JP2022038102A - Calibration device, calibration method, and calibration program - Google Patents

Abstract

A calibration device, a calibration method, and a calibration program for calculating a conversion matrix with a small conversion error due to color conversion are provided. A calibration device (40) includes a third processor, and the third processor (1) spectroscopically measures uniform light from a light source unit (10) with a spectroscopic camera (30) to acquire a measured value; Measure uniform light from the light source unit 10 with a spectrophotometer 20 to obtain reference tristimulus values; (4) associating the calculated conversion matrix with information representing the cumulative operating time of the light source unit 10, and outputting to the spectroscopic camera 30, and performs the above (1) to (4) at least twice at different times. [Selection drawing] Fig. 1

Description

The present invention relates to a calibration device, a calibration method, and a calibration program.

Conventionally, there is known a calibration device that calibrates a camera by calculating a transformation matrix that converts a measured value measured by a camera into a predetermined color coordinate value (see, for example, Patent Document 1).
In the apparatus described in Patent Document 1, a plurality of types of colored light are sequentially output by switching LEDs as a light source, and the RGB values obtained from the two-dimensional sensor for each color and the XYZ values from the spectroscopic apparatus are measured. , Calculate the transformation matrix to convert to RGB and XYZ values.

JP-A-2015-178995

However, in the calibration device and calibration method of Patent Document 1, a conversion process of converting an RGB value into an XYZ value is performed using the same conversion matrix regardless of the color and gradation value of the light from the light source. In this case, there is a problem that a conversion error occurs to the same extent regardless of the color and brightness of the light from the light source, and the influence of the conversion error becomes large particularly when the measured light is a dark color.

The calibrator is a calibrator equipped with at least one processor, and the at least one processor (1) spectrally measures uniform light from a light source unit with a spectroscopic measuring instrument to be calibrated and acquires a measured value. (2) Measuring the uniform light from the light source unit with a calibration reference device to obtain a spectral reference value, and (3) acquiring information representing the cumulative operating time of the light source unit. , (4) Calculate a conversion matrix for color-converting the measured value to a predetermined color coordinate value based on the measured value and the spectral reference value, and (5) calculate the cumulative conversion matrix. It is configured to output to a storage device in association with information representing an operating time, and the light source unit comprises a plurality of types of monochromatic light and a plurality of types of monochromatic light as the uniform light. It is possible to switch to synthetic color light obtained by synthesizing some of the above, and it is possible to change the gradation value of the uniform light. Based on the measured value and the spectral reference value for each of the monochromatic light and the synthetic color light, the conversion matrix for each of the monochromatic light and the synthetic color light is calculated, and the above (1) is performed at least twice at different times. )-(5).

The calibration method is a calibration method for calculating a conversion matrix that color-converts the measured value measured by the spectroscopic measuring instrument into a predetermined color coordinate value. (1) As uniform light, a plurality of types of monochromatic light and a plurality of types are used. The uniform light from the light source unit, which can be switched to synthetic color light obtained by synthesizing some of the monochromatic light and whose gradation value of the uniform light can be changed, is separated by the spectroscopic measuring instrument to be calibrated. Obtaining the measured value by measuring, (2) measuring the uniform light from the light source unit with a calibration reference device to acquire the spectral reference value, and (3) cumulative operating time of the light source unit. (4) The monochromatic light and the composite based on the measured values and the spectral reference values for each of the plurality of types of the monochromatic light and the synthetic color light having different gradation values. The conversion matrix for each of the colored lights is calculated, and (5) the calculated conversion matrix is associated with the information representing the cumulative operating time and output to the storage device at different times. The above (1) to (5) are executed at least twice.

The calibration program is a calibration program that can be read and executed by a computer, and causes the computer to perform the calibration method described above.

The schematic diagram which shows the schematic structure of the calibration system of 1st Embodiment. The block diagram of the calibration system of 1st Embodiment. The figure which shows the state of performing the color correction with the branch school camera of 1st Embodiment. The figure which shows an example of the spectroscopic filter of 1st Embodiment. The flowchart which shows the calibration method of the calibration apparatus of 1st Embodiment. The flowchart which shows the calibration method of the calibration apparatus of 1st Embodiment. The flowchart which shows the image correction process which corrects the image of the display device of 1st Embodiment. The figure which shows an example of the relationship between the correction point of 1st Embodiment, and the measurement point of a display device.

[First Embodiment]
Hereinafter, the first embodiment will be described.
FIG. 1 is a schematic diagram showing a schematic configuration of the calibration system 1 of the first embodiment. FIG. 2 is a block diagram of the calibration system 1.
As shown in FIGS. 1 and 2, the calibration system 1 includes a light source unit 10, a spectrophotometer 20 as a calibration reference device, a spectroscopic camera 30 to be calibrated, and a calibration device 40.

[Structure of light source unit 10]
The light source unit 10 includes a display device 11 and an integrating sphere 12.
The display device 11 is a device that outputs image light. The display device 11 is configured by, for example, a projector.
As shown in FIG. 2, the display device 11 includes an image light generation unit 111, a first communication unit 112, a first memory 113, and a first processor 114.

The image light generation unit 111 includes, for example, a light source, a light separation element, a liquid crystal panel, a photosynthesis element, a projection optical system, and the like.
The light source is composed of a laser light source, a halogen lamp, or the like, and outputs light for generating image light.
The light separation element separates the light output from the light source into R (red), G (green), and B (blue) light.
The liquid crystal panel is provided on each of the optical paths of each color of R, G, and B. This liquid crystal panel is an optical element having a plurality of pixels and capable of changing the light transmittance for each pixel, and changes the light transmittance of each pixel based on the control of the first processor 114.
The photosynthetic element synthesizes the light of each color transmitted through the liquid crystal panel to form the image light.
The projection optical system is configured to include a projection lens and the like, and emits image light to the outside.

The first communication unit 112 communicates with external devices such as the spectroscopic camera 30 and the calibration device 40. The communication method by the first communication unit 112 is not particularly limited, and may be connected to an external device by wire or may communicate with the external device by wireless communication, for example.

The first memory 113 records various programs and various information that control the display device 11. As various information, a reference image output when the spectroscopic camera 30 is calibrated in the calibration system 1, a light source for image information input from an external device, a drive parameter of a liquid crystal panel, and the like are recorded.

The first processor 114 functions as an output control unit 114A, a color measurement command unit 114B, an image correction unit 114C, and the like by reading and executing various programs stored in the first memory 113.

The output control unit 114A controls the image light generation unit 111 to generate image light corresponding to the image information input from the external device and the reference image stored in the first memory 113. At this time, the output control unit 114A generates image light according to the drive parameters stored in the first memory 113.

When the image light is projected onto the projection target from the image light generation unit 111, the color measurement command unit 114B transmits an image pickup command of the spectroscopic image and the position of the measurement point to the spectroscopic camera 30. The measurement points are points for performing color measurement on a spectroscopic image, and for example, a plurality of measurement points are set in a matrix. As a result, the image light projected on the projection target is captured by the spectroscopic camera 30, and the spectroscopic camera 30 performs color conversion processing on the measurement point.

