under the measurement light source) from the spectral data holding unit 116 based on the file name designated by the UI instruction input unit 1004 displayed in S1. Rate). Similarly, in S7, the reflection spectral radiance factor (reflectance) of the target color is input based on the file name specified by the instruction input unit 1005 of the UI. Note that the spectral radiance factor and the reflected spectral radiance factor of the target color input in S6 and S7 also have a data structure as shown in FIG. (The data structure of the spectral radiance factor of the target color was also described as being the same as in Figure 6.)

  In S8, the spectral radiance factor calculation unit 114 calculates the target color under the observation light source from the spectral radiance factor and the reflected spectral radiance factor of the target color input in S6 and S7 and the fluorescence correction coefficient calculated in S5. Spectral radiance factor (brightness factor under observation light source) is calculated. Details of the spectral radiance factor calculation processing in S8 will be described later.

● Fluorescence correction coefficient calculation processing (S5)
Hereinafter, the fluorescence correction coefficient calculation process in S5 will be described in detail with reference to the flowchart of FIG.

  First, in S501 and S502, the spectral radiance factor of the reference color under the measurement light source input in S3 and the reflected spectral radiance factor of the reference color input in S4 are acquired. In S503, an increase in the spectral radiance factor due to fluorescence under the measurement light source is acquired from the spectral radiance factor acquired in S501 and the reflected spectral radiance factor acquired in S502. Here, FIG. 8 shows the concept of the amount of increase in the spectral radiance factor due to fluorescence. In FIG. 8, the broken line indicates the spectral radiance factor acquired in S501, and the solid line indicates the reflected spectral radiance factor acquired in S502. The hatched portion shown in FIG. 8 is a component obtained by subtracting the reflected spectral radiance factor from the spectral radiance factor, and corresponds to an increase in the spectral radiance factor due to fluorescence.

  Next, in S504, the spectral radiance factor of the reference color under the observation light source input in S2 is acquired. In S505, the amount of increase in the spectral radiance factor due to fluorescence under the observation light source is acquired from the spectral radiance factor acquired in S504 and the reflected spectral radiance factor acquired in S502. The increase amount acquired here is obtained by subtracting the reflected spectral radiance factor acquired in S502 from the spectral radiance factor acquired in S504.

  Next, in S506, the increase amount ΔF1 (λ) of the spectral radiance factor due to the fluorescence under the observation light source acquired in S505 and the increase amount ΔF2 (λ of the spectral radiance factor due to the fluorescence under the measurement light source acquired in S503. ) And k (λ) are calculated by the following equation (2). That is, k (λ) is the ratio of the amount of fluorescence generated under the observation light source and the measurement light source.

k (λ) = ΔF1 (λ) / ΔF2 (λ) (2)
Here, in general, the relative spectral distribution (fluorescence spectrum) of fluorescence under each light source mainly depends on the spectral whitening agent contained in the medium and the spectral transmittance of the printed color (ink). Therefore, when the media type and printing color are uniquely determined, the relative spectral distribution of fluorescence can also be uniquely determined regardless of the light source. Therefore, the relative spectral distributions of the increase amounts ΔF1 (λ) and ΔF2 (λ) of the spectral radiance factor due to the fluorescence only in the light source can be considered to be substantially the same regardless of the light source. Therefore, the ratio k (λ) shown in the above equation (2) can be treated as a constant K as in the following equation (3).

K = ΔF1 (λ) / ΔF2 (λ) (3)
In this embodiment, the constant K in Equation (3) is applied when converting the amount of increase in spectral radiance factor due to fluorescence under the measurement light source into the amount of increase in spectral radiance factor due to fluorescence under the observation light source. Fluorescence correction coefficient. If the fluorescence spectrum differs depending on the light source, that is, if the ratio k (λ) cannot be treated as a constant, the function k (λ) having the wavelength λ as a variable as shown in Equation (2) is used as the fluorescence correction coefficient. To do.

