JP2007065192A - Image processing method, image processing apparatus, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processing method, an image processing apparatus, and a program enabling easily creating a high accuracy monitor profile. <P>SOLUTION: A display order of two or more display colors for measurement object and timing of displaying display colors for compensation are set and displayed on image display equipment according to the set display order. Here, the colorimetric values of the two or more display colors are compensated by measuring the two or more display colors and those for compensation displayed thereon by a colorimeter and using the white and black colorimetric values of the display colors for compensation corresponding to the respective colorimetric values of the two or more display colors. Further, a display profile is created by calculating display colors of the two or more display colors after compensation from the compensated colorimetric values, creating a gray scale characteristic table of each color from the two or more compensated display colors, and creating color conversion from the compensated colorimetric values. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image processing method, an image processing apparatus, and a program for correcting a display color measurement value of a display device installed under an illumination light source.

  In recent years, an opportunity to output one RGB color image data from various color image display devices including a monitor is increasing. Accordingly, color matching is performed between various color image display devices.

  Currently, a color management system (CMS) that functions on Windows (registered trademark) and Macintosh OS has been introduced. In these CMS, ICC (International Color Consortium) profile is used. Then, by defining the device color relationship between the input and output devices so that the device independent color values on the PCS (profile connection space) match, the colorimetric values for each color image device are matched.

  For example, in the case of a monitor, the profile stores information necessary for conversion between the monitor color signal RGB digital value and the XYZ tristimulus value which is a color space independent of the device. These pieces of information are generally composed of three γ characteristics (tone characteristics (TRC: Tone-Reproduction-Curve)) of RGB channels and a matrix for conversion into XYZ. In order to realize accurate color matching between the two types of monitors, a highly accurate monitor profile is required by accurately approximating these two color reproduction characteristics.

  In the generation of the monitor profile, the TRC characteristic is approximated by a simple γ model or GOG model which is an exponential function obtained by nonlinear optimization in a linear space, or by a 1DLUT of luminance values calculated from RGB signal values. Is generally known. Further, the color conversion matrix from RGB to XYZ is often composed of tristimulus values at the time of the maximum input signal in RGB single color.

  Here, when the monitor profile is generated, the color reproduction characteristic of the monitor is generally measured using a colorimeter such as a spectral radiance meter. However, when black, which is the minimum signal level on a monitor or projector, is displayed, a certain level of luminance value is measured by ambient light reflection on the cathode ray tube surface or screen. Therefore, it may be difficult to approximate the color reproduction characteristics with high accuracy by the above method.

  Therefore, as an improved method to cope with such a problem, a CGO model has been proposed by CIE that approximates a model by subtracting the black tristimulus value, which is the minimum signal level, from the tristimulus value of each measured patch.

As described above, in calculating the color reproduction characteristics of the monitor, various models have been proposed in which a part of the reproduction color is measured and approximated, starting with the above example. However, in any of the methods, in order to approximate device color reproduction with high accuracy, it is necessary to minimize error mixing due to environmental fluctuations and the like during color measurement.
"The Relationship Between Digital and Colorimetric Data for Computer-Controlled CRT Displays2", CIE tech.rep. 1996-122

  In the prior art described above, the tristimulus values of each patch including black are obtained by one measurement. However, the brightness of the illumination light in the actual environment is constantly caused by various factors such as heat generated by the luminaire itself, ambient environmental temperature, voltage fluctuations, or changes over time by the display device itself such as a projector or monitor. It has fluctuated. Moreover, since the white color is constantly changing due to the various factors, the luminance range is also changed.

  Therefore, in the conventional technology that does not take into account changes in illumination light, display device bias, and luminance range over time, variations in illumination light and display device remain in the colorimetric results as errors, so the approximate accuracy of the entire color reproduction model It will cause a decline.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an image processing method, an image processing apparatus, and a program capable of easily creating a high-precision monitor profile. For this reason, the image processing method, the image processing apparatus, and the program according to the present invention correct the fluctuation of the tristimulus value of the monitor minimum signal value (black) and the luminance range easily and accurately.

