JP2001145122A - System and method for profile generation, digital photographing device, and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower the profile generation cost of a printer. SOLUTION: A reference image is printed by a printer 9 and the print contents are photographed by a digital camera 2 with its flash 'ON' and 'OFF', respectively. The obtained image data are transferred to a computer 3 to find body color component data, showing the spectral reflection factor of the print contents and image data, when the print contents are lightened up with standard light (D50) are generated. Then the generated image data are compared with the data of the reference image to generate the profile of the printer 9. Consequently, the profile can be generated without using expensive dedicated measuring instrument and the profile generation cost is suppressed low.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a technique for creating a profile for correcting a print color of a printer.

[0002]

2. Description of the Related Art Conventionally, in order to make print colors of a color printer proper, a profile is stored in a computer for controlling the printer, and the print colors of the printer are corrected.

Here, in order to make the profile appropriate, that is, in order to perform color matching of a printer, a reference image is usually printed, and the print result is measured by a dedicated measuring instrument. The profile is created by processing the measurement results on a computer on which a dedicated program is executed.

On the other hand, as disclosed in Japanese Patent Application Laid-Open No. H11-120337, a technique has been proposed in which a printed reference image is read by a scanner to create a printer profile.

[0005]

However, when a profile of a printer is created by using a dedicated measuring instrument and a program, there is a problem that the cost of creating a profile is high. The system is not easily implemented.

When a printer profile is created by using a scanner, it is assumed that the profile of the scanner is appropriate. However, the light source characteristics of the scanner differ between when the power is turned on and after a certain period of time. In addition, long-term use causes a change with time. Therefore, complicated work is actually required to keep the scanner profile in an appropriate state.

Accordingly, the present invention has been made in view of the above problems, and has as its object to create an appropriate profile of a printer quickly and inexpensively using a digital photographing apparatus.

[0008]

According to a first aspect of the present invention, there is provided a profile creating system for creating a profile for correcting a printing color of a printer, wherein a profile printed by the printer is photographed in accordance with predetermined reference image data. A digital photographing apparatus for acquiring photographed image data by calculating the object color component data obtained by removing the influence of illumination light from the photographed image data; and a profile of the printer from the reference image data and the object color component data. And a profile creation unit for creating a profile.

According to a second aspect of the present invention, in the profile creation system according to the first aspect, the digital photographing device has a flash for emitting a flash light toward a photographing target, and the photographed image data includes the flash. First image data obtained by photographing the print content by emitting a flash, and second image data obtained by photographing the print content without emitting the flash are included, and the arithmetic unit includes: The object color component data is obtained using the first and second image data.

According to a third aspect of the present invention, there is provided a profile creating system for creating a profile for correcting a print color of a printer, wherein the profile is created based on image data obtained from print content printed by the printer in accordance with predetermined reference image data. A profile creation unit for creating a profile of the printer, and determining a difference between a parameter value related to color reproduction in the created profile and a parameter value related to color reproduction in the current profile, wherein the difference exceeds a predetermined standard. Confirmation means for displaying on the display means that the profile should be updated.

According to a fourth aspect of the present invention, in the profile creation system according to any one of the first to third aspects, the print content includes a plurality of color display areas for displaying different colors.

According to a fifth aspect of the present invention, in the profile creating system according to the fourth aspect, the print content includes a display indicating a reference of a position of the plurality of color display areas.

According to a sixth aspect of the present invention, there is provided a digital photographing apparatus, comprising: a photographing section for acquiring photographed image data by photographing print contents printed by a printer in accordance with predetermined reference image data; Computing means for obtaining object color component data from which the influence of illumination light has been removed, and profile creating means for creating a profile for correcting the printing color of the printer from the reference image data and the object color component data.

According to a seventh aspect of the present invention, there is provided the digital photographing apparatus according to the sixth aspect, further comprising a flash for emitting a flash light toward an object to be photographed, wherein the photographed image data is obtained by emitting the flash. First image data obtained by photographing the print content and second image data obtained by photographing the print content without emitting the flash are included, and the arithmetic unit includes the first and second image data. The object color component data is obtained using image data.

According to an eighth aspect of the present invention, there is provided the digital photographing apparatus according to the sixth or seventh aspect, wherein a value of a parameter relating to color reproduction in a created profile and a value of a parameter relating to color reproduction in a current profile are stored. Is further provided, wherein a confirmation means for obtaining a difference between the two, and displaying on the display means that the profile should be updated when the difference exceeds a predetermined reference.

According to a ninth aspect of the present invention, in the digital photographing apparatus according to any one of the sixth to eighth aspects, the print content includes a plurality of color display areas for displaying different colors from each other.

According to a tenth aspect of the present invention, there is provided a profile creation method for creating a profile for correcting a print color of a printer, wherein a print content printed by the printer is photographed using a digital photographing apparatus in accordance with predetermined reference image data. Obtaining the photographed image data, obtaining object color component data obtained by removing the influence of illumination light from the photographed image data, and creating the printer profile from the reference image data and the object color component data. And a process.

An eleventh aspect of the present invention is a profile creation method for creating a profile for correcting a print color of a printer, wherein the profile is created based on image data obtained from print content printed by the printer in accordance with predetermined reference image data. Step of creating a printer profile, before or after the step of creating the profile, to determine the difference between the parameter value related to color reproduction in the created profile and the parameter value related to color reproduction in the current profile, A step of displaying on the display means that the profile should be updated when the difference exceeds a predetermined criterion.

According to a twelfth aspect of the present invention, there is provided a recording medium readable by a processing device recording a program for creating a profile for correcting a printing color of a printer using the processing device, wherein the program is stored in the processing device by a predetermined program. A step of obtaining object color component data obtained by removing the influence of illumination light from photographed image data obtained by photographing a print content printed by a printer using a digital photographing device in accordance with the reference image data; and Creating a profile of the printer from the object color component data.