Spectral radiance factor calculation process (S8)
Hereinafter, the calculation process of the spectral radiance factor in S8 will be described in detail using the flowchart of FIG. 9 and the spectral radiance factor example of FIG. FIG. 10 shows the concept of the method for calculating the spectral radiance factor of the target color, (a), (b) is the spectral radiance factor under the measurement light source and the observation light source with respect to the reference color, (c) , (d) shows the spectral radiance factor under the measurement light source and the observation light source for the target color. In each figure of FIG. 10, the broken line indicates the spectral radiance factor, and the solid line indicates the reflected spectral radiance factor. For the sake of explanation, the difference between the spectral radiance factor and the reflected spectral radiance factor is sufficiently large in each figure. The wavelength is indicated by a chain line.

  First, in S801, the spectral radiance factor of the target color under the measurement light source input in S6 (corresponding to the broken line in FIG. 10 (c)) is obtained, and in S802, the reflected spectral radiance factor of the target color input in S7 ( (Corresponding to the solid line in FIG. 10 (c)). In S803, by subtracting the reflected spectral radiance factor acquired in S802 from the spectral radiance factor acquired in S801, the amount of increase in the spectral radiance factor due to fluorescence under the measurement light source (of FIG. 10 (c)). (Corresponding to the shaded area).

  Next, in S804, the fluorescence correction coefficient calculated in S5 (corresponding to the ratio of ΔF1 (λ) in FIG. 10B and ΔF2 (λ) in FIG. 10A) is acquired.

  In step S805, the spectral radiance factor of the target color under the observation light source is calculated. Specifically, the fluorescence correction coefficient is first multiplied by the amount of increase in spectral radiance factor (corresponding to the shaded portion in FIG. 10C) obtained by fluorescence under the measurement light source of the target color obtained in S803. As a result, the amount of increase in the spectral radiance factor due to fluorescence under the observation light source of the target color (corresponding to the hatched portion in FIG. 10 (d)) is acquired. Then, with respect to the reflected spectral radiance factor acquired in S802 (corresponding to the solid line in FIGS. 10 (c) and 10 (d)), the amount of increase in the spectral radiance factor due to fluorescence under the observation light source of the target color (FIG. 10 (d ) Is equivalent to the shaded area. As a result, the spectral radiance factor of the target color under the observation light source (corresponding to the broken line in FIG. 10 (d)) is acquired.

  As described above, according to the present embodiment, when measuring the spectral radiance factor under the observation light source, first, a sample consisting of one reference color is measured under the measurement light source and the observation light source. Thus, a fluorescence correction coefficient indicating the ratio of the amount of generated fluorescence is calculated. For a sample of any target color, the spectral radiance factor under the observation light source can be calculated in a short time by multiplying the fluorescence increase factor in the spectral radiance factor under the measurement light source by the fluorescence correction coefficient. Can do.

Second Embodiment
Hereinafter, a second embodiment according to the present invention will be described. In the first embodiment described above, an application for calculating the spectral radiance factor of the target color under the observation light source is executed based on the spectral data stored in the spectral data holding unit 116 (HDD 103 or external storage device 108). An example is shown. In the second embodiment, the spectral radiance factor of a desired target color is determined based on the measurement result by controlling an external measuring device based on an instruction from the application, not on the spectral data stored in advance. It is characterized by calculating.

  FIG. 11 is a block diagram illustrating a hardware configuration of the color processing apparatus according to the second embodiment. The configuration shown in the figure is substantially the same as the configuration shown in FIG. 1 in the first embodiment described above, but is characterized in that the measuring instrument 109 is further connected to the main bus 106 via the general-purpose interface 104. In the following, differences from the first embodiment will be described in particular, and descriptions of similar configurations and operations will be omitted. FIG. 12 is a block diagram illustrating a functional configuration of the color processing apparatus according to the second embodiment. This configuration is realized as an application operation based on a command from the CPU 101, as in the first embodiment. The color processing apparatus 210 shown in FIG. 12 has an external device control unit 217 that controls the measuring instrument 109 as a device driver on a general-purpose OS, compared to the configuration shown in FIG. 2 in the first embodiment. It is characterized by that. Further, the operation of the input unit 212 is different from that of the first embodiment.

