JPH1141478A - Image processing method, apparatus and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To compensate the appearance of colors in a display image in spite of an observation environment by setting an environmental illumination characteristic coefficient based on a manual instruction, correcting environmental light based on an input device, output device and environmental illumination characteristic coefficient concerning input image data depending on the input device, and converting the data to image data depending on a display device. SOLUTION: The image signal inputted from the input device to an image data input part 101 is displayed through an input gamma transforming part 102, image converting part 103 and output gamma transforming part 104 onto an image display part 105. When an external system environment is changed such as changing the input device, image display part 105 or environmental illumination light, the internal functions of the input gamma transforming part 102, image converting part 103 and output gamma transforming part 104 are interactively updated through a user interface part 110. Thus, the color appearance in the image to be displayed on the color display part 105 can be made equal with the image inputted by the input device in spite of the change in the external system environment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image processing method, apparatus, and recording medium for performing a conversion process according to ambient light.

[0002]

2. Description of the Related Art In recent years, color image products have become widespread, and color images can be easily handled not only in special fields such as design creation using CG but also in general offices.
By the way, generally, when an image created on a monitor is output by a printer, the colors of the two do not match, and it is difficult to examine the color of the printed matter on the monitor. As a method for solving this, a color management system has been devised and attracted attention.

[0003] The color management system eliminates color differences between devices by using a common color space. This is because all colors are represented in the same color space, based on the idea that colors that are described by the same coordinates in the same color space have the same appearance, and the corresponding coordinates are By making them match, it is intended to obtain a match in color appearance. At present, one of the methods generally used is CIE-X as a color space.
Using the YZ color space, XYZ which is the internal description coordinate value
There is a method of correcting differences between devices using tristimulus values.

However, when the reproduction media are different, such as in the case of a monitor display material and a print material, the above method may not be sufficient. FIG. 1 shows an environment in which an image is observed using a monitor and printed matter. The same image 202 as the printed matter 201 is displayed on the monitor 203,
explain.

A printed image or an image displayed on a monitor is not always observed under a fixed ambient light, but by opening and closing a window and replacing an illumination light source, the ambient light 20 shown in FIG.
4 changes. This change also changes the appearance of the image. In such a case, even if the color matching can be achieved under a certain ambient light, when the ambient light changes, the color matching feeling is not preserved even if the condition before obtaining the color matching is maintained.

In the above description, a printed matter is compared with a monitor display matter. However, the above-mentioned problems are caused by a case where color expression is performed by reflecting illumination light and a case where color expression is performed by emitting light by itself. Generally occurs in the comparison of That is, it also occurs when a subject such as a person, a sculpture, or a still life is photographed and displayed on a monitor or displayed as a transparent material.

[0007]

As described above, when the image observation environment is changed, the appearance of the image changes. Further, since different media change in different ways, there is a problem that an image that has been given a certain color matching in a certain situation can no longer have a matching color due to a change in the image observation environment.

The present invention has been made in view of the above-mentioned points, and has as its object to compensate for the color appearance of a display image regardless of the observation environment.

It is another object of the present invention to provide a user interface capable of easily setting environmental light correction.

[0010]

In order to achieve the above object, the present invention sets an environmental illumination light characteristic coefficient based on a manual instruction, inputs image data depending on an input device,
The input image data is subjected to environmental light correction based on the input device, the display device, and the environmental illumination light characteristic coefficient, and is converted into image data dependent on the display device.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1) FIG. 2 shows an example of a color image display system embodying the present invention.

The upper half of FIG. 2 mainly shows the flow of image data and signal processing. On the other hand, the lower half of FIG. 2 includes a data storage unit and a data calculation unit for signal processing.

An image data input unit 101 is connected to a scanner, a digital camera, or an image storage device, and receives a subject, a printed matter, a printed matter, and the like as a R _in G _{in Bin} color image signal.

The image signal R input by the image input unit 101
_in G _in B _in, the image signal is corrected by the input gamma conversion unit 102 gamma characteristics of the input device obtained is converted to the system internal input signal _{R in 'G in' B in} '. This conversion is a lookup table conversion for each of the input image signals R _in G _in B _in .

R _in ′ = LUT _Rin (R _in ) G _in ′ = LUT _Gin (G _in ) B _in ′ = LUT _Bin (B _in )

The above-mentioned gamma conversion LUT is stored in the input device characteristic data storage unit 106, and is transmitted to the system control unit 11 via information of the user interface unit 110.
1 is set in the input gamma converter 102.

The system internal input signal R _in 'G _in ' B _in '
Are subjected to the following matrix conversion in the image conversion unit 103 and are converted into system internal output signals R _out 'G _out ' B _out '.