According to a thirteenth aspect of the present invention, there is provided a recording medium readable by a processing device which records a program for creating a profile for correcting a printing color of a printer using the processing device, wherein the program is stored in the processing device by a predetermined program. Creating a profile of the printer based on image data obtained from print content printed by a printer according to reference image data of the printer, and before or after the step of creating the profile, related to color reproduction in the created profile. Calculating a difference between the parameter value and the parameter value related to color reproduction in the current profile, and displaying that the profile should be updated when the difference exceeds a predetermined reference.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <1. First Embodiment> FIG.
FIG. 1 is a perspective view showing a configuration of a profile creation system 1 according to a first embodiment of the present invention, together with a printer 9 to be created, a printed sheet 91, and the like. A profile is data that expresses the performance and characteristics of an input / output device (the printer 9 in this embodiment). In color management, the system performs color conversion and performs color matching (that is, correction of print colors). )
This is the data to perform.

The profile creation system 1 is a digital still camera (hereinafter, referred to as a digital still camera) that acquires image data by photographing.
"Digital camera". ) 2, a computer 3 and a display 3a, and the display 3a and the printer 9 are controlled by the computer 3. The profile creation system 1 causes the computer 3 to perform calculation processing for profile creation.

In the profile creation in the profile creation system 1, the reference image is printed on the paper 91 by the printer 9, the print content of the paper 91 is photographed by the digital camera 2, and the image data obtained by the digital camera 2 Is created in the computer 3 via the memory card 4 such as a compact flash, and the profile is created. Details will be sequentially described below.

FIG. 2 is a block diagram showing a main internal configuration of the computer 3 together with the digital camera 2, the printer 9, and the like. The computer 3 is a general-purpose computer,
CPU 31 for executing arithmetic processing, ROM 32 for storing basic programs, and RA serving as a work storage area
M33 is connected to a bus line.

The bus line includes a communication interface 34 to the printer 9, a card slot 35 for transferring information to and from the memory card 4, a communication port 36 for transferring information to and from the outside, and a CD-ROM 8. CD for reading recorded profile creation program
A ROM drive 37, a video card 38 for controlling the display of the display 3a, and the like are connected via an interface as appropriate.

The RAM 33 stores a program 331 read from the CD-ROM drive 37 and reference image data 33 used for creating a profile.
2 is stored, and the first image data 333a and the second image data 333b, which are photographed image data obtained by photographing, and the profile 3 created by the CPU 31 executing arithmetic processing according to the program 331.
34 and the like are stored.

FIG. 3 is a perspective view showing the entire digital camera 2. The digital camera 2 includes a lens unit 21 that performs photographing, and a main unit 22 that processes an image acquired as digital data by the lens unit 21.

The lens unit 21 has a lens system 211 having a plurality of lenses, and a CCD 212 for acquiring an image of a subject via the lens system 211. And
The image signal output from the CCD 212 is sent to the main unit 22. The lens unit 21 has a finder 213 for the operator to capture the subject, and a distance measurement sensor 21.
4 etc. are also arranged.

The main body 22 is provided with a flash 221 and a shutter button 222. An operator captures an object through the finder 213 and operates the shutter button 222, so that an image is electrically acquired by the CCD 212. You. At this time, if necessary, the flash 221
Emits light. Note that the CCD 212 is a three-band imaging unit that acquires values for each of the colors R, G, and B as the value of each pixel.

The image signal from the CCD 212 is transmitted to the main body 22.
The processing is internally performed and stored in the memory card 4 mounted on the main body unit 22 as necessary. The memory card 4 is taken out of the main body 22 by opening the lid on the lower surface of the main body 22 and operating the eject button 224. Data stored in the memory card 4 as a recording medium can be transferred to the computer 3. Conversely, the digital camera 2 can read data stored in the memory card 4 in the card slot 35 of the computer 3.

FIG. 4 is a diagram showing a state when the digital camera 2 is viewed from behind. A liquid crystal display 225 for displaying a photographed image and displaying a menu for the operator is provided at the center of the back surface of the main body unit 22, and an input is performed on the side of the display 225 according to the menu displayed on the display 225. Operation buttons 22 for performing operations
6 are arranged. Thereby, operation of the digital camera 2, setting of shooting conditions, maintenance of an external memory, reproduction of an image, and the like can be performed.

FIG. 5 shows the configuration of the digital camera 2.
FIG. 2 is a block diagram schematically showing a configuration mainly for executing processing according to the present invention.

In the configuration shown in FIG. 5, the lens system 211,
CCD 212, A / D converter 215, correction circuit 216,
The shutter button 222, the CPU 231, the ROM 232, and the RAM 234 implement a function of acquiring an image. That is, the image of the subject is changed by the lens system 211 to the CCD 21.
2 and the shutter button 222 is pressed,
The image signal from the CCD 212 is digitally converted by the A / D converter 215. The digital image signal converted by the A / D converter 215 is subjected to γ correction and white balance correction by the correction circuit 216,
The image data is stored in M234 as captured image data. The control of these processes is performed by the CPU 231 operating according to the program 233 stored in the ROM 232.

A CPU 23 provided in the main body 22
1. ROM 232 and RAM 234 implement the function of processing images. Specifically, in accordance with the program 233 stored in the ROM 232, the CPU 231 performs image processing on the acquired image while using the RAM 234 as a work area.

The card slot 223 is connected to the RAM 234, and exchanges various data with the memory card 4 based on an input operation from the operation button 226. In addition, the liquid crystal display 225 switches the display of an image and the display of information to an operator based on a signal from the CPU 231.

The flash 221 is provided with a light emission control circuit 221a.
Is connected to the CPU 231 via the
, The light emission control circuit 221a controls the light emission characteristics of the flash 221.

In the above description, the digital camera 2
Although the description has been made on the assumption that the computer 3 and the computer 3 transfer data via the memory card 4, the data may be transferred via a communication cable. That is, a dedicated communication port is provided in the digital camera 2, or
By installing a communication card in the card slot 223, the communication port 36 of the computer 3 and the digital camera 2 can exchange data using a communication cable.