In order to solve the above problems, the present invention is an image processing method for creating a display profile for an image display device,
A setting step for setting a display order of a plurality of display colors to be measured and a display timing of display colors for correction;
A display step of displaying the plurality of display colors and correction display colors on the image display device according to a set display order;
A colorimetric step of inputting colorimetric values obtained by measuring the plurality of display colors displayed on the image display device and the display color for correction with a colorimeter;
A correction step of correcting the colorimetric values of the plurality of display colors using white and black colorimetric values of the display color for correction corresponding to each of the colorimetric values of the plurality of display colors;
A calculation step of calculating display colors after correction of the plurality of display colors from the corrected colorimetric values;
And a creation step of creating a display profile by creating a gradation characteristic table for each color from a plurality of corrected display colors and creating a color conversion from the measured values after correction.

In order to solve the above problems, the present invention provides an image processing apparatus for creating a display profile for an image display device,
Setting means for setting the display order of a plurality of display colors to be measured and the display timing of the display colors for correction;
Display means for displaying the plurality of display colors and the display color for correction on the image display device according to a set display order;
A colorimetric means for inputting colorimetric values obtained by measuring the plurality of display colors displayed on the image display device and the correction display color with a colorimeter;
Correction means for correcting the colorimetric values of the plurality of display colors using white and black colorimetric values of the display color for correction corresponding to each of the colorimetric values of the plurality of display colors;
Calculation means for calculating display colors after correction of the plurality of display colors from the corrected colorimetric values;
And a creation means for creating a display profile by creating a gradation characteristic table for each color from a plurality of corrected display colors and creating a color conversion from the measured values after correction.

Furthermore, in order to solve the above problems, the present invention provides a computer for creating a display profile for an image display device.
A setting procedure for setting the display order of a plurality of display colors to be measured and the display timing of correction display colors;
A display procedure for displaying the plurality of display colors and correction display colors on the image display device according to a set display order;
A colorimetric procedure for inputting colorimetric values obtained by measuring the plurality of display colors displayed on the image display device and the correction display color with a colorimeter;
A correction procedure for correcting the colorimetric values of the plurality of display colors using white and black colorimetric values of the correction display colors corresponding to the colorimetric values of the plurality of display colors;
A calculation procedure for calculating display colors after correction of the plurality of display colors from the colorimetric values after correction;
A program for creating a gradation characteristic table for each color from a plurality of corrected display colors and creating a display profile by creating a color conversion from the measured values after correction. It is characterized by.

  According to the present invention, it is possible to easily and accurately correct fluctuations in the tristimulus value of the monitor minimum signal value (black) and the luminance range.

  Specifically, by inserting correction measurements at regular intervals in time or measurement order, it is easy to obtain the tristimulus value of the minimum signal value of the monitor or the black level measurement value by reflection of illumination light. Then, the measurement value of the tristimulus value of the maximum signal value is acquired. Then, based on the corrected measurement value, correction for the measurement value of the black level included in the target measurement value and correction for the luminance range are performed. As a result, a highly accurate monitor profile can be created easily.

  Embodiments of the present invention will be described below with reference to the drawings.

<First embodiment>
FIG. 1 is a block diagram showing the configuration of the image processing apparatus according to the first embodiment of the present invention. As shown in FIG. 1, the image processing apparatus includes a CPU 101, a main memory 102, a SCSI interface (I / F) 103, and a network interface 104, which are connected to a PCI bus 114. The HDD 105 is connected to the SCSI interface 103. Further, the image processing apparatus includes a graphic accelerator 106, an RC232C unit 108, and a keyboard / mouse controller 110, which are connected to the PCI bus 114. Furthermore, a color monitor 107 is connected to the graphic accelerator 106. Furthermore, a photometer (colorimeter) 109 is connected to the RC232C unit 108. Furthermore, a keyboard 111 and a mouse 112 are connected to the keyboard / mouse controller 110. The network interface 104 is connected to a local area network (LAN) 113.

  Next, an outline of the monitor profile creation operation in the image processing apparatus having the above configuration will be described. First, an image application stored in the HDD 105 is activated by the CPU 101 based on an OS program that has received a user instruction. Next, a plurality of unsigned 8-bit RGB color data stored in the HDD 105 is transferred to the main memory 102 in accordance with processing in the monitor profile creation application according to a user instruction. This transfer is performed via the PCI bus 114 via the SCSI I / F 103 based on a command from the CPU 101. Alternatively, a plurality of RGB color data stored in a server connected to the LAN or a plurality of RGB color data on the Internet is transferred to the main memory 102. This transfer is performed via the PCI bus 114 via the network I / F 104 according to a command from the CPU 101.