[0019]

[Outside 1]

The conversion matrix MTX _gh is an image obtained from a user interface unit 110, an input device characteristic data storage unit 106, a display device characteristic data storage unit 107, and a conversion matrix calculation data storage unit 108 according to an instruction from the system control unit 111. Using the characteristics of the input device, the image display device, and the observation environment light, the image conversion matrix is calculated by the image conversion matrix calculation unit 109 by a method described later, and is set in the image conversion unit 103. FIG. 3 shows a flow of each data and a calculation result in the above operation.

System internal output signal R _out 'G _out ' B
_out ′ is corrected by the output gamma conversion unit 104 in accordance with the gamma characteristic of the display device on which the signal is output and displayed.
It is converted into an output image signal R _out G _out B _out . This conversion is performed by a system internal output signal R _out 'G _out ' B _out '
This is a look-up table conversion for each signal.

R _out = LUT _Rout (R _out ') G _out = LUT _Gout (G _out ') B _out = LUT _Bout (B _out ')

The above-mentioned gamma conversion look-up table is stored in the display device characteristic data storage unit 107,
It is set in the output gamma converter 104 by the system controller 111.

The image display unit 105 is composed of a monitor such as a CRT or an LCD, and receives an output image signal R _out G _out B _out to display an image.

Hereinafter, the function of the system control unit 111 will be described.

The system control unit 111 controls the operation of the present system.

Further, the system control unit 111 sends the input gamma conversion unit 102 and the output gamma conversion unit 104 to the input gamma conversion unit 102 and the output gamma conversion unit 104 from the input device characteristic data storage unit 106 and the display device characteristic data storage unit 107 via the user interface shown in FIG. , A gamma conversion lookup table corresponding to the input device and a gamma conversion lookup table corresponding to the display device are selected and set.

Further, as shown in FIG. 3, the system control unit 111 controls the user via the user interface shown in FIG.
The following data is sent to the image conversion matrix calculation unit 109 with reference to the input device characteristic data storage unit 107, the display device characteristic data storage unit 108, and the conversion matrix calculation data storage unit 108. The data includes an ambient illumination light color temperature CCT _ks , an ambient illumination light luminance Y _ks , an ambient illumination light characteristic coefficient I
H _ks , a conversion matrix M _in corresponding to the input device (converts the system internal input signal R _in 'G _in ' B _in 'into a system internal conversion signal XYZ), a conversion matrix M _out corresponding to the display device (in the system) The conversion signal XYZ is converted into the system internal output signal R _out 'G _out ' B _out '.) And the tristimulus value X _wm Y _wm Z of the display white of the display device.
_wm , an environmental illumination light characteristic correction matrix CR _hr corresponding to a light source having good color rendering properties, an environmental illumination light characteristic correction matrix CR _hl corresponding to a light source having low color rendering properties, adaptation ratios _s , C
A matrix M _h for converting tristimulus values XYZ of the IEXYZ color system into visual RGB values, and operation coefficients.

[0029] Then, the system controller instructs the calculation of the image transformation matrix MTX _gh the image transformation matrix calculation unit 109 sets the image transformation matrix MTX _gh obtained in the image conversion unit 103.

The system control data storage unit 112 stores a flowchart relating to the operation of the system control unit 111 and a user interface screen, and the system operates in accordance with the flowchart.

The conversion matrix calculation data storage unit 108 stores operation coefficients and an illumination light characteristic correction matrix required for calculating an image conversion matrix.

The image conversion matrix calculation unit 109 calculates an image conversion matrix _{MTXgh in accordance} with an instruction from the system control unit 111 using the data.

[0033] The flow of the data and calculation results when calculating an image transformation matrix MTX _gh shown in FIG.

The image conversion matrix MTX _gh is obtained as a product of a plurality of matrices as follows.

MTX _gh = M _out · M _h ^-1 · D · M _h · CR · M _{in In the} above equation, M _out is a system internal conversion signal XYZ and a system internal output signal R _out 'G for the display device.
_out 'B _out ' is a matrix for converting the system internal conversion signal XYZ that does not depend on the characteristics of the display device into a (suitable) system output signal R _out 'G _out ' B _out which depends on the characteristics of the display device. '.

[0036] M _in, for the input device, the system internal input signal _{R in 'G in' B in} ' a system internal conversion signal X
This is a matrix for conversion into YZ, whereby a system internal input signal R _in 'G _in ' depending on the characteristics of the input device.
B _in 'is converted to a system internal conversion signal X independent of device characteristics.
It can be converted to YZ, and the signal conversion inside the system can be generalized independent of the individual input / output display devices.