Next, the flow of a procedure for creating a profile in the profile creation system 1 will be described with reference to FIG.

First, under the control of the computer 3, the printer 9 prints a reference image according to the reference image data 332 (step S11). Thereby, the reference image 51 illustrated in FIG. In FIG.
The hatching is used to simulate the color display. The reference image 51 is an image including a plurality of rectangular color display areas 511 separated by white, and CMY (cyan, magenta, yellow) and colors having different black components are printed on each color display area 511. Is displayed. Note that the bottom row in FIG. 7 is a color display area 512 that changes from white to black. In addition, reference marks 513, which are indications serving as references for the positions of the color display areas 511 and 512, are included in the four corners of the reference image 51.

FIG. 7 shows only an example of the reference image 51, and a plurality of reference images may exist. For example, when the values from 0 to 255 for each of cyan (C), magenta (M), and yellow (Y) are divided into five equal parts (six values), and all combinations of colors are output, The number of color display areas 511 is 216. of course,
If the accuracy of the profile needs to be further improved, more color display areas 511 may be used.
In such a case, reference image data 332 representing a plurality of reference images is prepared in order to make the size of each color display area 511 a size that can be photographed by the digital camera 2, and a sheet on which the reference image is printed is prepared. 91 may be plural.

When the printing of the reference image is completed, the digital camera 2 is switched to a special photographing mode for creating a profile, and photographing of the print contents is performed with the flash turned on. (Hereinafter, referred to as “first image”). That is, the flash 221 is turned on, an image is acquired by the CCD 212, and the obtained image (accurately, an image signal) is A / D
The data is sent from the conversion unit 215 to the RAM 234 and stored as first image data (step S12). At this time,
The correction based on the characteristics of the color filters provided in the CCD 212 is performed.

Normally, when photographing is performed in the digital camera 2, γ correction and white balance correction are performed by the correction circuit 216. In the special photographing mode, the correction circuit 216 is used.
Is canceled, and the image data corrected only based on the characteristics of the color filters is stored in the RAM 234. Note that the digital camera 2 having no special shooting mode may be used depending on the accuracy of the created profile and the degree of the correction function.

Next, the printing contents are photographed with the flash turned off, and an image of the paper 91 (hereinafter, referred to as a "second image") is obtained in an illumination environment having no flash light. That is, the CCD 2 can be used without using a flash.
12, an image is obtained, and the obtained image is converted to an A / D converter 2
15 and sent to the RAM 234, where the correction based on the characteristics of the color filters is performed, and then stored as the second image data (step S13). As a result, captured image data necessary for creating a profile is obtained as the first image data and the second image data.

These two shootings are performed quickly as in continuous shooting. Therefore, the shooting ranges of the first image and the second image are the same. The two shootings are performed under the same conditions of the shutter speed (the integration time of the CCD 212) and the aperture.

When there are a plurality of reference images,
Image data obtained by photographing a plurality of times using a flash is the first image data, and image data obtained by photographing a plurality of times without the use of a flash is second image data.

Here, the light emission of the flash 221 is performed so that the spectral distribution of the flash light becomes constant.
21a. FIG. 8 shows a light emission control circuit 221a.
6 is a flowchart showing a flow of the operation of FIG.

At the time of photographing with the flash ON or prior to photographing, first, the light emission control circuit 221a starts monitoring the charging voltage of the flash 221 to the flash power supply (that is, the voltage applied to the flash 221). (Step S21). Then, when it is confirmed that the charging voltage has reached a predetermined voltage (for example, 330 V) (step S22), the flash 221
To start light emission (step S2).
3).

At the same time as the start of light emission, the light emission control circuit 221a
Starts monitoring the light emission time (step S24). Thereafter, when it is confirmed that a predetermined time has elapsed from the start of light emission (step S25), light emission is stopped (step S26).

As described above, the light emission of the flash 221 is controlled so as to have a constant voltage and a constant light emission time, and the light emission characteristics of the flash 221 do not vary for each photographing. Note that the spectral distribution (spectral intensity) of the flash 221 is also kept constant by the light emission control, and this spectral distribution is stored in advance in the RAM 33 in the computer 3 as flash spectral data in the same manner as the program 331 and the reference image data 332. . To be precise, the relative spectral distribution of the flash light (a spectral distribution normalized with the maximum spectral intensity being 1; hereinafter, referred to as “relative spectral distribution”) is used as flash spectral data.

When the first image data and the second image data are stored in the RAM 234 by the two photographing operations, these image data are sent to the computer 3 via the memory card 4 or the communication cable and stored in the RAM 33. Is performed (step S14). Thereafter, the computer 3 performs a process of creating a profile of the printer 9.

FIG. 9 shows the CPU 31 and the RO of the computer 3.
FIG. 4 is a block diagram illustrating a functional configuration realized by operating an M32, a RAM 33, and the like according to a profile creation program 331, together with data inside the RAM 33. FIG. 9 illustrates functions realized by the CPU 31 and the like for the difference image generation unit 301, the object color component data generation unit 302, the image reproduction unit 303, and the profile generation unit 304.

In the computer 3, first, the difference image generation unit 301 obtains difference image data 341 by subtracting the second image data 333b from the first image data 333a transferred by the memory card 4 (step S15). Thereby, the second value is obtained from the values of R, G, and B of each pixel of the first image.
The R, G, and B values of the corresponding pixels of the image are respectively subtracted, and a difference image between the first image and the second image is obtained.

Next, the difference image data 341 and the flash spectral data 3
The component obtained by removing the influence of the lighting environment from the second image using 42 is obtained as object color component data 343,
33 (step S16). The object color component data 343 is data substantially corresponding to the spectral reflectance of the print content of the paper 91 as the subject. The principle of calculating the spectral reflectance of the subject from the difference image data 341 and the flash spectral data 342 that is the relative spectral distribution of the flash light will be described later.