  A plurality of RGB color data held in the main memory 102 is transferred to the graphic accelerator 106 via the PCI bus 114 in response to a command from the CPU 101. Further, the graphic accelerator 106 performs D / A conversion on the digital image data and then transmits the digital image data to the color monitor 107 through the display cable. As a result, a color patch image corresponding to the RGB color data is displayed on the color monitor 107.

  Here, when the user measures the color patch image with the image displayed on the color monitor 107 by the photometer 109, the measurement result is transferred to the HDD 105 via the RC232C unit 108 and stored. At the same time, the fact that the color patch image has been measured is transmitted to the CPU 101. Subsequently, similar processing is performed on a plurality of RGB color data held in the main memory 102 in accordance with processing in the monitor profile creation application. Then, after the measurement of a series of RGB color data is completed, a monitor profile is generated from the measurement values stored in the HDD 105 according to the processing in the monitor profile creation application.

  Next, details of the monitor profile creation operation in the monitor profile creation application with the above configuration will be described. FIG. 2 is a flowchart for explaining the monitor profile creation operation according to the first embodiment of the present invention. The monitor profile creation application in this embodiment measures the RGB signal values held in the main memory 102 by sequentially displaying them on the monitor. Next, correction processing for the black and white level measurement value, gradation conversion creation processing, and conversion creation processing from the RGB color signal values to the device-independent color space are performed. In this embodiment, a monitor profile is created through these four processes. Here, in the following description, the RGB signal value to be displayed on the monitor is particularly referred to as “Private RGB”.

  First, the image processing apparatus is initialized (step S201). Next, the private RGB color information stored in advance in the main memory 102 is displayed on the monitor by the method described later from the monitor profile creation application (step S202). Further, the displayed RGB color information is measured by a colorimeter such as a spectral radiance meter to obtain XYZ data (step S203). Thereafter, the measured value is transferred to the HDD 105.

  Next, it is determined whether or not the measurement has been performed for all the private RGB stored in the main memory 102 (step S204). As a result, when all the measurements have been made (Yes), the process proceeds to step S205, and when there is still an unmeasured private RGB (No), the process returns to step S203 and the above process is repeated.

  In step S205, correction processing related to the black and white level measurement value is performed on each measurement color using the XYZ data for correction measurement. Details of this correction processing will be described later with reference to FIG. Next, from the Y value of the XYZ data corrected in step S205 for the single color signal value, a 1DLUT representing the gradation characteristics is generated for each of the R, G, B single color signals (step S206). Details of the 1DLUT generation process will be described later with reference to FIG. Thereafter, color conversion is created using the XYZ values corrected in step S205 for primary RGB by the method described later (step S207). The details of the color conversion creation process will be described later with reference to FIG. In this way, the present monitor profile creation operation ends.

  Here, the private RGB setting operation of the monitor profile creation application will be described.

  First, the monitor profile creation application stored in the HDD 105 is activated by the CPU 101 based on the OS program that has been instructed by the user. When the monitor profile creation application is activated, a dialog window shown in FIG. 3 is displayed. FIG. 3 is a diagram illustrating an example of a user interface of the color correction parameter creation application. Although the dialog will be described later, the user uses the window shown in FIG. And Private RGB values are confirmed and specified. Here, the measurement color No. When the user who has determined that there is no problem with the private RGB values presses the monitor profile creation button, a monitor profile is generated and stored in the HDD 105.

  Next, the dialog window shown in FIG. 3 will be described. In FIG. And Private RGB values are displayed in a list window, and the measurement color No. is displayed on the left side of the window. Is displayed, and the Private RGB value is displayed on the right side. In the list window 301, the selected measurement color No. And Private RGB values are displayed in reverse video.

  Reference numeral 302 denotes a slide bar. By controlling the bar to move up and down, the measurement color No. And the private RGB values are scrolled to obtain a desired measurement color No. And Private RGB values can be selected. Reference numeral 303 denotes a measurement color file designation button. When this button is pressed, a file describing the RGB values of the measurement color is read, and the measurement value No. And Private RGB values are displayed.