M _h is a tristimulus value YXZ in the CIEXYZ color system used as a system internal conversion signal system in the present invention.
Is the response amount R _h G at the light receiver (cone) level of the human eye.
_{hB h} (visual RGB value) is converted into a matrix (basic of color engineering: Asakura Shoten: see page 216). As a result, it is possible to make the image signal correspond to the characteristics of a human, and it is possible to perform signal processing simulating various processes performed by a human at the time of observation.

The CR is _calculated by _{changing the} tristimulus value X _D65 Y _D65 Z _D65 under standard light source (D65) illumination to the tristimulus value X under environmental illumination.
It is a matrix to be converted into _ks Y _ks Z _ks . As a method of converting a tristimulus value under a certain illumination light into a tristimulus value under another illumination light, for example, as shown in chromatic adaptation conversion, a conversion method corresponding to a change in color temperature (for example, Von .Krie
s method). However, even when the color temperature is the same, a certain color may be perceived as a different color, as perceived in image observation under natural daylight and under a daylight fluorescent lamp. Alternatively, even if a color near the achromatic color is given a color matching perception by performing the color adaptation conversion, a certain color may look different. Such a phenomenon is considered to be caused by the spectral distribution characteristics of the illumination light.
IS-Z-8726 (1990) As shown in the color rendering property evaluation method of a light source, the evaluation method is known. The matrix CR used in the present embodiment corrects the difference in color appearance caused by the difference in the spectral distribution characteristics of the illumination light. As a result, the difference in the spectral characteristics of the ambient illumination light can be corrected, and a better color matching can be obtained.

It is desirable that the environmental illumination light characteristic correction matrix CR is obtained for each environmental illumination light in accordance with the actual environment. As a method, for example, using a test chart composed of 77 color patches as shown in FIG. 4, tristimulus values under this illumination light and those tristimulus values under a standard light source are obtained, There is a method of obtaining by optimization such as an attenuation least square method. This method can be easily performed when environmental illumination light is specified in several types. However, in practice, the environmental illumination light changes variously in accordance with the type of the illumination light source, its temporal change, and the change in the state of taking in external light such as sunlight. It is difficult to determine the environmental illumination light characteristic correction matrix corresponding to variously changing environmental illumination light by the above method.

On the other hand, in the present embodiment, the environmental illumination light characteristic correction matrix CR is obtained by the following equation.

CR = IH _ks · CR _hr + (1−IH _ks ) · CR _hl

Here, CR _hr is natural daylight, incandescent lamp, J
This is an environment illumination light characteristic correction matrix corresponding to environment illumination light obtained using a standard light source defined by IS or a light source having good color rendering properties such as a high color rendering type fluorescent lamp defined by JIS. The CR _hr used in the present embodiment is obtained by performing a color matching perception experiment using the algorithm of the present invention under each light source using each environmental illumination light characteristic correction matrix obtained for each light source described above. is there. In the above experiment, under each of the light sources, the correction effect by the environmental illumination light characteristic correction matrix corresponding to each of the light sources showed a good result irrespective of each light source. That is, the light sources corresponding to the above classifications can be handled as a group, and the correction matrix for them can also be handled as a representative one.

CR _hl is an environment illumination light characteristic correction matrix corresponding to environment illumination light obtained using a light source having low color rendering properties, such as a normal fluorescent lamp defined in JIS. The CR _hl used in the present embodiment is obtained by performing a color matching perception experiment using the algorithm of the present invention under each light source using each environmental illumination light characteristic correction matrix obtained for each light source described above. is there. Also in this case, under each of the light sources, the correction effect by the environmental illumination light characteristic correction matrix corresponding to each of the light sources showed a good result regardless of each of the light sources. That is, the light sources corresponding to the above classifications can be handled as a group, and the correction matrix for them can also be handled as a representative one.

In the above equation, IH _ks is an environmental illumination light characteristic coefficient input by the user via the user interface unit 110, and IH _ks takes a number between 0 and 1.

When IH _ks = 0, CR matches CR _hr . In this case, it corresponds to the ambient daylight, incandescent lamp, environmental illumination light obtained by using a light source having good color rendering properties such as a standard light source defined by JIS or a high color rendering type fluorescent lamp defined by JIS. I do.

When IH _ks = 1, CR and CR _hl match. This case corresponds to environmental illumination light obtained using a light source having low color rendering properties such as a normal fluorescent lamp defined by JIS.