When the object color component data 343 is obtained, the third image data 345 is generated by the image reproducing unit 303 using the illumination component data 344 (step S17).
Here, the spectral distribution of the standard light D50 is used as the illumination component data 344, the spectral reflectance of the print content of the sheet 91 is multiplied by the spectral distribution of the standard light D50 by the image reproducing unit 303, and the print content is standardized by the standard light D50. Third image data 345 obtained when illuminated is generated inside the computer 3.

After that, by comparing the reference image data 332 and the third image data 345, each color display area 5 is displayed.
11 (In the following description, the print content of the third image data 345 is also described using the reference numerals given in FIG. 7)
, A table in which the color values in the reference image data 332 and the color values in the third image data 345 are associated with each other. Then, the profile 334 of the printer 9 is created by referring to the table (step S18).

The profile is preferably created as an ICC profile according to the ICC format in order to enhance versatility, but may be created according to a dedicated format. In the ICC profile, a tag is set for each data item,
Tags used on input devices or output devices are changed. Since the printer 9 is an output device, a multidimensional table for converting a theoretical value to be output into an appropriate output value is required. That is, in the above step S18, a multidimensional table for color conversion is obtained from the theoretical value and the measured value in each color display area 511. Note that the color display area 511 is obtained from the third image data 345.
A specific example of obtaining the actual measurement value of the color will be described later.

By updating the existing profile using the profile created as described above, the print content to be printed by the printer 9 thereafter becomes the print content in which color matching is achieved.

Next, the principle of determining the spectral reflectance of the print content of the paper 91 as the object as the object color component data 343 from the difference image data 341 and the flash spectral data 342 in step S16 of FIG. 6 will be described.

First, the spectral distribution of illumination light (illumination light in an illumination environment including direct light and indirect light from a light source) for illuminating an object is represented by E (λ) (λ: wavelength in a visible region). And the spectral distribution E (λ) is divided into three basis functions E
₁ (λ), E ₂ (λ), E ₃ (λ) and weighting factors ε ₁ , ε ₂ , ε ₃
Using,

[0060]

(Equation 1)

Similarly, the spectral reflectance of a position on a subject corresponding to a certain pixel (hereinafter, referred to as “target pixel”) is represented by S (λ) and three basis functions S ₁ (λ) and S _2. (λ), S
₃ (λ) and weighting factors σ ₁ , σ ₂ , σ ₃

[0062]

(Equation 2)

When expressed as follows, light I (λ) incident on a target pixel on the CCD 212 (incident light when a filter or the like in the lens unit 21 is ignored) is

[0064]

(Equation 3)

Is expressed as follows. In addition, R, G,
Assuming that the values for each color of B are ρ _R , ρ _G , and ρ _B , and that the values obtained by converting these values into the XYZ color system are ρ _X , ρ _Y , and ρ _Z , the XYZ table Conversion to color system

[0066]

(Equation 4)

Is performed. And ρ _X , ρ _Y , ρ _Z
Is calculated using color matching functions R _X (λ), R _Y (λ), and R _Z (λ).

[0068]

(Equation 5)

Is expressed as follows.

Here, any one of ρ _X , ρ _Y , and ρ _Z of the target pixel of the first image with flash ON is ρ _c1 , and the corresponding value of the second image with flash OFF is ρ _c2 . ,
If the corresponding color matching function is R _c (λ), the corresponding value ρ _s of the difference image is

[0071]

(Equation 6)

Is obtained. Where I ₁ (λ) is the flash O
The light incident on the target pixel at the time of N, ε ₁₁ , ε ₁₂ , ε
_Reference numeral ₁₃ denotes a weighting coefficient of a basis function for illumination light including flash light. Similarly, I ₂ (λ) is the light incident on the target pixel when the flash is turned off, and ε ₂₁ , ε ₂₂ , and ε ₂₃ are the weighting coefficients of the basis functions for the illumination light not including the flash light. Furthermore, ε _si (i = 1, 2, 3) is (ε _1i −
ε _2i ).

In Equation 6, the basis functions E _i (λ) and S _j (λ)
Is a predetermined function, and the color matching function R _c (λ) is a predetermined function. Such information is stored in the ROM 32 in advance.
And stored in the RAM 33. On the other hand, in two shootings, the shutter speed (or the integration time of the CCD 212) and the aperture are controlled to be the same, and a difference image obtained by subtracting the second image from the first image is an image affected only by the change in the illumination environment. That is, since this corresponds to an image using only the flash light as the illumination light source, the weighting coefficient ε _si can be derived from the relative spectral distribution of the flash light by a method described later.

Therefore, in the equation shown in Equation 6, the unknowns are only three weighting coefficients σ ₁ , σ ₂ , and σ ₃ . The equation shown in Equation 6 is ρ _X , ρ _Y , ρ at the target pixel.
It can be obtained for each of the three stimulus values of _Z. By solving these three equations, three weighting coefficients σ ₁ , σ ₂ , and σ ₃ can be obtained. That is, the spectral reflectance at the position on the subject corresponding to the target pixel is obtained.

Next, a method for _obtaining the weighting coefficient ε _si will be described. As described above, the difference image corresponds to an image using only flash light as illumination light, and the relative spectral distribution of illumination light in the difference image is known. Meanwhile, flash 221
The area on the subject far from the camera 221 receives the flash light less than the area near the flash 221. Therefore, in the difference image, the position farther from the flash 221 appears darker.

However, when photographing the paper 91, the distance from the digital camera 2 to the paper 91 can be regarded as being constant, so that the intensity of the flash light is assumed to be uniform over the entire paper 91. Can be
The weighting coefficient ε _si can be obtained based on the output of the distance measurement sensor 214.

The weighting coefficient ε _si is a value indicating the spectral distribution of the flash light applied to the position on the subject corresponding to the target pixel, and changes the illumination light by the flash 221 between the first image and the second image. This is a value indicating the spectral distribution of the quantity. Therefore, the process of _{calculating the} weighting coefficient ε _si from the flash spectral data 342 corresponds to the process of calculating the spectral change amount of the illumination environment (illumination light) by the flash 221 from the relative spectral distribution of the flash light.