The image correction unit 114C receives the color measurement result for the measurement point from the spectroscopic camera 30, and corrects the drive parameters for driving the image light generation unit 111 based on the received color measurement result.

The integrating sphere 12 is an optical member having a spherical reflecting surface on the inner surface, and has an incident window 121, a first exit window 122, and a second exit window 123. A display device 11 is connected to the incident window 121, and the light output from the display device 11 is incident. A spectrophotometer 20 is connected to the first exit window 122, and a spectroscopic camera 30 is connected to the second exit window 123.
The integrating sphere 12 mixes the image light incident from the display device 11 by reflecting it on the reflecting surface to make the amount of light in the surface uniform. The uniform light, which is the uniformed image light, is emitted from the first exit window 122 to the spectrophotometer 20, and is emitted from the second exit window 123 to the spectroscopic camera 30.

[Structure of spectrophotometer 20]
The spectrophotometer 20 receives the image light output from the integrating sphere 12 and performs spectrophotometric measurement of the image light. The spectrophotometer 20 is a calibration reference device, which performs accurate spectroscopic measurement of incident light and outputs a predetermined color coordinate value as a measurement result.
In the present embodiment, the spectrophotometer 20 outputs the tristimulus value of the incident light as a predetermined color coordinate value.

[Structure of spectroscopic camera 30]
The spectroscopic camera 30 is a spectroscopic measuring instrument to be calibrated by the calibration system 1, and receives image light output from the integrating sphere 12 to capture spectroscopic images for a plurality of wavelengths.

As shown in FIG. 3, the spectroscopic camera 30 of the present embodiment is used to perform color correction of the display device 60 after the calibration process by the calibration system 1 is completed. The display device 60 has the same configuration as the display device 11 used in the calibration process. That is, the display device 60 is a projector including the image light generation unit 111, the first communication unit 112, the first memory 113, and the first processor 114 described above.
More specifically, the spectroscopic camera 30 captures an image projected from the display device 60 onto a projection target 70 such as a screen, and acquires a spectroscopic image corresponding to a plurality of wavelengths. Further, the spectroscopic camera 30 receives the measurement points to be measured in color from the display device 60, calculates the tristimulus values for the measurement points in the spectroscopic image using the transformation matrix set by the calibration system 1, and then calculates the tristimulus values. It is transmitted to the display device 60. As a result, the display device 60 can update the drive parameters and perform color correction based on the tristimulation values for the measurement points.

As shown in FIG. 2, the spectroscopic camera 30 includes an incident optical system 31, a spectroscopic filter 32, an image pickup unit 33, a second communication unit 34, a second memory 35, and a second processor 36.
The incident optical system 31 is configured to include a plurality of lenses into which image light is incident, and guides the incident image light to the spectroscopic filter 32 and the image pickup unit 33.

The spectroscopic filter 32 is a spectroscopic element that transmits light having a predetermined wavelength from the incident image light.
FIG. 4 is a diagram showing an example of the spectroscopic filter 32.
In the present embodiment, as the spectroscopic filter 32, the first substrate 321 and the second substrate 322, the first reflective film 323 provided on the first substrate 321 and the second reflective film 324 provided on the second substrate 322 are used. A tunable Fabry-Perot Etalon equipped with a gap changing unit 325 is used.
In this spectroscopic filter 32, the first reflective film 323 and the second reflective film 324 face each other through a gap, and light having a wavelength corresponding to the size of the gap passes through the spectroscopic filter 32.
The second substrate 322 includes a movable portion 322A provided with the second reflective film 324, and a holding portion 322B that holds the movable portion 322A and moves it back and forth with respect to the first substrate 321.
Further, the gap changing portion 325 is configured by, for example, an electrostatic actuator or the like, and by displacing the movable portion 322A toward the first substrate 321 side, the gap between the first reflective film 323 and the second reflective film 324 is formed. Change the dimensions of. As a result, the wavelength of the light transmitted through the spectroscopic filter 32 also changes.

The image pickup unit 33 has a plurality of image pickup pixels, receives light transmitted through the first reflection film 323 and the second reflection film 324 of the spectroscopic filter 32, and captures a spectroscopic image.

The second communication unit 34 communicates with an external device such as the display devices 11 and 60 and the calibration device 40. The communication method of the second communication unit 34 is not particularly limited, and may be a wired connection or a wireless communication connection.

The second memory 35 is a recording unit that stores various information that controls the spectroscopic camera 30. Specifically, the second memory 35 records a transformation matrix generated by the calibration device 40, a drive table for driving the spectroscopic filter 32, and the like. Further, various programs for controlling the spectroscopic camera 30 are recorded in the second memory 35. A detailed description of the transformation matrix will be described later.

The second processor 36 functions as an image pickup control unit 361, a display information acquisition unit 362, an interpolation unit 363, and a color correction unit 364 by reading and executing a program stored in the second memory 35.
The image pickup control unit 361 controls the spectroscopic filter 32 based on the drive table, and switches the wavelength of the light transmitted through the spectroscopic filter 32. Further, the exposure control of the image pickup unit 33 is performed to capture a spectroscopic image.

The display information acquisition unit 362 acquires the cumulative operating time of the display device 60 from the display device 60, and acquires the color of the image output from the display device 60 as the measurement color.
When the measurement point in the spectroscopic image is designated by the display device 60, the interpolation unit 363 calculates the transformation matrix for the measurement point by interpolation using the predetermined correction point stored in the second memory 35. The correction points are points that generate a transformation matrix on the captured image captured by the imaging unit 33, and a plurality of correction points are set in a matrix.
The color correction unit 364 corrects the color at a predetermined position of the spectroscopic image by using the transformation matrix. Specifically, the color correction unit 364 corrects the measured value with respect to a predetermined position of the spectroscopic image and color-converts it into a tristimulation value.

[Configuration of calibration device 40]
The calibration device 40 is composed of, for example, a computer, and includes a third communication unit 41, a third memory 42, a third processor 43, and the like, as shown in FIG. The third processor 43 may be configured by at least one processor, and may be configured to include a plurality of processors.
The third communication unit 41 is connected to the display device 11, the spectrophotometer 20, and the spectroscopic camera 30, and communicates with these display devices 11, the spectrophotometer 20, and the spectroscopic camera 30.
The third memory 42 stores various programs such as a calibration program and various data for causing the calibration device 40 to perform the calibration process.
The third processor 43 reads and executes the calibration program recorded in the third memory 42, thereby reading and executing the optical output command unit 431, the target color selection unit 432, the measured value acquisition unit 433, the reference value acquisition unit 434, and the exposure compensation unit. It functions as 435, a gradation value extraction unit 436, a normalization processing unit 437, a matrix calculation unit 438, and an operating time acquisition unit 439.

The optical output command unit 431 commands the display device 11 to output image light corresponding to a plurality of reference images. The reference image is an image in which all pixels are composed of predetermined colors. In the present embodiment, a plurality of types of single color reference images in which a predetermined color is a single color and a composite color reference image in which a predetermined color is a composite of a plurality of single colors are used. More specifically, the monochromatic reference image is a monochromatic reference image of each color of red, green, and blue. The composite color reference image is a gray image in which the gradation values of red, green, and blue are set to the same amount. Further, the optical output command unit 431 commands the output of a plurality of images having different gradation values for each single color reference image and the composite color reference image. For example, in the present embodiment, seven patterns of single color reference images having different gradation values are output for the red, green, and blue single color reference images, and eight patterns having different gradation values are output for the gray composite color reference image. Outputs the composite color reference image of.