If 0 <IH _ks <1, CR is a mixture of CR _hr and CR _hl with IH _ks as the mixing ratio.
In this case, it corresponds to environmental illumination light obtained in a state where the light source having good color rendering properties and the light source having low color rendering properties are mixed at an arbitrary ratio with IH _ks as a ratio. This state is common when it is obtained as normal environmental illumination light.

It has been obtained from the above experiments that a group corresponding to a light source having good color rendering properties and a group corresponding to a light source having low color rendering properties can be treated as one group. At this time, it is considered that the normal state is a mixture of the above two groups. Assuming such a case, a color matching perception experiment was performed under various light sources, using CR as the environmental illumination light characteristic correction matrix for each light source and using the above-described algorithm under each light source. Even in this case,
Under each of the above light sources, the correction effect by each environmental illumination light characteristic correction matrix corresponding to each of the above light sources showed good results.

That is, according to the above-described algorithm, it is possible to obtain an environmental illumination light characteristic correction matrix corresponding to various _types of environmental illumination light using the environmental illumination light characteristic correction coefficient _IHks .

Finally, D is a chromatic adaptation conversion from a state of adapting mainly to a subject, a printed matter, or an observation environment for observing a printed matter to a state adapting to a situation of observing an image on a display device screen. Is a chromatic adaptation conversion diagonal component matrix for performing the following. D is defined by the following equation.

[0051]

[Outside 2] In the above equation, (R ' _hw , G' _hw , B ' _hw ) is a white visual RGB value under the observation environment, and (R _hw , G _hw , B _hw ).
Is the visual RGB value of the reference white when observing the display device. These visual RGB value, by the following equation using the matrix M _h, is determined from the tristimulus values XYZ.

[0052]

[Outside 3] Here, X ′ _w Y ′ _w Z ′ _w is the tristimulus value of the environment illumination light. The tristimulus values are obtained via the user interface unit. It is obtained as shown by the following equation using the ambient illumination light color temperature CCT _ks and the ambient illumination light luminance Y _ks . First, a chromaticity value (x ′ _W , y ′ _w ) is obtained from the ambient illumination light color temperature CCT _ks by the following equation.

[0053]

[Outside 4] Next, based on the chromaticity values (x ′ _W , y ′ _w ) and the ambient illumination light luminance Y _ks , the tristimulus value is obtained by the following equation.

[0054]

[Outside 5]

[0055] On the other hand, X _w Y _w Z _w is a tristimulus value of reference white when the display device observation, tristimulus values X stored _'w Y' _w Z _'w and the display device characteristic data of the ambient light illuminating light Part 10
Displayed tristimulus value X _wm Y _{wm of the} display device obtained from 7
It is obtained by the following equation using Z _wm .

[0056] _{X w = (1-s)} · X 'w + s · X wm Y w = (1-s) · Y' w + s · Y wm Z w = (1-s) · Z 'w + s · Z _When observing the image on the _wm display device screen, the observer does not necessarily adapt only to the display screen, but is considered to adapt to both the display screen and the ambient illumination light at a certain rate, and adapts to the white color on the display screen. Assuming that a ratio, that is, a parameter (adaptation ratio) indicating the influence of the displayed white on the reference white with respect to the observation environment white is s, the tristimulus value X _w Y of the reference white is calculated by the above equation.
_w Z _w can be determined. The adaptation ratio s changes depending on the color temperature of the observation environment light (ambient light) and the background color of the image (display screen background color). For example, when the background color changes from black to white at a gray scale level, the ratio of adaptation to ambient light increases as the background color approaches black. In the present embodiment, the adaptation ratio s is set to 0.
Values ranging from 5 to 0.6 were used.

As described above, the image conversion matrix MT
X _gh is calculated by the image conversion matrix calculation unit 109 using the above data and in accordance with an instruction from the system control unit 111.

Next, the operation of this embodiment will be described.

In the normal operation mode, the present system operates as follows.

FIG. 6 shows an outline of an operation flowchart in the normal operation mode.

The input image signal R
to obtain _{in G in B in (s101)} , the input gamma conversion unit 10
Using an input device gamma characteristic correction look-up table set in advance corresponding to the current system in step 2,
Into a system internal input signal _{R 'in G' in B '} in as described above (s102). Next, the image conversion unit 103 uses an image conversion matrix which is also set in advance,
Convert 'a _in system internal output signal R' within the system input signal R _'in G' _in B to _{out G 'out B' out (} s10
3) The output image signal R _out G _out B _out is obtained as described above by using the display gamma characteristic correction look-up table which is also preset in the output gamma conversion unit 104 (s104), and this is output to the image The information is displayed on the display unit 105 (s105).