Based on the above principle, the object color component data generation unit 302 of the computer 3 refers to the pixel value of the difference image data 341 and the flash spectral data 342 to obtain the spectral data of each position on the sheet 91 corresponding to each pixel. Find the reflectance. The spectral reflectance of the print content of the paper 91 corresponds to image data from which the influence of the illumination environment has been removed, and is stored in the RAM 33 as object color component data 343.

When the object color component data 343 is obtained,
As described above, the third image data 345, which is the image data of the paper 91 illuminated by the standard light (D50), is obtained by performing the calculation represented by Expression 7 in the image reproducing unit 303 (step S17).

[0080]

(Equation 7)

Where ρ _X , ρ _Y , ρ _Z are pixel values of one pixel (target pixel) in the third image data 345, E (λ) is a spectral distribution of standard light, σ
₁ , σ ₂ , and σ ₃ are three weighting coefficients expressing the spectral reflectance at the position corresponding to the target pixel on the subject.

Next, a specific example of the process of creating a profile of the printer 9 based on the reference image data 332 and the third image data 345 (step S18) will be described. FIG. 10 is a flowchart showing an example of step S18.

In the creation of a profile, first, each color display area 511 is extracted from the third image data 345 (step S181). At this time, the fiducial mark 51
3 (see FIG. 7) is performed.
The color display area 511 is extracted with reference to the position of No. 3. Thus, for example, shooting is performed in a state where the arrangement direction of the pixels of the CCD 212 does not match the arrangement direction of the color display area 511 of the paper 91, or the imaging optical axis of the digital camera 2 is not perpendicular to the paper 91. Even if the third
The color display area 511 can be appropriately extracted from the image data 345. Since each color display area 511 is partitioned by white, four corners of the rectangular area partitioned by white are extracted, and then the color display areas 511 arranged at a predetermined pitch are extracted. It may be.

Next, in each of the color display areas 511, abnormal pixels having colors that are significantly different from the colors of the surrounding pixels are excluded from the subsequent calculation, and an effective area is obtained (step S182). For example, when the distance between the coordinates of each pixel in the color display area 511 in the XYZ color space and the average of the coordinates of the eight neighboring pixels is equal to or greater than a predetermined value, the target pixel is excluded from the color display area 511. You.

After the effective area is determined, the XYZ stimuli of all effective pixels (or a fixed size within the color display area 511, for example, 30 × 30 pixels) in each color display area 511 are next determined. By calculating an average value of the values, a value of a color representative of each color display area 511 (hereinafter, referred to as an “actually measured value”) is calculated (step S183).

On the other hand, the computer 3 specifies the theoretical value of the color of each color display area 511 based on the reference image data 332 (step S184). That is, from the position of the color display area 511 in the third image data 345, the color information output from the computer 3 to the printer 9 from the position of the color display area 511 (CMY value or XYZ value based on the CMY value) ) Is specified. Step S18
Step 4 may be performed at any stage between step S181 and step S185.

When the measured values and the theoretical values of the color information of each color display area 511 are obtained, a table in which these values are associated is created (step S185). Then, an LUT is generated as color conversion data according to the ICC profile standard with reference to the table. Note that data other than the LUT may be generated according to the type according to the standard. For example, color information corresponding to the maximum density of each color of CMY may be subjected to XYZ conversion, and a γ curve or the like of each color may be obtained, and these data may be used as data for color conversion.

When the data for color conversion is generated, a profile 334 incorporating this data is created (step S186).

Next, as an operation of the computer 3 after the creation of the profile, a description will be given of updating the profile which overwrites the created profile 334 on the existing profile.

FIG. 11 is a flowchart showing the flow of the operation of the computer 3 in updating the profile. When the profile 334 is created, first, the profile 334 is created.
, The value of a parameter relating to color reproduction of the printer 9 (hereinafter, referred to as “color reproduction parameter”) is obtained (step S31). As the color reproduction parameter, for example, YMC
The maximum density of RGBBW (yellow, magenta, cyan, red, green, blue, black, white), the γ curve of these colors, and the like are used. The value of the color reproduction parameter may be obtained by performing a predetermined operation according to the format of the data for color conversion included in the profile. Subsequently, the values of the color reproduction parameters in the currently used profile are similarly obtained (step S3).
2).

Thereafter, the difference between the value in the profile created for each type of color reproduction parameter and the value in the existing profile is determined (step S33), and one of the differences in the value of the color reproduction parameter is determined by a predetermined reference value. Is determined (step S34). For example, when calculating the difference between the maximum densities of a certain color, the maximum density in the created profile and the maximum density in the currently used profile are converted into the L ^* a ^* b ^* color system, and are expressed by Expression 8. Then, the color difference ΔE ^* is compared with a predetermined reference value.

[0092]

(Equation 8)

However, in equation 8, L ^* ₁ , a ^* ₁ , b ^* ₁
And L ^* ₂ , a ^* ₂ , b ^* ₂ are the maximum densities in the created profile and the existing profile, respectively ^.
It is a value obtained by converting to a ^* b ^* color system.

If any of the differences between the color reproduction parameter values exceeds the reference value, a message indicating that the profile needs to be updated is displayed on the display 3a connected to the computer 3 (step S35). If none of the differences in the values of the color reproduction parameters exceed the reference value,
Display 3a indicates that profile update is not required
Is displayed (step S36).

If the display 3a indicates that the profile needs to be updated, the computer 3 inquires of the user whether or not to update the profile. Profile is overwritten on the existing profile, and the profile is updated (step S3).
7, S38). As a result, the value of a signal to be generated by the computer 3 when outputting an arbitrary color to the printer 9 is determined, and appropriate color matching is realized.