When the above command is input from the light output command unit 431, the display device 11 outputs the image light of the reference image in response to the command. This image light is homogenized by the integrating sphere 12 to become uniform light. Therefore, as uniform light, the light source unit 10 includes a plurality of types of monochromatic light corresponding to the monochromatic reference image and synthetic color light corresponding to the synthetic color reference image, that is, synthetic color light obtained by synthesizing some of the plurality of types of monochromatic light. It is possible to switch to and change the gradation value of uniform light.

The target color selection unit 432 selects a color to be calculated by the transformation matrix.
The measurement value acquisition unit 433 transmits a spectroscopic measurement command for commanding the imaging of the spectroscopic image to the spectroscopic camera 30, and receives the spectroscopic image from the spectroscopic camera 30. The spectroscopic image obtained from the spectroscopic camera 30 which is a spectroscopic measuring instrument is a measurement result by spectroscopic measurement and includes the measured values of the present disclosure. That is, the gradation value of each pixel of the spectroscopic image corresponds to the measured value of the present disclosure. Upon receiving the spectroscopic measurement command, the spectroscopic camera 30 sequentially switches the transmission wavelength of the spectroscopic filter 32 to capture a spectroscopic image which is an image captured for each wavelength. At this time, a spectroscopic image corresponding to a plurality of wavelengths is acquired with respect to the image light of one reference image. That is, each time the color of the image light emitted from the display device 11 is switched, a spectroscopic image having a plurality of wavelengths is captured. For example, in the present embodiment, as described above, when a command is issued to sequentially output a reference image of 29 colors to the display device 11 and a 16-band spectroscopic image is acquired for each reference image, 29 × 16 spectroscopic images are obtained.

The reference value acquisition unit 434 outputs a reference value measurement command to the spectrophotometer 20 and acquires the spectral reference value which is the measurement result. In the present embodiment, the tristimulus value of the incident light measured by the spectrophotometer 20 is the spectroscopic reference value.

The exposure compensation unit 435 corrects the gradation value of each pixel of the spectroscopic image by dividing it by the exposure time when the image light is captured by the image pickup unit 33 of the spectroscopic camera 30.
In the present embodiment, the spectroscopic camera 30 measures the exposure time when the image light is captured by the image pickup unit 33, associates it with the spectroscopic image, and outputs it to the calibration device 40. The exposure compensation unit 435 corrects the gradation value of each pixel of the spectroscopic image based on the exposure time received together with the spectroscopic image by the measurement value acquisition unit 433.

The gradation value extraction unit 436 extracts the gradation value of a predetermined correction point in a plurality of spectroscopic images as a measured value. This correction point indicates the target coordinates for generating the transformation matrix. The number and positions of the correction points are set in advance and are stored in the third memory 42.
Further, the gradation value extraction unit 436 acquires the gradation values of the correction points and the peripheral pixels thereof in order to suppress the influence of noise in extracting the measured values of the correction points, and the gradation values of these pixels. Let the average of be the measured value for the correction point.

The normalization processing unit 437 normalizes the measured value for the correction point and the spectral reference value by using the brightness value of the image light output from the display device 11.
The matrix calculation unit 438 calculates a transformation matrix for converting the measured value into the spectral reference value for each of the red, green, blue, and gray colors by using the normalized measured value and the spectral reference value. .. The transformation matrix of the present embodiment is a color transformation matrix that converts the gradation value of the correction point of the spectral image into a tristimulus value.
The operating time acquisition unit 439 acquires the cumulative operating time of the display device 11 from the display device 11. The cumulative operating time of the display device 11 corresponds to the cumulative operating time of the light source unit 10.

[Calibration method]
The calibration system 1 of the present embodiment generates a transformation matrix used in the spectroscopic camera 30 to be calibrated.
5A and 5B are flowcharts showing the calibration method of the present embodiment.
In the calibration process of the spectroscopic camera 30, that is, the generation process of the transformation matrix, the calibration worker first connects the display device 11, the spectrophotometer 20, and the spectroscopic camera 30 to the integrating sphere 12, as shown in FIG. , Instruct the calibration device 40 to start the calibration process.
Since the color of the image light output by the display device 11 may change with time, in the calibration process of the present embodiment, a conversion matrix corresponding to the cumulative operating time of the display device 11 is generated. Therefore, the calibration system 1 periodically executes the calibration process while operating the display device 11 in a substantially unused state at the start of calibration for a long period of time. That is, the calibration device 40 executes the process of generating the transformation matrix of each color at least twice at different times.

First, the third processor 43 of the calibration device 40 initializes the cumulative operating time variable rt so that rt = 1 (step S1). The cumulative operating time variable rt is a variable corresponding to the cumulative operating time of the display device 11. The cumulative operating time variable rt is incremented by 1 for each cycle in which the calibration process is executed, and the calibration process is repeated until the cumulative operating time variable rt reaches a predetermined maximum value RTmax. For example, when the calibration process is executed every 1000 hours until the cumulative operating time reaches 10,000 hours, the maximum value RTmax of the cumulative operating time variable rt is set to 10.

Next, the third processor 43 initializes the color variable c indicating the color of the image light to set c = 1 (step S2). The maximum value of the color variable c is C _max . As described above, in the present embodiment, the red, green, blue, and gray reference images are displayed from the display device 11. Here, the color variable and the color of the reference image are associated in advance, and c = _{CR1 to CRM correspond to the red reference image, and c = C G1 to CGM correspond to the} green reference image. Then, c = C _B1 to C _BM correspond to the blue reference image, and c = C _K1 to C _KM correspond to the gray reference image.
For example, when the gradation values of the red, green, and blue single color reference images are changed by 7 patterns each, and the gradation values of the gray composite color reference image are changed by 8 patterns each, C _max = 29. .. Further, for example, C _R1 = 1, _CRM = 7, c = 1 to 7 are variables corresponding to red, C _G1 = 8, C _GM = 14, and c = 8 to 14 are variables corresponding to green. C _B1 = 15, C _BM = 21, c = 15 to 21 are variables corresponding to blue, C _K1 = 22, C _KM = C _max = 29, and c = 22 to 29 are gray. It can be a variable.

Then, the optical output command unit 431 transmits an output command to the display device 11 to emit the image light of the reference image corresponding to the color variable c (step S3). When an image light output command is input from the calibration device 40 to the display device 11 in step S3, the output control unit 114A of the display device 11 controls the image light generation unit 111 based on the drive parameters and sets the color variable c. Image light of the corresponding color is generated and emitted to the integrating sphere 12. Each image light output from the display device 11 in step S3 is a color reference image used when performing color correction of the display device 11.