When the external environment of the system changes, such as a change in the input device, the display device, or the environment illumination light, the present system selects the user interface mode so as to respond to the changed external environment by using the system internal function. Certain input device gamma characteristic correction look-up tables, display device gamma characteristic correction look-up tables, and image conversion matrices can be updated interactively through the user interface, thereby allowing for changes in the system external environment, The color appearance of the displayed image can be matched.

FIG. 7 is a flow chart showing the operation related to the user interface of the present system.

When the user interface mode of the present system is accessed, the user interface screen information shown in FIG. 5 is read and displayed in s202. Through this user interface screen, the user inputs the input device from the input device column, the display device from the display device column, and the color temperature CC of the ambient illumination light from the column of the ambient illumination light color temperature.
From the column of the luminance of the ambient illumination light, set T _ks to the luminance Y _{ks of the} ambient illumination light.
From the column of environmental illumination light characteristic coefficient,
Enter H _ks . In the screen, a plurality of selection items are prepared in advance in a display field of a downward arrow, and when the downward arrow is selected, a list thereof is displayed. Items are input by selecting a corresponding item in the list. And in s203,
The above information is taken in. At s204, the selection of the execution button is determined. If the execute button is selected, s
Proceeding to 205, the operation flow shown in FIG. 6 is executed. When the execution button is not selected, the process proceeds to s207, and the selection of the end button is determined. If selected, this operation mode ends. If the end button is not selected, the process returns to s203. In s206, the end of the operation is determined, and in the case of ending, the process returns to s203. If not completed, s
At 206, the apparatus waits in a waiting state. The above is the operation related to the user interface mode of the present system.

Next, the operation when executing the user interface mode will be described with reference to FIG.

When execution of the user interface mode is selected, the system control unit 111 reads a program for realizing the operation flowchart of the user interface mode from the system control data storage unit 112 in s301, and starts operation according to the program. First, in s302, an image input device is specified, an input device gamma characteristic correction lookup table corresponding to the image input device is specified, and an input device gamma characteristic correction lookup table corresponding to the input device is selected from the input device characteristic data storage unit 106. Then, it is set in the input gamma converter 102. Further, by selecting from within the system input signal R _in 'G _in' transformation matrix M _in an input device in accordance with the image input device characteristic data storage unit 106 for converting the B _in 'to the system internal conversion signals XYZ,
It is set in the image conversion matrix calculation unit 109. s30
In step 3, an image display device is specified, a display device gamma characteristic correction lookup table corresponding to the image display device is selected from the display device characteristic data storage unit 107, and the output gamma conversion unit 10 is selected.
Set to 4. Further, the system internal conversion signal XYZ corresponding to the image display device is output to the system internal output signal R.
_out 'G _out ' B _out '
_out and the tristimulus values X _wm Y _wm Z _wm of the display white of the display device are selected from the display device characteristic data storage unit 107 and set in the image conversion matrix calculation unit 109. In step S304, the ambient illumination light color temperature CCT _ks , the ambient illumination light luminance Y _ks, and the ambient illumination light characteristic coefficient IH _ks obtained via the user interface are set in the image conversion matrix calculation unit 109. In s305, the illumination light characteristic correction matrix and each operation coefficient necessary for calculating the image conversion matrix are set from the conversion matrix calculation data storage unit 108 to the image conversion matrix calculation unit 109. And in s306,
In each of the data set in the image conversion matrix calculation unit 109 in s302, s303, s304, and s305, the image conversion matrix MT is obtained by the method described above.
Calculating the X _gh, it sets the image transformation matrix MTX _gh obtained in the image conversion unit 103.

Next, using the input device gamma characteristic correction look-up table, display device gamma characteristic correction look-up table, and image conversion matrix set in s302, s303, and s306, the image data input unit 10
1, the input gamma converter 102,
The image conversion unit 103 and the output gamma conversion unit 104 perform image conversion, and the image display unit 106 displays the converted image.
The processing procedure here is the same as the operation in the normal operation mode described above. The above processing is performed in s307, s308, s
309, s310 and s311.

When these operations are completed, the operation returns to the operation relating to the user interface.

Using the system described in this embodiment,
By performing the above operation, a means for obtaining information from the user and an image conversion matrix calculating means are provided, so that the input device, the display device, and the environment illumination light and the like, regardless of the environment outside the system, in that environment. In addition, it is possible to make the color appearance of the object, the printed matter, the printed matter, and the display matter on the display device the same.