FIG. 12 shows the configuration of the CPU 3 in the computer 3.
1, a functional configuration realized when the ROM 32, the RAM 33, etc. perform the operation shown in FIG.
That is, it is a block diagram showing the functional configuration of the profile creation unit 304 in FIG. The functional configuration in the computer 3 includes an area detection unit 61 that extracts a color display area 511 from the third image data 345, an effective area setting unit 62 that excludes abnormal pixels in the color display area 511, and a function effective in each color display area 511. An average value calculation unit 63 for obtaining an average value of the color information of the pixel as an actual measurement value; a table creation unit 64 for creating a table of the actual measurement value and a theoretical value derived from the reference image data 332; It can be represented as a profile data generation unit 65 that generates data and thereby creates a profile.

Further, the functional configuration realized when performing the operation shown in FIG. 11 is to determine the value of the color reproduction parameter between the created profile 334 and the existing profile 334a to determine the necessity of updating the profile. Display 3
a, and an update unit 67 for performing an update process.

Note that all or a part of the functional configuration shown in FIG. 12 may be constructed as dedicated hardware.

While the configuration and operation of the profile creation system 1 have been described above, the profile creation system 1 uses the digital camera 2 to
Since the profile is created, an expensive dedicated measuring instrument is not required unlike the related art, and the profile can be easily created while keeping the profile creation cost low.

Also, in the profile creation system 1, since the reference image has a plurality of color display areas 511, the number of times of repeating the measurement is small (for one reference image, only one flash ON / OFF shooting is required). Suffices), which simplifies the work performed by a person when creating a profile, and realizes rapid profile creation.

The digital camera 2 does not have a special mechanism and has a general-purpose on-chip filter.
The digital camera 2 for creating a profile can be realized by a simple change in the specification of a digital camera having a CD.

In the above description, the object color component data 3
It has been described that the weighting factors σ ₁ , σ ₂ , and σ ₃ corresponding to each pixel are stored as 43, but the basis functions S ₁ (λ), S ₂ (λ), and S ₃ (λ ) May be stored together with it.

In the above-described embodiment, the description has been made assuming that the arithmetic processing is performed in the XYZ color system when obtaining the object color component data 343. However, the arithmetic processing may be performed in the RGB color system. In this case, the values ρ _R , ρ _G , ρ _B of the RGB colors are used as the pixel values, and the color matching function R _X
Instead of (λ), R _Y (λ), and R _Z (λ), the spectral transmittances R _R (λ), R _G (λ), and R _B (λ) of the on-chip filter for RGB.
Is used.

In the profile creation system 1,
Since the necessity of updating the profile is also determined, unnecessary updating can be prevented.

<2. Second Embodiment> FIG. 13 is a perspective view showing a use mode of a digital camera 2 according to a second embodiment of the present invention. Note that the appearance and basic configuration of the digital camera 2 are the same as those shown in FIGS. 3 to 5, and the same components as those in the first embodiment will be described with the same reference numerals.

Digital camera 2 according to second embodiment
Stores image data obtained by photographing during normal use in the memory card 4 and transfers the image data to the printer 9 by inserting the memory card 4 into the card slot 92 of the printer 9. The printer 9 reads out image data from the memory card 4 and performs printing.

Here, when performing color matching of the printer 9, unlike the first embodiment, a profile is created inside the digital camera 2 and transferred to the printer 9. That is, the CPUs 231 and R shown in FIG.
When the OM 232 and the RAM 234 operate according to the program 233, the difference image generation unit 3 shown in FIG.
01, object color component data generation unit 302, image reproduction unit 30
3 and a function similar to that of the profile creation unit 304 are realized.

The program for creating the profile, the flash spectral data, the illumination component data, and the like need not be stored in the digital camera 2 in advance, but may be stored in the RAM 234 via the memory card 4. It may be.

FIGS. 14 and 15 are flow charts showing the flow of the procedure for creating a profile of the printer 9 in the digital camera 2. FIG. First, reference image data is recorded on the memory card 4 by the digital camera 2, and
Is mounted on the printer 9 to print a reference image (step S41).

Thereafter, as in the first embodiment, the digital camera 2 is switched to the special photographing mode, the photograph is taken on the paper 91 with the flash ON, and the first image data is obtained (step S42). Subsequently, photographing of the paper 91 is performed with the flash OFF, and second image data is obtained (step S43).

When the first and second image data are obtained, the processing performed by the computer 3 in the first embodiment is performed inside the digital camera 2. That is, the first
The second image data is subtracted from the image data to obtain difference image data (step S44), and object color component data indicating the spectral reflectance of the print content is obtained from the difference image data and the relative spectral distribution of the flash light (step S45). , And the third from the object color component data and the spectral distribution of the standard light.
Image data is obtained (step S46).

When the third image data is obtained, each color display area 51 is determined based on the reference image data and the third image data.
A table is created in which actual measured values and theoretical values of one color are associated with each other, and a profile is created with reference to the table (step S51). At this time, the CPU 231, the ROM 232, and the RAM 234 in the digital camera 2
2 functions as an area detection unit 61, an effective area setting unit 62, an average value calculation unit 63, a table creation unit 64, and a profile data generation unit 65, and executes a series of processes illustrated in FIG.

When the profile is created, the same processing as that of FIG. 11 is executed, and the profile currently used by the printer 9 and the created profile should be compared to update the color reproduction parameter values to update the profile. Is confirmed, and whether the update is necessary is displayed on the display 225 of the digital camera 2 (step S52). The profile currently in use is set in advance by the digital camera 2.
It is assumed that it is stored in

If the confirmation of the update of the profile indicates that the profile should be updated, the user transfers the created profile from the digital camera 2 to the printer 9 using the memory card 4, 9, the color matching operation is completed by updating the profile (steps S53 and S5).
4).

As described above, in the digital camera 2 according to the second embodiment, the digital camera 2 has a role as a system for creating a profile. Even when image data is sent and printing is performed, the profile of the printer 9 can be updated.

In the above description, information is exchanged between the digital camera 2 and the printer 9 by using the memory card 4. However, the digital camera 2 and the printer 9 are connected by a communication cable. Information may be exchanged.