  Furthermore, reference numeral 304 denotes a measurement color editing button. When this button is pressed, a setting dialog shown in FIG. 4 is displayed. FIG. 4 is a diagram illustrating an example of a user interface for setting a reproduction color. From the setting dialog shown in FIG. And Private RGB values are set. Furthermore, reference numeral 305 denotes a correction measurement insertion interval designation window. Using the window, the user selects whether to insert the correction measurement for each number of colors or for each measurement time interval according to the purpose, and designates the interval numerically. Furthermore, reference numeral 306 denotes an output file designation button. When this button is pressed, the output destination of the created monitor profile can be designated. Furthermore, reference numeral 307 denotes a profile creation button, which creates a monitor profile and saves the monitor profile information at the address designated by the output file designation button 606 of the HDD 105. Reference numeral 308 denotes an end button. When this button is pressed, the monitor profile creation application is ended.

  Hereinafter, the operation of the monitor profile creation application will be described with reference to FIG. FIG. 5 is a state diagram showing the operation of the monitor profile creation application.

  First, an initialization operation of reading an initial setting value of target color reproduction information is performed (S501). Next, a user operation determination waiting state in the window of FIG. 3 is entered (S502). Here, when the slide bar 302 is operated, the process proceeds to S503. In S503, the display of the target color reproduction information on the window 301 is scrolled and the selected target color reproduction information is changed according to the control amount of the slider bar.

  If the corrected measurement insertion interval designation window 305 is changed, the process proceeds to S504. In S504, a numerical value indicating an interval is designated according to the selected method.

  Further, when the measurement color file designation button 303 is pressed, the process proceeds to S505. In S505, a file that describes the arrangement order of the measurement colors RGB and the RGB values is designated.

  Furthermore, when the output file designation button 306 is pressed, the process proceeds to S506. In S506, an output file is designated.

  In S507, the dialog shown in FIG. And the private RGB value editing state. Here, the measurement color No. of the color to be edited in the edit box 401 is displayed. And edit the private RGB values in the edit box 402. When the correction button 404 is pressed, the currently selected measurement color No. And the Private RGB value. Further, when the add button 405 is pressed, a new measurement color No. And Private RGB values. When the delete button 406 is pressed, the currently selected measurement color No. And Private RGB values are deleted. When these buttons 404, 405, and 406 are pressed, each operation is performed and stored in the target color reproduction information, and the dialog shown in FIG. 4 is closed.

  On the other hand, when the end button 308 is pressed, the process proceeds to S509. In step S509, after performing an end operation such as releasing the memory, the color correction parameter creation application operation ends.

  Furthermore, when the profile creation button 307 is pressed, the process proceeds to S508. In step S508, gradation conversion and color conversion are created according to the flowchart of FIG.

  FIG. 6 is a flowchart for explaining details of the correction processing for the black and white level measurement value in step S205 of FIG. Hereinafter, the details of the correction process for the black and white level measurement value will be described with reference to FIG.

  First, initial settings such as setting of measurement values acquired in steps S202 to S204 in FIG. 2 and securing of a memory area are performed (step S601). Next, according to the designation (setting) of the correction insertion method in S504, only the measurement value of the correction measurement is extracted (step S602). FIG. 7 is a diagram illustrating an example of a measurement value measured in step S202 and a schematic diagram of 1DLUT. In addition, what inserted correction | amendment measurement for every fixed time is later mentioned as 2nd Example. Here, n represents the number of colors in the insertion interval of the correction measurement set in S504, and k represents the number of correction measurements.

  Next, from the 1DLUT created in step S602, the measurement color No. The monochrome level XYZ corresponding to is calculated using the equation (1) (step S603). Further, the black level XYZ is subtracted from the measured color XYZ using the formula (2). Further, using the equation (3), the measurement color No. The luminance range corresponding to is calculated. Note that the black levels XYZ and 1DLUT corresponding to the measurement value No are stored in the HDD 105 after the calculation.

In the equations (1) to (3), the measurement color No. Is represented by m (m = 1 to j), p is the quotient of m for n, and q is the remainder. The measurement color No. The white level XYZ corresponding to _m is represented by X _{W, m} Y _{W, m} Z _{W, m} . Further, the black level XYZ is represented by X _{Bk, m} Y _{Bk, m} Z _{Bk, m} . Furthermore, the measurement color No. It represents an XYZ corresponding to m is in X _m Y _m Z _m. Furthermore, the corrected measurement color No. XYZ corresponding to _m is represented by X _m 'Y _m ' Z _m '. The luminance range corresponding to m which is is represented by R _m .