Further, the reference value acquisition unit 434 of the calibration device 40 outputs a reference value measurement command to the spectrophotometer 20 (step S4). As a result, the spectrophotometer 20 performs spectroscopic measurement of the uniform light emitted from the integrating sphere 12 of the light source unit 10 and outputs a tristimulus value x _C which is a spectral reference value. The tristimulation value x _C , which is a spectral reference value, is hereinafter referred to as a reference tristimulation value x _C.
The reference value acquisition unit 434 acquires the reference tristimulation value x _C from the spectrophotometer 20 (step S5) and stores it in the third memory 42.

Further, the measured value acquisition unit 433 of the calibration device 40 outputs a spectroscopic measurement command to the spectroscopic camera 30 (step S6).
As a result, the spectroscopic camera 30 captures the image light of the uniform light emitted from the integrating sphere 12 of the light source unit 10 to obtain a spectroscopic image. Specifically, the image pickup control unit 361 switches the wavelength of the light transmitted through the spectroscopic filter 32 to a plurality of wavelengths, and acquires a spectroscopic image for each wavelength.
Here, let D ₀ (x, y, c, λ _a ) be a spectroscopic image of the wavelength λ _a with respect to the image light of the color variable c. Note that (x, y) indicates the pixel position of the spectroscopic image. Further, a is a variable corresponding to the wavelength of the spectroscopic image, and the maximum value is a _max . For example, when a 16-band spectroscopic image is taken at intervals of 20 nm from 400 nm to 700 nm, a _max = 16, λ ₁ = 400 nm, λ ₁₆ = 700 nm, and D ₀ (x, y, c, λ ₁ ) to D. 16 spectroscopic images of ₀ (x, y, c, λ ₁₆ ) are obtained.
At this time, the spectroscopic camera 30 measures the exposure time t (c, λ _a ) of the image light to the image pickup unit 33 when the spectroscopic image of each wavelength is captured, and calibrates it in association with the captured spectroscopic image. It is transmitted to the device 40.
The measured value acquisition unit 433 of the calibration device 40 acquires the spectroscopic image _DC0 (x, y, c, λ _a ) from the spectroscopic camera 30 (step S7) and stores it in the third memory 42.

Next, the optical output command unit 431 determines whether or not the color variable c has reached the maximum value C _max of the image light output from the display device 11 (step S8), and if NO in step S8, Add 1 to the variable c and return to step S3. That is, the color of the image light output from the display device 11 is changed, and the processes of steps S3 to S7 are repeated.

If YES is determined in step S8, the matrix calculation step according to steps S9 to S14 is carried out. Specifically, the exposure compensation unit 435 divides the spectroscopic image D ₀ (x, y, c, λ _a ) by the exposure time t (c, λ _a ) as shown in the following equation (1). Exposure correction is performed to obtain a corrected spectroscopic image D (x, y, c, λ _a ) (step S9). As a result, fluctuations in the amount of light due to differences in the exposure time when capturing each image light at each wavelength are corrected.

Next, the gradation value extraction unit 436 extracts the measured values s (i, j, c, λ _a ) with respect to the correction point ( _xi , y _j ), which is the target position for calculating the transformation matrix, from each spectroscopic image. (Step S10). Specifically, the gradation value extraction unit 436 determines the gradation value {s (c, λ _a ) of the pixel such that | x-x _i | ≤Δ, | y-y _j | ≤Δ from each spectroscopic image. } Extract _{i and j} . Δ is a preset value, and for example, when extracting a pixel within one pixel from a correction point, Δ = 1. Then, the average value of the gradation values of these pixels is calculated and used as the measured value s (i, j, c, λ _a ).

Here, in the following description, the measured value s _C and the reference tristimulation value x _C in the spectroscopic image are defined as follows.

After that, the target color selection unit 432 selects a color (target color) to be calculated in the transformation matrix (step S11). For example, when calculating the transformation matrix in the order of red, green, blue, and gray, first, the red reference image of c = _CR1 to _CRM is selected as the target color.
Next, the normalization processing unit 437 outputs the measured value s _C and the reference tristimulation value x _C with respect to the target color selected in step S11, and the image when the image light of the color variable c is output from the display device 11. The light brightness value is divided by _LC and normalized (step S12). Specifically, the normalization processing unit 437 carries out the normalization processing as shown in the following equations (2) to (9).

That is, when the target color selected in step S11 is red, the normalization processing unit 437 has the correction point of each correction point of the spectral image corresponding to each wavelength (λ ₁ to λ _amax ) with respect to one reference image of red. The measured value s _C is divided by the brightness value L _C of the reference image. The normalization processing unit 437 calculates this for each of the red reference images output from the display device 11, and obtains the normalized measurement value _AR for red by the equation (2). Further, the normalization processing unit 437 divides the reference tristimulus value x _C measured by the spectrophotometer 20 for one red image light by the luminance value L _C of the image light, and outputs this from the display device 11. It is calculated for each of the red image lights, and the normalization reference value _BR for the red color is obtained by the equation (3).
The same applies to green, blue, and gray. When green is selected in step S11, the normalized measurement value _AG and the normalized reference value _BG for green are obtained by the equations (4) and (5). When blue is selected in step S11, the normalized measurement value _AB and the normalized reference value B _B for blue are obtained by the equations (6) and (7). When gray is selected in step S11, the normalized measurement value _AK and the normalized reference value _BK for gray are obtained by the equations (8) and (9).
Therefore, the red normalized measurement value A _R is a matrix of a _max × ( _CRM -C _R1 +1), and the green normalized measurement value A _G is a matrix of a _max × (C _GM -C _G1 +1). The blue normalized measurement value A _B is a matrix of a _max × (C _BM − C _B1 +1), and the gray normalized measurement value A _K is a matrix of a _max × (C _KM − C _K1 +1). The red normalization reference value B _R is a 3 × ( _CRM -C _R1 +1) matrix, and the green normalization reference value B _G is a 3 × (C _GM -C _G1 +1) matrix, blue. The normalization reference value B _B is a matrix of 3 × (C _BM − C _B1 +1), and the gray normalization reference value _BK is a matrix of 3 × (C _KM − C _K1 +1). Further, these normalized measurement values _AR , _AG , _AB , _AK and the normalized reference values _BR , _BG , _BB , _BK are calculated by the number of correction points.
After the above, the matrix calculation unit 438 calculates the transformation matrix _MC (i, j) for converting the measured value into the tristimulation value based on the following equations (10) to (13) (step S13). .. The subscript " _C " in the transformation matrix MC (i, j) indicates the color to be corrected. In the case of red, C = R, in the case of green, C = G, and in the case of blue, C = G. , In the case of gray, C = K.

In equations (10) to (13), β is a regularization coefficient for preventing overfitting, and I is an identity matrix of a _max × a _max . The superscript "'" indicates a transposed matrix, and the superscript "-1" indicates an inverse matrix.
In step S13, each transformation matrix _MC (i, j) for the target color selected in step S11 is calculated.

After that, the third processor 43 determines whether or not the transformation matrix _MC (i, j) for all the colors has been calculated (step S14), and the transformation matrix _MC (i, j) has not been calculated. If there is a color, the process returns to step S11, and another target color for which the transformation matrix _MC (i, j) has not been calculated is selected. As described above, the matrix calculation unit 438 uses the transformation matrix MC (i, j) for each color, that is, the red transformation matrix _MR (i, j), the green transformation matrix _MG (i, j), and the blue transformation _{matrix MB} . (I, j) and the gray transformation matrix M _K (i, j) are calculated.