  Hereinafter, the spectral radiance factor acquisition process in the color processing apparatus according to the second embodiment will be described. The process follows the flowchart of FIG. 4 as in the first embodiment described above. In the second embodiment, the content of the UI displayed in S1, the method of acquiring the spectral radiance factor of the target color under the measurement light source, and the reflected spectral radiance factor of the target color acquired in S6 and S7 However, this is different from the first embodiment.

  First, an example of a UI displayed on the monitor 105 by the UI display unit 211 in S1 is shown in FIG. The UI shown in FIG. 13 is characterized by having measurement buttons 2004 and 2005 instead of the instruction input units 1004 and 1005 in the UI shown in FIG. 5 in the first embodiment. The measurement buttons 2004 and 2005 are buttons for instructing measurement of the spectral radiance factor of the target color and the reflected spectral radiance factor of the target color under the measurement light source, respectively. When the measurement button 2004 is pressed by the user, the input unit 212 instructs the external device control unit 217 to control the measuring instrument. Upon receiving the instruction, the external device control unit 206 controls the measuring device 109 connected to the general-purpose interface 104, and acquires the spectral radiance factor by measuring the spectral radiance of the target color under the measurement light source. Similarly, when the measurement button 2005 is pressed by the user, the input unit 212 instructs the external device control unit 217 to control the measuring instrument. Upon receiving the instruction, the external device control unit 217 controls the measuring device 109 connected to the general-purpose interface 104 to measure the reflected spectral radiance of the target color, thereby acquiring the reflected spectral radiance factor. Each spectral radiance factor measured as described above is input by the input unit 212 as the data structure described with reference to FIG. Note that the process of converting each spectral radiance measurement data into the spectral radiance factor data structure shown in FIG. 6 may be executed by the external device control unit 217 or the input unit 212.

  After inputting the spectral radiance factor under the measurement light source of the target color as described above, the processing of S8 is performed as in the first embodiment to calculate the spectral radiance factor under the observation light source of the target color. can do.

  As described above, according to the second embodiment, the color under the observation light source in consideration of the fluorescence of the sample can be obtained with high accuracy by executing the measurement application in the color processing apparatus connected to the measuring instrument. it can.

<Third Embodiment>
The third embodiment according to the present invention will be described below. In the first and second embodiments described above, the color processing apparatus has been shown in which the CPU 101 acquires a spectral radiance factor of a target color at high speed by operating a predetermined application. In the third embodiment, an example is shown in which the color processing device in each of the above embodiments is applied as a color correction profile creation device that creates a color correction profile between a monitor and a printer.

  FIG. 14 shows a functional block configuration of the color correction profile creation device in the third embodiment. In the color correction profile creation device 1601 shown in the figure, the observation environment light setting unit 1605 sets the observation environment light. The observation environment light setting unit 1605 checks whether or not the reproduction color gamut data of the monitor or printer in the set observation environment light is stored in the input color gamut data storage unit 1603 and the output color gamut data storage unit 1604. . When the reproduction color gamut data under the observation environment light is not stored, the measurement unit 1602 newly acquires the reproduction color under the observation environment light. That is, in the third embodiment, the measurement unit 1602 is realized as the color processing apparatus of the first or second embodiment. That is, the spectral radiance factor of the desired color under the observation light source is calculated as in the first embodiment, or is calculated by the minimum measurement using a measuring instrument as in the second embodiment. The reproduction color gamut data of the monitor or printer under the observation environment light measured by the measurement unit 1602 is stored in the input color gamut data storage unit 1603 and the output color gamut data storage unit 1604, respectively. The mapping unit 1606 performs color matching processing between the reproduction color gamuts of the monitor and the printer, and the profile creation unit 1607 creates a color correction profile under the observation sightseeing light based on the color matching result.

  As described above, according to the third embodiment, when a color correction profile is created, the profile can be created at high speed by acquiring the spectral radiance factor for the desired color at high speed.