  Next, in step S604, the set measurement color No. It is determined whether calculation has been performed for all of the measured values. As a result, when all the calculations have been performed, the process proceeds to step S605, and when there is still remaining, the process proceeds to step S603.

In step S605, the reference range is calculated from the correction measurement value acquired in step S602 and the equation (4). Here, the corrected black and white measurement values are represented as Y _{W, ave} and Y _{bk, ave,} and the luminance range is represented as R _ref .

Next, the measurement color No. A ratio RATE _m between R _m corresponding to _m and R _ref is calculated (step S606). And all measured values No. It is determined whether the ratio RATE _m with R _ref has been calculated for R _m corresponding to (step S607). As a result, when all the calculations are made (Yes), the process proceeds to step S608, and when there is a remaining (No), the process returns to step S606.

In step S608, the measurement color No. X _m 'Y _m ' Z _m 'corresponding to m which is m is multiplied by RATE _m . Further, X _{Bk, m} Y _{Bk, m} Z _{Bk, m} is multiplied by RATE _m .

And all measured values No. It is determined whether the multiplication of RATE _m is calculated for X _m 'Y _m ' Z _m 'corresponding to. All measured values No. It is determined whether the multiplication of RATE _m is calculated for X _{Bk, m} Y _{Bk, m} Z _{Bk, m} corresponding to. As a result, when all the calculations have been performed (Yes), the measurement value correction process is terminated. On the other hand, if there is a remainder (No), the process returns to step S608.

  FIG. 8 is a flowchart for explaining the gradation characteristic creation processing in step S206 of FIG. Hereinafter, the gradation characteristic creation processing will be described with reference to FIG.

First, initialization (initial setting) such as securing a memory area is performed (step S801). Next, a corrected measurement value corresponding to the RGB single color signal value is acquired from the data calculated in step S609 (step S802). Then, the normalized luminance value is calculated using equation (5) (step S803). Here, s (s = 1, 2,..., T) represents the order of RGB single-color signal values. The normalized luminance value of the R signal is Y _R , the normalized luminance value of the G signal is Y _G , and the normalized luminance value of the B signal is Y _B.

  Thereafter, the set measurement value No. It is determined whether normalization has been performed for all the measured values designated (step S804). As a result, if all the calculations have been made (Yes), the process proceeds to step S805, and if there is a remaining (No), the process returns to step S803.

  In step S 805, a 1DLUT corresponding to RGB single color is created using the luminance values calculated in steps S 803 and S 804 and stored in the HDD 105. Then, the measurement value correction process is terminated (step S806).

  FIG. 9 is a flowchart for explaining the color conversion creation processing in step 207 of FIG. Hereinafter, the color conversion creation process will be described with reference to FIG.

  First, correction measurement values for all measurement colors acquired in step S603 are acquired, and initialization (initial setting) such as securing a memory area is performed (step S901). Next, the measurement value after primary RGB correction is extracted from the measurement value acquired in step S901 (step S902).

Further, the color conversion shown in FIG. 10 is created (step S903). FIG. 10 is a diagram illustrating an example of a color conversion matrix. Here, it is assumed that RGB has been subjected to gradation conversion by 1DLUT corresponding to the RGB single color created in step S805. In addition, the measurement XYZ after correction of the input RGB signal value primary RGB is respectively
X _R Y _R Z _R ,
X _G Y _G Z _G ,
X _B Y _B Z _B

Further, the measurement color No. The black level XYZ with respect to is assumed to be X _{Bk, m} Y _{Bk, m} Z _{Bk, m} . Further, the converted XYZ by the color conversion matrix and X _m Y _m Z _m. Then, the color conversion creation process ends (step S904).

  As described above, in the present embodiment, by incorporating correction measurement at regular intervals in the normal monitor measurement, the change in the tristimulus value of the monitor maximum signal value, the tristimulus of the minimum signal value It becomes possible to model the black level measurement value by reflection of the value or illumination light with high accuracy.

  In addition, by applying the above invention, a monitor profile is created that corrects for changes over time and environmental fluctuations without taking into account characteristic fluctuations after energization until the monitoring device or illumination light is stabilized. It becomes possible. This makes it possible to shorten the preparation time for measurement.