If YES is determined in step S14, the operating time acquisition unit 439 acquires the cumulative operating time of the display device 11 from the display device 11 (step S15).
In addition, in order to shorten the time required for the calibration process, it may be assumed that the calibration process is performed under harsh conditions such as in a hot and humid environment. In this case, a conversion table and a conversion formula for converting the cumulative operating time acquired from the display device 11 into the cumulative operating time under a normal environment are stored in the third memory 42, and these conversion tables and conversion formulas are stored. May be used to convert the cumulative operating time.

Next, the matrix calculation unit 438 uses the calculated transformation matrix MC (i, j) for each color, that is, the red transformation matrix _MR (i, j), the green transformation matrix _MG (i, _j ), and the blue transformation. The matrix MB (i, j) and the gray transformation matrix _{M K} (i, j) are output to the spectroscopic camera 30 in association with the cumulative operating time (step S16). As a result, the spectroscopic camera 30 stores the received transformation matrix M in the second memory 35. In this embodiment, the spectroscopic camera 30 provided with the second memory 35 corresponds to a storage device.

Next, the third processor 43 determines whether or not the cumulative operating time variable rt has reached the maximum value RTmax (step S17), and if YES, ends the calibration.

If NO is determined in step S17, the optical output command unit 431 transmits an output command to the display device 11 to emit a predetermined image light (step S18). Upon receiving this output command, the display device 11 starts emitting a predetermined image light and appropriately updates the cumulative operating time.

After that, the third processor 43 determines whether or not a certain period of time has elapsed with the predetermined image light emitted (step S19). Here, the fixed time is the time corresponding to the cycle of the calibration process, and is, for example, 1000 hours. If YES is determined in step S19, the third processor 43 adds 1 to the variable rt and returns to step S2. On the other hand, if NO is determined, step S19 is repeated.

When the unused display device 11 is used for the above calibration process, the calibration device 40 can also derive the cumulative operating time of the display device 11. Therefore, in this case, the operating time acquisition unit 439 does not need to acquire the cumulative operating time from the display device 11, and acquires the cumulative operating time by its own measurement. Further, when the calculated transformation matrix _MC (i, j) of each color is output in association with the cumulative operating time in step S16, it is changed to the cumulative operating time and associated with the cumulative operating time variable rt. You may. That is, the information to be associated with the transformation matrix _MC (i, j) does not have to be the cumulative operating time itself, but may be information representing the cumulative operating time.

In the calculation of the transformation matrix as described above, since the normalization process is performed in step S12, it is possible to perform color conversion with a small error even for a dark color having a small lightness.
In general, when a human eye perceives a dark color, the color discrimination accuracy is higher in a dark environment than in a bright environment. For example, when displaying an image by irradiating an image light from the display device 11 in a dark place, the human eye more clearly distinguishes the difference in dark color than when displaying the image light in a bright place. be able to. Here, when the normalization process according to step S12 is not performed, the color conversion error when converting the measured value s _C measured by the spectroscopic camera 30 into the tristimulation value is about the same for dark color and light color. In this case, the color conversion error for dark colors in a dark place becomes large, and there is a possibility that the above-mentioned color conversion corresponding to the human eye cannot be performed. On the other hand, in the present embodiment, the color conversion error in a dark place can be suppressed by carrying out the process of step S12. Further, in the present embodiment, each transformation matrix M for red, green, blue, and gray is calculated. Therefore, the accuracy of color correction of each color can be improved as compared with the case where the same transformation matrix is used for all colors.
Further, in the present embodiment, since the transformation matrix is output to the spectroscopic camera 30 in association with the cumulative operating time, the spectroscopic camera 30 uses the transformation matrix according to the change with time of the display device 60 which is the measurement target device. It is possible to perform color measurement with higher accuracy.

[Image correction processing]
Next, the image correction process in the display device 60 and the measurement process in the spectroscopic camera 30 will be described. As shown in FIG. 3, the image correction process includes a display device 60, a projection target 70 such as a screen, and a spectroscopic camera 30.
FIG. 6 is a flowchart showing the image correction process.
When image correction is performed by the display device 60 of the present embodiment, the output control unit 114A controls the image light generation unit 111 to project a predetermined test image onto the projection target 70 (step S21). The test images to be projected are a single color reference image of red, green, and blue, and a composite color reference image of gray.

Next, the color measurement command unit 114B transmits a color measurement request including the position coordinates of the measurement point in the image, the color of the test image to be projected, and the cumulative operating time to the spectroscopic camera 30 (step S22).
Here, FIG. 7 shows the relationship between the correction point P for which the transformation matrix has been calculated by the calibration device 40 and the measurement point Q of the display device 11. In FIG. 7, the correction point P is indicated by a white circle, and the measurement point Q is indicated by a black circle. Further, the outer frame 50 is an outer frame of the captured image captured by the imaging unit 33 of the spectroscopic camera 30. The circle of the broken line is the region where the first reflective film 323 and the second reflective film 324 of the spectroscopic filter 32 overlap in the spectroscopic camera 30, and the light dispersed by the spectroscopic filter 32 in the captured image is incident. The spectral range 51 is shown. In the present embodiment, the spectral range 51 is included inside the outer frame 50 of the captured image captured by the imaging unit 33, but the imaging range is set so that the imaging unit 33 captures a predetermined region within the spectral range 51. You may.
Further, in FIG. 7, the inner frame 52 shows a display image formed by projecting image light from the display device 60 onto the projection target 70. That is, the positions of the display device 60, the spectroscopic camera 30, and the projection target 70 are set so that the display image is included in the spectroscopic range 51.

The display information acquisition unit 362 of the spectroscopic camera 30 acquires the color of the test image included in the color measurement request transmitted in step S22 as the measurement color, and acquires the cumulative operating time of the display device 60 (step S31). ..
Then, the image pickup control unit 361 of the spectroscopic camera 30 acquires a spectroscopic image of the image projected on the projection target 70 (step S32).
Specifically, the image pickup control unit 361 switches the wavelength of the light transmitted through the spectroscopic filter 32 to a plurality of wavelengths, and acquires a spectroscopic image for each wavelength. Further, the image pickup control unit 361 corrects the gradation value by dividing the gradation value of each pixel of the spectroscopic image of each wavelength by the exposure time when the spectroscopic image of the wavelength is imaged.

Further, the image pickup control unit 361 extracts the measured value s _C (m, n, λ _a ) of the measurement point Q with respect to the spectroscopic image of each wavelength (step S33). The subscript "C" indicates the color of the reference image output from the display device 60, and is C = R for red, C = G for green, C = G for blue, and gray. Case C = K. Further, (m, n) represents the position of the measurement point Q. As described above, this color information is included in the measurement request transmitted from the display device 60 in step S22.
Specifically, similarly to step S9 carried out by the calibration device 40, the gradation value {s (λ) of the pixel such that | x-x _m | ≤Δ, | y- _yn | ≤Δ from each spectroscopic image. _a )} Extract _{m and n} . Then, the average value of the gradation values {s (λ _a )} _{m, n} of these pixels is calculated and used as the measured value s _C (m, n, λ _a ).