In the above embodiment, the color temperature, luminance, and color rendering characteristics of the environment illumination light are input and set from the user interface unit 110, but the environment illumination light sensing unit 114 is provided. Thus, the color temperature, luminance, color rendering characteristics, and the like of the ambient illumination light can be automatically measured and set. This configuration is shown in FIG. In the configuration shown in FIG. 14, a sensor having the sensitivity characteristic shown in FIG. The respective set values (color temperature, luminance, color rendering characteristics) were individually obtained by performing a comparison operation using each signal of the output value BGR of the sensor, and the values were set. In the present configuration, the above setting values are not transmitted from the user interface unit 110 but to the environment illumination light sensing unit 1.
The configuration is almost the same as that of the above-described configuration except that the measurement is made at 14, and then the setting is made, and the operation is also the same.
Further, each of the above set values can be given independently from possible configurations and means. With such a configuration, the characteristics of the environmental illumination light can be set by measurement.

Further, according to the present embodiment, image conversion is performed based on the spectral characteristics of the environment illumination light, and further, color adaptation conversion is performed based on the environment illumination light and the reference white when observing a display object obtained from the display device white. , The spectral characteristics of the observation environment and the color adaptation characteristics of the observer (the reference white when observing the display object is affected by both the display screen white and the ambient light white)
Satisfactorily can be performed.

In the above embodiment, Von. Kries
Is applied to the chromatic adaptation conversion, but another chromatic adaptation prediction theory may be applied. In addition, the present invention is applied to various hardware configurations and sequence processing corresponding thereto. These sequence processes are, for example, logicalized or softwareized, or algorithmized within a range not departing from the gist of the present invention, and can be applied as hardware or a device according to the algorithm.

Further, the present invention can be applied to a copying machine or a printer having a previewer function and having a function of displaying a printed image on a monitor in advance.

(Second Embodiment) In the first embodiment, the image conversion matrix used by the image conversion unit 103 is obtained by the user interface unit. Each time it is set using the input device, the display device, the ambient illumination light color temperature, the ambient illumination light luminance, and the ambient illumination light characteristic coefficient, the image conversion matrix calculation unit 109 obtains it.

It is conceivable that the input device, display device and ambient lighting used are limited to certain combinations. In this case, the combination is a finite combination, and an image conversion matrix can be stored corresponding to each combination.

The present embodiment corresponds to such a case, and an image conversion matrix storage unit 113 is newly added to the color image display system of the first embodiment shown in FIG.

FIG. 9 shows a color image display system according to this embodiment.

The matrix calculated by the image conversion matrix calculation unit 109 is stored in the image conversion matrix storage unit 113 in accordance with an instruction from the user interface unit 110. The system control unit 111 stores the image conversion matrix in the image conversion matrix storage unit 113 from the image conversion matrix calculation unit 109 or sets the image conversion matrix in the image conversion unit 103 from the image conversion matrix storage unit 113 according to the instruction of the user interface unit 110. I do.

The operation of the present embodiment is substantially the same as that of the first embodiment except that a step of storing the calculated image matrix and a step of selecting and storing the stored image conversion matrix are added. .

FIG. 11 is a flowchart showing an operation related to the user interface according to the present embodiment.

FIG. 10 shows a user interface screen according to the present embodiment.

As compared with the screen of the previous embodiment, an input portion for registering and selecting the system external environment is added.
A plurality of selection items are prepared in advance in the display field of the downward arrow, and when the downward arrow is selected, a list thereof is displayed. Items are input by selecting a corresponding item in the list.

The operation of this embodiment will be described below with reference to FIG. When the user interface mode of the present system is accessed, the user interface screen information shown in FIG. 9 is read and displayed in s202. Through this user interface screen, the user inputs the input device from the input device column, the display device from the display device column, and the color temperature CC of the ambient illumination light from the column of the ambient illumination light color temperature.
From the column of the luminance of the ambient illumination light, set T _ks to the luminance Y _{ks of the} ambient illumination light.
From the column of environmental illumination light characteristic coefficient,
Enter H _ks .

Alternatively, system environment data (the above-described input device, display device, and image conversion matrix) stored in advance by means described later is input in the input field for system external environment data.

The above operation is selected by determining whether or not the system external environment is selected in s208.

When the system external environment is not selected, in s203, the input device is entered from the input device column, the display device is entered from the display device column, and the color temperature CCT _{ks of the} ambient illumination light is entered from the ambient illumination light color temperature column. However, the luminance Y _ks of the environmental illumination light is input from the field of the ambient illumination light luminance, and the environmental illumination light characteristic coefficient IH _ks is input from the field of the environmental illumination light characteristic coefficient.

When the system external environment is selected, s2
At 10, system environment data is captured.