Further, even when the printer 9 is controlled by the computer 3 as shown in FIG. 1, the digital camera 2 according to the second embodiment can be used. Is transferred to the computer 3, the amount of information to be transferred can be reduced, and the profile can be updated quickly.

Further, in the case of the configuration shown in FIG. 1, the profile creation processing performed by the digital camera 2 is not limited to all the processing shown in FIG. It may be.
For example, the processing up to table creation may be performed by the digital camera 2 (steps S181 to S185), and profile creation may be performed by the computer 3 (step S186).

<3. Third Embodiment> In the first and second embodiments, after a profile is created, confirmation is made as to whether or not the profile should be updated. It is also possible to perform update confirmation before completion of profile creation.

FIG. 16 is a flowchart showing a processing flow of the computer 3 (the digital camera 2 in the case of the second embodiment) when an update is confirmed before creating a profile. 11 shows the flow of processing after the creation of the correspondence table of the actually measured values and the theoretical values of the color information (FIG. 10: step S185) in the embodiment.

When the table is created, the values of the color reproduction parameters for the profile to be created are obtained by referring to the table (step S61). Specifically, the maximum density of each color that can be printed by the printer 9 is obtained. Then, the maximum density of each color indicated by the profile in use is obtained with reference to the profile currently in use (step S62). That is, the printer 9
The color reproduction range after updating the profile and the color reproduction range when the previous profile was created are obtained.

Thereafter, a difference between the values of these color reproduction parameters is obtained (step S63). If the difference exceeds the reference value, a message indicating that the profile needs to be updated is displayed on the display 3a (or the display 225). (Steps S64 and S65). If the difference does not exceed the reference value, it is displayed that the profile need not be updated (steps S64 and S66).

Here, when the user instructs to update the profile, the profile is created with reference to the table, and the profile is updated (steps S67 to S69). That is, in the case of the first embodiment, the profile created by the computer 3 is overwritten by the existing profile, and in the case of the second embodiment, the profile created by the digital camera 2 is replaced by the digital camera 2. Is transferred to the printer 9 to overwrite the existing profile.

As described above, the update confirmation of the profile may be performed before the profile is created. That is, from the first to third embodiments, it can be said that the step of confirming the update to the created profile may be performed at any stage before or after the step of creating the profile.

<4. Modifications> Although the configurations and operations of the profile creation system 1 and the digital camera 2 according to the present invention have been described above, the present invention is not limited to the above embodiment, and various modifications are possible.

For example, in the first and second embodiments, an example has been described in which the object color component data 343 is obtained from two image data obtained by flash ON / OFF, but the object color component data 343 is obtained by another method. May be required. Specific examples include Shoji Tominaga, "Camera systems and algorithms for achieving color constancy", IEICE Technical Report PRU95-1.
1 (1995-05) (pages 77 to 84) may be used to determine the object color component data 343. That is, a plurality of image data may be obtained by performing image capturing while exchanging a plurality of filters having different wavelength bands of transmitted light, and the object color component data 343 may be obtained from the image data.

Also, in the above-described embodiment, it has been described that a profile is simply created based on a table. However, the data actually created is a portion related to color correction in the profile, and the data in this portion is stored in an existing profile. May be overwritten. That is, if a substantially new profile is created, the data actually created may be part of the profile.

In the above-described embodiment, the difference between the value of the corresponding color reproduction parameter is determined at the time of confirming the update of the profile, and the difference is compared with the reference value. May be compared with a reference value. That is, as long as a change in the characteristics of the printer 9 relating to color reproduction can be determined, any difference in the values of the corresponding color reproduction parameters may be obtained.

Further, the confirmation of the update of the profile in the above-described embodiment can be used also when the profile of the printer 9 is created by another method, for example, when the profile is created by using a dedicated measuring instrument, It can also be used when creating a profile for the printer 9 using a scanner (assuming that the profile for the scanner has been properly adjusted).

In the first embodiment, the program 331 is described as being read from the CD-ROM 8, but the recording medium for storing the program is a magnetic disk,
Another recording medium such as a magneto-optical disk may be used. Also in the second embodiment, a program for creating a profile may be read via the memory card 4.

[0131]

The first, second, sixth, seventh, tenth and twelfth aspects of the present invention.
According to the invention described in (1), the use of a digital photographing apparatus can reduce the cost of creating a profile of a printer.

According to the third, eighth, eleventh, and thirteenth aspects of the present invention, unnecessary updating of the profile can be prevented.

According to the fourth and ninth aspects of the present invention, a profile can be created quickly.

According to the fifth aspect of the invention, the color display area can be appropriately extracted.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a profile creation system according to a first embodiment of the present invention together with a printer.

FIG. 2 is a block diagram illustrating an internal configuration of a computer.

FIG. 3 is a perspective view illustrating an appearance of the digital camera.

FIG. 4 is a rear view of the digital camera.

FIG. 5 is a block diagram illustrating an internal configuration of the digital camera.

FIG. 6 is a flowchart showing a flow of a procedure for creating a profile in the first embodiment.

FIG. 7 is a diagram illustrating an example of a reference image.

FIG. 8 is a flowchart showing the flow of processing when flash light is emitted.

FIG. 9 is a block diagram schematically illustrating a functional configuration for creating a profile in a computer (or a digital camera).

FIG. 10 is a flowchart showing the flow of processing for creating a profile.

FIG. 11 is a flowchart showing the flow of a process for confirming update of a profile.

FIG. 12 is a block diagram illustrating details of a functional configuration of a profile creation unit illustrated in FIG. 9;

FIG. 13 is a perspective view showing a use mode of a digital camera according to a second embodiment of the present invention.

FIG. 14 is a flowchart showing the flow of a procedure for creating and updating a profile in the second embodiment.

FIG. 15 is a flowchart showing the flow of a procedure for creating and updating a profile in the second embodiment.

FIG. 16 is a flowchart showing the flow of profile creation and update processing when confirming the update of a profile before creating a profile.