  In addition, the target is not limited to CRT monitors, and it is possible to create profiles by modeling high-precision black-and-white level measurement values for all display devices such as LCD monitors, TFT monitors, DLP projectors, LCD projectors, etc. is there.

<Second embodiment>
Here, the process when the correction measurement is inserted at every fixed time in the process in step S603 of FIG. 2 in the first embodiment described above will be described. Below, it demonstrates centering around a different part from a 1st Example. The configuration of the image processing apparatus in this embodiment is the same as that of the image processing apparatus in the first embodiment shown in FIG.

  FIG. 11 is a flowchart for explaining a monochrome level measurement value correction operation when correction measurement is inserted every fixed time in the image processing apparatus according to the second embodiment. The monitor profile creation application in the present embodiment sequentially measures and displays RGB stored in the main memory 102 on the monitor. Then, correction processing for the black level measurement value, gradation conversion creation processing, and conversion processing from the RGB color signal value to the device-independent color space are performed. A monitor profile is created through the above four steps.

  First, in step S202 to step S204, initialization (initial setting) such as acquisition of measurement values and securing of a memory area is performed (step S1101). Next, according to the setting in S504, only the black level measurement value is extracted from the measurement data set in Step S1101 (Step S1102). FIG. 12 is a schematic diagram of the measurement value and 1DLUT measured in step S202.

  Next, the measured value No. is obtained from the 1DLUT created in step S1102. The black and white level XYZ corresponding to is calculated by the equation (6), and the black level XYZ is subtracted from the measured color XYZ by the equation (2) (step S1103). In addition, the measured value No. The luminance range corresponding to is calculated. After the calculation, the measured value No. The black levels XYZ and 1DLUT corresponding to are stored in the HDD 105.

In equation (6), the measurement color No. The measurement time of m corresponding to is represented by u, the insertion time of the correction measurement is represented by v, w is the quotient of u with respect to v, and x is the remainder. The measurement color No. The white level XYZ corresponding to _m is represented by X _{W, m} Y _{W, m} Z _{W, m} . Further, the black level XYZ is represented by X _{Bk, m} Y _{Bk, m} Z _{Bk, m} . Furthermore, the measurement color No. It represents an XYZ corresponding to m is in X _m Y _m Z _m. Furthermore, the corrected measurement color No. XYZ corresponding to _m is represented by X _m 'Y _m ' Z _m '. The luminance range corresponding to m which is is represented as R _m .

  Next, in step S1104, the set measurement value No. It is determined whether calculation has been performed for all of the measured values. As a result, when all the calculations are made (Yes), the process proceeds to step S1105, and when there is a remaining (No), the process returns to step S1103.

Next, the reference range is calculated from the correction measurement value acquired in step S1102 and the equation (4) (step S1104). Here, the corrected black and white measurement values are represented as Y _{W, ave} and Y _{bk, ave,} and the luminance range is represented as R _ref .
And the measured value No. A ratio RATE _m between R _m corresponding to _m and R _ref is calculated (step S1106).

In step S1107, all measurement values No. It is determined whether or not the ratio RATE _m with R _ref has been calculated for R _m corresponding to. As a result, if all of them have been calculated (Yes), the process proceeds to step S1108, and if there is any remaining (No), the process returns to step S1106.

In step S1108, the measurement value No. X _m 'Y _m ' Z _m 'corresponding to m which is m is multiplied by RATE _m . Further, X _{Bk, m} Y _{Bk, m} Z _{Bk, m} is multiplied by RATE _m .

In step S1109, all measurement values No. It is determined whether or not a multiplication of RATE _m is calculated for X _m 'Y _m ' Z _m 'corresponding to. All measured values No. It is determined whether or not the multiplication of RATE _m is calculated for X _{Bk, m} Y _{Bk, m} Z _{Bk, m} corresponding to. As a result, if all of them have been calculated (Yes), the process proceeds to step S1110, and if there is any remaining (No), the process returns to step S1108. In step S1110, the measurement value correction process ends.

  According to the present embodiment, by incorporating correction measurement at regular intervals in the number of colors at regular intervals, the change in the tristimulus value of the monitor maximum signal value, the tristimulus value of the monitor minimum signal value, or It becomes possible to model the black level measurement value by the reflection of the illumination light with high accuracy.

[Other Embodiments]
<Create profile>
In each of the embodiments described above, the CRT monitor profile creation is cited. However, the present invention is not limited to the CRT monitor, and it is also possible to create profiles for display devices such as LCD monitors, TFT monitors, DLP projectors, and LCD projectors. .