Next, the interpolation unit 363 acquires the measurement color acquired in step S31 in step S31 based on the plurality of transformation matrices stored in the second memory 35 and the cumulative operating time associated with each. The transformation matrix corresponding to the cumulative operating time is calculated by interpolation (step S34).
Further, the interpolation unit 363 obtains the transformation matrix for the measurement point Q from the transformation matrix for the correction point P by interpolation (step S35).
That is, the transformation matrix stored in the second memory 35 of the spectroscopic camera 30 is for a predetermined correction point P within the spectroscopic range of the spectroscopic image. However, as shown in FIG. 7, the measurement point Q commanded by the display device 11 and the correction point P do not always coincide with each other.
Therefore, as shown in the following equation (14), the interpolation unit 363 changes the transformation matrix M _C (m) of the measurement point Q at the position (m, n) from the transformation matrix M _C (i, j) of the correction point P. , N) is calculated by interpolation.

Then, the color correction unit 364 of the spectroscopic camera 30 uses the transformation matrix _MC (m, n) for the measurement point Q of the spectroscopic image and the measured value s (m, n) of each spectroscopic image for the measurement point Q. , The tristimulus value X (m, n) of the measurement point Q is calculated as shown in the following formula (15) (step S36).

After that, the spectroscopic camera 30 transmits the calculated tristimulation value X (m, n) to the display device 60 (step S37).
When the image correction unit 114C of the display device 60 receives the tristimulus value X (m, n) for the measurement point Q from the spectroscopic camera 30, it compares with the original data of the test image and drives the image light generation unit 111. (Step S23).

[Action and effect of this embodiment]
The calibration device 40 of the present embodiment includes a third processor 43 as at least one processor, and the third processor 43 (1) spectroscopically measures uniform light from the light source unit 10 with a spectroscopic camera 30 to be calibrated. Acquiring the measured value s _C , and (2) measuring the uniform light from the light source unit 10 with the spectrophotometer 20 which is a calibration reference device, and acquiring the reference tristimulus value x _C which is the spectral reference value. And (3) a conversion matrix M _C (i, j) that color-converts the measured value s _C to the tristimulus value X, which is a predetermined color coordinate value, based on the measured value s _C and the reference tristimulus value x _C. The calculation and (4) the calculated conversion matrix _MC (i, j) are associated with the information representing the cumulative operating time of the light source unit 10 and output to the spectroscopic camera 30 so as to be executed. It is configured. Further, the light source unit 10 can switch between a plurality of types of monochromatic light and a synthetic color light obtained by synthesizing some of the plurality of types of monochromatic light as uniform light, and can change the gradation value of the uniform light. In the above (3), the third processor 43 determines each monochromatic light and synthetic colored light based on the measured values s _C and the reference tristimulus values x _C for each of the plurality of types of monochromatic light and synthetic colored light having different gradation values. Conversion matrix _{M C} (i, j) for each of the above, that is, conversion matrix MR (i, j), conversion matrix _MG (i, j), conversion matrix MB (i, j), and conversion matrix _{M K.} It is configured to calculate (i, j) and execute the above (1) to (4) at least twice at different times.

Therefore, in the present embodiment, the transformation matrix _MC (i, j) for each color is calculated. Therefore, when the spectroscopic image of each color is captured by the spectroscopic camera 30, the transformation matrix _MC (corresponding to the color) is calculated. By using i and j), the conversion error when converting the measured value to the tristimulus value can be made extremely small, and highly accurate color measurement can be performed.
Further, in the present embodiment, since the transformation matrix is output to the spectroscopic camera 30 in association with the cumulative operating time, the spectroscopic camera 30 accumulates the display device 60 when measuring the color of the display device 60 which is the measurement target device. It becomes possible to use a transformation matrix according to the operating time, and it becomes possible to perform color measurement with higher accuracy.

In the present embodiment, a spectroscopic camera 30 that captures a spectroscopic image for a plurality of wavelengths is used as a spectroscopic measuring instrument, and the measured value acquisition unit 433 acquires the gradation value of a predetermined correction point in the spectroscopic image as the measured value s _C. do.
As a result, the transformation matrix _{MC (i, j) for each correction point of the spectroscopic image can be calculated, and the color conversion of the measured value s C can} be performed with high accuracy for each correction point.

In the present embodiment, the light source unit 10 includes a display device 11 that outputs image light of a predetermined color, and an integrating sphere 12 that equalizes the image light.
The image light output from the display device 11 includes uneven illumination, but the amount of light of the image light can be made uniform by incidenting it on the integrating sphere 12.

In the present embodiment, the light source unit 10 outputs each color light of red, green, and blue as monochromatic light from the display device 11, and each color light of red, green, and blue as synthetic color light with the same gradation value. Output the combined gray color light. Then, the matrix calculation unit 438 includes a red transformation matrix MR (i, j), a green transformation matrix _MG (i, j), a blue transformation matrix _MB (i, j), and a gray transformation matrix _{M K} (i, j). j) is calculated respectively.
The calibration system 1 of the present embodiment improves the spectral measurement accuracy of the spectroscopic camera 30, and is the image light of a reference image of each color (red, green, blue, gray) used when performing color correction of the display device 60. The conversion matrix _MC (i, j) for each color is calculated based on. This makes it possible to improve the measurement accuracy of the reference image of each color output from the display device 60.

[Second Embodiment]
Next, the second embodiment will be described.
The second embodiment is a calibration system 1 having the same configuration as the first embodiment, and a part of the calibration method in the calibration device 40 is different from the first embodiment.
In the following description, the matters already described will be designated by the same reference numerals, and the description thereof will be omitted or simplified.

Similar to the first embodiment, the calibration system 1 of the second embodiment includes a light source unit 10 including a display device 11 and an integrating sphere 12, a spectrophotometer 20, a spectroscopic camera 30, and a calibration device 40. In this embodiment, the processing of the normalization processing unit 437 and the matrix calculation unit 438 of the calibration device 40 is different from that of the first embodiment.
That is, the calibration device 40 of the present embodiment performs the processes from step S2 to step S10 as in the first embodiment, and acquires the measured value s _C and the reference tristimulus value x _C.
At this time, the calibration device 40 of the present embodiment further outputs a black image, that is, a black image light from the display device 11, and sets the measured value and the reference tristimulus value of each of the black measured values s _BL . And black standard tristimulus value x _BL . As the black image, an image having the lowest gradation value (for example, an image in which the RGB gradation value is set to "0") among the gray images which are the composite color reference images may be used, and the gray image may be used. Alternatively, a black image may be used. Further, black and low-gradation colors of other colors close to black may be output from the display device 11 as a black image group. For example, nine colors of red, green, blue, and gray with the lowest gradation value, an image with the second lowest gradation value, and black may be included in the black image group. .. In the following description, the black image group is represented by "BL".
The measured value s _C , the reference tristimulation value x _C , the black measured value s _BL , and the black reference tristimulation value x _BL have the following components.