<Other embodiments>
In each of the above embodiments, an example has been shown in which various spectral radiance factors measured in advance by an external device are acquired by the color processing device. However, the color processing device is realized by a device having both an arithmetic function and a measurement function. Each measurement may be performed in the device. For example, a measuring instrument having a calculation function, a handy type computer having a measurement function, or the like corresponds to a device having both the calculation function and the measurement function.

In each of the above embodiments, the spectral radiance factor is output. However, other color reproduction characteristics can be output. For example, in order to directly calculate the spectral radiance under the observation light source, using the spectral radiance of the sample obtained by multiplying all the spectral radiance rates input in the above embodiments by the spectral radiance of each light source, You may perform the process similar to each embodiment. At this time, the amount of increase in the spectral radiance rate due to fluorescence is calculated as the amount of increase in spectral radiance, and the fluorescence correction factor is calculated as the ratio of the amount of increase in spectral radiance of fluorescence. The Furthermore, a colorimetric value may be calculated and output using an observation light source and color matching function acquired from the outside or by measurement, and the spectral radiance factor acquired by the above embodiments. At this time, the colorimetric value may be converted into a perceptual space value such as CIE tristimulus values XYZ, CIELAB, CIECAM02, and the like. It is also possible to output in the form of a color profile created using the colorimetric values. The color profile is a profile used in the color management system, and describes the color reproduction characteristics of the device. For example, in a general color profile of an RGB printer, the correspondence relationship between RGB and XYZ (CIELAB, CIECAM02) of color charts of 729 (9 ³ ) colors in total of 9 steps for each RGB is described as an LUT. Therefore, it is possible to calculate the XYZ of each color from the total spectral radiance factor of each color and the spectral radiance factor of the observation light source acquired in each of the above embodiments, and create a color profile.

  Further, in each of the above embodiments, an example is shown in which the fluorescence correction coefficient is calculated from the spectral radiance factor of the reference color under the observation light source, the spectral radiance factor of the reference color under the measurement light source, and the reflected spectral radiance factor. However, the method for acquiring the fluorescence correction coefficient is not limited to this example. For example, since the fluorescence correction coefficient is generally determined according to the medium containing the fluorescent brightening agent and the observation light source, the fluorescence correction coefficient is calculated in advance for a combination of a plurality of media and the observation light source, and is provided as a database. Also good. Further, the fluorescence correction coefficient may be directly input by the user.

  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 processor (or CPU, MPU, etc.) of the system or apparatus reads the program. It is a process to be executed.

Claims (7)