Then, it is determined whether or not the execution button has been selected in s204. If the execute button is selected,
Proceeding to s205, the operation flowchart is executed. When the execution button is not selected, the process proceeds to s207, and the selection of the end button is determined. If the end button is selected,
This operation mode ends. S if end button is not selected
Return to 208. At s206, the end of the operation is determined, and if it is, the process proceeds to s209. If not completed, the process waits in a waiting state in s206 until the operation ends.

At s209, it is determined whether or not the current external system environment data is to be stored. If not, the process returns to step 208.

When saving, the system external environment storage name is read from the user interface screen, and the current system external environment data is stored under that name.

The operation related to the user interface mode of the present system has been described above.

Next, the operation when executing the user interface mode will be described with reference to FIG. FIG.
5 is an operation flowchart when the user interface mode is executed in the embodiment.

Basically, compared to the first embodiment, when there is system external environment data, there is only a branch step in which an image conversion matrix is selected from the image conversion matrix storage unit 113 and set in the image conversion unit 103. is there.

Other operations are the same as in the first embodiment.

Using the system described in this embodiment,
By executing the above operation, by providing the selection means by the user, the image conversion matrix calculation means and the storage means, easy setting can be performed regardless of the external environment of the system such as the input device, the display device, and the environment illumination light. Thus, under a certain environment, it is possible to make the color appearance of the subject, the printed matter, and the printed matter the same as the color appearance of the displayed matter on the display device.

(Embodiment 3) In this embodiment, similarly to Embodiment 2, an image conversion matrix is stored corresponding to a combination of an input device, a display device, and environmental lighting to be used.

The color image display system shown in FIG. 9 in which an image conversion matrix storage unit 113 is newly added to the color image display system of the first embodiment shown in FIG. System.

The difference between the second embodiment and the present embodiment is whether or not the image conversion matrix to be used is directly specified by the user interface unit using the system external environment input field.

In the second embodiment, a direct instruction is provided. In the present embodiment, as shown in FIG. 13, a step of analyzing the user interface input data is provided in the system control unit 111, and the result obtained by this is provided. Is the same as the mark in the previously created and stored image conversion matrix, the image conversion matrix is not newly calculated and the previous one is selected.

In this embodiment, when a new image conversion matrix is calculated, the analysis result of the user interface input data is displayed and the image conversion matrix storage 1
13 is stored.

The user interface screen used in this embodiment is the same as that in the first embodiment shown in FIG.

The operation in this embodiment is almost the same as the operation in the above-described second embodiment except for the above.

Using the system described in this embodiment,
By performing the above operation, by providing the image conversion matrix calculation means, the storage means and the user interface input data analysis means, regardless of the external environment of the input device, the display device and the environment illumination light system.
With an easy setting, it is possible to make the color appearance of the subject, the printed matter, the printed matter, and the display matter on the display device the same under a certain environment.

As can be seen from the above embodiments,
In order to make the color appearance of the printed matter on the monitor the same as the color appearance of the printed matter, it is necessary to sufficiently consider the characteristics of the ambient light (spectral characteristics, color rendering properties, etc.) to convert the color signals. The difference between the above embodiments lies in the method of setting data required at the time of conversion. The purpose of the present invention is to set an input device, a display device, and environmental illumination light as an image display method and an image display device / system. A color signal conversion based on the characteristics of the input device, a color signal conversion based on the characteristics of the environment illumination light, and a color signal conversion on the image data based on the set characteristics of the input device, the display device, and the environment illumination light; Another object of the present invention is to provide a color signal conversion unit that performs color signal conversion in consideration of chromatic adaptation based on characteristics of illumination light and display white of a display device, and color signal conversion based on display device characteristics.

More specifically, from the information (chromaticity value, color temperature, spectral intensity (illuminance), etc.) about the illumination light (environmental light), white (under the illumination light) perceived by the illumination light (ambient light) (Such as chromaticity values, XYZ tristimulus values, etc.), information for converting other colors (for example, a two-dimensional matrix, etc.) is obtained, and a color signal is obtained using these information. Perform the conversion.

According to each of the above-described embodiments, it is possible to convert a color signal with high accuracy corresponding to various ambient light sources.
It is possible to obtain the same appearance with sufficient accuracy for the display on the monitor and the print.

Further, the present invention can be applied to various hardware configurations and sequence processing corresponding thereto. These sequence processes are, for example, logicalized or softwareized, or algorithmized without departing from the gist of the present invention, and can be applied as hardware or a device according to the algorithm.

(Other Embodiments) Even if the present invention is applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), it is possible to use a single device (for example, a copying machine, a facsimile machine). May be applied to such a device.