<Measurement color for correction>
In each of the above-described embodiments, black and white is used as the measurement color for correction. However, the measurement value for correction may be obtained by combining RGB and other colors.

<Create gradation characteristics>
In each of the above-described embodiments, the RGB single color 1DLUT is used as the gradation characteristic, but it is also possible to use non-linear conversion by γ approximation. It is also possible to combine various operations such as logarithmic operations.

<Create color conversion>
In each embodiment described above, a color conversion matrix is used as the color conversion in step S207. However, in order to shorten the calculation time, it is also possible to use approximate calculation using LUT for color correction conversion. D. L. S. It is possible to create a color conversion matrix that approximates the measured value with high accuracy by applying an optimization method such as a method, an orthogonalization method, or a quasi-Newton method. Furthermore, it is possible to add a constraint condition for storing white or a specific color to the color conversion matrix.

<Others>
Although the embodiment has been described in detail above, the present invention can take an embodiment as a system, apparatus, method, program, storage medium (recording medium), or the like. Specifically, the present invention may be applied to a system composed of a plurality of devices, or may be applied to an apparatus composed of a single device.

  In the present invention, a software program (in the embodiment, a program corresponding to the flowchart shown in the drawing) that realizes the functions of the above-described embodiments is directly or remotely supplied to a system or apparatus. In addition, this includes a case where the system or the computer of the apparatus is also achieved by reading and executing the supplied program code.

  Accordingly, since the functions of the present invention are implemented by computer, the program code installed in the computer also implements the present invention. In other words, the present invention includes a computer program itself for realizing the functional processing of the present invention.

  In that case, as long as it has the function of a program, it may be in the form of object code, a program executed by an interpreter, script data supplied to the OS, or the like.

  Examples of the recording medium for supplying the program include the following. Floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, MO, CD-ROM, CD-R, CD-RW, magnetic tape, nonvolatile memory card, ROM, DVD (DVD-ROM, DVD-R) .

  As another program supply method, the program can be supplied by downloading it from a homepage on the Internet to a recording medium such as a hard disk using a browser of a client computer. That is, it connects to a homepage and downloads the computer program itself of the present invention or a compressed file including an automatic installation function from the homepage. It can also be realized by dividing the program code constituting the program of the present invention into a plurality of files and downloading each file from a different homepage. That is, a WWW server that allows a plurality of users to download a program file for realizing the functional processing of the present invention on a computer is also included in the present invention.

  Further, the program of the present invention is encrypted, stored in a storage medium such as a CD-ROM, and distributed to users. Then, the user who has cleared the predetermined condition is allowed to download key information for decryption from the homepage via the Internet. It is also possible to execute the encrypted program by using the key information and install the program on a computer.

  Further, the functions of the above-described embodiments are realized by the computer executing the read program. In addition, the function of the above-described embodiment can be realized by an OS running on the computer based on an instruction of the program and performing part or all of the actual processing.

  Further, the functions of the above-described embodiments are realized even after the program read from the recording medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. That is, the functions of the above-described embodiments are realized by performing a part or all of the actual processing by the CPU or the like provided in the function expansion board or function expansion unit based on the instructions of the program.

  As described above, in each embodiment of the present invention, black and white by the tristimulus value of the minimum signal value of the monitor or the reflection of the illumination light can be easily performed by inserting the correction measurement every fixed time or fixed color number interval. Get level measurements. Then, by correcting the measurement value of the black and white level included in the target measurement value based on the correction measurement value, a highly accurate monitor profile can be easily created.

  Further, it is possible to create a monitor profile in which a change with time and an environmental change are corrected without taking into consideration a characteristic change after energization until the monitor device or illumination light is stabilized. Thereby, it is possible to shorten the preparation time concerning a measurement.

  Further, the present invention is not limited to a CRT monitor, and it is possible to create a profile by modeling a black level measurement value for all display devices such as an LCD monitor, a TFT monitor, a DLP projector, an LCD projector, and all illumination light with high accuracy. That is, the profile creation means of the present invention can be applied to various display devices, and can flexibly cope with profile creation under various illumination conditions.