A measurement light source for obtaining a spectral radiance factor based on reflected light and fluorescence from a reference color sample measured under a measurement light source for a reference color sample printed with a predetermined reference color as a reference luminance rate under the measurement light source Means for obtaining a lower reference luminance rate;
A reference reflectance acquisition means for acquiring, as a reference reflectance, a spectral radiance factor based on only reflected light from the reference color sample, measured under the measurement light source for the reference color sample;
An observation light source reference luminance rate acquisition means for acquiring a spectral radiance factor based on reflected light and fluorescence from the reference color sample measured as an observation light source for the reference color sample, as an observation light source reference luminance rate;
A fluorescence correction coefficient indicating a ratio of the amount of fluorescence generated from the reference color sample under the measurement light source and the observation light source from the measurement light source reference luminance rate, the observation light source reference luminance rate, and the reference reflectance. A fluorescence correction coefficient calculating means for calculating;
A spectral radiance factor based on reflected light and fluorescence from the target color sample measured under the measurement light source for a target color sample printed with a target color different from the reference color is acquired as a luminance rate under the measurement light source. Means for obtaining the luminance factor under the measurement light source;
Reflectance acquisition means for acquiring a spectral radiance factor based on only the reflected light from the target color sample, measured under the measurement light source for the target color sample,
Based on the difference between the luminance factor under the measurement light source and the reflectance and the fluorescence correction coefficient, the luminance factor under the observation light source that calculates the spectral radiance factor of the target color sample under the observation light source as the luminance factor under the observation light source have a and of the calculation means,
The reference reflectance acquisition means and the reflectance acquisition means are measured by irradiating the reference color sample and the target color sample with light obtained by removing an ultraviolet region from the emitted light of the measurement light source. A color processing apparatus that acquires a reflectance and the reflectance .   The fluorescence correction coefficient calculation means calculates the fluorescence correction coefficient as a ratio of a difference between the reference luminance ratio under the measurement light source and the reference reflectance and a difference between the reference luminance ratio under the observation light source and the reference reflectance. The color processing apparatus according to claim 1, wherein: Furthermore, it has holding means for holding in advance the respective data of the reference luminance ratio under the measurement light source, the reference luminance ratio under the observation light source, the reference reflectance, the luminance ratio under the measurement light source, and the reflectance,
The measurement light source lower reference luminance rate acquisition means, the reference reflectance acquisition means, the observation light source lower reference luminance rate acquisition means, the measurement light source lower luminance ratio acquisition means, and the reflectance acquisition means, the color processing apparatus according to claim 1 or 2, characterized in that to obtain the data held in the holding means. Furthermore, it has holding means for holding in advance each data of the reference luminance rate under the measurement light source, the reference luminance rate under the observation light source, and the reference reflectance,
The measurement light source lower reference luminance rate acquisition unit, the reference reflectance acquisition unit, and the observation light source lower reference luminance rate acquisition unit each acquire the data held in the holding unit. The color processing apparatus according to claim 1 or 2 . Furthermore, it has a measuring means for measuring the spectral radiance of the target color sample,
Said acquisition means acquiring means and the reflectance of the measurement light source under the luminance ratio, according to claim 4, characterized in that the basis of the by the measuring result measuring means, obtains the measurement light source under luminance factor and the reflectance Color processing equipment. Means for obtaining reference luminance ratio under measurement light source, means for obtaining reference reflectance, means for obtaining reference luminance ratio under observation light source, means for calculating fluorescence correction coefficient, means for obtaining luminance ratio under measurement light source, means for obtaining reflectance, and observation A color processing method in a color processing apparatus having a luminance rate calculation means under a light source,
Spectral radiance factor based on reflected light and fluorescence from the reference color sample measured by the measurement light source for the reference color sample printed with a predetermined reference color under the measurement light source. As the reference luminance rate under the measurement light source,
The reference reflectance acquisition means acquires, as a reference reflectance, a spectral radiance factor based on only reflected light from the reference color sample, measured under the measurement light source for the reference color sample,
The means for obtaining a reference luminance rate under the observation light source obtains a spectral radiance factor based on reflected light and fluorescence from the reference color sample, measured under the observation light source for the reference color sample, as a reference luminance rate under the observation light source. And
The fluorescence correction coefficient calculation means calculates the amount of fluorescence generated from the reference color sample under the measurement light source and under the observation light source from the measurement light source reference luminance rate, the observation light source reference luminance rate, and the reference reflectance. A fluorescence correction coefficient indicating the ratio of
Spectral radiation based on reflected light and fluorescence from the target color sample measured under the measurement light source for the target color sample printed with the target color different from the reference color Obtain the luminance rate as the luminance rate under the measurement light source,
The reflectance acquisition means acquires, as a reflectance, a spectral radiance factor based on only the reflected light from the target color sample, measured under the measurement light source for the target color sample,
The means for calculating the luminance factor under the observation light source calculates the spectral radiance factor of the target color sample under the observation light source based on the difference between the luminance factor under the measurement light source and the reflectance and the fluorescence correction coefficient. Calculated as the lower luminance rate ,
The reference reflectance acquisition means and the reflectance acquisition means are measured by irradiating the reference color sample and the target color sample with light obtained by removing an ultraviolet region from the emitted light of the measurement light source. A color processing method characterized by acquiring a reflectance and the reflectance . Program for causing to function as each means of a color processing apparatus according to computer in any one of claims 1 to 5.

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