Then, in the present embodiment, in step S12, the black component and the color other than black are separated and the normalization process is carried out as shown in the following formulas (16) to (25).

As shown in equations (16) to (23), the normalization processing unit 437 calculates a normalized measurement value A _C for a color component other than black and a normalized reference value B _C. Further, as shown in the equations (24) and (25), the normalization processing unit 437 calculates the black normalization measurement value A _BL for black and the black normalization reference value B _BL . Note that s _BL0 is a measured value for a black image, x _BL0 is a reference tristimulation value for a black image, and L _BL0 is a luminance value for a black image. Further, among the images belonging to the black image group, the images other than the black image are BL1 to BLM. The black normalization measurement value A _BL and the black normalization reference value B _BL are the measurement values of the black image from the measurement values s _BL and the reference tristimulus value x _BL of the images belonging to the black image group other than the black image. It is obtained by subtracting s _BL0 and the reference tristimulus value x _BL0 .
Next, the matrix calculation unit 438 calculates the normal transformation matrix _{MC (i, j) and the black transformation matrix M BL (} i, j) from the following equation (26) by the equation (30).

Further, when performing image correction of the display device 60, substantially the same processing as in the first embodiment is performed.
That is, the display device 60 outputs a test image to the projection target 70 and displays the image in step S21. At this time, first, the display device 60 outputs a black image, performs step S22, and transmits a color measurement request to the spectroscopic camera 30.
As a result, the spectroscopic camera 30 performs steps S31 to S35 on the black image, and calculates the transformation matrix for the measurement point Q by interpolation interpolation. In the interpolation interpolation, the black transformation matrix M _BL (m, n) for the measurement point Q is calculated in substantially the same manner as in the equation (14).

After that, the display device 60 returns to step S21 again, outputs a reference color image other than the black image to the projection target 70 as a test image and displays the image, performs step S22, and measures the color on the spectroscopic camera 30. Send the request.
As a result, the spectroscopic camera 30 performs steps S31 to S35 on the reference image, and calculates the transformation matrix for the measurement point Q by interpolation interpolation. In the interpolation interpolation, the black transformation matrix M _BL (m, n) for the measurement point Q is calculated in substantially the same manner as in the equation (14).

Then, the color correction unit 364 converts the measured value s _C (m, n) at the measurement point Q into the tristimulation value X (m, n) by the following equation (31). Note that s _BL (m, n) is the gradation value of the measurement point Q in the black image. Other processes are the same as those in the first embodiment.

[Action and effect of this embodiment]
In the calibration device 40 of the present embodiment, the light source unit 10 further outputs black image light (black image) on the display device 11. Then, the matrix calculation unit 438 subtracts the measured value s _C of each monochromatic light and the synthetic color light by the measured value s _BL0 for the black image, and sets the reference tristimulus value x _C of each monochromatic light and the synthetic color light to black. After subtracting the reference tristimulus value _{x BL0} for the image, the transformation matrix MC (i, j) for each monochromatic light and synthetic color light is calculated.
In this way, by separately obtaining the normal transformation matrix M _C (i, j) for colors other than black and the black transformation matrix M _BL (i, j) corresponding to black, the measured values for dark colors are tristimulus values. It is possible to further improve the correction accuracy and the color conversion accuracy at the time of color conversion.

[Modification example]
The present invention is not limited to the above-described embodiments, and the present invention includes configurations obtained by modifying, improving, and appropriately combining the respective embodiments within the range in which the object of the present invention can be achieved. It is a thing.

(Modification 1)
In the above embodiment, the transformation matrix is calculated based on the least squares method by the equations (10) to (13) or the equations (26) to (30), but the present invention is not limited to this. The matrix calculation unit 438 may calculate the transformation matrix by using, for example, a principal component regression method or a partial least squares regression method.

(Modification 2)
In the above embodiment, the spectrophotometer 20 measures the tristimulus value as a predetermined color coordinate value, corrects the measured value for the correction point of the spectroscopic camera 30, and calculates a transformation matrix for color conversion to the tristimulus value. , Not limited to this.
For example, the spectrophotometer 20 may be a reference calibrator that measures other color coordinate values such as L * a * b * values and reflectance spectra. In this case, the matrix calculation unit 438 can calculate a transformation matrix that converts the measured value into an L * a * b * value, a reflectance spectrum, or the like.
Further, although the spectrophotometer 20 is used as the calibration reference device, a calibrated spectroscopic camera may be used.

(Modification 3)
In the above embodiment, the spectroscopic camera 30 for performing image correction of the display device 60 that emits image light and the calibration device 40 for calibrating the spectroscopic camera 30 are exemplified, but the present invention is not limited thereto. For example, it may be used as the calibration system 1 of the spectroscopic camera 30 for performing component analysis of an object. In this case, the light source unit 10 may be composed of another light source such as a laser light source or a halogen lamp and an integrating sphere 12 instead of the display device 11.

(Modification example 4)
As the light source unit 10, an example is shown in which image light is incident on the integrating sphere 12 from the display device 11 to generate uniform light, but the present invention is not limited to this. For example, the diffuse reflector that diffusely reflects the light from the light source may be irradiated, and the light reflected by the diffuse reflector may be measured by the spectrophotometer 20 and the spectroscopic camera 30.

(Modification 5)
In the above embodiment, the display device 60 and the spectroscopic camera 30 are provided as separate bodies and are communicably connected by the first communication unit 112 and the second communication unit 34. The spectroscopic camera 30 may be integrally provided.

(Modification 6)
In the above embodiment, the calibration device 40 is configured to include the exposure compensation unit 435, but the image pickup control unit 361 of the spectroscopic camera 30 exposes and corrects the gradation value of the captured spectral image and outputs it to the calibration device 40. It may be configured as follows. In this case, the exposure compensation unit 435 of the calibration device 40 can be eliminated.
Further, if the imaging unit 33 of the spectroscopic camera 30 does not change the exposure time according to the amount of light received, it is not necessary to perform the exposure correction.

(Modification 7)
In the above embodiment, the display device 60 transmits the coordinates of the measurement point Q to the spectroscopic camera 30, and then the spectroscopic image is captured by the spectroscopic camera 30. On the other hand, after the spectroscopic image is captured by the spectroscopic camera 30, the spectroscopic image may be transmitted to the display device 60, and the display device 60 may set the measurement point Q based on the received spectroscopic image. That is, when the spectroscopic camera 30 and the display device 60 are separate bodies, the relative positions of the spectroscopic camera 30 and the display device 60 may change. In this case, the image projected by the display device 60 in the spectroscopic image. The projection range of light may fluctuate. When the display device 60 sets the measurement point Q based on the spectroscopic image, the measurement point Q can be set correctly even if the projection range of the image light fluctuates in the spectroscopic image.

(Modification 8)
In the above embodiment, the transformation matrix is stored in the second memory 35 of the spectroscopic camera 30, and the interpolation unit 363 and the color correction unit 364 of the spectroscopic camera 30 calculate the tristimulus values for the measurement point Q instructed by the display device 60. An example is shown.
On the other hand, the transformation matrix may be stored in the first memory 113 of the display device 60, and the first processor 114 may function as the interpolation unit 363 or the color correction unit 364. In this case, when the spectroscopic camera 30 captures the spectroscopic image, the captured spectroscopic image is transmitted to the display device 60. Then, in the display device 60, the transformation matrix for the measurement point Q is calculated by interpolation, and the tristimulation value for the measurement point Q is calculated.