[Explanation of symbols]

1 Profile Creation System 2 Digital Camera 3 Computer 3a, 225 Display 8 CD-ROM 9 Printer 31, 231 CPU 32, 232 ROM 33, 234 RAM 51 Reference Image 66 Update Confirmation Unit 212 CCD 215 A / D Conversion Unit 221 Flash 233 331 Program 301 Difference image generation unit 302 Object color component data generation unit 303 Image reproduction unit 304 Profile creation unit 332 Reference image data 333a First image data 333b Second image data 334 Profile 343 Object color component data 511 Color display area 513 Reference mark S12 to S18, S31 to S38, S42 to S46, S
51 to S54, S61 to S69, S181 to S186
Steps

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 1/60 H04N 9/73 Z 5C066 1/46 101: 00 5C077 9/04 9/79 H 5C079 9 / 64 B41J 3/00 B 9A001 9/73 H04N 1/40 D // H04N 101: 00 1/46 Z F term (reference) 2C087 AA15 AB01 AB05 BB10 BD36 CB16 2C262 AA24 AB11 AC04 AC08 BA01 BA09 BC19 EA14 FA13 5B021 AA01 BB02 LG07 LG08 NN23 5C055 AA06 AA14 BA06 BA08 CA03 CA04 EA01 GA00 HA37 JA21 5C065 AA03 BB01 DD02 FF05 GG22 GG26 5C066 AA01 AA11 CA01 GA01 KE02 KE07 KM01 KM10 5C077 LL01 LL12 PP27 PP17 PP17 PP17 MM12 HB01 HB02 HB08 JA11 KA02 LB00 LB01 MA17 NA03 NA11 NA25 PA03 9A001 BB02 BB03 BB04 DD14 EE02 EE05 GG14 HH24 HH31 JJ35 JZ08 KK16 KK37 KK42

Claims (13)

[Claims] 1. A profile creation system for creating a profile for correcting a print color of a printer, comprising: a digital photographing apparatus for acquiring photographed image data by photographing print content printed by a printer in accordance with predetermined reference image data And calculating means for obtaining object color component data obtained by removing the influence of illumination light from the photographed image data; and profile creating means for creating a profile of the printer from the reference image data and the object color component data. Profile creation system characterized by the following. 2. The profile creation system according to claim 1, wherein the digital photographing device has a flash that emits a flash light toward a photographing target, and the photographed image data emits the flash. A first image data obtained by photographing the print content; and a second image data obtained by photographing the print content without emitting the flash. A profile creation system, wherein the object color component data is obtained using two image data. 3. A profile creating system for creating a profile for correcting a print color of a printer, wherein the profile of the printer is created based on image data obtained from print content printed by the printer in accordance with predetermined reference image data. Calculating a difference between a parameter value related to color reproduction in the created profile and a parameter value related to color reproduction in the current profile, and updating the profile if the difference exceeds a predetermined reference. A profile creation system, comprising: a confirmation unit for displaying a message to the effect on a display unit. 4. The profile creation system according to claim 1, wherein the print content includes a plurality of color display areas for displaying different colors from each other. system. 5. The profile creation system according to claim 4, wherein the print content includes a display indicating a reference of a position of the plurality of color display areas. 6. A digital photographing apparatus, comprising: a photographing section for photographing print content printed by a printer in accordance with predetermined reference image data to acquire photographed image data; and detecting an influence of illumination light from the photographed image data. A digital photographing apparatus comprising: an arithmetic unit for calculating the removed object color component data; and a profile generating unit for generating a profile for correcting a print color of the printer from the reference image data and the object color component data. . 7. The digital photographing apparatus according to claim 6, further comprising: a flash that emits a flash light toward a photographing target, wherein the photographed image data emits the flash to photograph the print content. And the second image data obtained by photographing the print content without emitting the flash. The arithmetic unit uses the first and second image data. A digital photographing apparatus for calculating the object color component data by using the digital camera. 8. The digital photographing apparatus according to claim 6, wherein a difference between a value of a parameter relating to color reproduction in a created profile and a value of a parameter relating to color reproduction in a current profile is obtained. A digital photographing apparatus, further comprising: a confirmation unit for displaying on the display unit that the profile should be updated when the difference exceeds a predetermined reference. 9. The digital photographing apparatus according to claim 6, wherein the print content includes a plurality of color display areas displaying different colors from each other. apparatus. 10. A profile creation method for creating a profile for correcting a print color of a printer, the method comprising: taking a print content printed by a printer using a digital photographing device in accordance with predetermined reference image data; Obtaining the object color component data from which the influence of illumination light has been removed from the photographed image data, and creating the profile of the printer from the reference image data and the object color component data. A profile creation method characterized in that: 11. A profile creation method for creating a profile for correcting a print color of a printer, wherein the profile of the printer is created based on image data obtained from print content printed by the printer in accordance with predetermined reference image data. And before or after the step of creating the profile, a difference between a parameter value related to color reproduction in the created profile and a parameter value related to color reproduction in the current profile is determined, and the difference is a predetermined value. Displaying on a display means that the profile should be updated when the standard is exceeded. 12. A recording medium readable by a processing device recording a program for creating a profile for correcting a printing color of a printer by using the processing device, wherein the program causes the processing device to perform a process according to predetermined reference image data. A step of obtaining object color component data obtained by removing the influence of illumination light from photographed image data obtained by photographing print content printed by a printer using a digital photographing device; andthe reference image data and the object color component data. Creating a profile of the printer from the program. 13. A recording medium readable by a processing device which records a program for creating a profile for correcting a print color of a printer using the processing device, wherein the program causes the processing device to execute a process in accordance with predetermined reference image data. Creating a profile of the printer based on image data obtained from print content printed by a printer; and before or after the step of creating the profile, values and current values of parameters related to color reproduction in the created profile. A step of obtaining a difference from a parameter value related to color reproduction in the profile of the profile, and displaying that the profile should be updated when the difference exceeds a predetermined standard;
Recording medium.