[0109] In order to operate various devices so as to realize the functions of the above-described embodiment, a device connected to the various devices or a computer in the system is provided with software for realizing the functions of the above-described embodiment. The present invention also includes a program code supplied and executed by operating the various devices according to a stored program in a computer (CPU or MPU) of the system or apparatus.

In this case, the program code itself of the software realizes the function of the above-described embodiment, and the program code itself and means for supplying the program code to the computer, for example, the program code The storage medium storing the information constitutes the present invention.

As a storage medium for storing such a program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, magnetic tape, nonvolatile memory card, ROM or the like can be used.

When the computer executes the supplied program code, not only the functions of the above-described embodiments are realized, but also the OS (Operating System) running on the computer or another program. Needless to say, the program code is included in the embodiment of the present invention even when the functions of the above-described embodiment are realized in cooperation with application software or the like.

Further, the supplied program code is stored in a memory provided in a function expansion board of the computer or a function expansion unit connected to the computer, and then stored in the function expansion board or the function storage unit based on the instruction of the program code. It is needless to say that the present invention includes a case where a provided CPU or the like performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0114]

According to the present invention, it is possible to compensate for the color appearance of the displayed image regardless of the observation environment.

Further, by setting the environmental illumination light characteristic coefficient, it is possible to perform environmental light correction according to various observation environments, so that the user can easily set environmental light correction.

[Brief description of the drawings]

FIG. 1 is a diagram showing an image observation environment.

FIG. 2 is a diagram showing a color image display system embodying the present invention.

FIG. 3 is a diagram showing a flow of each data and a calculation result when calculating a matrix MTX _gh .

FIG. 4 shows a 77 used to obtain the coefficients of the matrix CR.
FIG. 3 is a diagram illustrating a test chart including color patches of colors.

FIG. 5 is a diagram showing a user interface screen.

FIG. 6 is a diagram illustrating a flowchart of an operation related to a normal operation mode.

FIG. 7 is a diagram showing a flowchart of an operation related to a user interface mode.

FIG. 8 is a view showing a flowchart of an operation at the time of executing the user interface mode.

FIG. 9 is a diagram illustrating a color image display system according to a second embodiment of the present invention.

FIG. 10 is a diagram showing a user interface screen according to the second embodiment of the present invention.

FIG. 11 is a diagram showing a flowchart of an operation relating to a user interface mode according to the second embodiment of the present invention.

FIG. 12 is a diagram illustrating a flowchart of an operation at the time of executing a user interface mode according to the second embodiment of the present invention.

FIG. 13 is a diagram illustrating a flowchart of an operation at the time of executing a user interface mode according to the third embodiment of the present invention.

FIG. 14 is a diagram illustrating a color image display system according to another embodiment of the first embodiment of the present invention.

FIG. 15 is a diagram illustrating a spectral sensitivity characteristic of a sensor of the environment illumination light sensing unit according to the first embodiment of the present invention.

Claims (8)

[Claims] 1. An environment illumination light characteristic coefficient is set based on a manual instruction, image data depending on an input device is input, and the input image is input based on the input device, a display device, and the environment illumination light characteristic coefficient. An image processing method comprising: performing ambient light correction on data and converting the data into image data dependent on the display device. 2. The image processing method according to claim 1, wherein the environmental light correction performs a color rendering property correction based on the environmental illumination light characteristic coefficient. 3. The image according to claim 2, wherein the color rendering correction is performed by performing a weighting process on the converted data corresponding to the plurality of light sources having different color rendering properties based on the environmental illumination light coefficient. Processing method. 4. The image processing method according to claim 1, wherein a matrix coefficient relating to the environmental light correction is calculated according to the environmental illumination light characteristic coefficient. 5. The image processing method according to claim 4, wherein the calculated matrix coefficients are registered based on a manual instruction. 6. The image processing method according to claim 1, further comprising setting a color temperature and a luminance of ambient light, and performing the environmental light correction by performing a chromatic adaptation conversion process according to the color temperature and luminance. . 7. A setting unit for setting an environmental illumination light characteristic coefficient based on a manual instruction; an input unit for inputting image data depending on an input device; and an input device, a display device, and an environmental illumination light characteristic coefficient. Conversion means for performing ambient light correction on the input image data and converting the input image data into image data dependent on the display device. 8. A recording medium in which a program for executing an image processing method is stored in a state readable by a computer, wherein an environment illumination light characteristic coefficient is set based on a manual instruction, and image data depending on an input device is input. And storing a program that performs ambient light correction on the input image data based on the input device, the display device, and the environmental illumination light characteristic coefficient, and converts the input image data into image data dependent on the display device. Characteristic recording medium.