(Modification 9)
In the above embodiment, the spectroscopic camera 30 is exemplified as the spectroscopic measuring instrument, but it may be a spectroscopic measuring instrument that performs spectroscopic measurement processing on a predetermined measurement point.

(Modification 10)
In the above embodiment, the Fabry-Perot element as shown in FIG. 4 is exemplified as the spectroscopic filter 32, but the present invention is not limited to this. In addition, various spectroscopic elements such as AOTF and LCTF can be used as the spectroscopic filter 32.

(Modification 11)
In the above embodiment, in step S34, the interpolation unit 363 has the cumulative operation acquired in step S31 based on the plurality of transformation matrices stored in the second memory 35 and the cumulative operation time associated with each of them. The transformation matrix corresponding to time is calculated, but the present invention is not limited to this embodiment. For example, the interpolation unit 363 does not execute step S34, and the cumulative operating time associated with the transformation matrix stored in the second memory 35 is shorter than the cumulative operating time acquired in step S31. The transformation matrix for the measurement point Q may be calculated for both of the long times (step S35), and then the transformation matrix corresponding to the cumulative operating time acquired in step S31 may be calculated by interpolation interpolation. Alternatively, the interpolation unit 363 does not execute step S34, and the cumulative operating time associated with the transformation matrix stored in the second memory 35 is shorter than the cumulative operating time acquired in step S31. A transformation matrix for the measurement point Q is calculated for both long times (step S35). Then, the color correction unit 364 calculates the tristimulation value of the measurement point Q for both times (step S36), and then the tristimulation value in the cumulative operating time acquired in step S31 is interpolated. It may be calculated. Alternatively, the interpolating unit 363 does not execute step S34, but instead uses the cumulative operating time acquired in step S31 among the cumulative operating times associated with the transformation matrix stored in the second memory 35 in step S35. The transformation matrix of the measurement point Q may be calculated using the transformation matrix of the closest cumulative operating time.

1 ... Calibration system, 10 ... Light source unit, 11,60 ... Display device, 12 ... Integrating sphere, 20 ... Spectral photometer, 30 ... Spectral camera, 31 ... Incident optical system, 32 ... Spectral filter, 33 ... Imaging unit, 34 ... second communication unit, 35 ... second memory, 36 ... second processor, 40 ... calibration device, 41 ... third communication unit, 42 ... third memory, 43 ... third processor, 50 ... outer frame, 51 ... spectroscopy Range, 52 ... Inner frame, 70 ... Projection target, 111 ... Image light generation unit, 112 ... First communication unit, 113 ... First memory, 114 ... First processor, 114A ... Output control unit, 114B ... Color measurement command unit , 114C ... image correction unit, 121 ... incident window, 122 ... first exit window, 123 ... second exit window, 321 ... first substrate, 322 ... second substrate, 322A ... movable unit, 322B ... holding unit, 323. ... first reflective film, 324 ... second reflective film, 325 ... gap changing unit, 361 ... imaging control unit, 362 ... display information acquisition unit, 363 ... interpolating unit, 364 ... color correction unit, 431 ... optical output command unit, 432 ... Target color selection unit, 433 ... Measurement value acquisition unit, 434 ... Reference value acquisition unit, 435 ... Exposure compensation unit, 436 ... Gradation value extraction unit, 437 ... Normalization processing unit, 438 ... Matrix calculation unit, 439 ... Operating time acquisition unit, P ... correction point, Q ... measurement point.

Claims (7)

A calibration device with at least one processor
The at least one processor
(1) Obtaining the measured value by spectroscopically measuring the uniform light from the light source with a spectroscopic measuring instrument to be calibrated.
(2) To acquire the spectral reference value by measuring the uniform light from the light source unit with a calibration reference device.
(3) Acquiring information representing the cumulative operating time of the light source unit, and
(4) To calculate a transformation matrix for color-converting the measured value into a predetermined color coordinate value based on the measured value and the spectral reference value.
(5) The calculated transformation matrix is associated with the information representing the cumulative operating time and output to the storage device.
Is configured to run
The light source unit can switch between a plurality of types of monochromatic light and a composite color light obtained by synthesizing some of the plurality of types of the monochromatic light as the uniform light, and can change the gradation value of the uniform light. ,
The at least one processor is described in (4) above.
Based on the measured values and the spectroscopic reference values for each of the plurality of types of monochromatic light and the synthetic color light having different gradation values, the transformation matrix for each of the monochromatic light and the synthetic color light was calculated.
It is configured to perform the above (1)-(5) at least twice at different times.
Calibration device. In the calibration device according to claim 1,
The spectroscopic measuring instrument is a spectroscopic camera that captures spectroscopic images for a plurality of wavelengths.
The at least one processor is a calibration device, which acquires a gradation value of a predetermined correction point in the spectroscopic image as the measured value. In the calibration device according to claim 1 or 2.
The light source unit is a calibration device including a display device that outputs image light of a predetermined color and an integrating sphere that equalizes the image light. In the calibration device according to claim 3,
The light source unit outputs red, green, and blue image light as the monochromatic light from the display device, and the same monochromatic light of red, green, and blue as the synthetic color light. Outputs the gray image light synthesized with the gradation value,
The at least one processor is a calibration device for calculating a red transformation matrix for red, a blue transformation matrix for blue, a green transformation matrix for green, and a gray transformation matrix for gray. In the calibration device according to claim 3 or 4.
The light source unit further outputs black image light in the display device.
The at least one processor subtracts the measured value of each monochromatic light and the synthetic color light by the measured value with respect to the black image light, and the spectroscopic reference value of each monochromatic light and the synthetic color light. Is subtracted by the spectral reference value for the black image light, and then the conversion matrix for each monochromatic light and the synthetic color light is calculated. It is a calibration method that calculates a transformation matrix that converts the measured value measured by a spectroscopic measuring instrument into a predetermined color coordinate value.
(1) From a light source unit that can switch between a plurality of types of monochromatic light and a composite color light obtained by synthesizing some of the plurality of types of the monochromatic light, and the gradation value of the uniform light can be changed. To obtain the measured value by spectroscopically measuring the monochromatic light of the above with the spectroscopic measuring instrument to be calibrated.
(2) To acquire the spectral reference value by measuring the uniform light from the light source unit with a calibration reference device.
(3) Acquiring information representing the cumulative operating time of the light source unit, and
(4) Based on the measured values and the spectral reference values for each of the plurality of types of the monochromatic light and the synthetic color light having different gradation values, the transformation matrix for each of the monochromatic light and the synthetic color light is obtained. To calculate and
(5) The calculated transformation matrix is associated with the information representing the cumulative operating time and output to the storage device.
And run
Performing the above (1) to (5) at least twice at different times,
Calibration method. A proofreading program that can be read and executed by a computer.
A calibration program comprising the computer performing the calibration method according to claim 6.

Images