1 is a block diagram illustrating a configuration of an image processing apparatus according to a first embodiment of the present invention. It is a flowchart for demonstrating the monitor profile creation operation | movement which concerns on 1st Example of this invention. It is a figure which shows an example of the user interface of a color correction parameter creation application. It is a figure which shows an example of the user interface for a reproduction color setting. It is a state diagram which shows operation | movement of a monitor profile creation application. 3 is a flowchart for explaining details of a correction process for a black and white level measurement value in step S205 of FIG. 2. It is a figure which shows an example of the measured value measured in step S202, and a schematic diagram of 1DLUT. 3 is a flowchart for explaining a tone characteristic creation process in step S206 of FIG. 3 is a flowchart for explaining color conversion creation processing in step 207 of FIG. 2. It is a figure which shows an example of a color conversion matrix. It is a flowchart for demonstrating the monochrome level measured value correction | amendment operation | movement when correction | amendment measurement is inserted for every fixed time in the image processing apparatus which concerns on a 2nd Example. It is the measured value measured by step S202, and the schematic diagram of 1DLUT.

Claims (7)

An image processing method for creating a display profile for an image display device,
A setting step for setting a display order of a plurality of display colors to be measured and a display timing of display colors for correction;
A display step of displaying the plurality of display colors and correction display colors on the image display device according to a set display order;
A colorimetric step of inputting colorimetric values obtained by measuring the plurality of display colors displayed on the image display device and the display color for correction with a colorimeter;
A correction step of correcting the colorimetric values of the plurality of display colors using white and black colorimetric values of the display color for correction corresponding to each of the colorimetric values of the plurality of display colors;
A calculation step of calculating display colors after correction of the plurality of display colors from the corrected colorimetric values;
And a creation step of creating a display profile by creating a gradation characteristic table for each color from a plurality of corrected display colors and creating a color conversion from the measured values after correction. Method.   The image processing method according to claim 1, wherein the setting step sets the display timing so that the correction display color is displayed every time a predetermined number of the plurality of display colors are displayed.   The image processing method according to claim 1, wherein the setting step sets the display timing for displaying the correction display color at predetermined time intervals.   The image processing method according to claim 1, wherein the color measurement step measures tristimulus values of display colors displayed on the image display device to obtain color measurement values of an XYZ color system. The correction step includes
Calculating white and black colorimetric values of the correction display color corresponding to each of the colorimetric values of the plurality of display colors;
Subtracting the black colorimetric value of the corresponding display color for correction from each of the colorimetric values of the plurality of display colors;
Calculating a luminance range corresponding to each of the colorimetric values of the plurality of display colors from a difference between white and black colorimetric values of the corresponding correction display color;
And correcting the colorimetric values of the plurality of display colors by multiplying each of the colorimetric values of the plurality of display colors by a ratio of the luminance range and the average luminance range. Item 8. The image processing method according to Item 1. An image processing apparatus for creating a display profile for an image display device,
Setting means for setting the display order of a plurality of display colors to be measured and the display timing of the display colors for correction;
Display means for displaying the plurality of display colors and the display color for correction on the image display device according to a set display order;
A colorimetric means for inputting colorimetric values obtained by measuring the plurality of display colors displayed on the image display device and the correction display color with a colorimeter;
Correction means for correcting the colorimetric values of the plurality of display colors using white and black colorimetric values of the display color for correction corresponding to each of the colorimetric values of the plurality of display colors;
Calculation means for calculating display colors after correction of the plurality of display colors from the corrected colorimetric values;
Image processing comprising: a creation means for creating a gradation characteristic table for each color from a plurality of corrected display colors and creating a display profile by creating color conversion from the measured values after correction apparatus. On a computer that creates a display profile for an image display device,
A setting procedure for setting the display order of a plurality of display colors to be measured and the display timing of correction display colors;
A display procedure for displaying the plurality of display colors and the display color for correction on the image display device according to a set display order;
A colorimetric procedure for inputting colorimetric values obtained by measuring the plurality of display colors displayed on the image display device and the correction display color with a colorimeter;
A correction procedure for correcting the colorimetric values of the plurality of display colors using white and black colorimetric values of the display color for correction corresponding to each of the colorimetric values of the plurality of display colors;
A calculation procedure for calculating display colors after correction of the plurality of display colors from the colorimetric values after correction;
A program for creating a gradation profile table for each color from a plurality of corrected display colors and creating a display profile by creating a color conversion from the measured values after correction.

Images